50 research outputs found
Neutralino and gravitino dark matter with low reheating temperature
We examine a scenario in which the reheating temperature 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 , 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 scenario. We show
that the prospects for bino detection strongly depend on , 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 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 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
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
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
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
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
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
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