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Unitarising matrix element + parton shower merging

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Abstract

We revisit the CKKW-L method for merging tree-level matrix elements with parton showers, and amend it with an add/subtract scheme to minimise dependencies on the merging scale. The scheme is constructed to, as far as possible, recover the unitary nature of the underlying parton shower, so that the inclusive cross section is retained for each jet multiplicity separately.

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References

  1. N. Lavesson and L. Lönnblad, Extending CKKW-merging to One-Loop Matrix Elements, JHEP 12 (2008) 070 [arXiv:0811.2912] [INSPIRE].

    Article  ADS  Google Scholar 

  2. K. Hamilton and P. Nason, Improving NLO-parton shower matched simulations with higher order matrix elements, JHEP 06 (2010) 039 [arXiv:1004.1764] [INSPIRE].

    Article  ADS  Google Scholar 

  3. S. Hoche, F. Krauss, M. Schonherr and F. Siegert, NLO matrix elements and truncated showers, JHEP 08 (2011) 123 [arXiv:1009.1127] [INSPIRE].

    Article  ADS  Google Scholar 

  4. S. Alioli, K. Hamilton and E. Re, Practical improvements and merging of POWHEG simulations for vector boson production, JHEP 09 (2011) 104 [arXiv:1108.0909] [INSPIRE].

    Article  ADS  Google Scholar 

  5. K. Hamilton, P. Nason and G. Zanderighi, MINLO: Multi-Scale Improved NLO, JHEP 10 (2012) 155 [arXiv:1206.3572] [INSPIRE].

    Article  ADS  Google Scholar 

  6. T. Gehrmann, S. Hoche, F. Krauss, M. Schonherr and F. Siegert, NLO QCD matrix elements + parton showers in e + e − → hadrons, JHEP 01 (2013) 144 [arXiv:1207.5031] [INSPIRE].

    Article  ADS  Google Scholar 

  7. S. Hoeche, F. Krauss, M. Schonherr and F. Siegert, QCD matrix elements + parton showers: The NLO case, arXiv:1207.5030 [INSPIRE].

  8. R. Frederix and S. Frixione, Merging meets matching in MC@NLO, JHEP 12 (2012) 061 [arXiv:1209.6215] [INSPIRE].

    Article  ADS  Google Scholar 

  9. 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].

    Article  ADS  Google Scholar 

  10. 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].

    Article  ADS  Google Scholar 

  11. S. Alioli et al., Combining Higher-Order Resummation with Multiple NLO Calculations and Parton Showers in GENEVA, arXiv:1211.7049 [INSPIRE].

  12. S. Catani, F. Krauss, R. Kuhn and B. Webber, QCD matrix elements + parton showers, JHEP 11 (2001) 063 [hep-ph/0109231] [INSPIRE].

    Article  ADS  Google Scholar 

  13. L. Lönnblad, Correcting the color dipole cascade model with fixed order matrix elements, JHEP 05 (2002) 046 [hep-ph/0112284] [INSPIRE].

    Article  Google Scholar 

  14. N. Lavesson and L. Lönnblad, W+jets matrix elements and the dipole cascade, JHEP 07 (2005) 054 [hep-ph/0503293] [INSPIRE].

    Article  ADS  Google Scholar 

  15. S. Hoeche, F. Krauss, S. Schumann and F. Siegert, QCD matrix elements and truncated showers, JHEP 05 (2009) 053 [arXiv:0903.1219] [INSPIRE].

    Article  ADS  Google Scholar 

  16. L. Lönnblad and S. Prestel, Matching Tree-Level Matrix Elements with Interleaved Showers, JHEP 03 (2012) 019 [arXiv:1109.4829] [INSPIRE].

    Article  Google Scholar 

  17. M. Bengtsson and T. Sjöstrand, A Comparative Study of Coherent and Noncoherent Parton Shower Evolution, Nucl. Phys. B 289 (1987) 810 [INSPIRE].

    Article  ADS  Google Scholar 

  18. M. Bengtsson and T. Sjöstrand, Coherent Parton Showers Versus Matrix Elements: Implications of PETRA - PEP Data, Phys. Lett. B 185 (1987) 435 [INSPIRE].

    Article  ADS  Google Scholar 

  19. G. Miu, A Matrix element based modification of the parton shower, hep-ph/9804317 [INSPIRE].

  20. G. Miu and T. Sjöstrand, W production in an improved parton shower approach, Phys. Lett. B 449 (1999) 313 [hep-ph/9812455] [INSPIRE].

    Article  ADS  Google Scholar 

  21. 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].

    ADS  Google Scholar 

  22. W. Giele, D. Kosower and P. Skands, Higher-Order Corrections to Timelike Jets, Phys. Rev. D 84 (2011) 054003 [arXiv:1102.2126] [INSPIRE].

    ADS  Google Scholar 

  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].

    Article  ADS  MATH  Google Scholar 

  24. P. Nason, A New method for combining NLO QCD with shower Monte Carlo algorithms, JHEP 11 (2004) 040 [hep-ph/0409146] [INSPIRE].

