Tags give the ability to mark specific points in history as being important
  • v2.2.10
    Release v2.2.10

    Sherpa 2.2.10

    Version 2.2.10 contains bug fixes for several crashes, and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.10.tar.gz

    In can also be accessed via git in the web interface:

    • v2.2.10 as tag matching the release tarball
    • rel-2-2-10 as branch including potential further patches

    or cloned into a local working copy:

    • git clone -b rel-2-2-10 https://gitlab.com/sherpa-team/sherpa.git

    A Manual can be found online and in the Manual/ directory of the source. It is available in the HTML and INFO format and provides extensive documentation of all parameters.

    Changelog

    Enhancements

    • Further improvements for Rivet3 and HepMC3 compatibility !321 !314

    Runtime issues

    • Bugfix for crashes with new heavy-flavour shower evolution schemes !313
    • Bugfix for crash in ReweightWithoutSubevents !318
    • Bugfix for documentation signal blob with pre-NLO+PS kinematics !320
    • Bugfix for crash in setups with neutron beams !312

    Compilation issues

    • More robust discovery of HZTool and HepMC3 ROOT IO libraries !317 !322 !323

    Known issues

    • Dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
    • Also see our issue tracker

    References

    The main reference for Sherpa 2.2.x is arXiv:1905.09127. Please cite this publication if you have used Sherpa 2.2.x for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

  • v2.2.9
    Release v2.2.9

    Sherpa 2.2.9

    Version 2.2.9 contains bug fixes and a few new features, and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.9.tar.gz

    In can also be accessed via git in the web interface:

    • v2.2.9 as tag matching the release tarball
    • rel-2-2-9 as branch including potential further patches

    or cloned into a local working copy:

    • git clone -b rel-2-2-9 https://gitlab.com/sherpa-team/sherpa.git

    A Manual can be found online and in the Manual/ directory of the source. It is available in the HTML and INFO format and provides extensive documentation of all parameters.

    Changelog

    Enhancements

    • Multiplicative approximate EW corrections !262
    • New shower evolution/scale schemes for better b-fragmentation modelling !278
    • Add additional EW_SCHEME options for DY with sin2ThetaW input !274
    • Improve UFO structure for SMEFT () and allow to use form factors in UFO !290 !291
    • added option to limit couplings at amplitude level in comix

    Runtime issues

    • Respect polarisation of taus produced in hard decays (e.g. t -> b W (-> tau nu)) !296
    • Enable/Fix scale variations for loop generators that do not provide pole coefficients !259
    • Allow tau decays despite WIDTH[15]=0 !280

    Compilation issues

    • Remove usage of auto keyword to avoid C++11 requirement !279
    • Compile heavy-flavour-fusing hooks by default !228
    • Update Rivet_Interface to deal with Rivet3 and HepMC3 !254
    • Use -fcx-fortran-rules compiler flag by default !304

    Known issues

    • Dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
    • Also see our issue tracker

    References

    The main reference for Sherpa 2.2.x is arXiv:1905.09127. Please cite this publication if you have used Sherpa 2.2.x for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

  • v2.2.8
    Release v2.2.8

    Sherpa 2.2.8

    Version 2.2.8 is a bugfix release in the Cho Oyu series and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.8.tar.gz

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-8 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball (or the git-clone). It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference for Sherpa 2.2.x is arXiv:1905.09127. Please cite this publication if you have used Sherpa 2.2.x for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Enhancements

    • Phase space biasing with Enhance_Observable re-enabled for unweighted events (!193, !209)
    • Significant reduction of negative weight fraction possible with NLO_CSS_PSMODE=1 option for leading-colour S-event showering (!200)
    • Improve safeguarding against large Sudakov reweighting factors (!212)
    • HepMC 3.1 interface added (!196)
    • Rivet 3.x interface added (!192)
    • Make OpenLoops library finding more robust, e.g. for LCG OpenLoops installation (!215)

    Bugfixes (runtime issues)

    • Crash when soft spin correlations and neutral meson mixing were enabled (#53) -- thanks for the report from ATLAS
    • Widths updated in hard decay handler not used by ME generators (#182)

    Bugfixes (compilation issues)

    • None

    Known issues

    • Note that dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
    • Also see our issue tracker
  • v2.2.7   Release version 2.2.7
    Release v2.2.7

    Sherpa 2.2.7

    Version 2.2.7 is a bugfix release in the Cho Oyu series and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.7.tar.gz

