Advertisement

An analytic initial-state parton shower

  • Wolfgang Kilian
  • Jürgen Reuter
  • Sebastian Schmidt
  • Daniel Wiesler
Open Access
Article

Abstract

We present a new algorithm for an analytic parton shower. While the algorithm for the final-state shower has been known in the literature, the construction of an initialstate shower along these lines is new. The aim is to have a parton shower algorithm for which the full analytic form of the probability distribution for all branchings is known. For these parton shower algorithms it is therefore possible to calculate the probability for a given event to be generated, providing the potential to reweight the event after the simulation. We develop the algorithm for this shower including scale choices and angular ordering. Merging to matrix elements is used to describe high-energy tails of distributions correctly. Finally, we compare our results with those of other parton showers and with experimental data from LEP, Tevatron and LHC.

Keywords

Jets Hadronic Colliders QCD NLO Computations 

References

  1. [1]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 Physics and Manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].ADSCrossRefGoogle Scholar
  2. [2]
    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].ADSMATHCrossRefGoogle Scholar
  3. [3]
    M. Bahr et al., HERWIG++ Physics and Manual, Eur. Phys. J. C 58 (2008) 639 [arXiv:0803.0883] [INSPIRE].ADSCrossRefGoogle Scholar
  4. [4]
    T. Gleisberg et al., Event generation with SHERPA 1.1, JHEP 02 (2009) 007 [arXiv:0811.4622] [INSPIRE].ADSCrossRefGoogle Scholar
  5. [5]
    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
  6. [6]
    C.W. Bauer and M.D. Schwartz, Event Generation from Effective Field Theory, Phys. Rev. D 76 (2007) 074004 [hep-ph/0607296] [INSPIRE].ADSGoogle Scholar
  7. [7]
    C.W. Bauer and F.J. Tackmann, Gaining analytic control of parton showers, Phys. Rev. D 76 (2007) 114017 [arXiv:0705.1719] [INSPIRE].ADSGoogle Scholar
  8. [8]
    C.W. Bauer, F.J. Tackmann and J. Thaler, GenEvA. II. A Phase space generator from a reweighted parton shower, JHEP 12 (2008) 011 [arXiv:0801.4028] [INSPIRE].ADSCrossRefGoogle Scholar
  9. [9]
    W. Kilian, T. Ohl and J. Reuter, WHIZARD: Simulating Multi-Particle Processes at LHC and ILC, Eur. Phys. J. C 71 (2011) 1742 [arXiv:0708.4233] [INSPIRE].ADSCrossRefGoogle Scholar
  10. [10]
    G. Gustafson and U. Pettersson, Dipole Formulation of QCD Cascades, Nucl. Phys. B 306 (1988) 746 [INSPIRE].ADSCrossRefGoogle Scholar
  11. [11]
    V. Sudakov, Vertex parts at very high-energies in quantum electrodynamics, Sov. Phys. JETP 3 (1956) 65 [INSPIRE].MathSciNetMATHGoogle Scholar
  12. [12]
    T. Sjöstrand, A Model for Initial State Parton Showers, Phys. Lett. B 157 (1985) 321 [INSPIRE].ADSGoogle Scholar
  13. [13]
    C.W. Bauer, F.J. Tackmann and J. Thaler, GenEvA. I. A New framework for event generation, JHEP 12 (2008) 010 [arXiv:0801.4026] [INSPIRE].ADSCrossRefGoogle Scholar
  14. [14]
    M. Moretti, T. Ohl and J. Reuter, OMega: An Optimizing matrix element generator, hep-ph/0102195 [INSPIRE].
  15. [15]
