Nuclear Theory·nucl-th

Thursday·March 20, 2025

6 papers—3 primary·3 cross-listed

01
Study of event and particle selection effects on elliptic flow background at the isobar experiments based on AMPT model
Yu Wang🇨🇳 · Hua Pei🇨🇳
Measurement of the Chiral Magnetic Effect (CME) has been a popular topic of high-energy nuclear physics in the last decade. The flow correlation $γ$ between charged hadron pairs of the same and opposite charges and their difference $Δ γ$ were measured to separate the CME-driven signal from the collective flow background especially second-order elliptic $v_{2}$ . The STAR experiment have stepped further to the isobar experiment to compare $γ$ and $Δ γ$ between Ru+Ru and Zr+Zr ~\cite{PhysRevC.105.014901}, which were theoretically expected to produce the same elliptic flow background but different CME signals. However, the measured flow backgrounds also differ between Ru+Ru and Zr+Zr, indicating more fine-tuning of RP and centrality definition necessary. This analysis applied the AMPT model~\cite{PhysRevC.72.064901} to simulate the same collision system and energy as the STAR isobar experiment. Since the AMPT model does not include magnetic field effects, we expect comparing its output between Ru+Ru and Zr+Zr collision systems can provide an insight of the possible bias of flow background definition, and help improve the measurement of CME signal in real experiments. Multiple combinations of centrality and flow definition were chosen to study how the $v_{2}$ and their difference would be affected, especially by varying the particles selection of charge versus neutral properties and broadening (pseudo-)rapidity regions, while STAR CME work relied on charged-only particles at central rapidity.
nucl-thnucl-ex2 citations
02
Fine-tunings in nucleosynthesis and the emergence of life: Status and perspectives
Ulf-G. Meißner · Bernard Ch. Metsch · Helen Meyer
We discuss the fine-tunings of nuclear reactions in the Big Bang and in stars and draw some conclusions on the emergence of the light elements and the life-relevant elements carbon and oxygen. We also stress how to improve these calculations in the future. This requires a concerted effort of different communities, especially in nuclear reaction theory, lattice QCD for few-nucleon systems, stellar evolution calculations, particle physics and philosophy.
nucl-thastro-ph.SRhep-lathep-ph+1EPJA(2025)·1 citation
03
Nuclear Physics under the low-energy, high intensity frontier
C.-J. Yang · V. Horny · D. Doria · K. Spohr
Despite numerous achievements and recent progress, nuclear physics is often (wrongly) considered an old field of research nowadays. However, developments in theoretical frameworks and reliable experimental techniques have made the field mature enough to explore many new frontiers. In this regard, extending existing knowledge to an emerging field of physics -- where particles interact with a relatively low-energy but high intensity field (intense enough so that multi-particle processes become comparable or more important than one-to-one processes) -- can lead to exciting discoveries. Investigations can be realized under a highly time-compressed beam source (e.g., particle sources generated by laser-matter interaction using high-power laser systems). Here we focus on a new scheme, where high-power laser systems are exploited as a driver to generate energetic ( $γ$ -ray) photons. Together with additional low-energy photons provided by a second, less intense laser, a multi-photon absorption scheme enables a very attainable manipulation of nuclear transitions including isomer pumping and depletion.
nucl-thnucl-exProc. SPIE 13535, Research Using Extreme …·1 citation
04
Electron capture of superheavy nuclei with realistic lepton wave functions
A. Ravlić · P. Schwerdtfeger · W. Nazarewicz
The superheavy nuclei push the periodic table of the elements and the chart of the nuclides to their limits, providing a unique laboratory for studies of the electron-nucleus interactions. The most important weak decay mode in known superheavy nuclei is electron capture (EC). In the standard calculations of EC, the lepton wave functions are usually considered in the lowest-order approximation. In this work, we investigate the sensitivity of EC rates on the choice of the electron wave functions by (i) assuming the single-particle approximation for the electron wave functions, and (ii) carrying out Dirac-Hartree-Fock (DHF) calculations. The nuclear response is generated based on the state-of-the-art quasiparticle random phase approximation employing relativistic nuclear energy density functional theory. We show that using the improved lepton wave functions reduces the EC rates up to 40\% in the superheavy nucleus oganesson ( $Z = 118$ ). Interestingly, because of screening effects, the difference between the EC rates obtained with the DHF and single-particle calculations is fairly small.
↳ physics.atom-phnucl-thPRC(2025)·4 citations
05
Using Lithium and Beryllium to Study Structure and Evolution of Rotating Stars
Wuming Yang · Haibo Yuan · Yaqian Wu · Shaolan Bi · Zhijia Tian
The chemical composition of the Sun is still a highly controversial issue. No solar model has yet been able to simultaneously reproduce the solar lithium and beryllium abundances, along with helioseismic results, including the rotation profile. Lithium and beryllium are fragile elements that are highly sensitive to the physical conditions, as well as to transport and mixing processes within and below the convective zone (CZ). Uncovering the transport mechanisms responsible for the depletion of Li and Be in the Sun is crucial for using them as tools to understand stellar interiors and the associated transport and mixing processes. We constructed rotating solar models based on Magg's abundance scale, incorporating the effects of convective overshoot and magnetic fields. The rotating model exhibits superior sound speed and density profile and successfully reproduces the observed ratios $r_{02}$ and $r_{13}$ . It also matches the seismically inferred CZ depth, surface helium abundance, and rotation profile, as well as the detected Li and Be abundances and neutrino fluxes within $1 σ$ . The depletion of Li is dominated by convective overshoot and rotational mixing, while Be depletion is primarily driven by gravitational settling and rotational mixing. The presence of the tachocline accelerates Li depletion but slows down Be depletion. These distinct depletion mechanisms result in the surface abundances of Li and Be evolving differently over time.
↳ astro-ph.SRhep-exnucl-th1 citation
06
Study of hadron interactions and compositeness
Tetsuo Hyodo🇯🇵
Plenty of hadrons have been established experimentally, yet the nonperturbative nature of the strong interaction complicates a comprehensive understanding of their internal structure, particularly for exotic hadrons that extend beyond conventional mesons and baryons. One prominent candidate for the internal structure of exotic hadrons is the hadronic molecule, a loosely bound system of hadrons analogous to atomic nuclei. Understanding such systems requires precise knowledge of hadron interactions, which traditional scattering experiments struggle to provide, especially in the low-energy region. Recent advances, including precise baryon-baryon interaction measurements, femtoscopy techniques that probe momentum correlations between particles, and first-principles lattice QCD calculations, have significantly improved our understanding of hadron interactions. Here, we review these recent developments, demonstrate the successful application of femtoscopy to antikaon-nucleon interactions, utilize the concept of compositeness to quantify the hadronic molecular component of the Lambda(1405), and discuss both experimental and theoretical prospects, including future studies at J-PARC.
↳ hep-phnucl-th3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Study of event and particle selection effects on elliptic flow background at the isobar experiments based on AMPT model

Fine-tunings in nucleosynthesis and the emergence of life: Status and perspectives

Nuclear Physics under the low-energy, high intensity frontier

Electron capture of superheavy nuclei with realistic lepton wave functions

Using Lithium and Beryllium to Study Structure and Evolution of Rotating Stars

Study of hadron interactions and compositeness

Affiliations