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2025-1 Contents
2025, 49(1): 1-3.
Abstract:
Prediction of energy resolution in the JUNO experiment
Angel Abusleme, Thomas Adam, Kai Adamowicz, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Marco Beretta, Antonio Bergnoli, Daniel Bick, Lukas Bieger, Svetlana Biktemerova, Thilo Birkenfeld, Iwan Blake, David Blum, Simon Blyth, Anastasia Bolshakova, Mathieu Bongrand, Clément Bordereau, Dominique Breton, Augusto Brigatti, Riccardo Brugnera, Riccardo Bruno, Antonio Budano, Jose Busto, Anatael Cabrera, Barbara Caccianiga, Hao Cai, Xiao Cai, Yanke Cai, Zhiyan Cai, Stéphane Callier, Steven Calvez, Antonio Cammi, Agustin Campeny, Chuanya Cao, Guofu Cao, Jun Cao, Rossella Caruso, Cédric Cerna, Vanessa Cerrone, Jinfan Chang, Yun Chang, Auttakit Chatrabhuti, Chao Chen, Guoming Chen, Pingping Chen, Shaomin Chen, Xin Chen, Yiming Chen, Yixue Chen, Yu Chen, Zelin
2025, 49(1): 013003. doi: 10.1088/1674-1137/ad83aa
Abstract:
This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of the liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The results of this study reveal an energy resolution of 2.95% at 1 MeV. Furthermore, this study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data collection. Moreover, it provides a guideline for comprehending the energy resolution characteristics of liquid scintillator-based detectors.
LETTERS
Robustness of N=152 and Z=108 shell closures in superheavy mass region
Buyu Chen, Jianmin Dong, Yaqian Wang, Guoqing Wu
2025, 49(1): 011001. doi: 10.1088/1674-1137/ad8d4b
Abstract:
The neutron shell gap at \begin{document}$ N=152 $\end{document} has been experimentally confirmed through high-precision mass measurements on nobelium (\begin{document}$ Z=102 $\end{document}) and lawrencium (\begin{document}$ Z=103 $\end{document}) isotopes. The experimental measurements on α-decay properties suggest that deformed doubly-magic nature of \begin{document}$ ^{270} $\end{document}Hs. However, the magic gaps in the superheavy region are generally expected to be fragile. In this study, we test the robustness of \begin{document}$ N=152 $\end{document} shell closure in \begin{document}$ N=152 $\end{document} isotones and \begin{document}$ Z=108 $\end{document} shell closure in Hs isotopes by employing an alternative approach where both theoretical analysis and available experimental data are required. Combined with existing experimental measurements on α-decay energies, it is determined that robust \begin{document}$ N=152 $\end{document} neutron shell persists at least in \begin{document}$ Z=101-105 $\end{document} isotopes, and robust \begin{document}$ Z=108 $\end{document} proton shell persists in Hs isotopes with \begin{document}$ N=159,160 $\end{document}. Additionally, the relativistic mean-field model is determined as unable to provide \begin{document}$ N=152 $\end{document} shell. Thus, the conclusion that robust \begin{document}$ N=152 $\end{document} shell exists at least in \begin{document}$ Z=101-105 $\end{document} isotopes, provides crucial benchmarks for constraining effective interactions suitable for superheavy nuclei in nuclear energy-density functional theory in future.
PARTICLES AND FIELDS
Measurement of the integrated luminosity of data samples collected during 2019-2022 by the Belle II experiment
I. Adachi, L. Aggarwal, H. Ahmed, J. K. Ahn, H. Aihara, N. Akopov, A. Aloisio, N. Althubiti, N. Anh Ky, D. M. Asner, H. Atmacan, T. Aushev, V. Aushev, M. Aversano, R. Ayad, V. Babu, H. Bae, S. Bahinipati, P. Bambade, Sw. Banerjee, M. Barrett, J. Baudot, A. Baur, A. Beaubien, F. Becherer, J. Becker, J. V. Bennett, F. U. Bernlochner, V. Bertacchi, M. Bertemes, E. Bertholet, M. Bessner, S. Bettarini, B. Bhuyan, F. Bianchi, L. Bierwirth, T. Bilka, D. Biswas, A. Bobrov, D. Bodrov, J. Borah, A. Boschetti, A. Bozek, P. Branchini, T. E. Browder, A. Budano, S. Bussino, Q. Campagna, M. Campajola, L. Cao, G. Casarosa, C. Cecchi, J. Cerasoli, M.-C. Chang, P. Chang, R. Cheaib, P. Cheema, B. G. Cheon, K. Chilikin, K. Chirapatpimol, H.-E. Cho, K. Cho, S.-J. Cho, S.-K. Choi, S. Choudhury, J. Cochran, L. Corona, J. X. Cui, S. Das, E. De La Cruz-Burelo, S. A. De La Motte, G. de Marino, G. De Nardo, G. De Pietro, R. de Sangro, M. Destefanis, S. Dey, R. Dhamija, A. Di Canto, F. Di Capua, J. Dingfelder, Z. Doležal, I. Domínguez
2025, 49(1): 013001. doi: 10.1088/1674-1137/ad806c
Abstract:
A series of data samples was collected with the Belle II detector at the SuperKEKB collider from March 2019 to June 2022. We determine the integrated luminosities of these data samples using three distinct methodologies involving Bhabha (\begin{document}$e^+e^- \to e^+e^-(n\gamma)$\end{document}), digamma (\begin{document}$e^+e^- \to \gamma\gamma(n\gamma)$\end{document}), and dimuon (\begin{document}$e^+e^- \to \mu^+ \mu^- (n\gamma)$\end{document}) events. The total integrated luminosity obtained with Bhabha, digamma, and dimuon events is (426.88 ± 0.03 ± 2.61) fb−1, (429.28 ± 0.03 ± 2.62) fb−1, and (423.99 ± 0.04 ± 3.83) fb−1, where the first uncertainties are statistical and the second are systematic. The resulting total integrated luminosity obtained from the combination of the three methods is (427.87 ± 2.01) fb−1.