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-7 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball (or the git-clone). It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference for Sherpa 2.2.x is arXiv:1905.09127. Please cite this publication if you have used Sherpa 2.2.x for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Known issues

    • Note that dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
    • Also see our issue tracker

    Enhancements

    • Add tools needed for the variable flavour number scheme in the multi-jet merging, cf. arXiv:1904.09382 (!146)
      • Add an option to cluster RS events in a fully ordered way (set COMIX_CLUSTER_RS_ORDERED=1)
      • Add a new scale scheme to the CS shower which should give better results for g->QQ splitting
      • Introduce a new scale tag P_TM2 defined as the root of the product of all transverse masses of all massive particles
    • Introduce new shower evolution schemes that take masses into account (set CSS_EVOLUTION_SCHEME=2 or 3) (!139)
    • Update default Lund string fragmentation parameters (!177)
    • Support the new analysis option feature in Rivet within the internal Rivet interface (!168)
    • Improve support for OpenLoops 2
    • Add an option to steer the total number of events generated in MPI event generation runs (!172)
    • Apply shower renormalisation scale factor to the strong coupling argument instead of re-defining AlphaS(mZ) (this improves the consistency of variations within Sherpa) (!145)
    • Add an option to switch on/off the multiple interaction library output (set MI_GENERATE_RESULTS_DIRECTORY=1 or 0) (!165)
    • Add an option to let the strong coupling value used in the shower freeze at a value of 1 instead of being cut off for low scales (this can mitigate cut-off issues when reweighting parton-shower emissions, cf. the manual) (!131)

    Bugfixes (runtime issues)

    • Fix wrong eikonals in the top-decay showering (#176)
    • Fix issues in the CS shower emission reweighting (!131)
      • Fix max coupling setting for renormalisation scale reweighting
      • Fix reweightings below the accepted emission scale
      • Ignore reweightings if the target strong coupling value is zero (due to a different cut-off, this improves the statistics of the reweighted event sample)
    • Adjust hadron masses correctly when providing custom masses via MASS (!156)
    • Fix an issue with the VAR scale setter if its value was based asymmetrically on parton momenta (!141)
    • Fix broken IGNOREBEAMS switch for the internal Rivet interface (!148)
    • Use status code 11 for incoming particles with a strong charge for the HepMC_Short output format (this improves comptability with Rivet)

    Bugfixes (compilation issues)

    • Replace C++ MPI bindings with C MPI bindings (C++ bindings were deprecated a long time ago and are not enabled per default in OpenMPI 4 (#77)
  • v2.2.6   Release version 2.2.6
    5cf79907 · implemented the above fix ·
    Release v2.2.6

    Sherpa 2.2.6

    Version 2.2.6 is a bugfix release in the Cho Oyu series and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.6.tar.gz

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-6 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball (or the git-clone). It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Known issues

    • Note that dijet production with additional jets merged with the CKKW algorithm is broken in the 2.2.x series (#46)
    • Also see our issue tracker

    Enhancements

    • Add initial-state p_z and inelasticity selectors for DIS (#80)
    • Improve the reweighting to include the local K=BBar/B factor in [email protected] runs (#73)
    • Improve treatment of the shower reweighting scale cut-off, it is now applied also when reweighting AlphaS and the PDFs in the CKKW clustering sequence (also mentioned in #73)
    • Adapt status=4 convention in the short HepMC output (#79)
    • Compute approximate NLO EW corrections (and subleading orders) as on-the-fly alternative event weights (#41). See Example in Manual for details. Currently only works with a soon-to-be-released version of OpenLoops.
    • Add a filter between the perturbative and the non-perturbative event phase, which can be used to reject events with parton-level cuts (!94)

    Bugfixes (runtime issues)

    • Fix NLO and Variable Selector routines (#70, #88)
    • Fix unweighting treatment for the LocalKFactor (and its on-the-fly variations) in negative events (#94)
    • Fix argument validation in GGH_KFactor_Setter::ClusterMassCorrectionFactor
    • Fix core scale setter for DIS when the incoming particles are ordered ep instead of pe and adapt it for ee->xy (where xy is not a quark pair) (!81)
    • Fix strong coupling reweighting in merging runs in cases where nothing was clustered (#66)
    • Fix beam remnants for DIS setups
    • Fix rejection of rare negative-energy configurations in the shower (#44)
    • Fix treatment of negative UserHook weights in HepMC interface (#100)
    • Fix a mapping in the OpenLoops parameter-setting interface (#87)
    • Fix HEFT Higgs production with COMIX (#114)
    • Fix compatibility issues with recent versions of Rivet

