diff --git a/FixedOrderGen/include/PhaseSpacePoint.hh b/FixedOrderGen/include/PhaseSpacePoint.hh
index f89ab03..4399492 100644
--- a/FixedOrderGen/include/PhaseSpacePoint.hh
+++ b/FixedOrderGen/include/PhaseSpacePoint.hh
@@ -1,298 +1,322 @@
 /** \file      PhaseSpacePoint.hh
  *  \brief     Contains the PhaseSpacePoint Class
  *
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019-2020
  *  \copyright GPLv2 or later
  */
 #pragma once
 
 #include <array>
 #include <bitset>
 #include <cstddef>
 #include <unordered_map>
+#include <optional>
 #include <vector>
 
 #include "boost/iterator/filter_iterator.hpp"
 
 #include "HEJ/Event.hh"
 #include "HEJ/PDG_codes.hh"
 #include "HEJ/Particle.hh"
 
 #include "fastjet/PseudoJet.hh"
 
 #include "Decay.hh"
 #include "Status.hh"
 #include "Subleading.hh"
 
 namespace HEJ {
   class EWConstants;
   class PDF;
   class RNG;
 }
 
 namespace HEJFOG {
   struct JetParameters;
   struct Process;
 
   //! A point in resummation phase space
   class PhaseSpacePoint{
   public:
 
     //! Iterator over partons
     using ConstPartonIterator = boost::filter_iterator<
       bool (*)(HEJ::Particle const &),
       std::vector<HEJ::Particle>::const_iterator
       >;
     //! Reverse Iterator over partons
     using ConstReversePartonIterator = std::reverse_iterator<
                                                 ConstPartonIterator>;
 
     //! Default PhaseSpacePoint Constructor
     PhaseSpacePoint() = delete;
 
     //! PhaseSpacePoint Constructor
     /**
      * @param proc                  The process to generate
      * @param jet_param             Jet defintion & cuts
      * @param pdf                   The pdf set (used for sampling)
      * @param E_beam                Energie of the beam
      * @param subl_chance           Chance to turn a potentially unordered
      *                              emission into an actual one
      * @param subl_channels         Possible subleading channels.
      *                              see HEJFOG::Subleading
      * @param particle_properties   Properties of producted boson
      *
      * Initially, only FKL phase space points are generated. subl_chance gives
      * the chance of turning one emissions into a subleading configuration,
      * i.e. either unordered or central quark/anti-quark pair. Unordered
      * emissions require that the most extremal emission in any direction is
      * a quark or anti-quark and the next emission is a gluon. Quark/anti-quark
      * pairs are only generated for W processes. At most one subleading
      * emission will be generated in this way.
      */
     PhaseSpacePoint(
       Process const & proc,
       JetParameters const & jet_param,
       HEJ::PDF & pdf, double E_beam,
       double subl_chance,
       Subleading subl_channels,
       ParticlesDecayMap const & particle_decays,
       HEJ::EWConstants const & ew_parameters,
       HEJ::RNG & ran
     );
 
     //! Get Weight Function
     /**
      * @returns        Weight of Event
      */
     double weight() const{
       return weight_;
     }
 
     Status status() const{
       return status_;
     }
 
     //! Get Incoming Function
     /**
      * @returns        Incoming Particles
      */
     std::array<HEJ::Particle, 2> const & incoming() const{
       return incoming_;
     }
 
     //! Get Outgoing Function
     /**
      * @returns        Outgoing Particles
      */
     std::vector<HEJ::Particle> const & outgoing() const{
       return outgoing_;
     }
 
     std::unordered_map<std::size_t, std::vector<HEJ::Particle>> const & decays() const{
       return decays_;
     }
 
     //! Iterator to the first outgoing parton
     ConstPartonIterator begin_partons() const;
     //! Iterator to the first outgoing parton
     ConstPartonIterator cbegin_partons() const;
 
     //! Iterator to the end of the outgoing partons
     ConstPartonIterator end_partons() const;
     //! Iterator to the end of the outgoing partons
     ConstPartonIterator cend_partons() const;
 
     //! Reverse Iterator to the first outgoing parton
     ConstReversePartonIterator rbegin_partons() const;
     //! Reverse Iterator to the first outgoing parton
     ConstReversePartonIterator crbegin_partons() const;
     //! Reverse Iterator to the first outgoing parton
     ConstReversePartonIterator rend_partons() const;
     //! Reverse Iterator to the first outgoing parton
     ConstReversePartonIterator crend_partons() const;
 
   private:
     static constexpr std::size_t NUM_PARTONS = 11; //!< Number of partons
   public:
     using part_mask = std::bitset<NUM_PARTONS>; //!< Selection mask for partons
   private:
     friend HEJ::Event::EventData to_EventData(PhaseSpacePoint psp);
     /**
      * @internal
      * @brief Generate LO parton momentum
      *
      * @param np                Number of partons to generate
      * @param is_pure_jets      If true ensures momentum conservation in x and y
      * @param jet_param         Jet properties to fulfil
      * @param max_pt            max allowed pt for a parton (typically E_CMS)
      * @param ran               Random Number Generator
      *
      * @returns                 Momentum of partons
      *
      * Ensures that each parton is in its own jet.
      * Generation is independent of parton flavour. Output is sorted in rapidity.
      */
     std::vector<fastjet::PseudoJet> gen_LO_partons(
         int np, bool is_pure_jets,
         JetParameters const & jet_param,
         double max_pt,
         HEJ::RNG & ran
     );
     HEJ::Particle gen_boson(
         HEJ::ParticleID bosonid, double mass, double width,
+        Process const & proc,
+        std::optional<subleading::Channels> channel,
         HEJ::RNG & ran
     );
     double gen_V_boson_rapidity(HEJ::RNG & ran);
-    double gen_Higgs_rapidity(HEJ::RNG & ran);
+    double gen_Higgs_rapidity(
+      Process const & proc,
+      std::optional<subleading::Channels> channel,
+      HEJ::RNG & ran
+    );
     template<class ParticleMomenta>
     fastjet::PseudoJet gen_last_momentum(
         ParticleMomenta const & other_momenta,
         double mass_square, double y
     ) const;
 
     bool jets_ok(
         std::vector<fastjet::PseudoJet> const & Born_jets,
         std::vector<fastjet::PseudoJet> const & partons
     ) const;
     /**
      * @internal
      * @brief Generate incoming partons according to the PDF
      *
      * @param uf                Scale used in the PDF
      */
     void reconstruct_incoming(
         Process const & proc,
-        double subl_chance, Subleading subl_channels,
+        std::optional<subleading::Channels> channel,
         HEJ::PDF & pdf, double E_beam,
         double uf,
         HEJ::RNG & ran
     );
     HEJ::ParticleID generate_incoming_id(
         std::size_t beam_idx, double x, double uf, HEJ::PDF & pdf,
         part_mask allowed_partons, HEJ::RNG & ran
     );
     //! @brief Returns list of all allowed initial states partons
     std::array<part_mask,2> allowed_incoming(
         Process const & proc,
-        double subl_chance, Subleading subl_channels,
+        std::optional<subleading::Channels> channel,
         HEJ::RNG & ran
     );
 
     //! Ensure that incoming state compatible with A/W/Z production
+    //! Should not be called for final-state qqbar configurations,
+    //! since A/W/Z emission doesn't constrain the initial state there
     std::array<part_mask,2> incoming_AWZ(
-        Process const & proc, Subleading subl_channels,
+        Process const & proc,
         std::array<part_mask,2> allowed_partons,
         HEJ::RNG & ran
     );
     //! Ensure that incoming state compatible with extremal qqbar
     std::array<part_mask,2> incoming_eqqbar(
         std::array<part_mask,2> allowed_partons, HEJ::RNG & ran);
     //! Ensure that incoming state compatible with unordered
     std::array<part_mask,2> incoming_uno(
         std::array<part_mask,2> allowed_partons, HEJ::RNG & ran);
 
     bool momentum_conserved(double ep) const;
 
     bool extremal_FKL_ok(
         std::vector<fastjet::PseudoJet> const & partons
     ) const;
     double random_normal(double stddev, HEJ::RNG & ran);
+    double random_normal_trunc(
+      double stddev,
+      HEJ::RNG & ran,
+      double min,
+      double max
+    );
     /**
      * @internal
      * @brief Turns a FKL configuration into a subleading one
      *
      * @param chance            Chance to switch to subleading configuration
      * @param channels          Allowed channels for subleading process
      * @param proc              Process to decide which subleading
      *                          configurations are allowed
      *
      * With a chance of "chance" the FKL configuration is either turned into
      * a unordered configuration or, for A/W/Z bosons, a configuration with
      * a central quark/anti-quark pair.
      */
-    void maybe_turn_to_subl(double chance, Subleading channels,
-        Process const & proc, HEJ::RNG & ran);
+    void turn_to_subl(
+      subleading::Channels channel,
+      Process const & proc,
+      HEJ::RNG & ran
+    );
     void turn_to_subl(
         Subleading channels,
         bool can_be_uno_backward, bool can_be_uno_forward, bool allow_strange,
         HEJ::RNG & ran);
     void turn_to_uno(bool can_be_uno_backward, bool can_be_uno_forward,
                      HEJ::RNG & ran);
     HEJ::ParticleID select_qqbar_flavour(bool allow_strange, HEJ::RNG & ran);
     void turn_to_cqqbar(bool allow_strange, HEJ::RNG & ran);
     void turn_to_eqqbar(bool allow_strange, HEJ::RNG & ran);
     //! decay where we select the decay channel
     std::vector<HEJ::Particle> decay_channel(
         HEJ::Particle const & parent,
         std::vector<Decay> const & decays,
         HEJ::RNG & ran
     );
     /// @brief setup outgoing partons to ensure correct coupling to boson
     void couple_boson(HEJ::ParticleID boson, HEJ::RNG & ran);
     Decay select_decay_channel(
         std::vector<Decay> const & decays,
         HEJ::RNG & ran
     );
     double gen_hard_pt(
         int np, double ptmin, double ptmax, double y,
         HEJ::RNG & ran
     );
     double gen_soft_pt(int np, double max_pt, HEJ::RNG & ran);
     double gen_parton_pt(
         int count, JetParameters const & jet_param, double max_pt, double y,
         HEJ::RNG & ran
     );
 
