1,014 research outputs found
Effects of Cosmological Moduli Fields on Cosmic Microwave Background
We discuss effects of cosmological moduli fields on the cosmic microwave
background (CMB). If a modulus field \phi once dominates the universe, the CMB
we observe today is from the decay of \phi and its anisotropy is affected by
the primordial fluctuation in the amplitude of the modulus field. Consequently,
constraints on the inflaton potential from the CMB anisotropy can be relaxed.
In particular, the scale of the inflation may be significantly lowered. In
addition, with the cosmological moduli fields, correlated mixture of adiabatic
and isocurvature fluctuations may be generated, which results in enhanced CMB
angular power spectrum at higher multipoles relative to that of lower ones.
Such an enhancement can be an evidence of the cosmological moduli fields, and
may be observed in future satellite experiments.Comment: 11pages, 4 figures, numerical error correcte
Non-Gaussianity and Baryonic Isocurvature Fluctuations in the Curvaton Scenario
We discuss non-Gaussianity and baryonic isocurvature fluctuations in the
curvaton scenario, assuming that the baryon asymmetry of the universe
originates only from the decay products of the inflaton. When large
non-Gaussianity is realized in such a scenario, non-vanishing baryonic
isocurvature fluctuations can also be generated unless the baryogenesis occurs
after the decay of the curvaton. We calculate the non-linearity parameter f_NL
and the baryonic isocurvature fluctuations, taking account of the primordial
fluctuations of both the inflaton and the curvaton. We show that, although
current constraints on isocurvature fluctuations are severe, the non-linearity
parameter can be large as f_NL \sim O(10-100) without conflicting with the
constraints.Comment: 14 pages, 3 figures, published versio
Can MSSM Particle be the Inflaton?
We consider the possibility of using one of the -flat directions in the
minimal supersymmetric standard model (MSSM) as the inflaton. We show that the
flat direction consisting of (first generation) left- and right-handed
up-squarks as well as the up-type Higgs boson may play the role of the inflaton
if dominant part of the up-quark mass is radiatively generated from
supersymmetric loop diagrams. We also point out that, if the R-parity violating
Yukawa coupling is of , -odd -flat directions may be another
possible candidate of the inflaton. Such inflation models using -flat
directions in the MSSM are not only testable with collider experiments but also
advantageous to resolve the problem how the inflaton reheats the universe.Comment: 13 pages, 1 figure; an explanatory comment and references are adde
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