We present preliminary results on three SLD analyses: the gluon energy spectrum in 3-jet bb̄g events, the rate of g → bb̄, and the b fragmentation function in Z decays. The gluon energy spectrum, measured over the full kinematic range, is compared with perturbative QCD predictions. We set new 95% C.L. limits on the anomalous chromomagnetic coupling of the b quark: −0.09 < κ < 0.06. gbb̄ is measure...

Tremendous progress has been made experimentally in the hadron spectrum containing heavy quarks last two decades. It is surprising that many resonant structures are around thresholds of a pair hadrons. There should be threshold cusp at any $S$-wave threshold. By constructing nonrelativistic effective field theory with open channels, we discuss generalities behavior, and offer an explanation abu...

We study charmonium production in hadron-nucleus collisions through the intermediate next-to-leading Fock space component |(c¯ c) 8 g, formed by a colour octet c¯ c pair and a gluon. We estimate the size of this state and show that its interaction with nucleons accounts for the observed charmonium suppression in nuclear interactions.

Theoretical aspects of VMD and related approaches to real photon-hadron interaction are discussed. The work relies on special relativity, properties of linearly polarized photons, angular momentum conservation and relevant experiments. It is explained why VMD and similar approaches should not be regarded as part of a theory but, at most, as phenomenological models. A further experiment pertaini...

We report on our recent work on electroweak corrections to tt̄ production at hadron colliders. Specifically, we discuss the weak-interaction contributions to the top quark transverse momentum and tt̄ invariant mass distributions and an induced parity-violating top-spin asymmetry. PACS number(s): 12.15.Lk, 12.38.Bx, 13.88.+e, 14.65.Ha

We show that for hadronic transverse energy ET in hadron-hadron collisions, the classic Collins-Soper-Sterman (CSS) argument for the cancellation of Glauber gluons breaks down at the level of two Glauber gluons exchanged between the spectators. Through an argument that relates the diagrams with these Glauber gluons to events containing additional soft scatterings, we suggest that this failure o...

New results of NA61/SHINE on determination of charged hadron yields in proton-carbon interactions are presented. They aim to improve predictions of the neutrino flux in the T2K experiment. The data were recorded using a secondary-proton beam of 31 GeV/c momentum from CERN SPS which impinges on a graphite target. To determine the inclusive production cross section for charged pions, kaons and pr...