International Journal of Modern Physics A

Today, the original Michelson–Morley experiment and its early repetitions at the beginning of the 20th century are considered as a venerable historical chapter for which, at least from a physical point of view, there is nothing more to refine or clarify. The emphasis is now on the modern versions of these experiments, with lasers stabilized by optical cavities, that, apparently, have improved by many orders of magnitude on the limits placed by those original measurements. Though, in those old experiments light was propagating in gaseous systems (air or helium at atmospheric pressure) while now, in modern experiments, light propagates in a high vacuum or inside solid dielectrics. Therefore, in principle, the difference might not depend on the technological progress only but also on the different media that are tested by preventing a straightforward comparison. Starting from this observation, one can formulate a new theoretical scheme where the tiny, irregular residuals observed so far, from Michelson–Morley to the present experiments with optical resonators, point consistently toward the long sought preferred reference frame tight to the Cosmic Microwave Background (CMB). The existence of this scheme, while challenging the traditional ‘null interpretation’, presented in all textbooks and specialized reviews as a self-evident scientific truth, further emphasizes the central role of these experiments for Relativity, Cosmology and Quantum Physics.

A new CDF II measurement of the $W$-boson mass indicated a 7$\sigma$ deviation from the Standard Model (SM) prediction, and the previous FNAL and BNL measurement of muon ($g$-2) showed a 4.2$\sigma$ deviation from the SM prediction. As a result, new physics beyond the SM is indicated. In this paper, parameter space is scanned in the $\mu$-term extended Next-to-Minimal Supersymmetric Standard Model ($\mu$NMSSM). We get the surviving samples considering the limitations from the Large Hadron Collider (LHC) experiment and the Dark Matter (DM) direct detection experiment. In addition, we study phenomenon of $W$-boson mass and muon magnetic moment for them. Finally, we find that it is difficult to obtain samples surviving constraints of both CDF II experiment and muon anomaly magnetic in the $\mu$NMSSM.

Motivated by the deviation of the $W$-boson mass reported by the CDF collaboration, we study an extension of the Standard Model (SM) including a vector dark matter (VDM) candidate and a scalar mediator. In the model, the one-loop corrections induced by the new scalar shift the $W$-boson mass. We identify the parameter space of the model consistent with dark matter (DM) relic abundance, $W$-mass boson anomaly, invisible Higgs decay at LHC, and direct detection of DM. It is shown that the $W$-mass anomaly can be explained for the large part of parameter space of VDM mass and scalar mediator mass between 100GeV and 124GeV by the model. We also investigate the renormalization group equations (RGEs) at one-loop order for the model. We show that the contribution of new scalar mediator to RGE guarantees positivity and vacuum stability of SM Higgs up to Planck scale.

The recent high precision measurement of $W$ boson mass by CDF-II collaboration points to the contribution(s) of new physics beyond the Standard Model (SM). One of the minimalistic ways to account for the anomalous $W$ boson mass is by introducing a hyperchargeless real $\mathrm{\text{SU}}{(2)}_L$ triplet scalar whose vacuum expectation value (VEV) explicitly contributes to the $W$ boson mass at the tree level while the $Z$ boson mass remains the same. Such a triplet can be naturally embedded in a singlet-triplet scotogenic model for one-loop neutrino mass generated by dark sector particles running in the loop. We discuss the detailed phenomenology of the model, obtaining the parameter space consistent with the CDF-II $W$ boson mass measurements. The dark matter as well as the constraints comings from $S$, $T$, $U$ parameters are also analyzed.

