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THE CONNECTION BETWEEN LEPTOGENESIS AND NEUTRINO EXPERIMENTS. Alicia Broncano (Universidad Autónoma de Madrid) in collaboration with B.Gavela and E.Jenkins. Cosmological Baryon Asymmetry. Non-zero neutrino masses. Physics beyond the SM (New Physics Scale).
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THE CONNECTION BETWEEN LEPTOGENESIS AND NEUTRINO EXPERIMENTS Alicia Broncano (Universidad Autónoma de Madrid) in collaboration with B.Gavela and E.Jenkins
Cosmological Baryon Asymmetry Non-zeroneutrino masses • Physics beyond the SM (New Physics Scale) SEESAW MODEL(Gell-Mann, Ramond, Slansky, 1979) Two or moresinglet neutrinos with Majorana massesM~ 109-1015 GeV LEPTOGENESIS (Fukugita,Yanagida,1986) B-L and CP violation and out-of-equilibrium Can it be tested in low-energy experiments?
THE SEESAW EFFECTIVE LAGRANGIAN As EW scale, decouples at low energy and can be integrated out Higher dimensional operators suppressed by M
Consider the first term in the series: (Weinberg, 1979) Depends on seesaw parameters Violates L ( DL=2 ) (Generates 2b0n-decay )
generates n-mass when SEESAW MECHANISM
Is possible to determine the seesaw parameters inexperiments on n-masses and mixings? Count how many parameters are in the leptonic Lagrangians of both theories
High energy: 8 moduli + 2 phases • Low energy: 5 moduli + 1 phase
General: Less parameters in that in How difficult is to recover the seesaw parameters a model independent way? Let us consider next term in the expansion
1/M 2term in power series (AB,Gavela,Jenkins,2002) Depends on seesaw parameters only tree-level operator Conserves L
modifies n-kinetic energy when Non diagonal matrix in flavor space Canonical and mass eigenstates basis Majorana mass eigenstates:
Non-unitary mixing matrix CKM-like unitary matrix (from mn-diagonalization) Weak currents are changed Exotic couplings
In two generations 3 moduli and 1 phase Which appear, for instance, in: With , , and Enough low-energy observables 8 moduli + 2 phases
General: Equal parameters in that in • Allows to express the seesaw parameters • …………. .in terms of • . • .
Leptogenesis CP-asymetry (AB,Gavela,Jenkins,2003) • Very complicated function, but exists: • Leptogenesis CP-odd phase function of….all low-energy phases • No CP-phases in and • eigenvalues degenerate • eigenvalues degenerate
Problem: VERY SUPRESSED Experimental bounds: (KARMEN) (NOMAD) (NOMAD) (CHOOZ)
CONCLUSIONS Generic link between low-energy and leptogenesis through the effective seesaw lagrangian to……….……… • Exotic couplings from • Leptogenesis asym. in terms of and • Lepto-phase depends on all low-energy phases • or eigenvalues degenerate difficult to measure
Seesaw model and leptogenesis: • Difficult to reject • Very promising if • Leptonicdmeasured CP-violation • 2b0n-decaydetectedB-L violation Basic ingredients