38,372 research outputs found
Coherent States on Hilbert Modules
We generalize the concept of coherent states, traditionally defined as
special families of vectors on Hilbert spaces, to Hilbert modules. We show that
Hilbert modules over -algebras are the natural settings for a
generalization of coherent states defined on Hilbert spaces. We consider those
Hilbert -modules which have a natural left action from another
-algebra say, . The coherent states are well defined in this
case and they behave well with respect to the left action by .
Certain classical objects like the Cuntz algebra are related to specific
examples of coherent states. Finally we show that coherent states on modules
give rise to a completely positive kernel between two -algebras, in
complete analogy to the Hilbert space situation. Related to this there is a
dilation result for positive operator valued measures, in the sense of Naimark.
A number of examples are worked out to illustrate the theory
Supersymmetric Effects on Isospin Symmetry Breaking and Direct CP Violation in
We argue that one can search for physics beyond the standard model through
measurements of the isospin-violating quantity , its charge conjugate
, and direct CP violation in the partial decay rates of . We illustrate this by working out theoretical profiles of the
charge-conjugate averaged ratio and the CP asymmetry in the
standard model and in some variants of the minimal supersymmetric standard
model. We find that chargino contributions in the large region may
modify the magnitudes and flip the signs of and compared to their standard-model values, providing an
unmistakeable signature of supersymmetry.Comment: 10 pages, 7 figures (requires graphicx
Is Weak Pseudo-Hermiticity Weaker than Pseudo-Hermiticity?
For a weakly pseudo-Hermitian linear operator, we give a spectral condition
that ensures its pseudo-Hermiticity. This condition is always satisfied
whenever the operator acts in a finite-dimensional Hilbert space. Hence weak
pseudo-Hermiticity and pseudo-Hermiticity are equivalent in finite-dimensions.
This equivalence extends to a much larger class of operators. Quantum systems
whose Hamiltonian is selected from among these operators correspond to
pseudo-Hermitian quantum systems possessing certain symmetries.Comment: published version, 10 page
Possible large direct CP asymmetry in hadronic B+- -> \pi+- \eta' decays
We calculate the branching ratio and direct CP asymmetry in nonleptonic two
body B decays B^+- ->\pi^+- \eta'. It is shown that the tree diagram and gluon
fusion mechanism via penguin diagram have comparable contributions to these
decays which, as a result, could provide an interesting venue for investigating
CP violation. Our estimate shows that the direct CP asymmetry in the above
decays could be as large as 75% which along with a branching ratio B(B^-
->\pi^- \eta')=3.4 X 10^{-6} should be accessible to experiment in the near
future.Comment: 13 pages, Revtex, 4 figures (included
Isospin Considerations in Correlations of Pions and mesons
The correlations between a meson and a pion produced nearby in phase
space should respect isospin reflection symmetry . Thus, one
generally expects similar and correlations (non-exotic
channels), and similar and correlations (exotic
channels). Exceptions include (a) fragmentation processes involving exchange of
quarks with the producing system, (b) misidentification of charged kaons as
charged pions, and (c) effects of decay products of the associated
. All of these can affect the apparent signal for correlations of
charged mesons with charged hadrons. The identification of the flavor of
neutral mesons through the decay requires good
particle identification in order that the decay not be
mistaken for , in which case the correlations
of neutral mesons with hadrons can be underestimated.Comment: LaTeX EPSF file; 8 uuencoded figures to be submitted separatel
Decays of mesons with charm quarks on the lattice
We investigate mesons containing charm quarks on fine lattices with a^{-1}
\sim 5 GeV. The quenched approximation is employed using the Wilson gauge
action at \beta = 6.6 and nonperturbatively O(a) improved Wilson quarks. We
present results for decay constants using various interpolating fields and give
preliminary results for form factors of semileptonic decays of D_s mesons to
light pseudoscalar mesons.Comment: 7 pages, 3 figures, talk presented at the XXV International Symposium
on Lattice Field Theory, 30 July - 4 August 2007, Regensburg, German
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