A Magnetic Rotational (MR) band in 57Fe nucleus has been newly identified and established from the decreasing behaviour of the experimental electric dipole transition probabilities, B(M1), determined from the measured lifetimes of the states. This becomes the first nucleus in the lighter mass ( <math altimg='si1.svg'><mi>A</mi><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>60</mn></math>) region in which, the B(M1) values of an MR band are measured. A single-particle configuration of <math altimg='si2.svg'><mi>&#960;</mi><msubsup><mrow><mi>f</mi></mrow><mrow><mn>7</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn></mrow></msubsup><mo>&#8855;</mo><mi>&#957;</mi><msup><mrow><mo stretchy='false'>(</mo><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow></msub><msub><mrow><mi>f</mi></mrow><mrow><mn>5</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow></msub><msub><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow></msub><mo stretchy='false'>)</mo></mrow><mrow><mn>3</mn></mrow></msup></math> has been assigned to this MR band. This configuration, which involves only the negative parity proton and neutron orbitals below and above the Z,N = 28 shell closures, respectively, is a unique one which was not identified before for an MR band. The range of observed angular momenta for this band is congruent with this configuration and the experimental data are found to be in agreement with the SPAC (Shears mechanism with Principal Axis Cranking) and semi-classical calculations. Shell model calculations with GXPF1A interaction reproduce the observed levels in 57Fe including the band head of the MR band. This validates the assigned configurations of this band.

India

S. Basu

G. Mukherjee

S. Rajbanshi

Japan

Y. Utsuno

Noritaka Shimizu

France

S. Nandi

S.S. Nayak

S. Pal

S. Bhattacharyya

S. Chakraborty

Soumik Bhattacharya

Shabir Dar

Sneha Das

S. Basak

D. Kumar

D. Paul

K. Banerjee

Pratap Roy

S. Manna

Samir Kundu

T.K. Rana

R. Pandey

S. Samanta

S. Chatterjee

R. Raut

S.S. Ghugre

Romania

H. Pai

A. Karmakar

S. Chattopadhyay

S. Das Gupta

P. Pallav

R. Banik

S. Ali

China

Y.M. Wang

Q.B. Chen

Conclusive evidence of magnetic rotational band in 57Fe: Extending the shears mechanism to the fp shell orbital

The potential presence of wobbling motions in even-even nuclei $^{112}$Ru, $^{114}$Pd, $^{150}$Nd, and $^{188}$Os are explored by the five-dimensional collective Hamiltonian based on the relativistic density functional theory (5DCH-RDFT). The theoretical results successfully reproduce experimental energy spectra and electromagnetic transition probabilities. Analyses of the potential energy surfaces and probability density distributions in the <math><mo>(</mo><mi>β</mi><mo>,</mo><mi>γ</mi><mo>)</mo></math> deformation plane as well as the quadrupole asymmetry parameter <math><mo>〈</mo><mi>cos</mi><mo>⁡</mo><mn>3</mn><mi>δ</mi><mo>〉</mo></math> reveal that $^{150}$Nd shows near-axial symmetry in contrast to the triaxial deformation in $^{112}$Ru, $^{114}$Pd, and $^{188}$Os. Additionally, spin coherent state (SCS) map is introduced for the first time to the 5DCH framework to visualize the geometry of angular momentum. It is revealed that the wobbling mode, characterized by oscillations of total angular momentum J about the medium axis, is present in $^{112}$Ru but absent in $^{150}$Nd.

Exploring wobbling motion in triaxial even-even nuclei

Two new negative-parity bands have been identified in the odd-odd $^{104}$Rh nucleus. According to their experimentally observed properties, they have the same <math><mi>π</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>⊗</mo><mi>ν</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mn>1</mn></mrow></msup></math> high-j configuration as the previously known negative-parity chiral doublet bands. This observation raises the possibility of the existence of multiple chiral doublet bands, MχD, in this nucleus. Comparing the properties of the observed bands with results of detailed theoretical calculations, one can conclude that the lower energy parts of bands 1 and 2 are chiral partner bands with the <math><mi>π</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>⊗</mo><mi>ν</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mn>1</mn></mrow></msup></math> two-quasiparticle configuration, while bands 3 and 4 are chiral partner bands with the <math><mi>π</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>⊗</mo><mi>ν</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>g</mi></mrow><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mn>1</mn></mrow></msup></math> four-quasiparticle configuration. Thus, MχD based on different configurations is observed in $^{104}$Rh.

