diff --git a/FixedOrderGen/src/PhaseSpacePoint.cc b/FixedOrderGen/src/PhaseSpacePoint.cc
index 4ee90cd..ca0009a 100644
--- a/FixedOrderGen/src/PhaseSpacePoint.cc
+++ b/FixedOrderGen/src/PhaseSpacePoint.cc
@@ -1,461 +1,461 @@
 #include "PhaseSpacePoint.hh"
 
 #include <random>
 
 #include <CLHEP/Random/Randomize.h>
 #include <CLHEP/Random/RanluxEngine.h>
 
 #include "HEJ/exceptions.hh"
 #include "HEJ/kinematics.hh"
 #include "HEJ/Particle.hh"
 #include "HEJ/utility.hh"
 
 #include "Process.hh"
 #include "Subleading.hh"
 
 
 using namespace HEJ;
 
 namespace HEJFOG{
 
   static_assert(
       std::numeric_limits<double>::has_quiet_NaN,
       "no quiet NaN for double"
   );
   constexpr double NaN = std::numeric_limits<double>::quiet_NaN();
   HEJ::UnclusteredEvent to_UnclusteredEvent(PhaseSpacePoint const & psp){
     HEJ::UnclusteredEvent result;
     result.incoming = psp.incoming();
     std::sort(
         begin(result.incoming), end(result.incoming),
         [](Particle o1, Particle o2){return o1.p.pz()<o2.p.pz();}
     );
     assert(result.incoming.size() == 2);
     result.outgoing = psp.outgoing();
     assert(
         std::is_sorted(
             begin(result.outgoing), end(result.outgoing),
             HEJ::rapidity_less{}
         )
     );
     assert(result.outgoing.size() >= 2);
     result.decays = psp.decays();
     result.central.mur = NaN;
     result.central.muf = NaN;
     result.central.weight = psp.weight();
     return result;
   }
 
   namespace{
     bool can_swap_to_uno(
         HEJ::Particle const & p1, HEJ::Particle const & p2
     ){
       return is_parton(p1)
         && p1.type != HEJ::pid::gluon
         && p2.type == HEJ::pid::gluon;
     }
   }
 
   void PhaseSpacePoint::maybe_turn_to_uno(
       double chance,
       HEJ::RNG & ran
   ){
     assert(outgoing_.size() >= 2);
     const size_t nout = outgoing_.size();
     const bool can_be_uno_backward = can_swap_to_uno(
         outgoing_[0], outgoing_[1]
     );
     const bool can_be_uno_forward = can_swap_to_uno(
         outgoing_[nout-1], outgoing_[nout-2]
     );
     if(!can_be_uno_backward && !can_be_uno_forward) return;
     if(ran.flat() < chance){
       weight_ /= chance;
       if(can_be_uno_backward && can_be_uno_forward){
         if(ran.flat() < 0.5){
           std::swap(outgoing_[0].type, outgoing_[1].type);
         }
         else{
           std::swap(outgoing_[nout-1].type, outgoing_[nout-2].type);
         }
         weight_ *= 2.;
       }
       else if(can_be_uno_backward){
         std::swap(outgoing_[0].type, outgoing_[1].type);
       }
       else{
         assert(can_be_uno_forward);
         std::swap(outgoing_[nout-1].type, outgoing_[nout-2].type);
       }
     }
     else weight_ /= 1 - chance;
   }
 
   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 = sqrt(pt[0]*pt[0]+pt[1]*pt[1]+mass_square);
     const double pz=mperp*sinh(y);
     const double E=mperp*cosh(y);
 
     return {pt[0], pt[1], pz, E};
   }
 
   PhaseSpacePoint::PhaseSpacePoint(
     Process const & proc,
     JetParameters const & jet_param,
     HEJ::PDF & pdf, double E_beam,
     double subl_change,
     unsigned int subl_channels,
     ParticlesPropMap const & particles_properties,
     HEJ::RNG & ran
   )
   {
     assert(proc.njets >= 2);
     if(proc.boson
       && particles_properties.find(*(proc.boson))
         == particles_properties.end())
       throw HEJ::missing_option("Boson "
         +std::to_string(*(proc.boson))+" can't be generated: missing properties");
     status_ = good;
     weight_ = 1;
 
     const int nout = proc.njets + (proc.boson?1:0);
     outgoing_.reserve(nout);
 
     const bool is_pure_jets = !proc.boson;
     auto partons = gen_LO_partons(
         proc.njets, is_pure_jets, jet_param, E_beam, ran
     );
     for(auto&& p_out: partons) {
-      outgoing_.emplace_back(Particle{pid::gluon, std::move(p_out)});
+      outgoing_.emplace_back(Particle{pid::gluon, std::move(p_out), {}});
     }
     if(status_ != good) return;
 
