Higlights
• Exploring the entanglement of free spin-${\bf\dfrac{1}{2}}$, spin-1 and spin-2 fields
2019, 43(5): 053102. doi: 10.1088/1674-1137/43/5/053102
In this study, we explore the entanglement of free spin-$\displaystyle\frac{1}{2}$, spin-1, and spin-2 fields. We start with an example involving Majorana fields in 1+1 and 2+1 dimensions. Subsequently, we perform the Bogoliubov transformation and express the vacuum state with a particle pair state in the configuration space, which is used to calculate the entropy. This clearly demonstrates that the entanglement entropy originates from the particles across the boundary. Finally, we generalize this method to free spin-1 and spin-2 fields. These higher free massless spin fields have well-known complications owing to gauge redundancy. We deal with the redundancy by gauge-fixing in the light-cone gauge. We show that this gauge provides a natural tensor product structure in the Hilbert space, while surrendering explicit Lorentz invariance. We also use the Bogoliubov transformation to calculate the entropy. The area law emerges naturally by this method.
• Monopole effects, core excitations, and ${\beta}$ decay in the A = 130 hole nuclei near 132Sn
2019, 43(5): 054101. doi: 10.1088/1674-1137/43/5/054101
The proton and neutron cross-shell excitations across the Z = 50 shell are investigated in the southwest quadrant of 132Sn by large-scale shell-model calculations with extended pairing and multipole-multipole force. The model space allows proton (neutron) core excitations, and both the low- and high-energy states for 130In are well described, as found by comparison with the experimental data. The monopole effects between the proton orbit $g_{9/2}$ and neutron orbit $g_{7/2}$ are studied as the new monopole correction that perfectly reproduces the first 1+ level in 130In. The energy interval of proton (neutron) core excitations in 130In lies in the range of 4.5−6.5 (2.0−4.1) MeV, and the high energy yrast states are predicted as neutron core excitations. The $\beta$ decays are calculated among the A=130 nuclei of 130In, 130Sn and 130Cd.
• Long live the Higgs factory: Higgs decays to long-lived particles at future lepton colliders
2019, 43(5): 053101. doi: 10.1088/1674-1137/43/5/053101
We initiate the study of exotic Higgs decays to long-lived particles (LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.
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• Time-crystal ground state and production of gravitational waves from QCD phase transition
Published: 2019-04-19, doi: 10.1088/1674-1137/43/6/065101
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We propose a novel mechanism for the production of gravitational waves in the early Universe that originates from the relaxation processes induced by the QCD phase transition. While the energy density of the quark-gluon mean-field is monotonously decaying in real time, its pressure undergoes a series of violent oscillations at the characteristic QCD time scales that generate a primordial multi-peaked gravitational waves signal in the radio frequencies’ domain. The signal is an echo of the QCD phase transition that is accessible by planned measurements at the FAST and SKA telescopes.
• Structure, formation, and decay of ${{\bar{K}NN}}$ system by Faddeev-AGS calculations
Published: 2019-04-15, doi: 10.1088/1674-1137/43/6/064101
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The Faddeev AGS equations for the coupled-channels $\bar{K}NN-\pi\Sigma{N}$ system with quantum numbers I = 1/2 and S = 0 are solved. Using separable potentials for the $\bar{K}N-\pi\Sigma$ interaction, we calculate the transition probability for the $(Y_{K})_{I=0}+N\rightarrow\pi\Sigma{N}$ reaction. The possibility to observe the trace of the $K^{-}pp$ quasi-bound state in $\pi\Sigma{N}$ mass spectra was studied. Various types of chiral-based and phenomenological potentials are used to describe the $\bar{K}N-\pi\Sigma$ interaction. Finally, we show that we can observe the signature of the $K^{-}pp$ quasi-bound state in the mass spectra, as well as the trace of branch points in the observables.
• Triple α -particle resonances in the decay of hot nuclear systems
Published: 2019-04-08, doi: 10.1088/1674-1137/43/6/064102
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The Efimov (Thomas) trimers in excited 12C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64Ni) + 70(64)Zn(64Ni) reactions at the beam energy of E/A = 35 MeV/nucleon. In heavy ion collisions, $\alpha$-particles interact with each other and can form complex systems such as 8Be and 12C. For the 3 $\alpha$-particle systems, multi-resonance processes give rise to excited levels of 12C. The interaction between any two of the 3 $\alpha$-particles provides events with one, two or three 8Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events with the three $\alpha$-particle relative energies consistent with the ground state of 8Be are observed with the decrease of the instrumental error for the reconstructed 7.458 MeV excitation level in 12C, which was suggested as the Efimov (Thomas) state.
Current Issued
2019 Vol. 43, No. 5
Published: 18 April 2019
Archive
IF: 3.298

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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