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) μ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses M1 , 2 , 3, a common mass for the first-and second-generation squarks mq~ and a distinct third-generation squark mass mq~3, a common mass for the first-and second-generation sleptons mℓ~ and a distinct third-generation slepton mass mτ~, a common trilinear mixing parameter A, the Higgs mixing parameter μ, the pseudoscalar Higgs mass MA and tan β. In the fit including (g- 2) μ, a Bino-like χ~10 is preferred, whereas a Higgsino-like χ~10 is mildly favoured when the (g- 2) μ 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, χ~10, into the range indicated by cosmological data. In the fit including (g- 2) μ, coannihilations with χ~20 and the Wino-like χ~1± or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the χ~20 and the Higgsino-like χ~1± or with first- and second-generation squarks may be important when the (g- 2) μ constraint is dropped. In the two cases, we present χ2 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) μ constraint, as well as for discovering electroweakly-interacting sparticles at a future linear e+e- collider such as the ILC or CLIC.