Particle production in a hybrid approach for a beam energy scan of Au+Au/Pb+Pb collisions between $$\sqrt{s_\textrm{NN}}$$ = 4.3 GeV and $$\sqrt{s_\textrm{NN}}$$ = 200.0 GeV

Abstract

Heavy-ion collisions at varying collision energies provide access to different regions of the QCD phase diagram. In particular collisions at intermediate energies are promising candidates to experimentally identify the postulated first order phase transition and critical end point. While heavy-ion collisions at low and high collision energies are theoretically well described by transport approaches and hydrodynamics+transport hybrid approaches, respectively, intermediate energy collisions remain a challenge. In this work, a modular hybrid approach, the coupling 3+1D viscous hydrodynamics () to hadronic transport (), is introduced. It is validated and subsequently applied in Au+Au/Pb+Pb collisions between $$\sqrt{s_\textrm{NN}}$$ s NN = 4.3 GeV and $$\sqrt{s_\textrm{NN}}$$ s NN = 200.0 GeV to study the rapidity and transverse mass distributions of identified particles as well as excitation functions for $$\textrm{dN}/\textrm{d}y|_{y = 0}$$ dN / d y | y = 0 and $$\langle p_\textrm{T} \rangle $$ ⟨ p T ⟩ . A good agreement with experimental measurements is obtained, including the baryon stopping dynamics. The transition from a Gaussian rapidity spectrum of protons at lower energies to the double-hump structure at high energies is reproduced. The centrality and energy dependence of charged particle $$v_2$$ v 2 is also described reasonably well. This work serves as a basis for further studies, e.g. systematic investigations of different equations of state or transport coefficients.

Collectivity in ultra-peripheral heavy-ion collisions

“…Quantitative understanding of the many-body dynamics in these small collision systems requires the development and application of full (3+1)D simulations beyond Bjorken's boostinvariance paradigm in the high energy limit [11][12][13][14][15][16][17][18]. In photon-nucleus collisions, the quasireal photon γ * 's energy fluctuates event-by-event, and is much smaller than the energy of the incoming Pb nucleus.…”

Fluctuations of conserved charges in heavy-ion collisions from a transport perspective

“…Here, a wide class of transport approaches can be used which evolve the medium until sufficient thermalization is expected. Examples of such approaches are SMASH [5], UrQMD [64], EPOS [65] or AMPT [66]. The switching criterion from transport to fluid dynamics is performed on hypersurfaces of constant proper time.…”

“…It can be measured in different ways, for a review of two different measurement techniques the reader is referred to [73]. Again, this effect will be further studied later in this work and the effects of fluctuations of conserved charge numbers will be investigated with an improved description of the model introduced in [5].…”

“…This procedure leads to the fact that conserved charges are only conserved on average and it is known, that some observables can only be described if the charges are globally conserved on the hypersurfaces. This leads to another motivation for the work in this thesis to extend the hybrid model described in [5] such that observables related to global charge conservation can be studied.…”

“…SMASH has been successfully conducted in studies for various different applications in heavy-ion collisions [95,96,97,98,99,100]. An extension of the model to describe the hot and dense stage of the heavy-ion collision using hydrodynamics has been performed in [5]. Further studies in which SMASH has been used as an afterburner can be found in [101,102].…”