International Journal of Modern Physics A

Numerical simulations of three and four top quark hadroproduction processes are carried out in the SMEFT model framework. The simulated data are used to derive expected theoretical constraints on Wilson coefficients of relevant SMEFT operators of dimension six. Obtained limits for both cases are discussed and compared in terms of processes’ sensitivity to possible BSM contribution. Results show that operator $O_{tt}^1$ is better constrained by the process of four top quark production, whereas other four operators $O_{QQ}^1$, $O_{Qt}^1$, $O_{Qt}^8$ and $O_{QQ}^8$, are similarly constrained in three and four top quark production processes. In all cases, the expected limits taken from the simultaneous analysis of the production of three and four top quarks are strengthened. Analytical expressions for the partial amplitudes of the processes $tt\to tt$ and $t\bar{t}\to t\bar{t}$ caused by the operators $O_{tt}^1$, $O_{QQ}^1$, $O_{Qt}^1$, $O_{Qt}^8$, $O_{QQ}^8$ were obtained for the first time. Based on the expressions of the obtained partial amplitudes, graphs of the perturbative unitarity boundary for the listed operators were drawn. The question of how kinematic cuts motivated by partial unitarity affect the resulting constraints on the Willson coefficients is addressed. It is shown that in all cases the limits are getting somewhat worse if such cuts are applied.

It is important to consider the charged current weak interaction in the (semi-)inclusive deeply inelastic scattering to determine (transverse momentum dependent) parton distribution functions with flavor identifications. To this end, we calculate the charged current semi-inclusive deeply inelastic neutrino and anti-neutrino nucleus scattering and propose a measurable quantity in this paper to determine the transverse momentum dependent parton distribution functions. Semi-inclusive means that an unpolarized or a spin-0 hadron is detected in the current fragmentation region in addition to the scattered charged lepton. The target nucleus is assumed to be spin-1 for the complete calculation. We find that only the chiral-even terms survive and the chiral-odd terms vanish in this charged current deeply inelastic (anti-)neutrino nucleus scattering process. The measurable quantity is the yield difference or asymmetry of the positive pion and the negative pion. We notice that it is only determined by (anti-)strange quark distribution functions under isospin symmetry and would be reduced to a function of kinematic variable y if (anti-)strange quark distribution functions are neglected. The kaon meson production can be discussed in a similar way. Our calculations are limited at the leading twist level.

In this paper, we present the construction and analysis of an interior solution for a compact star in Rastall gravity. The space–time considered is static and spherically symmetric, meanwhile, the source of matter is that of a perfect fluid. The solution of the equations system which describes the model is obtained from a specific form of the red shift factor function and its result is physically acceptable. The analysis of the solution is focused on the description of the star PSR $\mathrm{\text{J}}0348+0432$, for which we know the observational data of mass $M=(2.01\pm 0.04)M_{\odot }$ and radius $R=(12.5095\pm 0.4475)$km, a comparison with the behavior of the solution in the frame of Einstein’s general relativity theory, $\lambda =1$, shows that for $\lambda >1$ the density, pressure and speed of sound are greater, meanwhile for $\lambda <1$ their values are lower. The analysis of the generalized TOV equation to the case of the Rastall gravity implies that the contribution of the force associated to the Rastall parameter can generate an attractive ($\lambda >1$) or repulsive ($\lambda <1$) force, showing the relevance and the effect that the Rastall parameter has in stellar models.

This paper investigates the Page curve in warped anti-de Sitter black holes using the “quantum extremal surface” prescription. The findings reveal that in the absence of an island, the entanglement entropy of Hawking radiation grows proportionally with time and becomes divergent at later times. However, when considering the island’s emergence, which extends slightly beyond the event horizon, the growth of the entanglement entropy of Hawking radiation comes to a constant value. Eventually, the constant value is precisely twice the Bekenstein–Hawking entropy. We have also discussed the Page time and the scrambling time.

The modular $A_4$ symmetry with three moduli is investigated. We assign different moduli to charged leptons, neutrinos, and quarks. We analyze these moduli at their fixed points where a residual symmetry exists. We consider two possibilities for right-handed neutrinos. First, they are assumed to be singlets under the modular symmetry. In this case, we show that the lepton masses and mixing can be obtained consistently with experimental observations. Second, they are assigned nontrivially under modular symmetry. We emphasize that a small deviation from their fixed point is required in this case. Finally, the quark masses and mixing are generated correctly around the fixed point of their modulus. In our analysis, we only consider the simple case of weight 2.

The Lorentz transformation describes differential simultaneity, which reflects the offsetting of time with distance between reference frames. Differential simultaneity is essential for Lorentz invariance. Here, the current experimental support for differential simultaneity is assessed. Differential simultaneity can be mathematically removed from the Lorentz transformation to produce an alternate transformation that describes relativistic effects in the absence of differential simultaneity. Differential simultaneity is shown to be required for Lorentz symmetry. The alternate transformation is used as a contrast for the Lorentz transformation to assess whether relativistic experiments provide definitive evidence for differential simultaneity. If the alternate transformation is compatible with an experiment, then the experiment does not provide definitive evidence for differential simultaneity because it can be explained in the absence of differential simultaneity. Here, the alternate transformation is shown to be compatible with the broad array of current relativistic experiments. This implies that current experiments do not provide definitive evidence for differential simultaneity. Thus, an essential aspect of Lorentz symmetry currently lacks definitive experimental support.

