Dark matter in a constrained E 6 inspired SUSY model (original) (raw)
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New constraints on neutralino dark matter in the supersymmetric standard model
Physical Review D, 1993
We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance Omegachih20\Omega_\chi h^2_0Omegachih20 depends most strongly on the ratio xi0equivm0/m1/2\xi_0\equiv m_0/m_{1/2}xi0equivm0/m1/2. For xi0gg1\xi_0\gg1xi0gg1 the relic abundance is almost always much too large, whereas for xi0ll1\xi_0\ll1xi0ll1 the opposite occurs. For xi0sim1\xi_0\sim1xi0sim1 there are wide ranges of the remaining parameters for which Omegachisim1\Omega_\chi\sim1Omegachisim1. We also determine that mtildeqgsim250GeVm_{\tilde q}\gsim250\GeVmtildeqgsim250GeV and mtildelgsim100GeVm_{\tilde l}\gsim100\GeVmtildelgsim100GeV are necessary in order to possibly achieve Omegachisim1\Omega_\chi\sim1Omegachisim1. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.
Physics of Atomic Nuclei, 2002
Direct detection experiments for neutralino dark matter in the Milky Way are examined within the framework of SUGRA models with R-parity invariance and grand unification at the GUT scale, M G. Models of this type apply to a large number of phenomena, and all existing bounds on the SUSY parameter space due to current experimental constraints are included. For models with universal soft breaking at M G (mSUGRA), the Higgs mass and b → sγ constraints imply that the gaugino mass, m 1/2 , obeys m 1/2 >(300-400)GeV putting most of the parameter space in the co-annihilation domain where there is a relatively narrow band in the m 0 − m 1/2 plane. For µ > 0 we find that the neutralino-proton cross section > ∼ 10 −10 pb for m 1/2 < 1 TeV, making almost all of this parameter space accessible to future planned detectors. For µ < 0, however, there will be large regions of parameter space with cross sections < 10 −12 pb, and hence unaccessible experimentally. If, however, the muon magnetic moment anomaly is confirmed, then µ > 0 and m 1/2 < ∼ 800 GeV. Models with non-universal soft breaking in the third generation and Higgs sector can allow for new effects arising from additional early universe annihilation through the Z-channel pole. Here cross sections that will be accessible in the near future to the next generation of detectors can arise, and can even rise to the large values implied by the DAMA data. Thus dark matter detectors have the possibility of studying the the post-GUT physics that control the patterns of soft breaking.
Light neutralino dark matter in the next-to-minimal supersymmetric standard model
Physical Review D, 2006
Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need to be the case, however. In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and other supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs boson can naturally arise making it possible for a very light neutralino to annihilate efficiently enough to avoid being overproduced in the early Universe. In this article, we explore the characteristics of a supersymmetric model needed to include a very light neutralino, 100 MeV < m χ 0 1 < 20 GeV, using the NMSSM as a prototype. We discuss the most important constraints from Upsilon decays, b → sγ, B s → µ + µ − and the magnetic moment of the muon, and find that a light bino or singlino neutralino is allowed, and can be generated with the appropriate relic density. It has previously been shown that the positive detection of dark matter claimed by the DAMA collaboration can be reconciled with other direct dark matter experiments such as CDMS II if the dark matter particle is rather light, between about 6 and 9 GeV. A singlino or bino-like neutralino could easily fall within this range of masses within the NMSSM. Additionally, models with sub-GeV neutralinos may be capable of generating the 511 keV gamma-ray emission observed from the galactic bulge by the INTEGRAL/SPI experiment. We also point out measurements which can be performed immediately at CLEO, BaBar and Belle using existing data to discover or significantly constrain this scenario.
SUSY interpretation of the Egret GeV anomaly, Xenon-10 dark matter search limits and the LHC
The observation of the Egret experiment of an excess of diffuse gamma rays with energies above E γ = 1 GeV has previously been interpreted in the context of the minimal supergravity model (mSUGRA) as coming from neutralino annihilation into mainly bquarks in the galactic halo, with neutralino mass in the vicinity of 50-70 GeV. We observe that in order to obtain the correct relic abundance of neutralinos in accord with WMAP measurements, the corresponding neutralino-proton direct detection (DD) rates should be in excess of recent limits from the Xenon-10 collaboration. While it does not appear possible to satisfy the Egret, WMAP and Xenon-10 constraints simultaneously within the mSUGRA model, we find that it is easily possible in models with non-universal Higgs soft masses (NUHM). In either case, gluino pair production from mg ∼ 400 − 500 GeV should occur at large rates at the CERN LHC, and a gluino pair production signal should be visible with just 0.1 fb −1 of integrated luminosity. The NUHM interpretation predicts a rather light spectrum of heavy Higgs bosons with m A ∼ 140 − 200 GeV over the whole parameter space which would interpret Egret data. Spin-independent DD rates are predicted to be just above 10 −8 pb, within range of the next round of direct dark matter detection experiments.