Polarization study of P-wave charmonium radiative decay into a light vector meson at e+e− collider experiment
Yong-Qing Chen, Peng-Cheng Hong, Zhuo Chen, Wei Shan, Wei-Min Song
2025, 49(1): 013002. doi: 10.1088/1674-1137/ad8ba2
Abstract:
In this paper, a formalism is presented for the helicity amplitude analysis of the decays \begin{document}$ \psi(2S) \to $\end{document}\begin{document}$ \gamma_1 \chi_{cJ},\; \chi_{cJ} \to \gamma_2 V (V=\rho^0,\; \phi,\; \omega) $\end{document} (subscripts 1 and 2 are used to distinguish the two radiative photons), and the polarization expressions of the P-wave charmonia \begin{document}$ \chi_{cJ} $\end{document} and the vector mesons \begin{document}$ \rho^0, \phi, \omega $\end{document} for experimental measurements at an electron-positron collider. In addition, we derive formulae for the angular distributions of \begin{document}$ \chi_{c1,2} \to \gamma V $\end{document} to extract the degree of transverse polarization \begin{document}$ P_T $\end{document} of \begin{document}$ e^+ e^- $\end{document} pairs with symmetric beam energy as well as the ratios of two helicity amplitudes x (in \begin{document}$ \chi_{c1} $\end{document} decays) and \begin{document}$ x,\; y $\end{document} (in \begin{document}$ \chi_{c2} $\end{document} decays), which represent the relative magnitudes of transverse to longitudinal polarization amplitude. The results are validated by Monte Carlo simulation. Finally, the statistical sensitivity of \begin{document}$ P_T $\end{document}, x, and y are estimated based on the large \begin{document}$ \psi(2S) $\end{document} data samples collected at current and proposed future \begin{document}$ e^+e^- $\end{document} collider experiments.
Dynamical study of Tss systems using the chiral quark model
Jiazheng Ji, Yuheng Xing, Xinxing Wu, Ning Xu, Yue Tan
2025, 49(1): 013101. doi: 10.1088/1674-1137/ad7c28
Abstract:
Since the discovery of Tcc by LHCb, there has been considerable interest in Tcc and its heavy-flavor partners. However, the study of its strange partner Tss has been largely overlooked. Within the framework of the chiral quark model, we conducted a systematic study of the bound states of Tss based on the Gaussian Expansion Method. We considered all physical channels with 01+, including molecular and diquark structures. Moreover, by considering the coupling between diquarks and molecular states, our calculations allowed us to identify a deep bound state with a bounding energy of 60 MeV primarily composed of KK*. Using the 3P0 model, we calculated the decay width of K* within the KK* bound state, which is approximated as the decay width of the bound state in the Tss system. These results indicate that, owing to the effect of binding energy, the decay width of K* in KK* is approximately 3 MeV smaller than that of K* in vacuum. Additionally, resonance state calculations were performed. We used the real-scaling method to search for possible resonance states in the Tss sysytem. Because of the strong attraction in the [K*]8[K*]8 configuration, four resonance states were found in the vicinity of 2.2−2.8 GeV, predominantly featuring hidden-color structures. The decay widths of these states are less than 10 MeV. We strongly recommend experimental efforts to search for the resonance states in the Tss system predicted by our calculations.
Study of charmonium(-like) mesons under a diabatic approach
Zi-Zhao Zhang, Rong Li, Bo-Chao Liu
2025, 49(1): 013102. doi: 10.1088/1674-1137/ad79d6
Abstract:
In this work, we study the charmonium(-like) spectrum below 4.1 GeV using the diabatic approach, which offers a unified description of conventional and unconventional heavy meson states. Compared to previous studies, we consider a more realistic \begin{document}$c\bar c$\end{document} potential by including the spin-dependent interactions, which allows us to obtain more states and insights into the charmonium spectrum. Based on our calculation, we obtain the masses of the charmonium spectrum, which align well with experimental data. We also present the probabilities of finding various components, i.e., \begin{document}$c\bar c$\end{document} or meson-meson pairs, in these states. Our results support the arguments that \begin{document}$\chi_{c1}(3872)$\end{document}, \begin{document}$\psi(4040)$\end{document}, and \begin{document}$\chi_{c2}(3930)$\end{document} have significant molecular components. In addition, our calculations show that \begin{document}$\chi_{c0}(3860)$\end{document} and \begin{document}$\psi(3770)$\end{document} can be considered as candidates for the charmonium states \begin{document}$\chi_{c0}(2P)$\end{document} and \begin{document}$\psi(1D)$\end{document}, respectively.
