Modern Physics Letters A

By using the minimal extension of the standard model and considering the general relativistic effects near the surface of a static neutron star in the presence of quintessence fields, we drive analytical expressions for the cross-section and energy deposition rate of the process (${\nu }_e+{\overline{\nu }}_e\to (W,Z,\gamma )\to e^{-}+e^{+}$). We have also obtained the ratio of energy deposition to total Newtonian energy deposition ($\dot{Q}∕{\dot{Q}}_{\mathrm{\text{Newt}}}$). We have displayed that the contributions of the electron neutrino’s charge radius are more effective than the dipole moment in this process. The obtained solutions indicate that the contribution of the electron neutrino charge radius changes the results approximately (1–5)% depending on the $\frac{R}{M}$ value of the star.

In this paper, we have analyzed the proton form factor data by using a number of phenomenological parametrizations (models) and extracting the proton electric and magnetic radii. To this end, we performed a global fit to all available form factor data, with the virtual photon momentum squared $Q^2$ from $0.0002$ to nearly 10GeV² for electric form factor and from $0.015$ to 31GeV² for magnetic one. Special attention was given to the small structure shown by the form factor data near $Q^2=0.2$GeV². It was found that different models yield different structures with different numbers of minimum at this kinematics. Since the slope of form factor in the limit of $Q^2\to 0$ is influenced by this structure, the extracted proton radii are consequently different for different models. Our finding recommends that future experiments should focus on this kinematics instead of low $Q^2$. Experimental data with accuracies comparable to those of the latest data at low $Q^2$ would clearly help to clarify the effect of this structure on the proton charge radius. Interestingly, most of the extracted proton charge radii were found to be closer to the value obtained from the muonic hydrogen atom spectroscopy.

For two operators $X$ and $Y,$ which obey

In this paper, we review the concept of charge and chirality for particles and antiparticles. We point out that the commonly accepted equivalence of particles and antiparticles—with difference only in the opposite signs of their charges, which follows from the CPT invariance—is valid only for free non-chiral particles. We point out that the the equivalence of particles and antiparticles is violated if the weak interaction is turned on. We also discuss that within the standard model even free neutrinos are exceptions, as they can be produced only in chiral states. We conclude that in spite of a long history of antiparticles, interesting theoretical and experimental challenges remain in their complete understanding.

The Rayleigh–Schrodinger method or more commonly called time independent perturbation theory is a powerful method to solve a Hamiltonian system with a relatively small perturbation [W. Nolting, Theoretical Physics 7: Quantum Mechanics–Methods and Applications (Springer International, 2017); F. Schwabl, Quantum Mechanics, 4th edn. (Springer, 2007)]. In this work, we make use of the Rayleigh–Schrodinger method to formulate a general method to calculate quasibound states of static spherically symmetric black hole solutions arising from modified theories of gravity. We discover that the Schwarzschild-like term corresponds to the main Hamiltonian while the modified theory of gravity’s contribution of the spacetime metric corresponds to the perturbation terms. At the end, formula to calculate main Hamiltonian and perturbed Hamiltonian are discovered and presented.

An approach that allows studying the relationship between the neutralization of the cosmological constant and instantons for cosmology coupled to antisymmetric fields is proposed. Using suitable variables, the Lagrangian leading to the FRW equations can be written analogously to a Ginzburg–Landau theory, and we show how spontaneous symmetry breaking appears.

In this paper, the modified Dirac equation (MDE) has been solved approximately for improved Manning–Rosen plus quasi-Hellman potentials (IMRQHPs), including the improved Yukawa tensor interaction under new spin symmetry and pseudospin symmetry for arbitrary spin–orbit number $k$, an appropriate approximation employed on the centrifugal terms in the symmetries of three-dimensional extended relativistic quantum mechanics (3D-ERQM). This potential is a superposition of Manning–Rosen plus quasi-Hellman potentials and some other exponential terms. Through the application of both new approximations to deal with the centrifugal term, Bopp’s shift method and the independent-time perturbation theory method, the recent modified approximate energy corrections under IMRQHPs are obtained for nuclei ${}^{17}$O and ${}^{17}$F and (O₂, I₂, N₂, H₂, LiH, CO and NO) diatomic molecules in 3D-ERQM and three-dimensional extended non-relativistic quantum mechanics (3D-ENRQM) symmetries. The recent values that we get appear sensitive to $(j,k,l∕\tilde{l},s∕\tilde{s},m∕\tilde{m})$, which are known as the discrete atomic quantum numbers, the mixed potential depths ($C∕A$, $D∕B$) and $(V_0∕a,V_1∕b)$, the range of the potential $\alpha$ and non-commutativity parameters $(\mathrm{\Theta },\sigma ,\chi )$. In both 3D-ERQM and 3D-ENRQM symmetries, we show that the recent corrections obtained on the new bound states under IMRQHPs are infinitesimal to the principal part of energy in the ordinary cases of 3D-RQM and 3D-NRQM symmetries. In the new symmetries of 3D-ERQM symmetries, it is not possible to get the exact analytical solutions $k=1$ and $k\ne -1$, only the approximate solutions are possible. In addition, we discussed in detail the non-relativistic study of the studied mixed potentials. Four special cases, i.e. we investigated some special cases in the context of modified Schrödinger theories. In the framework of known relativistic quantum mechanics, we have clearly demonstrated that the modified Schrödinger equation can be represented as the Dirac equation under the influence of IMRQHPs.

About 12 years ago, the use of standard functional manipulations was demonstrated to imply an unexpected property satisfied by the fermionic Green’s functions of QCD. This non-perturbative phenomenon is dubbed Effective Locality. In a much simpler way than in QCD, the most remarkable and intriguing aspects of Effective Locality are presented here, in the Yang–Mills theory on Minkowski spacetime.