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Herwig News -*- outline -*-
================================================================================
+* Herwig 7.0.3 release: 2016-xx-xx
+
+** fix for relocating MadGraph generated amplitudes
+ The directory and symbolic link structure for MadGraph-built amplitudes has
+ been changed to allow for relocation of a run directory to a different file
+ system hierarchy.
+
+** z* variable added to LeptonsJetsAnalysis
+ The builtin LeptonsJetsAnalysis has been extented to include the normalized
+ relative rapidity z*
+
+** fix to directory hierarchy
+ A bug in the Herwig-scratch directory hierarchy when integrating with
+ different seeds has been fixed.
+
+** detuning parameter for shower reweighting
+ An efficiency tweak when using the shower reweighting facilities has been
+ introduced for the veto algorithms in both the QTilde and the Dipole
+ shower. See the documentation for more details.
+
+** subprocess generation filters
+ A number of filters has been implemented to speed up process and diagram
+ generation for the case of Standard Model like processes; this is
+ particularly helpful for processes involving a large number of electroweak
+ combinatorics. See the documentation for more details.
+
* Herwig 7.0.2 release: 2016-04-29
** Event reweighting
- New option of calculating the weights for the effect of varying the scale used in both the default and dipole showers. This will be described in a forthcoming publication.
+ New option of calculating the weights for the effect of varying the scale
+ used in both the default and dipole showers. The method is described in
+ arXiv:1605.08256
** mergegrids mode
- A main mode for the Herwig executable has been added which merges the integration grids from parallel runs.
+ A main mode for the Herwig executable has been added which merges the
+ integration grids from parallel runs.
** NLO Diphoton production
- The NLO matrix elements in the POWHEG approach for diphoton production as described in JHEP 1202 (2012) 130, arXiv:1106.3939 have been included as MEPP2GammaGammaPowheg.
+ The NLO matrix elements in the POWHEG approach for diphoton production as
+ described in JHEP 1202 (2012) 130, arXiv:1106.3939 have been included as
+ MEPP2GammaGammaPowheg.
** BSM Hard process constructor
- A missing Feynman diagram with a t-channel vector boson has been added to the matrix element for vv2ss
+ A missing Feynman diagram with a t-channel vector boson has been added to
+ the matrix element for vv2ss
** BSM Decay Modes calculation
- The behaviour of the option to disable decay modes in BSM Models has been changed so that the partial width for the ignored modes is now calculated and included in the total width, but the branching ratio is set to zero. This is more physical than the previous option where the mode was totally ignored and hence not included in the calculation of the width.
+ The behaviour of the option to disable decay modes in BSM Models has been
+ changed so that the partial width for the ignored modes is now calculated
+ and included in the total width, but the branching ratio is set to
+ zero. This is more physical than the previous option where the mode was
+ totally ignored and hence not included in the calculation of the width.
** Mass Generation
- The behaviour of the GenericMassGenerator has been changed so that modes which have been disabled are only included in the calculation of the total width and not in the partial width used in the numerator of the weight used to select the off-shell mass.
+ The behaviour of the GenericMassGenerator has been changed so that modes
+ which have been disabled are only included in the calculation of the total
+ width and not in the partial width used in the numerator of the weight used
+ to select the off-shell mass.
** Boost detection
Boost could not detect the compiler version for gcc-5.3 and gcc-6.1
* Herwig 7.0.1 release: 2016-01-17
** Version number written to log file
The Herwig version number is now included in addition to ThePEG's version.
** Tau lifetimes
A bug with lifetimes for hard process Taus is fixed. Thanks to ATLAS
for the report!
** Shower FSR retries
Rare events could take a long time due to an extremely large number
of FSR retries. These are now capped at a configurable number.
** Dipole shower
Reweighting for non-radiating events; fixes for shower profile
handling; option to downgrade large-Q expansion for alphaS
** Matchbox builtins
Added massive currents for q-qbar
** ShowerAlphaQCD
can now use user-defined thresholds
** Input snippets
W/Z/H on-shell now split into three files; 4-flavour scheme added
** UFO converter
The converter now has experimental support for writing out param
cards of its current settings.
** LEPJetAnalysis loading fixed
** Contrib
HJets++ has moved to a stand-alone project, FxFx has been added
* Herwig 7.0.0 (Herwig++ 3.0.0) release: 2015-12-04
** Major new release
A major new release of the Monte Carlo event generator Herwig++ (version
3.0) is now available. This release marks the end of distinguishing
Herwig++ and HERWIG development and therefore constitutes the first major
release of version 7 of the Herwig event generator family. The new version
features a number of significant improvements to the event simulation,
including: built-in NLO hard process calculation for all Standard Model
processes, with matching to both angular ordered and dipole shower modules
via variants of both subtractive (MC@NLO-type) and multiplicative
(Powheg-type) algorithms; QED radiation and spin correlations in the
angular ordered shower; a consistent treatment of perturbative
uncertainties within the hard process and parton showering, as well as a
vastly improved documentation. This version includes (for a more detailed
overview and further references please see the release note
arXiv:1512.01178):
** A long list of improvements and fixes for the Matchbox module
*** includes MC@NLO and Powheg matching to both showers with truncated showering
** A long list of improvements and fixes for both of the shower modules
*** includes improvements of numerics issues relevant to 100 TeV pp collisions
** NLO event simulation and Matchbox development
*** Interfaces to a number of external libraries
*** A new workflow for event generation
*** Electroweak corrections to VV production
** Parton shower development
*** QED radiation in the angular ordered shower
*** Spin correlations in the angular ordered shower
*** New scale choices in gluon branchings
** Improvements to event generation workflow
*** Re-organized and streamlined input files for the new NLO development
*** A unified treatment of shower and matching uncertainties
*** New integrator modules featuring parallel integration
** New default tunes for both shower modules
** New contrib modules
*** Electroweak Higgs plus jets production
*** FxFx merging support
*** Higgs boson pair production
* Herwig++-2.7.1 release: 2014-07-07
** New shower switches to select schemes for momentum reconstruction
*** QTildeReconstructor:FinalStateReconOption
has the following options:
*** Default
All momenta are rescaled in the rest frame.
