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Title: Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified E{sub 6}

Abstract

The tensor-to-scalar ratio (r=0.20{sub −0.05}{sup +0.07}) inferred from the excess B-mode power observed by the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) experiment is almost twice as large as the 95% CL upper limits derived from temperature measurements of the WMAP (r<0.13) and Planck (r<0.11) space missions. Very recently, it was suggested that additional relativistic degrees of freedom beyond the three active neutrinos and photons can help to relieve this tension: the data favor an effective number of light neutrino species N{sub eff}=3.86±0.25. Since the BICEP2 ratio implies the energy scale of inflation (V{sub ∗}{sup 1/4}∼2×10{sup 16} GeV) is comparable to the grand unification scale, in this paper we investigate whether we can accommodate the required N{sub eff} with three right-handed (partners of the left-handed standard model) neutrinos living in the fundamental representation of a grand unified exceptional E{sub 6} group. We show that the superweak interactions of these Dirac states (through their coupling to a TeV-scale Z{sup ′} gauge boson) lead to decoupling of right-handed neutrino just above the QCD cross over transition: 175 MeV≲T{sub ν{sub R}{sup dec}}≲250 MeV. For decoupling in this transition region, the contribution of the three right-handed neutrinos to N{sub eff} is suppressed by heatingmore » of the left-handed neutrinos (and photons). Consistency (within 1σ) with the favored N{sub eff} is achieved for 4.5 TeV« less

Authors:
 [1];  [2];  [3];  [1]
  1. Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201 (United States)
  2. Department of Physics, Northeastern University, Boston, MA, 02115 (United States)
  3. Department of Physics, National Taiwan Normal University, Taipei, 116 Taiwan (China)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22454498
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2014)042; OAI: oai:repo.scoap3.org:2840; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COSMOLOGICAL INFLATION; DECOUPLING; DEGREES OF FREEDOM; GEV RANGE; MEV RANGE; MICROWAVE RADIATION; NEUTRINOS; PHOTONS; POLARIZATION; QUANTUM CHROMODYNAMICS; RELATIVISTIC RANGE; SCALARS; STANDARD MODEL; TEMPERATURE MEASUREMENT; TENSORS; TEV RANGE