    Article  ADS  Google Scholar 

  25. J. Alwall et al., A Standard format for Les Houches event files, Comput. Phys. Commun. 176 (2007) 300 [hep-ph/0609017] [INSPIRE].

    Article  ADS  Google Scholar 

  26. M. Cacciari, G.P. Salam and G. Soyez, FastJet User Manual, Eur. Phys. J. C 72 (2012) 1896 [arXiv:1111.6097] [INSPIRE].

    Article  ADS  Google Scholar 

  27. C. Balázs, J. Huston and I. Puljak, Higgs production: A Comparison of parton showers and resummation, Phys. Rev. D 63 (2001) 014021 [hep-ph/0002032] [INSPIRE].

    ADS  Google Scholar 

  28. R. Corke and T. Sjöstrand, Interleaved Parton Showers and Tuning Prospects, JHEP 03 (2011) 032 [arXiv:1011.1759] [INSPIRE].

    Article  ADS  Google Scholar 

  29. ATLAS collaboration, Summary of ATLAS PYTHIA 8 tunes, ATL-PHYS-PUB-2012-003 (2012).

  30. A. Buckley et al., Rivet user manual, arXiv:1003.0694 [INSPIRE].

  31. ATLAS collaboration, Study of jets produced in association with a W boson in pp collisions at \( \sqrt{s}=7 \) TeV with the ATLAS detector, Phys. Rev. D 85 (2012) 092002 [arXiv:1201.1276] [INSPIRE].

    ADS  Google Scholar 

  32. ATLAS collaboration, Study of Jet Shapes in Inclusive Jet Production in pp Collisions at \( \sqrt{s}=7 \) TeV using the ATLAS Detector, Phys. Rev. D 83 (2011) 052003 [arXiv:1101.0070] [INSPIRE].

    ADS  Google Scholar 

  33. ATLAS collaboration, Measurement of underlying event characteristics using charged particles in pp collisions at \( \sqrt{s}=900GeV \) and 7 TeV with the ATLAS detector, Phys. Rev. D 83 (2011) 112001 [arXiv:1012.0791] [INSPIRE].

    ADS  Google Scholar 

  34. M. Rubin, G.P. Salam and S. Sapeta, Giant QCD K-factors beyond NLO, JHEP 09 (2010) 084 [arXiv:1006.2144] [INSPIRE].

    Article  ADS  Google Scholar 

  35. F. Campanario and S. Sapeta, WZ production beyond NLO for high-pT observables, Phys. Lett. B 718 (2012) 100 [arXiv:1209.4595] [INSPIRE].

    Article  ADS  Google Scholar 

  36. S. Frixione and B.R. Webber, Matching NLO QCD computations and parton shower simulations, JHEP 06 (2002) 029 [hep-ph/0204244] [INSPIRE].

    Article  ADS  Google Scholar 

  37. S. Hoeche, F. Krauss, M. Schonherr and F. Siegert, A critical appraisal of NLO+PS matching methods, JHEP 09 (2012) 049 [arXiv:1111.1220] [INSPIRE].

    Article  ADS  Google Scholar 

  38. S. Hoeche, F. Krauss, M. Schonherr and F. Siegert, W+n-jet predictions with MC@NLO in Sherpa, Physical Review Letters (2012) [arXiv:1201.5882] [INSPIRE].

  39. V. Hirschi et al., Automation of one-loop QCD corrections, JHEP 05 (2011) 044 [arXiv:1103.0621] [INSPIRE].

    Article  ADS  Google Scholar 

  40. L. Lönnblad, Fooling Around with the Sudakov Veto Algorithm, arXiv:1211.7204 [INSPIRE].

  41. H.K. Dreiner, M. Krämer and J. Tattersall, How low can SUSY go? Matching, monojets and compressed spectra, Europhys. Lett. 99 (2012) 61001 [arXiv:1207.1613] [INSPIRE].

    Article  ADS  Google Scholar 

  42. L. Lönnblad and S. Prestel, Merging Multi-leg NLO Matrix Elements with Parton Showers, arXiv:1211.7278 [INSPIRE].

  43. S. Plätzer, Controlling inclusive cross sections in parton shower + matrix element merging, arXiv:1211.5467 [INSPIRE].

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Authors and Affiliations

  1. Dept. of Astronomy and Theoretical Physics, Lund University, Lund, Sweden

    Leif Lönnblad & Stefan Prestel

Authors
  1. Leif Lönnblad
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  2. Stefan Prestel
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Correspondence to Stefan Prestel.

Additional information

ArXiv ePrint: 1211.4827

Work supported in parts by the Swedish research council (contracts 621-2009-4076 and 621-2010-3326).

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Lönnblad, L., Prestel, S. Unitarising matrix element + parton shower merging. J. High Energ. Phys. 2013, 94 (2013). https://doi.org/10.1007/JHEP02(2013)094

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