Related papers: Heavy Quark Distribution Function in QCD and the A…
The evaluation of partonic distributions presents a challenge for QCD, and in particular for its Euclidean lattice realization. Recently, objects called quasi-distributions (which become standard distributions in a limit of the longitudinal…
We present a new QCD sum rule with high sensitivity to the continuum regions of charm and bottom quark pair production. Combining this sum rule with existing ones yields very stable results for the MS-bar quark masses, m_c(m_c) and…
We derive a new parton-like formula, which establishes a simple connection between the electroweak decay rate $\Gamma (\bar B \to X_s\gamma$) and the rate of a free b-quark decay. The main features of our approach are the treatment of the…
We extend our previous study of the SU(3) gauge theory with N_f=2 flavors of fermions in the sextet representation of color. Our tool is the Schroedinger functional method. By changing the lattice action, we push the bulk transition of the…
The question of the anomalies in the effective theory of heavy quarks is investigated at two different levels. Firstly, it is shown that none of the symmetries of this effective theory contains an anomaly. The existence of a new `$ \gamma _…
The chirally unbroken and the superconducting 2SC and CFL phases are investigated in the chiral limit within a Dyson-Schwinger approach for the quark propagator in QCD. The hierarchy of Green's functions is truncated such that at vanishing…
We present an analytic formula for the $O(\alpha_s)$ corrections to the decay $t\to H^+b$ for nonzero $m_H$ and $m_b$. The Equivalence Theorem is used to relate these corrections to those for the process $t\to W^+b$. Contrary to previously…
We investigate the heavy quark mass effects on the parton distribution functions in the unpolarized virtual photon up to the next-to-leading order in QCD. Our formalism is based on the QCD-improved parton model described by the DGLAP…
Recent experiments with ultracold fermionic atoms in optical lattices have provided a tuneable and clean realization of the attractive Hubbard model (AHM). In view of this, several physical properties may be thoroughly studied across the…
Factorization scheme analysis of $F_2^{\gamma}(x,Q^2)$ in the next-to-leading order QCD is revisited. It is emphasized that the presence of the inhomogeneous term in the evolution equations for quark distribution functions of the photon…
We consider the decay of a heavy flavour into an inclusive hadronic state X of invariant mass m_X small with respect to its energy E_X, m_X << E_X. The electron spectrum and the hadronic mass distribution in semileptonic b -> u decays, or…
The radiative decays of $D^*$, $B^*$, and other excited heavy mesons are analyzed in a relativistic quark model for the light degrees of freedom and in the limit of heavy quark spin-flavor symmetry. The analysis of strong decays carried out…
We calculate the Lamb, fine and hyperfine shifts in $b\bar b$ with $n=2$, $l=0,1$. Radiative corrections as well as leading nonperturbative corrections (known to be due to the gluon condensate) are taken into account. The calculation is…
Recent progress on QCD sum rule determinations of the light and heavy quark masses is reported. In the light quark sector a major breakthrough has been made recently in connection with the historical systematic uncertainties due to a lack…
We investigate transition form factors between non-relativistic QCD bound states at large recoil energy. Assuming the decaying quark to be much heavier than its decay product, the relativistic dynamics can be treated according to the…
Heavy quarks placed within a hot QCD medium undergo Brownian motion, characterized by specific transport coefficients. Their determination can be simplified by expanding them in $T/M$, where $T$ is the temperature and $M$ is a heavy quark…
Nonmesonic decays of $\Lambda$ in nuclear medium and light hypernuclei are studied by using the $\Lambda N \to NN$ weak transition potential derived from the meson exchange mechanism and the direct quark mechanism. The long range part of…
We compute long distance effects on the photon energy spectrum in inclusive radiative decays of $B$ mesons using light-cone expansion and heavy quark effective theory. We show that for sufficiently high photon energy the leading…
We study the spectral properties of a chiral random banded matrix (chRBM) with elements decaying as a power-law ${{\cal H}_{ij}}\sim |i-j|^{-\alpha}$. This model is equivalent to a chiral 1D Anderson Hamiltonian with long range power-law…
We investigate the influence of dynamical charm quarks on observables that depend explicitly on the charm quark fields, like the pseudo-scalar and vector masses $m_{\eta_c}$ and $m_{J/\psi}$, the hyperfine splitting…