Highlights
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Holographic timelike entanglement entropy from Rindler method
2024, 48(11): 115113. doi: 10.1088/1674-1137/ad57a8
For a Lorentzian invariant theory, the entanglement entropy should be a function of the domain of dependence of the subregion under consideration. More precisely, it should be a function of the domain of dependence and the appropriate cut-off. In this study, we refine the concept of cut-off to make it applicable to timelike regions and assume that the usual entanglement entropy formula also applies to timelike intervals. Using the Rindler method, the timelike entanglement entropy can be regarded as the thermal entropy of the CFT after the Rindler transformation plus a constant${\rm i}\pi c/6$ , where c denotes the central charge. The gravitational dual of the 'covariant' timelike entanglement entropy is presented following this method. -
Form factor for Dalitz decays from J/ψ to light pseudoscalars
2024, 48(11): 113105. doi: 10.1088/1674-1137/ad641b
We calculate the form factor$M(q^2)$ for the Dalitz decay$J/\psi\to \gamma^*(q^2)\eta_{(N_f=1)}$ with$\eta_{(N_f)}$ being the SU($N_f$ ) flavor singlet pseudoscalar meson. The difference among the partial widths$\Gamma(J/\psi\to \gamma \eta_{(N_f)})$ at different$N_f$ can be attributed in part to the$N_f$ and quark mass dependences induced by the$\mathbf{U}_A(1)$ anomaly dominance.$M(q^2)$ in both$N_f=1,2$ is well described by the single pole model$M(q^2)=M(0)/(1-q^2/\Lambda^2)$ . Combined with the known experimental results of the Dalitz decays$J/\psi\to Pe^+e^-$ , the pseudoscalar mass$m_P$ dependence of the pole parameter$\Lambda$ is approximated by$\Lambda(m_P^2)=\Lambda_1(1-m_P^2/\Lambda_2^2)$ with$\Lambda_1={2.65(5)}~\mathrm{GeV}$ and$\Lambda_2={2.90(35)}~\mathrm{GeV}$ . These results provide inputs for future theoretical and experimental studies on the Dalitz decays$J/\psi\to Pe^+e^-$ . -
A new perspective on the diffuse gamma-ray emission excess
2024, 48(11): 115105. doi: 10.1088/1674-1137/ad72d4
The Large High-Altitude Air Shower Observatory (LHAASO) recently published measurements of diffuse Galactic gamma-ray emission (DGE) in the 10−1000 TeV energy range. The measured DGE flux is significantly higher than the expectation from hadronic interactions between cosmic rays (CRs) and the interstellar medium. This excess has been proposed to originate from unknown extended sources produced by electron radiation, such as pulsar wind nebulae or pulsar halos (PWNe/halos). In this paper, we propose a new perspective to explain the DGE excess observed by LHAASO. The masking regions used in the LHAASO DGE measurement may not fully encompass the extended signals of$\textit{known} $ PWNe/halos. By employing a two-zone diffusion model for electrons around pulsars, we find that the DGE excess in most regions of the Galactic plane can be well explained by the signal leakage model under certain parameters. Our results indicate that this signal leakage from known sources and contributions from unresolved sources should be considered as complementary in explaining the DGE excess.
