Nuclear Physics Conference INPC2025 - TDRPA Calculations in 144,154Sm Reactions
Explore TDRPA calculations for mass and charge fluctuations in 144,154Sm reactions presented at the 29th International Nuclear Physics Conference (INPC2025). Learn about the variational principle of Balian and Vnroni, numerical implementations of TDRPA, and more in this cutting-edge research discussion. Stay informed about the latest advancements in nuclear physics.
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The 29th International Nuclear Physics Conference (INPC2025) May 25-30, 2025@Daejeon Convention Center (DCC), Daejeon, Korea 9:10-9:25 (10+5min), Room 6: 1F #103 #161 TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions This talk is based on arXiv:2504.09436 (submitted to PRC, under review) Kazuyuki Sekizawa1 in collaboration with Zepeng Gao2 Long Zhu2 1Department of Physics, School of Science, Institute of Science Tokyo 2Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University 1/8
Todays topic & our finding ? can be quantitatively described in TDRPA! Variance ?? Experimental data on 154Sm+154Sm at Ec.m.= 485 MeV 2 70 ?? 60 0 10 20 30 40 50 Mass dispersion d2? d?d?(mb/5MeV u) 500 250 Energy dissipation 450 200 TKEL (MeV) TKE (MeV) 400 150 350 100 2 ?? ?? 2 300 50 Mass dispersion 250 0 130 140 150 160 170 180 0 100 200 300 2 Variance ?? Mass number E.C. Wu, K.D. Hildenbrand, H. Freiesleben, A. Gobbi, A. Olmi, and H. Sann, Phys. Rev. Lett. 47, 1874 (1981) K.D. Hildenbrand, H. Freiesleben, A. Gobbi, U. Lynen, A. Olmi, and H. Sann, and E.C. Wu, Nucl. Phys. A405, 179 (1983) 2/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
Method: A variational principle of Balian and Vnroni (TDRPA) Variational space can be controlled by both state and observable The action-like quantity proposed by Balian and V n roni : describes the state of the system : describes the evolution of the observable in the Heisenberg picture R. Balian and M. V n roni, Phys. Rev. Lett. 47, 1353 (1981); Ann. Phys. 216, 351 (1992) C. Simenel, Phys. Rev. Lett. 106, 112501 (2011); Eur. Phys. J. A 48, 152 (2012) TDSE Unrestricted variation (w.r.t. either A or D) TDHF Slater determinant & one-body observable TDRPA Slater determinant & fluctuations of one-body observable 3/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
Numerical implementation of TDRPA for the mass width 60Ni+60Ni Forward TDHF After collision: t1 TDHF: A ~ 1.5 Experiment: A ~ 7.1 Initial state: t0 E. Williams, K. Sekizawa, D. Hinde et al., Phys. Rev. Lett. 120, 022501 (2018) 4/8
Numerical implementation of TDRPA for the mass width The Balian-V n roni prescription (TDRPA): 60Ni+60Ni Backward TDHF After collision: t1 TDHF: A ~ 1.5 Experiment: A ~ 7.1 TDRPA: A ~ 7.5 Initial state: t0 E. Williams, K. Sekizawa, D. Hinde et al., Phys. Rev. Lett. 120, 022501 (2018) 4/8
Z. Gao, K. Sekizawa, and L. Zhu, arXiv:2504.09436 Results: Mass and TKE distributions in 154Sm+154Sm at Ec.m.= 485 MeV Mass & TKE distributions agree quantitatively with the experimental data! TKE-A distribution Mass distributions for each TKE-bin 500 TKE-bins TKE (MeV) 106 187.5 12.5 MeV 450 162.5 12.5 MeV d2?/d?d? (mb/MeV u) 400 105 137.5 12.5 MeV 106 350 112.5 12.5 MeV 104 105 87.5 12.5 MeV 300 Expt. 62.5 12.5 MeV 103 250 104 37.5 12.5 MeV 102 500 TDRPA TKE (MeV) 103 450 101 400 102 100 350 10 1 101 300 250 100 10 2 130 140 150 160 170 180 Mass number ? TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions 120 130 140 150 160 170 180 Mass number ? 5/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo)
