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Analysis of Pcs(4338) and related pentaquark molecular states via QCD sum rules
Xiu-Wu Wang, Zhi-Gang Wang
Published: , doi: 10.1088/1674-1137/ac9aab
In this study, we tentatively identify $ P_{cs}(4338) $ as the $ \bar{D}\Xi_c $molecular state and distinguish the isospins of current operators to explore in detail the$ \bar{D}\Xi_c $, $ \bar{D}\Lambda_c $, $ \bar{D}_s\Xi_c $, $ \bar{D}_s\Lambda_c $, $ \bar{D}^*\Xi_c $, $ \bar{D}^*\Lambda_c $, $ \bar{D}^*_s\Xi_c $, and $ \bar{D}^*_s\Lambda_c $ molecular states without strange, with strange, and with double strange in the framework of QCD sum rules. The present exploration favors identifying $ P_{cs}(4338) $ ($ P_{cs}(4459) $) as the $ \bar{D}\Xi_c $ ($ \bar{D}^*\Xi_c $) molecular state with the spin-parity $ J^P={\dfrac{1}{2}}^- $ ($ {\dfrac{3}{2}}^- $) and isospin $ (I,I_3)=(0,0) $, and the observation of their cousins with the isospin $ (I,I_3)=(1,0) $ in the $ J/\psi\Sigma^0/\eta_c\Sigma^0 $ invariant mass distributions would decipher their inner structures.
Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model
Narmin Huseynova, Shahin Mamedov, Jannat Samadov
Published: , doi: 10.1088/1674-1137/ac957a
We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist $\tau=6$ vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.
Thermodynamics of black holes in the quintessential phase space
Guan-Ru Li, Sen Guo, Guo-Ping Li
Published: , doi: 10.1088/1674-1137/ac9b2b
Considering that the negative pressure of the accelerated expansion of the universe results from the cosmological constant or the dark energy quintessence, we use the dark energy quintessence to construct the "quintessential" phase space. In contrast to the previous discussion in which the cosmological constant is considered as the black hole (BH) phase transition pressure, in this analysis, we believe that the pressure results from quintessence. The characteristics of critical behavior, Gibbs free energy, and temperature behavior in quintessential phase space are investigated. We observe that the phase transition belongs to van der Waals phase transition within$ -1 <\omega_{\rm q}<-2/3 $. If $ \omega_{\rm q} $is within (–2/3, –1/3), the phase transition loses the large BH phase transition characteristics, which is caused by the later stage of the phase transition being completely dominated by quintessence dark energy with negative pressure. These results suggest that the quintessential phase space can be constructed with the pressure from the thermal quintessence, and it can be used as a new probe to explore the thermodynamics of BHs.
Center of mass motion in bag model
Chia-Wei Liu, Chao-Qiang Geng
Published: , doi: 10.1088/1674-1137/ac9de8
Despite its success with mass spectra, the reputation of the bag model has been marred by embarrassment of the center of mass motion. It leads to severe theoretical inconsistencies. For instance, the masses and the decay constants would no longer be independent of the momentum. In this work, we provide a systematic approach to resolving this problem. Our framework can consistently compute the meson decay constants and baryon transition form factors. Notably, the form factors in the neutron β decays do not depend on any free parameters and are determined to be$ F^V_1 =1 $ and $ F^A_1 = 1.31 $ or $ F_1^A/F_1^V= 1.31 $, which is close to the experimental value of $ F^A_1/F^V_1 = 1.27 $. In addition, we find that $ {\cal B} (\Lambda_b \to \Lambda \gamma) = (6.8 \pm 3.3 ) \times 10^{-6} $, which agrees to the experimental value of $ (7.1\pm 1.7)\times 10^{-6} $.
Primordial black hole from the running curvaton
Lei-Hua Liu
Published: , doi: 10.1088/1674-1137/ac9d28
In light of our previous study [Chin. Phys. C 44(8), 085103 (2020)], we investigate the possibility of the formation of a primordial black hole in the second inflationary process induced by the oscillation of the curvaton. By adopting the instability of the Mathieu equation, one can utilize the δ function to fully describe the power spectrum. Owing to the running of the curvaton mass, we can simulate the value of the abundance of primordial black holes covering almost all of the mass ranges. Three special cases are given. One case may account for dark matter because the abundance of a primordial black hole is approximately 75% . As late times, the relic of exponential potential may be approximated to a constant of the order of a cosmological constant, which is dubbed as the role of dark energy. Thus, our model could unify dark energy and dark matter from the perspective of phenomenology. Finally, it sheds new light on exploring Higgs physics.
