MSSM Interpretations of the LHC Discovery: Light or Heavy Higgs?

TL;DR

This paper explores whether the 126 GeV Higgs-like particle discovered at the LHC can be interpreted within the MSSM framework as either the light or heavy CP-even Higgs, fitting experimental data with good accuracy.

Contribution

It provides a comprehensive fit of LHC and Tevatron data within the MSSM, comparing light and heavy Higgs interpretations and highlighting the potential for additional Higgs signatures.

Findings

The light Higgs MSSM interpretation has a higher fit probability than the SM.

Both light and heavy MSSM Higgs scenarios are compatible with current data.

The fits suggest possible signatures of additional Higgs states in future experiments.

Abstract

A Higgs-like particle with a mass of about 126 GeV has been discovered at the LHC. Within the experimental uncertainties, the measured properties of this new state are compatible with those of the Higgs boson in the Standard Model (SM). While not statistically significant at present, the results show some interesting patterns of deviations from the SM predictions, in particular a higher rate in the \gamma\gamma\ decay mode observed by ATLAS and CMS, and a somewhat smaller rate in the \tau\tau\ mode. The LHC discovery is also compatible with the predictions of the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM), interpreting the new state as either the light or the heavy CP-even MSSM Higgs boson. Within the framework of the MSSM with seven free parameters (pMSSM-7), we fit the various rates of cross section times branching ratio as measured by the LHC and Tevatron experiments under the hypotheses of either the light or the heavy CP-even Higgs boson being the new state around 126 GeV, with and without the inclusion of further low-energy observables. We find an overall good quality of the fits, with the best fit points exhibiting an enhancement of the \gamma\gamma rate, as well as a small suppression of the bb and \tau\tau\ channels with respect to their SM expectations, depending on the details of the fit. For the fits including the whole data set the light CP-even Higgs interpretation in the MSSM results in a higher relative fit probability than the SM fit. On the other hand, we find that the present data also permit the more exotic interpretation in terms of the heavy CP-even MSSM Higgs, which could give rise to experimental signatures of additional Higgs states in the near future.