Hungary

A. Krakó

D. Sohler

J. Timár

I. Kuti

S.Q. Zhang

J. Meng

Canada

K. Starosta

T. Koike

United Kingdom

E.S. Paul

United States

D.B. Fossan

C. Vaman

Multiple chiral doublet bands in Rh

The critical spin <math><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></math> (or critical frequency <math><mi>ħ</mi><msub><mrow><mi>ω</mi></mrow><mrow><mi>c</mi></mrow></msub></math>) represents the minimum spin (or rotational frequency) required for stable chiral solutions in nuclear systems. The effect of pairing on the critical spin has been examined for the particle-hole configuration <math><mi>π</mi><mo>(</mo><mn>1</mn><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo><mo>⊗</mo><mi>ν</mi><msup><mrow><mo>(</mo><mn>1</mn><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> with a triaxial deformation parameter of <math><mi>γ</mi><mo>=</mo><msup><mrow><mn>30</mn></mrow><mrow><mo>∘</mo></mrow></msup></math> using the particle rotor model, which treats the total angular momentum as a good quantum number. Increasing pairing interaction keeps the critical spin <math><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></math> constant, but decreases the critical rotational frequency <math><mi>ħ</mi><msub><mrow><mi>ω</mi></mrow><mrow><mi>c</mi></mrow></msub></math>. This is due to that the enhanced pairing interaction causes valence nucleons angular momenta to align preferentially along the medium axis, resulting in a larger effective collective moment of inertia and facilitating the emergence of chiral rotation at a lower frequency. However, even with an increase in pairing gap from 0.0 to <math><mn>2.0</mn><mspace width="0.25em"></mspace><mtext>MeV</mtext></math>, the resulting increase in medium axis alignment is less than 1ħ, which is insufficient to change the value of the critical spin <math><msub><mrow><mi>I</mi></mrow><mrow><mi>c</mi></mrow></msub></math>. This study suggests that the critical spin remains robust against the influence of pairing interaction.

Y. Wu

Pairing effect on critical spin in chiral rotation

Abstract The open N = 2 string theory is defined on the 4D space-time with the split signature (+, +, −, −). The string field theory action of the open N = 2 string theory is described by the 4D Wess–Zumino–Witten (WZW$_{4}$) model. The equation of motion of the WZW$_{4}$ model is the Yang equation, which is equivalent to the anti-self-dual Yang–Mills equation. In this paper, we study soliton-type classical solutions of the WZW$_{4}$ model in the split signature by calculating the action density of the WZW$_{4}$ model. We find that the action density of the one-soliton solutions is localized on a 3D hyperplane. This shows that there would be codimension-one-solitonic objects, or equivalently some kind of three-branes in the open N = 2 string theory. We also prove that, in the asymptotic region of the space-time, the action density of the n-soliton solutions is a “non-linear superposition” of n one-solitons. This suggests the existence of n intersecting three-branes in the N = 2 strings. Finally we make a reduction to a (1 + 2)D real space-time to calculate the energy densities of the soliton solutions. We can successfully evaluate the energy distribution for the two-soliton solutions and find that there is no singularity in the interacting region. This implies the existence of smooth intersecting codimension-one branes in the whole region. Soliton solutions in the Euclidean signature are also discussed.

Masashi Hamanaka

Shan-Chi Huang

Hiroaki Kanno

Solitons in open = 2 String Theory Kahler-Chen-Simons theory A tour through N=2 strings On soliton solutions of the anti-self-dual Yang-Mills equations from the perspective of integrable systems Soliton solutions in an integrable chiral model in 2+1 dimensions On the space-time monopole equation A review on tachyon condensation in open string field theories Soliton equations as dynamical systems on infinite dimensional Grassmann manifold

