Helicity antenna showers for hadron colliders

Fischer, Nadine; Lifson, Andrew

doi:10.1140/epjc/s10052-017-5306-7

Cited by 20 publications

(30 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 This sample appears to be closer to SHERPA and also to the data, consistent with the studies in Ref. [86], which also suggest a good agreement with simulations that include higher-order effects. In general, the properties of gluon polarization inside unpolarized hadrons are largely unconstrained by experimental data (see e.g., Ref.…”

Section: Resultssupporting

confidence: 88%

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite

The fragmentation of high-energy gluons at small opening angles is largely unconstrained by present measurements. Gluon splitting to b-quark pairs is a unique probe into the properties of gluon fragmentation because identified b-tagged jets provide a proxy for the quark daughters of the initial gluon. In this study, key differential distributions related to the g → bb process are measured using 33 fb −1 of ffiffi ffi s p ¼ 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2016. Jets constructed from chargedparticle tracks, clustered with the anti-k t jet algorithm with radius parameter R ¼ 0.2, are used to probe angular scales below the R ¼ 0.4 jet radius. The observables are unfolded to particle level in order to facilitate direct comparisons with predictions from present and future simulations. Multiple significant differences are observed between the data and parton shower Monte Carlo predictions, providing input to improve these predictions of the main source of background events in analyses involving boosted Higgs bosons decaying into b-quarks.

show abstract

Section: Resultssupporting

confidence: 88%

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite

show abstract

“…We note that these functions exhibit the same singularity structures as corresponding "initial-final" (IF) antenna functions derived elsewhere [4,5], once general mass terms are allowed for in the latter. Somewhat arbitrarily we also choose the nonsingular terms to be the same for the IF and RF antenna functions, with minor changes relative to [4,5] to ensure that all of the IF and RF antenna functions remain positive over all of their respective phase spaces. This makes them straightforward to interpret in the probabilistic context of a Shower MC.…”

Section: Introductionmentioning

confidence: 52%

“…Massless initial-final and initial-initial antenna functions were presented in [38]. Finally helicity antennae were added in [5] for the massless case.…”

Section: B Massive Initial-final Antenna Functionsmentioning

confidence: 99%

“…For the sake of completeness, here we detail all massive initial-final antenna functions which have been changed relative to [5,38]. Aside from the addition of mass effects (obtained from crossing symmetry of massive final-final antennae [37]), some finite terms have been added in order to ensure all individual helicity antenna functions are positive-definite everywhere.…”

Section: Appendix A: Massive Helicity-dependent Initial-final Antennamentioning

confidence: 99%

See 1 more Smart Citation

Coherent showers in decays of colored resonances

Brooks

2019

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

We present a new approach to coherent parton showers in the decays of coloured resonances, based on the notion of "resonance-final" (RF) QCD antennae. A full set of mass-and helicity-dependent 2 → 3 antenna functions are defined, with the additional requirement of positivity over the respective branching phase spaces. Their singularity structure is identical to that of initial-final (IF) antennae in 2 → N hard processes (once mass terms associated with the incoming legs are allowed for), but the phase-space factorisations are different. The consequent radiation patterns respect QCD coherence (at leading colour) and reduce to DGLAP and eikonal kernels in the respective collinear and soft limits. The main novelty in the phase-space factorisation is that branchings in RF antennae impart a collective recoil to the other partons within the same decay system. An explicit implementation of these ideas, based on the Sudakov veto algorithm, is provided in the Vincia antenna-shower plug-in to the Pythia 8 Monte Carlo event generator. We apply our formalism, matched to next-to-leading order accuracy using Powheg , to top quark production at the LHC, and investigate implications for direct measurement of the top quark mass. Finally, we make recommendations for assessing theoretical uncertainties arising from parton showers in this context.

show abstract

“…In this paper, we set up an electroweak parton shower based on the spinor-helicity formalism. It is implemented in the Vincia parton shower [30][31][32] which is a plugin to the Pythia event generator and already allows for QCD evolution with partons of definite helicity states [33,34]. This feature is especially important in the electroweak theory due to its chiral nature.…”

Section: Introductionmentioning

confidence: 99%

Final-state QED multipole radiation in antenna parton showers

Kleiss

Verheyen

2017

J. High Energ. Phys.

View full text Add to dashboard Cite

We present a formalism for a fully coherent QED parton shower. The complete multipole structure of photonic radiation is incorporated in a single branching kernel. The regular on-shell 2 → 3 kinematic picture is kept intact by dividing the radiative phase space into sectors, allowing for a definition of the ordering variable that is similar to QCD antenna showers. A modified version of the Sudakov veto algorithm is discussed that increases performance at the cost of the introduction of weighted events. Due to the absence of a soft singularity, the formalism for photon splitting is very similar to the QCD analogon of gluon splitting. However, since no color structure is available to guide the selection of a spectator, a weighted selection procedure from all available spectators is introduced.

show abstract

Helicity antenna showers for hadron colliders

Cited by 20 publications

References 62 publications

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite

Coherent showers in decays of colored resonances

Final-state QED multipole radiation in antenna parton showers

Contact Info

Product

Resources

About

Helicity antenna showers for hadron colliders

Cited by 20 publications

References 62 publications

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at Aaboud1, Aad2, Abbott3 et al. 2019Phys. Rev. D10070View full textAdd to dashboardCite

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at Aaboud1, Aad2, Abbott3 et al. 2019Phys. Rev. D10070View full textAdd to dashboardCite

Coherent showers in decays of colored resonances

Final-state QED multipole radiation in antenna parton showers

Contact Info

Product

Resources

About

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite

Properties of g→bb¯ at small opening angles in pp collisions with the ATLAS detector at
Aaboud¹,
Aad²,
Abbott³
et al. 2019
Phys. Rev. D
10
0
7
0
View full text Add to dashboard Cite