We analyze the double radiative B-meson decays Bs → γγ and Bd → γγ in QCD factorization based on the heavy-quark limit mb ≫ ΛQCD. We systematically discuss the various contributions to these exclusive processes. The dominant effect arises from the magnetic-moment type transition b → s(d)γ where an additional photon is emitted from the light quark (one-particle reducible diagram). The contributi...

The hadronic decays B → J/ψK(K∗) are interesting because experimentally they are the only color-suppressed modes which have been measured, and theoretically they are calculable by QCD factorization even the emitted meson J/ψ is heavy. We analyze the decay B → J/ψK within the framework of QCD factorization in the heavy quark limit. We show explicitly the scale and γ5-scheme independence of decay...

In this paper, we calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to exclusive processes $B_c^+\to \chi_{cJ}(h_c)\pi^+$ in framework of nonrelativistic QCD (NRQCD) factorization formalism. The results show that NLO markedly enhance branching ratios with $K$ factors about 2.5. combination study J/\psi\pi^+$, find NRQCD prediction for ratio fractions $\frac{\mat...

We discuss the structure of infrared singularities in on-shell QCD amplitudes with massive partons and present a general factorization formula in the limit of small parton masses. The factorization formula gives rise to an all-order exponentiation of both, the soft poles in dimensional regular-ization and the large collinear logarithms of the parton masses. Moreover, it provides a universal rel...

The QCD treatment of the photon structure is recalled. Emphasis is given to the recently derived momentum sum rule, and to the proper choice of the factorization scheme and/or boundary conditions for the evolution equations beyond the leading order. Parametrizations of the photon’s parton content are examined and compared. The small-x behaviour of the photon structure is briefly discussed. ∗ In...

Heavy quarkonium production at high transverse momentum ( p_T pT ) in hadronic collisions is explored the QCD factorization approach. We find that leading power 1/p_T display="inline">1/p</mml:mi...

We complete the investigation of loop corrections to hard spectator-scattering in exclusive B meson to light meson transitions by computing the short-distance coefficient (jet-function) from the hard-collinear scale. Adding together the two coefficients from matching QCD → SCET I → SCET II , we investigate the size of loop effects on the ratios of heavy-to-light meson form factors at large reco...