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Published:   , doi: 10.1088/1674-1137/44/6/063105
Abstract:
In this paper, we construct the axialvector and tensor current operators to investigate the ground state tetraquark states and the first radially excited tetraquark states with the quantum numbers \begin{document}$J^{PC}=1^{+-}$\end{document} via the QCD sum rules systematically, and observe that there are one axialvector tetraquark candidate for the \begin{document}$Z_c(3900)$\end{document} and \begin{document}$Z_c(4430)$\end{document}, two axialvector tetraquark candidates for the \begin{document}$Z_c(4020)$\end{document}, three axialvector tetraquark candidates for the \begin{document}$Z_c(4600)$\end{document}.
Published:   , doi: 10.1088/1674-1137/44/6/063106
Abstract:
The \begin{document}$ZZ\gamma$\end{document} triple neutral gauge couplings are absent in the Standard Model (SM) at the tree level. They receive no contributions from dimension-6 effective operators, but can arise from effective operators of dimension-8. We study the scale of new physics associated with such dimension-8 operators that can be probed by measuring the reaction \begin{document}$\,e^+e^-\to Z\gamma$\end{document} followed by \begin{document}$\,Z\to\ell\bar\ell,\nu \bar \nu$\end{document} decays, at future \begin{document}$e^+e^-$\end{document} colliders including the CEPC, FCC-ee, ILC and CLIC. We demonstrate how angular distributions of the final-state mono-photon and leptons can play a key rôle in suppressing SM backgrounds. We further demonstrate that using electron/positron beam polarizations can significantly improve the signal sensitivities. We find that the dimension-8 new physics scale can be probed up to the multi-TeV region at such lepton colliders.
Published:   , doi: 10.1088/1674-1137/44/7/074101
Abstract:
Inspired by the recent experimental breakthrough in identifying the last bound neutron-rich nuclei in the fluorine and neon isotopes, we perform a theoretical study of the Z = 9, 10, 11, 12 isotopes in the relativistic mean field model. The mean field parameters are those of the PK1 parameterization while the pairing correlation is described by the particle number conservation BCS (FBCS) method recently formulated in the RMF model. We show that the FBCS approach plays an essential role in reproducing the experimental results of the fluorine and neon isotopes. In addition, we predict 39Na and 40Mg to be the last bound neutron-rich nuclei in the sodium and magnesium isotopes.
Published:   , doi: 10.1088/1674-1137/44/6/063102
Abstract:
Using the latest PandaX limits on light dark matter (DM) with light mediator, we check the implication on the parameter space of the general singlet extension of MSSM (without Z3 symmetry), which can have a sizable DM self-interaction to solve the small-scale structure problem. We find that the PandaX limits can stringently constrain such a paramter space, depending on the coupling λ between the singlet and doublet Higgs fields. For the singlet extension of MSSM with Z3 symmetry, the so-called NMSSM, we also demonstrate the PandaX constraints on its parameter space which gives a light DM with correct relic density but without sufficient self-interaction to solve the small-scale structure problem. We find that in this NMSSM the GeV dark matter with a sub-GeV mediator has been stringently constrained.
Published:   , doi: 10.1088/1674-1137/44/7/075101
Abstract:
We propose a new method to test the cosmic distance duality relation using the strongly lensed gravitational waves. The simultaneous observations of image positions, the relative time delay between different images, the redshift measurements of lens and source, together with the mass modelling of the lens galaxy, provide the angular diameter distance to the gravitational wave source. On the other hand, from the observation of gravitational wave signals the luminosity distance to the source can be obtained. This is to our knowledge the first method to simultaneously measure both the angular diameter distance and luminosity distance from the same source. Thus, the strongly lensed gravitational waves provide a unique way to test the cosmic distance duality relation. With the construction of the third generation gravitational detectors such as the Einstein Telescope in the future, it is possible to test the cosmic distance duality relation at an accuracy of several percent.