    Bugfixes (compilation issues)

    • Fix UFO model builder when running on Darwin (macOS)
    • Fix error when compiling with MCFM support
    • Fix compilation on ARM/PowerPC architectures
    • Make environment importing when building scons scripts more bullet-proof
    • Fix compilation of the HZTool interface add-on
  • v2.2.5   Release version 2.2.5
    786afa42 · bugfix in D_CC.C ·
    Release v2.2.5

    Sherpa 2.2.5

    Version 2.2.5 is a bugfix release in the Cho Oyu series and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here: SHERPA-MC-2.2.5.tar.gz

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-5 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball (or the git-clone). It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Known issues

    • As all releases in the v2.2.x series, dijet production using the multi-jet merging algorithm is broken, see #46. This is fixed in the upcoming v3.0. If you can not wait for it, you can use a v2.1.x release.

    Interface changes

    • Add preliminary support for HepMC3 (this interface is still being tested)

    New features

    • Improve decay showering off top quarks
    • Improve single-top support and add examples and documentation for its production channels
    • Improve hadronisation and hadron decays for heavy flavour production
    • Introduce a user hook framework which allows users to easily implement event generation afterburners, see Examples/Userhook
    • Add settings to output ME-only on-the-fly variations (along with the full ones):
      HEPMC_INCLUDE_ME_ONLY_VARIATIONS=1 (HepMC interface)
    • New cut-off for parton-shower reweighting:
      CSS_REWEIGHT_SCALE_CUTOFF=<pt_min>, default: 5 GeV^2
      this is more generally applicable than using a cut-off on the number of reweighted emissions
    • Improve support for on-the-fly variations of clustering steps (reweight each step locally instead of doing it globally)

    Bugfixes

    • Fix issue with the overweight treatment for negative weights
    • Add missing shower weight in some event outputs, e.g. when using OUTPUT HepMC...[]
    • Fix issue with the overweight threshold for on-the-fly variations
    • Fix issue with non-trivial beam spectra handling
    • Fix possible issues with electron-"PDF" initialization
    • Fix issue with the ISR-channel threshold for leptonic collider
    • Fix X/Y functions in METOOLS (this is relevant for hadron decays)
    • Fix crash in decay-channel sorting
    • Fix crash when using EVENT_TYPE=HadronDecay
    • Fix issue with CSS strong coupling values when using non-trivial scale factors
    • Fix issue with QSF variations for real emission calculations with COMIX
    • Fix crash when doing on-the-fly variations and invalid dipole kinematics occur
    • Fix issue in the interplay of the flux and the BIWeight for 1->n processes
    • Fix issue when using vertices with a vanishing coupling
    • Fix rare "invalid amplitude" crashes
    • Fix issues when adding limits for the number of t-channel propagators in matrix elements
    • Fix issue with checking PDF availability when enforcing jet vetoes
    • Fix several compilation issues
  • v2.2.4   Release version 2.2.4
    Release v2.2.4

    Sherpa 2.2.4

    Version 2.2.4 is a bugfix release in the Cho Oyu series and we encourage all users to update to this version.

    If you spot any problem, please send us an email. If you would like to be informed about newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    SHERPA-MC-2.2.4.tar.gz

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-4 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball (or the git-clone). It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Known issues

    • As all releases in the v2.2.x series, dijet production using the multi-jet merging algorithm is broken, see #46. This is fixed in the upcoming v3.0. If you can not wait for it, you can use a v2.1.x release.

    Interface changes

    • New default parameters for hadronisation model to improve heavy flavour production fractions and meson/baryon ratios (thanks to Andrii Verbytskyi).
    • Updates to Recola interface with some new parameter (names), please refer to the manual.
    • Make STRICT_METS the default scale setter to guarantee full scale setting accuracy for unweighted events.

