On predictions of the first results from RHIC

In this talk, I will discuss the predictions of the first results from RHIC: the charged particle multiplicity $dN_{\rm ch}/d\eta$, its centrality dependence and the elliptic flow $v_2$.Comment: A plenary review talk at Quark Matter 2001, Stony Brook, USA, January 2001, 10 page

Note on proton-antiproton suppression in 200 AGeV Au-Au collisions

We discuss the measured nuclear suppression of p + pbar production in 200 AGeV Au-Au collisions at RHIC within radiative energy loss. For the AKK set of fragmentation functions, proton production is dominated by gluons, giving rise to the expectation that the nuclear suppression for p + pbar should be stronger than for pions due to the stronger coupling of gluons to the quenching medium. Using a hydrodynamical description for the soft matter evolution, we show that this is indeed seen in the calculation. However, the expected suppression factors for pions and protons are sufficiently similar that a discrimination with present data is not possible. In the high p_T region above 6 GeV where the contributions of hydrodynamics and recombination to hadron production are negligible, the model calculation is in good agreement with the data on p + pbar suppression.Comment: 3 pages, 2 figures, slightly expanded versio

Minijets in ultrarelativistic heavy ion collisions at RHIC and LHC

Recent results on minijet production in nuclear collisions at the RHIC and LHC energies are reviewed. Initial conditions of the QGP at $\tau=0.1$ fm$/c$, especially parton chemistry, thermalization and net baryon number-to-entropy ratio are discussed. Also, contribution of minijets from a hard BFKL-pomeron ladder will be estimated

Hard dihadron correlations in heavy-ion collisions at RHIC and LHC

High transverse momentum (P_T) processes are considered to be an important tool to probe and understand the medium produced in ultrarelativistic heavy-ion collisions via the interaction of hard, perturbatively produced partons with the medium. In this context, triggered hard dihadron correlations constitute a class of observables set between hard single inclusive hadrons (dominated by the leading jet fragments) and fully reconstructed jets - while they probe some features of the perturbative QCD evolution of a parton shower in the medium, they do not suffer from the problem of finding a suitable separation between soft perturbative (jet-like) and soft non-perturbative (medium-like) physics as the identification of full jets does. On the other hand, the trigger requirement introduces non-trivial complications to the process, which makes the medium-modification of the correlation pattern difficult and non-intuitive to understand. In this work, we review the basic physics underlying triggered dihadron correlations and make a systematic comparison of several combinations of medium evolution and parton-medium interaction models with the available data from 200 AGeV Au-Au collisions at RHIC. We also discuss the expected results for 2.76 ATeV Pb-Pb collisions at the LHC.Comment: 13 pages, 7 figures, submitted to PR