     // create boson
     if(proc.boson){
       const auto & boson_prop = particles_properties.at(*proc.boson);
       auto boson(gen_boson(*proc.boson, boson_prop.mass, boson_prop.width, ran));
       const auto pos = std::upper_bound(
           begin(outgoing_),end(outgoing_),boson,rapidity_less{}
       );
       outgoing_.insert(pos, std::move(boson));
       if(! boson_prop.decays.empty()){
         const size_t boson_idx = std::distance(begin(outgoing_), pos);
         decays_.emplace(
             boson_idx,
             decay_boson(outgoing_[boson_idx], boson_prop.decays, ran)
         );
       }
     }
     // normalisation of momentum-conserving delta function
     weight_ *= pow(2*M_PI, 4);
 
     reconstruct_incoming(proc.incoming, pdf, E_beam, jet_param.min_pt, ran);
     if(status_ != good) return;
     // set outgoing states
     most_backward_FKL(outgoing_).type = incoming_[0].type;
     most_forward_FKL(outgoing_).type = incoming_[1].type;
 
     if(proc.njets > 2 && subl_channels & Subleading::uno) maybe_turn_to_uno(subl_change, ran);
   }
 
   double PhaseSpacePoint::gen_hard_pt(
       int np , double ptmin, double ptmax, double y,
       HEJ::RNG & ran
   ) {
     // heuristic parameters for pt sampling
     const double ptpar = ptmin + np/5.;
     const double arg_small_y = atan((ptmax - ptmin)/ptpar);
     const double y_cut = 3.;
 
     const double r1 = ran.flat();
     if(y < y_cut){
       const double pt = ptmin + ptpar*tan(r1*arg_small_y);
       const double temp = cos(r1*arg_small_y);
       weight_ *= pt*ptpar*arg_small_y/(temp*temp);
       return pt;
     }
 
     const double ptpar2 = ptpar/(1 + 5*(y-y_cut));
     const double temp = 1. - std::exp((ptmin-ptmax)/ptpar2);
     const double pt = ptmin - ptpar2*std::log(1-r1*temp);
     weight_ *= pt*ptpar2*temp/(1-r1*temp);
     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_ = 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_ /= pow(16.*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_ = not_enough_jets;
       return {};
     }
 
     std::sort(begin(partons), end(partons), rapidity_less{});
 
     return partons;
   }
 
   Particle PhaseSpacePoint::gen_boson(
       HEJ::ParticleID bosonid, double mass, double width,
       HEJ::RNG & ran
   ){
     if(bosonid != HEJ::pid::Higgs)
       throw HEJ::not_implemented("Production of boson "+std::to_string(bosonid)
         +" not implemented yet.");
     // Usual phase space measure
     weight_ /= 16.*pow(M_PI, 3);
 
     // Generate a y Gaussian distributed around 0
     // TODO: magic number only for Higgs
     const double y = random_normal(1.6, ran);
     const double r1 = ran.flat();
     const double sH = mass*(
         mass + width*tan(M_PI/2.*r1 + (r1-1.)*atan(mass/width))
     );
 
     auto p = gen_last_momentum(outgoing_, sH, y);
 
-    return Particle{bosonid, std::move(p)};
+    return Particle{bosonid, std::move(p), {}};
   }
 
   Particle const & PhaseSpacePoint::most_backward_FKL(
       std::vector<Particle> const & partons
   ) const{
     if(!HEJ::is_parton(partons[0])) return partons[1];
     return partons[0];
   }
 
   Particle const & PhaseSpacePoint::most_forward_FKL(
       std::vector<Particle> const & partons
   ) const{
     const size_t last_idx = partons.size() - 1;
     if(!HEJ::is_parton(partons[last_idx])) return partons[last_idx-1];
     return partons[last_idx];
   }
 
   Particle & PhaseSpacePoint::most_backward_FKL(
       std::vector<Particle> & partons
   ) const{
     if(!HEJ::is_parton(partons[0])) return partons[1];
     return partons[0];
   }
 
   Particle & PhaseSpacePoint::most_forward_FKL(
       std::vector<Particle> & partons
   ) const{
     const size_t last_idx = partons.size() - 1;
     if(!HEJ::is_parton(partons[last_idx])) return partons[last_idx-1];
     return partons[last_idx];
   }
 
   void PhaseSpacePoint::reconstruct_incoming(
       std::array<HEJ::ParticleID, 2> const & ids,
       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].p.e()-incoming_[0].p.pz())/sqrts;
     const double xb=(incoming_[1].p.e()+incoming_[1].p.pz())/sqrts;
     // abort if phase space point is outside of collider energy reach
     if (xa>1. || xb>1.){
       weight_=0;
       status_ = too_much_energy;
       return;
     }
     // pick pdfs
     /** @TODO:
      *  ufa, ufb don'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
      */
     for(size_t i = 0; i < 2; ++i){
       if(ids[i] == pid::proton || ids[i] == pid::p_bar){
         incoming_[i].type = generate_incoming_id(i, i?xb:xa, uf, pdf, ran);
       }
       else {
         incoming_[i].type = ids[i];
       }
     }
     assert(momentum_conserved(1e-7));
   }
 
   namespace {
     /// particles are ordered, odd = anti
     ParticleID index_to_pid(size_t i){
       if(!i) return pid::gluon;
       return static_cast<ParticleID>(i%2?(i+1)/2:-i/2);
     }
   }
 
   HEJ::ParticleID PhaseSpacePoint::generate_incoming_id(
       size_t const beam_idx, double const x, double const uf,
       HEJ::PDF & pdf, HEJ::RNG & ran
   ){
     std::array<double,11> pdf_wt;
     pdf_wt[0] = fabs(pdf.pdfpt(beam_idx,x,uf,pid::gluon));
     double pdftot = pdf_wt[0];
       for(size_t i = 1; i < pdf_wt.size(); ++i){
       pdf_wt[i] = 4./9.*fabs(pdf.pdfpt(beam_idx,x,uf,index_to_pid(i)));
       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"};
   }
 
   double PhaseSpacePoint::random_normal(
       double stddev,
       HEJ::RNG & ran
   ){
     const double r1 = ran.flat();
     const double r2 = ran.flat();
     const double lninvr1 = -log(r1);
     const double result = stddev*sqrt(2.*lninvr1)*cos(2.*M_PI*r2);
     weight_ *= exp(result*result/(2*stddev*stddev))*sqrt(2.*M_PI)*stddev;
     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 nearby_ep(diff, fastjet::PseudoJet{}, ep);
   }
 
   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;
     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"};
   }
 
   std::vector<Particle> PhaseSpacePoint::decay_boson(
       HEJ::Particle const & parent,
       std::vector<Decay> const & decays,
       HEJ::RNG & ran
   ){
     const auto channel = select_decay_channel(decays, ran);
     if(channel.products.size() != 2){
       throw HEJ::not_implemented{
         "only decays into two particles are implemented"
       };
     }
     std::vector<Particle> decay_products(channel.products.size());
     for(size_t i = 0; i < channel.products.size(); ++i){
       decay_products[i].type = channel.products[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.;
     const double sin_phi = sqrt(1. - cos_phi*cos_phi);  // Know 0 < phi < pi
     const double px = E*cos(theta)*sin_phi;
     const double py = E*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;
   }
 }
diff --git a/src/PhaseSpacePoint.cc b/src/PhaseSpacePoint.cc
index ea70503..db08408 100644
--- a/src/PhaseSpacePoint.cc
+++ b/src/PhaseSpacePoint.cc
@@ -1,548 +1,548 @@
 /**
  *  \authors   Jeppe Andersen, Tuomas Hapola, Marian Heil, Andreas Maier, Jennifer Smillie
  *  \date      2019
  *  \copyright GPLv2 or later
  */
 #include "HEJ/PhaseSpacePoint.hh"
 
 #include <algorithm>
 #include <assert.h>
 #include <numeric>
 #include <random>
 
 #include "fastjet/ClusterSequence.hh"
 
 #include "HEJ/Constants.hh"
 #include "HEJ/Event.hh"
 #include "HEJ/JetSplitter.hh"
 #include "HEJ/kinematics.hh"
 #include "HEJ/resummation_jet.hh"
 #include "HEJ/utility.hh"
 #include "HEJ/PDG_codes.hh"
 #include "HEJ/event_types.hh"
 
 namespace HEJ{
   namespace {
     constexpr int max_jet_user_idx = PhaseSpacePoint::ng_max;
 
     bool is_nonjet_parton(fastjet::PseudoJet const & parton){
       assert(parton.user_index() != -1);
       return parton.user_index() > max_jet_user_idx;
     }
 
     bool is_jet_parton(fastjet::PseudoJet const & parton){
       assert(parton.user_index() != -1);
       return parton.user_index() <= max_jet_user_idx;
     }
 
