37,404 research outputs found
Charmless decays B -> PP, PV, and effects of new strong and electroweak penguins in Topcolor-assisted Technicolor model
Based on the low energy effective Hamiltonian with generalized factorization,
we calculate the new physics contributions to the branching ratios and
CP-violating asymmetries of the two-body charmless hadronic decays from the new strong and electroweak penguin diagrams in the TC2 model. The
top-pion penguins dominate the new physics corrections, and both new gluonic
and electroweak penguins contribute effectively to most decay modes. For
tree-dominated decay modes the new physics
corrections are less than 10%. For decays , ,
, the new physics enhancements can be rather large (from to ) and are insensitive to the variations of , , and
within the reasonable ranges. For decays ,
, and , is
strongly dependent: varying from -90% to in the range
of . The new physics corrections to the CP-violating
asymmetries vary greatly for different B decay channels. For
five measured CP asymmetries of decays,
is only about 20% and will be masked by large
theoretical uncertainties. The new physics enhancements to interesting decays are significant in size (), insensitive to the
variations of input parameters and hence lead to a plausible interpretation for
the unexpectedly large decay rates. The TC2 model predictions
for branching ratios and CP-violating asymmteries of all fifty seven decay modes are consistent with the available data within one or two
standard deviations.Comment: Latex file, 56 pages with 11 ps and eps figures. to be published in
Eur.Phys.J.
The role of inter-well tunneling strength on coherence dynamics of two-species Bose-Einstein condensates
Coherence dynamics of two-species Bose-Einstein condensates in double wells
is investigated in mean field approximation. We show that the system can
exhibit decoherence phenomena even without the condensate-environment coupling
and the variation tendency of the degree of coherence depends on not only the
parameters of the system but also the initial states. We also investigate the
time evolution of the degree of coherence for a Rosen-Zener form of tunneling
strength, and propose a method to get a condensate system with certain degree
of coherence through a time-dependent tunneling strength
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