1,302 research outputs found
CP Violation in Mixing
The existence of mixing at a detectable level requires
new physics, which effectively yields a superweak interaction.
In general this interaction may involve significant CP violation. For small
values of the mixing it may be much easier to detect the CP-violating part of
the mixing than the CP-conserving part.Comment: 3 pages, latex, no figure
Consequences of Approximate Symmetry of the Neutrino Mass Matrix
Assuming that the neutrino mass matrix is dominated by a term with the
permutation symmetry it is possible to explain
neutrino data only if the masses are quasi-degenerate. A sub-dominant term with
an approximate symmetry leads to an approximate tri-bimaximal form.
Experimental consequences are discussed.Comment: 7 pages, 2 figures, 1 table, RevTe
CP Violation
Three possibilities for the origin of CP violation are discussed: (1) the
Standard Model in which all CP violation is due to one parameter in the CKM
matrix, (2) the superweak model in which all CP violation is due to new physics
and (3) the Standard Model plus new physics. A major goal of B physics is to
distinguish these possibilities. CP violation implies time reversal violation
(TRV) but direct evidence for TRV is difficult to obtain.Comment: 13 pages, to be published in Lecture Notes of TASI-2000, edited by
Jonathan L. Rosner, World Scientific, 200
Toward a Neutrino Mass Matrix
One may identify the general properties of the neutrino mass matrix by
generating many random mass matrices and testing them against the results of
the neutrino experiments.Comment: 3 pages, 1 figure, talk at DPF200
Is really related to the solar neutrino solutions?
It has been said that the measurements of in the lepton flavor
mixing matrix would help discriminate between the possible solar neutrino
solutions under the natural conditions with the neutrino mass hierarchies of
and , where is the -th
generation neutrino absolute mass. However, it is not true, and the relation
between and obtained by Akhmedov, Branco, and
Rebelo is trivial in actual. We show in this paper that the value of
cannot predict the solar neutrino solutions without one additional nontrivial
condition.Comment: 7pages, no figur
Relating the scalar flavour-changing neutral couplings to the CKM matrix
We build a class of two-Higgs-doublet models in which the flavour-changing
couplings of the neutral scalars are related in an exact way to elements of the
quark mixing matrix. In this framework, we explore the different possibilities
for CP violation and find some interesting scenarios, like a realization of the
superweak idea without CP violation in the -meson system. In another
scenario the neutral scalars can be relatively light, and their contributions
to the -- transitions can alter the standard-model predictions
for CP violation in that system.Comment: 12 pages LATEX, no figure
Neutrinoless Double Beta Decay and CP Violation
We study the relation between the Majorana neutrino mass matrices and the
neutrinoless double beta decay when CP is not conserved. We give an explicit
form of the decay rate in terms of a rephasing invariant quantity and
demonstrate that in the presence of CP violation it is impossible to have
vanishing neutrinoless double beta decay in the case of two neutrino
generations (or when the third generation leptons do not mix with other leptons
and hence decouple).Comment: 9 pages, UTPT-93-1
Comment on ``Neutrino masses and mixing angles in a predictive theory of fermion masses''
In the extension of the Dimopoulos--Hall--Raby model of the fermion mass
matrices to the neutrino sector, there is an entry in the up-quark and neutrino
Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a
{\bf 120}, instead of a {\bf 10} or a {\bf 126}, of SO(10). Although this
assumption leads to an extra undetermined complex parameter in the model, the
resulting lepton mixing matrix exhibits the remarkable feature that the does not mix with the other two neutrinos. Making a reasonable
assumption about the extra parameter, we are able to fit the large-mixing-angle
MSW solution of the solar-neutrino problem, and we obtain eV, the right mass range to close the Universe. Other possibilities for
explaining the solar-neutrino deficit are also discussed.Comment: standard LATEX, 6 pages, 2 figures available from the authors, report
No. CMU-HEP93-20 and DOE-ER/40682-4
Probing neutrino oscillations jointly in long and very long baseline experiments
We examine the prospects of making a joint analysis of neutrino oscillation
at two baselines with neutrino superbeams. Assuming narrow band superbeams and
a 100 kt water Cerenkov calorimeter, we calculate the event rates and
sensitivities to the matter effect, the signs of the neutrino mass differences,
the CP phase and the mixing angle \theta_{13}. Taking into account all possible
experimental errors under general consideration, we explored the optimum cases
of narrow band beam to measure the matter effect and the CP violation effect at
all baselines up to 3000 km. We then focus on two specific baselines, a long
baseline of 300 km and a very long baseline of 2100 km, and analyze their joint
capabilities. We found that the joint analysis can offer extra leverage to
resolve some of the ambiguities that are associated with the measurement at a
single baseline.Comment: 23 pages, 11 figure
Desperately Seeking Non-Standard Phases via Direct CP Violation in Process
Attributing the recent CLEO discovery of to originate
(primarily) from the fragmentation of an off-shell gluon () via , , we emphasize that many such states () should
materialize. Indeed the hadronic fragments () of states are closely
related to those seen in . A particular
final state of considerable interest is . Signals from such states
in decays can be combined to provide a very sensitive search for CP
violating phase(s) from non-standard physics. The method should work even if
the contribution of these source(s) to the rates is rather small () to
the point that a comparison between theory and experiment may find it extremely
difficult to reveal the presence of such a new physics.Comment: 16 pages, 5 figure
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