Abstract
In this article we generalise Powheg next-to-leading order parton shower (Nlops) simulations of vector boson production and vector boson production in association with a single jet, to give matrix element corrected Menlops simulations. In so doing we extend and provide, for the first time, an exact and faithful implementation of the Menlops formalism in hadronic collisions. We also consider merging the resulting event samples according to a phase space partition defined in terms of an effective jet clustering scale. The merging scale is restricted such that the component generated by the associated production simulation does not impact on the NLO accuracy of inclusive vector boson production observables. The dependence of the predictions on the unphysical merging scale is demonstrated. Comparisons with Tevatron and LHC data are presented.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
S. Catani, F. Krauss, R. Kuhn and B.R. Webber, QCD matrix elements + parton showers, JHEP 11 (2001) 063 [hep-ph/0109231] [SPIRES].
M.L. Mangano, M. Moretti and R. Pittau, Multijet matrix elements and shower evolution in hadronic collisions: \( Wb\bar{b} + n \) jets as a case study, Nucl. Phys. B 632 (2002) 343 [hep-ph/0108069] [SPIRES].
L. Lönnblad, Correcting the colour-dipole cascade model with fixed order matrix elements, JHEP 05 (2002) 046 [hep-ph/0112284] [SPIRES].
F. Krauss, Matrix elements and parton showers in hadronic interactions, JHEP 08 (2002) 015 [hep-ph/0205283] [SPIRES].
S. Mrenna and P. Richardson, Matching matrix elements and parton showers with HERWIG and PYTHIA, JHEP 05 (2004) 040 [hep-ph/0312274] [SPIRES].
S. Frixione and B.R. Webber, Matching NLO QCD computations and parton shower simulations, JHEP 06 (2002) 029 [hep-ph/0204244] [SPIRES].
P. Nason, A new method for combining NLO QCD with shower Monte Carlo algorithms, JHEP 11 (2004) 040 [hep-ph/0409146] [SPIRES].
S. Frixione, P. Nason and C. Oleari, Matching NLO QCD computations with parton shower simulations: the Powheg method, JHEP 11 (2007) 070 [arXiv:0709.2092] [SPIRES].
S. Alioli, P. Nason, C. Oleari and E. Re, A general framework for implementing NLO calculations in shower Monte Carlo programs: the Powheg BOX, JHEP 06 (2010) 043 [arXiv:1002.2581] [SPIRES].
S. Hoche, F. Krauss, M. Schonherr and F. Siegert, Automating the Powheg method in Sherpa, JHEP 04 (2011) 024 [arXiv:1008.5399] [SPIRES].
R. Frederix et al., Scalar and pseudoscalar Higgs production in association with a top-antitop pair, Phys. Lett. B 701 (2011) 427 [arXiv:1104.5613] [SPIRES].
R. Frederix et al., W and Z/γ * boson production in association with a bottom-antibottom pair, JHEP 09 (2011) 061 [arXiv:1106.6019] [SPIRES].
S. Alioli, K. Hamilton, P. Nason, C. Oleari and E. Re, Jet pair production in Powheg, JHEP 04 (2011) 081 [arXiv:1012.3380] [SPIRES].
S. Alioli, P. Nason, C. Oleari and E. Re, Vector boson plus one jet production in Powheg, JHEP 01 (2011) 095 [arXiv:1009.5594] [SPIRES].
A. Kardos, C. Papadopoulos and Z. Trócsányi, Top quark pair production in association with a jet with NLO parton showering, arXiv:1101.2672 [SPIRES].
T. Melia, P. Nason, R. Rontsch and G. Zanderighi, W + W + plus dijet production in the Powheg BOX, Eur. Phys. J. C 71 (2011) 1670 [arXiv:1102.4846] [SPIRES].
C. Oleari and L. Reina, \( Wb\bar{b} \) production in Powheg, arXiv:1105.4488 [SPIRES].
Z. Nagy and D.E. Soper, Matching parton showers to NLO computations, JHEP 10 (2005) 024 [hep-ph/0503053] [SPIRES].
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] [SPIRES].
N. Lavesson and L. Lönnblad, Extending CKKW-merging to one-loop matrix elements, JHEP 12 (2008) 070 [arXiv:0811.2912] [SPIRES].
C.W. Bauer, F.J. Tackmann and J. Thaler, GenEvA. I. A new framework for event generation, JHEP 12 (2008) 010 [arXiv:0801.4026] [SPIRES].
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] [SPIRES].
W.T. Giele, D.A. Kosower and P.Z. Skands, Higher-order corrections to timelike jets, arXiv:1102.2126 [SPIRES].
K. Hamilton and P. Nason, Improving NLO-parton shower matched simulations with higher order matrix elements, JHEP 06 (2010) 039 [arXiv:1004.1764] [SPIRES].
S. Hoche, F. Krauss, M. Schonherr and F. Siegert, NLO matrix elements and truncated showers, JHEP 08 (2011) 123 [arXiv:1009.1127] [SPIRES].
P. Nason and G. Ridolfi, A positive-weight next-to-leading-order Monte Carlo for Z pair hadroproduction, JHEP 08 (2006) 077 [hep-ph/0606275] [SPIRES].
J. Pumplin et al., New generation of parton distributions with uncertainties from global QCD analysis, JHEP 07 (2002) 012 [hep-ph/0201195] [SPIRES].
M.R. Whalley, D. Bourilkov and R.C. Group, The Les Houches Accord PDFs (LHAPDF) and Lhaglue, hep-ph/0508110 [SPIRES].
