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Nuclear Theory·nucl-th

Monday·January 8, 2024

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    Elastic p-12C scattering by using a cluster effective field theory

    Eun Jin In · Tae-Sun Park · Young-Ho Song · Seung-Woo Hong

    The elastic p-12C scattering at low energies is studied by using a cluster effective field theory (EFT), where the low-lying resonance states (s1/2, p3/2, d5/2) of 13N are treated as pertinent degrees of freedom. The low-energy constants of the Lagrangian are expressed in terms of the Coulomb-modified effective range parameters, which are determined to reproduce the experimental data for the differential cross-sections. The resulting theoretical predictions agree very well with the experimental data. The resulting theory is shown to give us almost identical phase shifts as obtained from the R-matrix approach. The role of the ground state of 13N below the threshold and the next-to-leading order in the EFT power counting are also discussed.

    nucl-thPRC(2024)·3 citations
  2. 02

    Nuclear mass predictions using machine learning models

    Esra Yüksel · Derya Soydaner · Hüseyin Bahtiyar

    The exploration of nuclear mass or binding energy, a fundamental property of atomic nuclei, remains at the forefront of nuclear physics research due to limitations in experimental studies and uncertainties in model calculations, particularly when moving away from the stability line. In this work, we employ two machine learning (ML) models, Support Vector Regression (SVR) and Gaussian Process Regression (GPR), to assess their performance in predicting nuclear mass excesses using available experimental data and a physics-based feature space. We also examine the extrapolation capabilities of these models using newly measured nuclei from AME2020 and by extending our calculations beyond the training and test set regions. Our results indicate that both SVR and GPR models perform quite well within the training and test regions when informed with a physics-based feature space. Furthermore, these ML models demonstrate the ability to make reasonable predictions away from the available experimental data, offering results comparable to the model calculations. Through further refinement, these models can be used as reliable and efficient ML tools for studying nuclear properties in the future.

    nucl-thPRC(2024)·39 citations
  4. 04

    Simultaneous Determination of Fragmentation Functions and Test on Momentum Sum Rule

    Jun Gao🇺🇸 · ChongYang Liu🇺🇸 · XiaoMin Shen🇺🇸 · Hongxi Xing🇨🇳 · Yuxiang Zhao🇨🇳

    We perform a simultaneous global analysis of hadron fragmentation functions (FFs) to various charged hadrons at next-to-leading order in QCD. The world data set includes results from electron-positron single-inclusive annihilation, semi-inclusive deep inelastic scattering, as well as proton-proton collisions including jet fragmentation measurements which lead to strong constraints on the gluon fragmentations. By carefully selecting hadron kinematics to ensure the validity of QCD factorization and the convergence of perturbative calculations, we achieve a satisfying best fit with d.o.f., in the simultaneous extraction of FFs for light charged hadrons (, and ). The total momentum of , quarks and gluon carried by light charged hadrons have been determined precisely. That urges future precision measurements on fragmentation to neutral hadrons, which are crucial for the test of fundamental sum rules in QCD fragmentation.

    ↳ hep-phhep-exnucl-thPRL(2024)·41 citations
  5. 05

    Chiral condensate and the equation of state at nonzero baryon density from the hadron resonance gas model with a repulsive mean field

    Deeptak Biswas🇮🇳 · Peter Petreczky🇺🇸 · Sayantan Sharma🇮🇳

    We study the QCD equation of state and the chiral condensate using the hadron resonance gas model with repulsive mean-field interactions. We find that the repulsive interactions improve the agreement with the lattice results on the derivatives of the pressure with respect to the baryon chemical potential up to eighth order. From the temperature dependence of the chiral condensate we estimate the crossover temperature as a function of baryon chemical potential, . We find that the chiral crossover line starts to deviate significantly from the chemical freeze-out line already for MeV. Furthermore, we find that the chiral pseudocritical line can be parametrized as with and , which are in agreement with lattice QCD results for small values of . For the first time we find a tiny but non-zero value of in our study.

    ↳ hep-phhep-latnucl-thPRC(2024)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE