Related papers: Hard spectator interactions in B to pi pi at order…
We present a new calculation of long-distance contributions to the K --> pi pi amplitudes using the 1/N_c expansion within the framework of chiral perturbation theory. Along these lines we compute the chiral loop corrections to the…
Multi-jet rates at hadron colliders provide a unique possibility for probing Quantum Chromodynamics (QCD), the theory of strong interactions. By comparing theory predictions with collider data, one can directly test perturbative QCD,…
By employing the perturbative QCD (PQCD) factorization approach, we calculated the branching ratios, CP-violating asymmetries, the longitudinal and transverse polarization fractions and other physical observables of the thirteen charmless…
Light-cone distribution amplitudes (LCDAs) frequently arise in factorization theorems involving light and heavy mesons. The QCD LCDA for heavy mesons includes short-distance physics at energy scales of the heavy-quark mass. In this paper we…
We show that the QCD factorization approach for $B$-meson decays to charmless hadronic two-body final states can be extended to include electromagnetic corrections. The presence of electrically charged final-state particles complicates the…
We investigate to what extent the experimental information on $B \to \pi\pi$ branching fractions and CP asymmetries can be used to better understand the QCD dynamics in these decays. For this purpose we decompose the independent isospin…
In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and B-> D*…
High-order perturbative calculations for thermodynamic quantities in QCD are complicated by the physics of dynamical screening that affects the soft, long-wavelength modes of the system. Here, we provide details for the evaluation of this…
We propose a formalism to extract the $\gamma\pi\to\pi\pi$ chiral anomaly $F_{3\pi}$ from calculations in lattice QCD performed at larger-than-physical pion masses. To this end, we start from a dispersive representation of the…
The low-energy $\pi\pi$ amplitude is computed explicitly to two-loop accuracy in the chiral expansion. It depends only on six independent (combinations of) low-energy constants which are not fixed by chiral symmetry. Four of these constants…
We demonstrate the lattice QCD calculation of the long distance contribution to $\epsilon_K$. Due to the singular, short-distance structure of $\epsilon_K$, we must perform a short-distance subtraction and introduce a corresponding…
We compute NNLO (${\cal O}(\alpha_s^2)$) corrections to the hard-scattering kernels entering the QCD factorization formula for $B\to V\gamma$ decays, where $V$ is a light vector meson. We give complete NNLO results for the dipole operators…
Soft-collinear effective theory is generalized to include soft massless quarks in addition to collinear fields. This extension is necessary for the treatment of interactions with the soft spectator quark in a heavy meson. The power counting…
We present leading logarithmic QCD corrections to the decay B_s --> \gamma\gamma in the Standard Model. Further, the form factor F_{1}(0) of B_s --> \phi\gamma is calculated in the framework of QCD sum rules and found to be in agreement…
The eigenvalue spectrum $\rho(\lambda)$ of the Dirac operator is numerically calculated in lattice QCD with 2+1 flavors of dynamical domain-wall fermions. In the high-energy regime, the discretization effects become significant. We subtract…
In this work, we suggest that hard-pion chiral perturbation theory may be applicable to the real parts of nonleptonic B^{+} to D^{0}P^{+} and B^{+} to Dbar^{0}P^{+} (P=K,pi) decay amplitudes. These amplitudes play an important role in the…
To describe the weak three-body B decays into pi+ pi- K, we recently derived amplitudes based on two-body QCD factorization followed by pi+ pi- final state interactions in isoscalar S- and isovector P-waves. We study here the sensitivity of…
I present generalized formulas for approximate corrections to QCD hard-scattering cross sections through second order in the perturbative expansion. The approximate results are based on recent two-loop calculations for soft and collinear…
The B* B pi coupling is a fundamental parameter of chiral effective Lagrangian with heavy-light mesons and can constrain the B->pi l nu form factor in the soft pion limit which will be useful for precise determination of |Vub|. We compute…
Considering, as a limit case, an approximately flat pion distribution amplitude, which is determined from the hardest, in momentum space, solution of the Bethe-Salpeter equation for the pion wave function, we compute the pion transition…