Abstract
We perform a detailed analysis of thermal leptogenesis in the framework of seesaw models which approximately conserve lepton number. These models are known to allow for large Yukawa couplings and a low seesaw scale in agreement with neutrino mass constraints, and hence to lead to large lepton flavour violating rates that can be probed experimentally. Although large Yukawa couplings lead to (inverse) decay rates much larger than the Hubble expansion rate, we show that the leptogenesis washout induced is generically small if the mass splitting between the right-handed neutrinos is small enough. As a result, large lepton flavour violating rates are compatible with successful leptogenesis. We emphasize that this scenario does not require any particular flavour structure. A small splitting is natural and radiatively stable in this context because it is protected by the lepton number symmetry.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
M. Fukugita and T. Yanagida, Baryogenesis without grand unification, Phys. Lett. B 174 (1986) 45 [SPIRES].
P. Minkowski, μ → eγ at a rate of one out of 1-billion muon decays?, Phys. Lett. B 67 (1977) 421 [SPIRES].
T. Yanagida, Horizontal symmetry and masses of neutrinos, in proceedings of the Workshop on Unified Theories and Baryon Number in the Universe, Tsukuba, Japan (1979), O. Sawada and A. Sugamoto eds., KEK, Japan (1979), pag 95.
M. Gell-Mann, P. Ramond and R. Slansky, Supergravity, North Holland, Amsterdam Netherlands (1979), pag. 315.
S.L. Glashow, 1979 Cargese summer institute on quarks and leptons, Plenum Press, New York U.S.A. (1980), pag 687.
R.N. Mohapatra and G. Senjanović, Neutrino mass and spontaneous parity nonconservation, Phys. Rev. Lett. 44 (1980) 912 [SPIRES].
J.R. Ellis and M. Raidal, Leptogenesis and the violation of lepton number and CP at low energies, Nucl. Phys. B 643 (2002) 229 [hep-ph/0206174] [SPIRES].
S. Davidson and A. Ibarra, Determining seesaw parameters from weak scale measurements?, JHEP 09 (2001) 013 [hep-ph/0104076] [SPIRES].
D. Wyler and L. Wolfenstein, Massless neutrinos in left-right symmetric models, Nucl. Phys. B 218 (1983) 205 [SPIRES].
R.N. Mohapatra and J.W.F. Valle, Neutrino mass and baryon-number nonconservation in superstring models, Phys. Rev. D 34 (1986) 1642 [SPIRES].
G.C. Branco, W. Grimus and L. Lavoura, The seesaw mechanism in the presence of a conserved lepton number, Nucl. Phys. B 312 (1989) 492 [SPIRES].
M.C. Gonzalez-Garcia and J.W.F. Valle, Fast decaying neutrinos and observable flavor violation in a new class of majoron models, Phys. Lett. B 216 (1989) 316 [SPIRES].
J. Kersten and A.Y. Smirnov, Right-handed neutrinos at LHC and the mechanism of neutrino mass generation, Phys. Rev. D 76 (2007) 073005 [arXiv:0705.3221] [SPIRES].
A. Abada, C. Biggio, F. Bonnet, M.B. Gavela and T. Hambye, Low energy effects of neutrino masses, JHEP 12 (2007) 061 [arXiv:0707.4058] [SPIRES].
M. Shaposhnikov, A possible symmetry of the υMSM, Nucl. Phys. B 763 (2007) 49 [hep-ph/0605047] [SPIRES].
M.B. Gavela, T. Hambye, D. Hernandez and P. Hernández, Minimal flavour seesaw models, JHEP 09 (2009) 038 [arXiv:0906.1461] [SPIRES].
A. Pilaftsis, CP violation and baryogenesis due to heavy Majorana neutrinos, Phys. Rev. D 56 (1997) 5431 [hep-ph/9707235] [SPIRES].
A. Pilaftsis and T.E.J. Underwood, Resonant leptogenesis, Nucl. Phys. B 692 (2004) 303 [hep-ph/0309342] [SPIRES].
M. Flanz, E.A. Paschos, U. Sarkar and J. Weiss, Baryogenesis through mixing of heavy Majorana neutrinos, Phys. Lett. B 389 (1996) 693 [hep-ph/9607310] [SPIRES].
L. Covi and E. Roulet, Baryogenesis from mixed particle decays, Phys. Lett. B 399 (1997) 113 [hep-ph/9611425] [SPIRES].
J. Liu and G. Segre, Reexamination of generation of baryon and lepton number asymmetries by heavy particle decay, Phys. Rev. D 48 (1993) 4609 [hep-ph/9304241] [SPIRES].
M. Flanz, E.A. Paschos and U. Sarkar, Baryogenesis from a lepton asymmetric universe, Phys. Lett. B 345 (1995) 248 [hep-ph/9411366] [SPIRES].