*** MostOffShell
Put all particles on the new-mass shell and the most off-shell and
recoiling system are rescaled to ensure 4-momentum is conserved.
*** Recursive
Recursively put the most off-shell particle which hasn't yet been
rescaled on-shell by rescaling the particles and the recoiling
system.
*** RestMostOffShell
The most off-shell is put on shell by rescaling it and the
recoiling system, the recoiling system is then put on-shell in its
rest frame.
*** RestRecursive
As above, but recursively treat the currently most-off shell
(only makes a difference for more than 3 partons)
** Ticket #378: Hadronization of baryon number violating clusters involving diquarks
Fixed by only considering non-diquarks to be combined in the
ClusterFinder.
** UFO converter can now parse SLHA files for parameter settings
The UFO converter code can now use SLHA files for modifying
parameters. The first pass "ufo2herwig" produces the model to be
compiled. For each parameter card, run "slha2herwig" to get the
matching input file.
** Fix for systems using lib64
The repository is now initialized correctly on systems using lib64
as the library location.
** Efficiency optimization
Better allocation of internal vector variables for a noticeable
speed increase of 10-20% with LHC events.
* Herwig++-2.7.0 release: 2013-10-28
** UFO interface to Feynman rules generators
Herwig++ now includes "ufo2herwig", a tool that automatically
creates all required files to run a BSM model from a UFO
directory. The conversion has been extensively tested against
Feynrules models MSSM, NMSSM, RS, Technicolor,
and less extensively with most of the
other models in the Feynrules model database.
We expect that following this release there will be no further
hard-coded new physics models added to Herwig++ and that future
models will be included using the UFO interface.
** Shower uncertainties
A first set of scaling parameters to estimate shower uncertainties
is provided for both the angular ordered as well as the dipole
shower; they are Evolver:HardScaleFactor and ShowerAlphaQCD:
RenormalizationScaleFactor.
** Rewrite of Matchbox NLO matching
The NLO matching implementation has been rewritten and is now more
flexible and consistent. Profile scales are provided for the
hardest emission both for the dipole shower and matrix element
correction matching.
** BLHA2 Interface and new processes
Matchbox now features a generic BLHA2 interface to one-loop
amplitude codes and now also includes W and W+jet production as
well as Higss production in gluon fusion as builtin processes.
** Impoved dipole shower kinematics parametrization
The kinematics parametrization for emissions in the dipole shower
has been made more efficient.
** W and Z Powheg decays
Decays of W and Z bosons now use the Powheg decayers by default.
** Improved treatment of beam remnants
The handling of beam remnants has been improved in multiple
contexts, leading to a much lower error rate at p+/p- collisions.
An additional value "VeryHard" for ClusterFissioner:RemnantOption
can be used to disable any special treatment of beam remnant
clusters.
** New underlying event tune
Herwig++ now uses tune UE-EE-5-MRST by default. Other related tunes
can be obtained from the Herwig++ tunes page
** Improvements in BSM code
The UFO development identified many sign fixes in rarely used BSM
vertices; many improvements were made to general decayers, allowing
four-body decays in BSM for the first time; Powheg is enabled in
General two-body decayers; and the handling of colour
sextets has been improved.
** A new HiggsPair matrix element in Contrib.
** A new matrix element for single top production.
** The Higgs mass is now set to 125.9 GeV (from PDG 2013 update).
** C++-11 testing
To help with the coming transition to C++-11, we provide the new
--enable-stdcxx11 configure flag. Please try to test builds with
this flag enabled and let us know any problems, but do not use this
in production code yet. In future releases, this flag will be on by
default.
** Other changes
*** Many new Rivet analyses have been included in the Tests directory.
*** Cleaned Shower header structure; grouped shower parameters into one struct.
*** The boolean Powheg flag in HwMEBase changed to an enumeration.
* Herwig++-2.6.3 release: 2013-02-22
** Decay vertex positioning in HepMC output
Pseudo-vertices that Herwig++ inserts for technical reasons will
now not contribute to the Lorentz positions of downstream vertices.
Thanks to ATLAS for the bug report!
** Updated Rivet tests
Herwig's library of Rivet test runs has been brought up-to-date
with new analyses that were recently published by the Rivet
collaboration.
* Herwig++-2.6.2 release: 2013-01-30
** Fixes for PDF and scale choices in POWHEG events
Scale settings for MPI and the regular shower are now correct in
POWHEG events. This should fix reported anomalies in POWHEG jet rates.
NLO PDFs are now also set consistently in the example input files.
** Ticket #373: Branching ratio factors in cross-section
If any decay modes are selectively disabled, setting the following
post-handler will cause all reported cross-sections to include the
branching ratio factor(s) from the previous stages correctly:
create Herwig::BranchingRatioReweighter BRreweight
insert LHCGenerator:EventHandler:PostDecayHandlers 0 BRreweight
** Anomalous vertices now possible in MEfftoVH
** Interactive shell does not quit on error
** Better warning messages for events from inconsistent LHEF files
** Possible division by zero error fixed in BSM branching ratio calculations
** Decayer and ME changes to improve checkpointing
The checkpointing changes in ThePEG 1.8.2 are implemented here, too. Regular
dump files are consistent now.
* Herwig++-2.6.1 release: 2012-10-16
** Configure switches
The various switches to turn off compilation of BSM models have
been unified into a single '--disable-models'. A new flag
'--disable-dipole' can be used to turn off the compilation of the
Dipole and Matchbox codes.
** Ticket #348: Search path for repository 'read' command
The search path for the 'read' command is configurable on the
command line with the -i and -I switches. By default, the
installation location is now included in the search path, so that
'Herwig++ read LEP.in' will work in an empty directory. The current
working directory will always be searched first.
The rarely used "Herwig++ init" command has been made consistent
with 'read' and 'run' and should now be used without the '-i' flag.
** Width treatment in BSM
The width treatment in BSM decay chains has been greatly improved
and is now switched on by default in the .model files. To get the
old behaviour, use
set /Herwig/NewPhysics/NewModel:WhichOffshell Selected
** New BSM models
Little Higgs models with and without T-parity are now available.