Next-to-next-to-leading order QCD ${\otimes }$ EW corrections to Z-boson pair production at electron-positron colliders
Zhe Li, Ren-You Zhang, Shu-Xiang Li, Xiao-Feng Wang, Pan-Feng Li, Yi Jiang, Liang Han, Qing-hai Wang
2025, 49(1): 013103. doi: 10.1088/1674-1137/ad77b4
Abstract:
We present a comprehensive analytic calculation of the next-to-next-to-leading order \begin{document}$ \text{QCD} \otimes \text{EW} $\end{document} corrections to Z-boson pair production at electron-positron colliders. The two-loop master integrals essential to this calculation are evaluated using the differential equation method. In this paper, we detail the formulation and solution of the canonical differential equations for the two-loop three-point master integrals with two on-shell Z-boson external legs and a massive internal quark in the loops. These canonical master integrals are systematically expanded as a Taylor series in the dimensional regulator, \begin{document}$ \epsilon = (4-d)/2 $\end{document}, up to the order of \begin{document}$ \epsilon^4 $\end{document}, with coefficients expressed in terms of Goncharov polylogarithms up to weight four. Upon applying our analytic expressions of these master integrals to the phenomenological analysis of Z-pair production, we observe that the \begin{document}$ {\cal{O}}(\alpha \alpha_s) $\end{document} corrections manifest at a level of approximately one percent when compared to the leading-order predictions, underscoring their significance for comparisons with future high-precision experimental data.
Holographic bottom-up approach to Σ baryons
Xi Guo, Miguel Angel Martin Contreras, Xun Chen, Dong Xiang
2025, 49(1): 013104. doi: 10.1088/1674-1137/ad7d75
Abstract:
In this study, we discuss the description of neutral Σ baryons with \begin{document}$ I(J^P)=1(1/2^+) $\end{document} and \begin{document}$ I(J^P)=1(3/2^+) $\end{document} using two bottom-up approaches: the deformed background and static dilaton models. In both models, we consider a non-linear Regge trajectory extension motivated by the strange nature of Σ baryons. We find that both models describe these systems with an RMS error smaller than 10%. We also perform a configurational entropy calculation in both models to discuss hadronic stability.
Two-zero textures for Dirac neutrinos
Yessica Lenis, R. Martinez-Ramirez, Eduardo Peinado, William A. Ponce
2025, 49(1): 013105. doi: 10.1088/1674-1137/ad9147
Abstract:
We review the two-zero mass matrix textures approach for Dirac neutrinos with the most recent global fit in the oscillation parameters. We found that three of the 15 possible textures are compatible with current experimental data, while the remaining two-zero textures were ruled out. Two textures are consistent with the normal hierarchy of neutrino masses and are CP-conserving, while the other is compatible with both mass orderings and allows for CP violation. We also present the correlations between the oscillation parameters for the allowed two-zero textures.
Supersymmetric hybrid inflation in light of CMB experiments and swampland conjectures
Waqas Ahmed, Shabbar Raza
2025, 49(1): 013106. doi: 10.1088/1674-1137/ad7c27
Abstract:
In this study, we revisit supersymmetric (SUSY) hybrid inflation within the context of considering the latest Cosmic Microwave Background (CMB) observations and swampland conjectures. We demonstrate that SUSY hybrid inflation remains consistent with Planck 2018 data when radiative, soft mass, and supergravity (SUGRA) corrections are applied to the scalar potential. It is commonly perceived that SUSY hybrid inflation with a minimal Kähler potential results in a gauge symmetry breaking scale M of \begin{document}$ {\cal O}(10^{15}) $\end{document} GeV, leading to issues with the proton decay rate. In our analysis, we introduce a novel parameter space that alleviates the proton decay issue by achieving \begin{document}$ M \sim 10^{16} $\end{document} GeV with \begin{document}$ M_{S}^{2}<0 $\end{document} and \begin{document}$ am_{3/2}>0 $\end{document}. This scenario necessitates a soft SUSY breaking scale \begin{document}$ |M_{S}| \gtrsim 10^{6} $\end{document} GeV. Further, we find that the tensor-to-scalar ratio r spans from \begin{document}$ 10^{-16} $\end{document} to \begin{document}$ 10^{-6} $\end{document}, indicating a very small value. This small ratio allows the modified swampland criteria to hold, although satisfying the trans-Planckian censorship conjecture (TCC) remains challenging. To address this, we also explo non-minimal Kähler potentials. By fixing the spectral index at \begin{document}$ n_{S}=0.9665 $\end{document}, consistent with the central value of Planck 2018 data, and setting \begin{document}$ M=2\times 10^{16} $\end{document}GeV, we present our calculations. We show that the canonical measure of primordial gravitational waves, r, for \begin{document}$ M_{S}= $\end{document} 1 TeV, \begin{document}$ m_{3/2}= $\end{document} 1 TeV, and \begin{document}$ \kappa_{S}<0 $\end{document} for \begin{document}$ {\cal{N}}= $\end{document}1 and \begin{document}$ {\cal{N}}= $\end{document}2, ranges from \begin{document}$ 10^{-5} $\end{document} to \begin{document}$ 0.01 $\end{document}, rendering it detectable by Planck and upcoming experiments such as LiteBIRD, Simons Observatory, PRISM, PIXIE, CORE, CMB-S4, and CMB-HD. Additionally, we outline the parametric space and provide benchmark points for the non-minimal case to ensure compatibility with both the modified swampland conjecture and TCC.
Two texture zeros for Dirac neutrinos in a diagonal charged lepton basis
Yessica Lenis, John D. Gómez, William A. Ponce, Richard H. Benavides
2025, 49(1): 013107. doi: 10.1088/1674-1137/ad8d4a
Abstract:
A systematic study of the neutrino mass matrix \begin{document}$M_\nu $\end{document} with two texture zeros in a basis that the charged leptons are diagonal, and under the assumption that neutrinos are Dirac particles is performed. Our study is conducted without any approximation, first analytically and then numerically. Current neutrino oscillation data is used in our analysis. Phenomenological implications of \begin{document}$M_\nu $\end{document} on lepton CP violation and neutrino mass spectrum are explored.
