Hou Zhao-Yu

Influence of the Nucleon Hard Partons Distribution on J/Psi Suppression in a GMC Framework

In a Glauber Monte Carlo framework, taking account of the transverse spatial distribution of hard partons in the nucleon, we analyse the nuclear modification factor RdAu for J/ψ in d+Au collisions with the EPS09 shadowing parametrization. After the influence of nucleon hard partons distribution is considered, a clearly upward correction is revealed for the dependence of RdAu on Ncoll in peripheral d+Au collisions, however, an unconspicuous correction is shown for the results versus pT . The theoretical results are in good agreement with the experimental data from PHENIX. PACS: 25.75.-q, 24.85.+p, 12.38.Bx For J/ψ production is sensitive to both cold nuclear matter (CNM) and Quark-Gluon Plasma (hot-dense matter)[1], the “normal suppression”in the CNM should be subtracted in any interpretation of charmonium production in heavy ion collisions. The Glauber Monte Carlo (GMC) approach[2−6], which can simulate experimentally observable quantities and analyse real data, is an ideal tool to study the CNM effects provided in deuteron-gold (d+Au) collisions[7]. In the framework of the GMC, only the essential J/ψ production process[8], g+ g → cc̄, is considered. Thus, the subprocess cross section can be obtained by extracting from the proton-proton (p+p) experimental data[9] and given as the Monte Carlo inputs of rapidity (y) and transverse momentum (pT ) [3,4]. The shadowing and “normal nuclear absorption”effects, which are two dominant CNM effects at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies, can also be considered properly in the GMC framework. Since shadowing should depend on the spatial position of the interaction parton within the nucleus, the inhomogeneous shadowing effect[10,11] should also be taken into account. In this paper, the latest shadowing parametrization EPS09 (Eskola, Paukkunen and Salgado)[12] is used. At ultra-high energy domain, the mechanism of inelastic hadronic collisions is dominated by the contribution from small-x gluons and the influence of the transverse spatial distribution of hard partons in the nucleon become important[13,14]. Unfortunately, comparing with the longitudinal momentum distribution of partons in the nucleon, the measurements of the transverse spatial distribution of partons are rather limited[15]. In this paper, two kinds of hard partons distributions in the nucleon are used. One is assumed that the hard partons are uniformly distributed in a hard sphere nucleon, the other is derived from fits to J/ψ photo-production data at HERA and FNAL[13,15]. The corresponding results with both of them will be given in the following part of the paper. Supported by Natural Science Foundation of Hebei Province(A2008000421) E-mail:whmw@sina.comIn a Glauber Monte Carlo framework, taking into account the transverse spatial distribution of hard partons in the nucleon, we analyze the nuclear modification factor R(d) (Au) for J/psi in d+Au collisions with EPS09 shadowing parametrization. After the influence of nucleon hard partons distribution is considered, a clearly upward correction is revealed for the dependence of R(d Au) on N(coll) in peripheral d+Au collisions, however, an unconspicuous correction is shown for the results versus p(T). The theoretical results are in good agreement with the experimental data from PHENIX.

A Study on Radiative Dileptonic DecaysB0(Bs)→γℓ+ℓ−

We study the rare radiative dileptonic decays

Net-Baryon and Net-Kaon Rapidity Distributions in Ultrarelativistic Heavy-Ion Collisions

B^0(B_s)\to \gamma\ell^+\ell^-

Charm structure functions and gluon shadowing effects with the AdS/CFT model

(

J/ψ-N center of mass energy dependence of nuclear absorption effect on J/ψ production

\ell=e,\mu

Uncertainty Study of Bd(Bs) → γνν̄ Decays

) in the standard model. By using the

Uncertainty Study of Bd(Bs) → γνbar nu Decays

B

Cold nuclear matter effects on J/? production in d-Au collisions

meson wave function constrained by non-leptonic decays, the branching ratios turn out to be of the order of

Cold nuclear matter effects on J/ψ production in d-Au collisions

10^{-9}

Cold nuclear matter effects on J/ψ production in d-Au collisionsSupported by Innovation Foundation of Academy of Armored Forces Engineering of PLA (20062L10), and Natural Science Foundation of Hebei Province (A2005000535)

for