An alternative approach to b->s\gamma in the unconstrained MSSM

The gluino contributions to the $C'_{7,8}$ Wilson coefficients for b->s\gamma are calculated within the unconstrained MSSM. New stringent bounds on the \dRLbs and \dRRbs mass insertion parameters are obtained in the limit in which the SM and SUSY contributions to $C_{7,8}$ approximately cancel. Such a cancellation can plausibly appear within several classes of SUSY breaking models. Assuming this cancellation takes place, we perform an analysis of the b->s\gamma decay. We show that, in the unconstrained MSSM such an alternative is reasonable and it is possible to saturate the b->s\gamma branching ratio and produce a CP asymmetry of up to 20%, from only the gluino contribution to $C'_{7,8}$ coefficients. Using photon polarization a LR asymmetry can be defined that in principle allows the $C_{7,8}$ and $C'_{7,8}$ contributions to the b->s\gamma decay to be disentangled.Comment: 6 pages, 4 eps figure, talk given at the XXXVIIth Rencontres de Moriond (ELECTROWEAK

Why care about (θ13,δ)(\theta_{13},\delta) degeneracy at future neutrino experiments

The presence of several clone solutions in the simultaneous measurement of ($\theta_{13},\delta$) has been widely discussed in literature. Here, after a pedagogical introduction on why these clones arise, we discuss how the clones location in the ($\theta_{13},\delta$) plane change as a function of the physical input pair ($\bar\theta_{13},\bar\delta$). We compare the clone flow of a set of possible future neutrino experiments: the CERN SuperBeam, BetaBeam and Neutrino Factory proposals. We show that the combination of these specific BetaBeam and SuperBeam could not help in solving the degeneracies. The combination of one of them with the Neutrino Factory Golden and Silver channel can, instead, be used to solve completely the eightfold degeneracy.Comment: 7 pages, 12 figures. Talk given at the XXXIXth Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Italy, 21-28 Mar 200

Sum rules for asymptotic form factors in e+e−−>W+W−e^+ e^- -> W^+ W^- scattering

At very large energies and in $SU(2)_L\otimes U(1)_Y$ gauge theories, the trilinear gauge boson vertices relevant for $e^+e^- \to W^+W^-$ scattering are related in a simple way to the gauge boson self-energies. We derive these relations, both from the requirement of perturbative unitarity and from the Ward Identities of the theory. Our discussion shows that, in general, it is never possible to neglect vector boson self-energies when computing the form factors which parametrize the $e^+ e^- \to W^+ W^-$ helicity amplitudes. The exclusion of the self-energy contributions would lead to estimates of the effects wrong by orders of magnitudes. We propose a simple way of including the self-energy contributions in an appropriate definition of the form factors.Comment: 16 pages, latex file, 2 eps figures, need epsfig.st

Generalized Teleportation Protocol

A generalized teleportation protocol (GTP) for N qubits is presented, where the teleportation channels are non-maximally entangled and all the free parameters of the protocol are considered: Alice's measurement basis, her sets of acceptable results, and Bob's unitary operations. The full range of Fidelity (F) of the teleported state and the Probability of Success (P_{suc}) to obtain a given fidelity are achieved by changing these free parameters. A channel efficiency bound is found, where one can determine how to divide it between F and P_{suc}. A one qubit formulation is presented and then expanded to N qubits. A proposed experimental setup that implements the GTP is given using linear optics.Comment: 4 pages, 2 figures, RevTex4, published versio