The production of heavy-quark (HQ) jets is a new area that addresses the mass effect of jet quenching in heavy-ion physics. This paper presents a theoretical study of HQ jet yield suppression in Pb+Pb collisions at the Large Hadron Collider (LHC) and focuses on the energy loss of HQ jets produced by different mechanisms. The $\textit{p+p}$ baseline is provided by the generator simulation of high-energy reactions of particles (SHERPA), and the jet-medium interactions are described by the SHELL transport model, which considers the elastic and inelastic partonic energy loss in the quark-gluon plasma (QGP). In $\textit{p+p}$ collisions, our numerical results indicate that the HQ jets from gluon splitting ( $ g \rightarrow Q $ -jet) are the dominant contribution at high $ p_T $ , displaying more dispersive structures than the HQ-initiated ( $ Q \rightarrow Q $ -jet). In nucleus-nucleus collisions, our calculations were consistent with the inclusive and b-jet $ R_{AA} $ recently measured by the ATLAS collaboration, revealing a remarkable manifestation of the mass effect of jet energy loss. As a result of the dispersive substructure, the $ g \rightarrow Q $ -jet loses more energy than the $ Q \rightarrow Q $ -jet in the QGP. Due to the significant contribution of $ g \rightarrow c $ -jet, the $ R_{AA} $ of $\textit{c}$-jet is comparable or even smaller than that of inclusive jet. To experimentally distinguish the $ g \rightarrow Q $ -jet and $ Q \rightarrow Q $ -jet, we propose event selection strategies based on their topological features and test their performances. By isolating the $ c \rightarrow c $ -jet, $ b \rightarrow b $ -jet, and the jets initiated by heavy quarks, we predicted that the order of their $ R_{AA} $ are in line with the mass hierarchy of energy loss. Future measurements on the $ R_{AA} $ of $ Q \rightarrow Q $ -jet and $ g \rightarrow Q $ -jet will provide a unique opportunity for testing the flavor/mass dependence of energy loss at the jet level.

China

Sa Wang

Shuang Li

Yao Li

Ben-Wei Zhang

Enke Wang

Probing the mass effect of heavy quark jets in high-energy nuclear collisions * Supported by the MajorProject of Basic and Applied Basic Research of Guangdong Province, China (2020B0301030008, 2023A1515011460), and the National Natural Science Foundation of China (11935007, 12035007, 12247127, 12375137). Sa Wang is supported by the Open Foundation of Key Laboratory of Quark and Lepton Physics (MOE) (QLPL2023P01) and the Talent Scientific Star-up Foundation of the China Three Gorges University, China (CTGU) (2024RCKJ013)

High-spin states in neutron-rich indium isotope $^{116}$In have been observed for the first time by using incomplete fusion of $^{7}$Li on a $^{116}$Cd target at a beam energy of 42 MeV. A negative-parity band with <math><mi>π</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><mo>⊗</mo><mi>ν</mi><msub><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub></math> configuration and a pair of positive-parity doublet bands with <math><mi>π</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><mo>⊗</mo><mi>ν</mi><mo>(</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>/</mo><msub><mrow><mi>d</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo><msubsup><mrow><mi>h</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup></math> configurations have been identified. The positive-parity doublet bands are tentatively interpreted as chiral doublet bands, which is supported by the adiabatic and configuration-fixed constrained triaxial relativistic-mean-field and multiparticle plus rotor model calculations. This observation reports a possible new region of chirality in neutron-rich A≈ 120 mass region.

W.Z. Xu

S.Y. Wang

X.G. Wu

H. Jia

C. Liu

H.F. Bai

Y.J. Li

B. Qi

H.Y. Zhang

G.S. Li

Y. Zheng

C.B. Li

L. Mu

A. Rohilla

S. Wang

D.P. Sun

Z.Q. Li

N.B. Zhang

R.J. Guo

X.C. Han

X. Xiao

First observation of high-spin states in In and possible new region of chirality

Level lifetimes for the candidate chiral doublet bands of $^{80}$Br were extracted by means of the Doppler-shift attenuation method. The absolute transition probabilities derived from the lifetimes agree well with the M1 and E2 chiral electromagnetic selection rules, and are well reproduced by the triaxial particle rotor model calculations. Such good agreements among the experimental data, selection rules of chiral doublet bands and theoretical calculations are rare and outstanding in researches of nuclear chirality. Besides odd-odd Cs isotopes, odd-odd Br isotopes in the A≈ 80 mass region represent another territory that exhibits the ideal selection rules expected for chiral doublet bands.