A. Buckley et al., Rivet user manual, arXiv:1003.0694 [SPIRES].
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] [SPIRES].
R. Corke and T. Sjöstrand, Improved parton showers at large transverse momenta, Eur. Phys. J. C 69 (2010) 1 [arXiv:1003.2384] [SPIRES].
R. Corke and T. Sjöstrand, Interleaved parton showers and tuning prospects, JHEP 03 (2011) 032 [arXiv:1011.1759] [SPIRES].
R. Corke and T. Sjöstrand, Multiparton interactions with an x-dependent proton size, JHEP 05 (2011) 009 [arXiv:1101.5953] [SPIRES].
M.H. Seymour, A simple prescription for first order corrections to quark scattering and annihilation processes, Nucl. Phys. B 436 (1995) 443 [hep-ph/9410244] [SPIRES].
M.H. Seymour, Matrix element corrections to parton shower algorithms, Comp. Phys. Commun. 90 (1995) 95 [hep-ph/9410414] [SPIRES].
G. Miu and T. Sjöstrand, W production in an improved parton shower approach, Phys. Lett. B 449 (1999) 313 [hep-ph/9812455] [SPIRES].
G. Corcella and M.H. Seymour, Initial state radiation in simulations of vector boson production at hadron colliders, Nucl. Phys. B 565 (2000) 227 [hep-ph/9908388] [SPIRES].
G. Bozzi, S. Catani, G. Ferrera, D. de Florian and M. Grazzini, Production of Drell-Yan lepton pairs in hadron collisions: transverse-momentum resummation at next-to-next-to-leading logarithmic accuracy, Phys. Lett. B 696 (2011) 207 [arXiv:1007.2351] [SPIRES].
M. Rubin, G.P. Salam and S. Sapeta, Giant QCD K-factors beyond NLO, JHEP 09 (2010) 084 [arXiv:1006.2144] [SPIRES].
K. Hamilton, P. Richardson and J. Tully, A positive-weight next-to-leading order Monte Carlo simulation of Drell-Yan vector boson production, JHEP 10 (2008) 015 [arXiv:0806.0290] [SPIRES].
K. Hamilton, P. Richardson and J. Tully, A positive-weight next-to-leading order Monte Carlo simulation for Higgs boson production, JHEP 04 (2009) 116 [arXiv:0903.4345] [SPIRES].
K. Hamilton, A positive-weight next-to-leading order simulation of weak boson pair production, JHEP 01 (2011) 009 [arXiv:1009.5391] [SPIRES].
K. Hamilton, P. Richardson and J. Tully, A modified CKKW matrix element merging approach to angular-ordered parton showers, JHEP 11 (2009) 038 [arXiv:0905.3072] [SPIRES].
R.K. Ellis and S. Veseli, W and Z transverse momentum distributions: resummation in q T space, Nucl. Phys. B 511 (1998) 649 [hep-ph/9706526] [SPIRES].
Y.L. Dokshitzer, D. Diakonov and S.I. Troian, Hard processes in quantum chromodynamics, Phys. Rept. 58 (1980) 269 [SPIRES].
P. Nason, MINT: a computer program for adaptive Monte Carlo integration and generation of unweighted distributions, arXiv:0709.2085 [SPIRES].
M. Dobbs and J.B. Hansen, The HepMC C++ Monte Carlo event record for high energy physics, Comput. Phys. Commun. 134 (2001) 41 [SPIRES].
CDF collaboration, T.A. Aaltonen et al., Measurement of dσ/dy of Drell-Yan e + e − pairs in the Z mass region from \( p\bar{p} \) collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Lett. B 692 (2010) 232 [arXiv:0908.3914] [SPIRES].
DØ collaboration, V.M. Abazov et al., Precise study of the Z/γ * boson transverse momentum distribution in ppbar collisions using a novel technique, Phys. Rev. Lett. 106 (2011) 122001 [arXiv:1010.0262] [SPIRES].
DØ collaboration, B. Abbott et al., Differential cross-section for W boson production as a function of transverse momentum in \( p\bar{p} \) collisions at \( \sqrt {s} = 1.8 \) TeV, Phys. Lett. B 513 (2001) 292 [hep-ex/0010026] [SPIRES].
DØ collaboration, V.M. Abazov et al., Measurement of the normalized Z/γ* → μ + μ − transverse momentum distribution in \( p\bar{p} \) collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Lett. B 693 (2010) 522 [arXiv:1006.0618] [SPIRES].
CDF — Run II collaboration, T. Aaltonen et al., Measurement of inclusive jet cross-sections in Z/γ*(→ e + e −) + jets production in \( p\bar{p} \) collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Rev. Lett. 100 (2008) 102001 [arXiv:0711.3717] [SPIRES].
DØ collaboration, V.M. Abazov et al., Measurement of Z/γ * + jet + X angular distributions in \( p\bar{p} \) collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Lett. B 682 (2010) 370 [arXiv:0907.4286] [SPIRES].
ATLAS collaboration, G. Aad et al., Measurement of the production cross section for W-bosons in association with jets in pp collisions at sqrts = 7 TeV with the ATLAS detector, Phys. Lett. B 698 (2011) 325 [arXiv:1012.5382] [SPIRES].
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1108.0909
Rights and permissions
Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
About this article
Cite this article
Alioli, S., Hamilton, K. & Re, E. Practical improvements and merging of Powheg simulations for vector boson production. J. High Energ. Phys. 2011, 104 (2011). https://doi.org/10.1007/JHEP09(2011)104
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP09(2011)104