    New features

    • Availability of DIRE NLO parton shower (cf. arXiv:1705.00742). This is not (yet) the default shower, in particular not in NLO-merged configurations.
    • Higher numerical stability in parton shower kinematics (re)construction.
    • Add OVERWEIGHT_THRESHOLD allowing user to cap maximal weight during event generation (cf. manual).
    • Avoid spuriously large weights in NLO-merged samples due to instable PDF ratios.
    • Add interface for hadron-level selectors.
    • Add Max_N_TChannels option in Amegic.
    • Add possibility to identify partons which originate in the hard decay handler.
    • Restructure gzip support such that it can be switched off at runtime (USE_GZIP).
    • Enable on-the-fly reweighting for calculations with the Higgs (Interference) add-on for HIGGS_INTERERENCE_MODE 1, 2, 3 or 4.

    Bugfixes

    • Bugfix in NLO-matched parton shower emission for non-trivial colour structures like in [email protected] This fixes an eta asymmetry which was visible at the ~2% level in such samples.
    • BSM models through UFO: fix running coupling behaviour and treatment of exotic color octets.
    • Bugfix in random generator for Poisson distributions with large mean values.
    • Bugfixes for segfaults and compiler warnings with gcc 7.1.
    • Bugfix for colour assignment in clustering for loop-induced merged processes.
    • Bugfix for decay showering in conjunction with NLO+PS matching.
  • v2.2.3   Version 2.2.3 is a bugfix release and adds the support of the Recola one-loop generator.
    Release v2.2.3

    Sherpa 2.2.3 (Cho Oyu)

    Version 2.2.3 is a bugfix release and adds the support of the Recola one-loop generator.

    If you spot any problem, please send us an email. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-3 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various

    different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    includes all bugfixes to Sherpa-2.2.2

    Interface changes

    • None

    New features

    • support of the Recola one-loop generator for QCD corrections
  • v2.2.2   Version 2.2.2 is a bugfix release.
    ac47ed9c · bump version number ·
    Release v2.2.2

    Sherpa 2.2.2 (Cho Oyu)

    Version 2.2.2 is a bugfix release.

    If you spot any problem, please send us an email. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-2 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various

    different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    includes all bugfixes to Sherpa-2.2.1

    Interface changes

    • None

    New features

    • None

    Last modified 3 years ago Last modified on Jan 25, 2017, 8:14:59 PM

  • v2.2.1   Version 2.2.1 is a feature-release based on the second NLO version of Sherpa. The program now allows to compute scale uncertainties for one and the same event sample on-the-fly in all types of simulation setups. There are no physics changes in this release, so events generated with the same run card should be identical to the ones in 2.2.0. A more detailed changelog can be found below.
    Release v2.2.1

    Sherpa 2.2.1 (Cho Oyu)

    Version 2.2.1 is a feature-release based on the second NLO version of Sherpa. The program now allows to compute scale uncertainties for one and the same event sample on-the-fly in all types of simulation setups. There are no physics changes in this release, so events generated with the same run card should be identical to the ones in 2.2.0. A more detailed changelog can be found below.

    If you spot any problem, please send us an email. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-1 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    includes all bugfixes to Sherpa-2.2.0

    Interface changes

    • TODO

    New features

  • v2.2.0   Version 2.2.0 is a feature-release based on the second NLO version of Sherpa. The program now supports the UFO model format, it allows to compute scale uncertainties for one and the same event sample on-the-fly, and it hosts a new parton shower.
    Release v2.2.0

    Sherpa 2.2.0 (Cho Oyu)

    Version 2.2.0 is a feature-release based on the second NLO version of Sherpa. The program now supports the UFO model format, it allows to compute scale uncertainties for one and the same event sample on-the-fly, and it hosts a new parton shower. A more detailed changelog can be found below.

    If you spot any problem, please send us an email. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-0 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Tests

    A test suite is now available for Sherpa. It can be obtained from svn

    Tests are prepared using 'scons sherpa=/path/to/sherpa', and run using './run.py'.

    Changelog

    Interface changes

    • New convention for Model names and coupling order specification. Most notably, the old Order_EW and Order_QCD switches have been replaced with a more generic Order switch, cf. our manual.
    • New default PDF: NNPDF3.0(NNLO) with NNPDFDriver version 1.0.5
    • New FSR/hadronisation tuning
    • New MPI/ISR tuning for default PDF
    • New and more convenient steering options for the enabling/disabling of hard decay channels, replacing the HDH_DECAY_ONLY and HDH_NO_DECAY options. Please refer to the manual for HDH_STATUS and HDH_WIDTH.

