Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitinos from Heavy Scalar Decay   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 to a gravitino pair is estimated both in spontaneous and explicit
supersymmetry breaking scenarios, with the result that it is proportional to
the vacuum expectation value of the scalar field in general. Cosmological
constraints depend on whether the gravitino is stable or not, and we study each
case separately. For the unstable gravitino with $M_{3/2} \sim$ 100GeV--10TeV,
we obtain not only the upper bound, but also the lower bound on the reheating
temperature after the $X$ decay, in order to retain the success of the big-bang
nucleosynthesis. It is also shown that it severely constrains the decay rate
into the gravitino pair. For the stable gravitino, similar but less stringent
bounds are obtained to escape the overclosure by the gravitinos produced at the
$X$ decay. The requirement that the free-streaming effect of such gravitinos
should not suppress the cosmic structures at small scales eliminates some
regions in the parameter space, but still leaves a new window of the gravitino
warm dark matter. Implications of these results to inflation models are
discussed. In particular, it is shown that modular inflation will face serious
cosmological difficulty when the gravitino is unstable, whereas it can escape
the constraints for the stable gravitino. A similar argument offers a solution
to the cosmological moduli problem, in which the moduli is relatively heavy
while the gravitino is light.

11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio