arXiv subjects

E. Lunghi

Publications and source records attributed to E. Lunghi.

41 records · Page 3Linked to original sources

arXiv2001

General Flavor Blind MSSM and CP Violation

We study the implications on flavor changing neutral current and CP violating processes in the context of supersymmetric theories without a new flavor structure (flavor blind supersymmetry). The low energy parameters are determined by the running of the soft breaking terms from the grand unified scale with SUSY phases consistent with the EDM constraints. We find that the CP asymmetry in b --> s gamma can reach large values potentially measurable at B factories, especially in the low BR(b --> s gamma) region. We perform a fit of the unitarity triangle including all the relevant observables. In this case, no sizeable deviations from the SM expectations are found. Finally we analyze the SUSY contributions to the anomalous magnetic moment of the muon pointing out its impact on the b --> s gamma CP asymmetry and on the SUSY spectrum including chargino and stop masses.

hep-ph↗

arXiv2000

Looking for Novel CP-Violating Effects in B->K^*l^+l^-

The CP-violating asymmetries in the exclusive decay B->K^*l^+l^- (l=e,mu,tau) are predicted to be exceedingly small in the standard model (SM), thereby offering an opportunity to assess various new-physics scenarios. We derive quantitative predictions for various integrated observables in B->K^*mu^+mu^- decay in the presence of physics beyond the SM with additional CP phases and an extended operator basis. In particular, a model-independent analysis of CP asymmetries that require the presence of unitarity phases, in addition to CP violation, is performed. We find that in the low dimuon invariant mass region 2m_mu s gamma rate and the upper limit on BR(B^0->K^{*0}mu^+mu^-), CP-violating effects of a few per cent are estimated, even in the presence of new physics with CP phases of O(1). By contrast, in the high dimuon invariant mass region M_{psi'}<M_{mu^+mu^-}<(M_B-M_{K^*}) significant CP-violating effects are possible. Given a branching ratio of 1.8 x 10^{-6}, the CP asymmetries can be quite substantial (\sim 20% or more), and thus may serve as a means of discovering physics transcending the SM.

hep-ph↗

arXiv1999

B -> Xs l+ l- decays in supersymmetry

We study the semileptonic decays B -> Xs e+ e- and B -> Xs mu+ mu- in generic supersymmetric extensions of the Standard Model. SUSY effects are parameterized using the mass insertion approximation formalism and differences with the Constrained MSSM results are pointed out. Constraints on SUSY contributions coming from other processes (e.g. b -> s photon) are taken into account. Chargino and gluino contributions to photon and Z-mediated decays are computed and non-perturbative corrections are considered. We find that the integrated branching ratios and the asymmetries can be strongly modified. Moreover, the behavior of the differential Forward-Backward asymmetry remarkably changes with respect to the Standard Model expectation.

hep-ph↗

arXiv1999

B -> Xs l+ l- in SUSY

We study the semileptonic decays B -> Xs e+ e-, B -> Xs mu+ mu- in generic supersymmetric extensions of the Standard Model. SUSY effects are parameterized using the mass insertion approximation formalism and differences with MSSM results are pointed out. Constraints on SUSY contributions coming from other processes (e.g. b -> s gamma) are taken into account. Chargino and gluino contributions to photon and Z-mediated decays are computed and non-perturbative corrections are considered. We find that the integrated branching ratios and the asymmetries can be strongly modified. Moreover, the behavior of the differential Forward-Backward asymmetry remarkably changes with respect to the Standard Model expectation.

hep-ph↗

arXiv1997

Neutrino masses and flavor symmetries

The problem of neutrino masses and mixing angles is analysed in a class of supersymmetric grand unified models, with SO(10) gauge symmetry and global U(2) flavour symmetry. Adopting the seesaw mechanism for the generation of the neutrino masses, one obtains a mass matrix for the left-handed neutrinos which is directly related to the parameters of the charged sector, while the unknown parameters of the right-handed Majorana mass matrix are inglobed in a single factor.

hep-ph↗