** Resonance photon lifetime
A lifetime bug affecting decays of pi0 to e+e-X was fixed. The
virtual photon is not part of the event record anymore.
** Ticket #371: Hard diffraction FPE
Herwig++ 2.6.0 introduced a bug into the diffraction code which
would abort any runs. This is now fixed.
** O2AlphaS
Support for setting quark masses different from the particle data
objects as introduced in ThePEG 1.8.1 has been enabled.
** Matchbox
Several improvements and bug fixes are included for
Matchbox. Amplitudes relevant to pp -> Z+jet and crossed processes
at NLO are now available, and various scale choices have been added
in a more flexible way. All subtraction dipoles for massive quarks
are now included.
** Dipole shower
Parameters to perform scale variations in the shower have been
added to estimate uncertainties. A bug in showering off gg -> h has
been fixed.
** Minor fixes
*** Two broken colour structures in GeneralHardME
*** Susy Higgs mixing matrix
*** BaryonFactorizedDecayer out-of-bounds access
*** Mass values in SimpleLHCAnalysis
* Herwig++-2.6.0 release: 2012-05-21 (tagged at SVN r7407)
** New NLO framework
Matchbox, a flexible and very general framework for performing NLO
calculations at fixed order or matched to parton showers is
provided with this release.
** Dipole shower algorithm
A first implementation of the coherent dipole shower algorithm by
Plätzer and Gieseke (arXiv:0909.5593 and arXiv:1109.6256) is
available.
** Alternative samplers and the ExSample library
The ExSample library by Plätzer (arXiv:1108.6182) is shipped along
with Herwig++ in an extended version. The extended version provides
SamplerBase objects which can be used alternatively to the default
ACDCSampler.
** New BSM models
*** New colour sextet diquark model
A colour sextet diquark model has been included, as described in
Richardson and Winn (arXiv:1108.6154).
*** Models reproducing the CDF t-tbar asymmetry
Four models that can reproduce the reported t-tbar asymmetry have
been included.
*** Zprime
A simple standard model extension by one additional heavy neutral
vector boson.
** Interface to AlpGen, with MLM merging
The Contrib directory contains a new interface to the AlpGen matrix
element generator. AlpGen events must be preprocessed with the
provided AlpGenToLH.exe tool before they can be used. More
information can be found in the Herwig++ 2.6 release note.
** HiggsVBF Powheg
Higgs boson production by vector boson fusion is available at NLO
in the POWHEG scheme, as described in d'Errico, Richardson
(arXiv:1106.2983). The Powheg DIS processes were available in
Herwig++-2.5.2 already.
** Statistical colour reconnection
Alternative mechanisms to minimize the colour length Sum(m_clu)
before the hadronization stage, based on Metropolis and annealing
algorithms.
** Energy extrapolation of underlying-event tunes
To describe underlying-event data at different c.m. energies, the
energy-dependent parameter pT_min will now be adjusted
automatically, following a power-law. The new tune parameters are
the value at 7000 GeV "MPIHandler:pTmin0", and MPIHandler:Power.
** Ticket #239: Reporting of minimum-bias cross-section
When simulating minimum-bias events using the MEMinBias matrix
element, the correct unitarized cross section can now be reported
via the standard facilities; it is no longer necessary to extract
it from the .log file of the run. The corresponding functionality
is enabled by inserting a MPIXSecReweighter object as a
post-subprocess handler:
create Herwig::MPIXSecReweighter MPIXSecReweighter
insert LHCHandler:PostSubProcessHandlers 0 MPIXSecReweighter
** Dependency on 'boost'
Herwig++ now requires the boost headers to build; if not detected
in standard locations, specify with the --with-boost configure
option.
** Tests directory
The Tests directory now contains input cards for almost all Rivet
analyses. A full comparison run can be initiated with 'make tests'.
** Minor changes
*** Default LHC energy now 8 TeV
All LHC-based defaults have now been updated to use 8 TeV as the
center-of-mass energy.
*** Herwig::ExtraParticleID -> ThePEG::ParticleID
The namespace for additional particles has been unified into
ThePEG::ParticleID
*** MEee2VectorMeson
The e+e- -> vector meson matrix element has moved from Contrib into
HwMELepton.so
*** SUSY numerics fixes
Better handling of rare numerical instabilities.
*** YODA output for Rivet
The built-in histogramming handler can now output data in the YODA
format used by Rivet.
*** Consistency checks in SLHA file reader
Better warnings for inconsistent SusyLHA files
*** better colour flow checking for development
** Bug fixes
*** Extremely offshell W from top decay
Numerical improvements for very off-shell W bosons coming from top
decays.
*** Ticket #367: problems in using SUSY + LHE
Susy events from Les Houches event files are now handled better.
*** Infinite loop in remnant decayer
The remnant decayer will now abort after 100 tries.
*** Fix to HiggsVBF LO diagrams
The diagram structure of HiggsVBF LO matrix elements has been fixed.
*** LEP thrust fix
The calculation of the transverse momentum of a branching from the
evolution variable in final-state radiation can now be
changed. While formally a sub-leading choice this enables a better
description of the thrust distribution in e+e- collisions at
small values of the thrust. Currently the default behaviour, where
the cut-off masses are used in the calculation, remains the same
as previous versions.
* Herwig++-2.5.2 release: 2011-11-01 (tagged at SVN r6928)
** Optional new jet vetoing model
The jet vetoing model by Schofield and Seymour (arXiv:1103.4811) is
available via Evolver:ColourEvolutionMethod,
PartnerFinder:PartnerMethod and SplittingFunction:SplittingColourMethod.
The default behaviour is unchanged.
** MPI tune
Version 3 of the MPI tunes is now the default. Please note that the
pT parameter is energy-dependent and needs to be modified when an
LHC run is not at 7 TeV.
The latest tunes are always available at
http://projects.hepforge.org/herwig/trac/wiki/MB_UE_tunes
** MPI PDFs
MPI PDFs can now be controlled independently.