Just Accepted
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Rotational properties and blocking effects in N = 152 isotones 254No, 255Lr, and 256Rf
Published: 2024-11-19
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Two-zero textures for Dirac Neutrinos
Published: 2024-11-19
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Constraining Symmetry Energy from Pygmy Dipole Resonances in 68Ni and 132Sn
Published: 2024-11-16
Recent
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Possibility of synthesizing Z = 119 superheavy nuclei with Z > 20 projectiles
2024, 48(12): 124105-124105-8. doi: 10.1088/1674-1137/ad86b0Show AbstractWe employ the dinuclear system (DNS) model combined with a statistical model to calculate the evaporation residue cross sections of the reaction systems
$ ^{48} $ Ca +$ ^{243} $ Am,$ ^{48} $ Ca +$ ^{248} $ Cm, and$ ^{48} $ Ca +$ ^{249} $ Bk. The theoretical results successfully reproduce the experimental trends in the 3n and 4n evaporation channels of these reaction systems. To synthesize the new element$ Z = 119 $ , we predict the evaporation residue cross sections for three reaction systems ($ ^{54} $ Cr +$ ^{243} $ Am,$ ^{51} $ V +$ ^{248} $ Cm, and$ ^{50} $ Ti +$ ^{249} $ Bk) to select the most promising projectile-target combinations. We also note that the maximum cross sections predicted by our model and other methods appear to be below the detection limits of current experimental facilities, given the projectile-target combinations feasible under current experimental conditions. Therefore, synthesizing superheavy nuclei with$ Z = 119 $ will require improvements in beam intensity, detection techniques, and effective separation methods. -
Comprehensive constraints on fermionic dark matter-quark tensor interactions in direct detection experiments
2024, 48(12): 123103-123103-13. doi: 10.1088/1674-1137/ad77b3Show AbstractEffective field theory (EFT) provides a model-independent framework for interpreting the results of dark matter (DM) direct detection experiments. In this study, we demonstrate that the two fermionic DM-quark tensor operators
$(\bar{\chi} {\rm{i}}\sigma^{\mu\nu} \gamma^5 \chi) (\bar{q} \sigma_{\mu\nu}q)$ and$ (\bar{\chi} \sigma^{\mu\nu} \chi) (\bar{q} \sigma_{\mu\nu} q) $ can contribute to the DM electric and magnetic dipole moments via nonperturbative QCD effects, in addition to the well-studied contact DM-nucleon operators. We then investigate the constraints on these two operators by considering both the contact and dipole contributions using the XENON1T nuclear recoil and Migdal effect data. We also recast other existing bounds on the DM dipole operators, derived from electron and nuclear recoil measurements in various direct detection experiments, as constraints on the two tensor operators. For$m_\chi \lesssim 1\;{\rm{GeV}}$ , our results significantly extend the reach of constraints on the DM-quark tensor operators to masses as low as$5\;{\rm{MeV}}$ , with the bound exceeding that obtained by the Migdal effect with only contact interactions by approximately an order of magnitude. In particular, for the operator$(\bar{\chi} \sigma^{\mu\nu}{\rm{i}}\gamma_5 \chi) (\bar{q} \sigma_{\mu\nu}q)$ with DM mass$m_\chi \gtrsim 10\;{\rm{GeV}}$ , the latest PandaX constraint on the DM electric dipole moment puts more stringent bounds than the previous direct detection limit. We also briefly discuss the constraints obtained from experiments other than direct detection. -
Rapid identification of time-frequency domain gravitational wave signals from binary black holes using deep learning
2024, 48(12): 125107-125107-13. doi: 10.1088/1674-1137/ad73acShow AbstractRecent developments in deep learning techniques have provided alternative and complementary approaches to the traditional matched-filtering methods for identifying gravitational wave (GW) signals. The rapid and accurate identification of GW signals is crucial to the advancement of GW physics and multi-messenger astronomy, particularly considering the upcoming fourth and fifth observing runs of LIGO-Virgo-KAGRA. In this study, we used the 2D U-Net algorithm to identify time-frequency domain GW signals from stellar-mass binary black hole (BBH) mergers. We simulated BBH mergers with component masses ranging from 7 to 50
$ M_{\odot}$ and accounted for the LIGO detector noise. We found that the GW events in the first and second observation runs could all be clearly and rapidly identified. For the third observing run, approximately 80% of the GW events could be identified. In contrast to traditional convolutional neural networks, the U-Net algorithm can output time-frequency domain signal images corresponding to probabilities, providing a more intuitive analysis. In conclusion, the U-Net algorithm can rapidly identify the time-frequency domain GW signals from BBH mergers.
Current Issued
2024 Vol. 48, No. 11
Published: 29 October 2024
Published: 29 October 2024
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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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Cover Story
- Cover Story (Issue 11, 2024) ｜ Form factor for Dalitz decays from J/ψ to light pseudoscalars
- Cover Story (Issue 3, 2024) | First measurement of the ground-state mass of 22Al helps to evaluate the ab-initio theory
- Cover Story (Issue 9, 2024) Measurement of solar pp neutrino flux using electron recoil data from PandaX-4T commissioning run
- Cover Story (Issue 2, 2024) | Quark/gluon taggers light the way to new physics
- Cover Story (Issue 8, 2024) | Applyingdeep learning technique to chiral magnetic wave search
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