Related papers: Low-mass scalar production in $\gamma \gamma$ scat…
We present for the first time a determination of the energy dependence of the isoscalar $\pi\pi$ elastic scattering phase-shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed…
We report observation of a narrow peak structure at ~1.54 GeV with a Gaussian width sigma=6 MeV in the missing of K_s in the reaction gamma+p = pK_sK_L. The observed structure may be due to the interference between a strange (or…
We demonstrate that the aperture mass as a measure for cosmic shear closely approximates (to better than ~5%) the scaled and shifted power spectrum of the projected mass density. This cosmological weak-lensing information can thus be used…
In this paper, we reanalyze the $I=0$ scalar channel with the improved Monte-Carlo based QCD sum rules, which combines the rigorous H\"older-inequality-determined sum rule window and a two Breit-Wigner type resonances parametrization for…
Our method of analysis, which led to existence of sigma and kappa mesons, is reviewed and examined from a viewpoint of general S-matrix. It is shown that the method is consistent with the constraints from chiral symmetry and unitarity.…
We analyze the scattering properties of a periodic one-dimensional system at criticality represented by the so-called power-law banded random matrix model at the metal insulator transition. We focus on the scaling of Wigner delay times…
Measurements of $\gamma p \rightarrow K^{+} \Lambda$ and $\gamma p \rightarrow K^{+} \Sigma^0$ cross-sections have been obtained with the photon tagging facility and the Crystal Ball calorimeter at MAMI-C. The measurement uses a novel $K^+$…
We present the first lattice QCD study of coupled isoscalar $\pi\pi,K\overline{K},\eta\eta$ $S$- and $D$-wave scattering extracted from discrete finite-volume spectra computed on lattices which have a value of the quark mass corresponding…
We present a unified picture which studies simultaneously the gamma gamma-->pi^+ pi^-, pi^0 pi^0, K^+ K^-, K^0 bar{K}^0, pi^0 eta reactions up to about sqrt(s)=1.4 GeV reproducing the experimental cross sections. The present work implements…
The coupled eta N, pi N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to pi N -> pi N, pi N -> eta N and gamma N -> eta N data in an energy range of about 100MeV each side of the…
We employ two simple and robust results to constrain the mixing matrix of the isosinglet scalar mesons $f_0(1710)$, $f_0(1500)$, $f_0(1370)$: one is the approximate SU(3) symmetry empirically observed in the scalar sector above 1 GeV and…
The lowest-lying resonance in the QCD spectrum is the $0^{++}$ isoscalar $\sigma$ meson, also known as the $f_0(500)$. We augment SU(2) chiral perturbation theory ($\chi$PT) by including the $\sigma$ meson as an additional explicit degree…
We calculate low-energy meson decay processes and pion-pion scattering lengths in a two-flavour linear sigma model with global chiral symmetry, exploring the scenario in which the scalar mesons $f_0$(600) and $a_0$(980) are assumed to be…
In the present talk, we report a recent investigation on photoproduction of the $\gamma N \to f_0(500)N$ within a framework of the effective Lagrangian. We include the nucleon resonances with pin $1/2$ in the $s$ channel. The coupling…
We propose a method to assess the quality of geometrical scaling in Deep Inelastic Scattering and apply it to the combined HERA data on $\gamma^{\ast}p$ cross-section. Using two different approaches based on Bjorken $x$ binning and binning…
In this work we present the analysis of the energy spectrum from a recent two-flavor ($N_f=2$) lattice QCD calculation for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The lattice simulation was performed for…
The production of $D_s^-$ relative to $D_s^+$ as a function of $x_F $ with 600 GeV/c $\Sigma^-$ beam is measured in the interval $0.15 < x_F < 0.7$ by the SELEX (E781) experiment at Fermilab. The integrated charge asymmetries with 600 GeV/c…
Inverse Compton Scattering at shallow angles can be used to tune the spectrum and increase the brightness of the emitted radiation. Here, we report on the demonstration of emission of visible light by a 4.7 MeV $e$-beam crossing a 780 nm…
The problem of scalar mesons still remains a challenging puzzle, for which we do not even know which are the right pieces to set up. The proliferation of resonances (some of them are very broad and appear on top of hadronic thresholds) and…
The s-wave kaon-antikaon ($K \bar{K}$) elastic scattering length is investigated by lattice simulation using pion masses $m_\pi = 330 - 466$ MeV. Through moving wall sources without gauge fixing, we calculate $K \bar{K}$ four-point…