arXiv subjects
Publications and source records attributed to D. Peressounko.
We give an overview of photon physics which will be studied by the ALICE experiment in proton-proton and heavy ion collisions at LHC. We compare properties of ALICE photon detectors and estimate their ability to measure neutral meson and direct photon spectra as well as gamma-hadron and gamma-jet correlations in pp and Pb+Pb collisions.
The current status of the analysis of direct photon Bose-Einstein correlations in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV done by the PHENIX collaboration is summarized. All possible sources of distortion of the two-photon correlation function are discussed and methods to control them in the PHENIX experiment are presented.
Direct photon spectra measured at small $p_T$ in p+p, d+Au and Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV are presented. Several measurement techniques including statistical subtraction, tagging, and internal and external conversion were applied and found to produce consistent results. The p+p and d+Au results are found to be in very good agreement with pQCD predictions over the entire $p_T$ range. No excess of direct photons in Au+Au collisions with respect to binary scaled d+Au data is observed within systematic errors.
Direct photon yield measured in p+p and d+Au collisions at \sqrt{s} = 200 GeV with the PHENIX experiment is presented and compared to pQCD predictions. In the case of p+p collisions both the inclusive and isolated direct photon production cross-sections are measured. Relative contribution of isolated direct photons is somewhat below but still agree within errors with pQCD predictions. In the case of d+Au collisions no modifications due to presence of cold matter are found within errors.
We consider recent developments in the theory of the two-photon interferometry in ultrarelativistic heavy ion collisions with emphasis on the difference between photon and hadron interferometry. We review the available experimental results and discuss possibilities of measurement of the photon Bose-Einstein correlations in ongoing and future experiments.
We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.
We present final results from the WA98 experiment which provide first measurements of Bose-Einstein correlations of direct photons in ultrarelativistic heavy ion collisions. Invariant interferometric radii were extracted in the range $100<K_T<300$ MeV/c and compared to interferometric radii of charged pions. The yield of direct photons for $100<p_T<300$ MeV/c was extracted from the correlation strength parameter and compared to the yield of direct photons measured in WA98 at higher $p_T$ with the statistical subtraction method, and to predictions of a fireball model.