    New features

    • BSM models are supported via UFO, as described in EPJC75(2015)135.
    • The specification of coupling orders has changed to accomodate arbitrary BSM models, cf. Manual. This also allows to calculate interference terms directly. Most notably, the old Order_EW and Order_QCD switches have been replaced with a more generic Order switch, cf. our manual.
    • The full top-mass dependent gluon-Higgs interactions are implemented as described in JHEP02(2015)038.
    • The OpenLoops interface for one-loop contributions has been enhanced to support QCD-loop calculations with differing masses and Yukawa couplings, as far as they are supported by OpenLoops.
    • On the fly scale and PDF variations are supported for LO, LOPS, MEPS, NLO and NLOPS calculations, for details see Manual. Similarly, the weight components to perform arbitrary a posteriori scale variations can be written into HepMC's WeightContainer object, cf. Manual.
    • New switch HEPMC_TREE_LIKE that triggers straightening of GenEvent output to a more tree like structure by disconnecting particles coming in/out of parton shower vertex (id=4) to production/end vertices of type 1,2 or 3.
    • A new parton shower is implemented, as described in arXiv:1506.05057, but is not connected to the full matching/merging implementation and thus not used by default, yet.
    • Update of OpenLoops interface to remain compatible with future releases of OpenLoops.
    • Restore FixedDecays functionality.

    Bugfixes

    • A bug in the simulation of multiple parton scattering has been fixed. This will affect the rapidity spectra of low-pT jets.
    • A bug in the simulation of QED bremsstrahlung off W->lnu decays has been fixed. This affected the cut-off dependence of the radiative energy loss of the lepton.
    • A bug in the cluster hadronisation has been fixed. It lead to the very rare production of charge violating final states.
    • A bug has been fixed which was leading to infinite loops (stalling event generation) when tau spin correlations have been enabled simultaneously with multiple parton interactions.
    • Several bugs related to flavour remapping have been fixed in Amegic. These did previously lead to fatal error messages when using e.g. multi-vector-boson production processes in NLO+PS matching.
    • A significant difference between the integration results obtained with the METS and STRICT_METS scale setter in V+jets production has been fixed.
  • v2.1.1   Version 2.1.1 is a bugfix-release based on the second NLO version of Sherpa. A description of the issues which have been addressed can be found below. Additionally, the simulation of DIS at ep colliders has been re-validated.
    Release v2.1.1

    Sherpa 2.1.1 (Broad Peak)

    Version 2.1.1 is a bugfix-release based on the second NLO version of Sherpa. A description of the issues which have been addressed can be found below. Additionally, the simulation of DIS at ep colliders has been re-validated.

    If you spot any problem, please send us an email or post a ticket on trac. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-1-1 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker. If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    • A bug related to [email protected] has been fixed. This will affect the total cross section in heavy quark production at the level of few permille.
    • A bug related to parton showering in associated Higgs boson production has been fixed.
    • A problem related to SQLite database locking on IBM BG/Q systems has been solved. See these instructions
    • A bug related to CS subtraction with Comix has been fixed. This will eliminate possible large weights in events containing extremely soft gluons.
    • A bug related to the QED corrections on the hard interaction accidentally being switched off has been fixed.
    • A bug related to the contents of the HepMC::PdfInfo? object in [email protected] event generation has been fixed.
    • A bug in the underlying event simulation, presenting as a final state particle asymmetry, has been fixed. An update of the underlying event parameters was necessary, invalidating MPI grids generated with previous versions.
    • The Python interface to access Sherpa's matrix elements has been updated and supplemented with a C++ interface.
    • A bug in the CS subtraction in DRED has been fixed.

    New features

    • There are no new features compared to version 2.1.0
  • v2.1.0   Version 2.1.0 is the second NLO version of Sherpa. The main new feature compared to the 2.0.x series is the automated simulation of spin-correlated decay chains. Additionally, Comix may be used for simulating H events in [email protected], which speeds up initialization times and runtimes. This release improves upon the previous series by an extension of its physics capabilities and an extensive validation of all features already present in the 2.0.x series.
    Release v2.1.0

    Sherpa 2.1.0 (Broad Peak)

    Version 2.1.0 is the second NLO version of Sherpa. The main new feature compared to the 2.0.x series is the automated simulation of spin-correlated decay chains. Additionally, Comix may be used for simulating H events in [email protected], which speeds up initialization times and runtimes. This release improves upon the previous series by an extension of its physics capabilities and an extensive validation of all features already present in the 2.0.x series.

