3,842 research outputs found
Recent developments in rare kaon decays
We discuss issues in rare and radiative kaon decays. The interest is to
extract useful short-distance information and uncover underlying dynamics. We
emphasize channels where either we can understand non-perturbative aspects of
QCD or there is a chance to test the Standard Model.Comment: Invited minireview for Modern Physics Letters A (MPLA), 15 pages, 9
figures, usepackages epsf,colo
Electromagnetic penguin operators and direct CP violation in K --> pi l^+ l^-
Supersymmetric extensions of the Standard Model predict a large enhancement
of the Wilson coefficients of the dimension-five electromagnetic penguin
operators affecting the direct CP violation in K_L --> pi^0 e^+ e^- and the
charge asymmetry in K^\pm --> pi^\pm l^+ l^-.
Here we compute the relevant matrix elements in the chiral quark model and
compare these with the ones given by lattice calculationsComment: 12 pages, JHEP style, gluonic corrections to B_T adde
Radiative Non-Leptonic Kaon Decays
We investigate to what extent DANE will be able to test the Standard
Model in the confinement regime with radiative kaon decays. We concentrate on
processes which can be detected at DANE and we review briefly those
decays where only upper limits can be expected. The Standard Model predictions
for these decays are analyzed in the framework of chiral perturbation theory.Comment: 41 pages, latex file, 10 figures added in a separate uufil
Supersymmetric contributions to direct CP violation in K -> pi pi gamma decays
We analyze the supersymmetric contributions to direct-CP-violating
observables in decays induced by gluino-mediated
magnetic-penguin operators. We find that \epsp_{+-\gamma} and the
differential width asymmetry of decays could
be substantially enhanced with respect to their Standard Model values,
especially in the scenario where \epsp/\eps is dominated by supersymmetric
contributions. These observables could therefore provide a useful tool to
search for New Physics effects in transitions, complementary to
\epsp/\eps and rare decays.Comment: 14 pages, Latex. Numerical error in Eq.(36) corrected, conclusions
unchanged; version to appear in Phys. Lett.
Radiative Four--Meson Amplitudes in Chiral Perturbation Theory
We present a general discussion of radiative four--meson processes to
in chiral perturbation theory. We propose a definition of
``generalized bremsstrahlung'' that takes full advantage of experimental
information on the corresponding non--radiative process. We also derive general
formulae for one--loop amplitudes which can be applied, for instance, to \eta
\ra 3\pi\gamma, \pi \pi \ra \pi \pi \gamma and K \ra 3\pi\gamma.Comment: 8 pages, LaTex file, 1 figure. Full postscript version at this URL
http://hpteor.lnf.infn.it/dafnepapers.htm
A search for Z' in muon neutrino associated charm production
In many extensions of the Standard Model the presence of an extra neutral
boson, Z', is invoked. A precision study of weak neutral-current exchange
processes involving only second generation fermions is still missing. We
propose a search for Z' in muon neutrino associated charm production. This
process only involves Z' couplings with fermions from the second generation. An
experimental method is thoroughly described using an ideal detector. As an
application, the accuracy reachable with present and future experiments has
been estimated.Comment: 13 pages, 3 figures, late
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