    T. Ohl, Vegas revisited: Adaptive Monte Carlo integration beyond factorization, Comput. Phys. Commun. 120 (1999) 13 [hep-ph/9806432] [INSPIRE].ADSMATHCrossRefGoogle Scholar
  16. [16]
    T. Ohl and J. Reuter, Testing the noncommutative standard model at a future photon collider, Phys. Rev. D 70 (2004) 076007 [hep-ph/0406098] [INSPIRE].ADSGoogle Scholar
  17. [17]
    M. Beyer et al., Determination of New Electroweak Parameters at the ILC - Sensitivity to New Physics, Eur. Phys. J. C 48 (2006) 353 [hep-ph/0604048] [INSPIRE].ADSCrossRefGoogle Scholar
  18. [18]
    J. Kalinowski, W. Kilian, J. Reuter, T. Robens and K. Rolbiecki, Pinning down the Invisible Sneutrino, JHEP 10 (2008) 090 [arXiv:0809.3997] [INSPIRE].ADSCrossRefGoogle Scholar
  19. [19]
    K. Hagiwara et al., Supersymmetry simulations with off-shell effects for CERN LHC and ILC, Phys. Rev. D 73 (2006) 055005 [hep-ph/0512260] [INSPIRE].ADSGoogle Scholar
  20. [20]
    W. Kilian, D. Rainwater and J. Reuter, Distinguishing little-Higgs product and simple group models at the LHC and ILC, Phys. Rev. D 74 (2006) 095003 [Erratum ibid. D 74 (2006) 099905] [hep-ph/0609119] [INSPIRE].ADSGoogle Scholar
  21. [21]
    A. Alboteanu, W. Kilian and J. Reuter, Resonances and Unitarity in Weak Boson Scattering at the LHC, JHEP 11 (2008) 010 [arXiv:0806.4145] [INSPIRE].ADSCrossRefGoogle Scholar
  22. [22]
    N.D. Christensen, C. Duhr, B. Fuks, J. Reuter and C. Speckner, Exploring the golden channel for HEIDI models using an interface between WHIZARD and FeynRules, arXiv:1010.3251 [INSPIRE].
  23. [23]
    J. Reuter and D. Wiesler, Distorted mass edges at LHC from supersymmetric leptoquarks, Phys. Rev. D 84 (2011) 015012 [arXiv:1010.4215] [INSPIRE].ADSGoogle Scholar
  24. [24]
    W. Kilian, J. Reuter and T. Robens, NLO Event Generation for Chargino Production at the ILC, Eur. Phys. J. C 48 (2006) 389 [hep-ph/0607127] [INSPIRE].ADSCrossRefGoogle Scholar
  25. [25]
    T. Robens, J. Kalinowski, K. Rolbiecki, W. Kilian and J. Reuter, (N)LO Simulation of Chargino Production and Decay, Acta Phys. Polon. B 39 (2008) 1705 [arXiv:0803.4161] [INSPIRE].ADSGoogle Scholar
  26. [26]
    T. Binoth et al., Next-to-leading order QCD corrections to ppb anti-bb anti-b + X at the LHC: the quark induced case, Phys. Lett. B 685 (2010) 293 [arXiv:0910.4379] [INSPIRE].ADSGoogle Scholar
  27. [27]
    N. Greiner, A. Guffanti, T. Reiter and J. Reuter, NLO QCD corrections to the production of two bottom-antibottom pairs at the LHC, Phys. Rev. Lett. 107 (2011) 102002 [arXiv:1105.3624] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    S. Catani, F. Krauss, R. Kuhn and B. Webber, QCD matrix elements + parton showers, JHEP 11 (2001) 063 [hep-ph/0109231] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    L. Lönnblad, Correcting the color dipole cascade model with fixed order matrix elements, JHEP 05 (2002) 046 [hep-ph/0112284] [INSPIRE].CrossRefGoogle Scholar
  30. [30]
    M. Mangano, Merging multijet MEs with shower MCs: some studies of systematics, talk given at ME/MC Tuning WG Meeting, Fermilab, Batavia, U.S.A., 15 November 2002.Google Scholar
  31. [31]
    M.L. Mangano, M. Moretti and R. Pittau, Multijet matrix elements and shower evolution in hadronic collisions: \( Wb\overline b \) + n jets as a case study, Nucl. Phys. B 632 (2002) 343 [hep-ph/0108069] [INSPIRE].ADSCrossRefGoogle Scholar
