Predictions for low-p{sub T} and high-p{sub T} hadron spectra in nearly central Pb+Pb collisions at {radical}(s{sub NN})=5.5 TeV tested at {radical}(s{sub NN})=130 and 200 GeV

Journal Article · Sat Oct 01 00:00:00 EDT 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.72.044904· OSTI ID:20699080

Eskola, K J; Niemi, H; Ruuskanen, P V ^[1]; Honkanen, H ^[1]; Raesaenen, S S ^[1]

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1. Department of Physics, P.B. 35, FIN-40014 University of Jyvaeskylae (Finland)

We study the hadron spectra in nearly central A+A collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) in a broad transverse momentum range. We cover the low-p{sub T} spectra using longitudinally boost-invariant hydrodynamics with initial energy and net-baryon number densities from the perturbative QCD (pQCD)+saturation model. Buildup of the transverse flow and sensitivity of the spectra to a single decoupling temperature T{sub dec} are studied. Comparison with RHIC data at {radical}(s{sub NN})=130 and 200 GeV suggests a rather high value T{sub dec}=150 MeV. The high-p{sub T} spectra are computed using factorized pQCD cross sections, nuclear parton distributions, fragmentation functions, and describing partonic energy loss in the quark-gluon plasma by quenching weights. Overall normalization is fixed on the basis of p+p(p) data and the strength of energy loss is determined from RHIC Au+Au data. Uncertainties are discussed. With constraints from RHIC data, we predict the p{sub T} spectra of hadrons in 5% most central Pb+Pb collisions at the LHC energy {radical}(s{sub NN})=5500 GeV. Because of the closed framework for primary production, we can also predict the net-baryon number at midrapidity, as well as the strength of partonic energy losses at the LHC. Both at the LHC and RHIC, we recognize a rather narrow crossover region in the p{sub T} spectra, where the hydrodynamic and pQCD fragmentation components become of equal size. We argue that in this crossover region the two contributions are to a good approximation mutually independent. In particular, our results suggest a wider p{sub T} region of applicability for hydrodynamical models at the LHC than at RHIC.

• OSTI ID: 20699080
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevC.72.044904; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON NUMBER
BROOKHAVEN RHIC
CERN LHC
COMPARATIVE EVALUATIONS
CROSS SECTIONS
DECOUPLING
DENSITY
ENERGY LOSSES
GEV RANGE
HADRONS
LEAD 208 REACTIONS
LEAD 208 TARGET
NUCLEAR FRAGMENTATION
PARTON MODEL
PARTONS
PERTURBATION THEORY
QUANTUM CHROMODYNAMICS
QUARK MATTER
TEV RANGE
TRANSVERSE MOMENTUM