Z. Gao, K. Sekizawa, and L. Zhu, arXiv:2504.09436 2 and ?? 2 vs. TKEL in 144Sm+144Sm at Ec.m.= 500 MeV Results: Variances ?? ? Our calculations with SLy5 EDF systematically overestimate ?? ? ? TKEL vs. ?? TKEL vs. ?? TDRPA TDHF Expt. ?is overestimated in TDRPA Good agreement for ?? ?? 250 ?!! TKEL (MeV) 200 150 100 TDHF significantly underestimates the experimental data 50 0 0 20 40 60 0 100 200 ?? 300 2 2 ?? 6/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
Z. Gao, K. Sekizawa, and L. Zhu, arXiv:2504.09436 2 and ?? 2 vs. TKEL in 144Sm+144Sm at Ec.m.= 500 MeV Results: Variances ?? ? Our calculations with SLy5 EDF systematically overestimate ?? ? ? TKEL vs. ?? TKEL vs. ?? TDRPA TDHF Expt. ?is overestimated in TDRPA Good agreement for ?? ?? 250 ?!! TKEL (MeV) 200 150 Why?? 100 TDHF significantly underestimates the experimental data 50 0 0 20 40 60 0 100 200 ?? 300 2 2 ?? 6/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
Z. Gao, K. Sekizawa, and L. Zhu, arXiv:2504.09436 2 and ?? 2 vs. TKEL in 144Sm+144Sm at Ec.m.= 500 MeV Results: Variances ?? ? Our calculations with SLy5 EDF systematically overestimate ?? In TDHF & TDRPA, there is no empirical parameters other than an EDF (or an effective interaction ) A different EDF would predict different structural properties (shell structure, potential energy surface in the ?-? plane) and bulk properties (EoS, such as the symmetry energy). It may be possible to constrain EoS parameters through the experimental data on dissipative collisions of heavy nuclei at low energies around the Coulomb barrier! 7/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
If you are interested, please refer to: Z. Gao, K. Sekizawa, and L. Zhu, arXiv:2504.09436 Summary Takeaway messages Message #1 One-body dissipation in TDHF and one-body fluctuations and correlations in TDRPA play a predominant role in low-energy heavy-ion reactions. Message #2 ? in TDRPA should be related to the EDF used. The systematic overestimation of ?? This opens a new research possibility to seek for correlations between EoS parameters (e.g. the symmetry energy) and reaction outcomes (such as ?? the formers with experimental data of low-energy heavy ion reactions. ?,?? ?), and constrain Thank you for your attention! :) 8/8 Tue., May 27, 2025 K. Sekizawa (Science Tokyo) TDRPA Calculations for Mass and Charge Fluctuations and Correlations in 144,154Sm+144,154Sm Reactions
Kazuyuki Sekizawa Associate Professor Department of Physics, School of Science Institute of Science Tokyo* 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan sekizawa phys.sci.isct.ac.jp About me: https://sekizawa.fizyka.pw.edu.pl/english/ About us: https://nuclphysisct.wordpress.com/ @ See also: A white cross with a blue background Researchgate Free Icon of SuperTiny Logo, icon A red play button with a white arrow Icon Description automatically generated with low confidence Description automatically generated Description automatically generated Description automatically generated *Institute of Science Tokyo has been established after a merger of two universities, Tokyo Institute of Technology (Tokyo Tech) and Tokyo Medical and Dental University (TMDU), on October 1st, 2024.
We have implemented TDRPA in Sky3D code and performed calculations with ? = 0.8 fm, ? = 0.2 fm/c, and SLy5 EDF. Note that 144Sm (Z=62, N=82) is spherical, while 154Sm (Z=62, N=92) is of prolate shape with small octupole deformation. We put a window of experimental angular coverage (40 ?c.m. 90 ) to compare with the experimental data. Tip-on-Tip Tip-on-Side Side-on-Side