The CDF II measurement of $W$ boson mass is at significant ($6.9\sigma$) tension with the Standard Model, and moderate ($4.0\sigma$) tension with recent results from ATLAS. Any attempt to interpret this as a signature of new physics requires high-precision, robust, falsifiable predictions. The Classical Analogue to the Standard Model In pseudo-Riemannian space–time (CASMIR) is an analogue model predicting $W$ and $Z$ boson masses of $80.3587(22)\mathrm{\text{GeV}}/c^2$ and $91.1877(35)\mathrm{\text{GeV}}/c^2$, respectively. During baryon collisions satisfying $\sqrt{s}<3.09\mathrm{\text{TeV}}$, CASMIR predicts a color-mediated enhancement of $W$ and $Z$ boson masses, becoming $80.4340(22)\mathrm{\text{GeV}}/c^2$ and $91.1922(35)\mathrm{\text{GeV}}/c^2$, respectively. The unenhanced masses are consistent with ATLAS data collected at $\sqrt{s}=7\mathrm{\text{TeV}}$, and the enhanced masses are consistent with CDF II data collected at $\sqrt{s}=1.96\mathrm{\text{TeV}}$. According to CASMIR, operation of the Large Hadron Collider (LHC) at center-of-mass energies small compared with $3.09\mathrm{\text{TeV}}$ but large enough for $W$ boson formation should permit ATLAS to replicate the result from CDF II.

In this paper, we study the dominant nonuniversal contributions to muon decay for the five scalar leptoquarks (LQs) allowed by the Standard Model gauge symmetries. By using a common computational framework, we isolate the New-Physics (NP) one-loop corrections over the observable $\mathrm{\Delta }r$ and explore the connection with the W boson mass. We highlight the role of nonuniversal terms considering, for the $\mathrm{\text{SU}}(2)$ doublet and triplet LQs, a completely degenerate scenario, thus cancelling/moderating the effects of the oblique parameters S, T and U. We determine simple formulas that exhibit the leading nonuniversal behavior generated by the introduction of extra Yukawa terms and confront them against a present tension in $M_W$ and the projected FCC-ee accuracy.

The framed standard model (FSM), constructed to explain, with some success, why there should be three and apparently only three generations of quarks and leptons in nature falling into a hierarchical mass and mixing pattern, suggests also, among other things, a scalar boson U, with mass around 17 MeV and small couplings to quarks and leptons, which might explain the $g-2$ anomaly reported in experiment. The U arises in FSM initially as a state in the predicted “hidden sector” with mass around 17MeV, which mixes with the standard model (SM) Higgs $h_W$, acquiring thereby a coupling to quarks and leptons and a mass just below 17MeV. The initial purpose of this paper is to check whether this proposal is compatible with experiment on semileptonic decays of Ks and Bs where the U can also appear. The answer to this we find is affirmative, in that the contribution of U to new physics as calculated in the FSM remains within the experimental bounds, but only if $m_U$ lies within a narrow range just below the unmixed mass. As a result from this, one has an estimate $m_U\sim 15$–17MeV for the mass of U, and from some further considerations the estimate ${\mathrm{\Gamma }}_U\sim 0.02$eV for its width, both of which may be useful for an eventual search for it in experiment. If found, it will be, for the FSM, not just the discovery of a predicted new particle, but the opening of a window into a whole “hidden sector” containing at least some, perhaps even the bulk, of the dark matter in the universe.

In this paper, our principal objective is to investigate the impact of disclination and throat radius of a three-dimensional traversable wormhole on quantum oscillator fields. Specifically, we focus on Perry–Mann-type wormhole with disclination while also considering the influence of rainbow gravity’s. We derive the radial equation of the relativistic Klein–Gordon oscillator within this wormhole background under the effects of gravity’s rainbow and the analytical eigenvalue solution is obtained using the confluent Heun function. In fact, we show that the behavior of the oscillator fields is significantly influenced not only by the presence of disclination and the throat radius but also by the parameter of rainbow gravity’s. We choose various such rainbow functions to present and analyze the eigenvalue solutions of the quantum oscillator fields.

In this paper, the modified Hawking radiation and the P-v criticality of Reissner–Nordström-de Sitter (RNdS) black hole are investigated by using Dirac equation with Lorentz violation theory in curved space–time. Taking cosmological constant as the thermodynamic pressure and its conjugate quantity as thermodynamic volume, the analogy between the RNdS black hole in the ensemble with fixed charge and van der Waals liquid-gas system is derived. We also study the equation of state, critical exponents, critical point, heat capacity, entropy correction, Gibbs free energy. It is worth mentioning that the critical temperature, entropy, Gibbs free energy and Helmholtz free energy are modified but the critical exponents are found to be unchanged due to the influence of Lorentz violation theory. We observe that the number of Hawking–Page critical point increases due to Lorentz violation theory.