** Initialization time speedup
A new BSMModel base class was introduced between StandardModel and
the BSM model classes. Together with a restructured decay mode
initialization, this offers significantly faster startup times for
BSM runs. ThreeBodyDecays can now always be switched on without a
large speed penalty.
** Decay mode file
Decay mode files in the SLHA format can now be read separately in
any BSM model with 'set Model:DecayFileName filename'
** Powheg DIS
Charged- and neutral-current DIS processes implementing the POWHEG
method are now available.
** Diffraction models
Xi cut implemented in PomeronFlux
** Ticket #352: Colour reconnection fixed in DIS
** Ticket #353: Improved numerical stability in chargino decays
** Ticket #358: Infinite loop in top events with pT cut in shower
** Ticket #361: Problem with duplicate 2-body modes in BSM
** Tickets #362 / #363: Crashes with baryon number violating models
Particle decays in SUSY models with RPV now work correctly in the
colour 8 -> 3,3,3 case. Colour reshuffling now works for RPV
clusters.
** Improved Fastjet detection
The configure step uses fastjet-config to make sure all header file
paths are seen.
** Darwin 11 / OS X Lion
A configure bug was fixed which prevented 'make check' from
succeeding on OS X Lion.
** Vertex classes
The specification of QED / QCD orders has been moved to the vertex
constructors, to allow ThePEG consistency checks. WWHH vertices in
MSSM and NMSSM were fixed. Some Leptoquark and UED vertices fixed.
** Hadronization
Cleanup of obsolete code.
* Herwig++-2.5.1 release: 2011-06-24 (tagged at SVN r6609)
** Example input files at 7 TeV
All our example input files for LHC now have their beam energy set
to 7 TeV instead of 14 TeV.
** Colour reconnection on by default
The colour reconnection tunes are now the default setup. Version 2
of the tunes replaces the *-1 tunes, which had a problem with LEP
event shapes.
** Run name tags
Aded possibility to add a tag to the run name when running with the
'-t' option. One run file can thus be run with different seeds and
results stored in different output files.
** Floating point exceptions
The new command line option -D enables floating point error checking.
** General improvements to WeakCurrent decays
** Remnant decayer
Hardwired gluon mass was removed.
** WeakCurrentDecayConstructor
Instead of specifying separate Particle1...Particle5 vectors for
the decay modes, the new interface DecayModes can be filled with
decay tags in the standard syntax.
** BSM: improvements to handling of vertex and model initialisation
** Powheg Higgs
Option to use pT or mT as the scale in alphaS and for the
factorization scale in the PDFs
** Ticket #337: Tau polarization wrong in charged Higgs decay
** Ticket #339: Colour flows in GeneralThreeBody Decayers for 3bar -> 8 3bar 1
** Ticket #340: Crash for resonant zero-width particles
** Ticket #341: Varying scale for BSM processes
The scale used is now ResonantProcessConstructor:ScaleFactor or
TwoToTwoProcessConstructor:ScaleFactor multiplied by sHat.
** Ticket #346: Chargino decays
Chargino decayers now automatically switch between the mesonic
decays for mass differences less than 2 GeV and the normal partonic
decays above 2 GeV.
** Ticket #349: Stop by default on input file errors
The '--exitonerror' flag is now the default behaviour for the
Herwig++ binary. To switch back to the old behaviour,
'--noexitonerror' is required.
** Ticket #351: Four-body stop decays
** Tested with gcc-4.6
* Herwig++-2.5.0 release: 2011-02-08 (tagged at SVN r6274)
** Uses ThePEG-1.7.0
Herwig++ 2.5.0 requires ThePEG 1.7.0 to benefit from various
improvements, particularly: handling of diffractive processes;
respecting LD_LIBRARY_PATH when loading dynamic libraries,
including LHAPDF; improvements to repository commands for decay
modes. See ThePEG's NEWS file for more details.
** POWHEG improvements
*** New POWHEG processes
Simulation at NLO accuracy using the POWHEG method is now
available for hadronic diboson production (pp to WW,WZ,ZZ), Higgs
decays to heavy quarks, and e+e- to two jets or ttbar, including
full mass dependence.
*** Input file changes
The input files for setting up POWHEG process simulation have been
simplified. See the example files LHC-Powheg.in and TVT-Powheg.in
for the improved command list.
*** Structural changes
The POWHEG backend in the shower code has been restructured to
make future additions easier: PowhegEvolver has merged with
Evolver; both the matrix element corrections and real corrections
in the POWHEG scheme are implemented directly in the ME or Decayer
classes.
** New processes at leading order
*** Photon initiated processes
We have added a matrix element for dijet production in gamma
hadron collisions.
*** Bottom and charm in heavy quark ME
The option of bottom and charm quarks is now supported for heavy
quark production in MEHeavyQuark.
** Colour reconnection
The cluster hadronization model has been extended by an option to
reconnect coloured constituents between clusters with a given
probability. This new model is different from the colour
reconnection model used in FORTRAN HERWIG, and improves the
description of minimum bias and underlying event data.
** Diffractive Processes
Both single and double diffractive processes are now supported in
Herwig++. The Pomeron PDF is implemented using a fit to HERA data,
and a pion PDF can be used to model reggeon flux.
** BSM physics
*** New models
We have added new BSM models, particularly ADD-type extra
dimension models and the next-to-minimal supersymmetric standard
model (NMSSM). Effects of leptoquarks can as well be simulated.
*** Vertex additions
We have added flavour changing stop interactions (stop -
neutralino - charm) and gravitino interactions with particular
emphasis on numerical stability for very light gravitinos.
Tri-linear Higgs and Higgs-Higgs/Vector-Vector four-vertices are
available as well.
*** Input file changes
The SUSY model can now also extract the SLHA information from the
header of a Les Houches event file: replace the SLHA file name
in the example input files with the LH file name.
*** Structure
The backend structure of the HardProcessConstructor has changed,
to allow easier inclusion of new process constructors. Some 2->3
BSM scattering processes involving neutral higgs bosons are now
included. The spin handling has been improved in the background.