Smuon in the NMSSM confronted with the muon g–2 anomaly and SUSY searches
Kun Wang, Jingya Zhu
Published: , doi: 10.1088/1674-1137/ac9896
Motivated by recent supersymmetry (SUSY) search results, which prefer most SUSY particles to be heavy, and the muon g–2 anomaly, which prefers colorless SUSY particles to be light, we explore the status of a light smuon (the SUSY partner of a left-handed muon lepton) in the next-to-minimal supersymmetric standard model (NMSSM). Assuming colored SUSY particles to be heavy, and considering numerous experimental constraints, including muon g-2, SUSY searches, and dark matter, we scan the parameter space in the NMSSM with $ \mathbb{Z}_3 $-symmetry and check the status of colorless SUSY particles and their possible mass order, paying special attention to the smuon. After calculations and discussions, we find that the surviving samples can be divided into several scenarios, where the mass region and decay information of the smuon are given. Overall, the smuon mass can be approximately 0.1~1.8 TeV. These results may be useful for smuon searches at the LHC and future colliders.
Production of neutron-deficient nuclei around N = 126 by proton-induced spallation
Xin Lei, Erxi Xiao, Yujie Feng, Yingge Huang, Long Zhu, Jun Su
Published: , doi: 10.1088/1674-1137/ac9601
Many isotopes of Np, Pu, Am, and Cm around the N = 126 shell still have not been produced in the laboratory. This study aims to investigate the cross sections and yields of the neutron-deficient nuclei of Np, Pu, Am, and Cm produced in the proton-induced spallations of transuranium elements. The isospin-dependent quantum molecular dynamics (IQMD) model is applied to study the dynamical process of reaction, and the subsequent decay process is simulated by the GEMINI++ model. The IQMD-GEMINI++ model is applied to calculate the cross section, kinetic energy, and angular distribution of the isotopic productions around N = 126. The Lindhand, Scharff, and Schiott theory is applied to calculate the energy loss of different heavy nuclei in the target material. A comparison between the data and the calculations shows that the IQMD-GEMINI++ model can reproduce the production cross sections of the neutron-deficient nuclei in spallation within approximately 1.5 orders of magnitude. The maximum cross section of the undiscovered isotopes of Np, Pu, Am, and Cm is about 10−5 mb, while the kinetic energies of the productions are all less than 16 MeV. The angular distribution shows that the emission direction of production is mostly at a backward angle. The range of production in the target is within the range of 10−7 to 10−5 cm. This range is the effective target thickness for the online identification of undiscovered isotopes. Based on the effective thickness of the target and assuming an intensity of 120 μA for the proton beam, the yields of the undiscovered neutron-deficient nuclei are calculated. Productions of the undiscovered isotopes of Np, Pu, Am, and Cm by the proton-induced spallations of transuranium elements are feasible. However, experimental techniques for online identification of neutron-deficient nuclei produced in proton-induced spallation should be developed.
Systematic calculations of cluster radioactivity half-lives in trans-lead nuclei
Lin-Jing Qi, Dong-Meng Zhang, Song Luo, Xiao-Hua Li, Xi-Jun Wu, Chun-Tian Liang
Published: , doi: 10.1088/1674-1137/ac94bd
In the present work, based on the Wentzel-Kramers-Brillouin (WKB) theory, considering the cluster preformation probability ($ P_{c} $), we systematically investigate the cluster radioactivity half-lives of 22 trans-lead nuclei ranging from 221Fr to 242Cm. When the mass number of the emitted cluster $ A_{c} $ $ < $ 28, $P_{c} $ is obtained by the exponential relationship of $ P_{c} $ to the α decay preformation probability ($ P_{\alpha} $) proposed by R.Blendowskeis $ et $ $ al. $ [Phys. Rev. Lett. 61, 1930 (1988)], while $ P_{\alpha} $ is calculated through the cluster-formation model (CFM). When $ A_{c} $ $ \ge $ 28, $ P_{c} $ is calculated through the charge-number dependence of $ P_{c} $ on the decay products proposed by Ren $ et $ $ al. $ [Phys. Rev. C 70, 034304 (2004)]. The half-lives of cluster radioactivity have been calculated by the density-dependent cluster model [Phys. Rev. C 70, 034304 (2004)] and by the unified formula of half-lives for alpha decay and cluster radioactivity [Phys. Rev. C 78, 044310 (2008)]. For comparison, a universal decay law (UDL) proposed by Qi $ et $ $ al. $ [Phys. Rev. C 80, 044326 (2009)], a semi-empirical model for both α decay and cluster radioactivity proposed by Santhosh [J. Phys. G: Nucl. Part. Phys. 35, 085102 (2008)], and a unified formula of half-lives for alpha decay and cluster radioactivity [Phys. Rev. C 78, 044310 (2008)] are also used. The calculated results of our work, Ni's formula , and the UDL can well reproduce the experimental data and are better than those of Santhosh's model. In addition, we extend this model to predict the half-lives for 51 nuclei, whose cluster radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020.
Surface geometry and shadow of a Schwarzschild black hole with a halo
Mingzhi Wang, Guanghai Guo, Songbai Chen, Jiliang Jing
Published: , doi: 10.1088/1674-1137/ac94bc
We studied the surface geometry and shadows of a Schwarzschild black hole with a halo containing quadrupolar and octopolar terms. It was found that the quadrupole term causes a Schwarzschild black hole to be prolate at the quadrupole strength $ {\cal{Q}}<0 $ and oblate at $ {\cal{Q}}>0 $, and the octopole term causes to the shadow stretch upward at the octopolar strength ngth $ {\cal{O}}<0 $ and downward at $ {\cal{O}}>0 $. The shadow of a Schwarzschild black hole with a halo stretches and squeezes along the horizontal direction at $ {\cal{Q}}<0 $ and $ {\cal{Q}}>0 $, respectively. Meanwhile, the black hole shadow shifts upward at $ {\cal{O}}<0 $ and downward at $ {\cal{O}}>0 $. We present the light rays that form the shadow boundary to explain the emergence of the extraordinary patterns of the black hole shadow with quadrupole and octopole terms. From the observable width W, height H, oblateness K, and distortion parameter $ \delta_{c} $ of the black hole shadow, we can determine the quadrupole and octopolar strengths of a Schwarzschild black hole with a halo. Our results show that the quadrupolar and octopolar terms yield a series of interesting patterns for the shadow of a Schwarzschild black hole with a halo.
Investigating S-wave bound states composed of two pseudoscalar mesons
Zi-Long Li, Xing-Yue Tan, Zhu-Feng Zhang, Zhen-Yang Wang, Xin-Heng Guo
Published: , doi: 10.1088/1674-1137/ac93ed
In this study, we systematically investigated two-pseudoscalar meson systems with the Bethe-Salpeter equation in the ladder and instantaneous approximations. By solving the Bethe-Salpeter equation numerically with the kernel containing the one-particle exchange diagrams, we found that the $ K\bar{K} $, $ DK $, $ B\bar{K} $, $ D\bar{D} $, $ B\bar{B} $, $ BD $, $ D\bar{K} $, $ BK $, and $ B\bar{D} $ systems with $ I=0 $ can exist as bound states. We also studied the contributions from heavy meson ($ J/\psi $ and $\Upsilon $) exchanges and found that the contributions from heavy meson exchanges cannot be ignored.
