Azimuthal correlation between the (p ℓ , p X b) and (p ℓ , P t) planes in the semileptonic rest frame decay of a polarized top quark: An O(α s) effect Abstract The azimuthal correlation between the planes formed by the vectors (p ℓ , p X b) and (p ℓ , P t) in the semileptonic rest frame decay of a polarized top quark t(↑) → X b + l + + ν ℓ belongs to a class of polarization observables involvin...

the parton model. Figure 2: Peterson's fragmentation function and our reened form for describing decay processes. The solid line denotes our reened function and the dashed line Peterson's original function. Figure 3: (a) The photon energy spectrum of B ! X s process with Peter-son's function (dashed line) and with our reened function (solid line). (b) The electron energy spectrum of B ! e X u p...

An overview of recent results from LEP concerning the hadronisation process is presented. Emphasis is placed on the b-quark. The first presented analysis is the measurement of the b-quark fragmentation function. It includes a new, hadronic-model independent method to extract the x-dependence of the non-perturbative QCD component from the measured fragmentation function. This is followed by the ...

I consider a model for heavy meson decays based on an effective quark-meson Lagrangian. The model is constrained by the known symmetries of QCD in the mQ → ∞ limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the leptonic B and B∗∗ decay constants; the Isgur-Wise...

We present determinations of the -meson decay constant f(B) and f(B)(s)/f(B) using the MILC Collaboration unquenched gauge configurations, which include three flavors of light sea quarks. The mass of one of the sea quarks is kept around the strange quark mass, and we explore a range in masses for the two lighter sea quarks down to m(s)/8. The heavy quark is simulated using nonrelativistic QCD, ...

It is shown, that the presently accepted value for b-quark mass can be obtained from the requirement of the exact b − τ unification in the both non-SUSY and SUSY non-chiral extended GUTs. Introduction. In due time the minimal SU(5) grand unification proposal [1] had ignited interest to the Grand Unified Theory (GUT) business by the calculation of the unification scale M GUT and mixing angle sin...

Using a combination of the operator product and heavy quark expansions, we resum the leading nonperturbative contributions to the inclusive photon spectrum in B → Xs γ decays. The shape of the spectrum is determined by a universal structure function, which describes the distribution of the light-cone momentum of the b-quark inside the B-meson. The moments of this function are proportional to fo...

In the fragmentation of a heavy quark into a heavy meson whose light degrees of freedom have angular momentum 3/2, all the helicity probabilities are completely determined in the heavy quark limit up to a single probability w 3/2. We point out that this probability depends on the longitudinal momentum fraction z of the meson and on its transverse momentum p ⊥ relative to the jet axis. We calcul...

Heavy-quark spin symmetry (HQSS) implies that in the direct decay of a heavy quarkonium with $S$, only lower lying quarkonia same $S$ can be produced. However, this selection rule, expected to work very well $b$-quark sector, overcome if multiquark intermediate states are involved chain, allowing for transitions final-state different ${S}^{\ensuremath{'}}$. In particular, measured decays $\math...

We present lattice results for the spectrum of mesons containing one heavy quark and of baryons containing one or two heavy quarks. The calculation is done in the quenched approximation using the NRQCD formalism for the heavy quark. We analyze the dependence of the mass splittings on both the heavy and the light quark masses. Meson P -state fine structure and baryon hyperfine splittings are res...