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Baryogenesis via leptogenesis in presence of cosmic strings

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dc.contributor.author Sahu, N
dc.contributor.author Bhattacharjee, P
dc.contributor.author Yajnik, U. A
dc.date.accessioned 2008-09-04T11:37:18Z
dc.date.available 2008-09-04T11:37:18Z
dc.date.issued 2006-09
dc.identifier.citation Nuclear Physics B, Vol. 752, No. 1 - 2, pp. 280 - 296 en
dc.identifier.issn 0550-3213
dc.identifier.uri http://hdl.handle.net/2248/3361
dc.description.abstract We study the effect on leptogenesis due to B L cosmic strings of a U1 extension of the Standard Model. The disappearance of closed loops of B L cosmic strings can produce heavy right handed neutrinos, N's, whose CP-asymmetric decay in out-of-thermal equilibrium condition can give rise to a net lepton (L) asymmetry which is then converted, due to sphaleron transitions, to a baryon (B) asymmetry. This is studied by using the relevant Boltzmann equations and including the effects of both thermal and string generated non-thermal N's. We explore the parameter region spanned by the effective light neutrino mass parameter m, the mass M of the lightest of the heavy right-handed neutrinos (or equivalently the Yukawa coupling h) and the scale of B L symmetry breaking, η, and show that there exist ranges of values of these parameters, in particular with η>10 GeV and h≳0.01, for which the cosmic string generated non-thermal N's can give the dominant contribution to, and indeed produce, the observed baryon asymmetry of the universe when the purely thermal leptogenesis mechanism is not sufficient. We also discuss how, depending on the values of η, m and h, our results lead to upper bounds on sinδ, where δ is the CP-violating phase that determines the CP asymmetry in the decay of the heavy right handed neutrino responsible for generating the L-asymmetry. en
dc.language.iso en en
dc.publisher Elsevier en
dc.relation.uri http://dx.doi.org/10.1016/j.nuclphysb.2006.06.034 en
dc.subject Baryogenesis en
dc.subject leptogenesis en
dc.subject Cosmic Strings en
dc.title Baryogenesis via leptogenesis in presence of cosmic strings en
dc.type Article en

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