Sparticle spectroscopy and dark matter in a U(1) B-L extension of MSSM

Abstract

We consider a class of SUSY models in which the MSSM gauge group is supplemented with a gauged U(1)(B-L) symmetry and a global U(1)(R) symmetry. This extension introduces only electrically neutral states, and the new SUSY partners effectively double the number of states in the neutralino sector that now includes a blino (from B - L) and singlino from a gauge singlet superfield. If the DM density is saturated by a LSP neutralino, the model yields quite a rich phenomenology depending on the DM composition. The LSP relic density constraint provides a lower bound on the stop and gluino masses of about 3 TeV and 4 TeV respectively, which is testable in the near future collider experiments such as HL-LHC. The chargino mass lies between 0.24 TeV and about 2.0 TeV, which can be tested based on the allowed decay channels. We also find m tau</mml:mover>1 greater than or similar to 500 GeV, and me</mml:mover>,m mu</mml:mover>,mv</mml:mover>S,P greater than or similar to 1 TeV. We identify chargino-neutralino coannihilation processes in the mass region 0.24 TeV less than or similar to m chi <mml:mo stretchy="true"></mml:mover>10</mml:msubsup><mml:mo>approximate to <mml:msub>m<mml:mover accent="true">chi <mml:mo stretchy="true"></mml:mover>1<mml:mo>+/- <mml:mo>less than or similar to 1.5 TeV, and also coannihilation processes involving stau, selectron, smuon and sneutrinos for masses around 1 TeV. In addition, A(2) resonance solutions are found around 1 TeV, and H-2 and H-3 resonance solutions are also shown around 0.5 TeV and 1 TeV . Some of the A(2) resonance solutions with tan beta greater than or similar to 20 may be tested by the A/H -> tau (+)tau (-) LHC searches.. While the relic density constraint excludes the bino-like DM, it is still possible to realize higgsino, singlino and blino-like DM for various mass scales. We show that all these solutions will be tested in future direct detection experiments such as LUX-Zeplin and Xenon-nT.