On source parameters from particle correlations and spectra

The correlation between the mean transverse momentum and the harmonic flow coefficients is an observable which is of great interest, it is sensitive to shape fluctuations in the initial state of a relativistic nuclear collision. The measurement of that correlation coefficient in central collisions allows one to infer on the intrinsic deformation and structure of the colliding nuclei. We propose to study the momentum dependent covariance and correlation coefficient between the...

The correlation function observed in high-energy collision experiments encodes critical information about the emitted source and hadronic interactions. While the proton-proton interaction potential is well constrained by nucleon-nucleon scattering data, these measurements offer a unique avenue to investigate the proton-emitting source, reflecting the dynamical properties of the collisions. In this Letter, we present an unbiased approach to reconstruct proton-emitting sources ...

A 3-fluid hydrodynamic model for simulating relativistic heavy-ion collisions is introduced. Alongside with two baryon-rich fluids, the new model considers time-delayed evolution of a third, baryon-free (i.e. with zero net baryonic charge) fluid of newly produced particles. Its evolution is delayed due to a formation time, during which the baryon-free fluid neither thermalizes nor interacts with the baryon-rich fluids. After the formation it starts to interact with the baryon...

Transverse mass spectra of pions and protons measured in central collisions of heavy ions at the SPS and at RHIC are compared to a hydrodynamic parameterization. While the chemical temperature needed at RHIC is significantly higher compared to SPS, the spectra may be described using kinetic freeze-out parameters which are similar for both beam energies. At RHIC either the temperature or the flow velocity is higher, but the data provide no unambiguous proof for much stronger t...

An analytically calculable model has been proposed recently for the simultaneous description of particle spectra and correlations, which is able to explain in a natural manner the $m_t$ scaling of the radius parameters of the Bose--Einstein correlation functions. We present here preliminary results on fitting this model to data sampled by NA44 collaboration in central S + Pb reactions at CERN SPS, which indicate that both pions and kaons freeze-out at a surprisingly low tempe...

We investigate the role of the central two-body nucleon-nucleon correlations on typical quantities observed in relativistic heavy-ion collisions. Basic correlation measures, such as the fluctuations of the participant eccentricity, initial size fluctuations, or the fluctuations of the number of sources producing particles, are sensitive at the level 10-20% to the inclusion of the two-body correlations. However, the realistic correlation function gives virtually indistinguisha...

We introduce a new realistic expanding source model for invariant one-particle multiplicity distributions and two-particle correlations in nearly central relativistic heavy-ion collisions that contains nine adjustable parameters, which are necessary and sufficient to properly characterize the gross properties of the source during its freezeout from a hydrodynamical fluid into a collection of noninteracting, free-streaming hadrons. These nine physically relevant parameters fal...

The "unreasonable effectiveness" of relativistic fluid dynamics in describing high energy heavy-ion and even proton-proton collisions are demonstrated and discussed. Several recent ideas of optimizing relativistic fluid dynamics for the specific challenges posed by such collisions will be presented, and some thoughts will be offered why the framework works better than originally expected. I will also address the unresolved question where exactly hydrodynamics breaks down, and...

In this work, we study the two-particle correlations regarding a peripheral tube model. From our perspective, the main characteristics of the observed two-particle correlations are attributed to the multiplicity fluctuations and the locally disturbed one-particle distribution associated with hydrodynamic response to the geometric fluctuations in the initial conditions. We investigate the properties of the initial conditions and collective flow concerning the proposed model. I...

Transverse momentum spectra of identified particles produced in heavy-ion collisions at the Large Hadron Collider are described with relativistic fluid dynamics. We perform a systematic comparison of experimental data for pions, kaons and protons up to a transverse momentum of 3 GeV$/c$ with calculations using the FluiduM code package to solve the evolution equations of fluid dynamics, the TrENTo model to describe the initial state and the FastReso code to take resonance deca...