Detailed derivation of the 3P0 strong decay model applied to baryons
T. Aguilar, A. Capelo-Astudillo, M. Conde-Correa, A. Duenas-Vidal, P. G. Ortega, J. Segovia
2025, 49(1): 013108. doi: 10.1088/1674-1137/ad8d4c
Abstract:
By using the\begin{document}$ ^3P_0 $\end{document} pair creation model, we provide a detailed derivation of the transition matrix for a baryon decaying into a meson-baryon system. This analysis was successfully conducted for a meson in [J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)], and we extend the same formalism to the baryon sector, focusing on the \begin{document}$ \Delta(1232)\to \pi N $\end{document} strong decay width because all hadrons involved in the reaction are very well established, the two hadrons in the final state are stable and require no further analysis, all quarks are light and thus equivalent, and the decay width of the process is relatively well measured. Utilizing a very common Rayleigh-Ritz variational method to solve the 2- and 3-body Schödinger bound-state equation in which the hadron’s radial wave functions are expanded in terms of a Gaussian basis, we can relate the expression of the invariant matrix element with the mean-square radii of hadrons involved in the decay. We use their experimental measures in such a way that only the strength of the quark-antiquark pair creation from the vacuum is a free parameter. This is then taken from our previous study on strong decay widths in the meson sector [J. Segovia, D. R. Entem, and F. Fernández, Phys. Lett. B 715, 322 (2012)], and the obtained results are compatible with the experimental results for the calculated \begin{document}$ \Delta(1232)\to \pi N $\end{document} decay width. Despite requiring the calculation of additional baryon strong decays, a feasible avenue towards a unified description of both baryon and meson strong decay widths within a single constituent quark model framework may be attainable. Finally, this research has been developed to lay the foundation for a novel raft of applications to exotic hadrons, i.e., the description of the baryon’s coupling to meson-baryon thresholds, one of the mechanisms that is considered to be responsible for providing either a large renormalization to naive states or genuine dynamically-generated meson-baryon molecules.
Probing axion-like particles in leptonic decays of heavy mesons
Gang Yang, Tianhong Wang, Guo-Li Wang
2025, 49(1): 013109. doi: 10.1088/1674-1137/ad88f9
Abstract:
We study the possibility of finding axion-like particles (ALPs) through the leptonic decays of heavy mesons. The Standard Model (SM) predictions of the branching ratios of the leptonic decays of heavy mesons are less than the corresponding experimental upper limits. This provides some room for the existence of decay channels, of which the ALP is one of the products. Three scenarios are considered: First, the ALP is only coupled to one single charged fermion, namely, the quark, the antiquark, or the charged lepton; second, the ALP is only coupled to quark and antiquark with the same strength; and third, the ALP is coupled to all the charged fermions with the same strength. The constraints of the coupling strength in different scenarios are obtained by comparing the experimental data of the branching ratios of leptonic decays of \begin{document}$B^-$\end{document}, \begin{document}$D^+$\end{document}, and \begin{document}$D_s^+$\end{document} mesons with the theoretical predictions achieved by using the Bethe-Salpeter (BS) method. These constraints are further applied to predict the upper limits of the leptonic decay processes of the \begin{document}$B_c^-$\end{document} meson in which the ALP participates.
Jet tagging with more-interaction particle transformer
Yifan Wu, Kun Wang, Congqiao Li, Huilin Qu, Jingya Zhu
2025, 49(1): 013110. doi: 10.1088/1674-1137/ad7f3d
Abstract:
In this paper, we introduce the More-Interaction Particle Transformer (MIParT), a novel deep-learning neural network designed for jet tagging. This framework incorporates our own design, the More-Interaction Attention (MIA) mechanism, which increases the dimensionality of particle interaction embeddings. We tested MIParT using the top tagging and quark-gluon datasets. Our results show that MIParT not only matches the accuracy and AUC of LorentzNet and a series of Lorentz-equivariant methods, but also significantly outperforms the ParT model in background rejection. Specifically, it improves background rejection by approximately 25% with a signal efficiency of 30% on the top tagging dataset and by 3% on the quark-gluon dataset. Additionally, MIParT requires only 30% of the parameters and 53% of the computational complexity needed by ParT, proving that high performance can be achieved with reduced model complexity. For very large datasets, we double the dimension of particle embeddings, referring to this variant as MIParT-Large (MIParT-L). We found that MIParT-L can further capitalize on the knowledge from large datasets. From a model pre-trained on the 100M JetClass dataset, the background rejection performance of fine-tuned MIParT-L improves by 39% on the top tagging dataset and by 6% on the quark-gluon dataset, surpassing that of fine-tuned ParT. Specifically, the background rejection of fine-tuned MIParT-L improves by an additional 2% compared to that of fine-tuned ParT. These results suggest that MIParT has the potential to increase the efficiency of benchmarks for jet tagging and event identification in particle physics.