    If you spot any problem, please send us an email or post a ticket on trac. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-2-7 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker. If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    • We have introduced SQLite as the preferred storage manager. This may require some additional steps during installation, see this page. For installation on HPC systems, please refer to this page

    New features

    • Spin correlated decay chains (Comix only), includes all 1->2 and 1->3 decays allowed by the model, iterated to arbitrary decay chain length, all decay steps are dressed with QCD parton showers and QED corrections
    • [email protected] H events with Comix, speeds up initialisation and runtime
  • v2.0.0   Version 2.0.0 is the first NLO version of Sherpa. The main new feature compared to the 1.4.x series is the introduction of [email protected] merging. This release improves upon the previous beta series by an extension of its physics capabilities and an extensive validation of all features already present in the 1.4.x series.
    Release v2.0.0

    Sherpa 2.0.0 (Annapurna)

    Version 2.0.0 is the first NLO version of Sherpa. The main new feature compared to the 1.4.x series is the introduction of [email protected] merging. This release improves upon the previous beta series by an extension of its physics capabilities and an extensive validation of all features already present in the 1.4.x series.

    If you spot any problem, please send us an email or open an issue in gitlab. This will allow us to reach a mature version of the generator, suitable for all physics analyses. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-2-0-0 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker. If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    New features

  • v1.4.5   Version 1.4.5 is a bugfix release of Sherpa.
    53c1729c · revert accidental change ·
    Release v1.4.5

    Sherpa 1.4.5

    Version 1.4.5 is a bugfix release of Sherpa. Please see the Changelog below for a complete summary of the changes. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-4-5 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Note that this release is identical to 1.4.4 except for one changeset which was accidently missing in the original 1.4.4 tarball. The following changes are listed with respect to version 1.4.3:

    Bugfixes

    • Bugfix in amplitudes containing effective-theory couplings to the Higgs boson
    • Bugfix for issue in hadron decays: Some exotic particles were accidently produced and left stable without warning
    • Compile fixes for MacOS and gcc 4.7 compatibility
    • Improved multipole radiation pattern for ME QED corrections in the YFS approach

    Other changes with respect to 1.4.3

    • The default for the parameter UNITARIZATION_N in the model implementation of anomalous gauge couplings now has a default of '2' (instead of disabling unitarization by the previous default of '0')
  • v1.4.3   Version 1.4.3 is a convenience and bugfix release of Sherpa.
    a1c37cd2 · new METS mu_F patch ·
    Release v1.4.3

    Sherpa 1.4.3

    Version 1.4.3 is a convenience and bugfix release of Sherpa. Please see the Changelog below for a complete summary of the changes. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-4-3 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Changelog

    Bugfixes

    • Factorisation scale reliably stored in event record now

    New features

    • The minimal invariant mass allowed for any pair of particles in the hard scattering can now be adjusted with the parameter INT_MINSIJ_FACTOR=1.e-12, which will be multiplied with E_CMS^2 to implement the numerical cut-off.
    • Yukawa couplings in the Two-Higgs-Doublet-Model made more flexible
  • v1.4.2   Version 1.4.2 is a convenience and bugfix release of Sherpa. The main new feature compared to 1.4.1 is the introduction of the TUNE parameter which can be set to NNPDF23, NNPDF23_UEup, NNPDF23_UEdown, CT10, CT10_UEup, and CT10_UEdown. The CT10 option is the default setting (no change to 1.4.1), NNPDF23 provides settings for NNPDF 2.3, and the UEup and UEdown variants change the underlying event activity by +/-10%.
    Release v1.4.2

    Sherpa 1.4.2

    Version 1.4.2 is a convenience and bugfix release of Sherpa. The main new feature compared to 1.4.1 is the introduction of the TUNE parameter which can be set to NNPDF23, NNPDF23_UEup, NNPDF23_UEdown, CT10, CT10_UEup, and CT10_UEdown. The CT10 option is the default setting (no change to 1.4.1), NNPDF23 provides settings for NNPDF 2.3, and the UEup and UEdown variants change the underlying event activity by +/-10%.

