International Journal of Modern Physics A

The role of preferred frames for light propagation and time dilation in the region of a massive, spherical, gravitating bodies, where according to general relativity, space–time curvature is described by the Schwarzschild metric equation, is discussed in the context of the Sagnac effect (for light propagation) and the Hafele–Keating experiment (for time dilation). Predictions for both translational and rotational motion relative to the preferred frame are calculated up to order ${(v/c)}^3$. Different published theoretical calculations of the Sagnac effect are critically reviewed. The conflation in the literature of measured time differences in Sagnac experiments (a classical order $v/c$ effect) and time dilation (a relativistic order ${(v/c)}^2$ effect) are also discussed.

In this paper, we review inflationary cosmology in M-theory with quantum corrections. In old days the inflation was proposed as a resolution to the cosmological problems, and nowadays models of the inflation are severely restricted by the observations. Among them, the predictions of the Starobinsky model, which contains scalar curvature squared term, is consistent with the observations. The higher curvature terms will come from quantum effect of the gravity, and it is natural to ask its origin in superstring theory or M-theory. We investigate inflationary solution in the M-theory with higher curvature terms. We show that higher curvature terms induce an exponentially expanding solution in the early universe, and the inflation naturally ends when the corrections are suppressed. We also discuss that the ambiguity of the higher curvature terms do not affect the inflationary scenario in the M-theory.

Production of quarks and gluons in hadron collisions tests Quantum Chromodynamics (QCD) over a wide range of energy. Models of QCD are implemented in event generators to simulate hadron collisions and evolution of quarks and gluons into jets of hadrons. pythia8 uses the parton shower model for simulating particle collisions and is optimized using experimental observations. Recent measurements of event shape variables and jet cross-sections in $pp$ collisions at $\surd s=13$ TeV at the Large Hadron Collider have been used to optimize the parton shower model as used in PYTHIA8.

This work has investigated the outcomes of spherically symmetric radiating dissipative gravitational collapse model with anisotropic heat conducting matter distribution by imposing time-dependent Karmarkar condition in the alternative $f(R)$ theory of gravity. For this evaluation, we defined the smooth matching conditions between the interior space–time and exterior Vaidya solution at the junction interface. Afterwards, we have found an exact particular solution of our radiative star model by using the Karmarkar condition. Moreover, the physical components of the matter distribution, energy conditions and time relaxational effects on the temporal profile are thoroughly discussed with graphical analysis which indicates the system is well behaved.

We investigate the $\beta$-deformed Gaussian Hermitian and $N\times N$ complex matrix models which are defined as the eigenvalue integral representations. Their $W_{1+\infty }$ constraints are constructed such that the constraint operators yield the same $W_{1+\infty }$$n$-algebra. When particularized to the Virasoro constraints in the $W_{1+\infty }$ constraints, the corresponding constraint operators yield the Witt algebra and null 3-algebra. By solving our Virasoro constraints, we derive the formulas for correlators in these two $\beta$-deformed matrix models, respectively.

We extend our recent works on the resonant state $D_0^{\ast }(2400)$ in the quasi-two-body $B_{(s)}$ meson decays to the $B_c$ cases within the perturbative QCD approach. With the help of the two-meson distribution amplitudes, we calculate the $CP$-averaged branching fractions and direct $CP$ violations of the quasi-two-body decays $B_c\to {\eta }_c(1S,2S)D_0^{\ast +}(2400)\to {\eta }_c(1S,2S)D^0{\pi }^{+}$ in this work. We also present the $D\pi$ invariant mass dependence of the differential branching fraction for the considered decay modes. Our results could be tested by further experiments in the LHCb.

