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Exploring hidden-charm and hidden-strange hexaquark states from lattice QCD

science China(physics,Mechanics & Astronomy) 2024年第1期67卷 30-37页

作者： Hang Liu Jinchen He Liuming Liu Peng Sun Wei Wang Yi-Bo Yang Qi-An Zhang INPAC Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Key Laboratory for Particle Physics and CosmologySchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Maryland Center for Fundamental Physics Department of PhysicsUniversity of MarylandCollege ParkMaryland 20742USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Southern Center for Nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing 100049/Hangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Physics Beihang UniversityBeijing 102206China

Based on five different ensembles of newly generated(2+1)-flavor configurations with pion mass of approximately mπ■(140-310)MeV,we present a lattice analysis of hidden-charm and hidden-strange hexaquarks with the quark content■.The correlation matrices of two types of operators with JPC=0++,0-+,1++and 1--are simulated to extract the masses of the hexaquark candidates,which are subsequently extrapolated to the physical pion mass and continuum *** results indicate that ground state masses are below the■threshold and provide a characteristic signal for the experimental discovery of hexaquark candidates,which may enrich the versatile structure of multiquarks;moreover,it is an indispensable step to decipher the nonperturbative nature of the fundamental interactions of quarks and gluons.

关键词： quantum chromodynamics lattice QCD multiquark states

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Valence mirror symmetry between Z=50 isotopes and N=82 isotones

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Physical Review C 2024年第6期109卷 064306-064306页

作者： Y. Y. Zong C. Ma H. Jiang Y. M. Zhao Shanghai Key Laboratory of Particle Physics and Cosmology School of Physics and Astronomy School of Science Collaborative Innovation Center of IFSA (CICIFSA)

In this paper we study the valence mirror symmetry between the Sn (Z=50) isotopes and N=82 isotones, in the frameworks of the nuclear shell model (NSM) and its nucleon-pair approximation (NPA). The NPA energy spectra and electromagnetic properties for yrast states are well consistent with the shell-model results as well as available data in experiments. Remarkable correspondences of the energy spectra and electromagnetic matrix elements between the even-even Sn isotopes and N=82 isotones are emphasized in both the experimental data and theoretical calculations. The asymmetry of E21+ values are explained in terms of the evolution of single-particle energy splitting between the 1g7/2 and 2d5/2 orbits for the N=82 isotones.

关键词： Energy levels Nuclear structure & decays Shell model 90 ≤ A ≤ 149 Magnetic moment

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NMSSM neutralino dark matter for CDFⅡW-boson mass and muon g-2 and the promising prospect of direct detection

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science China(physics,Mechanics & Astronomy) 2023年第3期66卷 169-177页

作者： Tian-Peng Tang Murat Abdughani Lei Feng Yue-Lin Sming Tsai Jian Wu Yi-Zhong Fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210033China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China Joint Center for Particle Nuclear Physics and CosmologyNanjing University-Purple Mountain ObservatoryNanjing 210093China

Two experiments from the Fermilab, E989 and CDF II, have reported two anomalies for muon g-2 and W-boson mass that may indicate the new physics at the low energy scale. Here we examine the possibility of a common origin of these two anomalies in the Next-to-Minimal Supersymmetric Standard Model. Considering various experimental and astrophysical constraints such as the Higgs mass, collider data, flavor physics, dark matter relic density, and direct detection experiments, we find that lighter electroweakinos and sleptons can generate sufficient contributions to muon g-2 and mW. Moreover, the corresponding bino-like neutralino dark matter mass is in the ~ 180-280 Ge V range. Interestingly, the favored dark matter(DM) mass region can soon be entirely probed by ongoing direct detection experiments like Panda X-4T, XENONn T, LUX-ZEPLIN, and DARWIN.

关键词： supersymmetry dark matter W-boson muon g-2

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Identification of isoscalar spin-aligned pair condensation versus conventional isovector pairing correlation in Cd96 with Gamow-Teller transitions

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Physical Review C 2025年第5期111卷 L051303-L051303页

作者： C. Ma X. Yin Y. M. Zhao School of Science Yanshan University Qinhuangdao 066004 China Shanghai Key Laboratory of Particle Physics and Cosmology School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Collaborative Innovation Center of IFSA (CICIFSA) Shanghai Jiao Tong University Shanghai 200240 China

The geometric similarity of wave functions assuming isoscalar spin-aligned and isovector pairing correlations challenges our understanding of the isospin nature for nucleon pairs in low-lying nuclear states. Instead of energy levels and electromagnetic properties, integrated Gamow-Teller decay rates are found to be sensitive and parameter-free quantities to discriminate between the two scenarios in Cd96. Analytical formulas of the decay rates for T=0 yrast states of Cd96 are derived from a single-j (g9/2) shell, the validity of which model space is supported by examining details of Gamow-Teller transition rates with shell-model calculations using three sets of effective interactions in the f5pg9 shell. The experimental logft value of the 01+ ground state does not conform with spin-aligned pair condensation and is more appropriate to interpret in terms of the conventional isovector pairing correlation; on the other hand, for the isomeric 161+ state, the experimental datum is well consistent with the isoscalar spin-aligned pair condensation.

