L. Leśniak

Separation of S-wave pseudoscalar and pseudovector amplitudes in π−P↑ → π+π−n reaction on polarized target

A new analysis of S-wave production amplitudes for the reaction π−p↑ → π+π−n on a transversely polarized target is performed. It is based on the results obtained by the CERN-Cracow-Munich collaboration in the ππ energy range from 600 MeV to 1600 MeV at 17.2 GeV/c π− momentum. Energy-independent separation of the S-wave pseudoscalar amplitude (π exchange) from the pseudovector amplitude (a1 exchange) is carried out using assumptions much weaker than those in all previous analyses. We show that, especially around 1000 MeV and around 1500 MeV, the a1 exchange amplitude cannot be neglected. The scalarisoscalar ππ phase shifts are calculated using fairly weak assumptions. Below the KK̅ threshold we find two solutions for the π — π phase shifts, for which the phases increase slower with the effective π — π mass than the P-wave phases. Both solutions are consistent with a broad f0(500) but only one is similar to the well-known “down” solution. We find also the third solution (with a somewhat puzzling behavior of inelasticity) which exhibits a narrow f0(750) claimed by Svec. All the solutions undergo a rapid change at the KK̅ threshold. Above 1420 MeV the phase shifts increase with energy faster than those obtained without the polarized-target data. This phase behavior as well as an increase of the modulus of the a1-exchange amplitude can be due to the presence of the f0(1500).

Three channel model of meson-meson scattering and scalar meson spectroscopy

Abstract New solutions on the scalar-isoscalar ππ phase shifts are analysed together with previous K K results using a separable potential model of three coupled channels (ππ, K K and an effective 2π2π system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the π−p↑ → π+π−n reaction on a polarized target. A relatively narrow (90–180 MeV) scalar resonance f0(1400–1460) is found, in contrast to a much broader (Γ ≈ 500 MeV) state emerging from the analysis of previous unpolarized target data.

Long-distance effects and final state interactions in B→ππK and B→KK¯K decays

Abstract B decays into π π K and K K ¯ K , where the ππ and K ¯ K pairs interact in isospin zero S-wave, are studied in the ππ effective mass range from threshold to 1.2 GeV. The interplay of strong and weak decay amplitudes is analyzed using an unitary ππ and K K ¯ coupled channel model. Final state interactions are described in terms of four scalar form factors constrained by unitarity and chiral perturbation theory. Branching ratios for the B → f 0 ( 980 ) K decay, calculated in the factorization approximation with some QCD corrections, are too low as compared to recent data. In order to improve agreement with experiment, we introduce long-distance contributions called charming penguins. Effective mass distributions, branching ratios and asymmetries are compared with the existing data from BaBar and Belle Collaborations. A particularly large negative asymmetry in charged B decays is predicted for one set of the charming penguin amplitudes.

Final state interactions in B±→K+K−K± decays

Charged B decays to three charged kaons are analysed in the framework of the QCD factorization approach. The strong final state K+K-interactions are described using the kaon scalar and vector form factors. The scalar non-strange and strange form factors at low K+K- effective masses are constrained by chiral perturbation theory and satisfy the two-body unitarity conditions. The latter stem from the properties of the meson-meson amplitudes which describe all possible S-wave transitions between three coupled channels consisting of two kaons, two pions and four pions. The vector form factors are fitted to the data on the electromagnetic kaon interactions. The model results are compared with the Belle and BaBar data. Away from phi(1020) resonance, in the S-wave dominated K+K- mass spectra, a possibility for a large CP asymmetry is identified.

Coupled channel analysis of S -wave π π and K K ¯ photoproduction

We present a coupled channel partial wave analysis of nondiffractive S-wave pi+ pi- and K+ K- photoproduction focusing on the KK threshold. Final state interactions are included. We calculate total cross sections, angular and effective mass distributions in both pion-pion and kaon-antikaon channels. Our results indicate that these processes are experimentally measurable and valuable information on the f0(980) resonance structure can be obtained.

Dalitz-plot dependence of CP asymmetry in B±→K±K+K− decays

Abstract A large CP-violating asymmetry predicted recently in the framework of the QCD factorization model for the B ± → K ± K + K − decays in the range of the K + K − invariant masses above the ϕ ( 1020 ) resonance up to 1.4 GeV has been confirmed by the LHCb Collaboration. We discuss the emergence and size of this asymmetry in an extended model involving S- and P-waves together with the contribution from the D-wave f 2 ( 1270 ) resonance and compare our model with the experimental data of the LHCb and BABAR Collaborations.

Dalitz plot studies of D0 → KS0π+π− decays in a factorization approach

A quasi two-body QCD factorization is used to study the D 0 → K S 0 π + π − decays. The presently available high-statistics Dalitz plot data of this process measured by the Belle and BABAR Collaborations are analyzed together with the τ − → K S 0 π − ν τ decay data. The total experimental branching fraction is also included in the fits which show a very good overall agreement with the experimental Dalitz plot density distributions. The branching fractions of the dominant channels compare well with those of the isobar Belle or BABAR models. We show that the branching fractions corresponding to the annihilation amplitudes are significant.

Final State Strong Interaction Constraints on Weak {D^0 \to K^0_S \pi^+ \pi^-} Decay Amplitudes

Weak decay tree and annihilation-t-channel W-exchange amplitudes for the

Dalitz plot studies of D0 → KS0π+π− decays

{D^0 \to K^0_S \pi^+ \pi^-}