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Jet vetoing and Herwig++

  • Alex Schofield
  • Michael H. Seymour
Article

Abstract

We investigate the simulation of events with gaps between jets with a veto on additional radiation in the gap in Herwig++. We discover that the currently-used random treatment of radiation in the parton shower is generating some unphysical behaviour for wide-angle gluon emission in QCD 2 → 2 scatterings. We explore this behaviour quantitatively by making the same assumptions as the parton shower in the analytical calculation. We then modify the parton shower algorithm in order to correct the simulation of QCD radiation.

Keywords

Jets Hadronic Colliders QCD 

References

  1. [1]
    M. Dasgupta and G. Salam, Resummation of nonglobal QCD observables, Phys. Lett. B 512 (2001) 323 [hep-ph/0104277] [INSPIRE]. ADSGoogle Scholar
  2. [2]
    R. Appleby and M. Seymour, Nonglobal logarithms in interjet energy flow with k t clustering requirement, JHEP 12 (2002) 063 [hep-ph/0211426] [INSPIRE].ADSCrossRefGoogle Scholar
  3. [3]
    J.R. Forshaw, A. Kyrieleis and M. Seymour, Super-leading logarithms in non-global observables in QCD, JHEP 08 (2006) 059 [hep-ph/0604094] [INSPIRE].ADSCrossRefGoogle Scholar
  4. [4]
    J. Forshaw, A. Kyrieleis and M. Seymour, Super-leading logarithms in non-global observables in QCD: colour basis independent calculation, JHEP 09 (2008) 128 [arXiv:0808.1269] [INSPIRE].ADSCrossRefGoogle Scholar
  5. [5]
    J. Keates and M.H. Seymour, Super-leading logarithms in non-global observables in QCD: fixed order calculation, JHEP 04 (2009) 040 [arXiv:0902.0477] [INSPIRE].ADSCrossRefGoogle Scholar
  6. [6]
    A. Buckley, J. Butterworth, S. Gieseke, D. Grellscheid, S. Hoche, et al., General-purpose event generators for LHC physics, Phys. Rept. 504 (2011) 145 [arXiv:1101.2599] [INSPIRE].ADSCrossRefGoogle Scholar
  7. [7]
    S. Gieseke, D. Grellscheid, K. Hamilton, A. Papaefstathiou, S. Platzer, et al., HERWIG++ 2.5 release note, arXiv:1102.1672 [INSPIRE].
  8. [8]
    M. Bähr, S. Gieseke, M. Gigg, D. Grellscheid, K. Hamilton, et al., HERWIG++ physics and manual, Eur. Phys. J. C 58 (2008) 639 [arXiv:0803.0883] [INSPIRE].ADSCrossRefGoogle Scholar
  9. [9]
    ATLAS collaboration, Dijet production with a jet veto in pp collisions at \( \sqrt {s} = 7\,TeV \), ATLAS-CONF-2010-085 (2010).Google Scholar
  10. [10]
    J. Forshaw, J. Keates and S. Marzani, Jet vetoing at the LHC, JHEP 07 (2009) 023 [arXiv:0905.1350] [INSPIRE].ADSCrossRefGoogle Scholar
  11. [11]
    N. Kidonakis, G. Oderda and G.F. Sterman, Evolution of color exchange in QCD hard scattering, Nucl. Phys. B 531 (1998) 365 [hep-ph/9803241] [INSPIRE].ADSCrossRefGoogle Scholar
  12. [12]
    C.F. Berger, T. Kucs and G.F. Sterman, Energy flow in interjet radiation, Phys. Rev. D 65 (2002) 094031 [hep-ph/0110004] [INSPIRE].ADSGoogle Scholar
  13. [13]
    R. Appleby and M. Seymour, The resummation of interjet energy flow for gaps between jets processes at HERA, JHEP 09 (2003) 056 [hep-ph/0308086] [INSPIRE].ADSCrossRefGoogle Scholar
  14. [14]
    V. Sudakov, Vertex parts at very high-energies in quantum electrodynamics, Sov. Phys. JETP 3 (1956) 65 [INSPIRE].MathSciNetzbMATHGoogle Scholar