Published:   , doi: 10.1088/1674-1137/44/7/074001
Abstract:
The radionuclide \begin{document}$^{22}$\end{document}Na, which leads to the emission of a characteristic 1.275 MeV \begin{document}$\gamma$\end{document}-ray, is a potential astronomical observable that is expected to be produced in classical novae. The \begin{document}$^{22}{{\rm{Mg}}}(p,\,\gamma)^{23}{{\rm{Al}}}$\end{document} reaction is relevant to the nucleosynthesis of \begin{document}$^{22}$\end{document}Na in Ne-rich novae. In this work, the squared neutron asymptotic normalization coefficients (ANCs) for virtual decay of \begin{document}$^{23}{{\rm{Ne}}}$\end{document} \begin{document}$\to$\end{document} \begin{document}$^{22}{{\rm{Ne}}}$\end{document} + n were extracted to be \begin{document}$0.483\pm0.060$\end{document} fm\begin{document}$^{-1}$\end{document} and \begin{document}$9.7\pm2.3$\end{document} fm\begin{document}$^{-1}$\end{document} for the ground state and the first excited state from the experimental angular distributions of \begin{document}${}^{22}{{\rm{Ne}}}(d,\,p){}^{23}{{\rm{Ne}}}$\end{document} populating the ground state and the first excited state of \begin{document}$^{23}{{\rm{Ne}}}$\end{document} respectively, using the the adiabatic distorted wave approximation (ADWA) and continuum discretized coupled channel (CDCC) methods. Then the squared proton ANC of \begin{document}${}^{23}{{\rm{Al}}}_{\rm{g.s.}}$\end{document} was derived to be \begin{document}$C_{d5/2}^{2}({}^{23}{{\rm{Al}}})=(2.65\pm0.33)\times10^{3}$\end{document} fm\begin{document}$^{-1}$\end{document} according to charge symmetry of strong interaction. The astrophysical S-factors and reaction rates for the direct capture contribution in \begin{document}${}^{22}{{\rm{Mg}}}(p,\,\gamma){}^{23}{{\rm{Al}}}$\end{document} were also presented. In addition, the proton width of the first excited state of \begin{document}$^{23}{{\rm{Al}}}$\end{document} was derived to be \begin{document}$57\pm14$\end{document} eV from the neutron ANC of its mirror state in \begin{document}$^{23}{{\rm{Ne}}}$\end{document} and used to compute the contribution from the first resonance of \begin{document}$^{23}{{\rm{Al}}}$\end{document}. Our result demonstrates that the direct capture dominates the \begin{document}$^{22}{{\rm{Mg}}}(p,\,\gamma)^{23}{{\rm{Al}}}$\end{document} reaction at most of the temperatures of astrophysical relevance but between \begin{document}$0.33 < T_9<0.64$\end{document}.
Published:   , doi: 10.1088/1674-1137/44/6/064104
Abstract:
Starting from deformed AdS5 spaces due to the presence of modified warp factors in their metric tensors, we use the AdS/CFT correspondence within this approach to calculate the spectra for even and odd glueballs, scalar and vector mesons, and baryons with different spins. For the glueball cases we derive their Regge trajectories and compare with the ones related to the pomeron and the odderon. In the case of the scalar and vector mesons and baryons the masses found here are compatible with the PDG. In particular for these hadrons we found Regge trajectories compatible with another holographic approach and also with the hadronic spectroscopy which present an universal Regge slope around 1.1 GeV2.
