Using Convolutional Neural Networks to Distinguish Nucleon Effective Mass Splitting

Li Li; Zhang Yingxun; Yang Junping; Cui Ying; Chen Xiang; Wang Xinyu; Zhao Kai

doi:10.13832/j.jnpe.2024.09.0028

Volume 46 Issue 2

Apr. 2025

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Li Li, Zhang Yingxun, Yang Junping, Cui Ying, Chen Xiang, Wang Xinyu, Zhao Kai. Using Convolutional Neural Networks to Distinguish Nucleon Effective Mass Splitting[J]. Nuclear Power Engineering, 2025, 46(2): 68-75. doi: 10.13832/j.jnpe.2024.09.0028

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Li Li, Zhang Yingxun, Yang Junping, Cui Ying, Chen Xiang, Wang Xinyu, Zhao Kai. Using Convolutional Neural Networks to Distinguish Nucleon Effective Mass Splitting[J]. Nuclear Power Engineering, 2025, 46(2): 68-75. doi: 10.13832/j.jnpe.2024.09.0028

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Using Convolutional Neural Networks to Distinguish Nucleon Effective Mass Splitting

doi: 10.13832/j.jnpe.2024.09.0028

1.
Department of Nuclear Physics, China Institute of Atomic Energy, Beijing, 102413, China
2.
Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Guilin, Guangxi, 541004, China

Received Date: 2024-10-07
Rev Recd Date: 2024-10-17

Available Online: 2025-01-23

Publish Date: 2025-04-02

Abstract

Abstract

In order to accurately distinguish the effective mass splitting of protons and neutrons in nuclear matter, a dual-channel-input convolutional neural network (CNN) is proposed for determining the effective mass splitting of nucleons. The main idea of this method is to use CNN learning theoretical model to calculate the longitudinal and transverse momentum distributions of proton and neutron yields. The theoretical model used in this study is an improved quantum molecular dynamics model (ImQMD), and the effective interaction parameters are SkM^* and SLy4, which correspond to the effective mass of neutrons being larger than the effective mass of protons and the effective mass of neutrons being smaller than the effective mass of protons respectively. Through the learning of a large number of model data, a method to distinguish the effective mass splitting of nucleons by CNN is established. The analysis of the three sets of neutron-rich target systems—⁴⁸Ca+²⁰⁸Pb, ⁴⁸Ca+¹²⁴Sn, and ¹²⁴Sn+¹²⁴Sn—shows that all three systems achieve the highest resolution accuracy at a beam energy of 50 MeV/u, exceeding 99.5%. At a beam energy of 270 MeV/u, the resolution accuracy of all three systems remains above 93%. Using the blocking method, the importance regions of the longitudinal and transverse momentum distribution of proton and neutron yields were investigated. An analysis of the importance maps for the three systems at 50 MeV/u was provided, indicating that the two-dimensional energy spectra of nucleons in the low transverse momentum region are more sensitive to the effective mass splitting of nucleons.
- Effective mass splitting of nucleons,
- Convolutional neural network (CNN),
- Neutron-rich system,
- Machine learning,
- Importance map

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References(26)

