A. Bialas

Wounded quarks and diquarks in heavy ion collisions

Abstract A model in which the soft collisions of the nucleon are described in terms of interactions of its two constituents (a quark and a diquark) is proposed. When adjusted to describe precisely the elastic proton–proton scattering data and supplemented with the idea of wounded constituents, the model accounts rather well for the centrality dependence of particle production in the central rapidity region at RHIC energies.

Early evolution of transversally thermalized partons

The idea that the parton system created in relativistic heavy-ion collisions (i) emerges in a state with transverse momenta close to thermodynamic equilibrium and (ii) its evolution at early times is dominated by the 2-dimensional (transverse) hydrodynamics of the ideal fluid is investigated. It is argued that this mechanism may help to solve the problem of early equilibration.

Intermittency and the Schwinger tunneling mechanism

Abstract The creation of qq pairs in an external field by tunneling (Schwinger mechanism) is applied in the context of a color tube model to e + e − annihilation. The model incorporates the strong fluctuations of the field implied by the charge shielding due to created pairs. Random cascading phenomena and various interactions among the pairs are observed in a Monte Carlo simulation. They give rise to a clear intermittency signal, compatible with recent experimental analyses.

Hydrodynamics and long range correlations

It is shown that the recently proposed method of studying the long-range correlations in multiparticle production can be effectively used to verify the hydrodynamic nature of the longitudinal expansion of the partonic system created in the collision. The case of ALICE detector is explicitly considered.

Finite size of hadrons and Bose-Einstein correlations

Abstract It is observed that the finite size of hadrons produced in high energy collisions implies that their positions are correlated, since the probability to find two hadrons on top of each other is highly reduced. It is then shown that this effect can naturally explain the values of the correlation function below one, observed at LEP and LHC for pairs of identical pions.

Hidden asymmetry and long range rapidity correlations

Abstract Interpretation of long-range rapidity correlations in terms of the fluctuating rapidity density distribution of the system created in high-energy collisions is proposed. When applied to recent data of the STAR Collaboration, it shows a substantial asymmetric component in the shape of this system in central Au–Au collisions, implying that boost invariance is violated on the event-by-event basis even at central rapidity. This effect may seriously influence the hydrodynamic expansion of the system.

Early dynamics of transversally thermalized matter

We argue that the idea that the parton system created in relativistic heavy-ion collisions is formed in a state with transverse momenta close to thermodynamic equilibrium and its subsequent dynamics at early times is dominated by pure transverse hydrodynamics of the perfect fluid is compatible with the data collected at RHIC. This scenario of early parton dynamics may help to solve the problem of early equilibration.

Coincidence probability as a measure of the average phase-space density at freeze-out

It is pointed out that the average semi-inclusive particle phase-space density at freeze-out can be determined from the coincidence probability of the events observed in multiparticle production. The method of measurement is described and its accuracy examined.