    Please see the Changelog below for a complete summary of the changes. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-4-2 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker. If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    Bugfixes

    • Bugfix for CA flavour sorting, cf. #242
    • bugfix for NLO with universal selector

    New features

    • New TUNE parameter
  • v1.4.1   Version 1.4.1 is a bugfix release of Sherpa which does not contain any new features compared to 1.4.0.
    Release v1.4.1

    Sherpa 1.4.1

    Version 1.4.1 is a bugfix release of Sherpa which does not contain any new features compared to 1.4.0. Please see the Changelog below for a complete summary of the changes. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-4-1 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker (please log in with username "user" and password "sherpa"). If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    Bugfixes

    • Vertex offsets of hadron decays were missing in events with multiple "partonic" hadron decays. This becomes relevant when a detector simulation sensitive to vertex offsets is applied to the events and can impair the b-tagging performance.
    • Fixes for build failures for gcc 4.7, and in the Manual subdirectory, and with svn.make (cf. #228).
    • Bugfix for symmetry factor, cf. #172
    • Restriction of t-channels can be optionally limited to EW t-channels only. This is necessary for using this restriction in ME+PS merged samples. Nothing changes for the default (no t-channel restriction).
    • Consistency in the non-default EW_SCHEME's. Again, no changes for the default setup (EW_SCHEME=0).

    New features

    • None
  • v1.4.0   Version 1.4.0 is a major update of Sherpa which contains several new features.
    Release v1.4.0

    Sherpa 1.4.0

    Version 1.4.0 is a major update of Sherpa which contains several new features. Please see the Changelog below for a complete summary. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-4-0 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker (please log in with username "user" and password "sherpa"). If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    Changelog

    Bugfixes

    All patches available for previous versions are included in this release

    New features/Improvements

  • v1.3.1   Version 1.3.1 is a bugfix update of Sherpa which does not contain new features.
    c86e3755 · Change version number. ·
    Release v1.3.1

    Sherpa 1.3.1

    Version 1.3.1 is a bugfix update of Sherpa which does not contain new features. Please see the Changelog below for a complete summary. If you would like to be informed about patches and newer releases, please subscribe to our announcement mailing list.

    Download

    The Sherpa package can be downloaded here:

    In can also be accessed via git using

    • the web interface
    • or git clone -b rel-1-3-1 https://gitlab.com/sherpa-team/sherpa.git for a local clone.

    A Manual is included in the Manual/ directory of the tarball. It is available in the HTML and INFO format and provides extensive documentation of all parameters. It can also be found online.

    References

    The main reference describing the physics of Sherpa is JHEP02 (2009) 007. Please cite this publication if you have used Sherpa for your studies. Additionally, each run will produce a file called Sherpa_References.tex which contains information about the modules used in this run and the corresponding publications which should be referred. If in doubt, please seek the advice of the Sherpa Authors.

    Examples

    You can find a large collection of example setups for using SHERPA in various different colliders/processes in the Examples/ directory of the tarball. They are also described in the manual.

    Tunes for different PDFs

    In addition to the default PDF, we have also tuned Sherpa 1.3.1 with CTEQ6L1 and CT10. Here are the results:

    CTEQ6L1:

    K_PERP_MEAN_1 0.573
    K_PERP_MEAN_2 0.573
    K_PERP_SIGMA_1 0.898
    K_PERP_SIGMA_2 0.898
    PROFILE_PARAMETERS 0.884 0.828
    RESCALE_EXPONENT 0.244
    SCALE_MIN 2.65
    SIGMA_ND_FACTOR 0.788

    CT10:

    K_PERP_MEAN_1 1.17
    K_PERP_MEAN_2 1.17
    K_PERP_SIGMA_1 0.760
    K_PERP_SIGMA_2 0.760
    PROFILE_PARAMETERS 0.576 0.353
    RESCALE_EXPONENT 0.238
    SCALE_MIN 2.52
    SIGMA_ND_FACTOR 0.465

    Patches/known problems/known bugs/FAQs

    All known problems/questions and their solutions can be found on our issue tracker (please log in using the given details). If you encounter any problem while installing or running Sherpa, please open a new issue in the tracker.

    • Suppressing unitarisation output in SM+AGC model, not currently listed on the bug tracker. Fix: Apply patch file via patch -p0 < AGC-output.patch in the top level directory of your Sherpa installation, and recompile using 'make install'.

    Changelog

    Bugfixes w.r.t. Version 1.3.0

    All patches available for previous versions are included in this release:

    • Bugfix for MPI shower setup and corresponding new tune
    • Bugfix for MPI initialization and QCD simulations
      cf. ticket 180
    • Bugfixes for ME level NLO event generation

    New features/Improvements

    • None