Phenomenological MSSM interpretation of CMS searches in pp collisions at s = 7 $$ \sqrt{s}=7 $$ and 8 TeV

Abstract

Searches for new physics by the CMS collaboration are interpreted in the framework of the phenomenological minimal supersymmetric standard model (pMSSM). The data samples used in this study were collected at √ s = 7 and 8 TeV and have integrated luminosities of 5.0 fb −1 and 19.5 fb −1 , respectively. A global Bayesian analysis is performed, incorporating results from a broad range of CMS supersymmetry searches, as well as constraints from other experiments. Because the pMSSM incorporates several well-motivated assumptions that reduce the 120 parameters of the MSSM to just 19 parameters defined at the electroweak scale, it is possible to assess the results of the study in a relatively straightforward way. Approximately half of the model points in a potentially accessible subspace of the pMSSM are excluded, including all pMSSM model points with a gluino mass below 500 GeV, as well as models with a squark mass less than 300 GeV. Models with chargino and neutralino masses below 200 GeV are disfavored, but no mass range of model points can be ruled out based on the analyses considered. The nonexcluded regions in the pMSSM parameter space are characterized in terms of physical processes and key observables, and implications for future searches are discussed. Keywords: Hadron-Hadron scattering (experiments), SupersymmetryArXiv ePrint: 1606.03577Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP 3 .doi : The CMS collaboration 35 IntroductionSupersymmetry (SUSY) [1-6] is a strongly motivated candidate for physics beyond the standard model (SM). Searches for the superpartner particles (sparticles) predicted by SUSY performed in a variety of channels at the CERN LHC at √ s = 7 and 8 TeV have been reported [7][8][9][10][11][12][13][14][15][16][17][18]. The results, found to be consistent with the SM, are interpreted as limits on SUSY parameters, based mostly on models with restricted degrees of freedom, such as the constrained minimal supersymmetric standard model (cMSSM) [19][20][21][22][23][24][25], or, more recently, within the simplified model spectra (SMS) approach [26][27][28]. The cMSSM models feature specific relations among the soft-breaking terms at some mediation scale that translate into specific mass patterns typical for the model. While this problem is avoided in the SMS approach, the signatures of realistic models cannot always be fully covered by SMS topologies. This holds true, for instance, in the case of long decay chains that do not correspond to any SMS, t-channel exchanges of virtual sparticles in production, or the presence of multiple production modes that overlap in kinematic distributions. In the work reported here, data taken with the CMS experiment at the LHC are revisited with an alternative approach that is designed to assess more generally the coverage of SUSY parameter space provided by these searches. The method is based on the minimal supersymmetric standard model (MSSM) and combines several search channels and external constraints. Giv...

Phenomenological MSSM interpretation of CMS results

“…This installment of the proceedings highlights some key findings of [23], including how the 7 and 8 TeV CMS results constrain the MSSM, and sheds light on model points that evaded the CMS analyses, despite their having large SUSY production cross sections.…”

“…A subset of the findings in [23] has been presented. In the context of the phenomenological MSSM, sparticles with color charge have been ruled out below about 400 GeV, and the probability density of the LSP mass has been shifted to significantly higher values, as a result of a set of Run 1 CMS SUSY searches.…”

“…An analysis [23] of the viability of a potentially discoverable subset of the MSSM is presented in the context of a SUSY model who's range of allowed phenomena is more equivalent to that of the full MSSM compared with simplified models. The model, called the phenomenological MSSM (pMSSM) [22], is a submodel of the MSSM that makes a minimal number of assumptions about the MSSM, namely that…”

“…Most searches employ a counts likelihood based on the bin-by-bin observed and expected counts in all or most signal regions of the corresponding analysis, while others are based on χ 2 values derived from a global fit performed accross all bins of an analyses. Further details on the construction of the prior and likelihoods are given in [23].…”

NLO Higgs+jet production at large transverse momenta including top quark mass effects

“…Early Higgs studies during Run I, limited by statistics and energy, probed rather inclusive properties, and no significant deviations from the SM have been found [1][2][3][4][5][6][7]. Differential Higgs measurements [8][9][10][11][12][13][14] testing the SM were limited by statistics rather than theory predictions. Recent experimental analyses consider the Higgs boson in a highly boosted regime with transverse momenta (p T ) of 450 GeV to 1 TeV [15,16].…”