Published:   , doi: 10.1088/1674-1137/44/6/065105
Abstract:
In this paper, we have discussed the \begin{document}$P-V$\end{document} criticality and Joule-Thomson expansion of charged AdS black hole in the Rastall gravity. We first find for charged AdS black hole in the Rastall gravity, although the equation of state is related to the Rastall parameter \begin{document}$\lambda$\end{document}, its reduced equation of state at the critical scales is independent of the Rastall parameter \begin{document}$\lambda$\end{document}, as that is for the Einstein gravity where \begin{document}$\lambda=0$\end{document}. This is the reason why the critical exponents are not related to the Rastall parameter \begin{document}$\lambda$\end{document}. On the other hand, for charged AdS black hole in the Rastall gravity, the inversion temperature \begin{document}${T_{i}}$\end{document} is related to the Rastall parameter \begin{document}$\lambda$\end{document}, but the minimum inversion temperature \begin{document}${T_{i}}^{min}$\end{document} and the ratio \begin{document}$\varepsilon$\end{document} between the minimum inversion temperature and the critical temperature are both independent of the Rastall parameter \begin{document}$\lambda$\end{document}. To conclude, at the critical point, the thermodynamic evolutions of charged AdS black hole in the Rastall gravity behave as those of the van der Waals fluids and charged AdS black holes in the Einstein gravity. Moreover, we plot the inversion curves and isenthalpic curves in \begin{document}$T-P$\end{document} plane and analyze the effects of the Rastall constant \begin{document}$\lambda$\end{document} on the inversion curves of charged AdS black holes during the Joule-Thomson expansion.
Published:   , doi: 10.1088/1674-1137/44/6/065002
Abstract:
Precise measurement about the cosmic-ray (CR) knees of different primaries is essential for revealing the mistery of CR's acceleration and propagation mechanism, as well as exploring new physics. However, classification about the CR components is a tough task especially for the groups with the atomic number close to each other. Realizing that deep learning has achieved a remarkable breakthrough in many fields, we seek for leveraging this technology to improve the classification performance of the CR Proton and Light groups of the LHAASO-KM2A experiment. In this work, we propose a fused Graph Neural Network model for the KM2A arrays, in which the activated detectors are structured into graphs. We find that the signal and background can be effectively discriminated in this model, and its performance outperforms both the traditional physics-based method and the Convolutional Neural Network (CNN)-based model across the whole energy range.
Published:   , doi: 10.1088/1674-1137/44/6/065106
Abstract:
In this paper, we study the matter accretion onto Einstein-Aether black holes by adopting the Hamiltonian approach. We discuss the general solution of accretion using isothermal equation of state. Particularly, we consider different types of fluids such as ultra-relativistic fluid, ultra-stiff fluid, sub-relativistic fluid, radiation fluid and analyzed its accretion process onto Einstein-Aether black holes. The behavior of fluid flow and existence of critical points is being checked for Einstein-Aether black holes. We also discuss the general expression and behavior of polytropic fluid onto Einstein-Aether black holes. The most important feature of this work is to investigate the mass accretion rate of above mentioned fluids and compare our finding with Schwarzschild black hole which produce particular signatures. Moreover, the maximum mass accretion rate occur near the Killing and universal horizons and minimum accretion rate lies in between it.
Published:   , doi: 10.1088/1674-1137/44/6/063104
Abstract:
In this paper, we revisit the heavy quarkonium leptonic decays \begin{document}$\psi(nS) \to \ell^+\ell^-$\end{document} and \begin{document}$\Upsilon(nS) \to \ell^+\ell^-$\end{document} using the Bethe-Salpeter method. The emphasis is paid to the relativistic correction. For the cases of \begin{document}$\psi(1S-5S)$\end{document} decay, the relativistic effects are \begin{document}$22^{+3}_{-2}$\end{document}%, \begin{document}$34^{+5}_{-5}$\end{document}%, \begin{document}$41^{+6}_{-6}$\end{document}%, \begin{document}$52^{+11}_{-13}$\end{document}% and \begin{document}$62^{+14}_{-12}$\end{document}%, respectively. And for the cases of \begin{document}$\Upsilon(1S-5S)$\end{document} decay, the relativistic effects are \begin{document}$14^{+1}_{-2}$\end{document}%, \begin{document}$23^{+0}_{-3}$\end{document}%, \begin{document}$20^{+8}_{-2}$\end{document}%, \begin{document}$21^{+6}_{-7}$\end{document}% and \begin{document}$28^{+2}_{-7}$\end{document}%, respectively. Thus the relativistic corrections are large and important for heavy quarkonium leptonic decays, especially for the highly excited charmoniums. Our results of \begin{document}$\Upsilon(nS) \to \ell^+\ell^-$\end{document} consist well with experimental data.
Published:   , doi: 10.1088/1674-1137/44/6/064102
Abstract:
Exact solution of the U(5)-O(6) transitional description in the interacting boson model with two-particle and two-hole configuration mixing is derived based on the Bethe ansatz approach. The Bethe ansatz equations in determining eigenstates and the corresponding eigen-energies of the model are provided. Specific N=2 and N=4 cases are exemplified to demonstrate the feature of the solution. As an example of the application, some low-lying level energies and B(E2) ratios of 108Cd are fitted and compared with the corresponding experimental data.
Published:   , doi: 10.1088/1674-1137/44/6/061001
Abstract:
In the semi-constrained NMSSM (scNMSSM, or NMSSM with non-universal Higgs mass) under current constraints, we consider a scenario where \begin{document}$h_2$\end{document} is the SM-like Higgs, \begin{document}$\tilde{\chi}^0_1$\end{document} is singlino-dominated LSP, \begin{document}$\tilde{\chi}^{\pm}_1$\end{document} and \begin{document}$\tilde{\chi}^0_{2,3}$\end{document} are mass-degenerated, light and higgsino-dominated NLSPs (next-to-lightest supersymmetric particles). We investigate the constraints to these NLSPs from searching for SUSY particles at the LHC Run-I and Run-II, discuss the possibility of discovering these NLSPs in the future, and come to the following conclusions: (i) With all data of Run I and up to \begin{document}$36\;{\rm{fb}}^{-1}$\end{document} data of Run II at the LHC, the search results by ATLAS and CMS can still not exclude the higgsino-dominated NLSPs of \begin{document}$100\sim200\;{\rm{GeV}}$\end{document}. (ii) When the mass difference with \begin{document}$\tilde{\chi}^0_{1}$\end{document} is smaller than \begin{document}$m_{h_2}$\end{document}, \begin{document}$\tilde{\chi}^0_{2}$\end{document} and \begin{document}$\tilde{\chi}^0_{3}$\end{document} have opposite preference on decaying to \begin{document}$Z/Z^*$\end{document} or \begin{document}$h_1$\end{document}. (iii) When the mass difference between NLSP and LSP is larger than \begin{document}$m_Z$\end{document}, most of the samples can be checked at \begin{document}$5\sigma$\end{document} level with future \begin{document}$300\;{\rm{fb}}^{-1}$\end{document} data at the LHC. While with \begin{document}$3000\;{\rm{fb}}^{-1}$\end{document} data at the High Luminosity LHC (HL-LHC), nearly all of the samples can be checked at \begin{document}$5\sigma$\end{document} level even if the mass difference is insufficient. (iv) The \begin{document}$a_1$\end{document} funnel and the \begin{document}$h_2/Z$\end{document} funnel mechanisms for the singlino-dominated LSP annihilating can not be distinguished by searching for NLSPs.
Published:   , doi: 10.1088/1674-1137/44/6/063103
Abstract:
A number of predictions were made in Ref. [1] pertaining to the anomalous production of multiple leptons at the Large Hadron Collider (LHC). Discrepancies in multi-lepton final states have now become statistically compelling with the available Run 2 data. These could be connected with a heavy boson, H, decaying predominantly into a SM Higgs boson, h, and a singlet scalar, S, where \begin{document}$m_H\approx 270$\end{document} GeV and \begin{document}$m_S\approx 150$\end{document} GeV. These can be embedded into a scenario where a Two Higgs Doublet is considered with an additional singlet scalar, 2HDM+S. The long-standing discrepancy in the muon anomalous magnetic moment, \begin{document}$\Delta a_\mu$\end{document}, is interpreted in the context of the 2HDM+S type-II and type-X, along with additional fermionic degrees of freedom. The 2HDM+S model alone with the constraints from the LHC data does not seem to explain the \begin{document}$\Delta a_\mu$\end{document} anomaly. However, adding fermions with mass of order \begin{document}${\cal O}(100)$\end{document} GeV can explain the discrepancy for low enough values of fermion-scalar couplings.