** Shower splitting code reorganized
The selection of spin structures has been decoupled from the choice
of colour structure. This gives more flexibility in implementing
new splittings. Selected splittings can be disabled in the input
files.
** B mixing
B mixing, and indirect CP violation in the B meson system are
included now.
** Looptools
The Looptools directory has been updated to reflect T.Hahn's
Looptools 2.6.
** Contrib changes
The ROOT interface has been removed as deprecated. The MCPWNLO code
has temporarily been removed from the Contrib directory as a major
review of this code is required. Additionally, there are various
fixes to all other codes shipped in Contrib.
** DIS improvements
The momentum reshuffling in DIS events has been improved.
** mu and nu beams
mu, nu_e and nu_mu and their antiparticles are now available as
beam particles. They are all supported in the DIS matrix
elements. mu+ mu- collisions are supported in the general
matrix element code for BSM models, but not yet in the hard-coded
matrix elements for lepton-lepton scattering.
** Structural changes
*** Inline code
Inline code has been merged into the header files, .icc files were
removed.
*** Silent build
By default, Herwig++ now builds with silent build rules. To get
the old behaviour, run 'make V=1'.
*** Debug level
The debug level on the command line will now always have priority.
*** Event counter
The event counter has been simplified.
*** Interpolator persistency
Interpolators can now be written persistently.
** Ticket #307: Momentum violation check in BasicConsistency
Added parameters AbsoluteMomentumTolerance and
RelativeMomentumTolerance
** Example POWHEG input files
The example input files for Powheg processes now set the NLO
alpha_S correctly, and are run as part of 'make check'.
** Truncated shower
A problem which lead to the truncated shower not being applied in
some cases has been fixed.
** Fixes to numerical problems
Minor problems with values close to zero were fixed in several
locations.
** Remove duplicated calculation of event shapes
An accidental duplication in the calculation of event shapes was
removed, they are now only calculated once per event. Several other
minor issues in the event shape calculations have also been fixed.
** MRST PDFs fixed
An initialization problem in the internal MRST PDFs was fixed.
** Vertex scale choice
The scale in the Vertex classes can now be zero where
possible.
** Treatment of -N flag
The Herwig++ main program now correctly treats the -N flag
as optional.
** Numerical stability improved
The numerical stability in the 'RunningMass' and
'QTildeReconstructor' classes has been improved. The
stability of the boosts in the SOPTHY code for the
simulation of QED radiation has been improved.
The accuracy of boosts in the z-direction has been improved to
fix problems with extremely high p_T partons.
** Bugfix in initial state splittings
A bug in the implementation of the PDF weight in initial-state
qbar -> qbar g splittings has been fixed.
** Bugfix in chargino neutralino vertices
A bug in the 'chi+- chi0 W-+' and charged
Higgs-sfermions vertices has been fixed.
** Remove uninitialized variables written to repository
A number of uninitialised variables which were written to the
repository have been initialised to zero to avoid problems on some
systems.
** Fix to QED radiation in hadronic collisions
The longitudinal boost of the centre-of-mass frame in hadronic
collisions is correctly accounted for now in the generation of QED
radiation.
** Fix to numerical problems in two-body decays
Numerical problems have been fixed, which appeared in the rare case
that the three-momenta of the decay products in two-body decays are
zero in the rest frame of the decay particle.
** A problem with forced splittings in the Remnant was fixed.
** ME correction for W+- decays applied properly
The matrix element correction for QCD radiation in W+- decays
which was not being applied is now correctly used.
** Top quark decays from SLHA file
The presence of top quark decay modes in SLHA files is now handled
correctly.
** Exceptional shower reconstruction kinematics
Additional protection against problems due to the shower
reconstruction leading to partons with x>1 has been added.
** Ordering of particles in BSM processes
Changes have been made to allow arbitrary ordering of the outgoing
particles in BSM processes.
** Bugfixes in tau decays
Two bugs involving tau decays have been fixed. The wrong masses
were used in the 'KPiCurrent' class for the scalar form factors
and a mistake in the selection of decay products lead to
tau- --> pi0 K- being generated instead of tau- --> eta K-.
** Avoid crashes in baryon number violating processes.
To avoid crashes, better protection has been introduced for the
case where diquarks cannot be formed from the quarks in a
baryon-number violating process. In addition, the parents of the
baryon-number violating clusters have been changed to avoid
problems with the conversion of the events to HepMC.
** QED radiation in W- decays
A bug in the 'QEDRadiationHandler' class which resulted
in no QED radiation being generated in W- decays has been fixed.
** A number of minor fixes to the SUSY models have been made.
** Partial width calculations in BSM models
A fix for the direction of the incoming particle in the calculation
of two-body partial widths in BSM models has been made.
** LoopTools improvements
The LoopTools cache is now cleared more frequently to
reduce the amount of memory used by the particle.
** Negative gluino masses are now correctly handled.
** A problem with mixing matrices which are not square has been fixed.
** Removed duplicate diagram
The 'MEee2gZ2ll' class has been fixed to only include the
photon exchange diagram once rather than twice as previously.
** Fix for duplicate particles in DecayConstructor
A problem has been fixed which occurred if the same particle was
included in the list of DecayConstructor:DecayParticles.
** Fixes for UED model vertices
A number of minor problems in the vertices for the UED model have
been fixed.
** Include missing symmetry factor
The missing identical-particle symmetry factor in
'MEPP2GammaGamma' has been included.
** Fix floating point problem in top decays
A floating point problem in the matrix element correction for top
decays has been fixed.
* Herwig++-2.4.2 release: 2009-12-11 (tagged at SVN r5022)
** Ticket #292: Tau decay numerical instability
The momentum assignment in tau decays contained numerical
instabilities which have been fixed by postponing the tau decay
until after the parton shower. A new interface setting
DecayHandler:Excluded is available to prevent decays in the shower
step. This is enabled by default for tau only.
** Ticket #290: Missing MSSM colour structure
The missing colour structure for gluino -> gluon neutralino was added.
** Ticket #294: Zero momentum in some decays
Some rare phase space points lead to zero momentum in two-body
decays. This has been fixed.
** Ticket #295: Stability of QED radiation for lepton collider processes
The numerical stability of QED radiation momenta was improved
further.
