A parton shower algorithm based on Catani-Seymour dipole factorisation

Abstract

In this publication the implementation of a new parton shower model based on the Catani-Seymour dipole factorisation, as first suggested by [1,2], is discussed. First results obtained with the new algorithm are compared with experimental data. 1 steffen@theory.phy.tu-dresden.de 2

Establishing jet scaling patterns with a photon

“…This way it does not only include the radiation of one or two hard jets, as correctly described by fixed-order QCD calculations, but any number of radiated jets including high multiplicities obviously well described by the parton shower. We use Sherpa [41][42][43] with its Ckkw [34,35] matching scheme to describe radiation of up to seven jets with high precision. Typically, we check an additional two more jets for unexpected features, but with correspondingly reduced statistics.…”

“…For our simulation we rely on Sherpa v1.3.0 [41][42][43] and its Ckkw matching up to five matrix element jets. We reconstruct jets using the anti-k T algorithm from FastJet [53][54][55] with R anti−k T = 0.4, which gives us a very moderate geometric separation of two jets.…”

Search for top squarks in final states with one isolated lepton, jets, and missing transverse momentum ins=13 TeVppAaboud1, Bergeås2, Brenner3 et al. 2016Phys. Rev. D540320View full textAdd to dashboardCite

“…(ii) POWHEG-BOX [52][53][54][55][56] interfaced to PYTHIA 6 [57] or HERWIG++ using the POWHEG method [58,59] for matching the NLO ME to the PS. (iii) SHERPA 2.1.1 [60] using Comix [61] and OpenLoops [62] ME generators interfaced with the SHERPA parton shower [63]. The CT10 [64] NLO parton distribution function (PDF) set is used for ME calculations with SHERPA and POWHEG-BOX and the NNPDF2.3 [65] PDF set is used for samples generated with MG5_AMC, except for the NLO samples, which use either CT10 or NNPDF3.0 [66].…”

Soft evolution of multi-jet final states

“…Monte Carlo parton showers [22][23][24], which describe the all-order evolution of QCD partons fully exclusively, have been extended beyond the strict collinear limit [25][26][27][28] and even beyond the 1/N C approximation [29,30]. They can be merged with LO predictions for multi-jet events [31][32][33][34] and matched to NLO calculations [35][36][37] for over a decade.…”