Rencontres de Moriond EW 2012: Impact of a Higgs boson on supersymmetry

Yesterday at the Moriond conference, several theorists addressed the consequences of the current Higgs boson searches on models going beyond the Standard Model.


Nazila Farvah Mahmoudi from CERN presented a study on the impact of a Higgs boson at 125 GeV on various supersymmetry (SUSY) models. So what would happen if indeed there is a Standard Model Higgs between 123 GeV and 127 GeV? The results are stunning: If all the recent limits from flavor physics are included, like the latest Bs to two muons measurement from LHCb, the limits from CMS on direct searches for SUSY, and assuming maximal mixing, then only a narrow band at low value of tan beta - one of the key parameters in SUSY - at or lower than 5 survive. At this value, mA, the mass of one of the five Higgs bosons predicted by SUSY, should be found between 200 and 500 GeV.

This study done in collaboration with A. Arbey, M. Battaglia, A. Djouadi and J. Quévillon used the pMSSM model, a supersymmetric model with 19 free parameters. Plain SUSY has 105 free parameters so it would not have been possible to let them all vary freely. Already, they had to scan 40 million points in this 19-parameter space and imposed new constraints from the LHC plus some established by other experiments.“The limits imposed on all these models by the Higgs boson mass are much stronger than by any other direct measurements,” said Nazila. This study rules out the Anomaly Mediated SUSY Breaking  (AMSB) and Gauge Mediated SUSY Breaking (GMSB) in their minimal versions.

At this point, all searches for SUSY at least those presented by CMS (ATLAS presentation is scheduled for Friday) have revealed nothing in excess of the Standard Model background, as was reported this morning by Steven Lowette from University of California in Santa Barbara.

Clearly, we can only expect the best out of the coming year!


The yellow line shows what has been excluded by CMS searches for SUSY. Everything below is still allowed.

by Pauline Gagnon