We propose a search strategy at the HL-LHC for a new neutral particle $\textit{X}$ that couples to $\textit{W}$-bosons, using the process $ p p \to W^{\pm} X (\to W^{+} W^{-}) $ with a tri-$\textit{W}$-boson final state. Focusing on events with two same-sign leptonic $\textit{W}$-boson decays into muons and a hadronically decaying $\textit{W}$-boson, our method leverages the enhanced signal-to-background discrimination achieved through a machine-learning-based multivariate analysis. Using the heavy photophobic axion-like particle (ALP) as a benchmark, we evaluate the discovery sensitivities on both production cross section times branching ratio $ \sigma(p p \to W^{\pm} X) \times \text{Br}(X \to W^{+} W^{-}) $ and the coupling $ g_{aWW} $ for particle mass over a wide range of 170–3000 GeV at the HL-LHC with center-of-mass energy $ \sqrt{s} = 14 \, \text{ TeV} $ and integrated luminosity $ {\cal{L}} = 3 \, \text{ab}^{-1} $ . Our results show significant improvements in discovery sensitivity, particularly for masses above 300 GeV, compared to existing limits derived from CMS analyses of Standard Model (SM) tri-$\textit{W}$-boson production at $ \sqrt{s} = 13 \, \text{ TeV} $ . This study demonstrates the potential of advanced selection techniques in probing the coupling of new particles to $\textit{W}$-bosons and highlights the HL-LHC's capability to explore physics beyond the SM.

China

Ying-nan Mao

Kechen Wang

Yiheng Xiong

Sensitivities of new resonance couplings to $\textit{W}$-bosons at the LHC * Ying-nan Mao and Yihen Xiong are supported by the National Natural Science Foundation of China (12205227). Kechen Wang is supported by the National Natural Science Foundation of China (11905162), the Excellent Young Talents Program of the Wuhan University of Technology (40122102), and the research program of the Wuhan University of Technology (2020IB024). The simulation and analysis work of this article was completed with the computational cluster provided by the Theoretical Physics Group at the Department of Physics, School of Physics and Mechanics, Wuhan University of Technology

We study $ \cos2\phi $ azimuthal asymmetry in doubly longitudinally polarized proton-proton Drell-Yan collisions within the transverse momentum dependent factorization framework. The asymmetry arises from the convolution of the longitudinal transversity distribution $ h_{1L}^{\perp} $ for both protons. Using the Bacchetta-Delcarro-Pisano-Radici-Signori parameterization for the nonperturbative Sudakov form factor and the Wandzura-Wilczek approximation for collinear $ h_{1L}^{\perp} $ , we predict the double spin asymmetry $ A_{LL}^{\cos2\phi} $ at RHIC and NICA kinematics. Our results demonstrate sensitivity to sea quark distributions, with the asymmetry reaching up to 25% for maximal sea quark contributions. These predictions highlight the potential of polarized Drell-Yan measurements to probe sea quark dynamics and advance our understanding of nucleon structures.

Hui Li

Ting Hu

Liang-Liang Liu

Xiao-Yu Wang

Zhun Lu

Asymmetry ${{\boldsymbol A}_{\boldsymbol{LL}}^{\bf\cos2\boldsymbol\phi}} $ in the polarized proton-proton Drell-Yan process within TMD factorization * Hui Li is supported by Fundamental Research Program of Shanxi Province (202203021222224) and Natural Science Foundation of Shanxi Normal University (JCYJ2023021). Xiao-Yu Wang is supported by the Natural Science Foundation of Henan Province (242300421377, 232300421140)

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.