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Covariant quantum field theory of tachyons is unphysical

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Physical Review D 2024年第11期110卷 115042-115042页

作者： Krzysztof Jodłowski Particle Theory and Cosmology Group Center for Theoretical Physics of the Universe Institute for Basic Science (IBS) Daejeon 34126 Korea

Tachyons have fascinated generations of physicists due to their peculiar behavior, but they did not solve any real physical problem. This may have changed with the recent works of Dragan et al. [J. Paczos et al., Covariant quantum field theory of tachyons, Phys. Rev. D 110, 015006 (2024); A. Dragan and A. Ekert, Quantum principle of relativity, New J. Phys. 22, 033038 (2020); A. Dragan and A. EkertNew J. Phys.25, 088002(A) (2023); A. Dragan, K. Dębski, S. Charzyński, K. Turzyński, and A. Ekert, Relativity of superluminal observers in 1+3 spacetime, Classical Quantum Gravity 40, 025013 (2023); J. Paczos, S. Cedrowski, K. Turzyński, and A. Dragan, Higgs field as a source of tachyons, arXiv:2407.06640], who have shown that superluminal observers may be related to the foundations of quantum mechanics (QM) because they require introducing nondeterminism and wavelike behavior at the fundamental level. Unfortunately, we show that the tachyon quantum field theory proposed as a part of this program is not quantum since the tachyon field commutes at all points and the canonical commutations relations of a quantum scalar field are not satisfied. We also discuss other authors’ theories, e.g., we show that the Dhar-Sudarshan’s formula for the Feynman propagator violates unitarity, and we apply the Lehmann–Symanzik–Zimmermann (LSZ) formalism to tachyons for the first time, where we find that one cannot prove the LSZ asymptotic condition just by replacing plane waves with wave packets.

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Black holes in Einstein-scalar-Gauss-Bonnet model probed with scattering amplitudes

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Physical Review D 2024年第4期110卷 046025页

作者： Boris Latosh Miok Park Particle Theory and Cosmology Group Center for Theoretical Physics of the Universe Institute for Basic Science (IBS) Daejeon 34126 South Korea

We examined the quantum properties of scalar-tensor gravity with a coupling to the Gauss-Bonnet term in the low-energy limit, exploring both linear and quadratic couplings. We calculated the leading-order corrections to the nonrelativistic one-body gravitational potential and the metric by studying the gravitational field of a pointlike scalar particle. We studied lightlike scattering and compared it with the classical theory. We found that the nonminimal coupling does not contribute to the small-angle scattering for the quadratic coupling but does in the case of linear coupling. The results provide an opportunity to constrain the linear nonminimal coupling to the Gauss-Bonnet term with forthcoming observational data.

关键词： Alternative gravity theories Effective field theory Feynman diagrams General relativity Perturbation theory Quantum gravity Scattering amplitudes

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Position: Is machine learning good or bad for the natural sciences? 41

Position: Is machine learning good or bad for the natural sc...

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41st International Conference on Machine Learning, ICML 2024

作者： Hogg, David W. Villar, Soledad Center for Cosmology and Particle Physics Department of Physics New York University United States Max-Planck-Institut für Astronomie Heidelberg Germany Flatiron Institute New York United States Department of Applied Mathematics and Statistics Johns Hopkins University United States Mathematical Institute for Data Science Johns Hopkins University United States

Machine learning (ML) methods are having a huge impact across all of the sciences. However, ML has a strong ontology-in which only the data exist-and a strong epistemology-in which a model is considered good if it performs well on held-out training data. These philosophies are in strong conflict with both standard practices and key philosophies in the natural sciences. Here we identify some locations for ML in the natural sciences at which the ontology and epistemology are valuable. For example, when an expressive machine learning model is used in a causal inference to represent the effects of confounders, such as foregrounds, backgrounds, or instrument calibration parameters, the model capacity and loose philosophy of ML can make the results more trustworthy. We also show that there are contexts in which the introduction of ML introduces strong, unwanted statistical biases. For one, when ML models are used to emulate physical (or first-principles) simulations, they amplify confirmation biases. For another, when expressive regressions are used to label datasets, those labels cannot be used in downstream joint or ensemble analyses without taking on uncontrolled biases. The question in the title is being asked of all of the natural sciences;that is, we are calling on the scientific communities to take a step back and consider the role and value of ML in their fields;the (partial) answers we give here come from the particular perspective of physics. Copyright 2024 by the author(s)

