Related papers: Nuclear Gluon Shadowing via Continuum Lepton Pairs…
Opposite-sign lepton pairs ($ee$,$e\mu$ and $\mu\mu$) from open charm decay are proposed as a measure of nuclear shadowing effects. Via an approximate scaling the ratio of the dilepton spectra from $p+A$ to those from $pp$ reflects the…
Open charm production at the initial and the pre-equilibrium stages in nuclear collisions is studied. The pre-equilibrium contribution to open charm production in $A+A$ collisions at $\sqrt s=200 AGeV$ is shown to be very sensitive to…
Charm production from the direct reconstruction of $D^0$ ($D^0\to K\pi$ up to 2 GeV/$c$) and indirect lepton measurements via charm semileptonic decays ($c\to e+X$ at 0.9\textless$p_T$\textless5.0 GeV/$c$ and $c\to \mu+X$ at…
The possibility to observe the nuclear modification of the gluon distribution at small-x (gluon shadowing) using high-p_T prompt photon production at RHIC and at LHC is discussed. The per-nucleon ratio, sigma(p+A -> gamma+X) / A sigma(p+p…
We show estimates for shadowing of gluons at small values of $x$, appropriate to RHIC and LHC experiments using a new evolution equation which takes into account the effects of gluon recombination to all orders in gluon density. We show…
Results on physics at RHIC using outgoing leptons and photons will be presented from Au+Au collisions at nucleon-nucleon c.m. energies $\sqrt{s_{NN}}=130$ and 200 GeV and from p-p collisions at $\sqrt{s}=200$ GeV. Introduction and…
Open charm spectra at mid-rapidity from direct reconstruction of $D^{0}\to K\pi$ and indirect electron/positron measurements via charm semileptonic decay in p+p and d+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV are reported. The…
Nuclear shadowing and color glass condensate are possible only at sufficiently small x where parton clouds of different nucleons overlap in the longitudinal direction. Another condition vital for these effect, an overlap of partons in…
A validity of a recent estimate of an upper limit of charm production in central Pb+Pb collisions at 158 AGeV is critically discussed. Within a simple model we study properties of the background subtraction procedure used for an extraction…
The PHENIX experiement has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c^2 in p+p collisions at sqrt(s)=200 GeV. The contributions from light meson decays to e^+e^- pairs have been determined based on measurements of…
The interplay of nuclear effects on the p_T > 2 GeV inclusive hadron spectra in d+Au and Au+Au reactions at root(s) = 17, 200, 5500 GeV is compared to leading order perturbative QCD calculations for elementary p+p (p-bar+p) collisions. The…
In this thesis, we present the measurements of $D^{0}\to K\pi$ at low $p_T$ ($p_T\leq2$ GeV/$c$) and non-photonic electron spectra ($0.9\leq p_T\leq5$ GeV/$c$) from $D^0$ semi-leptonic decay. In addition, we use a newly proposed technique…
We evaluate nuclear shadowing of the total cross section of charm particles production in DIS within the framework of the Gribov theory of nuclear shadowing using as input the recent QCD Pomeron parton density analysis of the HERA…
There is a major need to better constrain nuclear parton densities in order to provide reliable perturbative QCD predictions at the LHC as well as to probe possible non-linear evolution at small values of x. In these proceedings, we discuss…
The QCD factorization theorem for diffractive processes in DIS is used to derive formulae for the leading twist contribution to the nuclear shadowing of parton distributions in the low thickness limit. Based on the current analyzes of…
Mid-rapidity open charm spectra from direct reconstruction of $D^{0}$($\bar{D^0}$)$\to K^{\mp}\pi^{\pm}$ in d+Au collisions and indirect electron/positron measurements via charm semileptonic decays in p+p and d+Au collisions at \srt = 200…
A systematic determination of the gluon distribution is of fundamental interest in understanding the parton structure of nuclei and the QCD dynamics. Currently, the behavior of this distribution at small $x$ (high energy) is completely…
Inclusive transverse momentum spectra of single electrons from Au+Au collisions have been measured at $\sqrt{s_{NN}}$ = 130 GeV and 200 GeV at midrapidity by the PHENIX experiment at RHIC. After subtraction of background from photon…
Measurements of dilepton production from charm decay and Drell-Yan processes respectively probe the gluon and sea quark distributions in hadronic collisions. In nucleus-nucleus collisions, these hard scattering processes constitute a…
The interaction of spatially small dipoles with nucleons, nuclei is calculated in the DGLAP approximation at the top of HERA energies and found to be close to the $S$-channel unitarity limit in the case of the color octet dipoles. The DGLAP…