Related papers: Nucleon Resonance Electrocouplings from the CLAS M…
A parameter-free evaluation of the $N - P_{11}(1440)$ electromagnetic transition form factors is performed within a light-front constituent quark model, using for the first time the eigenfunctions of a mass operator which generates a large…
Studies of the spectrum of hadrons and their structure in experiments with electromagnetic probes offer unique insight into many facets of the strong interaction in the regime of large quark-gluon running coupling, {\it i.e.} the regime of…
The exclusive electroproduction of $\pi^+$ above the resonance region was studied using the $\rm{CEBAF}$ Large Acceptance Spectrometer ($\rm{CLAS}$) at Jefferson Laboratory by scattering a 6 GeV continuous electron beam off a hydrogen…
An effective Lagrangian calculation of pion photoproduction including all nucleon resonances up to $\sqrt s = 1.7$ GeV is presented. We compare our results to recent calculations and show the influence of different width parametrizations…
Photoproduction of mesons off quasi-free nucleons bound in the deuteron allows to study the electromagnetic excitation spectrum of the neutron and the isospin structure of the excitation of nucleon resonances. The database for such…
We review recent progress in our understanding of the nucleon excitation spectrum. Thanks to dedicated efforts at facilities such as ELSA, MAMI and Jefferson Lab, several new nucleon resonances have been discovered, and evidence for…
Photoproduction of charged pions pairs off protons is studied within the invariant masses of the final state hadrons from 1.6 to 2.4 GeV at the Thomas Jefferson National Accelerator Facility with the CLAS detector. The data are included in…
We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $\Lambda$ and $\Sigma ^{0}$ of the CLAS and SLAC-E84 collaborations, by considering constituent-counting rule…
A search has been performed for heavy resonances decaying to ZZ or ZW and for axion-like particles (ALPs) mediating nonresonant ZZ or ZH production, in final states with two charged leptons ($\ell$ = e, $\mu$) produced by the decay of a Z…
The main goal of the experimental programs on ultra-relativistic heavy ion collisions at the LHC is the production and characterization of the Quark Gluon Plasma (QGP), a phase of nuclear matter in which strongly interacting constituents…
We discuss recent results from CLAS on electromagnetic resonance transition amplitudes and their dependence on the distance scale ($Q^2$). From the comparison of these results with most advanced theoretical calculations within QCD-based…
Hyperon production off the proton in the $K^0 \Sigma^+$ channel has been studied at the tagged photon beam facility at the ELSA electron accelerator in Bonn. This experiment was part of a series of neutral meson production experiments on…
I present the calculation of the $\pi^+\gamma^\star\to\pi^+\pi^0$ transition amplitude from quantum chromodynamics performed by the Hadron Spectrum Collaboration. The amplitude is determined for a range of values of the photon virtuality…
Measurements of the top quark production cross section in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented. The measurements require no, one or two electrons or muons in the final state (single…
The Roper resonance is considered as a mixed state of a three-quark core configuration and a hadron molecular component N+sigma. Based on this ansatz we study electroproduction of the Roper resonance. The strong and electromagnetic…
Electro-production of several pentaquark states is investigated in this paper. eSTARlight package is adapted to study the electro-production of $J/\psi$ and $\Upsilon (1S)$ via pentaquark $P_c$ and $P_b$ resonance channels in $e p \to e…
Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/$\psi$ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function…
The $f_0$(1500) meson resonance is one of several contenders to have significant mixing with the lightest glueball. This resonance is well established from several previous experiments. Here we present the first photoproduction data for the…
We present a lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. The study is based on the PACS-CS ensemble of gauge configurations with…
Using $1.7 \pm 0.1\,\mathrm{nb^{-1}}$ of lead-lead ($A = 208$) collision data recorded by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top quark pair ($\mathrm{t\bar{t}}$) production. The…