dc.contributor.author |
Bhattacharjee, P |
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dc.contributor.author |
Sahu, N |
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dc.contributor.author |
Yajnik, U.A |
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dc.date.accessioned |
2008-06-04T11:25:38Z |
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dc.date.available |
2008-06-04T11:25:38Z |
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dc.date.issued |
2004-10 |
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dc.identifier.citation |
Physical Review D, Vol. 70, pp. 083534 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/2399 |
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dc.description.abstract |
Cosmic strings arising from breaking of the $U(1)_{B-L}$ gauge symmetry that occurs in a wide variety of unified models can carry zero modes of heavy Majorana neutrinos. Decaying and/or repeatedly self-interacting closed loops of these ``$B-L$'' cosmic strings can be a non-thermal source of heavy right-handed Majorana neutrinos whose decay can contribute to the observed baryon asymmetry of the Universe (BAU) via the leptogenesis route. The $B-L$ cosmic strings are expected in GUT models such as SO(10), where they can be formed at an intermediate stage of symmetry breaking well below the GUT scale $\sim 10^{16}$ GeV; such light strings are not excluded by the CMB anisotropy data and may well exist. We estimate the contribution of $B-L$ cosmic string loops to the baryon-to-photon ratio of the Universe in the light of current knowledge on neutrino masses and mixings implied by atmospheric and solar neutrino measurements. We find that $B-L$ cosmic string loops can contribute significantly to the BAU for $U(1)_{B-L}$ symmetry breaking scale $\eta_{B-L}\gsim 1.7\times 10^{11}\gev$. At the same time, in order for the contribution of decaying $B-L$ cosmic string loops not to exceed the observed baryon-to-photon ratio inferred from the recent WMAP results, the lightest heavy right-handed Majorana neutrino mass $M_1$ must satisfy the constraint $M_1 \leq 2.4 \times 10^{12}(\eta_{B-L}/10^{13}\gev)^{1/2}\gev$. This may have interesting implications for the associated Yukawa couplings in the heavy neutrino sector and consequently for the light neutrino masses generated through see-saw mechanism. |
en |
dc.format.extent |
241904 bytes |
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dc.format.mimetype |
application/pdf |
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dc.language.iso |
en |
en |
dc.publisher |
American Physical Society |
en |
dc.relation.uri |
http://prola.aps.org/abstract/PRD/v70/i8/e083534 |
en |
dc.relation.uri |
http://arxiv.org/abs/hep-ph/0406054 |
en |
dc.subject |
Cosmic Strings |
en |
dc.subject |
Baryon Asymmetry |
en |
dc.subject |
Baryogenesis |
en |
dc.title |
B-L cosmic strings and baryogenesis |
en |
dc.type |
Article |
en |