References

[1]	LI B A, CAI B J, CHEN L W, et al. Nucleon effective masses in neutron-rich matter[J]. Progress in Particle and Nuclear Physics, 2018, 99: 29-119. doi: 10.1016/j.ppnp.2018.01.001
[2]	FENG Z Q. Effective mass splitting of neutron and proton and isospin emission in heavy-ion collisions[J]. Nuclear Physics A, 2012, 878: 3-13. doi: 10.1016/j.nuclphysa.2012.01.014
[3]	ZHANG Y X, TSANG M B, LI Z X, et al. Constraints on nucleon effective mass splitting with heavy ion collisions[J]. Physics Letters B, 2014, 732: 186-190. doi: 10.1016/j.physletb.2014.03.030
[4]	COUPLAND D D S, YOUNGS M, CHAJECKI Z, et al. Probing effective nucleon masses with heavy-ion collisions[J]. Physical Review C, 2016, 94(1): 011601. doi: 10.1103/PhysRevC.94.011601
[5]	SU J, ZHU L, HUANG C Y, et al. Effects of symmetry energy and effective k-mass splitting on central ⁹⁶Ru(⁹⁶Zr)+⁹⁶Zr(⁹⁶Ru) collisions at 50 to 400 MeV/nucleon[J]. Physical Review C, 2017, 96(2): 024601. doi: 10.1103/PhysRevC.96.024601
[6]	SU J, ZHU L, GUO C C. Constraints on the effective mass splitting by the isoscalar giant quadrupole resonance[J]. Physical Review C, 2020, 101(4): 044606. doi: 10.1103/PhysRevC.101.044606
[7]	ZHANG F, SU J. Probing neutron–proton effective mass splitting using nuclear stopping and isospin mix in heavy-ion collisions in GeV energy region[J] Nuclear Science and Techniques, 2022, 31(8): 77.
[8]	LI B A, CAI B J, XIE W J, et al. Progress in constraining nuclear symmetry energy using neutron star observables since GW170817[J]. Universe, 2021, 7(6): 182. doi: 10.3390/universe7060182
[9]	STEIGMAN G. Primordial nucleosynthesis: successes and challenges[J] International Journal of Modern Physics E, 2006, 15(1): 1-35.
[10]	MEIßNER U G, RAKHIMOV A M, WIRZBA A, et al. Neutron-proton mass difference in isospin-asymmetric nuclear matter[J]. The European Physical Journal A, 2007, 32(3): 299-309. doi: 10.1140/epja/i2007-10390-9
[11]	LI A, HU J N, SHANG X L, et al. Nonrelativistic nucleon effective masses in nuclear matter: Brueckner-Hartree-Fock model versus relativistic Hartree-Fock model[J]. Physical Review C, 2016, 93(1): 015803. doi: 10.1103/PhysRevC.93.015803
[12]	SHANG X L, LI A, MIAO Z Q, et al. Nucleon effective mass in hot dense matter[J]. Physical Review C, 2020, 101(6): 065801. doi: 10.1103/PhysRevC.101.065801
[13]	OU L, LI Z X, ZHANG Y X, et al. Effect of the splitting of the neutron and proton effective masses on the nuclear symmetry energy at finite temperatures[J]. Physics Letters B, 2011, 697(3): 246-250. doi: 10.1016/j.physletb.2011.01.062
[14]	VAN DALEN E N E, MÜTHER H. Off-shell behavior of nucleon self-energy in asymmetric nuclear matter[J]. Physical Review C, 2010, 82(1): 014319. doi: 10.1103/PhysRevC.82.014319
[15]	WANG S B, TONG H, ZHAO Q, et al. Neutron-proton effective mass splitting in neutron-rich matter[J]. Physical Review C, 2023, 108(3): L031303. doi: 10.1103/PhysRevC.108.L031303
[16]	ZUO W, CAO L G, LI B A, et al. Isospin splitting of the nucleon mean field[J]. Physical Review C, 2005, 72(1): 014005. doi: 10.1103/PhysRevC.72.014005
[17]	MANSOUR H, GAD K, HASSANEEN K S A. Self-consistent green function calculations for isospin asymmetric nuclear matter[J]. Progress of Theoretical Physics, 2010, 123(4): 687-700. doi: 10.1143/PTP.123.687
[18]	MARGUERON J, CASALI R H, GULMINELLI F. Equation of state for dense nucleonic matter from metamodeling. I. Foundational aspects[J]. Physical Review C, 2018, 97(2): 025805. doi: 10.1103/PhysRevC.97.025805
[19]	LI X H, GUO W J, LI B A, et al. Neutron–proton effective mass splitting in neutron-rich matter at normal density from analyzing nucleon–nucleus scattering data within an isospin dependent optical model[J]. Physics Letters B, 2015, 743: 408-414. doi: 10.1016/j.physletb.2015.03.005
[20]	ZHANG Z, CHEN L W. Isospin splitting of the nucleon effective mass from giant resonances in ²⁰⁸Pb[J]. Physical Review C, 2016, 93(3): 034335. doi: 10.1103/PhysRevC.93.034335
[21]	XU J, XIE W J, LI B A. Bayesian inference of nuclear symmetry energy from measured and imagined neutron skin thickness in ^{116, 118, 120, 122, 124, 130, 132}Sn, ²⁰⁸Pb and ⁴⁸Ca[J]. Physical Review C, 2020, 102(4): 044316. doi: 10.1103/PhysRevC.102.044316
[22]	MORFOUACE P, TSANG C Y, ZHANG Y, et al. Constraining the symmetry energy with heavy-ion collisions and Bayesian analyses[J]. Physics Letters B, 2019, 799: 135045. doi: 10.1016/j.physletb.2019.135045
[23]	TSANG C Y, KURATA-NISHIMURA K, TSANG M B, et al. Constraining nucleon effective masses with flow and stopping observables from the SπRIT experiment[J]. Physics Letters B, 2024, 853: 138661. doi: 10.1016/j.physletb.2024.138661
[24]	ZHANG Y X, WANG N, LI Q F, et al. Progress of quantum molecular dynamics model and its applications in heavy ion collisions[J]. Frontiers of Physics, 2020, 15(5): 54301. doi: 10.1007/s11467-020-0961-9
[25]	SAGAWA H, YOSHIDA S, ZENG G M, et al. Isospin dependence of incompressibility in relativistic and nonrelativistic mean field calculations[J]. Physical Review C, 2007, 76(3): 034327. doi: 10.1103/PhysRevC.76.034327
[26]	邢凤竹,崔建坡,高永浩,等. 超重核²⁹⁶Og的结构和α衰变[J]. 原子核物理评论,2023, 40(4): 511-518.