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1.
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Non-universal SUSY models, $g_\mu -2$, $m_H$ and dark matter
/ Ellis, John (King's Coll. London ; CERN) ; Olive, Keith A. (Minnesota U.) ; Spanos, Vassilis C. (Minnesota U. ; Athens U.)
We study the anomalous magnetic moment of the muon, $g_\mu - 2 \equiv 2 a_\mu$, in the context of supersymmetric models beyond the CMSSM, where the unification of either the gaugino masses $M_{1,2,3}$ or sfermion and Higgs masses is relaxed, taking into account the measured mass of the Higgs boson, $m_H$, the cosmological dark matter density and the direct detection rate. We find that the model with non-unified gaugino masses can make a contribution $\Delta a_\mu\sim 20 \times 10^{-10}$ to the anomalous magnetic moment of the muon, for example if $M_{1,2} \sim 600$ GeV and $M_3\sim 8$ TeV. [...]
arXiv:2407.08679; KCL-PH-TH/2024-41; CERN-TH-2024-109; UMN-TH-4325/24; FTPI-MINN-24/16.-
2024-10-28 - 22 p.
- Published in : Eur. Phys. J. C 84 (2024) 1121
Fulltext: 2407.08679 - PDF; document - PDF;
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2.
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The CMSSM Survives Planck, the LHC, LUX-ZEPLIN, Fermi-LAT, H.E.S.S. and IceCube
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; Olive, Keith A. (Minnesota U.) ; Spanos, Vassilis C. (Athens Natl. Capodistrian U.) ; Stamou, Ioanna D. (Brussels U.)
We revisit the viability of the CMSSM, searching for regions of parameter space that yield a neutralino dark matter density compatible with Planck measurements, as well as LHC constraints including sparticle searches and the mass of the Higgs boson, recent direct limits on spin-independent and -dependent dark matter scattering from the LUX-ZEPLIN (LZ) experiment, the indirect constraints from Fermi-LAT and H.E.S.S. on dark matter annihilations to photons in dwarf spheroidal galaxies and the Galactic Centre, and the IceCube limits on muons from annihilations to neutrinos in the Sun. [...]
arXiv:2210.16337; KCL-PH-TH/2022-52; CERN-TH-2022-172; UMN-TH-4204/22; FTPI-MINN-22/29.-
2023-03-23 - 41 p.
- Published in : Eur. Phys. J. C 83 (2023) 246
Fulltext: document - PDF; 2210.16337 - PDF;
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4.
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On Gravitino properties in a Conformal Supergravity Model
/ Mavromatos, Nick E. (King's Coll. London ; CERN) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
In the context of a conformal Supergravity (SUGRA) model in the Einstein frame, in which the (next to) minimal supersymmetric standard model can embedded naturally to produce chaotic inflation scenarios, we study properties of gravitino in the cases where it is stable or unstable. In the latter case, we demonstrate that for large dilaton scale factors there is an enhanced magnitude of the gravitino width, when it decays to neutralino dark matter, as compared with the standard SUGRA case. [...]
KCL-PH-TH-2013-01; LCTS-2012-34; arXiv:1212.6386; KCL-PH-TH-2013-01; LCTS-2012-34.-
2013
- Published in : Phys. Rev. D 87 (2013) 035025
APS published version, local copy: PDF; Fulltext: PDF; External link: Preprint
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5.
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Metastable Charged Sparticles and the Cosmological Li7 Problem
/ Cyburt, Richard H. (Michigan State U. ; Michigan State U., NSCL ; Michigan State U., JINA) ; Ellis, John (CERN ; King's Coll. London) ; Fields, Brian D. (Illinois U., Urbana, Astron. Dept.) ; Luo, Feng (Minnesota U. ; King's Coll. London) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst. ; Minnesota U.) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
We consider the effects of metastable charged sparticles on Big-Bang Nucleosynthesis (BBN), including bound-state reaction rates and chemical effects. We make a new analysis of the bound states of negatively-charged massive particles with the light nuclei most prominent in BBN, and present a new code to track their abundances, paying particular attention to that of Li7. [...]
arXiv:1209.1347; KCL-PH-TH-2012-36; LCTS-2012-18; CERN-PH-TH-2012-223; FTPI-MINN-12-29; UMN-TH-3117-12; KCL-PH-TH-2012-36; LCTS-2012-18; CERN-PH-TH-2012-223; UMN-TH-3117-12; FTPI-MINN-12-29.-
2012 - 49 p.
- Published in : JCAP 12 (2012) 037
Fulltext: PDF; IOP Open Access article: PDF; External link: Preprint
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6.
