相关论文: Jpsi and dielectron photoproduction measurements w…

High energy ultra-peripheral collisions (UPC) of heavy-ions generate strong electromagnetic fields which open the possibility to study gamma-gamma and gamma-nucleus processes in a kinematic regime so far unexplored. We report on preliminary…

We present the first measurement of photoproduction of J/psi and of two-photon production of high-mass e+e- pairs in electromagnetic (or ultra-peripheral) nucleus-nucleus interactions, using Au+Au data at sqrt(s_NN) = 200 GeV. The events…

Ultra-peripheral collisions (UPC) of heavy-ions involve long range electromagnetic interactions at impact parameters twice larger than the nuclear radius, where no nucleon-nucleon collisions occur. The first measurement of photoproduction…

$J/\psi$ measurements in $p+p$ and $d+Au$ collisions serve as crucial references to understand the $J/\psi$ production in $Au+Au$ collisions at RHIC where quark gluon plasma (QGP) is expected to be formed. They also provide important clues…

Direct photon production in Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV has been measured in the $p_T$ range of 1$<$$p_T$$<$5 GeV/$c$. The yield as acfunction of centrality is in agreement with published data of the RHIC 2002 run, and with…

J/psi production in d+Au and p+p collisions at sqrt(s_NN) = 200 GeV has been measured by the PHENIX experiment at rapidities -2.2 < y < +2.4. The cross sections and nuclear dependence of J/\psi production versus rapidity, transverse…

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…

Measurements of J/$\psi$ production by the PHENIX experiment in p+p, d+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV are reviewed. The results show a suppression beyond what can be explained by cold nuclear matter effects in the…

Results from the PHENIX experiment at RHIC on direct photon production in p+p, d+Au, and Au+Au collisions at sqrt(s_NN) = 200 GeV are presented. In p+p collisions, direct photon production at high p_T behaves as expected from perturbative…

Measurements of exclusive $J/\psi$, $\psi(2s)$, and electron-positron ($e^{+}e^{-}$) pair photoproduction in Au$+$Au ultra-peripheral collisions are reported by the STAR experiment at $\sqrt{s_{_\mathrm{NN}}}=200~\rm{GeV}$. We report…

The production of electron pairs with transverse momentum between 1 and 5 GeV/c and m< 300 MeV has been measured at mid-rapidity in 200 GeV p+p and Au+Au collisions by the PHENIX experiment at RHIC. A significant excess above the hadronic…

PHENIX has measured $J/\psi$ production at backward, central and forward rapidities both in p+p and d+Au collisions at $\sqrt{s_{NN}}=200$ GeV during the third run of the RHIC collider. From the p+p collisions, we measure the total J/$\psi$…

The production of the low-mass dielectrons is considered to be a powerful tool to study the properties of the hot and dense matter created in the ultra-relativistic heavy-ion collisions. We present the preliminary results on the first…

PHENIX preliminary results on the $J/\Psi$ production in $Cu+Cu$ and $Au+Au$ collisions at $\sqrt{s_{NN}}=200$ GeV are presented. They are compared to results from lower energy experiments NA50 and NA60 at CERN SPS and to expectations from…

The ALICE collaboration has made the first measurement at the LHC of J/$\psi$ photoproduction in ultra-peripheral Pb-Pb-collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV. The J/$\psi$ is identified via its dimuon decay in the forward rapidity…

We report on the first measurement of diffractive J/psi production in Ultraperipheral Au+Au collisions at \sqrt{s_{NN}}=200 GeV.

We report a measurement of exclusive $J/\psi$ photoproduction in Au$+$Au ultra-peripheral collisions at $\sqrt{s_{_\mathrm{NN}}}=200$ GeV using the STAR detector. For the first time, i) the rapidity correlation between $J/\psi$…

Ultra-peripheral collisions (UPC) are events characterised by large impact parameters between the two projectiles, larger than the sum of their radii. In UPCs, the protons and ions accelerated by the LHC do not interact via the strong…

The ALICE collaboration performed the first rapidity-differential measurement of coherent J/$\psi$ photoproduction in ultra-peripheral Pb-Pb collisions at a center-of-mass energy $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV. The J/$\psi$ is detected via…

Photon-photon reactions and the production of J/$\psi$ meson through photonuclear reactions have been extensively studied in ultra-peripheral heavy-ion collisions, in which the impact parameter is larger than twice the nuclear radius. In…