Published:   , doi: 10.1088/1674-1137/44/6/065103
Abstract:
We propose a cosmological scenario which describes the evolution history of the universe based on the particle creation and holographic equipartition. The model attempts to solve the inflation of the early universe and the accelerated expansion of the present universe without introducing the dark energy from the perspective of thermodynamics. Throughout the evolution of the universe, we assume that the universe always creates particles in some way and holographic equipartition is always satisfied. Further, we choose that the creation rate of particles is proportional to \begin{document}$H^{2}$\end{document} in the early universe and to H in the present and late universe, where H is the Hubble parameter. Then we obtain the solutions \begin{document}$a(t)\propto e^{\alpha t/3}$\end{document} and \begin{document}$a(t)\propto t^{1/2}$\end{document} for the early universe and the solutions \begin{document}$a(t)\propto t^{\delta}$\end{document} and \begin{document}$a(t)\propto e^{Ht}$\end{document} for the present and late universe, where \begin{document}$\alpha$\end{document} and \begin{document}$\delta$\end{document} are the parameters. Finally, we obtain and analyze two important thermodynamic properties for the present model.
Published:   , doi: 10.1088/1674-1137/44/5/053102
Abstract:
In this paper, we studied the semileptonic \begin{document}$B/B_s \to (D^{(*)},D_s^{(*)}) l\nu_l$\end{document} decays in the framework of the standard model (SM), by employing the perturbative QCD (PQCD) factorization formalism combining with the lattice QCD inputs of the relevant transition form factors. We calculated the branching ratios \begin{document}${\cal B}(B_{(s)} \to D_{(s)}^{(*)} l \nu_l )$\end{document} with \begin{document}$l = (e,\mu,\tau)$\end{document}, the ratios of the branching ratios \begin{document}$R(D^{(*)})$\end{document} and \begin{document}$R(D_s^{(*)} )$\end{document} and other physical observables \begin{document}$P_\tau(D_{(s)}^{(*)})$\end{document}, \begin{document}$F_L(D^*_{(s)})$\end{document} and \begin{document}$A_{FB}(\tau)$\end{document}. The “PQCD+Lattice” predictions for \begin{document}${\cal B}(B \to D^{(*)} l\nu_l)$\end{document} and \begin{document}$R(D^{(*)})$\end{document} do agree well with those currently available experimental measurements within the errors. For the ratios \begin{document}$R(D_s)$\end{document} and \begin{document}$R(D_s^*)$\end{document}, the "PQCD+Lattice" predictions agree well with other known predictions. For both \begin{document}$P_\tau(D^*)$\end{document} and \begin{document}$F_L(D^*)$\end{document}, our theoretical predictions agree well with the measured values within errors. Our theoretical predictions about the considered semileptonic \begin{document}$B/B_s$\end{document} decays could be tested in the near future LHCb and the Belle II experiments.
Published:   , doi: 10.1088/1674-1137/44/6/065104
Abstract:
We study the collision property of spinning particles near a Bañados-Teitelboim-Zanelli (BTZ) black hole. Our results show that although the center-of-mass energy of two ingoing particles diverges if one of the particles possesses a critical angular momentum, however, particle with critical angular momentum can not exist outside of the horizon due to the violation of timelike constraint. Further detailed investigation indicates that only a particle with a subcritical angular momentum is allowed to exist near an extremal rotating BTZ black hole and the corresponding collision center-of-mass energy can be arbitrarily large in a critical angular momentum limit.
Published:   , doi: 10.1088/1674-1137/44/5/053103
Abstract:
This paper extends the study of the quantum dissipative effects of a cosmological scalar field by taking into account the cosmic expansion and contraction. Cheung, Drewes, Kang and Kim [1] calculated the effective action and quantum dissipative effects of a cosmological scalar field. The analytic expressions for the effective potential and damping coefficient were presented using a simple scalar model with quartic interaction. Their work was done using Minkowski-space propagators in loop diagrams. In this work we incorporate the Hubble expansion and contraction of the cosmic background, and focus on the thermal dynamics of a scalar field in a regime where the effective potential changes slowly. We let the Hubble parameter, H, attain a small but non-zero value and carry out calculations to first order in H. If we set H = 0, all results match those [1] in flat spacetime. Interestingly we have to integrate over the resonances, which in turn leads to an amplification of the effects of a non-zero H. This is an intriguing phenomenon which cannot be uncovered in flat spacetime. The implications on particle creations in the early universe will be studied in a forthcoming work.