     // user indices for partons with extremal rapidity
     constexpr int unob_idx = -5;
     constexpr int unof_idx = -4;
     constexpr int backward_FKL_idx = -3;
     constexpr int forward_FKL_idx = -2;
   }
 
   namespace {
     double estimate_ng_mean(std::vector<fastjet::PseudoJet> const & Born_jets){
       const double delta_y =
         Born_jets.back().rapidity() - Born_jets.front().rapidity();
       assert(delta_y > 0);
       // Formula derived from fit in arXiv:1805.04446 (see Fig. 2)
       return 0.975052*delta_y;
     }
   }
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::cluster_jets(
       std::vector<fastjet::PseudoJet> const & partons
   ) const{
     fastjet::ClusterSequence cs(partons, param_.jet_param.def);
     return cs.inclusive_jets(param_.jet_param.min_pt);
   }
 
   bool PhaseSpacePoint::pass_resummation_cuts(
       std::vector<fastjet::PseudoJet> const & jets
   ) const{
     return cluster_jets(jets).size() == jets.size();
   }
 
   int PhaseSpacePoint::sample_ng(std::vector<fastjet::PseudoJet> const & Born_jets){
     const double ng_mean = estimate_ng_mean(Born_jets);
     std::poisson_distribution<int> dist(ng_mean);
     const int ng = dist(ran_.get());
     assert(ng >= 0);
     assert(ng < ng_max);
     weight_ *= std::tgamma(ng + 1)*std::exp(ng_mean)*std::pow(ng_mean, -ng);
     return ng;
   }
 
   void PhaseSpacePoint::copy_AWZH_boson_from(Event const & event){
     auto const & from = event.outgoing();
 
     const auto AWZH_boson = std::find_if(
         begin(from), end(from),
         [](Particle const & p){ return is_AWZH_boson(p); }
     );
     if(AWZH_boson == end(from)) return;
     auto insertion_point = std::lower_bound(
         begin(outgoing_), end(outgoing_), *AWZH_boson, rapidity_less{}
     );
     outgoing_.insert(insertion_point, *AWZH_boson);
 
     // copy decay products
     const int idx = std::distance(begin(from), AWZH_boson);
     assert(idx >= 0);
     const auto decay_it = event.decays().find(idx);
     if(decay_it != end(event.decays())){
       const int new_idx = std::distance(begin(outgoing_), insertion_point);
       assert(new_idx >= 0);
       assert(outgoing_[new_idx].type == AWZH_boson->type);
       decays_.emplace(new_idx, decay_it->second);
     }
 
     assert(std::is_sorted(begin(outgoing_), end(outgoing_), rapidity_less{}));
   }
 
   PhaseSpacePoint::PhaseSpacePoint(
       Event const & ev, PhaseSpacePointConfig conf, HEJ::RNG & ran
   ):
     unob_{ev.type() == event_type::unob},
     unof_{ev.type() == event_type::unof},
     param_{std::move(conf)},
     ran_{ran}
   {
     weight_ = 1;
     const auto Born_jets = sorted_by_rapidity(ev.jets());
     const int ng = sample_ng(Born_jets);
     weight_ /= std::tgamma(ng + 1);
     const int ng_jets = sample_ng_jets(ng, Born_jets);
     std::vector<fastjet::PseudoJet> out_partons = gen_non_jet(
        ng - ng_jets, CMINPT, param_.jet_param.min_pt
     );
     {
       const auto qperp = std::accumulate(
         begin(out_partons), end(out_partons),
         fastjet::PseudoJet{}
       );
       const auto jets = reshuffle(Born_jets, qperp);
       if(weight_ == 0.) return;
       if(! pass_resummation_cuts(jets)){
        weight_ = 0.;
        return;
       }
       std::vector<fastjet::PseudoJet> jet_partons = split(jets, ng_jets);
       if(weight_ == 0.) return;
       rescale_rapidities(
         out_partons,
         most_backward_FKL(jet_partons).rapidity(),
         most_forward_FKL(jet_partons).rapidity()
       );
       if(! cluster_jets(out_partons).empty()){
         weight_ = 0.;
         return;
       }
       std::sort(begin(out_partons), end(out_partons), rapidity_less{});
       assert(
         std::is_sorted(begin(jet_partons), end(jet_partons), rapidity_less{})
       );
       const auto first_jet_parton = out_partons.insert(
         end(out_partons), begin(jet_partons), end(jet_partons)
       );
       std::inplace_merge(
         begin(out_partons), first_jet_parton, end(out_partons), rapidity_less{}
       );
     }
     if(! jets_ok(Born_jets, out_partons)){
       weight_ = 0.;
       return;
     }
     weight_ *= phase_space_normalisation(Born_jets.size(), out_partons.size());
 
     outgoing_.reserve(out_partons.size() + 1); // one slot for possible A, W, Z, H
     for(auto & p: out_partons){
-      outgoing_.emplace_back(Particle{pid::gluon, std::move(p)});
+      outgoing_.emplace_back(Particle{pid::gluon, std::move(p), {}});
     }
     most_backward_FKL(outgoing_).type = ev.incoming().front().type;
     most_forward_FKL(outgoing_).type = ev.incoming().back().type;
     copy_AWZH_boson_from(ev);
 
