Automated simulations beyond the Standard Model: supersymmetry

Frixione, Stefano; Fuks, Benjamin; Hirschi, Valentin; Mawatari, Kentarou; Shao, Hua-Sheng; Sunder, Marthijn; Zaro, Marco

doi:10.1007/jhep12(2019)008

Cited by 36 publications

(60 citation statements)

References 373 publications

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“…A momentum reshuffling has to be imposed analogous to what has been advocated in Ref. [41] for an entirely different purpose. In the laboratory frame, the momentum of the first initial gluon is assigned as p g ¼ ð x 1 z E 1 ; 0; 0; x 1 z E 1 Þ, and all the external momenta of cg → J=ψc have been boosted to the same frame.…”

Section: Initial Charm Contribution and Variable Flavor Number Smentioning

confidence: 99%

J/ψ meson production in association with an open charm hadron at the LHC: A reappraisal

Shao

2020

Phys. Rev. D

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We critically (re)examine the associated production process of a J=ψ meson plus an open charm hadron at the LHC in the proton-proton (pp) and proton-lead (pPb) collisions. Such a process is very intriguing in the sense of tailoring to explore the double parton structure of nucleons and to determine the geometry of partons in nuclei. In order to interpret the existing pp data with the LHCb detector at the center-of-mass energy ffiffi ffi s p ¼ 7 TeV, we introduce two overlooked mechanisms for the double parton scattering (DPS) and single parton scattering (SPS) processes. Besides the conventional DPS mode, where the two mesons are produced almost independently in the two separate scattering subprocesses, we propose a novel DPS mechanism that the two constituent (heavy) quarks stemming from two hard scatterings can form into a composite particle, like the J=ψ meson, during the hadronization phase. It yields a strong correlation in the final state from the two distinct scattering subprocesses per hadron-hadron collision. Such a mechanism should be ubiquitous for quarkonium associated production processes involving more-than-one pair of same-flavor heavy quarks. However, it turns out the corresponding contribution is small in J=ψ þ cc hadroproduction. On the contrary, we point out that the resummation of the initial state logarithms due to gluon splitting into a charm quark pair is crucial to understand the LHCb measurement, which was overlooked in the literature. We perform a proper matching between the perturbative calculations in different initial-quark flavor number schemes, generically referring to the variable flavor number scheme. The new variable flavor number scheme calculation for the process strongly enhances the SPS cross sections, almost closing the discrepancies between theory and experiment. Finally, we present our predictions for the forthcoming LHCb measurement in pPb collisions at ffiffiffiffiffiffiffiffi s NN p ¼ 8.16 TeV. Some interesting observables are exploited to set up the control regions of the DPS signal and to probe the impactparameter-dependent parton densities in lead.

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Section: Initial Charm Contribution and Variable Flavor Number Smentioning

confidence: 99%

J/ψ meson production in association with an open charm hadron at the LHC: A reappraisal

Shao

2020

Phys. Rev. D

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“…It then compares the results with both data and the SM expectation, so that conclusive statements could be drawn. As in all recasting codes relying on the same method [2,4,5], the uncertainty on the signal is ignored although it could be relevant [7].…”

Section: Lhc Recasting With Madanalysismentioning

confidence: 99%

“…However, signal uncertainties are in general ignored by users in this procedure, although they could sometimes lead to incorrect interpretations [6]. With the limits on the masses of any hypothetical particle being pushed to higher and higher scales, the theoretical uncertainties related with the new physics signals can moreover sometimes be quite severe, in particular if the associated scale and Bjorken-x value lead to probing the parton densities in a regime in which they are poorly constrained [7].…”

Section: Introductionmentioning

confidence: 99%

Reinterpreting the results of the LHC with MadAnalysis 5: uncertainties and higher-luminosity estimates

2020

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The MadAnalysis 5 framework can be used to assess the potential of various LHC analyses for unraveling any specific new physics signal. We present an extension of the LHC reinterpretation capabilities of the programme allowing for the inclusion of theoretical and systematical uncertainties on the signal in the reinterpretation procedure. We have implemented extra methods dedicated to the extrapolation of the impact of a given analysis to higher luminosities, including various options for the treatment of the errors. As an application, we study three classes of new physics models. We first focus on a simplified model in which the Standard Model is supplemented by a gluino and a neutralino. We show that uncertainties could in particular degrade the bounds by several hundreds of GeV when considering 3000/fb of future LHC data. We next investigate another supersymmetry-inspired simplified model, in which the Standard Model is extended by a first generation squark species and a neutralino. We reach similar conclusions. Finally, we study a class of s-channel dark matter setups and compare the expectation for two types of scenarios differing in the details of the implementation of the mediation between the dark and Standard Model sectors.

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“…We then jointly use FeynRules with MoGRe (version 1.1) [69], NloCT (version 1.0.1) [70] and Fey-nArts (version 3.9) [71] to renormalize the bare Lagrangian introduced in the previous section with respect to O(α s ) QCD interactions. This in allows one to extract UV counterterms and so-called R 2 Feynman rules that are needed for numerical evaluation of one-loop integrals in four dimensions.…”

Section: Ii2 the Typeiiseesaw Ufo Librariesmentioning

confidence: 99%

Doubly charged Higgs boson production at hadron colliders

2020

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We present a systematic comparison of doubly charged Higgs boson production mechanisms at hadron colliders in the context of the Type II Seesaw model, emphasizing the importance of the higher-order corrections and subdominant channels. We consider the Drell-Yan channel at nextto-leading order in QCD, production via photon fusion at the leading order, gluon fusion with resummation of the threshold logarithms up to next-to-next-to-next-to-leading logarithmic accuracy, and same-sign weak boson fusion at next-to-leading order in QCD. For the Drell-Yan process, we study the impact of a static jet veto at next-to-leading-order matched to the resummation of jet veto scale logarithms at next-to-next-to-leading logarithmic accuracy. For the photon fusion channel, the dependence on modeling photon parton distribution functions is definitively assessed. To model vector boson fusion at next-to-leading order, we include all interfering topologies at O(α 4 ) and propose a method for introducing generator-level cuts within the MC@NLO formalism. Our results are obtained using a Monte Carlo tool chain linking the FeynRules, NloCT and Mad-Graph5 aMC@NLO programs and have necessitated the development of new, publicly available, Universal FeynRules Output libraries that encode the interactions between the Type II Seesaw scalars and the Standard Model particles. Libraries are compatible with both the normal and inverted ordering of the Majorana neutrino masses.

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Automated simulations beyond the Standard Model: supersymmetry

Cited by 36 publications

References 373 publications

J/ψ meson production in association with an open charm hadron at the LHC: A reappraisal

J/ψ meson production in association with an open charm hadron at the LHC: A reappraisal

Reinterpreting the results of the LHC with MadAnalysis 5: uncertainties and higher-luminosity estimates

Doubly charged Higgs boson production at hadron colliders

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