Two nearly degenerate positive-parity bands with the <math><mi>π</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>⊗</mo><mi>ν</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math> configuration and three nearly degenerate negative-parity bands with the <math><mi>π</mi><msub><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>(</mo><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo><mo>⊗</mo><mi>ν</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math> configuration have been identified in $^{81}$Kr. They are interpreted as chiral doublet bands and pseudospin-chiral triplet bands, which is supported by the constrained covariant density functional theory and the multiparticle plus rotor model calculations. The present work reports two new chiral configurations <math><mi>π</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>⊗</mo><mi>ν</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math> and <math><mi>π</mi><msub><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>(</mo><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo><mo>⊗</mo><mi>ν</mi><msubsup><mrow><mi>g</mi></mrow><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math>, and the first example of pseudospin-chiral triplet bands involving the <math><mi>π</mi><mo>(</mo><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></math> pseudospin doublet.

L. Mu

S.Y. Wang

C. Liu

B. Qi

South Africa

R.A. Bark

P. Jones

S.M. Wyngaardt

H. Jia

Z.Q. Li

S. Wang

D.P. Sun

R.J. Guo

X.C. Han

W.Z. Xu

X. Xiao

P.Y. Zhu

H.W. Li

H. Hua

X.Q. Li

C.G. Li

R. Han

B.H. Sun

L.H. Zhu

T.D. Bucher

B.V. Kheswa

N. Khumalo

E.A. Lawrie

J.J. Lawrie

K.L. Malatji

L. Msebi

J. Ndayishimye

J.F. Sharpey-Schafer

O. Shirinda

M. Wiedeking

T. Dinoko

S.S. Ntshangase

First observation of the coexistence of multiple chiral doublet bands and pseudospin doublet bands in the ≈ 80 Mass Region

N. Sensharma

U. Garg

S. Zhu

A.D. Ayangeakaa

S. Frauendorf

W. Li

G.H. Bhat

J.A. Sheikh

M.P. Carpenter

Germany

J.L. Cozzi

Y.K. Gupta

D.J. Hartley

K.B. Howard

R.V.F. Janssens

F.G. Kondev

T.C. McMaken

R. Palit

J. Sethi

D. Seweryniak

R.P. Singh

Corrigendum to “Two-phonon wobbling in Pr” [Phys. Lett. B 792 (2019) 170–174]

The three-dimensional tilted axis cranking covariant density functional theory (3D-TAC CDFT) is used to study the chiral modes in $^{135}$Nd. By modeling the motion of the nucleus in rotating mean field as the interplay between the single-particle motions of several valence particle(s) and hole(s) and the collective motion of a core-like part, a classical Routhian is extracted. This classical Routhian gives qualitative agreement with the 3D-TAC CDFT result for the critical frequency corresponding to the transition from planar to aplanar rotation. Based on this investigation a possible understanding of tilted rotation appearing in a microscopic theory is provided.

J. Peng

Covariant density functional theory for nuclear chirality in Nd

The yrast lines in Kr isotopes with <math><mi>N</mi><mo>=</mo><mn>42</mn></math>, 44, and 46 are investigated in a beyond mean field framework with both prolate-oblate coexistence and quasiparticle alignment taken into account. Quasiparticle orbitals with high-j and low-Ω on the oblate side are shown to be responsible for the sharp backbending observed in $^{82}$Kr, by driving the yrast shape from prolate to oblate. This suggests that quasiparticle alignment may not be neglected in the investigation of the shape evolution along the yrast line.

Fang-Qi Chen

Prolate-to-oblate transition and backbending along the yrast line induced by quasiparticle alignment

The chirality suggested for the doublet bands B2 and B2a in $^{195}$Tl in <math><mi>A</mi><mo>∼</mo><mn>190</mn></math> region is reexamined. The potential-energy curves and the configurations together with the deformation parameters are obtained by the constrained covariant density functional theory. The corresponding experimental energy spectra, energy differences between doublet bands, and the available <math><mi>B</mi><mo>(</mo><mi>M</mi><mn>1</mn><mo>)</mo><mo>/</mo><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>)</mo></math> values are investigated by the fully quantal particle rotor model. Analysis on the basis of the angular momentum components, the K-plots, and the azimuthal plots suggest a planar rotation interpretation for the bands B2 and B2a. Hence, it coexists with the aplanar rotation in the other doublet bands B4 and B4a in $^{195}$Tl.

Coexistence of planar and aplanar rotations in Tl