A.I. Sanda

A prediction for dΓ(b→sℓℓdq2 including the long-distance effects

Abstract We point out that both long- and short-distance effects of b→ s l l (l= e , μ) can be computed. The long-distance contribution, mainly due to Ψ and Ψ′ resonances, is shown to give a dominant contribution to Br(b → s l l ). This contribution is predicted to be Br(b → s Ψ→ sl l =0.59×10 −3 , Br(b → sΨ ′→ sl l )=2.5×10 −5 . The long-distance effect also causes a remarkable deviation of the q 2 (q 2 : invariant l l mass-squared ) distribution from what is expected from the short-distance effect alone.

CP violation in heavy flavor decays: Predictions and search strategies

We present a comprehensive analysis of the phenomenology relevant for CP violation in exclusive B and D decays. Some of the CP asymmetries can be calculated rather reliably in the standard model, while others contain large uncertainties. We point out that studies of inclusive decays will have to deal with partial cancellations occurring between different exclusive channels. None of the measurements will be easy. Yet a realistic evaluation of the promise the various searches hold out cannot be given at present; first, one has to build a data base on the production and decay properties of heavy flavor decays. We try to identify the required information.

On D0−D0 mixing and CP violation

Abstract Observable D0− D 0 mixing would strongly indicate New Physics. The MARK III group has found intriguing, though so far marginal evidence for Prob.(D0→ D 0) ∼ 1%. Effects due to quantum statistics are highly important in properly interpreting the signal and treating the background. Here these effects are analysed in general. D0− D 0 mixing will also lead to like-sign dileptons in deep inelastic neutrino nucleon scattering. We point out that if Prob.(D0→ D 0) ∼ 1% holds then certain decays like D0→KSπ0 can exhibit CP asymmetries on the percent level. Extended Higgs (or technicolour) models with flavour changing neutral currents would be the only good candidates. Therefore we urge further experimental study along this direction.

From a new smell to a new flavour −BdBd mixing, CP violation and new physics☆

Abstract Using the preliminary data on B d B d mixing from ARGUS, and the standard model with three families, we infer a lower bound on the top quark mass of 50–70 GeV; also, B s B s mixing has to be close to maximal. We discuss how the prospects for observing CP violation in B 0 decays are enhanced and sketch alternative scenarios for new physics.

An estimate of the long-distance effects in the KL-KS mass difference

Abstract We compute 2 π , π 0 , η , η ′, ϱ , ω , φ contributions to the K L -K S mass difference using a dispersion relation and current algebra, together with experimental information on S-wave ππ phase shifts and K L , π 0 , η , η ′ → γγ decays. Our result is that hadronic contributions are indeed important, i.e., D = 1.54±1.40 or 0.56±1.26 with Δm K = ( Δm ) box + DΔm K . The two values for D result from two different sets of experimental data on S-wave ππ phase shift.

On directCPviolation in Kπ’s versus π’s decays

Abstract We discuss a class of decay modes for charged as well as neutral B mesons where directCPviolation could produce asymmetries of the order of a few percent. Even an asymmetry as large as 10% is conceivable though admittedly optimistic. Two essential ingredients for such an asymmetry are the presence of theV(ub) coupling and the intervention of nontrivial final state interactions; these two elements are also at the origin of large numerical uncertainties in the predictions. The third essential ingredient is the observation that D0 and D ¯ 0 mesons cannot be distinguished as a matter of principle if they decay into Ks + pions. Such asymmetries can be searched for equally well on and off the Υ (4S) resonance.

Hadronic decay of τ

Abstract We present predictions for invariant mass distributions of the pions in τ → ν +2 π and τ → ν +4 π as well as improved predictions for hadronic decay rates of τ. We discuss a number of predictions which, if contradicted by τ decays, will imply the existence of a new weak interaction.

Gauge theory predictions for the electron-nucleus parity violating neutral current interaction

Abstract The parity violating electron-nucleus current interactions of three distinct gauge models are presented, including the dominant radiative corrections. Their predictions for atomic transition and polarized electron scattering experiments are illustrated. We show that even models in which the electrons neutral current coupling is pure vector or in which parity is conserved by the neutral currents in lowest order can predict sizeable parity violating effects as a result of radiative corrections.

CP violation with polarized Z0

Abstract The forward-backward asymmetry in polarized e + e − annihilation at the Z 0 resonance separates particle from antiparticle. This separation facilitates CP violation measurements in neutral B meson decays. The final states of those decays can either be CP eigenstates or not. This note discusses the CP asymmetries expected for the general final state.

Isospin invariance, CP violation and B−B̄ mixing

Abstract With large B 0 −B 0 mixing, the CP asymmetry of certain B decays become nearly maximal. However, the clear identification of relevant B meson decays required for experimental observation of such effects is difficult. We point out that symmetry relations among various B meson decay channels lead to additional constraints which can be useful in extracting CP violating amplitudes. As an example, we consider decay amplitudes to final states containing both a J/ψ and a K S , whose interference terms provide information on CP violation. We show that these decays are ΔI =0 transitions and obtain isospin relations between the direct terms in the amplitude and experimental results from corresponding decays involving charged kaons.