Likelihood analysis of the sub-GUT MSSM in light of LHC 13-TeV data

The European Physical Journal C, Feb 2018

We describe a likelihood analysis using MasterCode of variants of the MSSM in which the soft supersymmetry-breaking parameters are assumed to have universal values at some scale $M_\mathrm{in}$ below the supersymmetric grand unification scale $M_\mathrm{GUT}$, as can occur in mirage mediation and other models. In addition to $M_\mathrm{in}$, such ‘sub-GUT’ models have the 4 parameters of the CMSSM, namely a common gaugino mass $m_{1/2}$, a common soft supersymmetry-breaking scalar mass $m_0$, a common trilinear mixing parameter A and the ratio of MSSM Higgs vevs $\tan \beta$, assuming that the Higgs mixing parameter $\mu > 0$. We take into account constraints on strongly- and electroweakly-interacting sparticles from $\sim 36$/fb of LHC data at 13 TeV and the LUX and 2017 PICO, XENON1T and PandaX-II searches for dark matter scattering, in addition to the previous LHC and dark matter constraints as well as full sets of flavour and electroweak constraints. We find a preference for $M_\mathrm{in}\sim 10^5$ to $10^9 \,\, \mathrm {GeV}$, with $M_\mathrm{in}\sim M_\mathrm{GUT}$ disfavoured by $\Delta \chi ^2 \sim 3$ due to the $\mathrm{BR}(B_{s, d} \rightarrow \mu ^+\mu ^-)$ constraint. The lower limits on strongly-interacting sparticles are largely determined by LHC searches, and similar to those in the CMSSM. We find a preference for the LSP to be a Bino or Higgsino with $m_{\tilde{\chi }^0_{1}} \sim 1 \,\, \mathrm {TeV}$, with annihilation via heavy Higgs bosons H / A and stop coannihilation, or chargino coannihilation, bringing the cold dark matter density into the cosmological range. We find that spin-independent dark matter scattering is likely to be within reach of the planned LUX-Zeplin and XENONnT experiments. We probe the impact of the $(g-2)_\mu$ constraint, finding similar results whether or not it is included.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-018-5633-3.pdf

J. C. Costa, E. Bagnaschi, K. Sakurai, M. Borsato, O. Buchmueller, M. Citron, A. De Roeck, M. J. Dolan, J. R. Ellis, H. Flächer, S. Heinemeyer, M. Lucio, D. Martínez Santos, K. A. Olive, A. Richards, G. Weiglein. Likelihood analysis of the sub-GUT MSSM in light of LHC 13-TeV data, The European Physical Journal C, 2018, 158, DOI: 10.1140/epjc/s10052-018-5633-3