14767884
Commutators of lepton mass matrices, CP violation, and matter effects in medium-baseline neutrino experiments
We introduce the commutators of lepton mass matrices to describe the phenomenon of lepton flavor mixing, and establish their relations to the effective Hamiltonians responsible for the propagation of neutrinos. The determinants of those commutators an invariant under matter effects, leading to an instructive relationship between the universal CP-violating parameters in vacuum and in matter. in the scenario of low-energy (100 MeV less than or equal toE less than or equal to1 GeV) and medium-baseline (100 km less than or equal toL less than or equal to 400 km) neutrino experiments, we illustrate the features of lepton flavor mixing and CP violation. The terrestrial matter effects on CP- and T-violating asymmetries in nu (e) nu (mu) and )over bar>(e) )over bar>(mu) neutrino oscillations are also discussed. We demonstrate that a relatively pure signal of leptonic CP violation at the percent level can be established from such medium-baseline experiments with low-energy neutrino beams.
8979872
Getting at the Quark Mass Matrices
We present a class of Ansatze for the up and down quark mass matrices which leads approximately to: |V_{us}| \sim \sqrt{m_d / m_s}, |V_{cb}| \sim m_s / m_b, and |V_{ub} / V_{cb}| \sim \sqrt{m_u / m_c}. Sizes of the Kobayashi-Maskawa matrix elements are controlled solely by quark mass ratios. In particular, we introduce no other small parameter and our results do not rely on delicate cancellation.
16484665
How to describe neutrino mixing and CP violation
Abstract We present a classification of possible parametrizations of the 3×3 lepton flavor mixing matrix in terms of the rotation and phase angles. A particular parametrization, which is most convenient to describe the observables of neutrino oscillations and that of the neutrinoless double beta decay, is studied in detail. The possibility to determine the Dirac- and Majorana-type CP-violating phases are also discussed.
119616935
Final-state phase shifts in neutral-B decays to CP eigenstates
Abstract The effect of final-state-interaction phases on CP violation is analyzed for those nonleptonic neutral-B-meson decays to CP eigenstates which occur through the tree-level and the penguin processes. If the measurement of CP -violating asymmetries for these decays is realized both at the Z peak and at the ϒ(4S), we find that the final-state phase shifts can be determined without calculating the corresponding hadronic matrix elements explicitly.
122282326
Direct detection of hot dark matter including light sterile neutrinos
Both active and sterile sub-eV neutrinos can serve for hot dark matter (DM) in the Universe. We consider the beta-decaying (e.g., 3H) and EC-decaying (e.g., 163Ho) nuclei as the most promising targets to capture hot DM in the laboratory. We calculate the capture rates of relic electron neutrinos and antineutrinos against the corresponding beta decay or electron capture (EC) decay backgrounds in different flavor mixing schemes. We stress that such direct measurements of hot DM might not be hopeless in the long term.
121290545
Majorana phases and neutrino-antineutrino oscillations
If massive neutrinos are the Majorana particles, how to pin down the Majorana CP-violating phases will eventually become an unavoidable question relevant to the future neutrino experiments. I argue that a study of neutrino-antineutrino oscillations will greatly help in this regard, although the issue remains purely academic at present. In this talk I first derive the probabilities and CP-violating asymmetries of neutrino-antineutrino oscillations in the three-flavor framework, and then illustrate their properties in two special cases: the normal neutrino mass hierarchy with m(1) = 0 and the inverted neutrino mass hierarchy with m(3) = 0. I demonstrate the significant contributions of the Majorana phases to the CP-violating asymmetries, even in the absence of the Dirac phase.
119592774
SPIN DETERMINATION AND QUANTIZED ALIGNMENT IN THE SUPERDEFORMED BANDS IN DY-152, TB-151, AND GD-150
The spin of the lowest level observed in the superdeformed band in {sup 152}Dy is determined to be {ital I}{sub 0}=25 rather than the previously assigned {ital I}{sub 0}=22. As a result, we have {ital scrI}{sup (1)}{gt}{ital scrI}{sup (2)} and both {ital scrI}{sup (1)} and {ital scrI}{sup (2)} decrease very slowly with rotational frequency. From the spin determination of the two pairs of identical bands in {sup 152}Dy and {sup 151}Tb{sup *}, {sup 151}Tb and {sup 150}Gd{sup *}, evidence has been obtained to support the assumption of quantized alignments in units of {h bar}/2.