Some necessary conditions for allowing the PQ scale as high as M GUT in SUSY models with an axino or neutralino LSP

2011/04/30 by Howard Baer, Andre Lessa · 1 citation
Computer Science · Physics and Astronomy · #Axion #Computational Physics and Python Applications #Context (archaeology) #Dark Matter and Cosmic Phenomena #Dark matter #Gravitino #Neutralino #Particle physics theoretical and experimental studies #Strong CP problem #Supersymmetry #astro-ph.HE #hep-ph

paper · pdf · doi:10.1007/jhep06(2011)027

29 pages including 14 .eps figures

arxiv created 2011/05/25 · openalex publication_date 2011/06/01 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We examine some conditions which are needed to allow the Peccei-Quinn scale (f_a) as high as the SUSY GUT scale (M_GUT ∼ 10¹⁶ GeV) in the context of the PQMSSM with either an axino or a neutralino LSP. The main problem in non-SUSY models with f_a∼ M_GUT is the generation of an overabundance of axion dark matter (∼ f_a^7/6) due to vacuum misalignment. We show that once all the components of the axion supermultiplet are included, the upper limit on f_a can be evaded due to large entropy injection from saxion decays. This large entropy injection also dilutes all other quasi-stable relic densities, naturally evading the BBN constraints and solving the gravitino problem. We find that f_a∼ M_GUT can be allowed by relic density/BBN constraints provided that the saxion mass m_s> 50 TeV, the initial saxion field value is of order of the PQ scale and the initial axion mis-alignment angle θ_i\alt 0.05 . These restrictions can be considerably loosened for f_a∼ 10¹⁵ GeV. The allowed range for the re-heat temperature (T_R) is strongly dependent on the nature of the LSP. For the axino LSP, T_R \gtrsim 10⁸ GeV, while for neutralino LSP any value is allowed. In the latter case, f_a∼ M_GUT can be more easily accommodated than in the axino LSP scenario. For f_a∼ M_GUT in SUSY models, the dark matter abundance should be dominated by axions, albeit with mass m_a∼ 10^-10 eV, far below the region currently probed by experiment.

Citations

• Massive particle decay and cold dark matter abundance
• Effective supersymmetry at the LHC
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• QCD and instantons at finite temperature
• LEPTOGENESIS AS THE ORIGIN OF MATTER
• Yukawa coupling unification in supersymmetric models
• Axino mass

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• Dark radiation constraints on mixed Axion/Neutralino dark matter