E1 resonances in neutron-rich nuclei within the phonon damping model

Pramana

Voung Kim Au³  Akito Arima1¹  Toshio Suzuki²  Nguyen Dinh Dang1 2¹ 

[1] RI-Beam Factory Project Office, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan$$;Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550, Japan$$;Cyclotron Institute, Texas A&M University, College Station, TX 77840-3366, USA$$

关键词: Giant resonances;    giant dipole resonance;    pygmy dipole resonance.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

The quasiparticle representation of the phonon damping model (PDM) is developed to include the superfluid pairing correlations microscopically. The formalism is applied to calculate the photoabsorption and the electromagnetic (EM) differential cross sections of E1 excitations in neutron-rich oxygen and calcium isotopes. The calculated photoabsorption cross sections agree reasonably well with the available data for 16,18O and 40,48Ca. The results of calculations show that the change of the fraction of the E1 integrated strength in the region of pygmy dipole resonance (PDR) as a function of mass number 𝐴 with increasing neutron number 𝑁 is in agreement with the recent experimental data, and does not follow the prediction by the simple cluster model. The EM differential cross sections obtained within PDM in this work show prominent PDR peaks below 15 MeV for 20,22O in agreement with the recent experimental observation. It is also shown that, using low-energy RI beams at around 50-60 MeV/nucleon, one can observe clean and even enhanced PDR peaks without the admixture with the GDR in the EM differential cross sections of neutron-rich nuclei.

【 授权许可】

Unknown