Insights into the nature of X(3872) through B meson decays
Zhi-Qing Zhang, Zhi-Lin Guan, Yan-Chao Zhao, Zi-Yu Zhang, Zhi-Jie Sun, Na Wang, Xiao-Dong Ren
Published: , doi: 10.1088/1674-1137/ac945a
We study the $ B_{c,u,d}\to X(3872)P $ decays in the perturbative QCD (PQCD) approach, involving the puzzling resonance $ X(3872) $, where P represents a light pseudoscalar meson (K or π). Assuming $ X(3872) $ to be a $ 1^{++} $ charmonium state, we obtain the following results. (a) The branching ratios of the $ B^+_c\to X(3872)\pi^+ $ and $ B^+_c\to X(3872) K^+ $ decays are consistent with the results predicted by the covariant light-front approach within errors; however, they are larger than those given by the generalized factorization approach. (b) The branching ratio of the $ B^+\to X(3872)K^+ $ decay is predicted as $ (3.8^{+1.1}_{-1.0})\times10^{-4} $, which is smaller than the previous PQCD calculation result but still slightly larger than the upper limits set by Belle and BaBar. Hence, we suggest that the$ B^{0,+}\to X(3872)K^{0,+} $ decays should be precisely measured by the LHCb and Belle II experiments to help probe the inner structure of $ X(3872) $. (c) Compared with the $ B_{u,d}\to X(3872)K $decays, the $ B_{u,d}\to X(3872)\pi $ decays have significantly smaller branching ratios, which drop to values as low as $ 10^{-6} $. (d) The direct CP violations of these considered decays are small ($ 10^{-3}\sim 10^{-2} $) because the penguin contributions are loop suppressed compared to the tree contributions. The mixing-induced CP violation of the $ B\to X(3872)K^0_S $ decay is highly consistent with the current world average value $ \sin2\beta=(69.9\pm1.7)$%. Experimentally testing the results for the branching ratios and CP violations, including the implicit $S U(3)$ and isospin symmetries of these decays, helps probe the nature of $ X(3872) $.
Compact stars admitting Finch-Skea symmetry in the presence of various matter fields
Oleksii Sokoliuk, Alexander Baransky, P.K. Sahoo
Published: , doi: 10.1088/1674-1137/ac9603
In the present study, we investigate the anisotropic stellar solutions admitting Finch-Skea symmetry (viable and non-singular metric potentials) in the presence of some exotic matter fields, such as Bose-Einstein Condensate (BEC) dark matter, the Kalb-Ramond fully anisotropic rank-2 tensor field from the low-energy string theory effective action, and the gauge field imposing $ U(1) $ symmetry. Interior spacetime is matched with both Schwarzchild and Reissner-Nördstrom vacuum spacetimes for BEC, KB, and gauge fields. In addition, we study the energy conditions, Equation of State (EoS), radial derivatives of energy density and anisotropic pressures, Tolman-Oppenheimer-Volkoff equilibrium condition, relativistic adiabatic index, sound speed, and surface redshift. Most of the aforementioned conditions are satisfied. Therefore, the solutions derived in the current study lie in the physically acceptable regime.
Deep inelastic scattering with proton target in the presence of gluon condensation using holography
Sara Tahery, Xiaopeng Wang, Xurong Chen
Published: , doi: 10.1088/1674-1137/ac936b
We study the deep inelastic scattering (DIS) of a proton-targeted lepton in the presence of gluon condensation using gauge/gravity duality. We use a modified ${\rm AdS}_5$ background where the modification parameter c corresponds to the gluon condensation in the boundary theory. First, by examining the electromagnetic field, we establish that a non-zero c can increase field magnitude. Our aim is to obtain the acceptable value of c for this scattering. Our method is based on setting the mass of the proton as an eigenvalue of the baryonic state equations of the DIS to find the acceptable value of the parameter c on the other side of the equations. Therefore, in the second step, we calculate wave function equations for the baryonic states where the mass of the proton target requires a value contribution of c as $ c=0.0120 \; \rm GeV^4 $. Proceeding with the electromagnetic field and baryonic states, we derive the holographic interaction action related to the amplitude of the scattering. Finally, we compute the corresponding structure functions numerically as functions of x and q, which are Björken variables and the lepton momentum transfers, respectively. Comparing the Jlab Hall C data with our theoretical calculations, our results are acceptable.
Deep learning method for testing the cosmic distance duality relation
Li Tang, Hai-Nan Lin, Liang Liu
Published: , doi: 10.1088/1674-1137/ac945b
The cosmic distance duality relation (DDR) is constrained by a combination of type-Ia supernovae (SNe Ia) and strong gravitational lensing (SGL) systems using the deep learning method. To make use of the full SGL data, we reconstruct the luminosity distance from SNe Ia up to the highest redshift of SGL using deep learning, and then, this luminosity distance is compared with the angular diameter distance obtained from SGL. Considering the influence of the lens mass profile, we constrain the possible violation of the DDR in three lens mass models. The results show that, in the singular isothermal sphere and extended power-law models, the DDR is violated at a high confidence level, with the violation parameter $ \eta_0=-0.193^{+0.021}_{-0.019} $ and $ \eta_0=-0.247^{+0.014}_{-0.013} $, respectively. In the power-law model, however, the DDR is verified within a 1σ confidence level, with the violation parameter $ \eta_0=-0.014^{+0.053}_{-0.045} $. Our results demonstrate that the constraints on the DDR strongly depend on the lens mass models. Given a specific lens mass model, the DDR can be constrained at a precision of $O(10^{-2}) $ using deep learning.
