7,266 research outputs found
Neutrino Mixing and CP Violation in Matter
Within the framework of three lepton families I present a transparent
analytical relationship between the neutrino mixing and CP-violating parameters
in vacuum and thos in matter. Such a model- and parametrization-independent
result will be particularly useful to recast the fundamental lepton flavor
mixing matrix from the future long-baseline neutrino experiments.Comment: Talk given at the 3rd International Symposium on Symmetries in
Subatomic Physics, Adelaide, Australia, March 13 - 17, 2000; to appear in the
proceeding
Hierarchical Neutrino Masses and Large Mixing Angles from the Fritzsch Texture of Lepton Mass Matrices
We show that the Fritzsch texture of lepton mass matrices can naturally lead
to the bi-large flavor mixing pattern, if three neutrinos have a normal but
weak mass hierarchy (typically, ). The
effective mass of the tritium beta decay and that of the neutrinoless double
beta decay are too small to be observable in this ansatz, but CP violation at
the percent level is allowed and could be measured in long-baseline neutrino
oscillations.Comment: LaTex 15 pages (5 PS figures). More discussions adde
Towards Isolation of New Physics in B^0_s-\bar{B}^0_s Mixing
In many extensions of the standard model, new physics is possible to
contribute significantly to B^0_s-\bar{B}^0_s mixing. We show that the effect
of new physics, both its phase information and its magnitude, can be isolated
from measurements of CP asymmetries in the semileptonic B_s transitions and in
some nonleptonic B_s decays into hadronic CP eigenstates. We also find that the
rates of CP-forbidden decays at the \Upsilon (5S) resonance are not suppressed
by the large B_s mass difference, thus they can be used to extract the
CP-violating phase of new physics in either B^0_s-\bar{B}^0_s or K^0-\bar{K}^0
mixing.Comment: Big Latex 11 page
Low-energy limits on heavy Majorana neutrino masses from the neutrinoless double-beta decay and non-unitary neutrino mixing
In the type-I seesaw mechanism, both the light Majorana neutrinos (\nu_1,
\nu_2, \nu_3) and the heavy Majorana neutrinos (N_1, ..., N_n) can mediate the
neutrinoless double-beta (0\nu\beta\beta) decay. We point out that the
contribution of \nu_i to this 0\nu\beta\beta process is also dependent on the
masses M_k and the mixing parameters R_{ek} of N_k as a direct consequence of
the exact seesaw relation, and the effective mass term of \nu_i is in most
cases dominant over that of N_i. We obtain a new bound |\sum R^2_{ek} M_k| <
0.23 eV (or < 0.85 eV as a more conservative limit) at the 2\sigma level, which
is much stronger than |\sum R^2_{ek} M^{-1}_k| < 5 \times 10^{-8} GeV^{-1} used
in some literature, from current experimental constraints on the 0\nu\beta\beta
decay. Taking the minimal type-I seesaw scenario for example, we illustrate the
possibility of determining or constraining two heavy Majorana neutrino masses
by using more accurate low-energy data on lepton number violation and
non-unitarity of neutrino mixing.Comment: RevTeX 12 pages, 1 PS figure. Accepted for publication in PL
- …