A bounce universe model, known as the coupled-scalar-tachyon bounce (CSTB) universe, has been shown to solve the Horizon, Flatness and Homogeneity problems as well as the Big Bang singularity problem. Furthermore a scale invariant spectrum of primordial density perturbations generated from the phase of pre-bounce contraction is shown to be stable against time evolution. In this...

Among the various possibilities to probe the theory behind the recent accelerated expansion of the universe, the energy conditions (ECs) are of particular interest, since it is possible to confront and constrain different theories of gravity with observational data. In this context, we use the ECs to probe any alternative theory of gravity whose extra term acts as a cosmological...

The freeze-out of massless particles is investigated. The effects due to quantum statistics, Fermi-Dirac or Bose-Einstein, of all particles relevant for the process are analyzed. Solutions of appropriate Boltzmann equation are compared with those obtained using some popular approximate methods. As an application of general results the relic density of dark radiation in Weinberg’s...

In this research, we consider thermodynamically the behaviour of an accelerating BIon and show that the entropy of this system has the form of Tsallis entropy. A BIon is a system that consists of a brane, an anti-brane and a wormhole which connects them together. By increasing the acceleration of branes, the area of BIon increases and its Tsallis entropy grows.

We explore the response of the momentum dissipation introduced by spatial linear axionic fields in a holographic model without self-duality, which is broke by Weyl tensor coupling to Maxwell field. It is found that for the positive Weyl coupling parameter \(\gamma >0\), the momentum dissipation, characterized by parameter \({\hat{\alpha }}\), drives an incoherent metallic state...

In their recent work (Eiroa and Aguirre in Eur Phys J C 76:132, 2016), Eiroa and Aguirre introduced thin-shell wormholes in \(F\left( R\right) =R+\alpha R^{2}\)-gravity coupled with the Maxwell electromagnetic field. Here in this note we shall address an interesting feature of their results which has been missed. It will be shown that thin-shell wormhole can not be formed in the...

We perform a non-perturbative study of the scale-dependent renormalisation factors of a complete set of dimension-six four-fermion operators without power subtractions. The renormalisation-group (RG) running is determined in the continuum limit for a specific Schrödinger Functional (SF) renormalisation scheme in the framework of lattice QCD with two dynamical flavours (\(N_...

Direct Dark Matter searches are nowadays one of the most fervid research topics with many experimental efforts devoted to the search for nuclear recoils induced by the scattering of Weakly Interactive Massive Particles (WIMPs). Detectors able to reconstruct the direction of the nucleus recoiling against the scattering WIMP are opening a new frontier to possibly extend Dark Matter...

We consider the black hole information problem within the context of collapse theories in a scheme that allows the incorporation of the backreaction to the Hawking radiation. We explore the issue in a setting of the two dimensional version of black hole evaporation known as the Russo-Susskind-Thorlacius model. We summarize the general ideas based on the semiclassical version of...

Quasilocal formulations of black hole are of immense importance since they reveal the essential and minimal assumptions required for a consistent description of black hole horizon, without relying on the asymptotic boundary conditions on fields. Using the quasilocal formulation of Isolated Horizons, we construct the Hamiltonian charges corresponding to local Lorentz...

For a pair of incompatible quantum measurements, the total uncertainty can be bounded by a state-independent constant. However, such a bound can be violated if the quantum system is entangled with another quantum system (called memory); the quantum correlation between the systems can reduce the measurement uncertainty. On the other hand, in a curved spacetime, the presence of the...

Using AdS/CFT correspondence, we investigate the effect of a constant magnetic field on the jet quenching parameter in strongly-coupled \({{\mathcal {N}}}=4\) SYM plasma. We analyze the jet moving parallel and transverse to the magnetic field, respectively. For both cases, it is found that the jet quenching parameter is generally enhanced in the presence of a magnetic field...

We apply the Wald formalism to obtain masses and angular momenta of black holes in three dimensional gravity theories using the first order formalism. Wald formalism suggests that the entropy of a black hole can be defined by an integration of a conserved charge on the bifurcation horizon, and mass and angular momentum of a black hole as an integration of some charge variation...