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An Enhanced Cosmological Li6 Abundance as a Potential Signature of Residual Dark Matter Annihilations
/ Ellis, John (King's Coll. London ; CERN) ; Fields, Brian D. (Illinois U., Urbana, Astron. Dept. ; Illinois U., Urbana) ; Luo, Feng (Minnesota U.) ; Olive, Keith A. (Minnesota U. ; Minnesota U., Theor. Phys. Inst.) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
Residual late-time dark matter particle annihilations during and after Big Bang Nucleosynthesis (BBN) may alter the predicted cosmological abundances of the light elements. Within the constrained minimal supersymmetric extension of the Standard Model (the CMSSM) with a neutralino LSP, we find negligible effects on the abundances of Deuterium, He3, He4 and Li7 predicted by homogeneous BBN, but potentially a large enhancement in the predicted abundance of Li6. [...]
arXiv:1109.0549; KCL-PH-TH-2011-26; LCTS-2011-12; CERN-PH-TH-2011-205; FTPI-MINN-11-19; UMN-TH-3009-11; KCL-PH-TH-2011-26; LCTS-2011-12; CERN-PH-TH-2011-205; UMN-TH-3009-11; FTPI-MINN-11-19.-
2011 - 24 p.
- Published in : Phys. Rev. D 84 (2011) 123502
APS Published version, local copy: PDF; Fulltext: PDF; External link: Preprint
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7.
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Galactic-Centre Gamma Rays in CMSSM Dark Matter Scenarios
/ Ellis, John (CERN ; King's Coll. London) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst. ; Minnesota U.) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
We study the production of gamma rays via LSP annihilations in the core of the Galaxy as a possible experimental signature of the constrained minimal supersymmetric extension of the Standard Model (CMSSM), in which supersymmetry-breaking parameters are assumed to be universal at the GUT scale, assuming also that the LSP is the lightest neutralino chi. The part of the CMSSM parameter space that is compatible with the measured astrophysical density of cold dark matter is known to include a stau_1 - chi coannihilation strip, a focus-point strip where chi has an enhanced Higgsino component, and a funnel at large tanb where the annihilation rate is enhanced by the poles of nearby heavy MSSM Higgs bosons, A/H. [...]
CERN-PH-TH-2011-130; KCL-PH-TH-2011-13; LCTS-2011-02; FTPI-MINN-11-14; UMN-TH-3004-11; arXiv:1106.0768; CERN-PH-TH-2011-130; KCL-PH-TH-2011-13; LCTS-2011-02; UMN-TH-3004-11; FTPI-MINN-11-14.-
2011 - 33 p.
- Published in : JCAP 10 (2011) 024
Preprint: PDF; External link: Preprint
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8.
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Neutrino fluxes from nonuniversal Higgs mass LSP annihilations in the Sun
/ Ellis, John (CERN ; King's Coll. London) ; Olive, Keith A. (Minnesota U. ; Stanford U., Phys. Dept. ; SLAC) ; Savage, Christopher (Stockholm U., OKC) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
We extend our previous studies of the neutrino fluxes expected from neutralino LSP annihilations inside the Sun to include variants of the minimal supersymmetric extension of the Standard Model (MSSM) with squark, slepton and gaugino masses constrained to be universal at the GUT scale, but allowing one or two non-universal supersymmetry-breaking parameters contributing to the Higgs masses (NUHM1,2). As in the constrained MSSM (CMSSM) with universal Higgs masses, there are large regions of the NUHM parameter space where the LSP density inside the Sun is not in equilibrium, so that the annihilation rate may be far below the capture rate, and there are also large regions where the capture rate is not dominated by spin-dependent LSP-proton scattering. [...]
arXiv:1102.1988; CERN-PH-TH-2011-025; KCL-PH-TH-2011-03; UMN-TH-2936-11; FTPI-MINN-11-03; SLAC-PUB-14372.-
2011 - 22 p.
- Published in : Phys. Rev. D 83 (2011) 085023
APS Published version, local copy: PDF; Fulltext: PDF; External link: Preprint
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9.
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Nuclear Reaction Uncertainties, Massive Gravitino Decays and the Cosmological Lithium Problem
/ Cyburt, Richard H. (Michigan State U., JINA ; Michigan State U., NSCL) ; Ellis, John (CERN) ; Fields, Brian D. (Illinois U., Urbana) ; Luo, Feng (Minnesota U.) ; Olive, Keith A. (Minnesota U.) ; Spanos, Vassilis C. (Democritos Nucl. Res. Ctr.)
We consider the effects of uncertainties in nuclear reaction rates on the cosmological constraints on the decays of unstable particles during or after Big-Bang nucleosynthesis (BBN). We identify the nuclear reactions due to non-thermal hadrons that are the most important in perturbing standard BBN, then quantify the uncertainties in these reactions and in the resulting light-element abundances. [...]
arXiv:1007.4173; CERN-PH-TH-2010-163; UMN-TH-2911-10; FTPI-MINN-10-19; CERN-PH-TH-2010-163; UMN-TH-2911-10; FTPI-MINN-10-19.-
2010 - 24 p.
- Published in : JCAP 10 (2010) 032
Fulltext: PDF; External link: Preprint
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