相关论文: Mass and width of the $\Delta(1232)$ resonance usi…

A new unitarization approach incorporated with chiral symmetry is established and applied to study the $\pi K$ elastic scatterings. We demonstrate that the $\kappa$ resonance exists, if the scattering length parameter in the I=1/2, J=0…

The rigorous quantum mechanical definition of a resonance requires determining the pole position in the second Riemann sheet of the analytically continued partial wave scattering amplitude in the complex Mandelstam s-variable plane. For…

We present results of a high statistics study (O(2000) configurations) of the quark masses in the MS-bar scheme from Lattice QCD in the quenched approximation at beta=6.0, beta=6.2 and beta=6.4 using both the Wilson and the tree-level…

A light-cone QCD-inspired model, with the mass squared operator consisting of a harmonic oscillator potential as confinement and a Dirac-delta interaction, is used to study the S-wave meson spectra. The two parameters of the harmonic…

Chiral extrapolation of the $X(3872)$ binding energy is investigated using the modified Weinberg formulation of chiral effective field theory for the $D \bar{D}^*$ scattering. Given its explicit renormalisability, this approach is…

We show the results for the scattering poles associated to the rho, f0, a0, K*, sigma and kappa resonances in meson-meson scattering. Our amplitudes are obtained from the complete one-loop meson-meson scattering amplitudes from Chiral…

We investigate the widths of the recently observed charmonium like resonances X(3872), Z(4430) and Z_2(4250) using QCD sum rules. Extending previous analyses regarding these states as diquark-antiquark states or molecules of D mesons, we…

We review chiral symmetry breaking at the BCS level, in the framework of chiral invariant quark models and in the Schwinger-Dyson formalism. We revisit the pi mass problem beyond the BCS level. We show a theorem on the masses, on the widths…

We study the unitarized meson-baryon scattering amplitude at leading order in the strangeness $S=-1$ sector using time-ordered perturbation theory for a manifestly Lorentz-invariant formulation of chiral effective field theory. By solving…

We report a partial-wave analysis of new data on the double-polarization variable $E$ for the reactions $\gamma p\to \pi^+ n$ and $\gamma p\to \pi^0 p$ and of further data published earlier. The analysis within the Bonn-Gatchina (BnGa)…

Finite-range regularised (FRR) chiral effective field theory is presented in the context of approximation schemes ubiquitous in modern lattice QCD calculations. Using FRR techniques, the power-counting regime (PCR) of chiral perturbation…

We perform a non-perturbative chiral study of the masses of the lightest pseudoscalar mesons. In the calculation of the self-energies we employ the S-wave meson-meson amplitudes taken from Unitary Chiral Perturbation Theory (UCHPT) that…

I discuss the problem of constructing an effective low-energy theory in the vicinity of a resonance or a bound state. The focus is on the example of the $\Delta(1232)$, the lightest resonance in the nucleon sector. Recent developments of…

The perturbative result for the quark-mass conversion factor between the $\overline{\mathrm{MS}}$ and regularization-independent symmetric-momentum subtraction scheme (RI/SMOM) away from the chiral limit, i.e. at non-zero quark masses…

We investigate the role of the delta isobar in the reaction $\pi d\to \pi d$ at threshold in chiral effective field theory. We discuss the corresponding power counting and argue that this calculation completes the evaluation of diagrams up…

We apply the $\delta$-expansion to the Gross-Neveu model in the large $N$ limit with Wilson fermion and investigate dynamical mass generation from inverse-mass expansion. The dimensionless mass $M$ defined via the effective potential is…

We review our recent study of the pion mass dependence of the rho and sigma resonances, generated from one-loop SU(2) Chiral Perturbation Theory (ChPT) with the Inverse Amplitude Method (IAM). In order to properly account for the Adler zero…

I obtain the complex pole squared mass of the Z boson at full two-loop order in the Standard Model in the pure MS-bar renormalization scheme. The input parameters are the running gauge couplings, the top-quark Yukawa coupling, the Higgs…

We consider the model of a massless charged scalar field, in (2+1) dimensions, with a self interaction of the form $lambda (\phi^* \phi)^3$ and interacting with a Chern Simons field. We calculate the renormalization group $\beta$ functions…

We present a determination of the pion-nucleon sigma-term based on a novel analysis of the $\pi N$ scattering amplitude in Lorentz covariant baryon chiral perturbation theory renormalized in the extended-on-mass-shell scheme. This…