Published:   , doi: 10.1088/1674-1137/44/6/065001
Abstract:
The Water Cherenkov Detector Array (WCDA) is a major component of the Large High Altitude Air Shower Array Observatory (LHAASO), a new generation cosmic-ray experiment with unprecedented sensitivity, currently under construction. The WCDA is aimed at the study of TeV \begin{document}$\gamma$\end{document}-rays. In order to evaluate the prospects of searching for TeV \begin{document}$\gamma$\end{document}-ray sources with the WCDA, we present in this paper a projection for the one-year sensitivity of the WCDA to TeV \begin{document}$\gamma$\end{document}-ray sources from TeVCat1) using an all-sky approach. Out of 128 TeVCat sources observable to the WCDA up to a zenith angle of \begin{document}$45^\circ$\end{document}, we estimate that 42 would be detectable for one year of observations at a median energy of 1 TeV. Most of them are Galactic sources, and the extragalactic sources are Active Galactic Nuclei (AGN).
Published:   , doi: 10.1088/1674-1137/44/6/065102
Abstract:
Asymptotically safe gravity is one effective approach to quantum gravity. It is important to differentiate the modified gravity inspired by asymptotically safe gravity. In this paper, we examine the matter particles dynamics near the improved version of Schwarzschild black hole. We assume that in the context of asymptotically safe gravity scenario the ambient matter surrounding the black hole is of isothermal in nature and investigate the spherical accretion of matter by deriving solutions at critical points. The analysis for the various values of the state parameter for isothermal test fluids, viz., k = 1, 1/2, 1/3, 1/4 show the possibility of accretion onto asymptotically safe black hole. We formulate the accretion problem as Hamiltonian dynamical system and explain its phase flow in detail which reveals interesting results in asymptotically safe gravity theory.
Published:   , doi: 10.1088/1674-1137/44/5/054105
Abstract:
Using several source models, we analyze the transverse momentum dependence of HBT radii in the relativistic heavy-ion collisions. The results indicate that the single-particle space-momentum angle distribution plays an important role in the transverse momentum dependence of HBT radii. In a cylinder source, we use several formulas to describe the transverse momentum dependence of HBT radii and the single-particle space-momentum angle distribution. We also make a numerical connection between them in the transverse plane.
Published:   , doi: 10.1088/1674-1137/44/5/055103
Abstract:
The first law of black hole thermodynamics in the extended phase space is prevailing recently. However, the second law as well as the weak cosmic censorship conjecture has not been investigated extensively. In this paper, we investigate the laws of thermodynamics and the weak cosmic censorship conjecture of an AdS black hole with a global monopole in the extended phase space under a charged particle absorption. It is shown that the first law of thermodynamics is valid, while the second law is violated for the extremal and near-extremal black holes. Moreover, for the weak cosmic censorship conjecture, we find it is valid only for the extremal black holes, and it is violable for the near-extremal black hole, which is different from the previous results.
Published:   , doi: 10.1088/1674-1137/44/5/055101
Abstract:
We construct an alternative uniformly accelerated reference frame based on 3+1 formalism in adapted coordinate. It is distinguished with Rindler coordinate that there is time-dependent redshift drift between co-moving observers. The experimentally falsifiable distinguishment might promote our understanding of non-inertial frame in laboratory.
IF: 5.861

Monthly founded in 1977

ISSN 1674-1137 CN 11-5641/O4

Original research articles, Ietters and reviews Covering theory and experiments in the fieids of

• Particle physics
• Nuclear physics
• Particle and nuclear astrophysics
• Cosmology
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