** Ticket #296: K0 oscillation vertex was wrong
The oscillation from K0 to K0_L/S now takes place at the production
vertex of K0.
** Ticket #289: Undefined variables in repository
On some system configurations, undefined variables were written to
the repository. These have been fixed.
** Fixed QED radiation for hadron processes
The longitudinal boost of the centre-of-mass frame in hadronic
collisions is correctly accounted for now.
** Numerical stability fixes
Small fixes in RunningMass and QTildeReconstructor.
** Powheg example input files
The example input files for Powheg processes now set the NLO
alpha_S correctly, and are run as part of 'make check'.
** OS X builds for Snow Leopard
Snow Leopard machines will now be recognized as a 64bit
architecture.
* Herwig++-2.4.1 release: 2009-11-19 (tagged at SVN r4932)
** Uses ThePEG-1.6.0
Herwig++ now requires ThePEG-1.6.0 to benefit from the improved
helicity code there. If you have self-written vertex classes, see
ThePEG's NEWS file for conversion instructions.
** Vertex improvements
ThePEG's new helicity code allowed major simplification of the vertex
implementations for all Standard Model and BSM physics models.
** New Transplanckian scattering model
An example configuration is in LHC-TRP.in
** BSM ModelGenerator as branching ratio calculator
The BSM ModelGenerator has a new switch to output the branching
ratios for a given SLHA file in SLHA format, which can then be used
elsewhere.
** BSM debugging: HardProcessConstructor
New interface 'Excluded' to exclude certain particles from
intermediate lines.
** Chargino-Neutralino-W vertex fixed
** Spin correlations
are now switched on by default for all perturbative decays.
** Ticket #276: Scale choice in BSM models' HardProcessConstructor
New interface 'ScaleChoice' to choose process scale between
- sHat (default for colour neutral intermediates) and
- transverse mass (default for all other processes).
** Ticket #287: Powheg process scale choice
The default choice is now the mass of the colour-singlet system.
** Ticket #278: QED radiation for BSM
Soft QED radiation is now enabled in BSM decays and all
perturbative decays by default.
** Ticket #279: Full 1-loop QED radiation for Z decays
Soft QED radiation in Z decays is now fully 1-loop by default.
** Ticket #280: Redirect all files to stdout
This is now implemented globally. The files previously ending in
-UE.out and -BSMinfo.out are now appended to the log file. They now
also obey the EventGenerator:UseStdout flag.
** Ticket #270: LaTeX output updated
After each run, a LaTeX file is produced that contains the full
list of citations. Please include the relevant ones in publications.
** Ticket #256: Mac OS X problems
An initialization problem that affected only some configurations has
been identified and fixed.
** Tests directory added
This contains many .in files, to exercise most matrix
elements.
** Minor fixes
*** Prevent rare x>1 partons in shower reconstruction.
*** SUSY-LHA parameter EXTPAR can be used to set tan beta
*** Improved Fastjet detection at configure time
* Herwig++-2.4.0 release: 2009-09-01 (tagged at SVN r4616)
** New matrix elements
We have added a built-in implementation of several new matrix elements:
PP --> WW / WZ / ZZ
PP --> W gamma / Z gamma
PP --> VBF Higgs
PP --> Higgs tt / Higgs bb
e+e- --> WW / ZZ
gamma gamma --> ff / WW
** Base code improvements
*** Ticket #257: Remnant handling
A problem with forced splittings in the Remnant was fixed.
*** Ticket #264: Soft matrix element correction
A problem with emissions form antiquarks was fixed.
** PDF sets
*** New default set
MRST LO** is the new default PDF set. LO* is also available built-in.
*** Shower PDFs can be set separately from the hard process
Use the 'ShowerHandler:PDF' interface.
** Parameter tunes
Shower, hadronization and underlying event parameters were retuned
against LEP and Tevatron data respectively.
** BSM module improvements
*** Ticket #259: read error for some UED models
Arbitrary ordering of outgoing lines in the process description is now
possible.
*** Ticket #266: branching ratio sums
The warning threshold for branching ratios not summing to 1 has
been relaxed. It is now a user interface parameter.
*** Ticket #267: Top decay modes
Top decay modes listed in SLHA files are now handled correctly.
** QED radiation
*** Ticket #241: Soft QED radiation is now enabled by default
*** Ticket #265: Radiation off W+ and W- is now handled correctly
** Interfaces
*** Ticket #243: Fastjet
Fastjet is now the only supported jet finder code. All example
analyses have been converted to use Fastjet.
*** KtJet and CLHEP interfaces have been removed.
*** New interfaces to AcerDet and PGS available in Contrib
*** MCPWnlo distributed in Contrib
*** HepMC and Rivet interfaces moved to ThePEG
** Ticket #239: Inelastic cross-section for MinBias
This information is now available in the ...-UE.out files.
** Technical changes
*** Ticket #186
Configure now looks for ThePEG in the --prefix location first.
*** Configure information
Important configuration information is listed at the end of the
'configure' run and in the file 'config.thepeg'. Please provide
this file in any bug reports.
*** New ZERO object
The ZERO object can be used to set any dimensionful quantity to
zero. This avoids explicit constructs like 0.0*GeV.
*** Exception specifiers removed
Client code changes are needed in doinit() etc., simply remove the
exception specifier after the function name.
*** Ticket #263: Tau polarizations can be forced in TauDecayer
* Herwig++-2.3.2 release: 2009-05-08 (tagged at SVN r4249)
** SUSY enhancements
*** Ticket #245: Select inclusive / exclusive production
Using the new 'HardProcessConstructor:Processes' switch options
'SingleParticleInclusive', 'TwoParticleInclusive' or 'Exclusive'
*** Improved three-body decay generation
Several problems were fixed, incl. tickets #249 #250 #251
Thanks to J.Tattersall and K.Rolbiecki for the stress-testing!
*** Looptools fix
Release 2.3.1 had broken the Looptools initialization.
*** Improved warning message texts
** Ticket #237:
Values of q2last can now be zero where possible.