     //! Iterator over partons (non-const)
     using PartonIterator = boost::filter_iterator<
       bool (*)(HEJ::Particle const &),
       std::vector<HEJ::Particle>::iterator
       >;
     //! Reverse Iterator over partons (non-const)
     using ReversePartonIterator = std::reverse_iterator<PartonIterator>;
 
     //! Iterator to the first outgoing parton (non-const)
     PartonIterator begin_partons();
     //! Iterator to the end of the outgoing partons (non-const)
     PartonIterator end_partons();
 
     //! Reverse Iterator to the first outgoing parton (non-const)
     ReversePartonIterator rbegin_partons();
     //! Reverse Iterator to the first outgoing parton (non-const)
     ReversePartonIterator rend_partons();
 
+    std::optional<subleading::Channels> select_channel(
+      Subleading subl_channels,
+      double chance,
+      HEJ::RNG & ran
+    );
+
     double weight_;
 
     Status status_;
 
     std::array<HEJ::Particle, 2> incoming_;
     std::vector<HEJ::Particle> outgoing_;
     //! Particle decays in the format {outgoing index, decay products}
     std::unordered_map<std::size_t, std::vector<HEJ::Particle>> decays_;
   };
 
   //! Extract HEJ::Event::EventData from PhaseSpacePoint
   HEJ::Event::EventData to_EventData(PhaseSpacePoint psp);
 } // namespace HEJFOG
diff --git a/FixedOrderGen/src/PhaseSpacePoint.cc b/FixedOrderGen/src/PhaseSpacePoint.cc
index 459fb1f..7ba2e7b 100644
--- a/FixedOrderGen/src/PhaseSpacePoint.cc
+++ b/FixedOrderGen/src/PhaseSpacePoint.cc
@@ -1,1003 +1,1032 @@
 /**
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019-2020
  *  \copyright GPLv2 or later
  */
 #include "PhaseSpacePoint.hh"
 
 #include <algorithm>
 #include <cassert>
 #include <cmath>
+#include <cstdint>
 #include <cstdlib>
 #include <iostream>
 #include <iterator>
 #include <limits>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 
+#include "Subleading.hh"
 #include "fastjet/ClusterSequence.hh"
 
 #include "HEJ/Constants.hh"
 #include "HEJ/EWConstants.hh"
 #include "HEJ/PDF.hh"
 #include "HEJ/PDG_codes.hh"
 #include "HEJ/Particle.hh"
 #include "HEJ/RNG.hh"
 #include "HEJ/exceptions.hh"
 #include "HEJ/kinematics.hh"
 #include "HEJ/utility.hh"
 
 #include "JetParameters.hh"
 #include "Process.hh"
 
 namespace HEJFOG {
   HEJ::Event::EventData to_EventData(PhaseSpacePoint psp){
   //! @TODO Same function already in HEJ
     HEJ::Event::EventData result;
     result.incoming = std::move(psp).incoming_; // NOLINT(bugprone-use-after-move)
     result.outgoing = std::move(psp).outgoing_; // NOLINT(bugprone-use-after-move)
     // technically Event::EventData doesn't have to be sorted,
     // but PhaseSpacePoint should be anyway
     assert(
         std::is_sorted(
             begin(result.outgoing), end(result.outgoing),
             HEJ::rapidity_less{}
         )
     );
     assert(result.outgoing.size() >= 2);
     result.decays = std::move(psp).decays_; // NOLINT(bugprone-use-after-move)
     static_assert(
         std::numeric_limits<double>::has_quiet_NaN,
         "no quiet NaN for double"
     );
     constexpr double nan = std::numeric_limits<double>::quiet_NaN();
     result.parameters.central = {nan, nan, psp.weight()}; // NOLINT(bugprone-use-after-move)
     return result;
   }
 
   PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::begin_partons() const {
     return cbegin_partons();
   }
   PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::cbegin_partons() const {
     return {HEJ::is_parton, cbegin(outgoing()), cend(outgoing())};
   }
 
   PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::end_partons() const {
     return cend_partons();
   }
   PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::cend_partons() const {
     return {HEJ::is_parton, cend(outgoing()), cend(outgoing())};
   }
 
   PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::rbegin_partons() const {
     return crbegin_partons();
   }
   PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::crbegin_partons() const {
     return std::reverse_iterator<ConstPartonIterator>( cend_partons() );
   }
 
   PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::rend_partons() const {
     return crend_partons();
   }
   PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::crend_partons() const {
     return std::reverse_iterator<ConstPartonIterator>( cbegin_partons() );
   }
 
   PhaseSpacePoint::PartonIterator PhaseSpacePoint::begin_partons() {
     return {HEJ::is_parton, begin(outgoing_), end(outgoing_)};
   }
 
   PhaseSpacePoint::PartonIterator PhaseSpacePoint::end_partons() {
     return {HEJ::is_parton, end(outgoing_), end(outgoing_)};
   }
 
   PhaseSpacePoint::ReversePartonIterator PhaseSpacePoint::rbegin_partons() {
     return std::reverse_iterator<PartonIterator>( end_partons() );
   }
 
   PhaseSpacePoint::ReversePartonIterator PhaseSpacePoint::rend_partons() {
     return std::reverse_iterator<PartonIterator>( begin_partons() );
   }
 
   namespace {
     bool can_swap_to_uno(
         HEJ::Particle const & p1, HEJ::Particle const & p2
     ){
       assert(is_parton(p1) && is_parton(p2));
       return p1.type != HEJ::pid::gluon
           && p2.type == HEJ::pid::gluon;
     }
 
-    size_t count_gluons(PhaseSpacePoint::ConstPartonIterator first,
-                        PhaseSpacePoint::ConstPartonIterator last
-    ){
-      return std::count_if(first, last, [](HEJ::Particle const & p)
-        {return p.type == HEJ::pid::gluon;});
-    }
-
-    /** assumes FKL configurations between first and last,
-     * else there can be a quark in a non-extreme position
-     * e.g. uno configuration gqg would pass
-     */
-    Subleading possible_qqbar(
-      PhaseSpacePoint::ConstPartonIterator first,
-      PhaseSpacePoint::ConstReversePartonIterator const & last
-    ){
-      using namespace subleading;
-      assert( std::distance( first,last.base() )>2 );
-      Subleading channels = ALL;
-      channels.reset(eqqbar);
-      channels.reset(cqqbar);
-      auto const ngluon = count_gluons(first,last.base());
-      if(ngluon < 2) return channels;
-      if(first->type==HEJ::pid::gluon || last->type==HEJ::pid::gluon){
-        channels.set(eqqbar);
-      }
-      if(std::distance(first,last.base())>=4){
-        channels.set(cqqbar);
-      }
-      return channels;
-    }
-
     template<class PartonIt, class OutIt>
     bool uno_possible(
       PartonIt first_parton, OutIt first_out
     ){
       using namespace HEJ;
       // Special case: Higgs can not be outside of uno
       if(first_out->type == pid::Higgs
           || std::next(first_out)->type==pid::Higgs){
         return false;
       }
       // decide what kind of subleading process is allowed
       return can_swap_to_uno( *first_parton, *std::next(first_parton) );
     }
 
     bool is_AWZ_proccess(Process const & proc){
       return proc.boson && HEJ::is_AWZ_boson(*proc.boson);
     }
 
     bool is_up_type(HEJ::Particle const & part){
       return is_anyquark(part) && ((std::abs(part.type)%2) == 0);
     }
     bool is_down_type(HEJ::Particle const & part){
       return is_anyquark(part) && ((std::abs(part.type)%2) != 0);
     }
     bool can_couple_to_W(
         HEJ::Particle const & part, HEJ::pid::ParticleID const W_id
     ){
       const int W_charge = W_id>0?1:-1;
       return std::abs(part.type)<HEJ::pid::b
         && ( (W_charge*part.type > 0 && is_up_type(part))
           || (W_charge*part.type < 0 && is_down_type(part)) );
     }
-
-    Subleading ensure_AWZ(
-        double & subl_chance, bool & allow_strange,
-        HEJ::ParticleID const boson,
-        PhaseSpacePoint::ConstPartonIterator first_parton,
-        PhaseSpacePoint::ConstPartonIterator last_parton
-    ){
-      auto channels = subleading::ALL;
-      if(std::none_of(first_parton, last_parton,
-          [&boson](HEJ::Particle const & p){
-            return can_couple_to_W(p, boson);})) {
-        // enforce qqbar if A/W/Z can't couple somewhere else
-        // this is ensured to work through filter_partons in reconstruct_incoming
-        channels.reset(subleading::uno);
-        assert(channels.any());
-        subl_chance = 1.;
-        // strange not allowed for W
-        if(std::abs(boson)== HEJ::pid::Wp) allow_strange = false;
-      }
-      return channels;
-    }
   } // namespace
 