L. Covi, E. Roulet and F. Vissani, CP violating decays in leptogenesis scenarios, Phys. Lett. B 384 (1996) 169 [hep-ph/9605319] [SPIRES].
T. Asaka and S. Blanchet, Leptogenesis with an almost conserved lepton number, Phys. Rev. D 78 (2008) 123527 [arXiv:0810.3015] [SPIRES].
A. Pilaftsis and T.E.J. Underwood, Electroweak-scale resonant leptogenesis, Phys. Rev. D 72 (2005) 113001 [hep-ph/0506107] [SPIRES].
W. Buchmüller and M. Plümacher, CP asymmetry in Majorana neutrino decays, Phys. Lett. B 431 (1998) 354 [hep-ph/9710460] [SPIRES].
G.F. Giudice, A. Notari, M. Raidal, A. Riotto and A. Strumia, Towards a complete theory of thermal leptogenesis in the SM and MSSM, Nucl. Phys. B 685 (2004) 89 [hep-ph/0310123] [SPIRES].
W. Buchmüller, P. Di Bari and M. Plümacher, Leptogenesis for pedestrians, Ann. Phys. 315 (2005) 305 [hep-ph/0401240] [SPIRES].
A. Anisimov, A. Broncano and M. Plümacher, The CP-asymmetry in resonant leptogenesis, Nucl. Phys. B 737 (2006) 176 [hep-ph/0511248] [SPIRES].
M.C. Gonzalez-Garcia, J. Racker and N. Rius, Leptogenesis without violation of B-L, JHEP 11 (2009) 079 [arXiv:0909.3518] [SPIRES].
S. Antusch, S. Blanchet, M. Blennow and E. Fernandez-Martinez, Non-unitary leptonic mixing and leptogenesis, JHEP 01 (2010) 017 [arXiv:0910.5957] [SPIRES].
Particle Data Group collaboration, C. Amsler et al., Review of particle physics, Phys. Lett. B 667 (2008) 1 [SPIRES].
T.P. Cheng and L.-F. Li, μ → eγ in theories with Dirac and Majorana neutrino mass terms, Phys. Rev. Lett. 45 (1980) 1908 [SPIRES].
S. Antusch, C. Biggio, E. Fernandez-Martinez, M.B. Gavela and J. Lopez-Pavon, Unitarity of the leptonic mixing matrix, JHEP 10 (2006) 084 [hep-ph/0607020] [SPIRES].
J.A. Casas and A. Ibarra, Oscillating neutrinos and μ → e, γ, Nucl. Phys. B 618 (2001) 171 [hep-ph/0103065] [SPIRES].
G.L. Fogli, E. Lisi, A. Marrone, A. Palazzo and A.M. Rotunno, SNO, KamLAND and neutrino oscillations: θ 13, arXiv:0905.3549 [SPIRES].
WMAP collaboration, E. Komatsu et al., Five-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: cosmological interpretation, Astrophys. J. Suppl. 180 (2009) 330 [arXiv:0803.0547] [SPIRES].
A. Abada, C. Biggio, F. Bonnet, M.B. Gavela and T. Hambye, μ → eγ and τ → eγ decays in the fermion triplet seesaw model, Phys. Rev. D 78 (2008) 033007 [arXiv:0803.0481] [SPIRES].
Y. Burnier, M. Laine and M. Shaposhnikov, Baryon and lepton number violation rates across the electroweak crossover, JCAP 02 (2006) 007 [hep-ph/0511246] [SPIRES].
E. Fernandez-Martinez, M.B. Gavela, J. Lopez-Pavon and O. Yasuda, CP-violation from non-unitary leptonic mixing, Phys. Lett. B 649 (2007) 427 [hep-ph/0703098] [SPIRES].
S. Antusch, M. Blennow, E. Fernandez-Martinez and J. Lopez-Pavon, Probing non-unitary mixing and CP-violation at a neutrino factory, Phys. Rev. D 80 (2009) 033002 [arXiv:0903.3986] [SPIRES].
F. del Aguila and J.A. Aguilar-Saavedra, Electroweak scale seesaw and heavy Dirac neutrino signals at LHC, Phys. Lett. B 672 (2009) 158 [arXiv:0809.2096] [SPIRES].
F. del Aguila, J.A. Aguilar-Saavedra and R. Pittau, Heavy neutrino signals at Large Hadron Colliders, JHEP 10 (2007) 047 [hep-ph/0703261] [SPIRES].
T. Hambye, Y. Lin, A. Notari, M. Papucci and A. Strumia, Constraints on neutrino masses from leptogenesis models, Nucl. Phys. B 695 (2004) 169 [hep-ph/0312203] [SPIRES].
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Blanchet, S., Hambye, T. & Josse-Michaux, FX. Reconciling leptogenesis with observable μ → eγ rates. J. High Energ. Phys. 2010, 23 (2010). https://doi.org/10.1007/JHEP04(2010)023
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP04(2010)023