Related papers: Normalization discrepancies in photoproduction rea…
The paper presents a first time attempt on a combined fit of the $K^{-}p$ low-energy data and the $\pi\Sigma$ photoproduction mass spectra, performed without fixing the meson-baryon rescattering amplitudes to a specific $\pi\Sigma -…
There are now several experimental collaborations that have seen evidence for a narrow state in the mass spectrum of the ($nK^+$) system. Two of these experiments, from the LEPS collaboration in Japan and the CLAS collaboration in the USA,…
The high-precision differential cross-section data for the reaction $\gamma p \to K^{*+}\Lambda$ are reanalyzed within a Regge-inspired effective Lagrangian approach. The model adopts Regge phenomenology to constrain the $t$-channel…
The reaction $ep \to e'K^+\Lambda(1520)$ with $\Lambda(1520) \to p'K^-$ was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos$\theta_{K^+}$,…
The transition helicity amplitudes from the proton ground state to the $P_{11}(1440)$ and $D_{13}(1520)$ excited states ($\gamma_{v}pN^*$ electrocouplings) were determined from the analysis of nine independent one-fold differential $\pi^{+}…
The $\gamma p \to K^+ \pi^0 \Lambda$ and $\gamma p \to K^+ \pi \Sigma $ reactions are studied in the kinematic region where the $\pi^0 \Lambda$(1116) and $\pi\Sigma$(1192) pairs originate dominantly from the decay of the $\Sigma$(1385) and…
We investigate photoproduction of eta mesons off protons and neutrons within a coupled-channels effective-Lagrangian method which is based on the K-matrix approach. The two-body final channels included are pi-N, eta-N, phi-N, rho-N,…
This work used the {\gamma}-activation approach to conduct tests at bremsstrahlung end-point energies of 10-23 MeV utilising the MT-25 microtron beam. The experimental values of relative yields and cross sections per equivalent quantum of…
We derive a set of new formulas for various distributions in dilepton production via virtual photon bremsstrahlung from pseudoscalar mesons and unpolarized spin-one-half fermions. These formulas correspond to the leading and sub-leading…
An experiment was carried out with the NKS2+ in 2010 at the Research Center for Electron Photon Science (ELPH), in which tagged photon beams in the range of 0.8 $\le$ $E_{\gamma}$ $\le$ 1.1 GeV were impinged on a liquid $^2$H target…
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 report the first beam-target double-polarization asymmetries in the $\gamma + n(p) \rightarrow \pi^- + p(p)$ reaction spanning the nucleon resonance region from invariant mass $W$= $1500$ to $2300$ MeV. Circularly polarized photons and…
Angular distributions of differential cross sections from the latest CLAS data sets \cite{bradford}, for the reaction ${\gamma}+p {\to} K^{+} + {\Lambda}$ have been analyzed using associated Legendre polynomials. This analysis is based upon…
Differential cross sections and photon-beam asymmetries for the gamma p -> pi- Delta++(1232) reaction have been measured for 0.7<cos(theta)<1 and Egamma=1.5-2.95 GeV at SPring-8/LEPS. The first-ever high statistics cross section data are…
Photoproduction of the $\Lambda^*(1520)$ resonance of spin-parity ${3\over2}^-$ off the proton target is investigated within the Regge framework where the $t$-channel reggeization is applied for the $K(494)+K^*(892)+K_2^*(1430)$ exchanges…
We investigate photoproduction of $\phi$-mesons off protons within a coupled-channel effective-Lagrangian method which is based on the K-matrix approach. Since the threshold energy of the $K\Lambda(1520)$ channel is close to that of $\phi…
Cross-sections and recoil polarizations for the reactions gamma + p --> K^+ + Lambda and gamma + p --> K^+ + Sigma^0 have been measured with high statistics and with good angular coverage for center-of-mass energies between 1.6 and 2.3 GeV.…
In this paper, we extend the study of bremsstrahlung photon production in a quark-gluon plasma to the cases of soft static photons and hard real photons. The general framework of this study is the effective perturbative expansion based on…
Positivity constraints have proved to be important for spin observables of exclusive reactions involving polarized initial and final particles. Attention is focused in this note on the photoproduction of pseudoscalar mesons from spin 1/2…
The $\omega$-meson photoproduction, $\gamma+p\to p+\omega$, is studied in the framework of a model, containing $\pi$-meson exchange in t-channel and nucleon-exchange in s- and u-channels. Considering both $\omega NN$-coupling constants in…