After updating the determination of the combination of Kobayashi-Maskawa elements Im V ∗ tsVtd according to a new estimate of the parameter B̂K , we study the CP -violating ratio ε/ε by means of hadronic matrix elements computed to O(p4) in the chiral expansion and NLO Wilson coefficients. It is the first time that this order in chiral perturbation theory is included in the analysis. The most im...

In left-right models the gluonic penguin contribution to b → ss̄s transition is enhanced by mt/mb due to the presence of (V+A) currents and by the larger values of loop functions than in the Standard Model. Together those may completely overcome the suppression due to small left-right mixing angle ξ <∼ 0.013. Two independent new phases in the B → φKS decay amplitude appearing in a large class of...

A systematic approach to long-distance effects in exclusive radiative weak B decays is presented, based on a combination of the heavy quark limit with perturbative QCD. The dominant long-distance effects, connected with weak annihilation and W-exchange topologies, can be computed in a model-independent way using experimental data on B radiative leptonic decays. Nonfactorizable corrections vanis...

The standard model contribution to ǫ/ǫ of the magneticand electric-dipole penguin operators Q11 = gs 16π ms s̄ σμνt G a (1− γ5) d and Q12 = eQd 16π ms s̄ σμνF μν(1− γ5) d is discussed. While the electromagnetic penguin Q12 seems to have a vanishingly small matrix element, we find that the gluonic dipole operator Q11 may give a contribution to ǫ/ǫ comparable to that of other operators so far consi...

We systematically analyse the gluonic penguin-induced charmless decays B → KXφ(KX denotes the meson state sq (q = u or d) ), in the standard model and the two-Higgsdoublet model. These processes, being induced at one-loop level, are of great importance in measuring the virtual top quark effect in the standard model, and also in searching for the non-standard signals in the low energy region. It...

I discuss the role of the ∆I = 1/2 selection rule in K → ππ decays for the theoretical calculations of ε/ε . Lacking reliable “first principle” calculations, phenomenological approaches may help in understanding correlations among different contributions and available experimental data. In particular, in the chiral quark model approach the same dynamics which underlies the ∆I = 1/2 selection ru...

We present the first study of the gluonic excitation in the three-quark (3Q) system in SU(3) lattice QCD with beta=5.8 and 16(3) x 32 at the quenched level. For the spatially fixed 3Q system, we measure the gluonic excited-state potential, which is responsible for the properties of hybrid baryons. The lowest gluonic-excitation energy in the 3Q system is found to be about 1 GeV in the hadronic s...

The possibility of η ′ having a gluonic admixture is still not excluded. In fact, the anomalous coupling of gluonic component of η ′ may play an important role towards understanding the unexpectedly large branching ratio for B → η ′ X s reported by CLEO. We point out that the η ′ gluonic component may be as large as 26 % by analysing the latest experimental data.