-  void PhaseSpacePoint::turn_to_subl(
-      Subleading const channels,
-      bool const can_be_uno_backward, bool const can_be_uno_forward,
-      bool const allow_strange,
-      HEJ::RNG & ran
-  ){
-    double const nchannels = channels.count();
-    double const step = 1./nchannels;
-    weight_*=nchannels;
-    unsigned selected = subleading::first;
-    double rnd = nchannels>1?ran.flat():0.;
-    // @TODO optimise this sampling
-    for(; selected<=subleading::last; ++selected){
-      assert(rnd>=0);
-      if(channels[selected]){
-        if(rnd<step) break;
-        rnd-=step;
-      }
-    }
-    switch(selected){
-      case subleading::uno:
-        return turn_to_uno(can_be_uno_backward, can_be_uno_forward, ran);
-      case subleading::cqqbar:
-        return turn_to_cqqbar(allow_strange, ran);
-      case subleading::eqqbar:
-        return turn_to_eqqbar(allow_strange, ran);
-      default:
-        throw std::logic_error{"unreachable"};
+  namespace {
+    template<class Iterator>
+    bool allow_strange(
+      Iterator first_parton, Iterator last_parton,
+      Process const & proc
+    ) {
+      const auto boson = proc.boson;
+      return !(
+        boson
+        && std::abs(*boson)== HEJ::pid::Wp
+        && std::none_of(
+          first_parton, last_parton,
+          [boson](HEJ::Particle const & p){
+            return can_couple_to_W(p, *boson);
+          })
+      );
     }
   }
 
-  void PhaseSpacePoint::maybe_turn_to_subl(
-      double chance, Subleading channels, Process const & proc, HEJ::RNG & ran
-  ){
+  void PhaseSpacePoint::turn_to_subl(
+      subleading::Channels const channel,
+      Process const & proc,
+      HEJ::RNG & ran
+  ) {
     using namespace HEJ;
-    if(proc.njets <= 2) return;
-    assert(outgoing_.size() >= 2);
+    assert(proc.njets > 2);
 
-    // decide what kind of subleading process is allowed
-    bool const can_be_uno_backward = uno_possible(cbegin_partons(),
+    switch(channel) {
+    case subleading::unordered: {
+      bool const can_be_uno_backward = uno_possible(cbegin_partons(),
                                                   outgoing_.cbegin());
-    bool const can_be_uno_forward  = uno_possible(crbegin_partons(),
+      bool const can_be_uno_forward  = uno_possible(crbegin_partons(),
                                                   outgoing_.crbegin());
-    if(channels[subleading::uno]){
-      channels.set(subleading::uno, can_be_uno_backward || can_be_uno_forward);
+      return turn_to_uno(can_be_uno_backward, can_be_uno_forward, ran);
     }
-    channels &= possible_qqbar(cbegin_partons(), crbegin_partons());
-
-    bool allow_strange = true;
-    if(is_AWZ_proccess(proc)) {
-      channels &= ensure_AWZ(chance, allow_strange, *proc.boson,
-                             cbegin_partons(), cend_partons());
+    case subleading::central_qqbar: {
+      bool const strange_allowed = allow_strange(
+        begin_partons(),
+        end_partons(),
+        proc
+      );
+      return turn_to_cqqbar(strange_allowed, ran);
     }
-
-    std::size_t const nchannels = channels.count();
-    // no subleading
-    if(nchannels==0) return;
-    if(ran.flat() >= chance){
-      weight_ /= 1 - chance;
-      return;
+    case subleading::extremal_qqbar: {
+      bool const strange_allowed = allow_strange(
+        begin_partons(),
+        end_partons(),
+        proc
+      );
+      return turn_to_eqqbar(strange_allowed, ran);
     }
-    weight_ /= chance;
-
-    // select channel
-    return turn_to_subl( channels, can_be_uno_backward, can_be_uno_forward,
-      allow_strange, ran);
+    default:;
+    }
+    throw std::logic_error{"enum value not covered"};
   }
 
   void PhaseSpacePoint::turn_to_uno(
       const bool can_be_uno_backward, const bool can_be_uno_forward,
       HEJ::RNG & ran
   ){
-    if(!can_be_uno_backward && !can_be_uno_forward) return;
     if(can_be_uno_backward && can_be_uno_forward){
       weight_ *= 2.;
       if(ran.flat() < 0.5){
         return std::swap(begin_partons()->type, std::next(begin_partons())->type);
       }
       return std::swap(rbegin_partons()->type, std::next(rbegin_partons())->type);
     }
     if(can_be_uno_backward){
       return std::swap(begin_partons()->type, std::next(begin_partons())->type);
     }
     assert(can_be_uno_forward);
     std::swap(rbegin_partons()->type, std::next(rbegin_partons())->type);
   }
 
   //! select flavour of quark
   HEJ::ParticleID PhaseSpacePoint::select_qqbar_flavour(
       const bool allow_strange, HEJ::RNG & ran
   ){
     const double r1 = 2.*ran.flat()-1.;
     const double max_flavour = allow_strange?HEJ::N_F:HEJ::N_F-1;
     weight_ *= max_flavour*2;
     double const flavour = HEJ::pid::down + std::floor(std::abs(r1)*max_flavour);
     return static_cast<HEJ::ParticleID>(flavour*(r1<0.?-1:1));
   }
 
   void PhaseSpacePoint::turn_to_cqqbar(const bool allow_strange, HEJ::RNG & ran){
     // we assume all FKL partons to be gluons
     auto first = std::next(begin_partons());
     auto last  = std::next(rbegin_partons());
     auto const ng = std::distance(first, last.base());
     if(ng < 2)
       throw std::logic_error("not enough gluons to create qqbar");
     auto flavour = select_qqbar_flavour(allow_strange, ran);
     // select gluon for switch
     if(ng!=2){
       const double steps = 1./(ng-1.);
       weight_ /= steps;
       for(auto rnd = ran.flat(); rnd>steps; ++first){
         rnd-=steps;
       }
     }
     first->type = flavour;
     std::next(first)->type = anti(flavour);
   }
 
   void PhaseSpacePoint::turn_to_eqqbar(const bool allow_strange, HEJ::RNG & ran){
     /// find first and last gluon in FKL chain
     auto first  = begin_partons();
     const bool can_forward = !is_anyquark(*first);
     auto last = rbegin_partons();
     const bool can_backward = !is_anyquark(*last);
     if(std::distance(first, last.base()) < 2)
       throw std::logic_error("not enough gluons to create qqbar");
     auto flavour = select_qqbar_flavour(allow_strange, ran);
     // select gluon for switch
     if(can_forward && !can_backward){
       first->type = flavour;
       std::next(first)->type = anti(flavour);
       return;
     }
     if(!can_forward && can_backward){
       last->type = flavour;
       std::next(last)->type = anti(flavour);
       return;
     }
     assert(can_forward && can_backward);
     weight_*=2.;
     if(ran.flat()>0.5){
       first->type = flavour;
       std::next(first)->type = anti(flavour);
       return;
     }
     last->type = flavour;
     std::next(last)->type = anti(flavour);
   }
 
   template<class ParticleMomenta>
   fastjet::PseudoJet PhaseSpacePoint::gen_last_momentum(
       ParticleMomenta const & other_momenta,
       const double mass_square, const double y
   ) const {
     std::array<double,2> pt{0.,0.};
     for (auto const & p: other_momenta) {
       pt[0]-= p.px();
       pt[1]-= p.py();
     }
 
     const double mperp = std::sqrt(pt[0]*pt[0]+pt[1]*pt[1]+mass_square);
     const double pz=mperp*std::sinh(y);
     const double E=mperp*std::cosh(y);
 
     return {pt[0], pt[1], pz, E};
   }
 
   Decay PhaseSpacePoint::select_decay_channel(
       std::vector<Decay> const & decays,
       HEJ::RNG & ran
   ){
     double br_total = 0.;
     for(auto const & decay: decays) br_total += decay.branching_ratio;
     // adjust weight
     // this is given by (channel branching ratio)/(chance to pick channel)
     // where (chance to pick channel) =
     //       (channel branching ratio)/(total branching ratio)
     weight_ *= br_total;
     if(decays.size()==1) return decays.front();
     const double r1 = br_total*ran.flat();
     double br_sum = 0.;
     for(auto const & decay: decays){
       br_sum += decay.branching_ratio;
       if(r1 < br_sum) return decay;
     }
     throw std::logic_error{"unreachable"};
   }
   namespace {
     //! generate decay products of a boson
     std::vector<HEJ::Particle> decay_boson(
         HEJ::Particle const & parent,
         std::vector<HEJ::ParticleID> const & decays,
         HEJ::RNG & ran
     ){
       if(decays.size() != 2){
         throw HEJ::not_implemented{
           "only decays into two particles are implemented"
         };
       }
       std::vector<HEJ::Particle> decay_products(decays.size());
       for(size_t i = 0; i < decays.size(); ++i){
         decay_products[i].type = decays[i];
       }
       // choose polar and azimuth angle in parent rest frame
       const double E = parent.m()/2;
       const double theta = 2.*M_PI*ran.flat();
       const double cos_phi = 2.*ran.flat()-1.;   // Jacobian Factors for W in line 418
       const double sin_phi = std::sqrt(1. - cos_phi*cos_phi);  // Know 0 < phi < pi
       const double px = E*std::cos(theta)*sin_phi;
       const double py = E*std::sin(theta)*sin_phi;
       const double pz = E*cos_phi;
       decay_products[0].p.reset(px, py, pz, E);
       decay_products[1].p.reset(-px, -py, -pz, E);
       for(auto & particle: decay_products) particle.p.boost(parent.p);
       return decay_products;
     }
   } // namespace
 
   std::vector<HEJ::Particle> PhaseSpacePoint::decay_channel(
       HEJ::Particle const & parent,
       std::vector<Decay> const & decays,
       HEJ::RNG & ran
   ){
     const auto channel = select_decay_channel(decays, ran);
     return decay_boson(parent, channel.products, ran);
   }
 
   namespace {
     //! adds a particle to target (in correct rapidity ordering)
     //! @returns    positon of insertion
     auto insert_particle(std::vector<HEJ::Particle> & target,
       HEJ::Particle && particle
     ){
       const auto pos = std::upper_bound(
           begin(target),end(target),particle,HEJ::rapidity_less{}
       );
       target.insert(pos, std::move(particle));
       return pos;
     }
   } // namespace
 
   PhaseSpacePoint::PhaseSpacePoint(
     Process const & proc,
     JetParameters const & jet_param,
     HEJ::PDF & pdf, double E_beam,
     double const subl_chance,
-    Subleading subl_channels,
+    Subleading const subl_channels,
     ParticlesDecayMap const & particle_decays,
     HEJ::EWConstants const & ew_parameters,
     HEJ::RNG & ran
   ){
     assert(proc.njets >= 2);
     status_ = Status::good;
     weight_ = 1;
 
     // ensure that all setting are consistent
-    if(subl_chance == 0.)
-      subl_channels.reset();
+    // a more thorough check is in EventGenerator
+    assert(subl_chance > 0. || subl_channels.none());
 
     const std::size_t nout = proc.njets + (proc.boson?1:0)
                               + proc.boson_decay.size();
     outgoing_.reserve(nout);
 
     // generate parton momenta
     const bool is_pure_jets = (nout == proc.njets);
     auto partons = gen_LO_partons(
         proc.njets, is_pure_jets, jet_param, E_beam, ran
     );
+    if(status_ != Status::good) return;
     // pre fill flavour with gluons
-    for( auto it = std::make_move_iterator(partons.begin());
-              it != std::make_move_iterator(partons.end());
-            ++it
-    ){
-      outgoing_.emplace_back(HEJ::Particle{HEJ::pid::gluon, *it, {}});
+    for(auto && parton: std::move(partons)){
+      outgoing_.emplace_back(HEJ::Particle{HEJ::pid::gluon, std::move(parton), {}});
     }
-    if(status_ != Status::good) return;
+
+    const std::optional<subleading::Channels> channel = select_channel(
+      subl_channels,
+      subl_chance,
+      ran
+    );
 
     if(proc.boson){ // decay boson
       auto const & boson_prop = (*proc.boson == HEJ::pid::Z_photon_mix
                                  ? ew_parameters.prop(HEJ::pid::Z)
                                  : ew_parameters.prop(*proc.boson));
-      auto boson{ gen_boson(*proc.boson, boson_prop.mass, boson_prop.width, ran) };
+      auto boson = gen_boson(
+        *proc.boson, boson_prop.mass, boson_prop.width,
+        proc,
+        channel,
+        ran
+      );
       const auto pos{insert_particle(outgoing_, std::move(boson))};
       const size_t boson_idx = std::distance(begin(outgoing_), pos);
       auto const & boson_decay = particle_decays.find(*proc.boson);
       if( !proc.boson_decay.empty() ){ // decay given in proc
         decays_.emplace(
             boson_idx,
             decay_boson(outgoing_[boson_idx], proc.boson_decay, ran)
         );
       } else if( boson_decay != particle_decays.end()
                 && !boson_decay->second.empty() ){ // decay given explicitly
         decays_.emplace(
             boson_idx,
             decay_channel(outgoing_[boson_idx], boson_decay->second, ran)
         );
       }
     }
     // normalisation of momentum-conserving delta function
     weight_ *= std::pow(2*M_PI, 4);
 
     /** @TODO
      *  uf (jet_param.min_pt) doesn't correspond to our final scale choice.
      *  The HEJ scale generators currently expect a full event as input,
      *  so fixing this is not completely trivial
      */
-    reconstruct_incoming(proc, subl_chance, subl_channels, pdf, E_beam, jet_param.min_pt, ran);
+    reconstruct_incoming(proc, channel, pdf, E_beam, jet_param.min_pt, ran);
     if(status_ != Status::good) return;
     // set outgoing states
     begin_partons()->type = incoming_[0].type;
     rbegin_partons()->type = incoming_[1].type;
 
-    maybe_turn_to_subl(subl_chance, subl_channels, proc, ran);
+    if(channel) turn_to_subl(*channel, proc, ran);
 
     if(proc.boson) couple_boson(*proc.boson, ran);
   }
 
   // pt generation, see eq:pt_sampling in developer manual
   double PhaseSpacePoint::gen_hard_pt(
     const int np , const double ptmin, const double ptmax, const double /* y */,
     HEJ::RNG & ran
   ){
     // heuristic parameter for pt sampling, see eq:pt_par in developer manual
     const double ptpar = ptmin + np/5.;
 
     const double arctan = std::atan((ptmax - ptmin)/ptpar);
     const double xpt = ran.flat();
     const double pt = ptmin + ptpar*std::tan(xpt*arctan);
     const double cosine = std::cos(xpt*arctan);
     weight_ *= pt*ptpar*arctan/(cosine*cosine);
     return pt;
   }
 
   double PhaseSpacePoint::gen_soft_pt(int np, double max_pt, HEJ::RNG & ran) {
     constexpr double ptpar = 4.;
 
     const double r = ran.flat();
     const double pt = max_pt + ptpar/np*std::log(r);
     weight_ *= pt*ptpar/(np*r);
     return pt;
   }
 
   double PhaseSpacePoint::gen_parton_pt(
       int count, JetParameters const & jet_param, double max_pt, double y,
       HEJ::RNG & ran
   ) {
     constexpr double p_small_pt = 0.02;
 
     if(! jet_param.peak_pt) {
        return gen_hard_pt(count, jet_param.min_pt, max_pt, y, ran);
     }
     const double r = ran.flat();
     if(r > p_small_pt) {
       weight_ /= 1. - p_small_pt;
       return gen_hard_pt(count, *jet_param.peak_pt, max_pt, y, ran);
     }
     weight_ /= p_small_pt;
     const double pt =  gen_soft_pt(count, *jet_param.peak_pt, ran);
     if(pt < jet_param.min_pt) {
       weight_=0.0;
       status_ = Status::not_enough_jets;
       return jet_param.min_pt;
     }
     return pt;
   }
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::gen_LO_partons(
       int np, bool is_pure_jets,
       JetParameters const & jet_param,
       double max_pt,
       HEJ::RNG & ran
   ){
     if (np<2) throw std::invalid_argument{"Not enough partons in gen_LO_partons"};
 
     weight_ /= std::pow(16.*std::pow(M_PI,3),np);
     weight_ /= std::tgamma(np+1); //remove rapidity ordering
     std::vector<fastjet::PseudoJet> partons;
     partons.reserve(np);
     for(int i = 0; i < np; ++i){
       const double y = -jet_param.max_y + 2*jet_param.max_y*ran.flat();
       weight_ *= 2*jet_param.max_y;
 
       const bool is_last_parton = i+1 == np;
       if(is_pure_jets && is_last_parton) {
         constexpr double parton_mass_sq = 0.;
         partons.emplace_back(gen_last_momentum(partons, parton_mass_sq, y));
         break;
       }
 
       const double phi = 2*M_PI*ran.flat();
       weight_ *= 2.0*M_PI;
 
       const double pt = gen_parton_pt(np, jet_param, max_pt, y, ran);
       if(weight_ == 0.0) return {};
 
       partons.emplace_back(fastjet::PtYPhiM(pt, y, phi));
       assert(jet_param.min_pt <= partons[i].pt());
       assert(partons[i].pt() <= max_pt+1e-5);
     }
     // Need to check that at LO, the number of jets = number of partons;
     fastjet::ClusterSequence cs(partons, jet_param.def);
     auto cluster_jets=cs.inclusive_jets(jet_param.min_pt);
     if (cluster_jets.size()!=unsigned(np)){
       weight_=0.0;
       status_ = Status::not_enough_jets;
       return {};
     }
 
     std::sort(begin(partons), end(partons), HEJ::rapidity_less{});
 
     return partons;
   }
 
   HEJ::Particle PhaseSpacePoint::gen_boson(
       HEJ::ParticleID bosonid, double mass, double width,
+      Process const & proc,
+      std::optional<subleading::Channels> const channel,
       HEJ::RNG & ran
   ){
     // Usual phase space measure for single particle,
     // see eq:single_particle_phase_space in developer manual
     weight_ /= 16.*std::pow(M_PI, 3);
 
     const double y = (bosonid == HEJ::pid::Higgs)?
-      gen_Higgs_rapidity(ran):
+      gen_Higgs_rapidity(proc, channel, ran):
       gen_V_boson_rapidity(ran);
 