     assert(!outgoing_.empty());
     reconstruct_incoming(ev.incoming());
   }
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::gen_non_jet(
       int count, double ptmin, double ptmax
   ){
     // heuristic parameters for pt sampling
     const double ptpar = 1.3 + count/5.;
     const double temp1 = atan((ptmax - ptmin)/ptpar);
 
     std::vector<fastjet::PseudoJet> partons(count);
     for(size_t i = 0; i < (size_t) count; ++i){
       const double r1 = ran_.get().flat();
       const double pt = ptmin + ptpar*tan(r1*temp1);
       const double temp2 = cos(r1*temp1);
       const double phi = 2*M_PI*ran_.get().flat();
       weight_ *= 2.0*M_PI*pt*ptpar*temp1/(temp2*temp2);
       // we don't know the allowed rapidity span yet,
       // set a random value to be rescaled later on
       const double y = ran_.get().flat();
       partons[i].reset_PtYPhiM(pt, y, phi);
       // Set user index higher than any jet-parton index
       // in order to assert that these are not inside jets
       partons[i].set_user_index(i + 1 + ng_max);
 
       assert(ptmin-1e-5 <= partons[i].pt() && partons[i].pt() <= ptmax+1e-5);
     }
     assert(std::all_of(partons.cbegin(), partons.cend(), is_nonjet_parton));
     return partons;
   }
 
   void PhaseSpacePoint::rescale_rapidities(
       std::vector<fastjet::PseudoJet> & partons,
       double ymin, double ymax
   ){
     constexpr double ep = 1e-7;
     for(auto & parton: partons){
       assert(0 <= parton.rapidity() && parton.rapidity() <= 1);
       const double dy = ymax - ymin - 2*ep;
       const double y = ymin + ep + dy*parton.rapidity();
       parton.reset_momentum_PtYPhiM(parton.pt(), y, parton.phi());
       weight_ *= dy;
       assert(ymin <= parton.rapidity() && parton.rapidity() <= ymax);
     }
   }
 
   namespace {
     template<typename T, typename... Rest>
     auto min(T const & a, T const & b, Rest&&... r) {
       using std::min;
       return min(a, min(b, std::forward<Rest>(r)...));
     }
   }
 
   double PhaseSpacePoint::probability_in_jet(
       std::vector<fastjet::PseudoJet> const & Born_jets
   ) const{
     assert(std::is_sorted(begin(Born_jets), end(Born_jets), rapidity_less{}));
     assert(Born_jets.size() >= 2);
 
     const double dy =
       Born_jets.back().rapidity() - Born_jets.front().rapidity();
     const double R = param_.jet_param.def.R();
     const int njets = Born_jets.size();
     const double p_J_y_large = (njets-1)*R*R/(2.*dy);
     const double p_J_y0 = njets*R/M_PI;
     return min(p_J_y_large, p_J_y0, 1.);
   }
 
   int PhaseSpacePoint::sample_ng_jets(
       int ng, std::vector<fastjet::PseudoJet> const & Born_jets
   ){
     const double p_J = probability_in_jet(Born_jets);
     std::binomial_distribution<> bin_dist(ng, p_J);
     const int ng_J = bin_dist(ran_.get());
     weight_ *= std::pow(p_J, -ng_J)*std::pow(1 - p_J, ng_J - ng);
     return ng_J;
   }
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::reshuffle(
       std::vector<fastjet::PseudoJet> const & Born_jets,
       fastjet::PseudoJet const & q
   ){
     if(q == fastjet::PseudoJet{0, 0, 0, 0}) return Born_jets;
     const auto jets = resummation_jet_momenta(Born_jets, q);
     if(jets.empty()){
       weight_ = 0;
       return {};
     }
 
     // additional Jacobian to ensure Born integration over delta gives 1
     weight_ *= resummation_jet_weight(Born_jets, q);
     return jets;
   }
 
   std::vector<int> PhaseSpacePoint::distribute_jet_partons(
       int ng_jets, std::vector<fastjet::PseudoJet> const & jets
   ){
     size_t first_valid_jet = 0;
     size_t num_valid_jets = jets.size();
     const double R_eff = 5./3.*param_.jet_param.def.R();
     // if there is an unordered jet too far away from the FKL jets
     // then extra gluon constituents of the unordered jet would
     // violate the FKL rapidity ordering
     if(unob_ && jets[0].delta_R(jets[1]) > R_eff){
       ++first_valid_jet;
       --num_valid_jets;
     }
     else if(unof_ && jets[jets.size()-1].delta_R(jets[jets.size()-2]) > R_eff){
       --num_valid_jets;
     }
     std::vector<int> np(jets.size(), 1);
     for(int i = 0; i < ng_jets; ++i){
       ++np[first_valid_jet + ran_.get().flat() * num_valid_jets];
     }
     weight_ *= std::pow(num_valid_jets, ng_jets);
     return np;
   }
 
