We show how the operator product expansion evaluated in the approximation of ignoring gluons leads to the covariant formulation of the quark parton model. We discuss the connection with other formulations and show how the free quark model prediction, g2 = 0, changes smoothly into the Wandzura-Wilczek (WW) relation for quark masses small relative to the nucleon mass. Previous contradictory parto...

We compute the three-loop relation between the pole and the minimally subtracted quark mass allowing for virtual effects from a second massive quark. We also consider the analogue effects for the on-shell wave function renormalization constant. PACS numbers: 12.38.Bx 12.38.-t 14.65.Dw 14.65.Fy

Classification using high-dimensional features arises frequently in many contemporary statistical studies such as tumor classification using microarray or other high-throughput data. The impact of dimensionality on classifications is largely poorly understood. In a seminal paper, Bickel and Levina (2004) show that the Fisher discriminant performs poorly due to diverging spectra and they propose...

Top quark events in hadron collisions often contain additional hadronic jets from gluon bremsstrahlung off the quarks and gluons in the hard subprocesses. Such extra jets must be taken into account in attempts to reconstruct the momentum of the top quark from those of its decay products. We have performed a complete calculation of gluon radiation in top production and decay at the Fermilab Teva...

In a model proposed in 2012, all flavor mixing has a single source and is governed by a single “master matrix.” This model was shown to give several predictions for quark and lepton masses and mixing angles and for mixing angles within SU(5) multiplets that are observable in proton decay. Here it is shown that the same master matrix controls the flavor-changing processes mediated by a singlet s...

Present data do not rule out the light neutral Higgs particle h or A with mass below 40–50 GeV in the framework of the general 2HDM (”Model II”). The recent limits from LEP I on the parameters of the model, based on the Bjorken process Z → Zh, Higgs pair production Z → Ah and the Yukawa process Z → f f̄A (f = b quark or τ lepton) are presented. Including limits on Higgs bosons masses from LEP I ...

We argue that there exists simple relation between the quark and lepton mixings which supports the idea of grand unification and probes the underlying robust bimaximal fermion mixing structure of still unknown flavor physics. In this framework the quark mixing matrix is a parameter matrix describing the deviation of neutrino mixing from exactly bi-maximal, predicting θsol+θC = π/4, where θC is ...

The perturbative quark–mass corrections to the τ hadronic width are analysed to O(αsm 2 q), using the presently available theoretical information. The behaviour of the perturbative series is investigated in order to assess the associated uncertainties. The implications for the determination of the strange quark mass from τ decay data are discussed.

We discuss a model for heavy mesons where the light quark (u or d) moves in the colour electric field from a heavy quark (c or b) placed in the center of the bag. We calculate energy spectra for pionic and photonic transitions from excited states. The transition amplitudes and the branching ratios between electromagnetic and pionic transitions compares favorable with the limited amount of known...