Smooth hybrid inflation in supergravity with a running spectral index and early star formation

Yamaguchi, Masahide; Yokoyama, Jun′ichi

doi:10.1103/physrevd.70.023513

Cited by 43 publications

(27 citation statements)

References 37 publications

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“…If confirmed, a nonvanishing running of α s would not only constrain inflationary cosmology significantly [16,17,18,19,20,21], but also affect the cosmological constraint on the neutrino mass. In the LSS power spectrum, the effect of massive neutrino may be compensated by a nonvanishing running of primordial spectrum.…”

Section: Pacs Number(s): 9880cqmentioning

confidence: 99%

“…Moreover, a nontrivial negative running of the scalar spectral index α s , whose existence was studied even before WMAP epoch [10,11], was favored by the first-year WMAP papers [12,13,14]. But its preference was somehow diminished as corrections to the likelihood functions were made [15].However, the new WMAP3 data prefers again a negative running in the "All" combination [5].If confirmed, a nonvanishing running of α s would not only constrain inflationary cosmology significantly [16,17,18,19,20,21], but also affect the cosmological constraint on the neutrino mass. In the LSS power spectrum, the effect of massive neutrino may be compensated by a nonvanishing running of primordial spectrum.…”

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confidence: 99%

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Weighing neutrinos in the presence of a running primordial spectral index

Feng

Xia

Yokoyama

et al. 2006

J. Cosmol. Astropart. Phys.

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The three-year WMAP(WMAP3), combined with other cosmological observations from galaxy clustering and Type Ia Supernova (SNIa), prefers a non-vanishing running of the primordial spectral index independent of the low CMB multipoles. Motivated by this feature we study cosmological constraint on the neutrino mass, which severely depends on what prior we adopt for the spectral shape of primordial fluctuations, taking possible running into account. As a result we find a more stringent constraint on the sum of the three neutrino masses, mν < 0.76eV (2 σ), compared with mν < 0.90eV (2 σ) for the case where power-law prior is adopted to the primordial spectral shape. PACS number(s): 98.80.CqThe three year Wilkinson Microwave Anisotropy Probe observations (WMAP3) [1,2,3,4, 5] have marked another milestone on the precision cosmology of the Cosmic Microwave Background (CMB) Radiation. The simplest six-parameter power-law ΛCDM cosmology is in remarkable agreement with WMAP3 together with the large scale structure(LSS) of galaxy clustering as measured by 2dF [6] and SDSS [7] and with the Type Ia Supernova (SNIa) as measured by the Riess "gold" sample [8] and the first year SNLS [9]. This agreement between the above "canonical" cosmological model and observations can be used to test a number of possible new physics, such as the equation of state of dark energy, neutrino masses, time variation of fundamental constants, etc.Among them, the constraint on the neutrino or hot dark matter mass can be obtained from the freestreaming modification of the transfer function of the matter power spectrum. We should note, however, that if one allowed any shape of primordial spectrum, the freestreaming effect could easily be compensated by some nontrivial shape of the primordial spectrum, so that one cannot obtain sensible limit on the neutrino mass. That is, we can obtain a nontrivial bound on neutrino mass if and only if we adopt some prior on the shape of primordial power spectrum such as a simple power-law. From the above argument, we expect that as we allow more degrees of freedom on the primordial spectrum beyond a power-law, the constraint on the neutrino mass would be less stringent in general.As for the shape of the primordial power spectrum, it is noteworthy that a significant deviation has been observed by WMAP3 from the simplest Harrison-Zel'dovich spectrum, and that this feature is more eminent with the combination of all the currently available CMB, LSS and SNIa (dubbed the case of "All" in [5]). Moreover, a nontrivial negative running of the scalar spectral index α s , whose existence was studied even before WMAP epoch [10,11], was favored by the first-year WMAP papers [12,13,14]. But its preference was somehow diminished as corrections to the likelihood functions were made [15].However, the new WMAP3 data prefers again a negative running in the "All" combination [5].If confirmed, a nonvanishing running of α s would not only constrain inflationary cosmology significantly [16,17,18,19,20,21], but also affect the cosmological c...

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Section: Pacs Number(s): 9880cqmentioning

confidence: 99%

mentioning

confidence: 99%

Weighing neutrinos in the presence of a running primordial spectral index

Feng

Xia

Yokoyama

et al. 2006

J. Cosmol. Astropart. Phys.

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“…The initial conditions for inflation (φ ≈ 0) can be generated dynamically by a stage of preinflation [21][22][23]34]. If χ is non-zero, a χ dependent mass is generated for φ which stabilizes the inflaton near the hilltop (φ = 0).…”

Section: Initial Conditions and Preinflationmentioning

confidence: 99%

Parametric resonance after hilltop inflation caused by an inhomogeneous inflaton field

Antusch

Cefalà

Nolde

et al. 2016

J. Cosmol. Astropart. Phys.

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We study preheating after hilltop inflation where the inflaton couples to another scalar field, e.g. a right-handed sneutrino, which provides a mechanism for generating the correct initial conditions for inflation and also a decay channel for the inflaton that allows for reheating and non-thermal leptogenesis. In the presence of such a coupling, we find that after the phases of tachyonic preheating and tachyonic oscillations, during which the inflaton field becomes inhomogeneous, there can be a subsequent preheating phase where the fluctuations of the other field get resonantly enhanced, from initial vacuum fluctuations up to amplitudes of the same order (and even larger) as the ones of the inflaton field. This resonant enhancement differs from the usual parametric resonance as the inflaton field is inhomogeneous at the time the enhancement takes place. We study this effect using lattice simulations as well as semi-analytically with a generalized Floquet analysis for inhomogeneous background fields. 1

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“…In a typical supersymmetric hybrid inflation framework based on a given GUT gauge group, G, we usually consider a gauge singlet superfield, S, along with a gauge non-singlet conjugate pair of Higgs superfields H and H. Some of the examples of the GUT gauge groups are SO(10), SU(5) × U(1) and SU(4) c × SU(2) L × SU(2) R with Higgs superfields residing in the 16, 10 and (4, 1, 2) dimensional representations of the respective gauge groups [14]. With this minimal content of superfields and the U(1) R ×Z n global symmetry we obtain the following simple form of the superpotential [15,16],…”

Section: Introductionmentioning

confidence: 99%

“…Once the field S is stabilized we obtain an effective Higgs potential which, for values of fields below M, can be used for new inflation. For example, see [15] where it is used to realize pre-inflation in order to justify the initial conditions of new inflation. In ref.…”

Section: Introductionmentioning

confidence: 99%

Nonminimal inflation in supersymmetric GUTs with U(1)R × Zn symmetry

Masoud

Rehman

Abid

2019

Int. J. Mod. Phys. D

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A supersymmetric hybrid inflation framework is employed to realize a class of non-minimal inflation models with U (1) R × Z n global symmetry. This framework naturally incorporates models based on grand unified theories by avoiding the most commonly faced monopole problem. The predictions of inflationary observables, the scalar spectral index n s = 0.960 − 0.966 and the tensor to scalar ratio r = 0.0031 − 0.0045, are in perfect agreement with the Planck 2018 data. For sub-Planckian values of the field the Z n symmetry is only allowed for n ≤ 4.

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Smooth hybrid inflation in supergravity with a running spectral index and early star formation

Cited by 43 publications

References 37 publications

Weighing neutrinos in the presence of a running primordial spectral index

Weighing neutrinos in the presence of a running primordial spectral index

Parametric resonance after hilltop inflation caused by an inhomogeneous inflaton field

Nonminimal inflation in supersymmetric GUTs with U(1)R × Zn symmetry

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