50 research outputs found

    Neutralino and gravitino dark matter with low reheating temperature

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    We examine a scenario in which the reheating temperature TRT_R after inflation is so low that it is comparable to, or lower than, the freeze out temperature of ordinary WIMPs. In this case the dark matter relic abundance is reduced, thus relaxing the impact of the usually strong constraint coming from the requirement that the universe does not overclose. We first re-examine the dynamics of freezeout during reheating. Next we apply a Bayesian approach to study the parameter space of the MSSM with ten free parameters, the CMSSM and the singlino-dominated regions of the NMSSM. In each case we find dramatic departures from the usually considered regime of high TRT_R, with important implications for direct detection dark matter searches. In the MSSM we examine WIMP mass range up to ~5 TeV, and find regions of bino dark matter over the whole mass range, and of higgsino dark matter with mass over a similar range but starting from the ~1 TeV value of the standard high TRT_R scenario. We show that the prospects for bino detection strongly depend on TRT_R, while the higgsino is for the most part detectable by future one-tonne detectors. The wino, which is excluded in the standard scenario, becomes allowed again if its mass is roughly above 3.5 TeV, and can be detectable. In the CMSSM, the bino and higgsino mass ranges become more constrained although detection prospects remain similar. In the Next-to-MSSM at low enough TRT_R wide ranges of singlino-dominated parameter space of the model become cosmologically allowed. We also study the contribution to the DM relic density from direct and cascade decays of the inflaton. Finally, we consider the case of a gravitino as dark matter. We find strong bounds from overclosure and Big Bang Nucleosynthesis, and derive lower limits on TRT_R which depend on the gravitino mass and on the nature of the lightest ordinary superpartner.Comment: section and references adde

    Axino dark matter with low reheating temperature

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    We examine axino dark matter in the regime of a low reheating temperature T_R after inflation and taking into account that reheating is a non-instantaneous process. This can have a significant effect on the dark matter abundance, mainly due to entropy production in inflaton decays. We study both thermal and non-thermal production of axinos in the context of the MSSM with ten free parameters. We identify the ranges of the axino mass and the reheating temperature allowed by the LHC and other particle physics data in different models of axino interactions. We confront these limits with cosmological constraints coming the observed dark matter density, large structures formation and big bang nucleosynthesis. We find a number of differences in the phenomenologically acceptable values of the axino mass and the reheating temperature relative to previous studies. In particular, an upper bound on the axino mass becomes dependent on T_R, reaching a maximum value at T_R~10^2 GeV. If the lightest ordinary supersymmetric particle is a wino or a higgsino, we obtain lower a limit of approximately 10 GeV for the reheating temperature. We demonstrate also that entropy production during reheating affects the maximum allowed axino mass and lowest values of the reheating temperature.Comment: v2: improved discussion of warm dark matter bounds, results for stau LOSP adde

    Gravitino dark matter with constraints from Higgs boson mass and sneutrino decays

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    We investigate gravitino dark matter produced thermally at high temperatures and in decays of a long-lived sneutrino. We consider the Non-Universal Higgs Model and a generalized gauge mediation model, and in each case identify sneutrino LOSP regions of the parameter space consistent with the mass of the Higgs-like boson observed at the LHC. We apply relevant collider and cosmological bounds, including constraints from Big Bang Nucleosynthesis and from warm dark matter on large scale structures. Generally, we find allowed values of the reheating temperature TR below 10^9 GeV, i.e. somewhat smaller than the values needed for thermal leptogenesis, even with a conservative lower bound of 122 GeV on the Higgs mass. Requiring mass values closer to 126 GeV implies TR below 10^7 GeV and the gravitino mass less than 10 GeV.Comment: 19 pages, 19 figures, version published in JHE

    Extending the reach of FASER, MATHUSLA, and SHiP towards smaller lifetimes using secondary particle production

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    Many existing or proposed intensity-frontier search experiments look for decay signatures of light long-lived particles (LLPs), highly displaced from the interaction point, in a distant detector that is well-shielded from SM background. This approach is, however, limited to new particles with decay lengths similar to or larger than the baseline of those experiments. In this study, we discuss how this basic constraint can be overcome in BSM models that go beyond the simplest scenarios. If more than one light new particle is present in the model, an additional secondary production of LLPs may take place right in front of the detector, opening this way a new lifetime regime to be probed. We illustrate the prospects of such searches in the future experiments FASER, MATHUSLA and SHiP, for representative models, emphasizing possible connections to dark matter or an anomalous magnetic moment of muon. We also analyze additional advantages from employing dedicated neutrino detectors placed in front of the main decay volume.Comment: 33 pages, 13 figures, 1 table, typos corrected in appendices, no results affecte

    Analiza odporności inwestycji w nieruchomości biurowe na wzrost kosztów kredyt lub stopy pustostanów

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    This paper presents the analysis of the robustness of office investment when the credit costs or the vaccancy rate increases. The analysis is performed on the average data that was obtained from 10 class B office buildings which are located in Warsaw. The data was collected by the Narodowy Bank Polski

    Analiza odporności inwestycji w nieruchomości biurowe na wzrost kosztów kredyt lub stopy pustostanów

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    This paper presents the analysis of the robustness of office investment when the credit costs or the vaccancy rate increases. The analysis is performed on the average data that was obtained from 10 class B office buildings which are located in Warsaw. The data was collected by the Narodowy Bank Polski

    Self-Adaptive Differential Evolution with Hybrid Rules of Perturbation for Dynamic Optimization, Journal of Telecommunications and Information Technology, 2011, nr 4

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    In this paper an adaptive differential evolution approach for dynamic optimization problems is studied. A new benchmark suite Syringa is also presented. The suite allows to generate test-cases from a multiple number of dynamic optimization classes. Two dynamic benchmarks: Generalized Dynamic Benchmark Generator (GDBG) and Moving Peaks Benchmark (MPB) have been simulated in Syringa and in the presented research they were subject of the experimental research. Two versions of adaptive differential evolution approach, namely the jDE algorithm have been heavily tested: the pure version of jDE and jDE equipped with solutions mutated with a new operator. The operator uses a symmetric a-stable distribution variate for modification of the solution coordinates
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