At the Large Hadron Collider (LHC), ATLAS and CMS collaborations observed various decay modes of the light charged Higgs bosons produced by top (anti)quark decays. In this paper, we are interested in the subsequent decay of the light charged Higgs boson into a charm and a strange quark–antiquark pair and into a tau and a tau–neutrino pair, separately, in the context of the Georgi–Machacek model, which offers a large triplet vacuum expectation value (VEV) preserving custodial symmetry. We show that these experimental observations constrain the triplet VEV from above. We explore the model parameter space consistent with the theoretical constraints, the latest Higgs data and the experimental data for light charged Higgs decaying to $cs$ and $\tau {\nu }_{\tau }$.

In this paper, we propose a construction to compute the holographic entanglement negativity (HEN) for bipartite mixed state configurations of two disjoint subsystems in higher-dimensional conformal field theories (CFT_ds) dual to bulk AdS${}_{d+1}$ geometries. Our proposal follows from the corresponding AdS₃/CFT₂ scenario and involves an algebraic sum of the areas of bulk RT surfaces for certain combinations of subsystems. By utilizing our construction, we compute the HEN at the leading order through a perturbative expansion, for such bipartite mixed states of two disjoint subsystems with long rectangular strip geometries in CFT_ds dual to bulk pure AdS${}_{d+1}$ geometries and AdS${}_{d+1}$-Schwarzschild black holes.

In this work, I study the Casimir effect caused by a charged and massive scalar field that violates Lorentz symmetry in an aether-like and CPT even manner, by direct coupling between the field derivatives and two fixed orthogonal unit vectors. I call this a “double” Lorentz violation. The field will satisfy either Dirichlet or mixed boundary conditions on a pair of plane parallel plates. I use the generalized zeta function technique to examine the effect of a uniform magnetic field, perpendicular to the plates, on the Casimir energy and pressure. Three different pairs of mutual directions of the unit vectors are possible: timelike and spacelike perpendicular to the magnetic field, timelike and spacelike parallel to the magnetic field, spacelike perpendicular and spacelike parallel to the magnetic field. I fully examine all of them for both types of boundary conditions listed above and, in all cases and for both types of boundary conditions, I obtain simple expressions of the zeta function, Casimir energy and pressure in the three asymptotic limits of strong magnetic field, large mass, and small plate distance.

Motivated by the significance of modular symmetry in generating neutrino masses and flavor mixings, we apply the modular $A_4$ symmetry in a $3+1$ scheme of active–sterile neutrino mixings. Neutrino oscillation observables in the 3$\sigma$ range are successfully reproduced through the vacuum expectation value of the modulus $\tau$. We also study phenomenologies related to the effective neutrino masses $m_{\beta }$ in tritium beta decay and $m_{\beta \beta }$ in neutrinoless double beta decay. Mixings between active neutrinos and eV scale sterile neutrino are analyzed in detail. The model also predicts the Dirac CP-violating phase ${\delta }_{\mathrm{\text{CP}}}$ and Majorana phases $\alpha$ and $\beta$. The best-fit values of the neutrino mixing angles and ratios of two mass-squared differences are determined using minimum ${\chi }^2$ analysis. The best-fit values of the neutrino oscillation observables are predicted as ${sin}^2{\theta }_{23}=0.573,$ ${sin}^2{\theta }_{12}=0.300,$ ${sin}^2{\theta }_{13}=0.022$ and $r=0.172$ for NH while ${sin}^2{\theta }_{23}=0.550,$ ${sin}^2{\theta }_{12}=0.303,$ ${sin}^2{\theta }_{13}=0.022$ and $r=0.171$ for IH. We also observe that the predictions of effective neutrino mass parameters in the $3+1$ scheme are significantly different from the three neutrino paradigm.

In this study, we explore various essential aspects of a noncommutative theory that incorporates space deformation. Through the Extended Gravitational Decoupling (EGD) approach within the Strong Energy Condition (SEC), we investigate the gravitational decoupling method to obtain static black hole solutions that satisfy Einstein’s field equations with a vacuum tensor. The analysis concentrates on the thermodynamics of the static solution, examining and deriving expressions for various thermodynamic quantities. This investigation explores how temperature, free energy, and specific heat depend on the horizon radius, considering different values for both hairy and noncommutative parameters. The study suggests that thermodynamically, smaller hairy black holes exhibit greater stability compared to larger ones. It also reveals a nontrivial relationship between the horizon radius, temperature range, and specific values of the hairy parameters for static hairy black holes when considered in thermodynamic equilibrium with their Hawking radiation. The discussion extends to the implications of the first law of black hole thermodynamics in the context of the noncommutative hairy case.

We construct closed-form solutions to the one-dimensional, stationary Dunkl–Schrödinger equation for the inverted oscillator potential with an inverse quadratic singularity at the origin. Conditions are derived for our solutions to represent bound states, and an example is given.