Study of the semileptonic decays ${{\boldsymbol\Upsilon}({\bf 1}{\boldsymbol S}){\bf\to}{\boldsymbol B}_{(\boldsymbol c)}{\boldsymbol\ell}\bar{\boldsymbol\nu}_{\boldsymbol\ell}} $
C. T. Tran, M. A. Ivanov, P. Santorelli, H. C. Tran
2025, 49(1): 013111. doi: 10.1088/1674-1137/ad83ab
Abstract:
We study the exclusive semileptonic decays \begin{document}$ \Upsilon(1S)\to B_{(c)}\ell\bar{\nu}_\ell $\end{document}, where \begin{document}$ \ell = e,\mu,\tau $\end{document}. The relevant hadronic form factors are calculated using the covariant confined quark model developed previously by our group. We predict the branching fractions \begin{document}$ \mathcal{B}(\Upsilon(1S)\to B_{(c)}\ell\bar{\nu}_\ell) $\end{document} to be of the order of \begin{document}$ 10^{-13} $\end{document} and 10−10 for the case of B and \begin{document}$ B_c $\end{document}, respectively. Our predictions agree well with other theoretical calculations. We also consider the effects of possible new physics in the case of \begin{document}$ \Upsilon(1S)\to B_c\tau\bar{\nu}_\tau $\end{document} and show that the branching fraction of this decay can be enhanced by an order of magnitude using constraints from the \begin{document}$ B\to D^{(*)}\ell\bar{\nu}_\ell $\end{document} and \begin{document}$ B_c\to J/\psi\ell \bar{\nu}_\ell $\end{document} experimental data.
Exotic hybrid pseudopotentials at finite temperature and chemical potential
Le Zhang, Fei-Yang Cai, Xun Chen
2025, 49(1): 013112. doi: 10.1088/1674-1137/ad8ec4
Abstract:
Using gauge/gravity duality, we studied the exotic hybrid pseudopotentials at finite temperature and chemical potential. The Σ hybrid meson can be described by a model including an object called "defect'' on a string linking the quark and antiquark. The \begin{document}$ \Sigma_u^- $\end{document} hybrid potential at zero temperature and chemical potential was first proposed by Andreev and is perfectly described. In this study, we extended the aforementioned model to finite chemical potential and compared the separate distance and pseudopotentials of \begin{document}$ \Sigma_g^+ $\end{document} and \begin{document}$ \Sigma_u^- $\end{document}. Unlike the \begin{document}$ \Sigma_g^+ $\end{document} ground state, the \begin{document}$ \Sigma_u^- $\end{document} hybrid pseudopotentials no longer exhibit Coulomb-like behavior at short distances. In addition, temperature and chemical potential have a significant impact on the \begin{document}$ \Sigma_u^- $\end{document} hybrid pseudopotentials. The screen distances and hybrid pseudopotentials of \begin{document}$ \Sigma_u^- $\end{document} significantly decrease when increasing temperature and chemical potential. We represented the melting diagram of \begin{document}$ \Sigma_g^+ $\end{document} and \begin{document}$ \Sigma_u^- $\end{document} in the \begin{document}$ T- \mu $\end{document} plane and confirmed that the quark-antiquark pair in \begin{document}$ \Sigma_u^- $\end{document} excited state is easier to melt than that in \begin{document}$ \Sigma_g^+ $\end{document} ground state.
NUCLEAR PHYSICS
Systematic study of cross section for proton-induced reactions on neodymium up to 65 MeV using TALYS-1.96 code
A. Saha
2025, 49(1): 014101. doi: 10.1088/1674-1137/ad7c35
Abstract:
A systematic study was conducted on the theoretical estimation of the nuclear cross sections of charged particle induced reactions on rare earth nuclei. The production cross sections of the 150,149,148,146,144,143,141Pm and 149,147Nd nuclei were calculated theoretically via proton induced reactions on neodymium using TALYS (version 1.96) code in the default mode, with different combinations of nuclear models as well as adjusted nuclear model parameters from the reaction threshold up to a proton energy of 65 MeV. The theoretically computed results were compared with the experimental results taken from the EXFOR database and literature reported by various research groups. Moreover, the effects of various level density models, preequilibrium models, optical model potentials, and gamma strength functions on the cross section calculation were considered. This theoretical analysis will help elucidate the theory of nuclear reaction models and improve the evaluated nuclear data libraries.
A novel approach for the anomalous collectivity in neutron-deficient Os isotopes
Wei Teng, Yu Zhang, Chong Qi
2025, 49(1): 014102. doi: 10.1088/1674-1137/ad7c29
Abstract:
An algebraic model with three-body boson interactions is proposed to incorporate the different quadrupole modes in nuclear collectivity. It is shown that the recently observed anomalous collective structure characterized by \begin{document}$B_{4/2}=B(E2;4_1\rightarrow2_1)/B(E2;2_1\rightarrow0_1) <1.0$\end{document} and \begin{document}$R_{4/2}= E(4_1)/E(2_1)\geq2.0$\end{document}, which cannot yet be explained by any other microscopic nuclear models, naturally emerges in the present model due to the inclusion of triaxial rotor modes. This description is further extended to describe odd-A nuclei by including the coupling to the Fermion degree of freedom. This allows us to give a unified explanation of the anomalous \begin{document}$B(E2)$\end{document}strengths in both even-even and even-odd systems, which indicate different behaviors. As examples, the model is applied to describe the spectroscopy and \begin{document}$E2$\end{document} transition properties of \begin{document}$^{168,169,170,171}$\end{document}Os. All recent measurements of these isotopes can be well reproduced on the same footing, which suggests that the anomalous collectivity persists even in odd-A systems.
