arXiv subjects

Fernando Gardim

Publications and source records attributed to Fernando Gardim.

3 recordsLinked to original sources

arXiv2025

NuclearConfectionery: Multi-stage Simulation Framework for Modeling Relativistic Heavy-ion Collisions

We present the NuclearConfectionery, a modular framework for simulating the full dynamical evolution of relativistic heavy-ion collisions. Its core hydrodynamic module, CCAKE 2.0, represents a major advance over previous SPH-based relativistic hydrodynamic codes. CCAKE 2.0 simultaneously evolves energy-momentum and multiple conserved charges (B, S, Q) with a four-dimensional equation of state, and can be run in either Cartesian or hyperbolic coordinates, enabling consistent simulations from the RHIC Beam Energy Scan to LHC energies. We have implemented a particlization module that supports global BSQ charge conservation on the freeze-out surface; the resulting hadron ensemble is then propagated through a hadronic transport afterburner. A source term is included in the equations of motion to couple jets to the fluid, allowing simultaneous bulk and hard-probe evolution or, alternatively, for stopped baryons at low beam energies. The framework offers flexible choices of equations of motion (Israel-Stewart, DNMR, ADNH) and transport coefficients, along with GPU-ready performance via Kokkos/Cabana, offline equation of state inversion for 4D tables, and containerized portability. We validate the code with semi-analytical benchmarks (including BSQ Gubser and Landau-Khalatnikov solutions) and extensive convergence studies. The NuclearConfectionery provides a user-friendly, high-performance, open-source tool for event-by-event simulations across collision energies, offering flexibility to study QCD matter at both vanishing and finite densities.

nucl-th↗

arXiv2013

Decomposition of fluctuating initial conditions and flow harmonics

Collective flow observed in heavy ion collisions is largely attributed to initial geometrical fluctuations, and it is the hydrodynamic evolution of the system that transforms those initial spatial irregularities into final state momentum anisotropies. Cumulant analysis provides a mathematical tool to decompose those initial fluctuations in terms of radial and azimuthal components. It is usually thought that a specified order of azimuthal cumulant, for the most part, linearly produces flow harmonic of the same order. In this work, we carry out a systematic study on the connection between cumulants and flow harmonics using a hydrodynamic code called NeXSPheRIO. We conduct three types of calculations, by explicitly decomposing the initial conditions into components corresponding to a given eccentricity and studying the out-coming flow through hydrodynamic evolution. It is found that for initial conditions deviating significantly from Gaussian, such as those from NeXuS, the linearity between eccentricities and flow harmonics partially breaks down. Combining with the effect of coupling between cumulants of different orders, it causes the production of extra flow harmonics of higher orders. We argue that these results can be seen as a natural consequence of the non-linear nature of hydrodynamics, and they can be understood intuitively in terms of the peripheral-tube model.

hep-ph↗

arXiv2012

On the origin of trigger-angle dependence of di-hadron correlations

The STAR Collaboration reported measurements of di-hadron azimuthal correlation in medium-central Au+Au collisions at 200 A$\,$GeV, where the data are presented as a function of the trigger particle's azimuthal angle relative to the event plane $ϕ_s $. In particular, it is observed that the away-side correlation evolves from single- to double-peak structure with increasing $ϕ_s$. In this work, we present the calculated correlations as functions of both $ϕ_s$ and particle transverse momentum $p_T $, using the hydrodynamic code NeXSPheRIO. The results are found to be in reasonable agreement with the STAR data. We further argue that the above $ϕ_s$ dependence of the correlation structure can be understood in terms of one-tube model, as due to an interplay between the background elliptic flow caused by the initial state global geometry and the flow produced by fluctuations.

hep-ph↗