Non-thermal CMSSM with a 125 GeV Higgs

TL;DR

The paper investigates non-thermal dark matter within the CMSSM/mSUGRA framework by introducing a reheating temperature $T_R$ from modulus decay as an additional parameter. Requiring a 125 GeV Higgs, proper radiative electroweak symmetry breaking, and no dark matter overproduction, the study finds that a Higgsino-like LSP with mass around 300 GeV can saturate the Planck DM abundance only for $T_R\approx 2$ GeV; larger $T_R$ values necessitate a multi-component DM scenario or DM underproduction. The surviving spectra feature heavy sfermions and gluinos at the multi-TeV scale (2–7 TeV) with near-degenerate lightest neutralinos and charginos, making LHC discovery challenging but motivating future 100 TeV colliders and next-generation direct-detection experiments (e.g., LUX/XENON1T). Indirect constraints from Fermi and direct detection from LUX strongly shape the viable parameter space, particularly disfavouring low $T_R$ unless the LSP is nearly purely Higgsino. The results tie the non-thermal CMSSM to sequestered SUSY-breaking string models, highlighting a tightly constrained but testable region of parameter space at the intersection of collider and astroparticle experiments.

Abstract

We study the phenomenology of the CMSSM/mSUGRA with non-thermal neutralino dark matter. Besides the standard parameters of the CMSSM we include the reheating temperature as an extra parameter. Imposing radiative electroweak symmetry breaking with a Higgs mass around 125 GeV and no dark matter overproduction, we contrast the scenario with different experimental bounds from colliders (LEP, LHC), cosmic microwave background (Planck), direct (LUX, XENON100, CDMS, IceCube) and indirect (Fermi) dark matter searches. The allowed parameter space is characterised by a Higgsino-like LSP with a mass around 300 GeV. The observed dark matter abundance can be saturated for reheating temperatures around 2 GeV while larger temperatures require extra non-neutralino dark matter candidates and extend the allowed parameter space. Sfermion and gluino masses are in the few TeV region. These scenarios can be achieved in string models of sequestered supersymmetry breaking which avoid cosmological moduli problems and are compatible with gauge coupling unification. Astrophysics and particle physics experiments will fully investigate this non-thermal scenario in the near future.

Figures (13)

• Figure 1: Correlation between $a=m/M$ and $b=A/M$ for different LSP compositions (left) and DM thermal relic densities (right) in the region where the LSP is at least 10% Higgsino.
• Figure 2: Correlation between $a=m/M$ and $b=A/M$ for different values of $\tan\beta$ (left) and gaugino mass (right) in the region where the LSP is at least 10% Higgsino.
• Figure 3: Correlation between $a=m/M$ and $b=A/M$ for different values of the averaged stop mass $M_{\rm SUSY}$ (left) and the Higgs mass (right) in the region where the LSP is at least 10% Higgsino.
• Figure 4: Case with $\mu>0$: $m/M$ vs $A/M$ after imposing LEP, LHC, Planck and Fermi constraints (left) and corresponding LSP composition (right) for $m_h = 125.5$ - $126$ GeV and $T_R = 2, 10$ GeV.
• Figure 5: Case with $\mu>0$: correlation between $a=m/M$ and $b=A/M$ after imposing LEP, LHC, Planck and Fermi (pass 8 limit) constraints with the corresponding spin independent (left) and spin dependent (right) WIMP-nucleon cross section for $m_h = 125.5$ GeV and $T_R = 10$ GeV.