Related papers: Novel azimuthal observables from two-photon collis…
High energy photons originating from the electromagnetic field of ultrarelativistic lead nuclei can interact with the other lead ion. These reactions are studied in the ultra-peripheral heavy ion collisions to probe the physics of strong…
The measurement of gamma+jet events with a direct photon in coincidence with an energetic parton can provide unique insights into the propagation and fragmentation of the parton in the presence of the hot and dense medium created in…
Future planned lepton colliders, both in the circular and linear configurations, can effectively work as virtual and quasi-real photon-photon colliders and are expected to stimulate an intense physics program in the next few years. In this…
The first measurement of the dependence of $\gamma\gamma$ $\to$ $\mu^{+}\mu^{-}$ production on the multiplicity of neutrons emitted very close to the beam direction in ultraperipheral heavy ion collisions is reported. Data for lead-lead…
Helicity amplitudes and differential cross section of high-energy $e^+e^-$ photoproduction accompanied by bremsstrahlung in the electric field of a heavy atom are derived. The results are exact in the nuclear charge number and obtained in…
Using the general helicity formula for $\gamma^* \gamma^*$ collisions, we are showing that it should be possible to determine a number of independent ``structure functions'', i.e. linear combinations of elements of the two-photon helicity…
The measurement of two-particle angular correlation functions in high-multiplicity $e^+e^-$ collisions at $\sqrt{s}=10.52$ GeV is reported. In this study, the $89.5~{\text{fb}}^{-1}$ of hadronic $e^+e^-$ annihilation data collected by the…
A single-spin asymmetry in the distribution of exclusively produced pi^+ mesons azimuthally around the virtual photon direction relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of…
In this review we discuss the observable consequences of in-medium changes of hadronic properties in reactions with elementary probes, and in particular photons, on nuclei. After an outline of the theoretical method used we focus on a…
Photon-photon linear colliders can be realized by laser back-scattering technique on the next generation linear $e^+e^-$ colliders. Here the associated productions of an intermediate mass Higgs (IMH) or Z-boson with $t \bar t$ pair in…
The production of a pair of $\tau$ leptons via photon-photon fusion, $\gamma\gamma$ $\to$ $\tau\tau$, is observed for the first time in proton-proton collisions, with a significance of 5.3 standard deviations. This observation is based on a…
The presented results are the first measurements at RHIC for direct $\gamma$-charged hadron azimuthal correlations in heavy ion collisions. We use these correlations to study the color charge density of the medium through the medium-induced…
Results of a measurement of dimuon photoproduction in non-ultraperipheral Pb+Pb collisions at $\sqrt{s_{_\mathrm{NN}}} = 5.02$ TeV are presented. The measurement uses ATLAS data from the 2015 and 2018 Pb+Pb data-taking periods at the LHC…
We report measurements of the asymmetry A_parallel for inclusive hadron production on longitudinally polarized proton and deuteron targets by circularly polarized photons. The photons were produced via internal and external bremsstrahlung…
We consider the cos(phi) dependence of the longitudinal double-spin asymmetry for charged pion electroproduction in semi-inclusive deep inelastic scattering, emphasizing intrinsic transverse momentum effects. This azimuthal asymmetry allows…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
We examine the possibility of using single-Higgs production at an $e^+e^-$ collider with polarized beams to measure, or constrain, indirectly a possible anomalous triple-Higgs coupling, which can contribute to the process via one-loop…
Hard photon emitted from energetic heavy ion collisions is of very interesting since it does not experience the late-stage nuclear interaction, therefore it is useful to explore the early-stage information of matter phase. In this work, we…
In this paper, we present the first complete treatment of incoherent photon-initiated production in ultraperipheral heavy ion collisions, focussing on the dilepton and diphoton final states. In the former case we compare to the ATLAS…
We argue that the large instanton induced Pauli form factor in polarized proton-proton scattering may cause, through topological fluctuations, substantial charge-dependent azimuthal correlations for pi^+/pi^- production in peripheral heavy…