Automated evaluation of electroweak Sudakov logarithms in SHERPA

Bothmann, Enrico; Napoletano, Davide

doi:10.1140/epjc/s10052-020-08596-2

Cited by 21 publications

(31 citation statements)

References 111 publications

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“…While such corrections are regulated by the EW scale, they are physically relevant without the inclusion of the associated real corrections, because those lead to different experimental signatures. Much work has already been done on the analytic calculation and resummation of these corrections [63][64][65][66][67][68][69][70][71]. Here, we illustrate that they may also be calculated with Vincia's EW shower.…”

Section: Electroweak Sudakov Logarithmsmentioning

confidence: 86%

Interleaved Resonance Decays and Electroweak Radiation in Vincia

Brooks¹,

Verheyen²

2021

Preprint

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We propose a framework for high-energy interactions in which resonance decays and electroweak branching processes are interleaved with the QCD evolution in a single common sequence of decreasing resolution scales. The interleaved treatment of resonance decays allows for a new treatment of finite-width effects in parton showers. At scales above their offshellness (i.e., typically Q > Γ), resonances participate explicitly as incoming and outgoing states in branching processes, while they are effectively "integrated out" of the description at lower scales. We implement this formalism, together with a full set of antenna functions for branching processes involving electroweak (W/Z/H) bosons in the Vincia shower module in Pythia 8.3, and study some of the consequences.

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Section: Electroweak Sudakov Logarithmsmentioning

confidence: 86%

Interleaved Resonance Decays and Electroweak Radiation in Vincia

Brooks¹,

Verheyen²

2021

Preprint

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“…The use of the numerical derivatives allows also to easily adapt the calculation of PR terms for possible BSM scenarios, where additional particles and couplings would be present. Moreover, at variance with what has been done in the recent automation [91] in the Sherpa framework, as all the other type of DL and SL logarithms the SL from PR terms are calculated exactly at O(α), without including spurious terms from higher orders in the α expansion. This fact is crucial for the systematic comparisons we are going to carry out in Secs 6 and 7 between NLO EW exact results and their Sudakov approximations.…”

Section: Derivative Of the Amplitudesmentioning

confidence: 98%

“…Refs. [79,91] and dubbed here as SDK 0 . The red lines are instead obtained by completely removing the QED contribution, namely, following the procedure described in Sec.…”

Section: Drell-yanmentioning

confidence: 99%

One-loop electroweak Sudakov logarithms: a revisitation and automation

Pagani,

Zaro

2021

Preprint

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In this work we revisit the algorithm of Denner and Pozzorini for the calculation of one-loop electroweak Sudakov logarithms and we automate it in the MadGraph5 aMC-@NLO framework. We adapt the formulas for modern calculations, keeping light-quarks and photons strictly massless and dealing with infrared divergencies via dimensional regularisation. We improve the approximation by taking into account additional logarithms that are angular dependent. We prove that an imaginary term has been previously omitted and we show that it cannot be in general neglected for 2 → n processes with n > 2. We extend the algorithm to NLO EW corrections to squared matrix-elements that involve also QCD corrections on top of subleading LO terms. Furthermore, we discuss the usage of this algorithm for approximating physical observables and cross sections. We propose a new approach in which the QED component is consistently removed and we show how it can be superior to the commonly used approaches. The relevance of all the novelties introduced in this work is corroborated by numerical results obtained for several processes in a complete automated way. We thoroughly compare exact NLO EW corrections and their Sudakov approximations both at the amplitude level and for physical observables in high-energy hadronic collisions.

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“…Electroweak virtual corrections can induce significant effects in the high transverse momentum region of V +jets final states and similar processes. These corrections originate in the emergence of electroweak Sudakov logarithms [28], which have recently been implemented in Sherpa [29]. They can also be modeled very efficiently in the EW virt approximation [30].…”

Section: Core Local K-factormentioning

confidence: 99%

Reducing negative weights in Monte Carlo event generation with Sherpa

Danziger¹,

Höche²,

Siegert³

2021

Preprint

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An increase in theoretical precision of Monte Carlo event generators is typically accompanied by an increased need for computational resources. One major obstacle are negative weighted events, which appear in Monte Carlo simulations with higher perturbative accuracy. While they can be handled somewhat easily in fixed-order calculations, they are a major concern for particle level event simulations. In this article, the origin of negative weights in the S-Mc@Nlo method is reviewed and mechanisms to reduce the negative weight fraction in simulations with the Sherpa event generator are presented, with a focus on V +jets and t t+jets simulations.

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Automated evaluation of electroweak Sudakov logarithms in SHERPA

Cited by 21 publications

References 111 publications

Interleaved Resonance Decays and Electroweak Radiation in Vincia

Interleaved Resonance Decays and Electroweak Radiation in Vincia

One-loop electroweak Sudakov logarithms: a revisitation and automation

Reducing negative weights in Monte Carlo event generation with Sherpa

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