Related papers: Gravitino production in the Randall-Sundrum II bra…
We investigate the thermal production of gravitinos in the context of the brane world cosmology. Since the expansion law is modified from the one in the standard cosmology, the Boltzmann equation for the gravitino production is altered. We…
Gravitational particle production in time variable metric of an expanding universe is efficient only when the Hubble parameter $H$ is not too small in comparison with the particle mass. In standard cosmology, the huge value of the Planck…
In string theory, even when there are ten to the thousand power vacuum states, does inflation produce overwhelmingly one preferred type of vacuum state? We respond affirmatively to questions whether existence of graviton production is…
The evolution of the cosmological perturbations is studied in the context of the Randall-Sundrum brane world scenario, in which our universe is realized on a three-brane in the five dimensional Anti-de Sitter(AdS) spacetime. We develop a…
A scenario for gravitational particle creation in a stiff matter dominated flat Friedmann-Robertson-Walker universe is presented. The primary creation of scalar particles is calculated using quantum field theory in curved spacetime and it…
The gravitino may well play an important role in cosmology, not only because its interactions are Planck-suppressed and therefore long-lived, but also because it is copiously produced via various processes such as particle scatterings in…
Effects of the unstable gravitino on the big-bang nucleosynthesis (BBN) and its implications to particle cosmology are discussed. If the gravitino mass is smaller than \sim 20 TeV, lifetime of the gravitino becomes longer than \sim 1sec and…
If our Universe is a 3+1 brane in a warped 4+1 dimensional bulk so that its expansion can be understood as the motion of the brane in the bulk, the time dependence of the boundary conditions for arbitrary bulk fields can lead to particle…
Late-decaying particles naturally arise in many extensions of the Standard Model, directly impacting key cosmological processes in the early universe, such as Big Bang Nucleosynthesis (BBN). BBN studies often consider electromagnetic energy…
Cosmological issues of the gravitino production by the decay of a heavy scalar field $X$ are examined, assuming that the damped coherent oscillation of the scalar once dominates the energy of the universe. The coupling of the scalar field…
We derive the generalized Friedmann equation governing the cosmological evolution inside the thick brane model in the presence of two curvature correction terms: a four-dimensional scalar curvature from induced gravity on the brane, and a…
Modifications to the Friedmann equation in brane cosmology can have important implications for early universe phenomena such as inflation and the generation of the baryon asymmetry. We study a simple scenario of chaotic brane inflation…
In a general phenomenological model with local supersymmetry, the amount of massive gravitinos produced in early universe tends to violate the known dark matter density bound by many orders of magnitude. In the brane world scenario in Type…
If the observable universe is a braneworld of Randall-Sundrum type, then particle interactions at high energies will produce 5-dimensional gravitons that escape into the bulk. As a result, the Weyl energy density on the brane does not…
The cosmology of the Randall-Sundrum scenario for a positive tension brane in a 5-D Universe with localized gravity has been studied extensively recently. Here we extend it to more general situations. We consider the time-dependent…
The cosmology of the Randall-Sundrum scenario for a positive tension brane in a 5-D Universe with localized gravity has been studied previously. In the radiation-dominated Universe, it was suggested that there are two solutions for the…
In a model of 3-brane embedded in 5D space-time we calculate the graviton emission from the brane to the bulk. Matter is confined to the brane, gravitons produced in reactions of matter on the brane escape to the bulk. The Einstein…
The Friedmann equations for a brane with induced gravity are analyzed and compared with the standard general relativity and Randall-Sundrum cases. Randall-Sundrum gravity modified the early universe dynamics, whereas induced gravity changes…
We study a class of braneworlds where the cosmological evolution arises as the result of the movement of a three-brane in a five-dimensional static dilatonic bulk, with and without reflection symmetry. The resulting four-dimensional…
We derive big-bang nucleosynthesis (BBN) constraints on both unstable and stable gravitino taking account of recent progresses in theoretical study of the BBN processes as well as observations of primordial light-element abundances. In the…