313 research outputs found
New inflation in supergravity after Planck and LHC
We revisit a single-field new inflation model based on a discrete R symmetry.
Interestingly, the inflaton dynamics naturally leads to a heavy gravitino of
mass m_3/2 = O(1-100) TeV, which is consistent with the standard-model like
Higgs boson of mass mh = 126 GeV. However, the predicted spectral index n_s =
0.94 is in tension with the Planck result, n_s = 0.9603+-0.073. We show that
the spectral index can be increased by allowing a small constant term in the
superpotential during inflation. The required size of the constant is close to
the largest allowed value for successful inflation, and it may be a result of a
pressure toward larger values in the landscape. Alternatively, such constant
term may arise in association with supersymmetry breaking required to cancel
the negative cosmological constant from the inflaton sector.Comment: 15 pages, 2 figure
A possible anthropic solution to the Strong CP problem
We point out that the long-standing strong CP problem may be resolved by an
anthropic argument. The key ideas are: (i) to allow explicit breaking(s) of the
Peccei-Quinn symmetry which reduces the strong CP problem to the cosmological
constant problem, and (ii) to conjecture that the probability distribution of
the vacuum energy has a mild pressure towards higher values. The cosmological
problems of the (s)axion with a large Peccei-Quinn scale are absent in our
mechanism, since the axion acquires a large mass from the explicit breaking.Comment: 22 pages, 2 figures.v2: references added.v3:a version to appear in
Progress of Theoretical Physic
Higgs Chaotic Inflation and the Primordial B-mode Polarization Discovered by BICEP2
We show that the standard model Higgs field can realize the quadratic chaotic
inflation, if the kinetic term is significantly modified at large field values.
This is a simple realization of the so-called running kinetic inflation. The
point is that the Higgs field respects an approximate shift symmetry at high
energy scale. The tensor-to-scalar ratio is predicted to be , which nicely explains the primordial B-mode polarization,
, recently discovered by the BICEP2 experiment. In
particular, allowing small modulations induced by the shift symmetry breaking,
the negative running spectral index can also be induced. The reheating
temperature is expected to be so high that successful thermal leptogenesis is
possible. The suppressed quartic coupling of the Higgs field at high energy
scales may be related to the Higgs chaotic inflation.Comment: 12 pages. v2: discussion improved, references added. v3: matches with
published versio
PeV-scale Supersymmetry from New Inflation
We show that heavy supersymmetric particles around O(100) TeV to O(1) PeV
naturally appear in new inflation in which the Higgs boson responsible for the
breaking of U(1)B-L plays the role of inflaton. Most important, the
supersymmetric breaking scale is bounded above by the inflationary dynamics, in
order to suppress the Coleman-Weinberg potential which would otherwise spoil
the slow-roll inflation. Our scenario has rich phenomenological and
cosmological implications: the Higgs boson mass at around 125 GeV can be easily
explained, non-thermal leptogenesis works automatically, the gravitino
production from inflaton decay is suppressed, the dark matter is either the
lightest neutralino or the QCD axion, and the upper bound on the inflation
scale for the modulus stabilization can be marginally satisfied.Comment: 34 pages, 8 figures. v2: references adde
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