Octupole correlations in stable nucleus 153Eu within reflection-asymmetric particle rotor model
Yuanyuan Wang, Shuangquan Zhang
2025, 49(1): 014103. doi: 10.1088/1674-1137/ad78d6
Abstract:
The observed low-lying \begin{document}$K=5/2^\pm$\end{document} positive- and negative-parity bands in the stable nucleus 153Eu are investigated using the reflection-asymmetric triaxial particle rotor model. The experimental energy spectra, energy staggering parameters, and intraband \begin{document}$E2$\end{document} and \begin{document}$M1$\end{document} transition probabilities are well reproduced. The calculated interband \begin{document}$B(E1)$\end{document} values are found to depend sensitively on the octupole deformation parameter \begin{document}$\beta_{30}$\end{document}, although the energy spectra and intraband \begin{document}$E2$\end{document} and \begin{document}$M1$\end{document} transitions can be reproduced without the octupole degree of freedom. The observed enhanced \begin{document}$E1$\end{document} transition probabilities can be reproduced with \begin{document}$\beta_{30}=0.05$\end{document}. The detailed analysis of the intrinsic wave functions shows these nearly degenerate positive- and negative-parity bands are built on two individual proton configurations, i.e., dominated by \begin{document}$\pi g_{7/2}[\Omega=5/2]$\end{document} and \begin{document}$\pi h_{11/2}[\Omega=5/2]$\end{document}, respectively, which differs from the parity doublet bands built on a single parity-mixed configuration.
Analysis of transverse momentum spectra of protons, deuterons, and tritons in symmetric heavy-ion collisions at${ \sqrt {{\boldsymbol s_{_{\boldsymbol NN}}}} }$ = 200 GeV at the RHIC
Waqas Ahmad, Ihsan Ullah, Ali Zaman, Imran Khan, Akhtar Iqbal, Abdul Qudus, Sana Ullah, Naseeb Ullah, Muhammad Ramzan
2025, 49(1): 014104. doi: 10.1088/1674-1137/ad83a7
Abstract:
The blast wave model with Tsallis statistics is used to analyze the transverse momentum spectra of protons (p), deuterons (d), and tritons (t) in \begin{document}$\sqrt{{s}_{_{NN}}}$\end{document} = 200 GeV gold-gold (Au-Au) collisions at the RHIC in various centrality bins. In particular transverse momentum ranges, the model results closely match experimental data from the PHENIX (p) and STAR (d and t) collaborations. The data are compared with those of protons obtained in Cu+Cu collisions and deuterons and tritons in Ru+Ru collisions at a center of mass energy of 200 GeV from the STAR collaboration. Particle spectra are used to derive the kinetic freeze-out temperatures, transverse flow velocities, and freeze-out volumes. According to the findings, the kinetic freeze-out temperature increases from the central to peripheral collisions. In this transition, the transverse flow velocity and freeze-out volume both decrease. For the collisions of both collaborations, this study reveals mass-dependent kinetic freeze-out temperature and differential volume possibilities. Overall, the non-extensivity parameter q decreases with increasing centrality of the studied heavy-ion collisions, and heavier mass particles have smaller values of q, which implies higher degrees of thermalization and equilibrium in more central collisions and for heavier particles.
${\mathcal{{{R}}}^{\boldsymbol{2}}}$ curvature-squared corrections on Langevin diffusion coefficients
Qi Zhou, Ben-Wei Zhang
2025, 49(1): 014105. doi: 10.1088/1674-1137/ad8420
Abstract:
The effect of finite coupling corrections to the Langevin diffusion coefficients on a moving heavy quark in the Super Yang-Mills plasma was investigated. These corrections are related to curvature squared corrections in the corresponding gravity sector. We compared the results of both longitudinal and perpendicular Langevin diffusion coefficients with those for \begin{document}$\mathcal{N}$\end{document}=4 Super Yang-Mills plasma. It was observed that the curvature-squared corrections influence the Langevin diffusion coefficients, and the corrections for both Langevin diffusion coefficients demonstrate the dependence on the velocity of the moving heavy quark and the specifics of the higher derivative correction. In addition, we conducted calculations for the Langevin diffusion coefficients of a moving heavy quark within the Gauss-Bonnet background.
Solving the relativistic Hartree-Bogoliubov equation with the finite-difference method
Yiran Wang, Xiaojie Cao, Jinniu Hu, Ying Zhang
2025, 49(1): 014106. doi: 10.1088/1674-1137/ad806f
Abstract:
The relativistic Hartree-Bogoliubov (RHB) theory is a powerful tool for describing exotic nuclei near drip lines. The key technique is to solve the RHB equation in the coordinate space to obtain the quasi-particle states. In this paper, we solve the RHB equation with the Woods-Saxon-type mean-field and Delta-type pairing-field potentials by using the finite-difference method (FDM). We inevitably obtain spurious states when using the common symmetric central difference formula (CDF) to construct the Hamiltonian matrix, which is similar to the problem resulting from solving the Dirac equation with the same method. This problem is solved by using the asymmetric difference formula (ADF). In addition, we show that a large enough box is necessary to describe the continuum quasi-particle states. The canonical states obtained by diagonalizing the density matrix constructed by the quasi-particle states are not particularly sensitive to the box size. Part of the asymptotic wave functions can be improved by applying the ADF in the FDM compared to the shooting method with the same box boundary condition.
