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

We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from $\sim 36$ /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)_\mu $ 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 $m_{\tilde{\ell }}$ and a distinct third-generation slepton mass $m_{\tilde{\tau }}$ , a common trilinear mixing parameter A, the Higgs mixing parameter $\mu $ , the pseudoscalar Higgs mass $M_A$ and $\tan \beta $ . In the fit including $(g-2)_\mu $ , a Bino-like $\tilde{\chi }^0_{1}$ is preferred, whereas a Higgsino-like $\tilde{\chi }^0_{1}$ is mildly favoured when the $(g-2)_\mu $ 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, $\tilde{\chi }^0_{1}$ , into the range indicated by cosmological data. In the fit including $(g-2)_\mu $ , coannihilations with $\tilde{\chi }^0_{2}$ and the Wino-like $\tilde{\chi }^\pm _{1}$ or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the $\tilde{\chi }^0_{2}$ and the Higgsino-like $\tilde{\chi }^\pm _{1}$ or with first- and second-generation squarks may be important when the $(g-2)_\mu $ constraint is dropped. In the two cases, we present $\chi ^2$ functions in two-dimensional mass planes as well as their one-dimensional profile projections and best-fit spectra. Prospects remain for discovering strongly-interacting sparticles at the LHC, in both the scenarios with and without the $(g-2)_\mu $ constraint, as well as for discovering electroweakly-interacting sparticles at a future linear $e^+ e^-$ collider such as the ILC or CLIC.