The new look pMSSM with neutralino and gravitino LSPs

• Published in: The European physical journal. C, Particles and fields Vol. 72; no. 9; pp. 1 - 26
• Main Authors: Cahill-Rowley, Matthew W., Hewett, JoAnne L., Hoeche, Stefan, Ismail, Ahmed, Rizzo, Thomas G.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2012; Springer; Springer Nature B.V
• Subjects: Astronomy; Astrophysics and Cosmology; Big bang cosmology; Computer simulation; Elementary Particles; Exact sciences and technology; Hadrons; Heavy Ions; Large Hadron Collider; Luminosity; Mathematical models; Measurement Science and Instrumentation; Nuclear Energy; Nuclear fusion; Nuclear Physics; Nuclei (nuclear physics); Parameters; Phenomenology; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Regular Article - Theoretical Physics; Searching; String Theory; The physics of elementary particles and fields; Light Neutralino; Gravitino Mass; Minimal Supersymmetric Standard Model; Light Supersymmetric Particle; Dark Matter; Atlas; LHC collider; Nucleosynthesis; Luminosity; Quarks; Neutralino; Big bang; Elementary particles; Cosmology; Collision energy; Models; Sparticles; Gravitinos; Mathematical physics
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-012-2156-1

The pMSSM provides a broad perspective on SUSY phenomenology. In this paper we generate two new, very large, sets of pMSSM models with sparticle masses extending up to 4 TeV, where the lightest supersymmetric particle (LSP) is either a neutralino or gravitino. The existence of a gravitino LSP necessitates a detailed study of its cosmological effects and we find that Big Bang Nucleosynthesis places strong constraints on this scenario. Both sets are subjected to a global set of theoretical, observational and experimental constraints resulting in a sample of ∼225k viable models for each LSP type. The characteristics of these two model sets are briefly compared. We confront the neutralino LSP model set with searches for SUSY at the 7 TeV LHC using both the missing (MET) and non-missing E T ATLAS analyses. In the MET case, we employ Monte Carlo estimates of the ratios of the SM backgrounds at 7 and 8 TeV to rescale the 7 TeV data-driven ATLAS backgrounds to 8 TeV. This allows us to determine the pMSSM parameter space coverage for this collision energy. We find that an integrated luminosity of ∼5–20 fb −1 at 8 TeV would yield a substantial increase in this coverage compared to that at 7 TeV and can probe roughly half of the model set. If the pMSSM is not discovered during the 8 TeV run, then our model set will be essentially void of gluinos and lightest first and second generation squarks that are ≲700–800 GeV, which is much less than the analogous mSUGRA bound. Finally, we demonstrate that non-MET SUSY searches continue to play an important role in exploring the pMSSM parameter space. These two pMSSM model sets can be used as the basis for investigations for years to come.