Using a theoretical framework based on the next-to-leading order QCD-improved effective Hamiltonian and a factorization Ansatz for the hadronic matrix elements of the four-quark operators, we reassess branching fractions in two-body non-leptonic decays B → P P, P V, V V , involving the lowest lying light pseudoscalar (P) and vector (V) mesons in the standard model. We work out the parametric dependence of the decay rates making use of the currently available information on the weak mixing matrix elements, form factors, decay constants and quark masses. Using the sensitivity of the decay rates on the effective number of colors, N c , as a criterion of theoretical predictivity, we classify all the current-current (tree) and penguin transitions in five different classes. The recently measured charmless two-body B → P P decays (

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Charmless non-leptonic B s decays to P P , P V and V V final states in the pQCD approach AbstractWe calculate the CP-averaged branching ratios and CP-violating asymmetries of a number of two-body charmless hadronic decays B 0 s → P P, P V, V V in the perturbative QCD (pQCD) approach to leading order in α s (here P and V denote light pseudo-scalar and vector mesons, respectively). The mixinginduced CP violation parameters are also calculated for these decays. We also predict the polarization fractions of B s → V V decays and find that the transverse polarizations are enhanced in some penguin dominated decays such as B 0 s → K * K * , K * ρ. Some of the predictions worked out here can already be confronted with the recently available data from the CDF collaboration on the branching ratios for the

We perform a number of improvements to the previous AKK extraction of fragmentation functions for π ± , K ± , p/p, K 0 S and Λ/Λ particles at next-to-leading order. Inclusive hadron production measurements from pp(p) reactions at BRAHMS, CDF, PHENIX and STAR are added to the data sample. We use the charge-sign asymmetry of the produced hadrons in pp reactions to constrain the valence quark fragmentations. Data from e + e − reactions in regions of smaller x and lower √ s are added. Hadron mass effects are treated for all observables and, for each particle, the hadron mass used for the description of the e + e − reaction is fitted. The baryons' fitted masses are found to be only around 1% above their true masses, while the values of the mesons' fitted masses have the correct order of magnitude. Large x resummation is applied in the coefficient functions of the e + e − reactions, and also in the evolution of the fragmentation functions, which in most cases results in a significant reduction of the minimized χ 2 . To further exploit the data, all published normalization errors are incorporated via a correlation matrix.

We present new sets of fragmentation functions for charged pions and kaons, both at leading and next-to-leading order. They are fitted to data on inclusive charged-hadron production in e+eannihilation taken by the TPC Collaboration at SLAC PEP (fi = 29 GeV) and to similar data by ALEPH at CERN LEP, who discriminated between events with charm, bottom, and light-flavor fragmentation in their charged-hadron sample. In contrast with our previous analysis, where we only distinguished between valence-quark, sea-quark, and gluon fragmentation, we are now able to treat all partons independently and to properly incorporate the charm and bottom thresholds. Because of the sizable energy gap between PEP and LEP, we are sensitive to the scaling violation in the fragmentation process, which allows us to extract a value for the asymptotic scale parameter of QCD, A. Recent data on inclusive charged-hadron production in tagged three-jet events by OPAL and similar data for longitudinal electron polarization by ALEPH allow us to pin down the gluon fragmentation functions. Our new fragmentation functions lead to an excellent description of a multitude of other e+e-data on inclusive charged-hadron production, ranging from fi = 5.2 GeV to LEP energy. In addition, they agree nicely with the transverse-momentum spectra of single charged hadrons measured by H1 and ZEUS in photoproduction at the DESY ep collider HERA, which represents a nontrivial check of the factorization theorem of the QCD-improved parton model. In this comparison, we also find first evidence for the interplay between the direct-and resolvedphoton mechanisms and for the existence of a gluon density inside the photon.PACS number(s): 13.65.+i, 13.60.Le, 13.87.Fh, 14.40.Aq LO FF's for ( T + + n-)