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)

A new proton-unbound isotope 204Ac was produced in the fusion-evaporation reaction <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Tm</mi><mo stretchy='false'>(</mo><msup><mrow /><mrow><mn mathvariant='normal'>40</mn></mrow></msup></mrow><mprescripts /><none /><mrow><mn>169</mn></mrow></mmultiscripts><mrow><mi mathvariant='normal'>Ca</mi></mrow><mo>,</mo><msup><mrow><mn mathvariant='normal'>5n</mn><mo stretchy='false'>)</mo></mrow><mrow><mn mathvariant='normal'>204</mn></mrow></msup><mrow><mi mathvariant='normal'>Ac</mi></mrow></math> and identified via the recoil- <italic>&#945;</italic> correlation at the gas-filled recoiled separators SHANS2 and SHANS. The excitation function for producing 204Ac was measured and the optimal beam energy was evaluated to be 212 MeV. Nineteen ER - <math altimg='si2.svg'><msub><mrow><mi>&#945;</mi></mrow><mrow><mn mathvariant='normal'>1</mn></mrow></msub></math> - <math altimg='si3.svg'><msub><mrow><mi>&#945;</mi></mrow><mrow><mn mathvariant='normal'>2</mn></mrow></msub></math> - <math altimg='si4.svg'><msub><mrow><mi>&#945;</mi></mrow><mrow><mn mathvariant='normal'>3</mn></mrow></msub></math> decay chains were observed for this isotope. Based on these chains, the <italic>&#945;</italic>-particle energy and half-life of 204Ac were determined to be 7948(15) keV and 7.4 <math altimg='si5.svg'><msubsup><mrow /><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>1.4</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>2.2</mn></mrow></msubsup></math> ms, respectively. Both are consistent with the theoretical prediction. The reduced <italic>&#945;</italic>-decay width was deduced to be 49 <math altimg='si6.svg'><msubsup><mrow /><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>15</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>10</mn></mrow></msubsup></math> keV, which indicates a favored <italic>&#945;</italic> decay for 204Ac. In addition, more precise decay properties of <math altimg='si32.svg'><msub><mrow><mi>E</mi></mrow><mrow><mi>&#945;</mi></mrow></msub></math> = 7883(15) keV and <math altimg='si8.svg'><msub><mrow><mi>T</mi></mrow><mrow><mn mathvariant='normal'>1</mn><mo stretchy='false'>/</mo><mn mathvariant='normal'>2</mn></mrow></msub></math> = 7.7 <math altimg='si9.svg'><msubsup><mrow /><mrow><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>1.6</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>2.7</mn></mrow></msubsup></math> ms were obtained for 205Ac.

M.H. Huang

Z.G. Gan

Z.Y. Zhang

L. Ma

J.G. Wang

M.M. Zhang

H.B. Yang

C.L. Yang

X.Y. Huang

Z. Zhao

S.Y. Xu

L.X. Chen

X.J. Wen

Y.F. Niu

C.X. Yuan

Y.L. Tian

Y.S. Wang

J.Y. Wang

M.L. Liu

Y.H. Qiang

W.Q. Yang

H.B. Zhang

Z.W. Lu

S. Guo

W.X. Huang

Y. He

Z.Z. Ren

S.G. Zhou

X.H. Zhou

H.S. Xu

Russia

V.K. Utyonkov

A.A. Voinov

Yu.S. Tsyganov

A.N. Polyakov

<italic>&#945;</italic> decay of the new isotope 204Ac

A new isotope $^{203}$Ac was produced in the reaction $^{40}$Ca + $^{169}$Tm at beam energy of 226 MeV. One correlated α-decay chain was attributed to $^{203}$Ac. The α-particle energy and half-life were determined to be 8217(16) keV and <math><msubsup><mrow><mn>56</mn></mrow><mrow><mo>−</mo><mn>26</mn></mrow><mrow><mo>+</mo><mn>269</mn></mrow></msubsup></math> μs, respectively. The reduced α-decay width (<math><msup><mrow><mi>δ</mi></mrow><mrow><mn>2</mn></mrow></msup></math>) of $^{203}$Ac was deduced to be <math><msubsup><mrow><mn>1096</mn></mrow><mrow><mo>−</mo><mn>906</mn></mrow><mrow><mo>+</mo><mn>921</mn></mrow></msubsup></math> keV, which indicates a favored α decay. The systematics of <math><msup><mrow><mi>δ</mi></mrow><mrow><mn>2</mn></mrow></msup></math> and single-particle energy levels indicate that the new state probably arises from the intruder <math><msub><mrow><mi>s</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math> configuration, which shows an onset of deformation in Ac isotopes. The proton separation energy <math><msub><mrow><mi>S</mi></mrow><mrow><mi>p</mi></mrow></msub></math> of $^{203}$Ac was extracted as <math><mo>−</mo><mn>1214</mn><mo>(</mo><mn>22</mn><mo>)</mo></math> keV and the systematics of <math><msub><mrow><mi>S</mi></mrow><mrow><mi>p</mi></mrow></msub></math> for odd-A isotopes beyond proton drip line were discussed.

