4,527 research outputs found
Semileptonic B to Scalar meson Decays in the Standard Model with Fourth Generation
We study the effects of the fourth generation of quarks on the total
branching ratio and the lepton polarizations in ( = , ) decay. Taking fourth
generation quark mass of about to GeV with the
mixing angle in the range
and using the phase to be %, it is found
that the branching ratio and lepton polarizations are quite sensitive to these
fourth generation parameters. In future the experimental study of this decay
will give us an opportunity to study new physics effects, precisely, to search
for the fourth generation of quarks in an indirect
way.Comment: 15 pages, 7 figures; Modification in the text and figures, version is
closed to the one accepted for publication in Phys. Rev.
Kinematic Self-Similar Solutions of Locally Rotationally Symmetric Spacetimes
This paper contains locally rotationally symmetric kinematic self-similar
perfect fluid and dust solutions. We consider three families of metrics which
admit kinematic self-similar vectors of the first, second, zeroth and infinite
kinds, not only for the tilted fluid case but also for the parallel and
orthogonal cases. It is found that the orthogonal case gives contradiction both
in perfect fluid and dust cases for all the three metrics while the tilted case
reduces to the parallel case in both perfect fluid and dust cases for the
second metric. The remaining cases give self-similar solutions of different
kinds. We obtain a total of seventeen independent solutions out of which two
are vacuum. The third metric yields contradiction in all the cases.Comment: 17 pages, accepted for publication Brazilian J. Physic
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