     // off-shell sampling, see eq:breit-wigner-sampling in developer manual
     const double r1 = ran.flat();
     const double s_boson = mass*(
         mass + width*std::tan(M_PI/2.*r1 + (r1-1.)*std::atan(mass/width))
     );
     if(bosonid != HEJ::pid::Higgs){
       // two-particle phase space,
       // compare eq:two_particle_phase_space and eq:one_particle_phase_space
       // in developer manual
       weight_/=M_PI*M_PI*16.;
       // Jacobian, see eq:breit-wigner-sampling_jacobian in developer manual
       weight_*= mass*width*( M_PI+2.*std::atan(mass/width) )
               / ( 1. + std::cos( M_PI*r1 + 2.*(r1-1.)*std::atan(mass/width) ) );
     }
 
     return {
       bosonid,
       gen_last_momentum(outgoing_, s_boson, y),
       {}
     };
   }
 
   double PhaseSpacePoint::gen_Higgs_rapidity(
+    Process const & proc,
+    std::optional<subleading::Channels> const channel,
     HEJ::RNG & ran
   ) {
     constexpr double STDDEV_Y_H = 1.6;
+    if(channel && *channel == subleading::uno) {
+      assert(outgoing().size() >= 3);
+      if(proc.incoming[0] == HEJ::pid::gluon) {
+        // backward uno not possible
+        // Higgs has to be before the second most forward parton
+        assert(proc.incoming[1] != HEJ::pid::gluon);
+        return random_normal_trunc(
+          STDDEV_Y_H,
+          ran,
+          std::numeric_limits<double>::lowest(),
+          outgoing_[outgoing().size() - 2].rapidity()
+        );
+      }
+      if(proc.incoming[1] == HEJ::pid::gluon) {
+        // forward uno not possible
+        // Higgs has to be after the second most backward parton
+        assert(proc.incoming[0] != HEJ::pid::gluon);
+        return random_normal_trunc(
+          STDDEV_Y_H,
+          ran,
+          outgoing_[1].rapidity(),
+          std::numeric_limits<double>::max()
+        );
+      }
+    }
     return random_normal(STDDEV_Y_H, ran);
   }
 
   double PhaseSpacePoint::gen_V_boson_rapidity(
       HEJ::RNG & ran
   ){
     // two Gaussians around (+/-)2.6 of std width ~1.8
     const int backward = int (2*ran.flat()); //0:forward 1:backward
     // This is not an integral over two distributions, but a random choice of
     // which option to take, each one representing the full integral.
     // So the weight of the integral should not be multiplied by 2
     constexpr double STDDEV_Y_V = 1.8;
     const double y = random_normal(STDDEV_Y_V, ran);
     return y + (1.-2.*backward)*2.6; // add or subtract 2.6
   }
 
   namespace {
     /// partons are ordered: even = anti, 0 = gluon
-    HEJ::ParticleID index_to_pid(size_t i){
+    constexpr HEJ::ParticleID index_to_pid(size_t i){
       if(!i) return HEJ::pid::gluon;
       return static_cast<HEJ::ParticleID>( i%2 ? (i+1)/2 : -i/2 );
     }
 
     /// partons are ordered: even = anti, 0 = gluon
-    size_t pid_to_index(HEJ::ParticleID id){
+    constexpr size_t pid_to_index(HEJ::ParticleID id){
       if(id==HEJ::pid::gluon) return 0;
       return id>0 ? id*2-1 : std::abs(id)*2;
     }
 
+    constexpr PhaseSpacePoint::part_mask GLUON = 1u << pid_to_index(HEJ::pid::gluon);
+    constexpr PhaseSpacePoint::part_mask ALL = ~0;
+
     PhaseSpacePoint::part_mask init_allowed(HEJ::ParticleID const id){
       if(std::abs(id) == HEJ::pid::proton)
-        return ~0;
+        return ALL;
       PhaseSpacePoint::part_mask out{0};
       if(HEJ::is_parton(id))
         out[pid_to_index(id)] = true;
       return out;
     }
 
     /// decides which "index" (see index_to_pid) are allowed for process
     PhaseSpacePoint::part_mask allowed_quarks(HEJ::ParticleID const boson){
       if(std::abs(boson) != HEJ::pid::Wp){
-        return ~1; // not a gluon
+        return ~GLUON;
       }
       // special case W:
       // Wp: anti-down or up-type quark, no b/t
       // Wm: down or anti-up-type quark, no b/t
       return boson>0?0b00011001100  // NOLINT(readability-magic-numbers)
                     :0b00100110010; // NOLINT(readability-magic-numbers)
     }
   } // namespace
 
   std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_AWZ(
-      Process const & proc, Subleading const subl_channels,
+      Process const & proc,
       std::array<part_mask,2> allowed_partons,
       HEJ::RNG & ran
   ){
     assert(proc.boson);
     auto couple_parton = allowed_quarks(*proc.boson);
-    // eqqbar possible if one incoming is a gluon
-    if(proc.njets >= 3 && subl_channels[subleading::eqqbar]){
-      couple_parton.set(pid_to_index(HEJ::ParticleID::gluon));
-    }
     if( // coupling possible through input
            allowed_partons[0] == (couple_parton&allowed_partons[0])
         || allowed_partons[1] == (couple_parton&allowed_partons[1])
-        // cqqbar possible
-        || (proc.njets >= 4 && subl_channels[subleading::cqqbar])
     ){
       return allowed_partons;
     }
     // only first can couple
     if( (allowed_partons[0]&couple_parton).any()
       &&(allowed_partons[1]&couple_parton).none()
     ){
       return {allowed_partons[0]&couple_parton, allowed_partons[1]};
     }
     // only second can couple
     if(  (allowed_partons[0]&couple_parton).none()
       && (allowed_partons[1]&couple_parton).any()
     ){
       return {allowed_partons[0], allowed_partons[1]&couple_parton};
     }
     // both can couple
     if(  (allowed_partons[0]&couple_parton).any()
       && (allowed_partons[1]&couple_parton).any()
     ){
       double rnd = ran.flat();
       weight_*=3.;
       if(rnd<1./3.){
         return {
           allowed_partons[0] & couple_parton,
           allowed_partons[1] & ~couple_parton
         };
       }
       if(rnd<2./3.){
         return {
           allowed_partons[0] & ~couple_parton,
           allowed_partons[1] & couple_parton
         };
       }
       return {
         allowed_partons[0] & couple_parton,
         allowed_partons[1] & couple_parton
       };
     }
     throw std::invalid_argument{"Incoming state not allowed."};
   }
 
   std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_eqqbar(
       std::array<part_mask,2> allowed_partons, HEJ::RNG & ran
   ){
     auto const gluon_idx = pid_to_index(HEJ::pid::gluon);
     auto & first_beam = allowed_partons[0];
     auto & second_beam = allowed_partons[1];
     if(first_beam[gluon_idx] && !second_beam[gluon_idx]){
       first_beam.reset();
       first_beam.set(gluon_idx);
       return allowed_partons;
     }
     if(!first_beam[gluon_idx] && second_beam[gluon_idx]) {
       second_beam.reset();
       second_beam.set(gluon_idx);
       return allowed_partons;
     }
     if(first_beam[gluon_idx] && second_beam[gluon_idx]) {
       // both beams can be gluons
       // if one can't be a quark everything is good
       auto first_quarks = first_beam;
       first_quarks.reset(gluon_idx);
       auto second_quarks = second_beam;
       second_quarks.reset(gluon_idx);
       if(first_quarks.none() || second_quarks.none()){
         return allowed_partons;
       }
       // else choose one to be a gluon
       double rnd = ran.flat();
       weight_*=3.;
       if(rnd<1./3.){
         allowed_partons[0].reset();
         allowed_partons[0].set(gluon_idx);
         allowed_partons[1].reset(gluon_idx);
       } else if(rnd<2./3.){
         allowed_partons[1].reset();
         allowed_partons[1].set(gluon_idx);
         allowed_partons[0].reset(gluon_idx);
       } else {
         allowed_partons[0].reset();
         allowed_partons[0].set(gluon_idx);
         allowed_partons[1].reset();
         allowed_partons[1].set(gluon_idx);
       }
       return allowed_partons;
     }
     throw std::invalid_argument{
       "Incoming state not allowed for pure extremal qqbar."};
   }
 
