12-14 March 2018
TIFR, Mumbai
Asia/Kolkata timezone
FIG 2018
Home > Timetable > Contribution details
PDF | XML

Coupling between two extreme excitation mode in weakly deformed 142Eu

Presented by Mr. Sajad ALI
Type: Poster

Content

Spectroscopic investigation of weakly deformed nuclei in mass A ∼ 140 region has generated considerable interest as they exhibit varieties of excitation mechanisms at higher excitation energy. The multi-particle configuration along with its small deformation plays an important role at higher excitation energy resulting in several novel phenomena, like shears mechanism, octupole correlation, chiral symmetry breaking etc. Among these magnetic rotation (MR) is a well known phenomena for generating angular momentum in weakly deformed nuclei manifested in a regular sequence of rotational-like bands consisting of stretched dipole transitions (M1). On the other hand breaking of reflection symmetry results octupole moment is also an important feature. The interaction between the orbitals of near the Fermi surface which differ by three units of angular momenta, leading to a sequence of interleaved states of opposite parity. Typically, this situation occurs when Fermi level is found between intruder sub-shell (l, j) and normal parity sub-shell (l − 3, j − 3) [1]. The dynamical correlation between this sub-shell resulted in enhanced E1 transitions between the sequences of interleaved states of negative and positive parity. For weakly deformed nuclei in A ∼ 140 region protons can be easily excited to the h_11/2 orbital across the Z = 64 sub-shell closure. The interaction between d_5/2 and h_11/2 orbitals of the proton sector near the Fermi surface may leads the band of interleaved states of negative and positive parity connected by E1 transitions. Also, due to the presence of particles and holes in high j orbitals MR band can also be observed. This opens up the possibility of observing two extreme mode of excitation in the vicinity of Z = 64 sub-shell closure. In order to investigate these possibilities 142Eu is populated through the reaction 31P(116Cd, 5n) at E_lab = 148-MeV at TIFR, Mumbai with INGA as a detection system. In 142 Eu a negative parity dipole band starting from 13^− to 21^− connected to the positive parity dipole band by three E1 transition reported earlier [2]. In the reported work, more connecting E1 transitions and cross over E2 transitions are placed. Along with the transition strength (B(M1), B(E1) and B(E2)) are evaluated from the lifetime measurement of the states of the negative parity dipole band. B(M 1) value shows decreasing nature with spin characteristics of MR band. The large B(E1) value of the connecting transition and the ratio B(E1)/B(E2) values may be understood as a result of octupole correlation. This observation also leads to the unique observation of coupling between two extreme mode of generation of angular momentum i.e. shears mechanism and octupole correlation in a single nuclei. References: [1] P.A. Butler, W. Nazarewicz, Rev. Mod. Phys. 68, 349 (1996). [2] M. Piiparinen et al., Nucl. Phys. A 605, 191 - 268 (1996).

Place

Location: TIFR, Mumbai
Room: AG66

Primary authors

More

Co-authors

  • Ms. Prithwijita RAY Saha Institute of Nuclear Physics, HBNI, Kolkata 700064, India
  • Dr. Haridas PAI Saha Institute of Nuclear Physics, HBNI, Kolkata 700064, India
  • Dr. Rajarshi RAUT UGC-DAE-Consortium for Scientific Research, Kolkata 700098, India
  • Dr. Abhijit BISOI Indian Institute of Engineering Science and Technology, Howrah 711103, India
More