A chiral mean-field equation-of-state in UrQMD: effects on the heavy ion compression stage

Kuttan, Manjunath Omana; Motornenko, Anton; Steinheimer, Jan; Stoecker, Horst; Nara, Yasushi; Bleicher, Marcus

doi:10.1140/epjc/s10052-022-10400-2

Cited by 15 publications

(19 citation statements)

References 65 publications

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“…a chiral mean field EoS can also be introduced, see e.g. [31]. In its current version, UrQMD includes a large body of baryonic and mesonic resonances up to masses of 4 GeV.…”

Section: Model Setup and Flow Extractionmentioning

confidence: 99%

Harmonic flow correlations in Au+Au reactions at 1.23 AGeV: a new testing ground for the equation-of-state and expansion geometry

et al. 2022

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Correlations between the harmonic flow coefficients $$v_1$$ v 1 , $$v_2$$ v 2 , $$v_3$$ v 3 and $$v_4$$ v 4 of nucleons in semi-peripheral Au+Au collisions at a beam energy of 1.23 AGeV are investigated within the hadronic transport approach ultra-relativistic quantum molecular dynamics (UrQMD). In contrast to ultra-relativistic collision energies (where the flow coefficients are evaluated with respect to the respective event plane), we predict strong correlations between the flow harmonics with respect to the reaction plane. Based on an event-by-event selection of the midrapidity final state elliptic flow of nucleons we show that as a function of rapidity, (I) the sign of the triangular flow changes, (II) that the shape of $$v_4$$ v 4 changes from convex to concave, and (III) that $$v_3\propto v_1v_2$$ v 3 ∝ v 1 v 2 and $$v_4\propto v_2^2$$ v 4 ∝ v 2 2 for all different event classes, indicating strong correlations between all investigated harmonic flow coefficients.

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“…a chiral mean field EoS can also be introduced, see e.g. [31]. In its current version, UrQMD includes a large body of baryonic and mesonic resonances up to masses of 4 GeV.…”

Section: Model Setup and Flow Extractionmentioning

confidence: 99%

Harmonic flow correlations in Au+Au reactions at 1.23 AGeV: a new testing ground for the equation-of-state and expansion geometry

et al. 2022

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“…Since presently rather precise constraints on the incompressibility are known, the Skyrme potential is essentially without any degree of freedom. To be able to study the EoS for densities far above nuclear saturation, it would be beneficial to extend the potential beyond a simple two-term Skyrme prescription (see also, e.g., [27,59,60] for a discussion and another possible way to extend the EoS).…”

Section: The Skyrme Modelmentioning

confidence: 99%

“…This is because at lower energies, the approach to equilibration, necessary for the initial state used in the fluid dynamic approaches, takes an ever increasing fraction of the duration of the collision. Moreover, the role of the EoS during the compression phase is not addressed in hybrid models, and it has been shown to have a strong impact on the extracted observables [26,27].…”

Section: Introductionmentioning

confidence: 99%

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The high-density equation of state in heavy-ion collisions: constraints from proton flow

et al. 2022

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A set of different equations of state is implemented in the molecular dynamics part of a non-equilibrium transport simulation (UrQMD) of heavy-ion collisions. It is shown how different flow observables are affected by the density dependence of the equation of state. In particular, the effects of a phase transition at high density are explored, including an expected reduction in mean $$m_T$$ m T . We also show that an increase in $$v_2$$ v 2 is characteristic for a strong softening of the equation of state. The phase transitions with a low coexistence density, $$n_{\text {CE}}<4 n_0$$ n CE < 4 n 0 , show a distinct minimum in the slope of the directed flow as a function of the beam energy, which would be a clear experimental signal. By comparing our results with experimental data, we can exclude any strong phase transition at densities below $$4n_0$$ 4 n 0 .

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“…The smooth nature of the crossover from hadrons to quarks does not lead to a third family branch of compact stars. All these components allow the CMF model to be applied for modeling of heavy-ion collisions (Steinheimer et al 2010;Omana Kuttan et al 2022), analysis of lattice QCD data , 2014Motornenko et al 2020Motornenko et al , 2021aMotornenko et al 2021b), as well as studies of cold neutron stars and their mergers (Most et al 2022). Since the CMF EoS does not include heavy nuclei at sub-saturation density, we extend it to low densities using the SFHx EoS (Steiner et al 2013), which is matched to the CMF table at densities less than 8 × 10 13 g cm −3 .…”

Section: Cmf Eosmentioning

confidence: 99%

The Role of the Hadron-Quark Phase Transition in Core-Collapse Supernovae

Jakobus,

Mueller,

Heger

et al. 2022

Preprint

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The hadron-quark phase transition in quantum chromodyanmics has been suggested as an alternative explosion mechanism for core-collapse supernovae. We study the impact of three different hadron-quark equations of state (EoS) with first-order (DD2F, STOF-B145) and second-order (CMF) phase transitions on supernova dynamics by performing 97 simulations for solarand zero-metallicity progenitors in the range of 14-100 M . We find explosions only for two low-compactness models (14M and 16 M ) with the DD2F EoS, both with low explosion energies of ∼10 50 erg. These weak explosions are characterised by a neutrino signal with several mini-bursts in the explosion phase due to complex reverse shock dynamics, in addition to the typical second neutrino burst for phase-transition driven explosions. The nucleosynthesis shows significant overproduction of nuclei such as 90 Zr for the 14 M zero-metallicity model and 94 Zr for the 16 M solar-metallicity model, but the overproduction factors are not large enough to place constraints on the occurrence of such explosions. Several other low-compactness models using the DD2F EoS and two high-compactness models using the STOS EoS end up as failed explosions and emit a second neutrino burst. For the CMF EoS, the phase transition never leads to a second bounce and explosion. For all three EoS, inverted convection occurs deep in the core of the proto-compact star due to anomalous behaviour of thermodynamic derivatives in the mixed phase, which heats the core to entropies up to 4𝑘 B /baryon and may have a distinctive gravitational wave signature, also for a second-order phase transition.

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A chiral mean-field equation-of-state in UrQMD: effects on the heavy ion compression stage

Abstract: It is shown that the initial compression in central heavy ion collisions at beam energies of $$E_{\mathrm {lab}}=1-10A$$ E lab = 1 - 10 A GeV depends dominantly on the underlying equation of state and only marginally on the model used for the dynamical description. To do so… Show more

Cited by 15 publications

References 65 publications

Harmonic flow correlations in Au+Au reactions at 1.23 AGeV: a new testing ground for the equation-of-state and expansion geometry

Harmonic flow correlations in Au+Au reactions at 1.23 AGeV: a new testing ground for the equation-of-state and expansion geometry

The high-density equation of state in heavy-ion collisions: constraints from proton flow

The Role of the Hadron-Quark Phase Transition in Core-Collapse Supernovae

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