** Ticket #240:
The Herwig++ main program now correctly treats the -N flag as optional.
** Ticket #246:
Extreme pT partons fixed by improving accuracy of z boosts.
** DIS
Improved parton shower momentum reshuffling.
** Minimum Bias events
The zero-momentum interacting particle used for
bookkeeping is now labelled as a pomeron.
** User Makefile
Makefile-UserModules does not enable -pedantic anymore. User's ROOT
code will not compile otherwise.
** Build system
Small fixes in the build system.
* Herwig++-2.3.1 release: 2009-03-31 (tagged at SVN r4140)
** Initial state showers
The PDF veto was wrongly applied to qbar->qbar g splittings.
** User interaction
The Makefile-UserModules now includes the Herwig version number.
The -N flag to 'Herwig++ run' is optional now, as was always intended.
** Contrib
The contrib directory is now included in the tarball. The omission
was accidental.
** Numerical accuracy
Minor problems with values close to zero were fixed in several
locations.
** LEP event shapes
An accidental duplication was removed, they are now only calculated
once per event.
** MRST PDF code
Initialization problem fixed.
** Mac OS X
The configure script was improved to detect libraries better.
** Libtool
Updated to version 2.2.6
* Herwig++-2.3.0 release: 2008-12-02 (tagged at SVN r3939)
** Major release, with many new features and bug fixes
** Extension to lepton-hadron collisions
** Inclusion of several processes accurate at next-to-leading order
in the POsitive Weight Hardest Emission Generator (POWHEG) scheme
** Inclusion of three-body decays and finite-width effects
in BSM processes
** New procedure for reconstructing kinematics of the parton shower
based on the colour structure of the hard scattering process
** New model for baryon decays including excited baryon multiplets
** Addition of a soft component to the multiple scattering model
of the underlying event and the option to choose more than one hard
scattering explicitly
** New matrix elements for DIS and e+e- processes
** New /Contrib directory added
containing external modules that will hopefully be of use to some
users but are not expected to be needed by most users and are not
supported at the same level as the main Herwig++ code
** Minor changes to improve the physics simulation:
*** IncomingPhotonEvolver added
to allow the simulation of partonic processes with incoming photons
in hadron collisions
*** KTRapidityCut added
to allow cuts on the p_T and rapidity, rather than just the p_T and
pseudorapidity used in SimpleKTCut. This is now used by default for
cuts on massive particles such as the $W^\pm$, $Z^0$ and Higgs
bosons and the top quark
*** Several changes to the decayers of B mesons
both to resolve problems with the modelling of partonic decays and
improve agreement with $\Upsilon(4s)$ data
*** Changes to allow values other than transverse mass of final-state particles as maximum transverse momentum for radiation in parton shower
either SCALUP for Les Houches events or the scale of the hard
process for internally generated hard processes
*** Changed defaults for intrinsic transverse momentum in hadron collisions
to 1.9GeV, 2.1GeV and 2.2GeV for the Tevatron and LHC at 10 TeV and
14 TeV, respectively
*** Pdfinfo object is now created in the HepMC interface
However in order to support all versions of HepMC containing this
feature the PDF set is not specified as not all versions contain
this information
*** New option of only decaying particles with lifetimes below user specified value
*** New options for the cut-off in the shower
and some obsolete parameters removed
*** Added option of switching off certain decay modes in BSM models
*** Added a Matcher for Higgs boson
to allow cuts to be placed on it
*** Diffractive particles deleted from default input files
they were not previously used
** Technical changes:
*** Some AnalysisHandler classes comparing to LEP data have been renamed
e.g. MultiplicityCount becomes LEPMultiplicityCount to avoid
confusion with those supplied in /Contrib for observables at the
Upsilon(4s) resonance
*** Reorganisation to remove the majority of the .icc files
by moving inlined functions to headers in an effort to improve
compile time
*** Restructured the decay libraries to reduce the amount of memory allocation
and de-allocation which improves run-time performance
*** The switch to turn off LoopTools has been removed
because LoopTools is now used by several core modules. As LoopTools
does not work on 64-bit platforms with g77 this build option is not
supported
*** Removed support for obsolete version of HepMC supplied with CLHEP
and improved the support for different units options with HepMC
*** EvtGen interface has been removed until it is more stable
*** Support for ROOT has been removed
it was not previously used
*** CKKW infrastructure has been removed from the release
until a concrete implementation is available
*** Default optimisation has been increased from -O2 to -O3
*** Handling of the fortran compiler has been improved
mainly due to improvements in the autotools
*** Use of FixedAllocator for Particle objects in ThePEG has been removed
as it had no performance benefits
** Bugs fixed:
*** Problems with the mother/daughter relations in the hard process
and diagram selection in W+- and Z0 production in association with a
hard jet
*** In general matrix element code for fermion-vector to fermion-scalar
where the outgoing fermion is coloured and the scalar neutral
*** In the selection of diagrams in some associated squark gaugino processes
*** h0->mu+mu- was being generated when h0->tau+tau-
*** Normalisation in the Histogram class for non unit-weight events
*** Protection against negative PDF values has been improved
these can occur when using NLO PDF sets
*** Lifetime for BSM particles is now automatically calculated
at the same time as the width
*** Hadrons containing a top quark now treated like hadrons containing BSM particles
in order to support this possibility
*** Several ambiguous uses of unsigned int
*** Several variables that may have been used undefined
*** Several memory leaks at initialisation
*** The configuration now aborts if no fortran compiler is found
as this is required to compile Looptools
*** Several minor floating point errors that did not affect results
* Herwig++-2.2.1 release: 2008-07-09 (tagged at SVN r3434)
** Ticket #181: BSM shower with a decay close to threshold
Now fixed.
** Ticket #191: Split SUSY crash
Improved error message.
** Ticket #192: using SCALUP as the pT veto in the shower
Now implemented.
** Ticket #194: production processes of ~chi_1(2)-
Fixed bug in the diagram creation.
** Removed unused particles
DiffractiveParticles.in was removed, they were never produced.
** Hadronization
Top quark clusters now possible, handled as 'exotic' clusters.