We construct a general stratified scalar theory of gravitation from a field equation that accounts for the self-interaction of the field and a particle Lagrangian, and calculate its post-Newtonian parameters. Using this general framework, we analyze several specific scalar theories of gravitation and check their predictions for the solar system post-Newtonian effects.

In this paper, we investigate the behavior of a scalar particle within the Yukawa-like potential in a Gödel-type space-time for any l. The behavior of a spinless particle is analyzed in the presence of a topological defect with analytical solutions to the Klein–Gordon equation. By using the generalized series and Nikiforov-Uvarof (NU) methods, we deduce the energy eigenvalues and...

In this article, we construct the \(C \otimes \gamma _\mu C\) and \(C\gamma _5 \otimes \gamma _5\gamma _\mu C\) type currents to interpolate the vector tetraquark states, then carry out the operator product expansion up to the vacuum condensates of dimension-10 in a consistent way, and obtain four QCD sum rules. In calculations, we use the formula \(\mu =\sqrt{M^2_{Y}-(2{\mathbb...

The nuclear modification factors of \({\mathrm {J}/\psi }\) and \(\psi \text {(2S)}\) mesons are measured in \(\text {PbPb}\) collisions at a centre-of-mass energy per nucleon pair of \(\sqrt{\smash [b]{s_{_{\text {NN}}}}} = 5.02\,\text {Te}\text {V} \). The analysis is based on \(\text {PbPb}\) and \(\mathrm {p}\mathrm {p}\) data samples collected by CMS at the LHC in 2015...

The \(\mu \nu \mathrm {SSM}\) is a simple supersymmetric extension of the Standard Model (SM) capable of predicting neutrino physics in agreement with experiment. In this paper we perform the complete one-loop renormalization of the neutral scalar sector of the \(\mu \nu \mathrm {SSM}\) with one generation of right-handed neutrinos in a mixed on-shell/\({\overline{\mathrm {DR...

We present a comparison of the computation of energy–energy correlation in \(e^{+}e^{-}\) collisions in the back-to-back region at next-to-next-to-leading logarithmic accuracy matched with the next-to-next-to-leading order perturbative prediction to LEP, PEP, PETRA, SLC and TRISTAN data. With these predictions we perform an extraction of the strong coupling constant taking into...

In the high energy limit of scattering amplitudes in Quantum Chromodynamics and supersymmetric theories the dominant Feynman diagrams are characterized by a hidden integrability in the planar limit. A well-known example is that of Odderon exchange, which can be described as a composite state of three reggeized gluons and corresponds to a closed spin chain with periodic boundary...

We point out a misleading treatment in a recent paper published in this Journal (Sobhani et al., Eur Phys J C 78:106, 2018) regarding solutions for the Schrödinger equation with a anharmonic oscillator potential embedded in the background of a cosmic string mapped into biconfluent Heun equation. This fact jeopardizes the thermodynamical properties calculated in this system.

In this paper, the b quark pair production events are analyzed as a source of neutral Higgs bosons of the two Higgs doublet model type I at linear colliders. The production mechanism is \(e^{+}e^{-} \rightarrow Z^{(*)} \rightarrow HA \rightarrow b{\bar{b}}b{\bar{b}}\) assuming a fully hadronic final state. The analysis aim is to identify both CP-even and CP-odd Higgs bosons in...

We study generic effects of new physics on the rare decay modes \(K_L \rightarrow \pi ^0 \nu {\bar{\nu }}\) and \(K^+ \rightarrow \pi ^+ \nu {\bar{\nu }}\). We discuss several cases: left-handed neutrino couplings; right handed neutrino couplings; neutrino lepton flavour violating (LFV) interactions; and \(\Delta I =3/2\) interactions. The first of these cases has been studied...

The strong direct detection limits could be pointing to dark matter – nucleus scattering at loop level. We study in detail the prototype example of an electroweak singlet (Dirac or Majorana) dark matter fermion coupled to an extended dark sector, which is composed of a new fermion and a new scalar. Given the strong limits on colored particles from direct and indirect searches we...

In the present paper, we investigate the dark energy equation of state using the Gaussian processes analysis method, without confining a particular parametrization. The reconstruction is carried out by adopting the background data including supernova and Hubble parameter, and perturbation data from the growth rate. It suggests that the background and perturbation data both...