Nuclear Theory·nucl-th

Tuesday·September 26, 2023

10 papers—6 primary·4 cross-listed

07
Investigating nonflow contribution subtraction in d-Au collisions with AMPT model
Zuman Zhang🇨🇳 · Sha Li🇨🇳 · Ning Yu🇨🇳 · Qiao Wu🇨🇳
This paper presents research that focuses on nonflow contribution subtraction in heavy-ion collisions, using a multiphase transport model (AMPT). Specifically, the study aims to investigate the behavior of charged particle elliptic flow ( $v_{2}$ ) in d-Au collisions at a collision energy of $s_{NN} = 200$ GeV and to determine the impact of nonflow sources, such as jet correlations and resonance decays, in small collision systems. To reduce nonflow effects, the per-trigger yield distribution in peripheral d-Au collisions or pp collisions with the same collision energy is subtracted. Our results show that the nonflow effects in central and mid-central collisions are not strongly dependent on subtracting the per-trigger yield distribution in peripheral d-Au collisions or pp collisions. Furthermore, the elliptic flow of charged particles, after removing nonflow effects through two subtracting methods from this work, exhibits consistency in various collision centrality classes. We also discuss comparisons with measurements from d-Au collisions at $s_{NN} = 200$ GeV. Overall, this work provides valuable insights and serves as a reference for researchers studying nonflow contribution subtraction in experiments with small collision systems.
↳ nucl-exnucl-thEPJA(2023)·3 citations
08
Bubble nucleation in the two-flavor quark-meson model
Junrong Wang🇨🇳 · Ziwan Yu🇨🇳 · Hong Mao🇨🇳
We investigate the dynamics of a first-order quark-hadron transition via homogeneous thermal nucleation in the two-flavor quark-meson model. The contribution of the fermionic vacuum loop in the effective thermodynamics potential and phase diagram together with the location of critical end point (CEP) have been obtained in the temperature and chemical potential plane. For a weak and strong first-order phase transition, by taking the temperature as a variable, the critical bubble profiles, the evolutions of the surface tension and the saddle-point action in the presence of a nucleation bubble are numerically calculated in detail when fixing the chemical potentials at $μ = 306 MeV$ and $μ = 309 MeV$ . Our results show that the system could be trapped in the metastable state for a long time as long as the temperature is between the metastable region characterized by the up and low spinodal lines. Moreover, the surface tension at criticality will rise up to about $4 MeV/f m^{2}$ when the chemical potential is very high. Such a small value of the surface tension would favor a mixed phase in the cores of compact stars and may have an important implication in astrophysics.
↳ hep-phnucl-thCPC(2024)·7 citations
09
A New Model for Jet Energy Loss in Heavy Ion Collisions
Alexander Lind🇫🇷 · Iurii Karpenko🇫🇷 · Martin Rohrmoser🇵🇱 · Joerg Aichelin🇫🇷 · Pol Gossiaux🇫🇷 · Klaus Werner🇫🇷
We present a new model for jet quenching from coherent radiation in a brick medium. The jet energy loss is simulated as a perturbative final-state vacuum parton shower followed by a medium-induced shower originating from elastic and radiative collisions with the medium constituents. Coherency is achieved by starting with trial gluons that act as field dressing of the initial jet parton. These are formed according to a Gunion-Bertsch seed. The QCD version of the LPM effect is attained by increasing the phase of the trial gluons through elastic scatterings with the medium. Above a phase threshold, the trial gluons will be realised and can produce coherent radiation themselves. The model has been implemented in a Monte Carlo code and has been validated by successfully reproducing the BDMPS-Z prediction for the energy spectrum. The realistic case with minimal assumptions are also produced and shown. In particular, we show the influence of various parameters on the energy spectrum and transverse momentum distribution, such as the in-medium quark masses, the energy transfer in the recoil process, and the phase accumulation criteria, especially for low and intermediate energy gluons. Future studies will allow for the interface with full simulations of the quark-gluon-plasma with hydrodynamic evolution, such as vHLLE, along with subsequent hadronisation of the jet partons in order to produce realistic distributions that can be directly compared to LHC and RHIC data.
↳ hep-phnucl-thPoS(2024)·0 citations
10
High precision measurement of the $^{99}$ Tc $β$ spectrum
Michael Paulsen🇩🇪 · Philipp Ranitzsch🇩🇪 · Martin Loidl🇫🇷 · Matias Rodrigues🇫🇷 · Karsten Kossert🇩🇪 · Xavier Mougeot🇫🇷 · Abilasha Singh🇫🇷 · Sylvain Leblond🇫🇷 · Jörn Beyer🇩🇪 · Lina Bockhorn🇩🇪 · Christian Enss🇩🇪 · Mathias Wegner · Sebastian Kempf · Ole Nähle🇩🇪
Highly precise measurements of the $^{99}$ Tc beta spectrum were performed in two laboratories using metallic magnetic calorimeters. Independent sample preparations, evaluation methods and analyses yield consistent results and the spectrum could be measured down to less than 1 keV. Consistent beta spectra were also obtained via cross-evaluations of the experimental data sets. An additional independent measurement with silicon detectors in a $4 π$ configuration confirms the spectrum shape above 25 keV. Detailed theoretical calculations were performed including nuclear structure and atomic effects. The spectrum shape was found to be sensitive to the effective value of the axial-vector coupling constant. Combining measurements and predictions, we extracted $Q_{β} =$ 295.82(16) keV and $g_{A}^{eff} = 1.530 (83)$ . Furthermore, we derived the mean energy of the beta spectrum $E_{β}$ =98.45(20) keV, $lo g f = - 0.47660 (22)$ and $lo g f t = 12.3478 (23)$ .
↳ nucl-exnucl-thphysics.ins-detPRC(2024)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE

Investigating nonflow contribution subtraction in d-Au collisions with AMPT model

Bubble nucleation in the two-flavor quark-meson model

A New Model for Jet Energy Loss in Heavy Ion Collisions

High precision measurement of the 99Tc β spectrum

Affiliations

High precision measurement of the $^{99}$ Tc $β$ spectrum