Spherical-like spectra for the description of the normal states of 108-120Cd in the SU3-IBM and the $ {{\boldsymbol Q}_{\bf 2_{1}^{\bf +}}} $ anomaly
Tao Wang, Xin Chen, Yu Zhang
2025, 49(1): 014107. doi: 10.1088/1674-1137/ad7d76
Abstract:
The Cd puzzle implies that the phonon excitation of a spherical nucleus should be questioned and refuted. To understand the newly and experimentally discovered spherical-like γ-soft mode, the SU3-IBM was recently proposed. In this study, the evolutions of the normal states in \begin{document}$^{108-120}$\end{document}Cd are investigated and compared with the experimental results. To better explain the nearly zero B(E2) values between the \begin{document}$0_{2}^{+}$\end{document} and \begin{document}$2_{1}^{+}$\end{document} states, SU(3) higher-order interactions except for the SU(3) second-order and third-order Casimir operators are also considered in detail. We find that the results of theoretical fitting and experimental data agree well with simple parameter selection, and the spherical-like spectra truly exist. The deficiency may arise from the lack of configuration mixing. The realistic spectra characteristics of the spherical-like spectra are found for \begin{document}$^{118,120}$\end{document}Cd, and the electric quadrupole moments of the \begin{document}$2_{1}^{+}$\end{document} state are predicted. The \begin{document}$Q_{2_{1}^{+}}$\end{document} anomaly in \begin{document}$^{108-116}$\end{document}Cd is also discussed.
Analytic continuation in the coupling constant for resonances in ${{}^{{\boldsymbol{9}}}_{{\boldsymbol{\Lambda}}}}$Be
Hantao Zhang, Dong Bai, Zhongzhou Ren
2025, 49(1): 014108. doi: 10.1088/1674-1137/ad88fa
Abstract:
The application scope of the analytic continuation in the coupling constant (ACCC) can be extended to the exchange parameters of the effective nucleon-nucleon interaction in the microscopic cluster model. Based on such an exchange parameter dependent ACCC (abbreviated as EPD-ACCC), we examine the \begin{document}$ {}_{\Lambda}^9 $\end{document}Be system in the framework of the \begin{document}$ \alpha+\alpha+\Lambda $\end{document} microscopic cluster model. The particle emission from excited states of \begin{document}$ \alpha+\alpha+\Lambda $\end{document}are investigated, and the corresponding resonant energies are obtained via EPD-ACCC. Furthermore, the complex scaling method (CSM) is applied for comparison. A good agreement between these two theoretical approaches is obtained. This study demonstrates EPD-ACCC to be a reliable method for estimating multi-cluster resonances in light hypernuclei.
Modeling net-charge fluctuations in heavy-ion collisions at the LHC
G. O. Ambaryan, A. S. Chernyshov, G. Kh. Eyyubova, V. L. Korotkikh, I. P. Lokhtin, S. V. Petrushanko, A. M. Snigirev, E. E. Zabrodin
2025, 49(1): 014109. doi: 10.1088/1674-1137/ad8a39
Abstract:
Analysis of Pb+Pb data for net-charge fluctuations at LHC energies using the HYDJET++ model is presented. The strongly intensive quantities D and Σ were used to remove the effects related to system volume fluctuations. We employed two versions of HYDJET++ for the analysis. The first one is the standard or default version, whereas the second one is a modification that takes into account explicit event-by-event conservation of the electric net-charge of produced particles. The inclusion of the canonical net-charge conservation in the model allows for better description of the experimental data obtained by the ALICE and CMS Collaborations. A comparison with calculations from other models is also presented.
PARTICLE AND NUCLEAR ASTROPHYSICS AND COSMOLOGY
Is dark energy necessary for the sustainability of traversable wormholes?
Ayan Banerjee, Sudan Hansraj, Anirudh Pradhan, Abdelghani Errehymy
2025, 49(1): 015101. doi: 10.1088/1674-1137/ad73ad
Abstract:
Dark energy is typically the principal component needed for the traversability of wormholes (WH), as it provides the negative gravity effect required to keep the throat open. However, can this be achieved without dark energy? It turns out that if we couple the trace of energy-momentum with the standard Einstein-Hilbert Lagrangian and utilize a specific equation of state (EoS), dark energy may be obviated. The Casimir stress energy is known to result in the violation of the null energy condition (NEC) on the energy momentum tensor. This phenomenon makes such an EoS an ideal candidate for generating traversable WH geometries. The laboratory proven phenomenon provides a natural mechanism to sustain an open WH throat without relying on dark energy. Therefore, we generate two classes of WH solutions using this in energy-momentum trace-coupling gravity. For the specific choice of the Casimir EoS relating the energy-momentum tensor components [Kar and Sahdev: Phys. Rev. D 52, 2030 (1995)] and different choices of redshift functions, we determine the WH geometry completely. The obtained WH solutions violate the NECs, and all qualitative constraints demanded for physically realizable WHs are satisfied. This is demonstrated via graphical plots for a suitably chosen range of coupling parameter values. Furthermore, our study investigates the repulsive effect of gravity, revealing that its presence leads to a negative deflection angle for photons traveling along null geodesics. Notably, we observe a consistent pattern of negative values for the deflection angle across all values of \begin{document}$ r_0$\end{document} in the three scenarios considered, thus indicating the clear manifestation of the repulsive gravity effect. All of this is possible without invoking the existence of dark energy.
Quark stars in f(R, T) gravity: mass-to-radius profiles and observational data
Ayan Banerjee, İzzet Sakallı, B. Dayanandan, Anirudh Pradhan
2025, 49(1): 015102. doi: 10.1088/1674-1137/ad86af
Abstract:
This study explores the \begin{document}$f(R,T)$\end{document} gravity theory, which introduces a coupling between matter and curvature, through the simplest linear functional form \begin{document}$f(R,T)= R + 2\beta T$\end{document}. We derive the modified Einstein field equations and conservation equations for this theory and then apply this framework to study the structural properties of quark stars (QSs) composed of interacting quark matter, considering perturbative QCD corrections and color superconductivity. By solving the modified Tolman-Oppenheimer-Volkoff equations, we investigate the mass-radius relation, stability criteria, and energy conditions of QSs. Our results indicate that the \begin{document}$f(R,T)$\end{document} gravity significantly influences the properties of QSs, leading to deviations from General Relativity. The analysis is consistent with recent observational data, suggesting that the modified gravity framework could provide viable models for the study of compact stars.