  32. [32]
    J. Alwall et al., Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions, Eur. Phys. J. C 53 (2008) 473 [arXiv:0706.2569] [INSPIRE].ADSCrossRefGoogle Scholar
  33. [33]
    S. Hoeche et al., Matching parton showers and matrix elements, hep-ph/0602031 [INSPIRE].
  34. [34]
    N. Lavesson and L. Lönnblad, Merging parton showers and matrix elements: Back to basics, JHEP 04 (2008) 085 [arXiv:0712.2966] [INSPIRE].ADSCrossRefGoogle Scholar
  35. [35]
    S. Catani, Y.L. Dokshitzer, M. Seymour and B. Webber, Longitudinally invariant K t clustering algorithms for hadron hadron collisions, Nucl. Phys. B 406 (1993) 187 [INSPIRE].ADSCrossRefGoogle Scholar
  36. [36]
    T. Sjöstrand and P.Z. Skands, Transverse-momentum-ordered showers and interleaved multiple interactions, Eur. Phys. J. C 39 (2005) 129 [hep-ph/0408302] [INSPIRE].ADSCrossRefGoogle Scholar
  37. [37]
    DELPHI collaboration, P. Abreu et al., Tuning and test of fragmentation models based on identified particles and precision event shape data, Z. Phys. C 73 (1996) 11 [INSPIRE].Google Scholar
  38. [38]
    DELPHI collaboration, P. Abreu et al., Measurement of event shape and inclusive distributions at \( \sqrt {s} = {13}0\;GeV \) and 136-GeV, Z. Phys. C 73 (1997) 229 [INSPIRE].Google Scholar
  39. [39]
    JADE collaboration, OPAL collaboration, P. Pfeifenschneider et al., QCD analyses and determinations of α s in e+e annihilation at energies between 35-GeV and 189-GeV, Eur. Phys. J. C 17 (2000) 19 [hep-ex/0001055] [INSPIRE].ADSCrossRefGoogle Scholar
  40. [40]
    S. Plätzer and S. Gieseke, Dipole Showers and Automated NLO Matching in HERWIG++, arXiv:1109.6256 [INSPIRE].
  41. [41]
    S. Plätzer, Parton Showers and Radiative Corrections in QCD, Ph.D. thesis, Karlsruhe Institute of Technology (2010).Google Scholar
  42. [42]
    G. Miu and T. Sjöstrand, W production in an improved parton shower approach, Phys. Lett. B 449 (1999) 313 [hep-ph/9812455] [INSPIRE].ADSGoogle Scholar
  43. [43]
    D0 collaboration, V.M. Abazov et al., Measurement of the normalized Z/γ * → μ + μ transverse momentum distribution in \( p\overline p \) collisions at \( \sqrt {s} = {1}.{96}\;TeV \), Phys. Lett. B 693 (2010) 522 [arXiv:1006.0618] [INSPIRE].ADSGoogle Scholar
  44. [44]
    CMS collaboration, S. Chatrchyan et al., Measurement of the Rapidity and Transverse Momentum Distributions of Z Bosons in pp Collisions at sqrt(s) = 7 TeV, Phys. Rev. D 85 (2012) 032002 [arXiv:1110.4973] [INSPIRE].ADSGoogle Scholar
  45. [45]
    W. Giele, D. Kosower and P. Skands, Higher-Order Corrections to Timelike Jets, Phys. Rev. D 84 (2011) 054003 [arXiv:1102.2126] [INSPIRE].ADSGoogle Scholar
  46. [46]
    G.P. Salam, A Practical seedless infrared safe cone algorithm, arXiv:0705.2696 [INSPIRE].

Copyright information

© SISSA, Trieste, Italy 2012

Authors and Affiliations

  • Wolfgang Kilian
    • 1
  • Jürgen Reuter
    • 2
  • Sebastian Schmidt
    • 2
  • Daniel Wiesler
    • 2
  1. 1.Department PhysikUniversität SiegenSiegenGermany
  2. 2.DESY Theory GroupHamburgGermany

Personalised recommendations