Physical Review D, 2006
We explore the prospects for indirect detection of neutralino dark matter in supersymmetric models with an extended Higgs sector (NMSSM). We compute, for the first time, one-loop amplitudes for NMSSM neutralino pair annihilation into two photons and two gluons, and point out that extra diagrams (with respect to the MSSM), featuring a potentially light CP-odd Higgs boson exchange, can strongly enhance these radiative modes. Expected signals in neutrino telescopes due to the annihilation of relic neutralinos in the Sun and in the Earth are evaluated, as well as the prospects of detection of a neutralino annihilation signal in space-based gamma-ray, antiproton and positron search experiments, and at low-energy antideuteron searches. We find that in the low mass regime the signals from capture in the Earth are enhanced compared to the MSSM, and that NMSSM neutralinos have a remote possibility of affecting solar dynamics. Also, antimatter experiments are an excellent probe of galactic NMSSM dark matter. We also find enhanced two photon decay modes that make the possibility of the detection of a monochromatic gamma-ray line within the NMSSM more promising than in the MSSM. I. INTRODUCTION Numerous theoretical and phenomenological motivations exist for a Minimal Supersymmetric extension of the Standard Model (MSSM). At the same time one of the attractive by-products of low energy supersymmetry is the natural occurrence in the particle content of the theory of a stable weakly interacting massive particle, the lightest neutralino, which could be the microscopic constituent of the as yet unobserved galactic halo dark matter. Another strong motivation comes from the SM hierarchy problem, originating from the large fine-tuning required by the stability of the electroweak scale to radiative corrections, originating from the large number of orders of magnitude occurring between the GUT, or the Planck, scale, and the electroweak scale itself. Although very appealing, the MSSM has been challenged by various pieces of experimental information, and by some arguments of more theoretical nature. Among these, the LEP-II limit on the mass of the lightest CP-even Higgs [1], the constraints on the masses of supersymmetric (Susy) charged or colored particles from direct searches at LEP and at the Tevatron [2], and the so-called µ problem, i.e. the fundamental reason why the Susy Higgsino mass term µ appearing in the MSSM superpotential lies at some scale near the electroweak scale rather than at some much higher scale. The addition of a new gauge singlet chiral multiplet,Ŝ, to the particle content of the MSSM can provide an elegant solution to the mentioned µ problem of the MSSM [3]. The so-called Next to Minimal Supersymmetric Standard Model (NMSSM) [4] is an example of one such minimal extension that also alleviates the little fine tuning problem of the MSSM, arising from the non-detection of a neutral CP-even Higgs at LEP-II [1]. A further motivation to go beyond the MSSM comes from Electro-Weak Baryogenesis (EWB), i.e. the possibility that the baryon asymmetry of the Universe originated through electro-weak physics at the electro-weak phasetransition in the Early Universe. Although still a viable scenario within the MSSM [5], EWB generically requires the Higgs mass to be in the narrow mass range above the current LEP-II limits and below ≃ 120 GeV, a rather unnatural mass splitting between the right-handed and the left-handed stops (the first one required to lie below the top quark mass, and the other in the multi-TeV range), CP violation at levels sometimes at odds with electric dipole moment experimental results, and, generically, a very heavy sfermion sector [6]. In contrast, the NMSSM provides extra triscalar Higgs couplings which hugely facilitate the occurrence of a more strongly first-order EW phase transition, and extra CP violating sources, relaxing most of the above mentioned requirements in the context of the MSSM [7, 8]. One of the chief remaining cosmological issues associated with the NMSSM, the cosmological domain wall problem [9], caused by the discrete Z 3 symmetry of the NMSSM, can be circumvented by introducing non-renormalizable Planck-suppressed operators [10]. The Higgs sector of the NMSSM contains three CP-even and two CP-odd scalars, which are mixtures of MSSM-like Higgses and singlets. Also, the neutralino sector contains five mass-eigenstates, instead of the four in the MSSM, each of which has, in addition to the four MSSM components, a singlino component, the latter being the fermionic partner of the extra singlet scalars. The extended Higgs and neutralino sectors weaken the mass bounds for both the Higgs bosons and the neutralinos. Very light neutralinos and Higgs bosons, even in the few GeV range, are in fact not
2019
The observation of the Egret experiment of an excess of diffuse gamma rays with energies above Eγ = 1 GeV has previously been interpreted in the context of the minimal supergravity model (mSUGRA) as coming from neutralino annihilation into mainly bquarks in the galactic halo, with neutralino mass in the vicinity of 50-70 GeV. We observe that in order to obtain the correct relic abundance of neutralinos in accord with WMAP measurements, the corresponding neutralino-proton direct detection (DD) rates should be in excess of recent limits from the Xenon-10 collaboration. While it does not appear possible to satisfy the Egret, WMAP and Xenon-10 constraints simultaneously within the mSUGRA model, we find that it is easily possible in models with non-universal Higgs soft masses (NUHM). In either case, gluino pair production from mg̃ ∼ 400− 500 GeV should occur at large rates at the CERN LHC, and a gluino pair production signal should be visible with just 0.1 fb of integrated luminosity. Th...
