We study the shift in the Υ mass due to a non-zero charm quark mass. This shift affects the value of the MS b-quark mass extracted from the Υ system by about −20 MeV, due to an incomplete cancellation of terms that are nonanalytic in the charm quark mass. The precise size of the shift depends on unknown higher order corrections, and might have a considerable uncertainty if they are large. Types...

I review recent progress on bottom-quark fragmentation in e + e − annihilation, top-quark decay and H → b ¯ b processes. I discuss the implementation of collinear and soft resummation, and the inclusion of non-perturbative information taken from LEP and SLD data. Heavy-quark physics is currently one of the major fields of investigation in experimental and theoretical particle physics. In order ...

A model independent analysis has been performed on the LEP and SLD data on Z decays. Using only very weak theoretical assumptions, the effective vector and axial-vector couplings of leptons, c quarks and b quarks have been extracted. Although the lepton and c quark couplings agree well with Standard Model predictions, those of the b quark show deviations of more than three standard deviations. ...

We investigate the variation in the MMHT2014 PDFs when we allow the heavy-quark masses [Formula: see text] and [Formula: see text] to vary away from their default values. We make PDF sets available in steps of [Formula: see text] and [Formula: see text], and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functio...

We present the first study of treating b, c, and s quarks as Dirac fermions in lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with single-plaquette action at β = 7.2 on the 323 × 60 lattice, we compute point-to-point quark propagators for 33 quark masses in the range 0.01 ≤ mqa ≤ 0.85, and measure the time-correlation function of (pseudo-)scalar, (pseudo-)vector,...

Because of the fractional baryon number of quarks, baryon and antibaryon number fluctuations in the quark-gluon plasma is less than those in the hadronic matter, making them plausible signatures for the quark-gluon plasma expected to be formed in relativistic heavy ion collisions. To illustrate this possibility, we have introduced a kinetic model that takes into account both production and anni...

It has been known that the Flavor Changing process in down quark sector is sensitive to the mass difference among up-type quark in the standard model (SM). GIM mechanism tells us that the FCNC in one-loop level of SM vanishes when up type quarks are degenerate. In the real world , there is large mass gap among up quark sector (Mu ≪ Mc ≪ Mt). Then the Flavor Changing Process in down quark sector...

A summary of some recent studies in jet physics is given. Topics include leading particle production in light flavor events in e + e − annihilations, an analytical treatment of gluon and quark jets at the next-to-next-to-next-to-leading order (3NLO), and various studies performed at LEP and HERA involving separated gluon and quark jets. 1 Leading particle production in separated light quark eve...

We present results for the mass of the b quark in the M S scheme obtained by calculating the binding energy of the B meson in the static limit. The self energy of a static quark, E ∞ 0 needed for this purpose, is now known to O(α 3) in the quenched approximation. We find a preliminary value of m b (m b) = 4.34(7) GeV at n f = 0. The error is dominated by the remaining uncertainty in E ∞ 0. In a...

5 Quark-hadron duality 51 6 Conclusion 55 ii 0.1 Preface This Thesis is a review of the inclusive decays of heavy hadron. It is based on the author's study of two issues which are important in the description of the inclusive beauty decays given by the heavy quark expansion. • Evaluation of the expectation values of the four-quark operators in the heavy quark expansion, • Study on the validity ...