There is no evidence that the universe must have been homogeneous and isotropic before big bang nucleosynthesis. The Bianchi type-I cosmology is the simplest homogeneous but anisotropic cosmology. In this work, we investigate thermal leptogenesis, as a baryogenesis scenario, in the Bianchi type-I cosmology. Our results show that for specific values of the anisotropy, the modified thermal leptogenesis generated more baryon asymmetry than the standard one. In this way, anisotropy can help to achieve low-scale leptogenesis.

In this paper, we discuss exact realizations of the Yang–Poisson model on canonical phase space. The Yang model is an example of noncommutative geometry on a background space–time of constant curvature and is notable for its duality between position and momentum manifolds. We call Yang–Poisson model its classical limit, with commutators replaced by Poisson brackets. The structure is simpler in the classical case, and exact realizations can be found.

We find the nonextremal charged rotating charged black holes in quadratic $f(T)$ gravity are holographically dual to two different hidden conformal field theories. The two conformal field theories can be merged to find a very general hidden conformal field theory, which is generated by the $SL(2,\mathbb{Z})$ modular group. We also carry out the calculation to the extremal limit of the black holes, and find the corresponding dual quantities. Contrary to the existence of two different dual conformal field theories for the extremal charged rotating black holes in Einstein gravity, we find only one dual theory exists for the extremal charged rotating black holes in quadratic $f(T)$ gravity.

We extend our recent works [Int. J. Mod. Phys. A 38, 2350069 (2023)] and obtain one-parameter $(\lambda )$ family of rationally extended Dirac–Lorentz scalar potentials with their explicit solutions in terms of $X_m$ exceptional orthogonal polynomials. We further show that as the parameter $\lambda \to 0$ or $-1$, we get the corresponding rationally extended Pursey and the rationally extended Abraham–Moses-type of scalar potentials, respectively, which have one bound state less than the starting scalar potentials.

This study focuses on the cosmological evolution of Barrow holographic dark energy (BHDE) in a flat FLRW-universe. We take into account a time-dependent scale factor $a(t)={[sinh(kt)]}^{\frac{1}{n}}$, where k and n are positive values, to find the solutions to field equations. This scale factor results in a smooth transition of the universe from its previous decelerating stage to its most recent accelerating stage. Using the Granda–Oliveros cut-off, we examine the chronology of the deceleration parameter, equation of state parameter, and density parameter, and we analyze the positive aspects of the BHDE model. Negative pressure values in this model suggest dark energy dominance, resulting in the universe’s acceleration. We use the statefinder parameters ($r,s$) to improve the accuracy of the results of the dark energy model that is similar to the $\mathrm{\Lambda }$-CDM model.

In chiral Einstein–Cartan gravity, a new gauge fixing procedure is implemented recently, leading to a very economical perturbation expansion of the action. Using this formulation and the relevant gauge fixing, we develop the ghost Lagrangian on an arbitrary Einstein background using the Becchi-Rouet-Stora-Tyutin (BRST) formalism. The novelty is the appearance of a new term quadratic in the tetrad field. We next compute the heat kernel coefficients and understand the divergences arising in the gravitational one-loop effective action. In our computation, the arising heat kernel coefficients depend only on the self-dual part of the Weyl curvature. We make a comparison between our results and what has been obtained for metric general relativity.

We will highlight that despite there being various approaches to quantum gravity, there are universal approach-independent features of quantum gravity. The geometry of space–time becomes an emergent structure, which emerges from some purely quantum gravitational degrees of freedom. We argue that these quantum gravitational degrees of freedom can be best understood using quantum information theory. Various approaches to quantum gravity seem to suggest that quantum gravity could be a third quantized theory, and such a theory would not be defined in space–time, but rather in an abstract configuration space of fields. This supports the view that space–time geometry is not fundamental, thus effectively ending the space–time description of nature.

