Likelihood Analysis of the pMSSM11 in Light of LHC 13-TeV Data

Abstract

We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from ~ 36/fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the $(g-2{)}_{\hat{I}}¼$ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses $M_{1,2,3}$, a common mass for the first-and second-generation squarks $m_{\tilde{q}}$ and a distinct third-generation squark mass $m_{{\tilde{q}}_3}$, a common mass for the first-and second-generation sleptons $m_{\tilde{l}}$ and a distinct third-generation slepton mass $m_{\tilde{\ddot{I}}„}$, a common trilinear mixing parameter $A$, the Higgs mixing parameter $\hat{I}¼$, the pseudoscalar Higgs mass $M_A$ and $\tan {\hat{I}}^2$. In the fit including $(g-2{)}_{\hat{I}}¼$, a Bino-like $\tilde{\ddot{I}}{‡}_1^0$ is preferred, whereas a Higgsino-like $\tilde{\ddot{I}}{‡}_1^0$ is favoured when the $(g-2{)}_{\hat{I}}¼$ constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, $\tilde{\ddot{I}}{‡}_1^0$, into the range indicated by cosmological data. In the fit including $(g-2{)}_{\hat{I}}¼$, coannihilations with $\tilde{\ddot{I}}{‡}_2^0$ and the Wino-like $\tilde{\ddot{I}}{‡}_1^{\pm }$ or with nearly-degenerate first- and second-generation sleptons are favoured, whereas coannihilations with the $\tilde{\ddot{I}}{‡}_2^0$ and the Higgsino-like $\tilde{\ddot{I}}{‡}_1^{\pm }$ or with first- and second-generation squarks may be important when the $(g-2{)}_{\hat{I}}¼$ constraint is dropped. Prospects remain for discovering strongly-interacting sparticles at the LHC as well as for discovering electroweakly-interacting sparticles at a future linear $e^{+}{e}^{-}$ collider such as the ILC or CLIC.

48 pages, 24 figures, 65 plots, 6 tables; version published on EPJC