  15. [15]
    M.H. Seymour and M. Sjödahl, Symmetry of anomalous dimension matrices explained, JHEP 12 (2008) 066 [arXiv:0810.5756] [INSPIRE].ADSCrossRefGoogle Scholar
  16. [16]
    F. Maltoni, K. Paul, T. Stelzer and S. Willenbrock, Color flow decomposition of QCD amplitudes, Phys. Rev. D 67 (2003) 014026 [hep-ph/0209271] [INSPIRE].ADSGoogle Scholar
  17. [17]
    V. Gribov and L. Lipatov, Deep inelastic e p scattering in perturbation theory, Sov. J. Nucl. Phys. 15 (1972) 438 [INSPIRE].Google Scholar
  18. [18]
    G. Altarelli and G. Parisi, Asymptotic freedom in parton language, Nucl. Phys. B 126 (1977) 298 [INSPIRE].ADSCrossRefGoogle Scholar
  19. [19]
    Y.L. Dokshitzer, Calculation of the structure functions for deep inelastic scattering and e + e annihilation by perturbation theory in quantum chromodynamics., Sov. Phys. JETP 46 (1977)641 [INSPIRE].ADSGoogle Scholar
  20. [20]
    S. Gieseke, P. Stephens and B. Webber, New formalism for QCD parton showers, JHEP 12 (2003) 045 [hep-ph/0310083] [INSPIRE].ADSCrossRefGoogle Scholar
  21. [21]
    K. Odagiri, Color connection structure of supersymmetric QCD (22) processes, JHEP 10 (1998) 006 [hep-ph/9806531] [INSPIRE].ADSCrossRefGoogle Scholar
  22. [22]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].ADSCrossRefGoogle Scholar
  23. [23]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, A brief introduction to PYTHIA 8.1, Comput. Phys. Commun. 178 (2008) 852 [arXiv:0710.3820] [INSPIRE].ADSzbMATHCrossRefGoogle Scholar
  24. [24]
    T. Gleisberg, S. Hoeche, F. Krauss, M. Schonherr, S. Schumann, et al., Event generation with SHERPA 1.1, JHEP 02 (2009) 007 [arXiv:0811.4622] [INSPIRE].ADSCrossRefGoogle Scholar
  25. [25]
    S. Platzer and S. Gieseke, Dipole showers and automated NLO matching in HERWIG++, arXiv:1109.6256 [INSPIRE].
  26. [26]
    W.T. Giele, D.A. Kosower and P.Z. Skands, A simple shower and matching algorithm, Phys. Rev. D 78 (2008) 014026 [arXiv:0707.3652] [INSPIRE].ADSGoogle Scholar
  27. [27]
    A. Banfi, G. Corcella and M. Dasgupta, Angular ordering and parton showers for non-global QCD observables, JHEP 03 (2007) 050 [hep-ph/0612282] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    A. Martin, W. Stirling, R. Thorne and G. Watt, Parton distributions for the LHC, Eur. Phys. J. C 63 (2009) 189 [arXiv:0901.0002] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    G.P. Salam and G. Soyez, A practical seedless infrared-safe cone jet algorithm, JHEP 05 (2007) 086 [arXiv:0704.0292] [INSPIRE].ADSCrossRefGoogle Scholar
  30. [30]
    M. Cacciari and G.P. Salam, Dispelling the N 3 myth for the k t jet-finder, Phys. Lett. B 641 (2006) 57 [hep-ph/0512210] [INSPIRE].ADSGoogle Scholar
  31. [31]
    B.E. Cox, J.R. Forshaw and A.D. Pilkington, Extracting Higgs boson couplings using a jet veto, Phys. Lett. B 696 (2011) 87 [arXiv:1006.0986] [INSPIRE].ADSGoogle Scholar

Copyright information

© SISSA, Trieste, Italy 2012

Authors and Affiliations

  1. 1.School of Physics & AstronomyUniversity of ManchesterManchesterU. K.

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