Nuclear Theory·nucl-th

Tuesday·May 2, 2023

9 papers—6 primary·3 cross-listed

07
Chiral symmetry restoration in a rotating medium
Irving I. Gaspar🇲🇽 · Luis A. Hernández🇲🇽 · Renato Zamora🇨🇱
We study the nature of the chiral symmetry restoration within the Yukawa model with spontaneous symmetry breaking. We work with scalar and fermion fields which are subject to the effects of a rotating system. In this work, we show the derivation of the scalar field propagator in a rotating medium using the Fock-Schwinger proper-time method. We compute analytically the effective potential in the high-temperature approximations, including the contribution of the ring diagrams to account for the plasma screening properties. We study the chiral transition as we vary the angular velocity $Ω$ , the boson self-coupling $λ$ and the fermion-boson coupling $g$ . We show that the critical temperature for the restoration of chiral symmetry always starts with decreasing behaviour, until it reaches a minimum and from there when increasing $Ω$ , we observe $T_{c}$ increases monotonically. In all the phase transition lines in the $T - Ω$ plane reported, we obtain that the rotating effects are able to change the order of the phase transition.
↳ hep-phhep-thnucl-thPRD(2023)·20 citations
08
Estimation of collision centrality in terms of the number of participating nucleons in heavy-ion collisions using deep learning
Dipankar Basak🇮🇳 · Kalyan Dey🇮🇳
The deep learning technique has been applied for the first time to investigate the possibility of centrality determination in terms of the number of participants ( $N_{part}$ ) in high-energy heavy-ion collisions. For this purpose, supervised learning using both deep neural network (DNN) and convolutional neural network (CNN) is performed with labeled data obtained by modeling relativistic heavy-ion collisions utilizing A Multi-phase Transport Model (AMPT). Event-by-event distributions of pseudorapidity and azimuthal angle of charged hadrons weighted by their transverse momentum are used as input to train the DL models. The DL models did remarkably well in predicting $N_{part}$ values with CNN slightly outperforming the DNN model. The Mean Squared Logarithmic Error (MSLE) for the CNN model (Model-4) is determined to be 0.0592 for minimum bias collisions and 0.0114 for 0-60\% centrality class, indicating that the model performs better for semi-central and central collisions. Furthermore, the studied DL model is proven to be robust to changes in energy as well as model parameters of the input. The current study demonstrates that the data-driven technique has a distinct potential for determining centrality in terms of the number of participants in high-energy heavy-ion collision experiments.
↳ hep-phnucl-thEPJA(2023)·5 citations
09
DT fusion through the $^{5}$ He $3/2 +$ "Bretscher state" accounts for $\geq 25%$ of our existence via nucleosynthesis and for the possibility of fusion energy
Mark B. Chadwick · Mark W. Paris · Brian M. Haines
In big bang nucleosynthesis (BBN), the deuterium-tritium (DT) fusion reaction, D(T,n) $α$ , enhanced by the 3/2 $^{+}$ resonance, is responsible for 99% of primordial $^{4}$ He. This has been known for decades and has been well documented in the scientific literature. However, following the tradition adopted by authors of learned articles, it was stated in a matter-of-fact manner and not emphasized; for most people, it has remained unknown. This helium became a source for the subsequent creation of $\geq$ 25% of the carbon and other heavier elements and, thus, a substantial fraction of our human bodies. (To be more precise than $\geq$ 25% will require future simulation studies on stellar nucleosynthesis.) Also, without this resonance, controlled fusion energy would be beyond reach. For example, for inertial confinement fusion (ICF), laser energy delivery for the National Ignition Facility (NIF) would have to be approximately 70 times larger for ignition. Because the resonance enhances the DT fusion cross section a hundredfold, we propose that the 3/2 $^{+}$ $^{5}$ He excited state be referred to as the "Bretscher state" in honor of the Manhattan Project scientist who discovered it, in analogy with the well-known 7.6 MeV "Hoyle state" in $^{12}$ C that allows for the resonant 3 $α$ formation.
↳ physics.hist-phastro-ph.SRnucl-exnucl-th4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Chiral symmetry restoration in a rotating medium

Estimation of collision centrality in terms of the number of participating nucleons in heavy-ion collisions using deep learning

DT fusion through the 5He 3/2+ "Bretscher state" accounts for ≥25% of our existence via nucleosynthesis and for the possibility of fusion energy

Affiliations

DT fusion through the $^{5}$ He $3/2 +$ "Bretscher state" accounts for $\geq 25%$ of our existence via nucleosynthesis and for the possibility of fusion energy