   std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_uno(
       std::array<part_mask,2> allowed_partons, HEJ::RNG & ran
   ){
     auto const gluon_idx = pid_to_index(HEJ::pid::gluon);
     auto & first_beam = allowed_partons[0];
+    auto & second_beam = allowed_partons[1];
+    // cannot have Higgs on same side as uno
+    if(outgoing_[0].type == HEJ::pid::Higgs || outgoing_[1].type == HEJ::pid::Higgs) {
+      assert(outgoing().size() >= 4);
+      second_beam.reset(gluon_idx);
+      assert(second_beam.any());
+    } else if(
+      outgoing_.back().type == HEJ::pid::Higgs
+      || outgoing_[outgoing_.size() - 2].type == HEJ::pid::Higgs
+    ) {
+      assert(outgoing().size() >= 4);
+      first_beam.reset(gluon_idx);
+      assert(first_beam.any());
+    }
     auto first_quarks = first_beam;
     first_quarks.reset(gluon_idx);
-    auto & second_beam = allowed_partons[1];
     auto second_quarks = second_beam;
     second_quarks.reset(gluon_idx);
     if(first_quarks.any() && second_quarks.none()){
       first_beam.reset(gluon_idx);
       return allowed_partons;
     }
     if(first_quarks.none() && second_quarks.any()) {
       second_beam.reset(gluon_idx);
       return allowed_partons;
     }
      if(first_quarks.any() && second_quarks.any()) {
       // both beams can be quarks
       // if one can't be gluon everything is good
       if(!first_beam[gluon_idx] || !second_beam[gluon_idx]){
         return allowed_partons;
       }
       // else choose one to be a quark
       double rnd = ran.flat();
       weight_*=3.;
       if(rnd<1./3.){
         allowed_partons[0].reset(gluon_idx);
         allowed_partons[1].reset();
         allowed_partons[1].set(gluon_idx);
       } else if(rnd<2./3.){
         allowed_partons[1].reset(gluon_idx);
         allowed_partons[0].reset();
         allowed_partons[0].set(gluon_idx);
       } else {
         allowed_partons[0].reset(gluon_idx);
         allowed_partons[1].reset(gluon_idx);
       }
       return allowed_partons;
     }
     throw std::invalid_argument{
       "Incoming state not allowed for pure unordered."};
   }
 
   /**
    * @brief Returns list of all allowed initial states partons
    *
    * checks which partons are allowed as initial state:
    * 1. only allow what is given in the Runcard (p -> all)
    * 2. A/W/Z require something to couple to
    *  a) no qqbar => no incoming gluon
    *  b) 2j     => no incoming gluon
    *  c) >3j    => can couple OR is gluon => 2 gluons become qqbar later
    * 3. pure eqqbar requires at least one gluon
    * 4. pure uno requires at least one quark
    */
   std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::allowed_incoming(
       Process const & proc,
-      double const subl_chance, Subleading const subl_channels,
+      std::optional<subleading::Channels> channel,
       HEJ::RNG & ran
   ){
     // all possible incoming states
     std::array<part_mask,2> allowed_partons{
         init_allowed(proc.incoming[0]),
         init_allowed(proc.incoming[1])
       };
-    // special case A/W/Z
-    if(proc.boson && is_AWZ_proccess(proc)){
-      allowed_partons = incoming_AWZ(proc, subl_channels, allowed_partons, ran);
+    // special case: A/W/Z without qqbar
+    if(
+      is_AWZ_proccess(proc)
+      && (!channel || *channel == subleading::unordered)
+    ) {
+      return incoming_AWZ(proc, allowed_partons, ran);
     }
-    // special case: pure subleading
-    if(subl_chance!=1.){
+    if(!channel) return allowed_partons;
+    switch(*channel) {
+    case subleading::central_qqbar:
       return allowed_partons;
-    }
-    auto other_channels = subl_channels;
-    // pure eqqbar
-    other_channels.reset(subleading::eqqbar);
-    if(other_channels.none()){
+    case subleading::extremal_qqbar:
       return incoming_eqqbar(allowed_partons, ran);
-    }
-    other_channels = subl_channels;
-    // pure uno
-    other_channels.reset(subleading::uno);
-    if(other_channels.none()){
+    case subleading::unordered:
       return incoming_uno(allowed_partons, ran);
-    }
-    return allowed_partons;
+    default:;
+    };
+    throw std::logic_error{"enum value not covered"};
   }
 
-
   void PhaseSpacePoint::reconstruct_incoming(
       Process const & proc,
-      double const subl_chance, Subleading const subl_channels,
+      std::optional<subleading::Channels> const channel,
       HEJ::PDF & pdf, double E_beam,
       double uf,
       HEJ::RNG & ran
   ){
     std::tie(incoming_[0].p, incoming_[1].p) = incoming_momenta(outgoing_);
     // calculate xa, xb
     const double sqrts=2*E_beam;
     const double xa=(incoming_[0].E()-incoming_[0].pz())/sqrts;
     const double xb=(incoming_[1].E()+incoming_[1].pz())/sqrts;
     // abort if phase space point is outside of collider energy reach
     if (xa>1. || xb>1.){
       weight_=0;
       status_ = Status::too_much_energy;
       return;
     }
     auto const & ids = proc.incoming;
     std::array<part_mask,2> allowed_partons
-      = allowed_incoming(proc, subl_chance, subl_channels, ran);
+      = allowed_incoming(proc, channel, ran);
     for(size_t i = 0; i < 2; ++i){
       if(ids[i] == HEJ::pid::proton || ids[i] == HEJ::pid::p_bar){
       // pick ids according to pdfs
         incoming_[i].type =
           generate_incoming_id(i, i?xb:xa, uf, pdf, allowed_partons[i], ran);
       } else {
         assert(allowed_partons[i][pid_to_index(ids[i])]);
         incoming_[i].type = ids[i];
       }
     }
     assert(momentum_conserved(1e-7));
   }
 
   HEJ::ParticleID PhaseSpacePoint::generate_incoming_id(
       size_t const beam_idx, double const x, double const uf,
       HEJ::PDF & pdf, part_mask allowed_partons, HEJ::RNG & ran
   ){
     std::array<double,NUM_PARTONS> pdf_wt{};
     pdf_wt[0] = allowed_partons[0]?
       std::fabs(pdf.pdfpt(beam_idx,x,uf,HEJ::pid::gluon)):0.;
     double pdftot = pdf_wt[0];
     for(size_t i = 1; i < pdf_wt.size(); ++i){
       pdf_wt[i] = allowed_partons[i]?
         4./9.*std::fabs(pdf.pdfpt(beam_idx,x,uf,index_to_pid(i))):0;
       pdftot += pdf_wt[i];
     }
     const double r1 = pdftot * ran.flat();
     double sum = 0;
     for(size_t i=0; i < pdf_wt.size(); ++i){
       if (r1 < (sum+=pdf_wt[i])){
         weight_*= pdftot/pdf_wt[i];
         return index_to_pid(i);
       }
     }
     std::cerr << "Error in choosing incoming parton: "<<x<<" "<<uf<<" "
       <<sum<<" "<<pdftot<<" "<<r1<<std::endl;
     throw std::logic_error{"Failed to choose parton flavour"};
   }
 
   void PhaseSpacePoint::couple_boson(
     HEJ::ParticleID const boson, HEJ::RNG & ran
   ){
     if(std::abs(boson) != HEJ::pid::Wp) return; // only matters for W
     /// @TODO this could be use to sanity check gamma and Z
 
     // find all possible quarks
     std::vector<PartonIterator> allowed_parts;
     for(auto part_it=begin_partons(); part_it!=end_partons(); ++part_it){
       // Wp -> up OR anti-down, Wm -> anti-up OR down, no bottom
       if ( can_couple_to_W(*part_it, boson) )
         allowed_parts.push_back(part_it);
     }
     if(allowed_parts.empty()){
       throw std::logic_error{"Found no parton for coupling with boson"};
     }
 
     // select one and flip it
     size_t idx = 0;
     if(allowed_parts.size() > 1){
       /// @TODO more efficient sampling
       ///       old code: probability[i] = exp(parton[i].y - W.y)
       idx = std::floor(ran.flat()*allowed_parts.size());
       weight_ *= allowed_parts.size();
     }
     const int W_charge = boson>0?1:-1;
     allowed_parts[idx]->type =
       static_cast<HEJ::ParticleID>( allowed_parts[idx]->type - W_charge );
   }
 
   double PhaseSpacePoint::random_normal( double stddev, HEJ::RNG & ran ){
     const double r1 = ran.flat();
     const double r2 = ran.flat();
     const double lninvr1 = -std::log(r1);
     const double result = stddev*std::sqrt(2.*lninvr1)*std::cos(2.*M_PI*r2);
     weight_ *= exp(result*result/(2*stddev*stddev))*std::sqrt(2.*M_PI)*stddev;
     return result;
   }
 
