TY - JOUR
T1 - Variations on leptogenesis
AU - Sierra, Diego Aristizabal
AU - Losada, Marta
AU - Nardi, Enrico
N1 - Funding Information:
We thank Y. Nir for discussions and for pointing out an error in the first version of the paper. We thank E. Roulet and S. Davidson for discussions. D.A.S. acknowledges M. Hirsch for his help in some of the calculations. D.A.S. is supported by a Spanish Ph.D. fellowship by M.C.Y.T. The work of M.L. is supported in part by Colciencias under contract number 1115-333-18739. The work of E.N. is supported in part by the Istituto Nazionale di Fisica Nucleare (INFN) in Italy, and by Colciencias in Colombia under contract 1115-333-18739.
PY - 2008/1/17
Y1 - 2008/1/17
N2 - We study variations of the standard leptogenesis scenario that can arise if an additional mass scale related to the breaking of some new symmetry (as for example a flavor or the B - L symmetry) is present below the mass MN1 of the lightest right-handed Majorana neutrino. Our scheme is inspired by U (1) models of flavor à la Froggatt-Nielsen, and involves new vectorlike heavy fields F. We show that depending on the specific hierarchy between MN1 and the mass scale of the fields F, qualitatively different realizations of leptogenesis can emerge. We compute the CP asymmetries in N1 decays in all the relevant cases, and we conclude that in most situations leptogenesis could be viable at scales much lower than in the standard scenario.
AB - We study variations of the standard leptogenesis scenario that can arise if an additional mass scale related to the breaking of some new symmetry (as for example a flavor or the B - L symmetry) is present below the mass MN1 of the lightest right-handed Majorana neutrino. Our scheme is inspired by U (1) models of flavor à la Froggatt-Nielsen, and involves new vectorlike heavy fields F. We show that depending on the specific hierarchy between MN1 and the mass scale of the fields F, qualitatively different realizations of leptogenesis can emerge. We compute the CP asymmetries in N1 decays in all the relevant cases, and we conclude that in most situations leptogenesis could be viable at scales much lower than in the standard scenario.
KW - Decays of heavy neutrinos
KW - Flavor symmetries
KW - Right-handed neutrinos
UR - http://www.scopus.com/inward/record.url?scp=37449031066&partnerID=8YFLogxK
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U2 - 10.1016/j.physletb.2007.10.030
DO - 10.1016/j.physletb.2007.10.030
M3 - Article
AN - SCOPUS:37449031066
SN - 0370-2693
VL - 659
SP - 328
EP - 335
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 1-2
ER -