Z.C. Li

L.C. Sun

H. Zhou

X. Zhang

X.L. Wu

JINR

-decay Properties of new Neutron-deficient Isotope Ac

The precession of an atomic nucleus can be approximately described as wobbling motion, arising from the coupling of a rotation and a harmonic vibration. Recently, a number of wobbling bands were reported at low spin, which violate the wobbling approximation that can be valid only at high spin. In the present work, we explore the nature of the reported low-spin wobbling bands. Via a new experiment including both angular correlation and linear polarization measurements, we demonstrate that one such band in $^{187}$Au is generated by dominant single-particle excitation rather than by the excitation of a wobbling phonon. Assessing the experimental proofs and discussions to assign the reported low-spin wobbling bands, we further point out that the imperfect research paradigm used previously would lead to unreliable identification of low-spin wobbling bands.

France

C.M. Petrache

South Africa

E.A. Lawrie

S.H. Mthembu

Y.D. Fang

H.Y. Wu

H.L. Wang

H.Y. Meng

G.S. Li

Y. Zheng

B. Ding

W.Q. Zhang

A. Rohilla

K.R. Muhki

Y.Y. Yang

H.J. Ong

J.B. Ma

S.W. Xu

Z. Bai

H.L. Fan

J.F. Huang

J.H. Li

J.H. Xu

B.F. Lv

W. Hua

Y.H. Zhang

Probing the nature of the conjectured low-spin wobbling bands in atomic nuclei

The electromagnetic character of the <math><mi>Δ</mi><mi>I</mi><mo>=</mo><mn>1</mn></math> transitions connecting the 1- to 0-phonon and the 2- to 1-phonon wobbling bands should be dominated by an E2 component, due to the collective motion of the entire nuclear charge. In the present work it is shown, based on combined angular correlation and linear polarization measurements, that the mixing ratios of all analyzed connecting transitions between low-lying bands in $^{135}$Pr interpreted as 0-, 1-, and 2-phonon wobbling bands, have absolute values smaller than one. This indicates predominant M1 magnetic character, which is incompatible with the proposed wobbling nature. All experimental observables are instead in good agreement with quasiparticle-plus-triaxial-rotor model calculations, which describe the bands as resulting from a rapid re-alignment of the total angular momentum from the short to the intermediate nuclear axis.

A. Astier

K.K. Zheng

Z.Y. Sun

Finland

P.T. Greenlees

H. Badran

United Kingdom

T. Calverley

Sweden

D.M. Cox

T. Grahn

J. Hilton

R. Julin

S. Juutinen

CERN

J. Konki

J. Pakarinen

P. Papadakis

J. Partanen

P. Rahkila

P. Ruotsalainen

M. Sandzelius

J. Sarén

C. Scholey

J. Sorri

United States

S. Stolze

J. Uusitalo

B. Cederwall

A. Ertoprak

H. Liu

Hungary

I. Kuti

J. Timár

Poland

A. Tucholski

J. Srebrny

Canada

C. Andreoiu

Evidence against the wobbling nature of low-spin bands in Pr

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.