We study the dependence of the observable stochastic gravitational wave background induced by a first-order phase transition on the global properties of the scalar effective potential in particle physics. The scalar potential can be that of the Standard Model Higgs field, or more generally of any scalar field responsible for a spontaneous symmetry breaking in beyond-the-Standard-Model settings that provide for a first-order phase transition in the early universe. Characteristics of the effective potential include the relative depth of the true minimum $(E_{\alpha }^4)$, the height of the barrier that separates it from the false one $(E_m^4)$ and the separation between the two minima in field space $(v)$, all at the bubble nucleation temperature. We focus on a simple yet quite general class of single-field polynomial potentials, with parameters being varied over several orders of magnitude. It is then shown that gravitational wave observatories such as aLIGO O5, BBO, DECIGO and LISA are mostly sensitive to values of these parameters in the region $E_{\alpha }\sim (0.1\text{–}10)\times E_m$. Finally, relying on well-defined models and using our framework, we demonstrate how to obtain the gravitational wave spectra for potentials of various shapes without necessarily relying on dedicated software packages.

From the mass textures’ point of view, we present a comparative study of the $S_3$ flavor symmetry in the left–right symmetry model (LRSM) and the baryon minus lepton model (BLM) taking into account their predictions on the CKM mixing matrix. To do this, we recover the already studied quark mass matrix, that comes from some published papers, and under certain strong assumptions, one can show that there are predictive scenarios in the LRSM and BLM where the modified Fritzsch and nearest neighbor interaction (NNI) textures drive, respectively, the quark mixings. As the main result, the CKM mixing matrix is in good agreement with the last experimental data in the flavored BLM model.

In this paper, we examine the Ruelle-type spectral functions ${ℛ}(s)$, which define an overall description of the content of the work. We investigate the Gopakumar–Vafa reformulation of the string partition functions, describe the $N=2$ Landau–Ginzburg model in terms of Ruelle-type spectral functions. Furthermore, we discuss the basic properties satisfied by elliptic genera in $N=2$ theories, construct the functional equations for ${ℛ}(s)$, and analyze the modular transformation laws for the elliptic genus of the Landau–Ginzburg model and study their properties in details.

Opportunity of the solar flares (SFs) prediction observing the solar neutrino fluxes is investigated. In three neutrino generations, the evolution of the neutrino flux traveling the coupled sunspots (CSs) which are the SF source is considered. It is assumed that the neutrinos possess both the dipole magnetic moment and the anapole moment while the magnetic field above the CSs may reach the values $10^5\text{–}10^6$ Gs, display the twisting nature and posses the nonpotential character. The possible resonance conversions of the solar neutrino flux are examined. Since the ${\nu }_{eL}\to {\nu }_{\mu L}$ resonance takes place before the convective zone, its existence can in no way be connected with the SF. However, when the solar neutrino flux moves through the CSs in the preflare period, then it may undergo the additional resonance conversions and, as a result, depleting the electron neutrinos flux may be observed.

We calculate the quasi-uniform gravitational field of a disk in the weak-field approximation and demonstrate an inappropriateness of preceding results. The Riemann tensor of this field is determined. The nonexistence of the uniform gravitational field is proven without the use of the weak-field approximation. The previously found difference between equations of motion for the momentum and spin in the accelerated frame and in the quasi-uniform gravitational field also takes place for the disk. However, it does not violate the Einstein equivalence principle because of the nonexistence of the uniform gravitational field.

The interaction of an electron with a nonuniform axial magnetic field is analyzed in a uniformly rotating frame. In particular, the magnetic field is proportional to the square of the radial distance from the symmetry axis. Then, in search of analytical solutions to the Schrödinger equation, it is shown that these solutions are possible if the nonuniform magnetic field possesses a discrete set of values.

In earlier work we analyzed an abelianized model in which a gauged Rarita–Schwinger spin-$\frac{3}{2}$ field is directly coupled to a spin-$\frac{1}{2}$ field. Here, we extend this analysis to the gauged $SU(8)$ model for which the abelianized model was a simplified substitute. We calculate the gauge anomaly, show that anomaly cancellation requires adding an additional left chiral representation $\bar{8}$ spin-$\frac{1}{2}$ fermion to the original fermion complement of the $SU(8)$ model, and give options for restoring boson–fermion balance. We conclude with a summary of attractive features of the reformulated $SU(8)$ model, including a possible connection to the $E_8$ root lattice.