Bounds on the top-quark mass in N=1 supergravity models

Chiou-Lahanas, C.; Georgalas, B.C.; Papadopoulos, Costas G.

doi:10.1016/0370-2693(87)90455-2

Cited by 4 publications

(19 citation statements)

References 17 publications

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“…For the most part we will assume that WIMPs have been in full thermal equilibrium. Various cosmological models predict a non-standard early expansion history [22,23,24,25]. Here we analyze to what extent the relic density of WIMP Dark Matter can be used to constrain the Hubble parameter during the epoch of WIMP decoupling.…”

Section: Relic Abundance For Modified Expansion Ratementioning

confidence: 99%

“…Another example of a non-standard cosmology changing the WIMP relic density is a modified expansion rate of the universe. This might be induced by an anisotropic expansion [16], by a modification of general relativity [16,22], by additional contributions to the total energy density from quintessence [23], by branes in a warped geometry [24], or by a superstring dilaton [25].…”

Section: Introductionmentioning

confidence: 99%

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Constraints on the very early universe from thermal WIMP dark matter

2007

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We investigate the relic density n χ of non-relativistic long-lived or stable particles χ in non-standard cosmological scenarios. We calculate the relic abundance starting from arbitrary initial temperatures of the radiationdominated epoch, and derive the lower bound on the initial temperature T 0 ≥ m χ /23, assuming that thermally produced χ particles account for the dark matter energy density in the universe; this bound holds for all χ annihilation cross sections. We also investigate cosmological scenarios with modified expansion rate. Even in this case an approximate formula similar to the standard one is capable of predicting the final relic abundance correctly. Choosing the χ annihilation cross section such that the observed cold dark matter abundance is reproduced in standard cosmology, we constrain possible modifications of the expansion rate at T ∼ m χ /20, well before Big Bang Nucleosynthesis.

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Section: Relic Abundance For Modified Expansion Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Constraints on the very early universe from thermal WIMP dark matter

2007

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“…18. For massive particles of mass m i , as long as we are in the temperature regime m i > T > T today , the energy density can be written as ρ i = nm i and in order to account for the presence of the dilatonic dissipative term, the Boltzmann equation should be modified accordingly [12,17]:…”

Section: Supercritical String Cosmologymentioning

confidence: 99%

“…These quantities are calculated after solving the cosmological equations. For a particle species i of mass m i , the freeze out point x f = T f /m i is found to be [17] x…”

Section: Supercritical String Cosmologymentioning

confidence: 99%

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Non-Critical String Cosmologies

Lahanas

2007

Int. J. Mod. Phys. A

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Non-critical String Cosmologies are offered as an alternative to Standard Big Bang Cosmology. The new features encompassed within the dilaton dependent non-critical terms affect the dynamics of the Universeś evolution in an unconventional manner being in agreement with the cosmological data. Non-criticality is responsible for a late transition to acceleration at redshifts z=0.2. The role of the uncoupled rolling dilaton to relic abundance calculations is discussed. The uncoupled rolling dilaton dilutes the neutralino relic densities in supersymmetric theories by factors of ten, relaxing considerably the severe WMAP Dark Matter constraints, while at the same time leaves almost unaffected the baryon density in agreement with primordial Nucleosynthesis.

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Smoothly evolving supercritical-string dark energy relaxes supersymmetric-dark-matter constraints

2007

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We show that Supercritical-String-Cosmology (SSC) off-equilibrium and time-dependent-dilaton effects lead to a smoothly evolving dark energy for the last 10 billion years in concordance with all presently available astrophysical data. Such effects dilute by a factor O (10) the supersymmetric dark matter density (neutralinos), relaxing severe WMAP 1,3 constraints on the SUSY parameter space. Thus, LHC anticipated searches/discoveries may discriminate between conventional and Supercritical-String Cosmology.

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Bounds on the top-quark mass in N=1 supergravity models

Cited by 4 publications

References 17 publications

Constraints on the very early universe from thermal WIMP dark matter

Constraints on the very early universe from thermal WIMP dark matter

Non-Critical String Cosmologies

Smoothly evolving supercritical-string dark energy relaxes supersymmetric-dark-matter constraints

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