Germany

Michał Czakon

Andrea Ferroglia

Alexander Mitov

Davide Pagani

Andrew S. Papanastasiou

Benjamin D. Pecjak

Netherlands

Darren J. Scott

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
						

Three nearly degenerate pairs of doublet bands are identified in $^{131}$Ba. Two of them, with positive-parity, are interpreted as pseudospin-chiral quartet bands. This is the first time that a complete set of chiral doublet bands built on the pseudospin partners <math><mi>π</mi><mo>(</mo><msub><mrow><mi>d</mi></mrow><mrow><mn>5</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msub><mo>)</mo></math> is observed. The chiral bands with opposite parity built on 3-quasiparticle configurations are directly connected by many E1 transitions, without involving an intermediary non-chiral configuration. The observed band structures in $^{131}$Ba have been investigated by using the reflection-asymmetric particle rotor model. The energies and the electromagnetic transition ratios of the three pairs of doublet bands observed in $^{131}$Ba are reproduced and they are interpreted as chiral doublet bands with three-quasiparticle configurations. It is the first time that multiple chiral bands are observed in the presence of enhanced octupole correlations and pseudospin symmetry.

D. Mengoni

Y.P. Wang

Y.Y. Wang

Japan

J. Meng

Y.K. Wang

S.Q. Zhang

P.W. Zhao

E. Dupont

D. Bazzacco

A. Boso

A. Goasduff

F. Recchia

D. Testov

F. Galtarossa

G. Jaworski

D.R. Napoli

S. Riccetto

M. Siciliano

J.J. Valiente-Dobon

F.H. Garcia

K. Ortner

K. Whitmore

A. Ataç-Nyberg

T. Bäck

D. Sohler

T. Marchlewski

Evidence for pseudospin-chiral quartet bands in the presence of octupole correlations

The mass of $^{27}$P is expected to impact the X-ray burst (XRB) model predictions of burst light curves and the composition of the burst ashes, but large uncertainties and inconsistencies still exist in the reported $^{27}$P masses. We have used the β-decay spectroscopy of $^{27}$S to determine the most precise mass excess of $^{27}$P to date to be <math><mo>−</mo><mn>659</mn><mo>(</mo><mn>9</mn><mo>)</mo></math> keV, which is 63 keV (2.3σ) higher and a factor of 3 more precise than the value recommended in the 2016 Atomic Mass Evaluation. Based on the new $^{27}$P mass, the <math><mmultiscripts><mrow><mi>Si</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>26</mn></mrow></mmultiscripts><msup><mrow><mo>(</mo><mi>p</mi><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>27</mn></mrow></msup></math>P reaction rate and its uncertainty were recalculated using Monte Carlo techniques. We also estimated the previously unknown mass excess of $^{27}$S to be 17678(77) keV, based on the measured β-delayed two-proton energy and the Coulomb displacement energy relations. The impact of these well-constrained masses and reaction rates on the modeling of the explosive astrophysical scenarios has been investigated by post-processing XRB and hydrodynamic nova models. Compared to the model calculations based on the masses and rates from databases, the abundance of <math><mi>A</mi><mo>=</mo><mn>26</mn></math> in the burst ashes is increased by a factor of 2.4, while no substantial change was found in the XRB energy generation rate or the light curve. Our calculation also suggests that $^{27}$S is not a significant waiting point in the rapid proton capture process, and the change of the <math><mmultiscripts><mrow><mi>Si</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>26</mn></mrow></mmultiscripts><msup><mrow><mo>(</mo><mi>p</mi><mo>,</mo><mi>γ</mi><mo>)</mo></mrow><mrow><mn>27</mn></mrow></msup></math>P reaction rate is not sufficiently large to affect the conclusion previously drawn on the nova contribution to the synthesis of galactic $^{26}$Al.

Hong Kong

L.J. Sun

X.X. Xu

S.Q. Hou

C.J. Lin

Spain

J. José

J. Lee

J.J. He

Z.H. Li

J.S. Wang

F. Herwig

J. Keegans

T. Budner

D.X. Wang

P.F. Liang

Y.H. Lam

P. Ma

F.F. Duan

Z.H. Gao

Experimentally well-constrained masses of P and S: Implications for studies of explosive binary systems