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Title: Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models

Abstract

In this talk we present a mechanism for leptogenesis which is based on gravity waves produced during inflation. We show that when inflation is driven by a pseudo-scalar field the metric perturbations generated during inflation can become birefringent, therefore giving a non-vanishing contribution to the gravitational triangle anomaly and sourcing lepton anti-lepton asymmetry. As this asymmetry is sourced by the fields which are active during inflation, it is not washed out or diluted by inflation. The amount of matter asymmetry generated in our model can be of realistic size for the parameters within the range of some inflationary scenarios and grand unified theories.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
900238
Report Number(s):
SLAC-PUB-12371
hep-ph/0701139; TRN: US200711%%317
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: In the Proceedings of IPM School and Conference on Lepton and Hadron Physics (IPM-LHP06), Tehran, Iran, 15-20 May 2006
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; EDUCATIONAL FACILITIES; GRAVITY WAVES; HADRONS; LEPTONS; METRICS; PHYSICS; Phenomenology-HEP,HEPPH

Citation Formats

Alexander, S.H., /Penn State U., Peskin, Michael E., /SLAC, Sheikh-Jabbari, M.M., and /IPM, Tehran. Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models. United States: N. p., 2007. Web.
Alexander, S.H., /Penn State U., Peskin, Michael E., /SLAC, Sheikh-Jabbari, M.M., & /IPM, Tehran. Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models. United States.
Alexander, S.H., /Penn State U., Peskin, Michael E., /SLAC, Sheikh-Jabbari, M.M., and /IPM, Tehran. Wed . "Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models". United States. doi:. https://www.osti.gov/servlets/purl/900238.
@article{osti_900238,
title = {Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models},
author = {Alexander, S.H. and /Penn State U. and Peskin, Michael E. and /SLAC and Sheikh-Jabbari, M.M. and /IPM, Tehran},
abstractNote = {In this talk we present a mechanism for leptogenesis which is based on gravity waves produced during inflation. We show that when inflation is driven by a pseudo-scalar field the metric perturbations generated during inflation can become birefringent, therefore giving a non-vanishing contribution to the gravitational triangle anomaly and sourcing lepton anti-lepton asymmetry. As this asymmetry is sourced by the fields which are active during inflation, it is not washed out or diluted by inflation. The amount of matter asymmetry generated in our model can be of realistic size for the parameters within the range of some inflationary scenarios and grand unified theories.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 28 00:00:00 EST 2007},
month = {Wed Feb 28 00:00:00 EST 2007}
}

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  • We present a new mechanism for creating the observed cosmic matter-antimatter asymmetry which satisfies all three Sakharov conditions from one common thread, gravitational waves. We generate lepton number through the gravitational anomaly in the lepton number current. The source term comes from elliptically polarized gravity waves that are produced during inflation if the inflaton field contains a CP-odd component. The amount of matter asymmetry generated in our model can be of realistic size for the parameters within the range of some inflationary scenarios and grand unified theories.
  • The energy levels of the left- and the right-handed neutrinos are split in the background of gravitational waves generated during inflation, which, in presence of lepton-number-violating interactions, gives rise to a net lepton asymmetry at equilibrium. Lepton number violation is achieved by the same dimension five operator which gives rise to neutrino masses after electroweak symmetry breaking. A net baryon asymmetry of the same magnitude can be generated from this lepton asymmetry by electroweak sphaleron processes.
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  • We consider a loop-quantum gravity inspired modification of general relativity, where the Holst action is generalized by making the Barbero-Immirzi (BI) parameter a scalar field, whose value could be dynamically determined. The modified theory leads to a nonzero torsion tensor that corrects the field equations through quadratic first derivatives of the BI field. Such a correction is equivalent to general relativity in the presence of a scalar field with nontrivial kinetic energy. This stress energy of this field is automatically covariantly conserved by its own dynamical equations of motion, thus satisfying the strong equivalence principle. Every general relativistic solution remainsmore » a solution to the modified theory for any constant value of the BI field. For arbitrary time-varying BI fields, a study of cosmological solutions reduces the scalar-field stress energy to that of a pressureless perfect fluid in a comoving reference frame, forcing the scale-factor dynamics to be equivalent to those of a stiff equation of state. Upon ultraviolet completion, this model could provide a natural mechanism for k inflation, where the role of the inflaton is played by the BI field and inflation is driven by its nontrivial kinetic energy instead of a potential.« less