Weak gravity conjecture from conformal field theory: a challenge from hyperscaling violating and Kerr-Newman-AdS black holes
Jafar Sadeghi, Mehdi Shokri, Mohammad Reza Alipour, Saeed Noori Gashti
Published: , doi: 10.1088/1674-1137/ac957b
We search for a possible relationship between weak gravity conjecture (WGC) and conformal field theory (CFT) in hyperscaling violating and Kerr-Newman-AdS black holes. We deal with the critical points of the black hole systems using the correlation function introduced in CFT and discuss WGC conditions using the imaginary part of the energy obtained from the critical points and their poles. Under the assumptions $ z=1 $, $ d=1 $, and $ \theta\rightarrow0^{-} $, we link WGC to hyperscaling violating black holes owing to the existence of $ r_{H} $ values larger and smaller than one. For the second black hole system, we study the conditions of WGC for Kerr-Newman-AdS black holes using rotation and radius parameters. Then, we show that the conditions of WGC are satisfied when the charged particle near the hyperscaling violating and Kerr-Newman black holes is $ \frac{1}{a} $ with a ratio $ \frac{a}{\ell}\ll 1 $.
Flux variations of cosmic ray air showers detected by LHAASO-KM2A during a thunderstorm on June 10, 2021
F. Aharonian, Q. An, Axikegu, L.X. Bai, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, J.T. Cai, Zhe Cao, Zhen Cao, J. Chang, J.F. Chang, E.S. Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X. J. Chen, Y. Chen, H.L. Cheng, N. Cheng, Y.D. Cheng, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, Z.G. Dai, Danzengluobu, D. della Volpe, K.K. Duan, J.H. Fan, Y.Z. Fan, Z.X. Fan, J. Fang, K. Fang, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Feng, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Gao, M.M. Ge, L.S. Geng, G.H. Gong, Q.B. Gou, M.H. Gu, F.L. Guo, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Guo, Y.A. Han, H.H. He, H.N. He, S.L. He, X.B. He, Y. He, M. Heller, Y.K. Hor, C. Hou, X. Hou, H.B. Hu, Q. Hu, S. Hu, S.C. Hu, X.J. Hu, D.H. Huang, W.H. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Huang, X.L. Ji, H.Y. Jia, K. Jia, K. Jiang, Z.J. Jiang, M. Jin, M.M. Kang, T. Ke, D. Kuleshov, B.B. Li, Cheng Li, Cong Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li,
Published: , doi: 10.1088/1674-1137/ac9371
The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA, and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during a thunderstorm on June 10, 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with a maximum fractional increase of 20%. The variations in trigger rates (increases or decreases) were found to be strongly dependent on the primary zenith angle. The flux of secondary particles increased significantly, following a trend similar to that of shower events. To better understand the observed behavior, Monte Carlo simulations were performed with CORSIKA and G4KM2A (a code based on GEANT4). We found that the experimental data (in saturated negative fields) were in good agreement with the simulations, assuming the presence of a uniform electric field of -700 V/cm with a thickness of 1500 m in the atmosphere above the observation level. Due to the acceleration/deceleration by the atmospheric electric field, the number of secondary particles with energy above the detector threshold was modified, resulting in the changes in shower detection rate.
Two-photon physics at future electron-positron colliders
I.R. Boyko, V.V. Bytev, A.S. Zhemchugov
Published: , doi: 10.1088/1674-1137/ac957c
Two photon collisions offer a variety of physics phenomena that can be studied at future electron-positron colliders. Using the planned CEPC parameters as a benchmark, we consider several topics within two-photon collisions. With the full integrated luminosity, Higgs boson photoproduction can be reliably observed, and large statistics on various quarkonium states can be collected. The LEP results for the photon structure function and tau lepton anomalous magnetic moment can be improved by 1-2 orders of magnitude.