 #ifndef NDEBUG
   namespace{
     bool tagged_FKL_backward(
         std::vector<fastjet::PseudoJet> const & jet_partons
     ){
       return std::find_if(
           begin(jet_partons), end(jet_partons),
           [](fastjet::PseudoJet const & p){
             return p.user_index() == backward_FKL_idx;
           }
       ) != end(jet_partons);
     }
 
     bool tagged_FKL_forward(
         std::vector<fastjet::PseudoJet> const & jet_partons
     ){
       // the most forward FKL parton is most likely near the end of jet_partons;
       // start search from there
       return std::find_if(
           jet_partons.rbegin(), jet_partons.rend(),
           [](fastjet::PseudoJet const & p){
             return p.user_index() == forward_FKL_idx;
           }
       ) != jet_partons.rend();
     }
 
     bool tagged_FKL_extremal(
         std::vector<fastjet::PseudoJet> const & jet_partons
     ){
       return tagged_FKL_backward(jet_partons) && tagged_FKL_forward(jet_partons);
     }
 
   } // namespace anonymous
 #endif
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
       std::vector<fastjet::PseudoJet> const & jets,
       int ng_jets
   ){
     return split(jets, distribute_jet_partons(ng_jets, jets));
   }
 
   bool PhaseSpacePoint::pass_extremal_cuts(
       fastjet::PseudoJet const & ext_parton,
       fastjet::PseudoJet const & jet
   ) const{
     if(ext_parton.pt() < param_.min_extparton_pt) return false;
     return (ext_parton - jet).pt()/jet.pt() < param_.max_ext_soft_pt_fraction;
   }
 
   std::vector<fastjet::PseudoJet> PhaseSpacePoint::split(
       std::vector<fastjet::PseudoJet> const & jets,
       std::vector<int> const & np
   ){
     assert(! jets.empty());
     assert(jets.size() == np.size());
     assert(pass_resummation_cuts(jets));
 
     const size_t most_backward_FKL_idx = 0 + unob_;
     const size_t most_forward_FKL_idx = jets.size() - 1 - unof_;
     const auto & jet = param_.jet_param;
     const JetSplitter jet_splitter{jet.def, jet.min_pt, ran_};
 
     std::vector<fastjet::PseudoJet> jet_partons;
     // randomly distribute jet gluons among jets
     for(size_t i = 0; i < jets.size(); ++i){
       auto split_res = jet_splitter.split(jets[i], np[i]);
       weight_ *= split_res.weight;
       if(weight_ == 0) return {};
       assert(
           std::all_of(
               begin(split_res.constituents), end(split_res.constituents),
               is_jet_parton
           )
       );
       const auto first_new_parton = jet_partons.insert(
           end(jet_partons),
           begin(split_res.constituents), end(split_res.constituents)
       );
       // mark uno and extremal FKL emissions here so we can check
       // their position once all emissions are generated
       auto extremal = end(jet_partons);
       if((unob_ && i == 0) || i == most_backward_FKL_idx){
         // unordered or FKL backward emission
         extremal = std::min_element(
             first_new_parton, end(jet_partons), rapidity_less{}
         );
         extremal->set_user_index(
             (i == most_backward_FKL_idx)?backward_FKL_idx:unob_idx
         );
       }
       else if((unof_ && i == jets.size() - 1) || i == most_forward_FKL_idx){
         // unordered or FKL forward emission
         extremal = std::max_element(
             first_new_parton, end(jet_partons), rapidity_less{}
         );
         extremal->set_user_index(
             (i == most_forward_FKL_idx)?forward_FKL_idx:unof_idx
         );
       }
       if(
           extremal != end(jet_partons)
           && !pass_extremal_cuts(*extremal, jets[i])
       ){
         weight_ = 0;
         return {};
       }
     }
     assert(tagged_FKL_extremal(jet_partons));
     std::sort(begin(jet_partons), end(jet_partons), rapidity_less{});
     if(
         !extremal_ok(jet_partons)
         || !split_preserved_jets(jets, jet_partons)
     ){
       weight_ = 0.;
       return {};
     }
     return jet_partons;
   }
 
   bool PhaseSpacePoint::extremal_ok(
       std::vector<fastjet::PseudoJet> const & partons
   ) const{
     assert(std::is_sorted(begin(partons), end(partons), rapidity_less{}));
     if(unob_ && partons.front().user_index() !=  unob_idx) return false;
     if(unof_ && partons.back().user_index() !=  unof_idx) return false;
     return
       most_backward_FKL(partons).user_index() == backward_FKL_idx
       && most_forward_FKL(partons).user_index() == forward_FKL_idx;
   }
 