+  double PhaseSpacePoint::random_normal_trunc(
+    const double stddev,
+    HEJ::RNG & ran,
+    const double min,
+    const double max
+  ) {
+    double result;
+    std::uint64_t trials = 0;
+    do {
+      ++trials;
+      const double r1 = ran.flat();
+      const double r2 = ran.flat();
+      const double lninvr1 = -std::log(r1);
+      result = stddev*std::sqrt(2.*lninvr1)*std::cos(2.*M_PI*r2);
+    } while(result < min || result > max);
+    weight_ *= exp(result*result/(2*stddev*stddev))*std::sqrt(2.*M_PI)*stddev / trials;
+    return result;
+  }
+
   bool PhaseSpacePoint::momentum_conserved(double ep) const{
     fastjet::PseudoJet diff;
     for(auto const & in: incoming()) diff += in.p;
     for(auto const & out: outgoing()) diff -= out.p;
     return HEJ::nearby_ep(diff, fastjet::PseudoJet{}, ep);
   }
 
+  std::optional<subleading::Channels> PhaseSpacePoint::select_channel(
+    Subleading const subl_channels,
+    double const chance,
+    HEJ::RNG & ran
+  ) {
+    const double r = ran.flat();
+    if(r > chance) {
+      weight_ /= 1 - chance;
+      return {};
+    }
+    // pick a random subleading channel (flat)
+    const std::size_t num_channels = subl_channels.count();
+    weight_ *= num_channels / chance;
+    std::size_t channel_idx = r / chance * num_channels;
+    for(
+      unsigned channel = subleading::first;
+      channel <= subleading::last;
+      ++channel
+    ) {
+      if(subl_channels.test(channel)) {
+        if(channel_idx == 0) {
+          return {static_cast<subleading::Channels>(channel)};
+        } else {
+          --channel_idx;
+        }
+      }
+    }
+    throw std::logic_error{"unreachable"};
+  }
+
 } // namespace HEJFOG
diff --git a/FixedOrderGen/t/W_2j_classify.cc b/FixedOrderGen/t/W_2j_classify.cc
index 7b7ee17..2e0c264 100644
--- a/FixedOrderGen/t/W_2j_classify.cc
+++ b/FixedOrderGen/t/W_2j_classify.cc
@@ -1,163 +1,163 @@
 /**
  * \brief      check that the PSP generates only "valid" W + 2 jets events
  *
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019-2020
  *  \copyright GPLv2 or later
  */
 
 #include <cstdlib>
 #include <iostream>
 #include <string>
 #include <vector>
 
 #include "fastjet/JetDefinition.hh"
 
 #include "HEJ/EWConstants.hh"
 #include "HEJ/exceptions.hh"
 #include "HEJ/Mixmax.hh"
 #include "HEJ/Particle.hh"
 #include "HEJ/PDF.hh"
 #include "HEJ/PDG_codes.hh"
 
 #include "Decay.hh"
 #include "JetParameters.hh"
 #include "PhaseSpacePoint.hh"
 #include "Process.hh"
 #include "Status.hh"
 #include "Subleading.hh"
 
 namespace {
   using namespace HEJFOG;
   using namespace HEJ;
 
   void print_psp(PhaseSpacePoint const & psp){
     std::cerr << "Process:\n"
       << psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
     for(auto const & out: psp.outgoing()){
       std::cerr << out.type << " ";
     }
     std::cerr << "\n";
   }
 
   void bail_out(PhaseSpacePoint const & psp, std::string msg){
     print_psp(psp);
     throw std::logic_error{msg};
   }
 
   bool is_up_type(Particle const & part){
     return HEJ::is_anyquark(part) && !(std::abs(part.type)%2);
   }
   bool is_down_type(Particle const & part){
     return HEJ::is_anyquark(part) && std::abs(part.type)%2;
   }
 
   bool check_W2j(PhaseSpacePoint const & psp, ParticleID const W_type){
     bool found_quark = false;
     bool found_anti = false;
     std::vector<Particle> out_partons;
     std::vector<Particle> Wp;
     for(auto const & p: psp.outgoing()){
       if(p.type == W_type) Wp.push_back(p);
       else if(is_parton(p)) out_partons.push_back(p);
       else bail_out(psp, "Found particle with is not "
             +std::to_string(int(W_type))+" or parton");
     }
     if(Wp.size() != 1 || out_partons.size() != 2){
       bail_out(psp, "Found wrong number of outgoing partons");
     }
     for(std::size_t j=0; j<2; ++j){
       auto const & in = psp.incoming()[j];
       auto const & out = out_partons[j];
       if(is_quark(in) || is_antiquark(in)) {
         found_quark = true;
         if(in.type != out.type) { // switch in quark type -> Wp couples to it
           if(found_anti){ // already found qq for coupling to W
             bail_out(psp, "Found second up/down pair");
           } else if(std::abs(in.type)>4 || std::abs(out.type)>4){
             bail_out(psp, "Found bottom/top pair");
           }
           found_anti = true;
           if( is_up_type(in)) { // "up" in
             if(W_type > 0){
               // -> only allowed u -> Wp + d
               if(in.type < 0 || is_up_type(out) || out.type < 0)
                 bail_out(psp, "u -/> Wp + d");
 
             } else {
               // -> only allowed ux -> Wm + dx
               if(in.type > 0 || is_up_type(out) || out.type > 0)
                 bail_out(psp, "ux -/> Wm + dx");
             }
           } else { // "down" in
             if(W_type > 0){
               // -> only allowed dx -> Wp + ux
               if(in.type > 0 || is_down_type(out) || out.type > 0)
                 bail_out(psp, "dx -/> Wp + ux");
             } else {
               // -> only allowed d -> Wm + u
               if(in.type < 0 || is_down_type(out) || out.type < 0)
                 bail_out(psp, "d -/> Wm + u");
             }
           }
         }
       }
     }
     if(!found_quark) {
       bail_out(psp, "Found no initial quarks");
     } else if(!found_anti){
       bail_out(psp, "Found no up/down pair");
     }
     return true;
   }
 }
 
 int main(){
   constexpr std::size_t n_psp_base = 1337;
   const JetParameters jet_para{
     fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
   PDF pdf(11000, pid::proton, pid::proton);
   constexpr double E_cms = 13000.;
-  constexpr double subl_chance = 0.5;
-  const Subleading subl_channels = subleading::ALL;
+  constexpr double subl_chance = 0.0;
+  const Subleading subl_channels = subleading::NONE;
   const ParticlesDecayMap boson_decays{
       {pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
       {pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
     };
   constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
                                                   {91.187, 2.495},
                                                   {125, 0.004165} };
   HEJ::Mixmax ran{};
 
   // Wp2j
   Process proc {{pid::proton,pid::proton}, 2, pid::Wp, {}};
   std::size_t n_psp = n_psp_base;
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       check_W2j(psp, *proc.boson);
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Wp+2j: Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
   // Wm2j
   proc = Process{{pid::proton,pid::proton}, 2, pid::Wm, {}};
   n_psp = n_psp_base;
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       check_W2j(psp, *proc.boson);
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Wm+2j: Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
 
   std::cout << "All processes passed." << std::endl;
   return EXIT_SUCCESS;
 }
diff --git a/FixedOrderGen/t/W_nj_classify.cc b/FixedOrderGen/t/W_nj_classify.cc
index 44437d8..c6576db 100644
--- a/FixedOrderGen/t/W_nj_classify.cc
+++ b/FixedOrderGen/t/W_nj_classify.cc
@@ -1,226 +1,227 @@
 /**
  *  \brief     check that the PSP generates the all W+jet subleading processes
  *
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019-2020
  *  \copyright GPLv2 or later
  */
 
 #include <algorithm>
 #include <cmath>
 #include <cstdlib>
 #include <iomanip>
 #include <iostream>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "HEJ/Event.hh"
 #include "HEJ/event_types.hh"
 #include "HEJ/EWConstants.hh"
 #include "HEJ/exceptions.hh"
 #include "HEJ/Mixmax.hh"
 #include "HEJ/PDF.hh"
 #include "HEJ/PDG_codes.hh"
 
 #include "fastjet/JetDefinition.hh"
 
 #include "Decay.hh"
 #include "JetParameters.hh"
 #include "PhaseSpacePoint.hh"
 #include "Process.hh"
 #include "Status.hh"
 #include "Subleading.hh"
 
 namespace {
   using namespace HEJFOG;
   using namespace HEJ;
 
   void print_psp(PhaseSpacePoint const & psp){
     std::cerr << "Process:\n"
       << psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
     for(auto const & out: psp.outgoing()){
       std::cerr << out.type << " ";
     }
     std::cerr << "\n";
   }
   void bail_out(PhaseSpacePoint const & psp, std::string msg){
     print_psp(psp);
     throw std::logic_error{msg};
   }
 
