Sleptonic SUSY: from UV framework to IR phenomenology

Abstract

We study an attractive scenario, “Sleptonic SUSY”, which reconciles the 125 GeV Higgs scalar and the non-observation of superpartners thus far with potentially pivotal roles for slepton phenomenology: providing viable ongoing targets for LHC discovery, incorporating a co-annihilation partner for detectable thermal relic dark matter, and capable of mediating the potential muon g − 2 anomaly. This is accomplished by a modestly hierarchical spectrum, with sub-TeV sleptons and electroweakinos and with multi-TeV masses for the other new states. We study new elements in the UV MSSM realization of Sleptonic SUSY based on higher-dimensional sequestering and the synergy between the resulting gaugino-mediation, hypercharge D-term mediation and Higgs-mediation of SUSY-breaking, so as to more fully capture the range of possibilities. This framework stands out by harmoniously solving the flavor, CP and μ − Bμ problems of the supersymmetric paradigm. We discuss its extension to orbifold GUTs, including gauge-coupling and b-tau unification. We also develop a non-minimal model with extra Higgs fields, in which the electroweak vacuum is more readily cosmologically stable against decay to a charge-breaking vacuum, allowing a broader range of sleptonic spectra than in the MSSM alone. We survey the rich set of signals possible at the LHC and future colliders, covering both R-parity conservation and violation, as well as for dark matter detection. While the multi-TeV squarks imply a Little Hierarchy Problem, intriguingly, small changes in parameter space to improve naturalness result in dramatic phase transitions to either electroweak-preservation or charge-breaking. In a Multiverse setting, the modest unnaturalness may then be explained by the “principle of living dangerously”.

Report of the Topical Group on Physics Beyond the Standard Model at Energy Frontier for Snowmass 2021

“…While null-results from SUSY searches at the LHC have long excluded strongly charged sparticles (such as gluinos and squarks) in this mass range, LHC searches only recently began putting strong constraints on this range of m for sparticles that interact only electroweakly such as the electroweakinos and smuons that could explain the g-2 anomaly [87,88], and these bounds should improve with further analyses of existing LHC Run2 data as well as with the Run3 data to be recorded in the next years. Future lepton colliders also play an important role for probing electroweak sparticles, especially for (semi-)compressed spectra [89][90][91][92][93][94][95][96][97][98][99][100]. It is worth noting that explanations of the muon g-2 anomalies in the MSSM suggest electroweakinos in the few-hundred GeV mass range, a parameter region of the MSSM yielding viable dark matter candidates [82][83][84][85].…”

Speculations on the W-mass measurement at CDF*

“…δG F At one-loop order, many operators will be generated. Those most constrained are also relevant for our discussion here, in particular for the S-T-fit, as [50] 95…”

Flavor- and CP-safe explanation of gμ − 2 anomaly

“…2 An important theoretical consideration, which we do not consider here, is can g µ −2 be explained in models consistent with grand unification. It was shown that, at least in some unification models, it can be rectified [14,[28][29][30][31].…”

“…The CP-problem is solved by assuming a shift symmetry where the imaginary part of the SUSY breaking field receives a constant shift [38]. See also [31] for another construction of a CP-safe gaugino mediation model. 5 In ref.…”