Using the vector exchange interaction in the local hidden gauge approach, which in the light quark sector generates the chiral Lagrangians and has produced realistic results for
We study the spin precession frequency of a test gyroscope attached to a stationary observer in the five-dimensional rotating Kaluza-Klein black hole (RKKBH). We derive the conditions under which the test gyroscope moves along a timelike trajectory in this geometry, and the regions where the spin precession frequency diverges. The magnitude of the gyroscope precession frequency around the KK black hole diverges at two spatial locations outside the event horizon. However, in the static case, the behavior of the Lense-Thirring frequency of a gyroscope around the KK black hole is similar to the ordinary Schwarzschild black hole. Since a rotating Kaluza-Klein black hole is a generalization of the Kerr-Newman black hole, we present two mass-independent schemes to distinguish these two spacetimes.
Using all experimentally measured charmless
A microscopic approach is employed to study the optical potential for the 7Li-nucleus interaction system without any free parameters. It is obtained by folding the microscopic optical potentials of the constituent nucleons of 7Li over their density distributions. We employ an isospin-dependent nucleon microscopic optical potential, which is based on the Skyrme nucleon-nucleon effective interaction and derived using the Green's function method, as the nucleon optical potential. The harmonic oscillator shell model is used to describe the internal wave function of 7Li and obtain the nucleon density distribution. The 7Li microscopic optical potential is used to predict the reaction cross-sections and elastic scattering angular distributions for the target range from 27Al to 208Pb and energy range below 450 MeV. Generally, the results can reproduce the measured data reasonably well. In addition, the microscopic optical potential is comparable to a global phenomenological optical potential by fitting the presently existing measured data.
The sea quark contributions to the nucleon electromagnetic form factors of the up, down and strange quarks are studied with the nonlocal chiral effective Lagrangian. Both octet and decuplet intermediate states are included in the one loop calculations. Compared with the strange quark form factors, although their signs are the same, the absolute value of the light quark form factors are much larger. For both the electric and magnetic form factors, the contribution of the d quark is larger than of the u quark. The current lattice simulations of the light sea quark form factors are in between our results for the u and d quarks.
We used the cluster structure properties of the 212Po to estimate the neutron skin thickness of 208Pb. For this purpose, we considered two important components: (a) alpha decay is a low energy phenomenon; therefore, one can expect that the mean-field, which can explain the ground state properties of 212Po, does not change during the alpha decay process. (b) 212Po has a high alpha cluster-like structure, two protons and two neutrons outside its core nucleus with a double magic closed-shell, and the cluster model is a powerful formalism for the estimation of alpha decay preformation factor of such nuclei. The slope of the symmetry energy of 208Pb is estimated to be
The quantum electrodynamics (QED) in a spatially flat (1+3)-dimensional Friedmann-Lemaître-Robertson-Walker (FLRW) space-time with a Milne-type scale factor is outlined focusing on the amplitudes of the allowed processes in the first order perturbations. The definition of the transition rates is reconsidered such that an appropriate angular behavior of the probability for creation of an electron-positron pair from a photon is obtained, which has a similar rate as the creation of a photon and an electron-positron pair from vacuum. It is shown that these processes are allowed only in the first order perturbations, since the photon emission or absorption by an electron or positron are forbidden.
The energy per particle BA in nuclear matter is calculated up to high baryon density in the whole isospin asymmetry range from symmetric matter to pure neutron matter. The results, obtained in the framework of the Brueckner-Hartree-Fock approximation with two- and three-body forces, confirm the well-known parabolic dependence on the asymmetry parameter β = (N − Z)/A (β2 law) that is valid in a wide density range. To investigate the extent to which this behavior can be traced back to the properties of the underlying interaction, aside from the mean field approximation, the spin-isospin decomposition of BA is performed. Theoretical indications suggest that the β2 law could be violated at higher densities as a consequence of the three-body forces. This raises the problem that the symmetry energy, calculated according to the β2 law as a difference between BA in pure neutron matter and symmetric nuclear matter, cannot be applied to neutron stars. One should return to the proper definition of the nuclear symmetry energy as a response of the nuclear system to small isospin imbalance from the Z = N nuclei and pure neutron matter.
To explain the experimental observation that the fusion cross-section of a proton-halo nucleus with a heavy target nucleus is not enhanced as expected, the shielding hypothesis was proposed, where the proton-halo nucleus is polarized and the valence proton shielded by the core. In the frame of the improved quantum molecular dynamics model, the fusion reaction 17F on 208Pb around the Coulomb barrier is simulated. The existence of the shielding effect is verified by the microscopic dynamics simulations. Its influence on the effective interaction potential is also investigated.
We investigate the
The complex-scaled Green's function (CGF) method is employed to explore the single-proton resonance in 15F. Special attention is paid to the first excited resonant state 5/2+, which has been widely studied in both theory and experiments. However, past studies generally overestimated the width of the 5/2+ state. The predicted energy and width of the first excited resonant state 5/2+ by the CGF method are both in good agreement with the experimental value and close to Fortune's new estimation. Furthermore, the influence of the potential parameters and quadruple deformation effects on the resonant states are investigated in detail, which is helpful to the study of the shell structure evolution.
We derive a simple Woods-Saxon-type form for potentials between
In this paper a pair of observables are proposed as alternative ways, by examining the fluctuation of net momentum-ordering of charged pairs, to study the charge separation induced by the Chiral Magnetic Effect (CME) in relativistic heavy ion collisions. They are, the out-of-plane to in-plane ratio of fluctuation of the difference between signed balance functions measured in pair’s rest frame, and the ratio of it to similar measurement made in the laboratory frame. Both observables have been studied with simulations including flow-related backgrounds, and for the first time, backgrounds that are related to resonance's global spin alignment. The two observables have similar positive responses to signal, and opposite, limited responses to identifiable backgrounds arising from resonance flow and spin alignment. Both observables have also been tested with two realistic models, namely, a multi-phase transport (AMPT) model and the anomalous-viscous fluid dynamics (AVFD) model. These two observables, when cross examined, will provide useful insights in the study of CME-induced charge separation.
Heavy quarks play an important role in probing the properties of strongly interacting quark-gluon plasma (QGP) created in ultra-relativistic heavy-ion collisions. We study the interactions of single heavy (charm) quarks and correlated charm and anticharm (
We study quasinormal modes (QNMs) of charged black holes in the Einstein-Maxwell-Weyl (EMW) gravity by adopting the test scalar field perturbation. We find that the imaginary part of QNM frequencies is consistently negative for different angular parameters l, indicating that these modes always decay and are therefore stable. We do not observe a linear relationship between the QNM frequency ω and parameter p for these black holes, as their charge Q causes a nonlinear effect. We evaluate the massive scalar field perturbation in charged black holes and find that random long lived modes (i.e., quasiresonances) could exist in this spectrum.
- A SCOAP3 participating journal - free Open Access publication for qualifying articles
- Average 24 days to first decision
- Fast-track publication for selected articles
- Subscriptions at over 3000 institutions worldwide
- Free English editing on all accepted articles
- Happy New Year !
- 2019 CPC Top Reviewer Awards
- The 2019 National Day closure
- Editor Recruitment
- CPC authorship won the âIOP Publishing awards top cited Chinese authorsâ