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Cosmological perturbations in the energy-momentum squared gravity theory:constraints from gravitational wave standard sirens and redshift space distortions

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Chinese physics C 2025年第4期49卷 199-208页

作者： Qi-Ming Fu Xin Zhang Institute of Physics Shaanxi University of TechnologyHanzhong 723000China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China Key Laboratory of Cosmology and Astrophysics(Liaoning)&College of Sciences Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China

We investigate the linear cosmological perturbations in the context of the so-called energy-momentum squared gravity(EMSG)*** research shows that the EMSG theory can reproduce a viable background cosmological evolution comparable toΛCDM,whereas the matter-dominated era exhibits slight *** this paper,we focus on power-law EMSG models and derive the equations for the linear cosmological *** explore the propagation of the gravitational wave(GW)and the growth of matter density perturbation at the first order,and we estimate the model parameters from the simulated GW and observed redshift space distortion *** analysis reveals that the model parameters should be small and positive in the confidence interval,which indicates that the theory agrees closely with the observational data and can be considered an alternative to the standard cosmological model.

关键词： energy-momentum squared gravity cosmological perturbations gravitational wave cosmological parameters

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Layout optimization and performance analysis of large array of imaging atmospheric Cherenkov telescopes

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Chinese physics C 2025年第3期49卷 161-170页

作者： Zhipeng Zhang Ruizhi Yang Shoushan Zhang Zhen Xie Jiali Liu Liqiao Yin Yudong Wang Lingling Ma Zhen Cao School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China Deep Space Exploration Laboratory/School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsBeijing 100049China Department of Physics University of Chinese Academy of SciencesBeijing 100049China Tianfu Cosmic Ray Research Center Chengdu 610299China

The large array of imaging atmospheric Cherenkov telescopes(LACT)is a planned array of 32 Cherenkov telescopes,each featuring 6-m diameter mirrors,to be constructed at the LHAASO *** study focused on optimizing the array layout and analyzing the performance of *** observation modes were examined:large zenith angle observations for ultra-high energy events and small zenith angle observations for lower energy *** large zenith angles(60°),simulations indicate that an 8-telescope subarray can achieve an effective area of 3km^(2)with excellent angular *** small zenith angles,we optimized the layout of 4-telescope cells and the full 32-telescope *** energy threshold of the full array is approximately 200 GeV,which is particularly crucial for studying transient phenomena such as gamma-ray bursts(GRBs)and active galactic nuclei(AGNs).This study provides essential guidance for finalizing the LACT layout design and estimating performance under various observational *** also highlights the potential of LACT for conducting deep observations of ultra-high energyγ-ray sources,performing morphological studies of PeVatrons,and advancing time-domainγ-ray astronomy.

关键词： IACT γ-ray LHAASO

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Non-Gaussianity from two-field warm inflation

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Physical Review D 2024年第8期110卷 083522页

作者： Yi-Yang Shi Chun-Shuo Jia Xi-Bin Li Xiao-Min Zhang Narsu Bai College of Physics and Electronic Information Research center of particle physics and cosmology Department of Physics School of Science Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials

Two-field models are introduced in the warm inflation to analyze the primordial non-Gaussianity of gauge-invariant perturbation. With the assumptions of slow-roll approximation, strong dissipation and temperature independence of dissipative coefficients, bispectrum and nonlinearity functions are analytically obtained via the Green’s function method. In our analysis, thermal effects of nonadiabaticity and entropy fluctuations in warm inflation contribute mainly to the non-Gaussianity. The former is characterized by the slow-roll parameter β, a unique parameter of warm inflation, and the latter is associated with the perturbations of cosmic temperature, interpreted as thermal fluctuations from the thermalized radiation bath. Therefore, compared to the cold inflation model, the non-Gaussianity form of the warm inflation has significantly different physical meanings. Two models with constant and field-dependent dissipative coefficients are introduced, and both confirm that a stronger damping will enhance the non-Gaussianity. From the numerical results, it is still possible to predict an observably large tensor-to-scalar ratio, with amplitude of r∼10−3–10−4.

关键词： Cosmological parameters Inflation Large scale structure of the Universe

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