Phys Rev D, 2011
We analyze supergravity models that predict a low mass gluino within the landscape of sparticle mass hierarchies. The analysis includes a broad class of models that arise in minimal and in nonminimal supergravity unified frameworks and in extended models with additional U(1)Xn hidden sector gauge symmetries. Gluino masses in the range (350-700) GeV are investigated. Masses in this range are promising for early discovery at the LHC at s=7TeV (LHC-7). The models exhibit a wide dispersion in the gaugino-Higgsino eigencontent of their lightest supersymmetric particles and in their associated sparticle mass spectra. A signature analysis is carried out and the prominent discovery channels for the models are identified with most models needing only ˜1fb-1 for discovery at LHC-7. In addition, significant variations in the discovery capability of the low mass gluino models are observed for models in which the gluino masses are of comparable size due to the mass splittings in different models and the relative position of the light gluino within the various sparticle mass hierarchies. The models are consistent with the current stringent bounds from the Fermi-LAT, CDMS-II, XENON100, and EDELWEISS-2 experiments. A subclass of these models, which include a mixed-w-ino lightest supersymmetric particle and a Higgsino lightest supersymmetric particle, are also shown to accommodate the positron excess seen in the PAMELA satellite experiment.
Supersymmetric Dark Matter and Recent Experimental Constraints
Dark Matter in Astro- and Particle Physics, 2002
In this talk we discuss the impact of recent experimental information, like the revised bound from E821 Brookhaven experiment on gµ − 2 and light Higgs boson mass bound from LEP, in delineating regions of the parameters of the Constrained Minimal Supersymmetric Standard Model which are consistent with the cosmological data. The effect of these to Dark Matter direct searches is also discussed.
LHC constraints on light neutralino dark matter in the MSSM
Physics Letters B, 2013
Light neutralino dark matter can be achieved in the Minimal Supersymmetric Standard Model if staus are rather light, with mass around 100 GeV. We perform a detailed analysis of the relevant supersymmetric parameter space, including also the possibility of light selectons and smuons, and of light higgsino-or wino-like charginos. In addition to the latest limits from direct and indirect detection of dark matter, ATLAS and CMS constraints on electroweak-inos and on sleptons are taken into account using a "simplified models" framework. Measurements of the properties of the Higgs boson at 125 GeV, which constrain amongst others the invisible decay of the Higgs boson into a pair of neutralinos, are also implemented in the analysis. We show that viable neutralino dark matter can be achieved for masses as low as 15 GeV. In this case, light charginos close to the LEP bound are required in addition to light right-chiral staus. Significant deviations are observed in the couplings of the 125 GeV Higgs boson. These constitute a promising way to probe the light neutralino dark matter scenario in the next run of the LHC. *
Physical Review D, 2008
The observation of the Egret experiment of an excess of diffuse gamma rays with energies above E γ = 1 GeV has previously been interpreted in the context of the minimal supergravity model (mSUGRA) as coming from neutralino annihilation into mainly bquarks in the galactic halo, with neutralino mass in the vicinity of 50-70 GeV. We observe that in order to obtain the correct relic abundance of neutralinos in accord with WMAP measurements, the corresponding neutralino-proton direct detection (DD) rates should be in excess of recent limits from the Xenon-10 collaboration. While it does not appear possible to satisfy the Egret, WMAP and Xenon-10 constraints simultaneously within the mSUGRA model, we find that it is easily possible in models with non-universal Higgs soft masses (NUHM). In either case, gluino pair production from mg ∼ 400 − 500 GeV should occur at large rates at the CERN LHC, and a gluino pair production signal should be visible with just 0.1 fb −1 of integrated luminosity. The NUHM interpretation predicts a rather light spectrum of heavy Higgs bosons with m A ∼ 140 − 200 GeV over the whole parameter space which would interpret Egret data. Spin-independent DD rates are predicted to be just above 10 −8 pb, within range of the next round of direct dark matter detection experiments.