Feasibility study for the detection ofD⁰ K   decays in Pb Pb collisions at LHC with ALICE

Abstract

The ALICE experiment at the CERN LHC collider is devoted to the study of heavy-ion collisions at a centre of mass energy of 5.5 TeV per nucleon.The study of open charm production in nucleus-nucleus collisions at the LHC allows investigation of the mechanisms of heavy quark production and energy loss in the hot and dense medium formed in the early stage of the collision. In addition, the open charm production cross section is the natural normalization for the study of J/ψ production. The reconstruction of exclusive hadronic decays of charm particles is the only way to obtain a direct measurement of their transverse momentum distribution. We present the results of a feasibility study for the detection of D 0 → K − π + decays in Pb-Pb collisions with ALICE.

Charm quenching in heavy-ion collisions at the LHC

“…In order to study the nuclear modification of the D mesons in central Pb-Pb collisions at the LHC, we generate c quarks with PYTHIA using a set of parameters that allows to reproduce the p t distribution given by next-to-leading order (NLO) perturbative QCD (pQCD) calculations [13] with charm mass m c = 1.2 GeV and factorization and renormalization scales µ F = µ R = 2 m t , where m t = p 2 t + m 2 c is the c-quark transverse mass, (see [14]). We use CTEQ4L parton distribution functions (PDFs) and we include, for Pb-Pb, their nuclear modification (shadowing) in the EKS98 parameterization [15].…”

“…The expected production yields per unit of rapidity at central rapidity for D 0 (and D 0 ) mesons decaying in a K ∓ π ± pair, estimated [14] on the basis of NLO pQCD calculations with m c = 1.2 GeV and µ F = µ R = 2 m t , are BR × dN/dy = 5.3 × 10 −1 in central (0-5%) Pb-Pb collisions at √ s NN = 5.5 TeV and BR × dN/dy = 7.5 × 10 −4 in pp collisions at √ s = 14 TeV. The main feature of the D 0 decay topology is the presence of two tracks displaced from the interaction point by, on average, 50 µm, for D-meson p t ≃ 0.5 GeV, to 120 µm, for p t > ∼ 5 GeV.…”

“…The low value of the magnetic field, 0.4 T, and the K/π separation in the TOF detector extend the D 0 measurement down to p t ≈ 1 GeV. The analysis strategy and the pertinent selection cuts were studied with a detailed simulation of the detector geometry and response, including the main background sources [18,21]. The accessible p t range is 1-14 GeV for Pb-Pb and 0.5-14 GeV for pp collisions.…”

Charm and Beauty at the LHC

“…In Table 1 we report the cc and bb yields in p-Pb and Pb-Pb collisions, obtained including in the NLO pQCD calculation the EKS98 parameterization [5] of the PDFs nuclear modification and applying binary scaling [3]. The charm (beauty) cross-section reduction induced by shadowing is about 35% Table 1 Expected QQ yields at the LHC, from NLO pQCD [3].…”

“…The charm (beauty) cross-section reduction induced by shadowing is about 35% Table 1 Expected QQ yields at the LHC, from NLO pQCD [3]. For p-Pb and Pb-Pb, PDF shadowing is included and binary scaling is applied.…”