   bool PhaseSpacePoint::split_preserved_jets(
         std::vector<fastjet::PseudoJet> const & jets,
         std::vector<fastjet::PseudoJet> const & jet_partons
   ) const{
     assert(std::is_sorted(begin(jets), end(jets), rapidity_less{}));
 
     const auto split_jets = sorted_by_rapidity(cluster_jets(jet_partons));
     // this can happen if two overlapping jets
     // are both split into more than one parton
     if(split_jets.size() != jets.size()) return false;
     for(size_t i = 0; i < split_jets.size(); ++i){
       // this can happen if there are two overlapping jets
       // and a parton is assigned to the "wrong" jet
       if(!nearby_ep(jets[i].rapidity(), split_jets[i].rapidity(), 1e-2)){
         return false;
       }
     }
     return true;
   }
 
   template<class Particle>
   Particle const & PhaseSpacePoint::most_backward_FKL(
       std::vector<Particle> const & partons
   ) const{
     return partons[0 + unob_];
   }
 
   template<class Particle>
   Particle const & PhaseSpacePoint::most_forward_FKL(
       std::vector<Particle> const & partons
   ) const{
     const size_t idx = partons.size() - 1 - unof_;
     assert(idx < partons.size());
     return partons[idx];
   }
 
   template<class Particle>
   Particle & PhaseSpacePoint::most_backward_FKL(
       std::vector<Particle> & partons
   ) const{
     return partons[0 + unob_];
   }
 
   template<class Particle>
   Particle & PhaseSpacePoint::most_forward_FKL(
       std::vector<Particle> & partons
   ) const{
     const size_t idx = partons.size() - 1 - unof_;
     assert(idx < partons.size());
     return partons[idx];
   }
 
   namespace {
     bool contains_idx(
         fastjet::PseudoJet const & jet, fastjet::PseudoJet const & parton
     ){
       auto const & constituents = jet.constituents();
       const int idx = parton.user_index();
       return std::find_if(
           begin(constituents), end(constituents),
           [idx](fastjet::PseudoJet const & con){return con.user_index() == idx;}
       ) != end(constituents);
     }
   }
 
   /**
    * final jet test:
    *   - number of jets must match Born kinematics
    *   - no partons designated as nonjet may end up inside jets
    *   - all other outgoing partons *must* end up inside jets
    *   - the extremal (in rapidity) partons must be inside the extremal jets
    *   - rapidities must be the same (by construction)
    */
   bool PhaseSpacePoint::jets_ok(
       std::vector<fastjet::PseudoJet> const & Born_jets,
       std::vector<fastjet::PseudoJet> const & partons
   ) const{
     fastjet::ClusterSequence cs(partons, param_.jet_param.def);
     const auto jets = sorted_by_rapidity(cs.inclusive_jets(param_.jet_param.min_pt));
     if(jets.size() != Born_jets.size()) return false;
     int in_jet = 0;
     for(size_t i = 0; i < jets.size(); ++i){
       assert(jets[i].has_constituents());
       for(auto && parton: jets[i].constituents()){
         if(is_nonjet_parton(parton)) return false;
       }
       in_jet += jets[i].constituents().size();
     }
     const int expect_in_jet = std::count_if(
         partons.cbegin(), partons.cend(), is_jet_parton
     );
     if(in_jet != expect_in_jet) return false;
     // note that PseudoJet::contains does not work here
     if(! (
            contains_idx(most_backward_FKL(jets), most_backward_FKL(partons))
            &&  contains_idx(most_forward_FKL(jets), most_forward_FKL(partons))
        )) return false;
     if(unob_ && !contains_idx(jets.front(), partons.front())) return false;
     if(unof_ && !contains_idx(jets.back(), partons.back())) return false;
     for(size_t i = 0; i < jets.size(); ++i){
       assert(nearby_ep(jets[i].rapidity(), Born_jets[i].rapidity(), 1e-2));
     }
     return true;
   }
 
   void PhaseSpacePoint::reconstruct_incoming(
       std::array<Particle, 2> const & Born_incoming
   ){
     std::tie(incoming_[0].p, incoming_[1].p) = incoming_momenta(outgoing_);
     for(size_t i = 0; i < incoming_.size(); ++i){
       incoming_[i].type = Born_incoming[i].type;
     }
     assert(momentum_conserved());
   }
 
   double PhaseSpacePoint::phase_space_normalisation(
       int num_Born_jets, int num_out_partons
   ) const{
     return pow(16*pow(M_PI,3), num_Born_jets - num_out_partons);
   }
 
   bool PhaseSpacePoint::momentum_conserved() const{
     fastjet::PseudoJet diff;
     for(auto const & in: incoming()) diff += in.p;
     const double norm = diff.E();
     for(auto const & out: outgoing()) diff -= out.p;
     return nearby(diff, fastjet::PseudoJet{}, norm);
   }
 
