Related papers: Regularization of a Light-Front Qqq Model
I describe some insight obtained from a lattice calculation on the possibility that the light scalar mesons are \qbar^2 q^2 states rather than \qbar q. First I review some general features of \qbar^2 q^2 states in QCD inspired quark models.…
The generalization of the effective action [1] of the quark--antiquark system in the confining vacuum is performed for the case of arbitrary quark masses. The interaction of quarks is described by the averaged Wilson loop for which we use…
We use complex Langevin simulations to study the QCD phase diagram with two light quark flavours. In this study, we use Wilson fermions with an intermediate pion mass of $\sim480\,$MeV. By studying thermodynamic quantities, in particular at…
We report on lattice QCD results for the thermodynamic equation of state of quark-gluon matter obtained with Nf=2 degenerate quark flavors. For the fermion field discretization we are using the Wilson-twisted mass prescription. Simulations…
We study the possibility that the light scalar mesons are (qbar qbar q q) states rather than (qbar q). We perform a lattice QCD calculation of pseudoscalar meson scattering amplitudes, ignoring quark loops and quark annihilation, and find…
Twisted mass lattice QCD (tmQCD), generalised to four Wilson quark flavours, can be used for the computation of some weak matrix elements related to $\Delta I=1/2$ transitions. Besides eliminating unphysical zero modes, tmQCD may alleviate…
This talk provides a brief summary of the status of lattice QCD calculations of the light quark masses and the kaon bag parameter B_K. Precise estimates of these four fundamental parameters of the standard model, i.e., m_u, m_d, m_s and the…
Stimulated by the observation of $\Lambda_c(2910)^+$ by the Belle Collaboration, the $S$-wave $qqq\bar{q}c~(q=u~\text{or}~d)$ pentaquark systems with $I$ = 0, $J^P$ = $\frac{1}{2}^-,~\frac{3}{2}^- and~\frac{5}{2}^-$ are investigated in the…
We study radiative decays of heavy $Q{\bar Q}$ states, both for $Q=c$ and $Q=b$, using an effective Lagrangian approach which exploits spin symmetry for such states. We use existing data on radiative quarkonium transitions to predict some…
Motivated by the recently constructed interpolation field for S$_{11}$(1535), we propose a new interpolating field for $\Lambda$(1405). Using this current, we calculate the mass of $\Lambda$(1405) based on the conventional QCD sum rule…
Masses of the p-wave excited heavy baryons have been calculated to the Lambda_{QCD}/m_Q order using QCD sum rule method within the framework of heavy quark effective theory. Numerical results for kinetic energy lambda_1 and chromo-magnetic…
This paper applies the analytic forms of a recent non-perturbative, manifestly gauge- and Lorentz-invariant description (of the exchange of all possible virtual gluons between quarks ($Q$) and/or anti-quarks ($\bar{Q}$) in a quenched,…
We scrutinize, improve some determinations of the masses and couplings of light scalar quarkonia ($\bar qq$ and four-quark states) and present new results for the $\pi^+\pi^-,K^+K^-,\dots$ molecules using QCD Laplace Sum Rule (LSR)…
Five-quark (5Q) picture of Lambda(1405) is studied using quenched lattice QCD with an exotic 5Q operator of N\bar{K} type. To discreminate mere N\bar{K} and \Sigma\pi scattering states, Hybrid Boundary Condition (HBC), a flavor-dependent…
We consider HQET including the first order correction in 1/m. A strategy for the computation of the b-quark mass is discussed. Only two quantities Phi_1/2 have to be considered in order to match QCD and HQET, since the spin-dependent…
We show how Loop Quantum Cosmology can be derived as an effective semiclassical description of Loop Quantum Gravity. Using the tools of QRLG, a gauge fixed version of LQG, we take the coherent states of the fundamental microscopic theory…
We present a lattice QCD determination of light quark masses with three sea-quark flavours ($N_f = 2+1$). Bare quark masses are known from PCAC relations in the framework of CLS lattice computations with a non-perturbatively improved…
The spin-averaged binding energy and the hyperfine mass splitting of heavy-light mesons are investigated within the constituent quark model as a function of the inverse heavy-quark mass. It is shown that the so-called heavy-quark kinetic…
We present results on the equation of state in QCD with two light quark flavors and a heavier strange quark. Calculations with improved staggered fermions have been performed on lattices with temporal extent Nt =4 and 6 on a line of…
QCD Laplace sum-rules are briefly reviewed and two sum-rule applications are presented. For scalar gluonium, upper bounds on the lightest state are obtained from ratios of Laplace sum-rules, and the role of instantons and the low-energy…