** Improved handling of decay modes
See ThePEG-1.3.0. 'defaultparticle' command is now obsolete.
** Multi-Parton interactions
Increased phase space sampling to have less than 1% uncertainty on
average multiplicity.
** New libtool version
gfortran is now used as default if it is available. Set FC=g77 to
override this.
** Fixed several memory leaks
** Memory allocation
Now using plain 'new' and 'delete'.
* Herwig++-2.2.0 release: 2008-04-18 (tagged at SVN r3195)
** Major release: now as stand-alone library
Herwig++ is now a stand-alone dlopen() plugin to ThePEG.
No compile-time linking to Herwig code is required. The Herwig++
binary is a simple executable steering ThePEG, which can
be replaced by other frontends (such as setupThePEG / runThePEG).
** New matrix elements
p p -> W + jet / Z + jet / W + higgs / Z + higgs
e+ e- -> Z + higgs
** Looptools
Updated to version 2.2.
** Ticket #141: segfault from using 'run' command
Fixed by using default allocators in Herwig++, and the
Repository::cleanup() method in ThePEG 1.2.0.
** Ticket #157: broken gsl library path on some 64bit systems
Paths with lib64 are correctly identified now.
** Ticket #159: p_t spectrum of ttbar pair
Fixed identical particle multiplier in Sudakov form factor.
** Ticket #161: glibc segfault
Rare segfault in MPI handler fixed.
** Ticket #165: rare infinite loop in four-body decay
All 4-body decays without dedicated decayers now use the Mambo algorithm.
A loop guard has been introduced to 3-body decays to avoid infinite retries.
** Ticket #166: rare infinite loop in top ME correction
These very rare events (O(1) in 10^7) close to mass threshold
now are discarded.
** Higgs width fixes
** SatPDF
Optionally, the PDF extrapolation behaviour outside a given range
can now be specified.
** gcc 4.3
Herwig++-2.2 compiles cleanly with the new gcc 4.3 series.
* Herwig++-2.1.4 release: 2008-03-03 (tagged at SVN r3024)
** Ticket #152: Vertex positions
All vertex positions of unphysical particles are set to zero until
a fix for the previous nonsensical values can be implemented.
* Herwig++-2.1.3 release: 2008-02-25 (tagged at SVN r2957)
** Ticket #129: Baryon decays
Fix for baryon decay modes.
** Ticket #131: HepMC
Check if IO_GenEvent exists
** Ticket #134: Hadronization
Smearing of hadron directions in cluster decay fixed.
** Ticket #137: HepMC
HepMC conversion allows specification of energy and length units to
be used.
** Ticket #139: Neutral kaons
Ratio K_L / K_S corrected.
** Ticket #140 / #141: Crash on shutdown
Event generation from the 'read' stage or an interface now shuts
down cleanly. Fixes a crash bug introduced in 2.1.1 which affected
external APIs to ThePEG / Herwig.
** Ticket #146: BSM models can be disabled
To save build time, some or all of the BSM models can be disabled
using the '--enable-models' configure switch.
** Reorganised .model files
The .model files now include the model-specific particles, too.
** Re-tune
Re-tuned hadronization parameters to LEP data.
** Other fixes in
QSPAC implementation in Shower; Multi-parton interaction tuning;
MRST initialization
* Herwig++-2.1.2 release: 2008-01-05 (tagged at SVN r2694)
** Ticket #127
Thanks to a patch submitted by Fred Stober, HepMCFile now can
output event files in all supported formats.
** Ticket #128
Fixed incorrect value of pi in histogram limits.
** Other fixes in
CKKW Qtilde clusterers, BSM width cut, SUSY mixing matrices.
* Herwig++-2.1.1 release: 2007-12-08 (tagged at SVN r2589)
** Bug #123
Fixed a bug with particle lifetimes which resulted in nan for some
vertex positions.
** Secondary scatters
Fixed bug which gave intrinsic pT to secondary scatters.
** gcc abs bug detection
configure now checks for and works around
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34130
** CKKW reweighting
Fixed wrong check for top quarks.
** MPIHandler
Fixed call order ambiguity.
* Herwig++-2.1.0 release: 2007-11-20 (tagged at SVN r2542)
** Major new release
Herwig++-2.1 includes significant improvements, including
multi-parton interactions, BSM physics and a new hadronic decay
model, tuned to LEP data.
For an overview of the changes, please see the release note
arXiv:0711.3137
* Herwig++-2.0.3 release: 2007-08-21 (tagged at SVN r2101)
** Bug #90
nan in top decay ME corrections fixed.
** unlisted
Colour flow fix in LightClusterDecayer
** unlisted
Updated version of MultiplicityCount analysis handler.
* Herwig++-2.0.2 release: 2007-07-06 (tagged at SVN r1716)
** Bug #80
Separation of HepMC from CLHEP is handled properly now.
** Bug #83
Workaround for OS X header problem
** unlisted
Veto on very hard emissions from Shower.
** unlisted
Detailed documentation in .in files
* Herwig++-2.0.1 release: 2006-12-05 (tagged at SVN r1195)
** Bug #54
ClusterFissioner vertex calculation fixed.
** Bug #57
Crash when showering W+jet events supplied by Les Houches interface.
** Bug #59
Fix for #57 applied to LHC events.
** Bug #60
Segfault when PDF is set to NoPDF.
** Bug #61
Missing weight factor for I=0 mesons
** Bug #62
Spinor vertex calculations broken when spinor rep is not default rep.
** Bug #63
Top decay never produces tau.
** Bug #69
TTbar and HiggsJet analysis handlers fixed.
** unlisted
Reorganization of Hadronization module gives 30% speedup.
Thanks to Vincenzo Innocente at CMS for his profiling work!
** unlisted
cleaner automake files in include/ and src/
** unlisted
Hw64 hadron selection algorithm 'abortnow' fixed.
** unlisted
Top/LeptonDalitzAnalysis removed (only worked with modified code).
** unlisted
removed f'_0 from particle list, decays were not handled
* Herwig++-2.0.0 release: 2006-09-28 (tagged at SVN r1066)
** Full simulation of hadron collisions

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