Shoaib Munir

Constrained MSSM favoring new territories: The impact of new LHC limits and a 125 GeV Higgs boson

We present an updated and extended global analysis of the Constrained MSSM (CMSSM) taking into account new limits on supersymmetry from ~5/fb data sets at the LHC. In particular, in the case of the razor limit obtained by the CMS Collaboration we simulate detector efficiency for the experimental analysis and derive an approximate but accurate likelihood function. We discuss the impact on the global fit of a possible Higgs boson with mass near 125 GeV, as implied by recent data, and of a new improved limit on BR(B_s->\mu\mu). We identify high posterior probability regions of the CMSSM parameters as the stau-coannihilation and the A-funnel region, with the importance of the latter now being much larger due to the combined effect of the above three LHC results and of dark matter relic density. We also find that the focus point region is now disfavored. Ensuing implications for superpartner masses favor even larger values than before, and even lower ranges for dark matter spin-independent cross section, \sigma^{SI}_p s\gamma) and BR(B_s->\mu\mu).

Constrained next-to-minimal supersymmetric standard model with a 126 GeV Higgs boson: A global analysis

We present the first global analysis of the Constrained NMSSM that investigates the impact of the recent discovery of a 126 GeV Higgs-like boson, of the observation of a signal for branching ratio BR (Bs → μ+μ−), and of constraints on supersymmetry from ∼ 5/fb of data accumulated at the LHC, as well as of other relevant constraints from colliders, flavor physics and dark matter. We consider three possible cases, assuming in turn that the discovered Higgs boson is (i) the lightest Higgs boson of the model; (ii) the next-to-lightest Higgs boson; and (iii) a combination of both roughly degenerate in mass. The likelihood function for the Higgs signal uses signal rates in the γγ and ZZ → 4l channels, while that for the Higgs exclusion limits assumes decay through the γγ, ττ , ZZ and W+W− channels. In all cases considered we identify the 68% and 95% credible posterior probability regions in a Bayesian approach. We find that, when the constraints are applied with their respective uncertainties, the first case shows strong CMSSM-like behavior, with the stau coannihilation region featuring highest posterior probability, the best-fit point, a correct mass of the lightest Higgs boson and the lighter stop mass in the ballpark of 1 TeV. We also expose in this region a linear relationship between the trilinear couplings of the stau and the stop, with both of them being strongly negative as enforced by the Higgs mass and the relic density, which outside of the stau coannihilation region show some tension. The second and the third case, on the other hand, while allowed are disfavored by the constraints from direct detection of dark matter and from BR (Bs → μ+μ−). Without the anomalous magnetic moment of the muon the fit improves considerably, especially for negative effective μ parameter. We discuss how the considered scenarios could be tested further at the LHC and in dark matter searches. ∗On leave of absence from the University of Sheffield, UK. 1 ar X iv :1 21 1. 16 93 v3 [ he pph ] 2 9 M ay 2 01 3

A light NMSSM pseudoscalar Higgs boson at the LHC redux

A bstractThe Next-to-Minimal Supersymmetric Standard Model (NMSSM) contains a singlet-like pseudoscalar Higgs boson in addition to the doublet-like pseudoscalar of the Minimal Supersymmetric Standard Model. This new pseudoscalar can have a very low mass without violating the LEP exclusion constraints and it can potentially provide a hallmark signature of non-minimal supersymmetry at the LHC. In this analysis we revisit the light pseudoscalar in the NMSSM with partial universality at some high unification scale. We delineate the regions of the model’s parameter space that are consistent with the up-to-date theoretical and experimental constraints, from both Higgs boson searches and elsewhere (most notably b-physics), and examine to what extent they can be probed by the LHC. To this end we review the most important production channels of such a Higgs state and assess the scope of its observation at the forthcoming Run-2 of the LHC. We conclude that the bb¯

Di-photon Higgs signals at the LHC in the next-to-minimal supersymmetric standard model

b\overline{b}

Novel Higgs-to-125 GeV Higgs boson decays in the complex NMSSM

-associated production of the pseudoscalar, which has been emphasised in previous studies, does not carry much promise anymore, given the measured mass of the Higgs boson at the LHC. However, the decays of one of the heavier scalar Higgs bosons of the NMSSM can potentially lead to the discovery of its light pseudoscalar. Especially promising are the decays of one or both of the two lightest scalar states into a pseudoscalar pair and of the heaviest scalar into a pseudoscalar and a Z boson. Since the latter channel has not been explored in detail in the literature so far, we provide details of some benchmark points which can be probed for establishing its signature.

Explicit CP Violation in the MSSM Through Higgs ---> gamma gamma

We scan the parameter space of the NMSSM for the observability of a Higgs boson at the LHC with 300 {\rm fb}^{-1} integrated luminosity per detector, taking the present LEP constraints into account. We focus on the regions of parameter space for which none of the usually considered LHC detection modes are viable due to the fact that the only light non-singlet (and, therefore, potentially visible) Higgs boson, h, decays mainly to two CP-odd light Higgs bosons, h\to aa. We simulate the WW\to h \to aa detection mode. We find that this signal may be detectable at the LHC as a signal/background \sim 600/600 bump in the tail of a rapidly falling mass distribution. If further study gives us confidence that the shape of the background tail is predictable, then we can conclude that NMSSM Higgs detection at the LHC will be possible throughout all of parameter space by combining this signal with the usual detection modes previously simulated by ATLAS and CMS. We also show that this WW\to h\to aa signal will be highly visible at the LC due to its cleaner environment and high luminosity. We present a study of the production modes and decay channels of interest at the LC.

Exploring the di-photon decay of a light Higgs boson in the MSSM with explicit CP violation

The NMSSM contains a Higgs singlet in addition to the two Higgs doublets typical of the MSSM, thus resulting in a total of seven physical Higgs mass states. Therefore, the phenomenology of the NMSSM Higgs sector can differ considerably from that of the MSSM, and there are good prospects of finding in regions of the NMSSM parameter space Higgs signals that cannot be reproduced in the MSSM. We examined here the two-photon decay mode of a Higgs boson and found that up to three neutral Higgs states, heavy and/or light, could be simultaneously observable at the LHC, a possibility precluded to the MSSM. There are also some possibilities that only the lightest NMSSM Higgs boson be detectable via this mode, with a mass beyond the upper limit of the corresponding MSSM state, thus also allowing one to distinguish between the two scenarios. However, in most of the NMSSM parameter space the configurations of the non-minimal model are not very different from those arising in the minimal case.

Two Higgs Bosons near 125 GeV in the Complex NMSSM and the LHC Run I Data

While the properties of the 125 GeV Higgs boson-like particle observed by the ATLAS and CMS collaborations are largely compatible with those predicted for the Standard Model state, significant deviations are present in some cases. We, therefore, test the viability of a Beyond the Standard Model scenario based on Supersymmetry, the CP-violating Next-to-Minimal Supersymmetric Standard Model, against the corresponding experimental observations. Namely, we identify possible model configurations in which one of its Higgs bosons is consistent with the LHC observation and evaluate the role of the explicit complex phases in both the mass and di-photon decay of such a Higgs boson. Through a detailed analysis of some benchmark points corresponding to each of these configurations, we highlight the impact of the CP-violating phases on the model predictions compared to the CP-conserving case.