In Quantum Field Theory (QFT), scattering amplitudes are computed from propagators which, for internal lines, are built upon spin/polarization-sum relationships. In turn, these are normally constructed upon plane-wave solutions of the free field equations. A question that may now arise is whether such spin/polarization-sums can be generalized. In the past, there has been a first attempt at generalizing spin sums for fermionic fields in terms of the Michel–Wightman identities. In this paper, we aim to find the most general spin sums for fermionic fields within the range of QFT.

In this paper, we explore the noncommutative space–time to revive the idea that gamma-ray excess in the galactic center may stem from the annihilation of particle dark matter. In the noncommutative theory, the photon spectrum is produced by direct emission during this annihilation wherein a photon can be embed in the final state together with other direct products in new vertices. In the various configurations of dark matter phenomenology, we pursue the most prevalent model known as singlet scalar. Calculating the relevant aspects of the model and determining the parameters phase space, we derive the photon flux in the galactic center. This region, known for its high density and occasional existence of robust magnetic fields, serves as an ideal location for investigating theories that encompass the concept of Lorentz symmetry breaking. Upon comparing our numerical achievements with experimental data, it becomes evident that noncommutative space–time can be a reliable framework to explain the gamma-ray excess.

Axion Dark Matter (DM) is studied on the formation of SuperMassive Black Holes (SMBH) at high red shift z. It is shown that the attractive self-interaction of this DM may resolve the tension between the large mass with high angular momentum of SMBH and its early time formation. We consider the ultra-light axion DM around $O(10^{-21})$ eV as its origin, which may also cause nano-Hz stochastic gravitational wave background recently observed.

In this paper, we obtain a solution of a static spherically symmetric charged black hole inspired by noncommutative geometry in the context of the regularized 4D-Einstein–Gauss–Bonnet theory in AdS space. The derived metric recovers the standard solutions’ limits. It tends to the commutative case solution found in [P. G. S. Fernandes, Phys. Lett. B 805, 135468 (2020)] at large distance $\frac{r_{+}}{\sqrt{\theta }}\to \infty$ and the general relativity solution with smeared mass and charge as $\alpha \to 0$. The charged solution obtained is singular at the origin in contrast to its neutral version, which is regular. The thermodynamic quantities have been modified due to the influence of noncommutativity. The heat capacity was used to investigate the local thermal stability. The black hole has been discovered to be locally stable for small and large radii, but unstable for middle radii.

In this paper, we study the associated production of prompt $J/\psi$ mesons and $Z(W)$ bosons in the improved color evaporation model using the high-energy factorization as it is formulated in the parton Reggeization approach. The last one is based on the modified Kimber–Martin–Ryskin–Watt model for unintegrated parton distribution functions and the effective field theory of Reggeized gluons and quarks, suggested by Lipatov. We predict cross-section for associated $J/\psi$ and $Z(W)$ hadroproduction via the single and double parton scattering mechanisms using the set of model parameters which has been obtained early for description of single and double prompt $J/\psi$ production at the LHC energies. The numerical calculations are realized using the Monte Carlo event generator KaTie. The calculation results are compared with the data at the energies $\sqrt{s}=7$TeV and 8TeV and we make predictions for the energy $\sqrt{s}=13$TeV for $J/\psi$ plus $Z(W)$ and $\mathrm{\Upsilon }$ plus $Z(W)$ associated production at $\sqrt{s}=8$TeV and 13TeV.

In this work, we consider two modified Chevallier–Polarski–Linder (CPL) models in the background of homogeneous and isotropic Friedmann–Lemaître–Robertson–Walker (FLRW) space–time, namely, (i) the generalized CPL model (Model I) and (ii) the logarithmic form of the equation of state for the dark energy. From the observational data sets $((\text{Pantheon}+)+\text{BAO}+\text{HST})$, we find that at the present epoch (redshift $z=0$), the equation of state for the dark energy converges almost at the same value ${\omega }_{\mathrm{\text{fld}}}\approx -0.86$ and the variation of ${\omega }_{\mathrm{\text{fld}}}(z)$ with respect to the redshift parameter is very small for both models. We also find that the present value of the Hubble parameter $H_0$ is almost same for both the models. Finally, we compare the models in the light of Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC) and Bayesian evidence. However, we find that Model II is better compared to Model I from the estimated value of the deceleration parameter.