Institute of Physics, VAST  Center for Theoretical Physics  Center for Computational Physics 
39th National Conference on Theoretical Physics (NCTP39)
Hội nghị Vật lý lý thuyết toàn quốc lần thứ 39
Buôn Ma Thuột, 2831/07/2014

ProgrammeWorkshop PresentationI.6  Invited, IWTCP2 Date: Tuesday, 29072014 Time: 16h35  17h10 Recent achievements in the study of thermal pairing and giant resonances in highly excited nucleiNguyen Dinh Dang 1) Theoretical Nuclear Physics Laboratory, Nishina Center for AcceleratorBased Science, RIKEN, 21 Hirosawa, Wako city, 3510198 Saitama, Japan; 2) Institute for Nuclear Science and Technique, Hanoi, Vietnam Recent experimental and theoretical results are presented, which show the effect of thermal pairing in highly excited nuclei. It is demonstrated that thermal pairing included in the phonon damping model (PDM) [1] is responsible for the nearly constant width of the giant dipole resonance (GDR) at low temperature T < 1 MeV [2]. It is also shown that the enhancement observed in the recent experimentally extracted nuclear level densities in 104Pd at low excitation energy and various angular momenta is the first experimental evidence of the pairing reentrance in a finite (hot rotating) nucleus [3]. In the study of GDR in highly excited nuclei, the phonon damping model (PDM) has been extended to include finite angular momenta. The results of calculations within the PDM are found in excellent agreement with the latest experimental data of GDR in the compound nucleus 88Mo [4]. Finally, an exact expression has been derived to calculate the shear viscosity $\eta$ as a function of T in finite nuclei directly from the GDR width and energy at zero and finite T. Based on this result, the values $\eta$/s of specific shear viscosity in several medium and heavy nuclei were calculated and found to decrease with increasing T to reach $(1.3  4) \times \hbar/(4\pi k_B)$ ($k_B$ is the Boltzmann constant) at T = 5 MeV, that is almost the same value obtained for quarkgluonplasma at T > 170 MeV [5]. References: [1] N. Dinh Dang and A. Arima, Phys. Rev. Lett. 80 (1998) 4145, Nucl. Phys. A 636 (1998) 427. [2] N. Dinh Dang and N. Quang Hung, Phys. Rev. C 86 (2012) 044333; B. Dey et al., Phys. Lett. B 731 (2014) 92. [3] N. Dinh Dang, N. Quang Hung, B.K. Agrawal, V.M. Datar, A. Mitra, and D.R. Chakrabarty, in preparation. [4] N. Dinh Dang, M. Ciemala, M. Kmiecik, and A. Maj, Phys. Rev. C 87 (2013) 054313. [5] N. Dinh Dang, Phys. Rev. C 84 (2011) 034309. Presenter: Nguyen Dinh Dang 
Institute of Physics, VAST

Center for Theoretical Physics 
Center for Computational Physics
© 2012 Center for Theoretical Physics & Center for Computational Physics Institute of Physics, VAST, 10 Dao Tan, Hanoi, Vietnam 