Phase space analysis of interacting and non-interacting models in f(Q, C) gravity
Amit Samaddar, Singh S. Surendra
2025, 49(1): 015103. doi: 10.1088/1674-1137/ad7f3f
Abstract:
Using a dynamical system method, we study a Friedmann-Robertson-Walker (FRW) cosmological model within the context of \begin{document}$f(Q, C)$\end{document} gravity, where \begin{document}$Q$\end{document} is the non-metricity scalar and \begin{document}$C$\end{document} represents the boundary term, considering both interacting and non-interacting models. A set of autonomous equations is derived, and solutions are calculated accordingly. We assess the critical points obtained from these equations, identify their characteristic values, and explore the physical interpretation of the phase space for this system. Two types of \begin{document}$f(Q, C)$\end{document} are assumed: \begin{document}$({\rm{i}})$\end{document} \begin{document}$f(Q, C)=Q+\alpha Q+\beta C {\rm{log}}C$\end{document} and \begin{document}$({\rm{ii}})$\end{document} \begin{document}$f(Q, C)=Q+\alpha Q+\frac{\beta}{C}$\end{document}, where \begin{document}$\alpha$\end{document} and \begin{document}$\beta$\end{document} are the parameters. In Model I, we obtain two stable critical points, whereas in Model II, we identify three stable critical points for both interacting and non-interacting models. We examine the behavior of phase space trajectories at every critical point. We calculate the values of the physical parameters for both systems at each critical point, indicating the accelerated expansion of the Universe.
Cosmic distance duality relation in light of time-delayed strong gravitational lensing
Li Tang, Hai-Nan Lin, Ying Wu
2025, 49(1): 015104. doi: 10.1088/1674-1137/ad83a8
Abstract:
The cosmic distance duality relation (DDR), which links the angular-diameter and luminosity distances, is a cornerstone in modern cosmology. Any deviation from DDR may indicate new physics beyond the standard cosmological model. In this study, we used four high-precision time-delayed strong gravitational lensing (SGL) systems provided by H0LiCOW to test the validity of DDR. To this end, we directly compared the angular-diameter distances from these SGL systems with the luminosity distances from the latest Pantheon+ compilation of SNe Ia. To reduce the statistical errors arising from redshift matching, a Gaussian process method was applied to reconstruct the distance-redshift relation from the Pantheon+ dataset. We parameterized the possible violation of DDR in three different models. All results confirm the validity of DDR at \begin{document}$ 1\sigma$\end{document} confidence level. Additionally, Monte Carlo simulations based on the future LSST survey indicated that the precision of DDR could reach the \begin{document}$ 10^{-2}$\end{document} level with 100 SGL systems.
Mass ladder operators and quasinormal modes of the static BTZ-like black hole in Einstein-bumblebee gravity
Fengkai Ge, Qiyuan Pan, Songbai Chen, Jiliang Jing
2025, 49(1): 015105. doi: 10.1088/1674-1137/ad83a9
Abstract:
We investigate mass ladder operators for the static BTZ-like black hole in Einstein-bumblebee gravity and probe the quasinormal frequencies of the mapped modes using mass ladder operators for a scalar perturbation under Dirichlet and Neumann boundary conditions. We find that the mass ladder operators depend on the Lorentz symmetry breaking parameter, and the imaginary parts of the frequencies shifted by the mass ladder operators increase with the increase in the Lorentz symmetry breaking parameter under the two boundary conditions. Note that, under the Neumann boundary condition, the mapped modes caused by the mass ladder operator \begin{document}$ D_{0,k_+}$\end{document}are unstable. Moreover, the mass ladder operators do not change the Breitenlohner-Freedman bound for the scalar modes, as in the case of the usual BTZ black hole. These results could aid us in further understanding the conformal symmetry and Lorentz symmetry breaking in Einstein-bumblebee gravity.
Phase transition in modified thermodynamics of Kerr-AdS black holes
Qin Liu, Xiaoning Wu, Xiao Zhang
2025, 49(1): 015106. doi: 10.1088/1674-1137/ad8a3a
Abstract:
In this study, we investigate the critical phenomena of Kerr-AdS black holes under the modified first law of thermodynamics. Specifically, we considered modified black hole thermodynamics that exhibit a van der Waals-like phase structure. All critical exponents were calculated, and then, a swallowtail diagram of free energy was plotted. Comparing with existing results, the main difference is the correspondence between the thermal quantities of Kerr-AdS black holes and the van der Waals system. In a previous study [Y. D. Tsai, X. N. Wu, and Y. Yang, Phys. Rev. D 85 044005 (2012)], the correspondence was \begin{document}$(\Omega_{H},J)$\end{document}\begin{document}$\rightarrow(V,P)$\end{document}, while in our study, the correspondence was\begin{document}$(J,\hat{\Omega}_{H})$\end{document}\begin{document}$\rightarrow(V,P)$\end{document}. This difference was owing to the rotating effect. The modified black hole thermodynamics were associated with rotating observers. The free energy in such a reference contains extra rotating energy, which induces a Legendre transformation in the \begin{document}$(\hat{\Omega}_{H},J)$\end{document} cross-section, causing the difference in correspondence.
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