Maurizio Lusignoli

NEUTRINO DECAY AND ATMOSPHERIC NEUTRINOS

Abstract We reconsider neutrino decay as an explanation for atmospheric neutrino observations. We show that if the mass-difference relevant to the two mixed states νμ and ντ is very small ( −4 eV 2 ) , then a very good fit to the observations can be obtained with decay of a component of νμ to a sterile neutrino and a Majoron. We discuss how the K2K and MINOS long-baseline experiments can distinguish the decay and oscillation scenarios.

Nonleptonic weak decays of charmed mesons

A previous analysis of two-body Cabibbo-allowed nonleptonic decays of [ital D][sup 0] mesons and of Cabibbo-allowed and first-forbidden decays of [ital D][sup +] and [ital D][sub [ital s]][sup +] has been adjourned using more recent experimental data and extended to the Cabibbo-forbidden decays of [ital D][sup 0]. Annihilation and [ital W]-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental data, which show large flavor SU(3) violations. New fitting parameters are necessary to describe rescattering effects for Cabibbo-forbidden [ital D][sup 0] decays, given the lack of experimental information on isoscalar resonances. We keep their number to a minimum, three, using phenomenologically based considerations. We also discuss [ital CP]-violating asymmetries.

Mixing and CP violation in K- and B-mesons: a lattice QCD point of view

Abstract We have analyzed K 0 − K 0 and B 0 − B 0 mixing on the basis of the most recent experimental results and theoretical lattice determination of the relevant matrix elements. We find that a top mass larger than 140 GeV and ƒ B ⩾ 200 MeV , as suggested by recent lattice calculations, imply a CP -violating asymmetry in B → J/ Ψ + K s decays much larger than previously estimated. We also report the corresponding theoretical prediction for e / e , for which rather large experimental and theoretical uncertainties still exist.

B(c) decays

AbstractTheoretical predictions on decay properties of the simplest particle containing more than one heavy quark, the pseudoscalarn

Instability of the invisible axion

(bar bc)

CP violating asymmetries in charged D meson decays

n mesonBc+, are presented. Some channels that should present a distinctive signature are discussed in more detail.

Exotic Higgs production at e+e− colliders

Abstract A global previous analysis of two-body nonleptonic decays of D mesons has been extended to the decays involving light scalar mesons. The allowance for final state interaction also in nonresonant channels provides a fit of much improved quality and with less symmetry breaking in the axial charges. We give predictions for about 50 decay branching ratios yet to be measured. We also discuss long distance contributions to the difference ΔΓ between the D S and D L widths.

Telling three from four neutrinos at the neutrino factory

Abstract We show that small explicit violations of the Peccei-Quinn symmetry, such as cpuld be expected as remnants of physics at the Planck scale, have dramatic effects for invisible axion models.