Germany

R. Schwengner

F. Dönau

T. Servene

H. Schnare

J. Reif

G. Winter

L. Käubler

H. Prade

S. Skoda

J. Eberth

H.G. Thomas

F. Becker

B. Fiedler

S. Freund

Austria

S. Kasemann

T. Steinhardt

O. Thelen

T. Härtlein

C. Ender

F. Köck

P. Reiter

D. Schwalm

Lifetime measurements in Br and a new region for observation of chiral electromagnetic selection rules

The analysis of mixing ratios δ of the ΔI =1 linking transitions in the chiral and multiple chiral doublet bands with the ideal case are theoretically performed for the first time by employing the quantum particle rotor model. The calculated E2 fraction extracted from the mixing ratio show that the ΔI =1 linking transitions in the lowest and excited chiral doublet bands are of the pure M1 character, while those connecting the excited to lowest chiral doublet bands are of <math><mi>M</mi><mn>1</mn><mo>/</mo><mi>E</mi><mn>2</mn></math> character with a relatively large E2 admixture. The further analysis of the angular momentum geometry and azimuthal plots reveals that the excited chiral doublet bands represents a chiral geometry with a wobbling motion of the core. This provides a possible figure of wobbling motion in multiple chiral doublets.

L. Zhu

Possible wobbling motion in multiple chiral doublets

Nearly degenerate positive-parity doublet bands and several E1 transitions between positive- and negative-parity bands have been identified in $^{76}$Br. These experimental observations are interpreted as the coexistence of chirality and octupole correlations, based on the analysis of detailed γ-ray spectroscopy with the precise lifetime measurements and theoretical calculations, and play a key role to explore the simultaneous breaking of chiral and reflection symmetry and their interplay. The present work provides the first test for chirality in the <math><mi>A</mi><mo>≈</mo><mn>80</mn></math> mass region by lifetime measurements, and firstly elucidates the formation of chiral geometry in the presence of the octupole correlations in Br isotopes, leading to the conclusion that the reflection symmetry breaking catalyzes rather than destroys chiral symmetry breaking in nuclear systems.

J. Zhao

Y.M. Zhang

C.L. Wang

Y. Li

Interplay between nuclear chiral and reflection symmetry breakings revealed by the lifetime measurements in Br

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.

South Africa

R.A. Bark

Japan

J. Meng

S.Q. Zhang

P. Jones

S.M. Wyngaardt

Q.B. Chen

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

We describe predictions for top quark pair differential distributions at hadron colliders, by combining the next-to-next-to-leading order quantum chromodynamics calculations and next-to-leading order electroweak corrections with double resummation at the next-to-next-to-leading logarithmic accuracy of threshold logarithms and small-mass logarithms. To the best of our knowledge, this is the first study to present such a combination, which incorporates all known perturbative information. Numerical results are presented for the invariant-mass distribution, transverse-momentum distribution, and rapidity distributions.

Michał Czakon

United States

Andrea Ferroglia

United Kingdom

Alexander Mitov

Davide Pagani

Andrew S. Papanastasiou

Benjamin D. Pecjak

Netherlands

Darren J. Scott

Sweden

Ioannis Tsinikos

Xing Wang

Li Lin Yang

Italy

Marco Zaro

Top quark pair production at complete NLO accuracy with NNLO+NNLL′ corrections in QCD L. L. Yang and X. Wang are supported in part by the National Natural Science Foundation of China (11975030, 11635001, 11575004). X. Wang is also supported in part by the Cluster of Excellence PRISMA+ (project ID 39083149). D. J. S. is supported under the ERC grant ERC-STG2015-677323. The work of D. P. and I. T. is supported by the Alexander von Humboldt Foundation, in the framework of the Sofja Kovalevskaja Award Project "Event Simulation for the Large Hadron Collider at High Precision". D. P. is also supported by the Deutsche Forschungsgemeinschaft (DFG) under Germany’s Excellence Strategy – EXC 2121"Quantum Univers" – 390833306. I. T. is also supported by the Swedish Research Council under contract number 2016-05996. The research of A. M. and A. P. has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (683211) as well as from UK STFC grants ST/L002760/1 and ST/K004883/1. The work of M. C. was supported in part by a grant of the BMBF and by the Deutsche Forschungs-gemeinschaft under grant 396021762 - TRR 257
						

The decay of $^{218}$Pa was investigated by means of α and γ spectroscopy. The nucleus was produced in the fusion reaction $^{40}$Ar+$^{182}$W and separated in flight by the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). The known α decays of $^{218}$Pa were measured with improved precision and newly assigned to be originating from the ground state, which clarified the ambiguities in their previous assignments. In addition, a new isomeric state in $^{218}$Pa decaying with α-particle energies of 9691(15) keV, 9595(21) keV and a half-life of <math><msubsup><mrow><mn>135</mn></mrow><mrow><mo>−</mo><mn>32</mn></mrow><mrow><mo>+</mo><mn>62</mn></mrow></msubsup></math> μs was identified. The spins and parities of the involved states were tentatively assigned on the basis of the systematic α-decay properties of the odd-proton <math><mi>N</mi><mo>=</mo><mn>127</mn></math> isotones and shell model calculations.