Modern Physics Letters A

We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a type-I Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.

Scale factor matrices relating mesonic fields in chiral Lagrangians and quark-level operators of QCD sum-rules are shown to be constrained by chiral symmetry, resulting in universal scale factors for each chiral nonet. Built upon this interplay between chiral Lagrangians and QCD sum-rules, the scale factors relating the $a_0$ isotriplet scalar mesons to their underlying composite quark fields were recently determined. It is shown that the same technique when applied to $K_0^{\ast }$ isodoublet scalars reproduces the same scale factors, confirming the universality property and further validating this connection between chiral Lagrangians and QCD sum-rules, which can have nontrivial impacts on our understanding of the low-energy QCD, in general, and the physics of scalar mesons in particular.

We investigate the charged particle spectra produced in the heavy-ion collisions at nine centralities from different systems, i.e. $\mathrm{\text{Pb}}+\mathrm{\text{Pb}}$ at $\sqrt{s_{NN}}=2.76$ TeV and 5.02 TeV as well as $\mathrm{\text{Xe}}+\mathrm{\text{Xe}}$ at $\sqrt{s_{NN}}=5.44$ TeV, at Large Hadron Collider (LHC) using one empirical formula inspired by the stationary solution of the Fokker-Planck equation, dubbed as the generalized Fokker-Planck solution (GFPS). Our results show that the GFPS can reproduce the experimental particle spectrum up to transverse momentum $p_T$ about 45 GeV/c with the maximum discrepancy 30% covering 10 orders of magnitude. The discrepancy between the data and the results from the GFPS decreases to 15% when the maximum of the charged particle transverse momentum is cut to 20 GeV/c. We confirmed that the Tsallis distribution derived from the non-extensive statistics, which can reproduce the particle spectra produced in small collision systems, such as $\mathrm{\text{p}}+\mathrm{\text{p}}$, up to few hundreds GeV/c, can only apply to systematically study the particle spectra up to 8 GeV/c in $\mathrm{\text{A}}+\mathrm{\text{A}}$ collisions at LHC, as pointed out in the study of identified particle spectra in $\mathrm{\text{Pb}}+\mathrm{\text{Pb}}$ collisions at $\sqrt{s_{NN}}=2.76$ TeV. A brief discussion on GFPS is also given.

We show that the bootstrapped Newtonian potential generated by a uniform and isotropic source does not depend on the one-loop correction for the matter coupling to gravity. The latter, however, affects the relation between the proper mass and the Arnowitt–Deser–Misner (ADM) mass and, consequently, the pressure needed to keep the configuration stable.

Recently, Hod showed that neutral stationary scalar field clouds can exist outside neutral reflecting compact stars. In the present paper, we extend the discussion by considering charged stationary scalar fields in the background of charged reflecting compact stars. If stationary scalar clouds exist, we analytically show that the field frequency belongs to an interval. For certain discrete field frequency values in the interval, we obtain numerical solutions of scalar field clouds. We also study effects of model parameters on discrete frequency.

In this paper, we examine the existence of Bianch type I Brans–Dicke universe by performing statistical test from $H(z)$ and SN Ia observational data sets. We find that anisotropic Brans-Dicke ($\sigma$ BD) model provides a reasonable fit with observational data. In addition to ${\chi }^2$, we also use Akaike information creation (AIC) and Bayes information creation (BIC) to determine the values of best fit parameters. The model under consideration represents a transitioning universe from early decelerating phase to current accelerating phase. We obtain the present age of the universe as 13.732 Gyrs, which is in good agreement with WMAP observations. The physical behavior of particle horizon and $Om(z)$ parameter of the derived model are also discussed.

In this paper, we use the functional Bethe ansatz method to solve the radial problem of the Dirac oscillator in cosmic string space-time, and its general solution under the Killingbeck potential plus isotonic oscillator potential in the limit of the spin and the pseudo-spin symmetries are further presented. Corresponding to the expressions of energies and wave function of bound state and first excited state are given. Furthermore, some particular cases including the Cornell potential, the Kratzer potential, the Killingbeck potential and the isotonic oscillator potentials are also addressed. It shows that the energy levels of the systems depend explicitly on the potential parameters $A$, $B$, $C$, $D$, $F$, $G$ and the angular deficit parameter $\alpha$ which characterize topological defect.

Due to the high security of quantum transmission and the more flexible and economical implementation of wireless communication, quantum wireless network communication attracts lots of attention. Because of the high entanglement persistence and robustness of cluster states against decoherence and loss, we investigate the application of cluster states in quantum wireless network communication (QWNC) and propose several kinds of QWNC schemes based on 1D, 2D and 3D cluster states, respectively. Finally we propose a QWNC scheme under the bilayer quantum network architecture. Comparing with other multi-hop teleportation schemes, it is unnecessary for the intermediate nodes to perform entanglement swapping to establish the required entanglement. The computational complexity is independent of the number of intermediate nodes and cluster states are allocated on demand, thus reducing the computational complexity and resource consumption largely.

In the model with Chern-Simons potential describing the coupling of electromagnetic field with a two-dimensional material, the possibility of the appearance of bound field states, vanishing at sufficiently large distances from interacting with its macro-objects, is considered. As an example of such two-dimensional material object we consider a homogeneous isotropic plane. Its interaction with electromagnetic field is described by a modified Maxwell equation with singular potential. The analysis of their solution shows that the bound state of field cannot arise without external charges and currents. In the model with currents and charges the Chern-Simons potential in the modified Maxwell equations creates bound state in the form of the electromagnetic wave propagating along the material plane with exponentially decreasing amplitude in the orthogonal to its direction.