The lifetimes of low-lying excited states below the <math altimg='si1.svg'><msup><mrow><mn>8</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> seniority isomer were directly measured using fast timing detectors in the neutron-deficient isotopes 98,100Cd. This experiment was conducted with the DEcay SPECtroscopy (DESPEC) setup at GSI, where the ions of interest were produced via a fragmentation reaction and identified using the FRagment Separator (FRS) before being implanted in the AIDA active stopper system, and the <italic>&#947;</italic> rays emitted during the de-excitation of isomeric states were detected by the LaBr <inf>3</inf> FATIMA Array. The newly deduced values for the reduced transition probabilities were compared with shell-model calculations using different interactions and effective charges. The results indicate that, while 98Cd aligns well with a seniority scheme description, in 100Cd the transition strengths among low-lying states are not fully reproduced, and the nature of these states remains an open problem within the present theoretical description. Ultimately, a key element in the description of this region, crucial for nuclear physics and astrophysics, appears to be the proton-neutron term of the nuclear effective interaction.

China

Italy

G. Zhang

M. Polettini

D. Mengoni

G. Benzoni

Z. Huang

Germany

M. Górska

A. Blazhev

Spain

L.M. Fraile

A. Gargano

G. De Gregorio

France

F. Nowacki

G. Aggez

U. Ahmed

Sweden

O. Aktas

Saudi Arabia

M. Al-Aqeel

United Kingdom

B. Alayed

H.M. Albers

A. Algora

S. Alhomaidhi

F. Amjad

C. Appleton

T. Arıcı

M. Armstrong

B.Q. Arnés

A. Astier

M. Balogh

A. Banerjee

D. Bazzacco

J. Benito Garcìa

S. Bottoni

P. Boutachkov

A. Bracco

A. Bruce

D. Brugnara

C. Bruno

F. Camera

B. Cederwall

M. Cicerchia

M.M.R. Chishti

A. Corsi

M.L. Cortes

D. Cox

F.C.L. Crespi

B. Das

T. Davidson

G. de Angelis

T. Dickel

M. Doncel

A. Ertoprak

A. Esmaylzadeh

L. Gaffney

F. Galtarossa

E.R. Gamba

J. Garbe

D. Genna

J. Gerl

A. Goasduff

A. Gottardo

A. Gozzelino

Finland

T. Grahn

J. Ha

E. Haettner

O. Hall

L. Harkness-Brennan

H. Heggen

C. Hornung

Y. Hrabar

S.P. Hu

N. Hubbard

K.E. Ide

A. Illana

S. Jazrawi

P.R. John

J. Jolie

C. Jones

D. Joss

D. Judson

V. Karayonchev

E. Kazantseva

R. Kern

Hungary

G.G. Kiss

L. Knafla

R. Knöbel

I. Kojouharov

Poland

A. Korgul

W. Korten

P. Koseoglou

D. Kostyleva

T. Kurtukian-Nieto

Slovenia

G. Kosir

N. Kurz

I. Kuti

M. Labiche

S.M. Lenzi

S. Leoni

G.S. Li

Z. Liu

M. Llanos Expósito

R. Lozeva

J.B. Lu

Approaching 100Sn: Structural evolution in 98,100Cd via lifetime measurements

The neutron-rich rare isotope $^{190}$W is discussed as a candidate for a prolate-oblate transitional nucleus with maximum γ-softness. The collectivity of this isotope is assessed for the first time by the measurement of the reduced E2 transition probability of its first <math><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></math> state to the ground state. The experiment employed the FAst TIming Array (FATIMA), comprised of 36 LaBr$_{3}$(Ce) scintillators, which was part of the DESPEC setup at GSI, Darmstadt. The <math><msubsup><mrow><mn>4</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup></math> and <math><msubsup><mrow><mn>2</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup></math> states of $^{190}$W were populated subsequently to the decay of its 127(12) μs isomeric <math><msup><mrow><mi>J</mi></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo></mrow></msup></math> state. The mean lifetime of the <math><msubsup><mrow><mn>2</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup></math> state was determined to be <math><mi>τ</mi><mo>=</mo><mn>274</mn><mo>(</mo><mn>28</mn><mo>)</mo></math> ps, which corresponds to a <math><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mrow><mn>2</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup><mo>→</mo><msubsup><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup><mo>)</mo></math> value of 95(10) W.u. The results motivated a revision of previous calculations within an energy-density functional-based interacting boson model-2 approach, yielding E2 transition properties and spectroscopic quadrupole moments for tungsten isotopes. From comparison to theory, the new data suggest that $^{190}$W is at the transition from prolate to oblate structure along the W isotopic chain, which had previously been discussed as a nuclear shape-phase transition.

E. Şahin

V. Werner

A.K. Mistry

M. Rudigier

Japan

K. Nomura

N. Pietralla

P.H. Regan

Türkiye

G. Ağgez

Ö. Aktaş

J. Benito

A.M. Bruce

M.L. Cortés

F. Crespi

T. Davinson

C.E. Jones

N. Kuzminchuk

M. Llanos-Expósito

Greece

T.J. Mertzimekis

M. Mikolajczuk

A.I. Morales

I. Mukha

J.R. Murias

B.S. Nara-Singh

S.E.A. Orrigo

J. Pellumaj

Belgium

S. Pelonis

S. Pietri

S. Pigliapoco

Zs. Podolyák

K. Rezynkina

H.A. Rösch

H. Schaffner

Ch. Scheidenberger

L. Sexton

Romania

P.A. Söderström

Y.K. Tanaka

J.J. Valiente-Dobón

P. Vasileiou

J. Vasiljević

J. Vesic

H. Weick

J. Wiederhold

A. Yaneva

J. Zhao

A. Zyriliou

Collectivity at the prolate-oblate transition: The Lifetime of W

The nucleus 212Po has been produced through the fragmentation of a 238U primary beam at 1 GeV/nucleon at GSI, separated with the FRagment Separator, FRS, and studied via isomer <italic>&#947;</italic>-decay spectroscopy with the RISING setup. Two delayed previously unknown <italic>&#947;</italic> rays have been observed. One has been attributed to the E3 decay of a 21 &#8722; isomeric state feeding the <italic>&#945;</italic>-emitting 45-s (18 +) high-spin isomer. The other <italic>&#947;</italic>-ray line has been assigned to the decay of a higher-lying 23 + metastable state. These are the first observations of high-spin states above the 212Po (18 +) isomer, by virtue of the selectivity obtained via ion-by-ion identification of 238U fragmentation products. Comparison with shell-model calculations points to shortfalls in the nuclear interactions involving high- <italic>j</italic> proton and neutron orbitals, to which the region around <italic>Z</italic>&#8764;100 is sensitive.

L. Zago

A. Gadea

S. Lunardi

D. Rudolph

J. Benlliure

E. Casarejos

C. Domingo-Pardo

T. Engert

H. Geissel

N. Goel

J. Grebosz

E. Gregor

T. Habermann

S. Klupp

India

S. Mandal

R. Menegazzo

B. Million

D.R. Napoli

F. Naqvi

C. Nociforo

M. Pfützner

A. Prochazka

F. Recchia

E. Sahin

A. Sharma

Slovakia

B. Sitar

D. Siwal

P. Strmen

I. Szarka

C.A. Ur

P.M. Walker

O. Wieland

High-spin states in 212Po above the <italic>&#945;</italic>-decaying (18 +) isomer