 } //namespace HEJ
diff --git a/t/test_descriptions.cc b/t/test_descriptions.cc
index d212ad5..fbd0141 100644
--- a/t/test_descriptions.cc
+++ b/t/test_descriptions.cc
@@ -1,62 +1,62 @@
 #include <iostream>
 #include <cstddef>
 
 #include "HEJ/Event.hh"
 #include "HEJ/EventReweighter.hh"
 #include "HEJ/ScaleFunction.hh"
 
 #define ASSERT(x) if(!(x)) { \
     std::cerr << "Assertion '" #x "' failed.\n"; \
     return EXIT_FAILURE; \
   }
 
 int main() {
   constexpr double mu = 125.;
   HEJ::ScaleFunction fun{"125", HEJ::FixedScale{mu}};
   ASSERT(fun.name() == "125");
 
   HEJ::ScaleGenerator scale_gen{
     {std::move(fun)}, {0.5, 1, 2.}, 2.1
   };
   HEJ::UnclusteredEvent tmp;
   tmp.outgoing.push_back(
-      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(50., -1., 0.3, 0.)}
+      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(50., -1., 0.3, 0.), {}}
   );
   tmp.outgoing.push_back(
-      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(30., 1., -0.3, 0.)}
+      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(30., 1., -0.3, 0.), {}}
   );
   HEJ::Event ev{
     std::move(tmp),
     fastjet::JetDefinition{fastjet::kt_algorithm, 0.4},
     20.
   };
 
   auto rescaled = scale_gen(std::move(ev));
   ASSERT(rescaled.central().description->scale_name == "125");
   for(auto const & var: rescaled.variations()) {
     ASSERT(var.description->scale_name == "125");
   }
   ASSERT(rescaled.central().description->mur_factor == 1.);
   ASSERT(rescaled.central().description->muf_factor == 1.);
 
   ASSERT(rescaled.variations(0).description->mur_factor == 1.);
   ASSERT(rescaled.variations(0).description->muf_factor == 1.);
 
   ASSERT(rescaled.variations(1).description->mur_factor == 0.5);
   ASSERT(rescaled.variations(1).description->muf_factor == 0.5);
 
   ASSERT(rescaled.variations(2).description->mur_factor == 0.5);
   ASSERT(rescaled.variations(2).description->muf_factor == 1.);
 
   ASSERT(rescaled.variations(3).description->mur_factor == 1.);
   ASSERT(rescaled.variations(3).description->muf_factor == 0.5);
 
   ASSERT(rescaled.variations(4).description->mur_factor == 1.);
   ASSERT(rescaled.variations(4).description->muf_factor == 2.);
 
   ASSERT(rescaled.variations(5).description->mur_factor == 2.);
   ASSERT(rescaled.variations(5).description->muf_factor == 1.);
 
   ASSERT(rescaled.variations(6).description->mur_factor == 2.);
   ASSERT(rescaled.variations(6).description->muf_factor == 2.);
 }
diff --git a/t/test_scale_import.cc b/t/test_scale_import.cc
index 7a194c3..a434885 100644
--- a/t/test_scale_import.cc
+++ b/t/test_scale_import.cc
@@ -1,31 +1,31 @@
 #include <stdexcept>
 #include <iostream>
 
 #include "HEJ/YAMLreader.hh"
 #include "HEJ/Event.hh"
 
 int main(int argc, char** argv) {
   constexpr double ep = 1e-7;
   if (argc != 2) {
     throw std::logic_error{"wrong number of args"};
   }
   const HEJ::Config config = HEJ::load_config(argv[1]);
 
   HEJ::UnclusteredEvent tmp;
   tmp.outgoing.push_back(
-      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(50., -1., 0.3, 0.)}
+      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(50., -1., 0.3, 0.), {}}
   );
   tmp.outgoing.push_back(
-      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(30., 1., -0.3, 0.)}
+      {HEJ::ParticleID::gluon, fastjet::PtYPhiM(30., 1., -0.3, 0.), {}}
   );
   HEJ::Event ev{
     std::move(tmp),
     fastjet::JetDefinition{fastjet::kt_algorithm, 0.4},
     20.
   };
 
   const double softest_pt = config.scales.base[0](ev);
   if(std::abs(softest_pt-30.) > ep){
     throw std::logic_error{"wrong softest pt"};
   }
 }