We study the prospects for probing the quark content of the photon using b tagging at high energy electron-photon colliders. We find that heavy quark tagging provides a sensitive and effective probe of the quark content of the photon. Using a 500 GeV ee NLC in electron-photon mode, the cross section for ebγ → eb can be measured to 10% with b tagging. This is sufficient to differentiate between ...

We develop an impact representation for the generalized distribution amplitude which describes the exclusive hadronization of a quark-antiquark pair to a pair of mesons. Experiments such as γγ → ππ and γN → ππN ′ are shown to probe the transverse size of the hadronization region of the quark antiquark pair that one can interpret as the transverse overlap of the two emerging mesons. An astonishi...

We discuss prospects for improving the q 2 extrapolation of the B → πlν form factors with model-independent constraints based on unitarity and heavy quark power-counting. As an illustration, we apply the method to preliminary results of calculations of the form factors, which we generated using the MILC gauge configurations and the Fermilab action for the heavy b-quark. Unitarity, the heavy qua...

Measurements of heavy quark production in electron–positron collisions are used to analyse the strong interactions between quarks and anti-quarks. A scaling behaviour is observed in distributions of the rapidity change of D, B, and B mesons. From these distributions information is obtained on the hadron formation time, effective quark masses, and the potential between quark–antiquark pairs. Pre...

Measurements of heavy quark production in electron–positron collisions are used to analyse the strong interactions between quarks and anti-quarks. A scaling behaviour is observed in distributions of the rapidity change of D, B, and B mesons. From these distributions information is obtained on the hadron formation time, effective quark masses, and the potential between quark–antiquark pairs. Pre...

We determine the constraints on the anomalous top-quark coupling associated with the flavor-changing neutral current vertex t̄cγ from the limits on the b-quark rare decay b → sγ and non-standard top-quark decays. Based on these constraints, we discuss the experimental observability of the rare decay mode t → cγ, both at the Fermilab Tevatron with a luminosity-upgrade and at the LHC.

We present a quenched calculation of the form factors of the semileptonic weak decay B → πl¯ ν with O(1/mQ) NRQCD heavy quark and Wilson light quark on a 16 3 × 32 lattice at β = 5.8. The form factors are evaluated at six heavy quark masses, in the range of mQ ∼ 1.5 − 8 GeV. 1/mQ dependence of matrix elements are investigated and compared with HQET predictions. We observe clear signal for the f...

We study soft-gluon radiation in top quark decay within the framework of perturbative fragmentation functions. We present results for the b-quark energy distribution, accounting for soft-gluon resummation to next-to-leading logarithmic accuracy in both the MS coefficient function and in the initial condition of the perturbative fragmentation function. The results show a remarkable improvement a...