Universität zu Köln

Spieker, M., Petkov, P., Litvinova, E., Mueller-Gatermann, C., Pickstone, S. G., Prill, S., Scholz, P. and Zilges, A. (2018). Shape coexistence and collective low-spin states in Sn-112,Sn-114 studied with the (p,p'y) Doppler-shift attenuation coincidence technique. Phys. Rev. C, 97 (5). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9993

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Abstract

Background: The semimagic Sn (Z = 50) isotopes have been subject to many nuclear-structure studies. Signatures of shape coexistence have been observed and attributed to two-proton-two-hole (2p-2h) excitations across the Z = 50 shell closure. In addition, many low-lying nuclear-structure features have been observed which have effectively constrained theoretical models in the past. One example are so-called quadrupole-octupole coupled states (QOC) caused by the coupling of the collective quadrupole and octupole phonons. Purpose: Proton-scattering experiments followed by the coincident spectroscopy of gamma rays have been performed at the Institute for Nuclear Physics of the University of Cologne to excite low-spin states in Sn-112 and Sn-114 to determine their lifetimes and extract reduced transition strengths B(Pi L) Methods: The combined spectroscopy setup SONIC@HORUS has been used to detect the scattered protons and the emitted y rays of excited states in coincidence. The novel (p,p'gamma) Doppler-shift attenuation (DSA) coincidence technique was employed to measure sub-ps nuclear level lifetimes. Results: Seventy-four (74) level lifetimes tau of states with J = 0-6 were determined. In addition, branching ratios were deduced which allowed the investigation of the intruder configuration in both nuclei. Here, sd IBM-2 mixing calculations were added which support the coexistence of the two configurations. Furthermore, members of the expected QOC quintuplet are proposed in Sn-114 for the first time. The 1(-) candidate in Sn-114 fits perfectly into the systematics observed for the other stable Sn isotopes. Conclusions: The E2 transition strengths observed for the low-spin members of the so-called intruder band support the existence of shape coexistence in Sn-112,Sn-114. The collectivity in this configuration is comparable to the one observed in the Pd nuclei, i.e., the 0p-4h nuclei. Strong mixing between the 0(+) states of the normal and intruder configuration might be observed in Sn-114. The general existence of QOC states in Sn-112,Sn-114 is supported by the observation of QOC candidates with J not equal 1.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Spieker, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Petkov, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Litvinova, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller-Gatermann, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pickstone, S. G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Prill, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scholz, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zilges, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-186368
DOI:	10.1103/PhysRevC.97.054319
Journal or Publication Title:	Phys. Rev. C
Volume:	97
Number:	5
Date:	2018
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9993
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INTRUDER BANDS; GAMMA-RAY; EVEN; SPECTROSCOPY; EXCITATIONS; ISOTOPES; PROGRAM; NUCLEI; SN-114 Multiple languages Physics, Nuclear Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/18636