We compute the thermal photon spectrum in the Pb+Pb collisions at the CERN SPS energy using thermal emission rates and a hydrodynamic description for the evolution of produced hot matter and compare our results with the measurements of the excess photons by the WA98 collaboration. Our results show that the measured photon spectrum can be reproduced with realistic initial conditions which take p...

Associated production of Intermediate Higgs or Z-boson with t ¯ t pair in γγ collision ABSTRACT 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 ¯ t pair in γγ collisions are studied. Since IMH is very unlikely to decay into t ¯ ...

Relativistic heavy ion beams are an intense source of (quasireal) photons with a spectrum extending up to several hundred GeV, due to the high charge Z and the large energy of the ions. In this note we discuss the possibility of using this in peripheral collisions for photon-photon physics. We discuss the total luminosities that can be achieved with diierent ion species. In order to suppress ce...

The status of analysis of processes with hard photon emitted from the initial state (ISR) at BABAR is presented. We tag events by the presence of a hard photon in the detector, then reconstruct μμ and several exckusive hadronic final states. The invariant mass of the final state determines an effective collision center of mass energy at which these measurements can be compared with results from...

Interaction of an electron with the counter-propagating electromagnetic wave is studied theoretically and particle-in-cell simulations in regime quantum radiation reaction. We find energy center laser pulse, as it a key factor for testing non-linear electrodynamics vacuum properties laser-electron collision multi-photon Compton scattering Cherenkov radiation. With multiparametric analysis we pr...

The density of gluons produced in the central rapidity region of a heavy ion collision is poorly known. We investigate the influence of the Landau-Pomeranchuk effect (LPE) on the transverse momentum distribution of photons and gluons radiated by a quark propagating through nuclear matter. We describe the case that the radiation time substantially exceeds the nuclear radius (which is the relevan...

We study the horizontal transport of ultracold atoms over macroscopic distances of up to 20 cm with a moving 1D optical lattice. By using an optical Bessel beam to form the optical lattice, we can achieve almost homogeneous trapping conditions over the full transport length, which is necessary to hold the atoms against gravity for such a wide range. Fast transport velocities of up to 6m/s (corr...

This presentation summarizes the results on ultra-peripheral collisions obtained at RHIC. It also discusses some aspects of the corresponding electromagnetic interactions in pp and pp collisions. Ultra-peripheral nucleus-nucleus collisions are defined as collisions in which the distance between the nuclei is large enough that no purely hadronic interactions can occur. This roughly means impact ...

We present the multiplicity and pseudorapidity distributions of photons produced in Au+Au and Cu+Cu collisions at √ sNN = 62.4 and 200 GeV. The photons are measured in the region −3.7 < η < −2.3 using the photon multiplicity detector in the STAR experiment at RHIC. The number of photons produced per average number of participating nucleon pairs increases with the beam energy and is independent ...