Dependence of the tidal deformability of neutron stars on the nuclear equation of state
Wen-Jie Xie, Jian-Ling Chen, Zi-Wei Ma, Jun-Hua Guo, Long Zhu
Published: , doi: 10.1088/1674-1137/ac9888
Within the Bayesian framework, using an explicitly isospin-dependent parametric equation of state (EOS) for the core of neutron stars (NSs), we studied how the NS EOS behaves when we confront it with the tidal deformabilities $ \Lambda_{1.4} $ of canonical NSs with different error and different lower boundaries, and with the tidal deformabilities of massive NSs. We found that it does not significantly improve the constraints on the NS EOS but has a weak effect on narrowing down the slope parameter of the symmetry energy by decreasing the measurement errors of $ \Lambda_{1.4} $. Both the isospin-dependent and isospin-independent parts of the NS EOS were significantly constrained and raised as the tidal deformabilities of massive NSs were adopted in the calculations, especially in high-density regions. We also found that $ \Lambda_{1.4} $ is more competent to limit the curvature parameter than the slope parameter of the symmetry energy, whereas the opposite occurs for the radius of canonical NSs $ R_{1.4} $. The tidal deformability of an NS with two times the solar mass $ \Lambda_{2.0} $ is more sensitive to skewness than the curvature parameter of the symmetry energy, and $ \Lambda_{1.4} $ and $ R_{1.4} $ have no correlation with the former.
QCD sum rule study for hidden-strange pentaquarks
Pengfei Yang, Wei Chen
Published: , doi: 10.1088/1674-1137/ac9889
Inspired by the LHCb observations of hidden-charm $ P_{c(s)} $ states, we study their hidden-strange analog$ P_s $ states in both the $ [udu][\bar ss] $ and $ [uds][\bar su] $ configurations. We investigate $ P_s $ pentaquark states in the $ p\eta^\prime $, $ p\phi $, $ \Lambda K $, $ \Sigma K $, and $ \Sigma^\ast K^\ast $ structures with $J^P ={1}/{2}^-$ and $ \Sigma ^\ast K $ and $ \Sigma K^\ast $ with $J^P = {3}/{2}^-$ and calculate their masses in the framework of QCD sum rules. Our numerical results show that the extracted hadron masses for all the $ p\eta^\prime $, $ p\phi $, $ \Lambda K $, $ \Sigma K $, and $ \Sigma^\ast K^\ast $ structures are significantly higher than the $ \Sigma K $ mass threshold, and the masses for $ \Sigma ^\ast K $ and $ \Sigma K^\ast $are also higher than the threshold of the corresponding hadron; hence, no bound state exists in such channels, which is consistent with the current experimental status.
Analysis of the interaction between the ϕ meson and nucleus
Xiao-Yun Wang, Chen Dong, Quanjin Wang
Published: , doi: 10.1088/1674-1137/ac9a36
In this study, we systematically investigate the ϕ meson and nucleus interaction by analyzing and fitting the cross sections of $ \gamma N $$ \rightarrow \phi $N reactions near the threshold, where N represents the nucleus. Using the vector meson dominant model, the distribution of the ϕ-N scattering length is presented as a function of energy, and the results show that there is a slight increase in scattering length with increasing energy. Based on this, the average scattering length of a ϕ-proton is obtained as$ 0.10\pm0.01 $ fm by combining experimental data and theoretical models. Moreover, the average scattering length of the ϕ-deuteron interaction is derived to be $ 0.014\pm0.002 $ fm for the first time. Furthermore, the effect of the momentum transfer $|t_{{\rm min}}|$ on the ϕ-N scattering length at the threshold is discussed. The obtained results not only provide important theoretical information for a more comprehensive and accurate study of the ϕ-N scattering length, but also a basis for future experimental measurements of ϕ meson production.
Pattern for flavor-dependent quark-antiquark interaction
Muyang Chen, Lei Chang
A flavor-dependent kernel is constructed based on the rainbow-ladder truncation of the Dyson-Schwinger and Bethe-Salpeter equation approach of quantum chromodynamics. The quark-antiquark interaction is composed of a flavor-dependent infrared part and a flavor-independent ultraviolet part. Our model gives a successful and unified description of the light, heavy, and heavy-light ground pseudoscalar and vector mesons. For the first time, our model shows that the infrared-enhanced quark-antiquark interaction is stronger and wider for lighter quarks.