Likelihood analysis of the pMSSM11 in light of LHC 13-TeV data

Abstract

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 $$\sim 36$$ ∼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 $$(g-2)_\mu $$ (g-2)μ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses $$M_{1,2,3}$$ M1,2,3 , a common mass for the first-and second-generation squarks $$m_{\tilde{q}}$$ mq~ and a distinct third-generation squark mass $$m_{\tilde{q}_3}$$ mq~3 , a common mass for the first-and second-generation sleptons $$m_{\tilde{\ell }}$$ mℓ~ and a distinct third-generation slepton mass $$m_{\tilde{\tau }}$$ mτ~ , a common trilinear mixing parameter A, the Higgs mixing parameter $$\mu $$ μ , the pseudoscalar Higgs mass $$M_A$$ MA and $$\tan \beta $$ tanβ . In the fit including $$(g-2)_\mu $$ (g-2)μ , a Bino-like $$\tilde{\chi }^0_{1}$$ χ~10 is preferred, whereas a Higgsino-like $$\tilde{\chi }^0_{1}$$ χ~10 is mildly favoured when the $$(g-2)_\mu $$ (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, $$\tilde{\chi }^0_{1}$$ χ~10 , into the range indicated by cosmological data. In the fit including $$(g-2)_\mu $$ (g-2)μ , coannihilations with $$\tilde{\chi }^0_{2}$$ χ~20 and the Wino-like $$\tilde{\chi }^\pm _{1}$$ χ~1± or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the $$\tilde{\chi }^0_{2}$$ χ~20 and the Higgsino-like $$\tilde{\chi }^\pm _{1}$$ χ~1± or with first- and second-generation squarks may be important when the $$(g-2)_\mu $$ (g-2)μ constraint is dropped. In the two cases, we present $$\chi ^2$$ 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 $$(g-2)_\mu $$ (g-2)μ constraint, as well as for discovering electroweakly-interacting sparticles at a future linear $$e^+ e^-$$ e+e- collider such as the ILC or CLIC.