5,381 research outputs found
Bs decays: CP asymmetries in left-right models with spontaneous CP violation
We present the contributions of new CP phases in CP asymmetries of two-body
neutral decays coming from a left--right model with spontaneous CP
violation. Large deviations from the Standard Model predictions can be
accommodated in a natural way by this type of models. The new physics effects
on the mixing, width difference and decays are analysed. In particular, we show
how the measurement of the angle in electroweak penguin-dominated
processes can be largely affected.Comment: 6 pages, Revtex, epsfig. Talk given at 34th Rencontres de Moriond:
Electroweak Interactions and Unified Theories, Les Arcs, France, 13-20 Mar
199
Huge right-handed current effects in B->K*(K pi)l+l- in supersymmetry
Transverse asymmetries in the decay B->K*(K pi)l+l- are an extremely
sensitive probe of right-handed flavour-changing neutral currents. We show how
to include the contribution from the chiral partner of the electromagnetic
operator on the transverse asymmetries at NLO in QCD factorization. We then
consider supersymmetric models with non-minimal flavour violation in the
down-squark sector. We include all the relevant experimental constraints and
present a numerical formula for B->Xs gamma that takes into account the most
recent NNLO calculations. We show that the flavour-changing parameters of these
models are poorly constrained by present data and allow for large effects on
the transverse asymmetries that we consider.Comment: 12 pages, 4 figures, version to appear on JHE
Five-leg photon-neutrino interactions
In a first part, we justify the feasibility of substituting a photon leg by a
neutrino current in the Euler-Heisenberg Lagrangian to obtain an effective
Lagrangian for the process and its crossed
reactions.
We establish the link between these processes and the four-photon scattering
in both the Standard Model and the effective theory. As an application, we
compute in this effective theory the processes
and and show how to use the
results as a check. We settle the question of the
disagreement between two computations in the literature concerning the reaction
. In the second part, we present results of
the direct computation of the photon-neutrino five-leg processes in the
Standard Model, discuss possible astrophysical implications of our results, and
provide simple fits to the exact expressions.Comment: 6 pages, axodraw, ltwol2e, 5 figures, contributed paper to the 29th
International Conference on High Energy Physics (Vancouver
- …