   #if !defined(__clang__) && defined(__GNUC__) && (__GNUC__ < 6)
   // gcc version < 6 explicitly needs hash function for enum
   // see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970
   using type_map = std::unordered_map<event_type::EventType, std::size_t, std::hash<std::size_t>>;
   #else
   using type_map = std::unordered_map<event_type::EventType, std::size_t>;
   #endif
 }
 
 int main(){
   constexpr std::size_t n_psp_base = 10375;
   const JetParameters jet_para{
     fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
   PDF pdf(11000, pid::proton, pid::proton);
   constexpr double E_cms = 13000.;
   constexpr double subl_chance = 0.8;
   const ParticlesDecayMap boson_decays{
       {pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
       {pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
     };
   constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
                                                   {91.187, 2.495},
                                                   {125, 0.004165}
   };
   HEJ::Mixmax ran{};
 
   Subleading subl_channels = subleading::ALL;
+  subl_channels.reset(subleading::cqqbar);
   std::vector<event_type::EventType> allowed_types{event_type::FKL,
     event_type::unob, event_type::unof, event_type::qqbar_exb, event_type::qqbar_exf};
 
   std::cout << "Wp3j" << std::endl;
   // Wp3j
   Process proc {{pid::proton,pid::proton}, 3, pid::Wp, {}};
   std::size_t n_psp = n_psp_base;
 
   type_map type_counter;
 
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt) };
       ++type_counter[ev.type()];
       if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
           == allowed_types.cend()) {
         bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
       }
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Wp+3j: Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
   std::cout << "States by classification:\n";
   for(auto const & entry: type_counter){
     const double fraction = static_cast<double>(entry.second)/n_psp_base;
     const int percent = std::round(100*fraction);
     std::cout << std::left << std::setw(25)
               << (name(entry.first) + std::string(":"))
               << entry.second << " (" << percent << "%)\n";
 
   }
   for(auto const & t: allowed_types){
     if(type_counter[t] < 0.05 * n_psp_base){
       std::cerr << "Less than 5% of the events are of type " << name(t) << std::endl;
       return EXIT_FAILURE;
     }
   }
 
   // Wm3j - only uno
   proc = Process{{pid::proton,pid::proton}, 3, pid::Wm, {}};
   n_psp = n_psp_base;
 
   subl_channels.reset();
   subl_channels.set(subleading::uno);
   allowed_types = {event_type::FKL, event_type::unob, event_type::unof};
   type_counter.clear();
 
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt) };
       ++type_counter[ev.type()];
       if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
         == allowed_types.cend()) {
         bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
       }
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Wm+3j (only uno): Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
   std::cout << "States by classification:\n";
   for(auto const & entry: type_counter){
     const double fraction = static_cast<double>(entry.second)/n_psp_base;
     const int percent = std::round(100*fraction);
     std::cout << std::left << std::setw(25)
               << (name(entry.first) + std::string(":"))
               << entry.second << " (" << percent << "%)\n";
 
   }
   for(auto const & t: allowed_types){
     if(type_counter[t] < 0.05 * n_psp_base){
       std::cerr << "Less than 5% of the events are of type " << name(t) << std::endl;
       return EXIT_FAILURE;
     }
   }
 
   // Wm4j
   proc = Process{{pid::proton,pid::proton}, 4, pid::Wm, {}};
   n_psp = n_psp_base;
 
   subl_channels.set();
   allowed_types = {event_type::FKL,
     event_type::unob, event_type::unof, event_type::qqbar_exb, event_type::qqbar_exf,
     event_type::qqbar_mid};
   type_counter.clear();
   std::array<type_map,3> wpos_counter; // position of the W boson (back, central, forward)
 
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt)};
       ++type_counter[ev.type()];
       if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
           == allowed_types.cend()) {
         bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
       }
       if(ev.outgoing().begin()->type==pid::Wm){
         ++wpos_counter[0][ev.type()];
       } else if(ev.outgoing().rbegin()->type==pid::Wm){
         ++wpos_counter[2][ev.type()];
       } else {
         ++wpos_counter[1][ev.type()];
       }
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Wm+4j: Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
   std::cout << "States by classification:\n";
   for(auto const & entry: type_counter){
     const double fraction = static_cast<double>(entry.second)/n_psp_base;
     const int percent = std::round(100*fraction);
     std::cout << std::left << std::setw(25)
               << (name(entry.first) + std::string(":"))
               << entry.second << " (" << percent << "%)\n";
 
   }
   for(auto const & t: allowed_types){
     if(type_counter[t] < 0.03 * n_psp_base){
       std::cerr << "Less than 3% of the events are of type " << name(t) << std::endl;
       return EXIT_FAILURE;
     }
   }
   std::cout << "Stats by Wpos:\n";
   for(std::size_t i=0; i<wpos_counter.size(); ++i){
     std::cout << "position " << i << std::endl;;
     for(auto const & t: allowed_types){
       std::cout <<  name(t) << " " << wpos_counter[i][t] << std::endl;
       if(wpos_counter[i][t] < 0.05 * type_counter[t]){
         std::cerr << "Less than 5% of the events are of type " << name(t)
           << " with W at position " << i << std::endl;
         return EXIT_FAILURE;
       }
     }
   }
 
   std::cout << "All processes passed." << std::endl;
   return EXIT_SUCCESS;
 }
diff --git a/FixedOrderGen/t/Z_2j_classify.cc b/FixedOrderGen/t/Z_2j_classify.cc
index b428a0e..9600e53 100644
--- a/FixedOrderGen/t/Z_2j_classify.cc
+++ b/FixedOrderGen/t/Z_2j_classify.cc
@@ -1,111 +1,111 @@
 /**
  * \brief      check that the PSP generates only "valid" Z + 2 jets events
  *
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019-2020
  *  \copyright GPLv2 or later
  */
 
 #include <cstdlib>
 #include <iostream>
 #include <string>
 #include <vector>
 
 #include "fastjet/JetDefinition.hh"
 
 #include "HEJ/EWConstants.hh"
 #include "HEJ/exceptions.hh"
 #include "HEJ/Mixmax.hh"
 #include "HEJ/Particle.hh"
 #include "HEJ/PDF.hh"
 #include "HEJ/PDG_codes.hh"
 
 #include "Decay.hh"
 #include "JetParameters.hh"
 #include "PhaseSpacePoint.hh"
 #include "Process.hh"
 #include "Status.hh"
 #include "Subleading.hh"
 
 namespace {
   using namespace HEJFOG;
   using namespace HEJ;
 
   void print_psp(PhaseSpacePoint const & psp){
     std::cerr << "Process:\n"
       << psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
     for(auto const & out: psp.outgoing()){
       std::cerr << out.type << " ";
     }
     std::cerr << "\n";
   }
 
   void bail_out(PhaseSpacePoint const & psp, std::string msg){
     print_psp(psp);
     throw std::logic_error{msg};
   }
 
   bool check_Z2j(PhaseSpacePoint const & psp){
     bool found_quark = false;
     std::vector<Particle> out_partons;
     std::vector<Particle> Z;
     for(auto const & p: psp.outgoing()){
       if(p.type == pid::Z_photon_mix) Z.push_back(p);
       else if(is_parton(p)) out_partons.push_back(p);
       else bail_out(psp, "Found particle which is not Z or parton");
     }
     if(Z.size() != 1 || out_partons.size() != 2){
       bail_out(psp, "Found wrong number of outgoing partons");
     }
     for(std::size_t j=0; j<2; ++j){
       auto const & in = psp.incoming()[j];
       auto const & out = out_partons[j];
       if(is_quark(in) || is_antiquark(in)) {
         found_quark = true;
         if(in.type != out.type) {
           bail_out(psp, "Switch in quark type");
         }
       }
     }
     if(!found_quark) {
       bail_out(psp, "Found no initial quark");
     }
     return true;
   }
 }
 
 int main(){
   constexpr std::size_t n_psp_base = 1337;
   const JetParameters jet_para{
     fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
   PDF pdf(11000, pid::proton, pid::proton);
   constexpr double E_cms = 13000.;
-  constexpr double subl_chance = 0.5;
-  const Subleading subl_channels = subleading::ALL;
+  constexpr double subl_chance = 0.0;
+  const Subleading subl_channels = subleading::NONE;
   const ParticlesDecayMap boson_decays{
       {pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
       {pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
     };
   constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
                                                   {91.187, 2.495},
                                                   {125, 0.004165} };
   HEJ::Mixmax ran{};
 
   // Z2j
   Process proc {{pid::proton,pid::proton}, 2, pid::Z_photon_mix, {pid::e_bar,pid::e}};
   std::size_t n_psp = n_psp_base;
   for( std::size_t i = 0; i<n_psp; ++i){
     const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
       boson_decays, ew_constants, ran};
     if(psp.status()==Status::good){
       check_Z2j(psp);
     } else { // bad process -> try again
       ++n_psp;
     }
   }
   std::cout << "Z+2j: Took " << n_psp << " to generate "
     << n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
 
   std::cout << "All processes passed." << std::endl;
   return EXIT_SUCCESS;
 }