Citation Formats

Anchordoqui, Luis A., Goldberg, Haim, Huang, Xing, and Vlcek, Brian J. Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified E{sub 6}. United States: N. p., 2014. Web. doi:10.1088/1475-7516/2014/06/042.
Anchordoqui, Luis A., Goldberg, Haim, Huang, Xing, & Vlcek, Brian J. Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified E{sub 6}. United States. doi:10.1088/1475-7516/2014/06/042.
Anchordoqui, Luis A., Goldberg, Haim, Huang, Xing, and Vlcek, Brian J. Tue . "Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified E{sub 6}". United States. doi:10.1088/1475-7516/2014/06/042.
@article{osti_22454498,
title = {Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified E{sub 6}},
author = {Anchordoqui, Luis A. and Goldberg, Haim and Huang, Xing and Vlcek, Brian J.},
abstractNote = {The tensor-to-scalar ratio (r=0.20{sub −0.05}{sup +0.07}) inferred from the excess B-mode power observed by the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) experiment is almost twice as large as the 95% CL upper limits derived from temperature measurements of the WMAP (r<0.13) and Planck (r<0.11) space missions. Very recently, it was suggested that additional relativistic degrees of freedom beyond the three active neutrinos and photons can help to relieve this tension: the data favor an effective number of light neutrino species N{sub eff}=3.86±0.25. Since the BICEP2 ratio implies the energy scale of inflation (V{sub ∗}{sup 1/4}∼2×10{sup 16} GeV) is comparable to the grand unification scale, in this paper we investigate whether we can accommodate the required N{sub eff} with three right-handed (partners of the left-handed standard model) neutrinos living in the fundamental representation of a grand unified exceptional E{sub 6} group. We show that the superweak interactions of these Dirac states (through their coupling to a TeV-scale Z{sup ′} gauge boson) lead to decoupling of right-handed neutrino just above the QCD cross over transition: 175 MeV≲T{sub ν{sub R}{sup dec}}≲250 MeV. For decoupling in this transition region, the contribution of the three right-handed neutrinos to N{sub eff} is suppressed by heating of the left-handed neutrinos (and photons). Consistency (within 1σ) with the favored N{sub eff} is achieved for 4.5 TeV},
doi = {10.1088/1475-7516/2014/06/042},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 06,
volume = 2014,
place = {United States},
year = {Tue Jun 17 00:00:00 EDT 2014},
month = {Tue Jun 17 00:00:00 EDT 2014}
}
  • The tensor-to-scalar ratio (r = 0.20{sup +0.07}{sub −0.05}) inferred from the excess B-mode power observed by the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) experiment is almost twice as large as the 95% CL upper limits derived from temperature measurements of the WMAP (r < 0.13) and Planck (r < 0.11) space missions. Very recently, it was suggested that additional relativistic degrees of freedom beyond the three active neutrinos and photons can help to relieve this tension: the data favor an effective number of light neutrino species N{sub eff} = 3.86±0.25. Since the BICEP2 ratio implies the energy scale ofmore » inflation (V{sub *}{sup 1/4} ∼ 2 × 10{sup 16} GeV) is comparable to the grand unification scale, in this paper we investigate whether we can accommodate the required N{sub eff} with three right-handed (partners of the left-handed standard model) neutrinos living in the fundamental representation of a grand unified exceptional E{sub 6} group. We show that the superweak interactions of these Dirac states (through their coupling to a TeV-scale Z' gauge boson) lead to decoupling of right-handed neutrino just above the QCD cross over transition: 175 MeV∼« less
  • We generalize the embedding of induced-gravity inflation beyond the no-scale Supergravity presented in ref. [1] employing two gauge singlet chiral superfields, a superpotential uniquely determined by applying a continuous R and a discrete Z{sub n} symmetries, and a logarithmic Kähler potential including all the allowed terms up to fourth order in powers of the various fields. We show that, increasing slightly the prefactor (-3) encountered in the adopted Kähler potential, an efficient enhancement of the resulting tensor-to-scalar ratio can be achieved rendering the predictions of the model consistent with the recent BICEP2 results, even with subplanckian excursions of the originalmore » inflaton field. The remaining inflationary observables can become compatible with the data by mildly tuning the coefficient involved in the fourth order term of the Kähler potential which mixes the inflaton with the accompanying non-inflaton field. The inflaton mass is predicted to be close to 10{sup 14} GeV.« less
  • We generalize the embedding of induced-gravity inflation beyond the no-scale Supergravity presented in ref. http://dx.doi.org/10.1088/1475-7516/2014/08/057 employing two gauge singlet chiral superfields, a superpotential uniquely determined by applying a continuous R and a discrete ℤ{sub n} symmetries, and a logarithmic Kähler potential including all the allowed terms up to fourth order in powers of the various fields. We show that, increasing slightly the prefactor (−3) encountered in the adopted Kähler potential, an efficient enhancement of the resulting tensor-to-scalar ratio can be achieved rendering the predictions of the model consistent with the recent BICEP2 results, even with subplanckian excursions of the originalmore » inflaton field. The remaining inflationary observables can become compatible with the data by mildly tuning the coefficient involved in the fourth order term of the Kähler potential which mixes the inflaton with the accompanying non-inflaton field. The inflaton mass is predicted to be close to 10{sup 14} GeV.« less
  • The degenerate leptogenesis is studied when the degeneracy in two of the heavy right-handed neutrinos [the third one is irrelevant if {mu}-{tau} symmetry is assumed] is due to L{identical_to}(L{sub e}-L{sub {mu}-}L{sub {tau}}) discrete symmetry. It is shown that a sizable leptogenesis asymmetry ({epsilon}{>=}10{sup -6}) is possible. The level of degeneracy required also predicts the Majorana phase needed for the asymmetry and this prediction is testable since it is the same phase, which appears in the double {beta} decay. Implications of nonzero reactor angle {theta}{sub 13} are discussed. It is shown that the contribution from sin{sup 2{theta}}{sub 13} to the leptogenesismore » asymmetry parameter may even dominate. An accurate measurement of sin{sup 2{theta}}{sub 13} would have important implications for the mass degeneracy of heavy right-handed neutrinos.« less