58,839 research outputs found
Quasi-Inclusive and Exclusive decays of to
We consider the effective Hamiltonian of four quark operators in the Standard
Model in the exclusive and quasi-inclusive decays of the type , , where contains a single Kaon. Working
in the factorization assumption we find that the four quark operators can
account for the recently measured exclusive decays
and for appropriate choice of form factors but cannot explain the
large quasi-inclusive rate.Comment: Calculation of added and the correct BSW form factors
have been used. Latex 13 papges, 1 figur
Convergence of Adaptive Finite Element Approximations for Nonlinear Eigenvalue Problems
In this paper, we study an adaptive finite element method for a class of a
nonlinear eigenvalue problems that may be of nonconvex energy functional and
consider its applications to quantum chemistry. We prove the convergence of
adaptive finite element approximations and present several numerical examples
of micro-structure of matter calculations that support our theory.Comment: 24 pages, 12 figure
Constraints on the phase and new physics from Decays
Recent results from CLEO on indicate that the phase may
be substantially different from that obtained from other fit to the KM matrix
elements in the Standard Model. We show that extracted using is sensitive to new physics occurring at loop level. It provides
a powerful method to probe new physics in electroweak penguin interactions.
Using effects due to anomalous gauge couplings as an example, we show that
within the allowed ranges for these couplings information about
obtained from can be very different from the Standard
Model prediction.Comment: Revised version with analysis done using new data from CLEO. RevTex,
11 Pages with two figure
Concurrence of superposition
The bounds on concurrence of the superposition state in terms of those of the
states being superposed are studied in this paper. The bounds on concurrence
are quite different from those on the entanglement measure based on von Neumann
entropy (Phys. Rev. Lett. 97, 100502 (2006)). In particular, a nonzero lower
bound can be provided if the states being superposed are properly constrained.Comment: 4 page
Topological phase due to electric dipole moment and magnetic monopole interaction
We show that there is an anologous Aharonov-Casher effect on a neutral
particle with electric dipole moment interacting with a magnetic filed produced
by magnetic monopoles.Comment: 8 page
in the Standard Model
In this paper we investigate the possibility of studying form
factor using the semi-inclusive decays . In general
semi-inclusive decays involve several hadronic parameters. But for
decays we find that in the factorization
approximation, the only unknown hadronic parameters are the form factors
. Therefore these form factors can be studied in decays. Using theoretical model calculations for the form
factors the branching ratios for and
, with the cut GeV, are
estimated to be in the ranges of and ,
respectively, depending on the value of . The combined branching ratio
for is about and is insensitive to . We also discuss CP
asymmetries in these decay modes.Comment: RevTex 8 pages and two figure
Tachyon field inspired dark energy and supernovae constraints
The tachyon field in cosmology is studied by applying the generating function
method to obtain exact solutions. The equation of state parameter of the
tachyon field is , which can be expressed as a
function in terms of the redshift . Based on these solutions, we propose
some tachyon-inspired dark energy models to explore the properties of the
corresponding cosmological evolution. The explicit relations between Hubble
parameter and redshift enable us to test the models with SNe Ia data sets
easily. In the current work we employ the SNe Ia data with the parameter
measured from the SDSS and the shift parameter from
WMAP observations to constrain the parameters in our models.Comment: 6 pages, 2 figures; v2: accepted by IJMP
Anomalous Phase Transition in Strained SrTiO Thin Films
We have studied the cubic to tetragonal phase transition in epitaxial
SrTiO films under various biaxial strain conditions using synchrotron X-ray
diffraction. Measuring the superlattice peak associated with TiO octahedra
rotation in the low temperature tetragonal phase indicates the presence of a
phase transition whose critical temperature is a strong function of strain,
with T as much as 50K above the corresponding bulk temperature.
Surprisingly, the lattice constants evolve smoothly through the transition with
no indication of a phase change. This signals an important change in the nature
of the phase transition due to the epitaxy strain and substrate clamping
effect. The internal degrees of freedom (TiO rotations) have become
uncoupled from the overall lattice shape.Comment: 4 pages, 3 figures, REVTeX
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