The European Physical Journal C

http://link.springer.com/journal/10052

List of Papers (Total 4,442)

U(1) extension of the standard model from short-distance structure of spacetime

In this paper, we presented a \(\mathrm {U}(1)\) extension of the SM and the corresponding consequences, based on a more fundamental structure of the spacetime. We started fundamentally from a generally covariant theory which includes a set of the fields propagating dynamically in the fundamental spacetime and respecting for the SM gauge group. We then derived, in the effective...

Measurements of inclusive and differential fiducial cross-sections of \(t\bar{t}\gamma \) production in leptonic final states at \(\sqrt{s}=13~\text {TeV}\) in ATLAS

Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 \(\text{ fb }^{-1}\), collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 \(\text {TeV}\). The measurements are performed in single...

Universality of BSW mechanism for spinning particles

Bañados et al. (BSW) found that Kerr black holes can act as particle accelerators with collisions at arbitrarily high center-of-mass energies. Recently, collisions of particles with spin around some rotating black holes have been discussed. In this paper, we study the BSW mechanism for spinning particles by using a metric ansatz which describes a general rotating black hole. We...

Enhancing the cosmic-ray mass sensitivity of air-shower arrays by combining radio and muon detectors

The muonic and electromagnetic components of air showers are sensitive to the mass of the primary cosmic particle. The sizes of the components can be measured with particle detectors on ground, and the electromagnetic component in addition indirectly via its radio emission in the atmosphere. The electromagnetic particles do not reach the ground for very inclined showers. On the...

Measurement of the \({\mathrm {t}\overline{\mathrm {t}}}\) production cross section, the top quark mass, and the strong coupling constant using dilepton events in pp collisions at \(\sqrt{s}=13\,\text {Te}\text {V} \)

A measurement of the top quark–antiquark pair production cross section \(\sigma _{\mathrm {t}\overline{\mathrm {t}}} \) in proton–proton collisions at a centre-of-mass energy of 13\(\,\text {Te}\text {V}\) is presented. The data correspond to an integrated luminosity of \(35.9{\,\text {fb}^{-1}} \), recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events...

Tachyon inflation in teleparallel gravity

We present a tachyonic field inflationary model in a teleparallel framework. We show that tachyonic coupled with the f(T) gravity model can describe the inflation era in which f(T) is an arbitrary function of torsion scalar T. For this purpose, dynamical behavior of the tachyonic field in different potentials is studied, it is shown that the tachyonic field with these potentials...

Electroweak phase transition, gravitational waves and dark matter in two scalar singlet extension of the standard model

In this paper, the electroweak phase transition, the gravitational waves and the dark matter issues are investigated in two scalar singlet extension of the standard model. The detectability of the gravitational wave signals are discussed by comparing the results with the sensitivity curves of \(\mathbf {eLISA}\), \(\mathbf {ALIA}\), \(\mathbf {DECIGO}\) and \(\mathbf {BBO...

UV self-completion of a theory of superfluid dark matter

We show that the model of superfluid dark matter developed in Refs. Khoury (Phys Rev D 91(2):024022,  https://doi.org/10.1103/PhysRevD.91.024022, arXiv:1409.0012 [hep-th], 2015), Berezhiani and Khoury (Phys Rev D 92:103510,  https://doi.org/10.1103/PhysRevD.92.103510, arXiv:1507.01019 [astro-ph.CO], 2015) and Berezhiani and Khoury (Phys Lett B 753:639,  https://doi.org/10.1016/j...

Cosmological dynamics of the general non-canonical scalar field models

We extend the investigation of cosmological dynamics of the general non-canonical scalar field models by dynamical system techniques for a broad class of potentials and coupling functions. In other words, we do not restrict the analysis to exponential or power-law potentials and coupling functions. This type of investigation helps in understanding the general properties of a...

Gauge coupling unification without supersymmetry

We investigate the prospects to achieve unification of the gauge couplings in models without supersymmetry. We restrict our discussion to SU(5), SO(10) and \(E_6\) models that mimic the structure of the Standard Model as much as possible (“conservative models”). One possible reason for the non-unification of the standard model gauge couplings are threshold corrections which are...

On sign-changeable interaction in FLRW cosmology

We investigate an interacting two-fluid model in a spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) Universe, when the energy transfer between these two dark components is produced by a factorizable nonlinear sign-changeable interaction depending linearly on the energy density and quadratically on the deceleration parameter. We solve the source equation and obtain the...

Electromagnetic dipole moments and time reversal violating interactions for high energy charged baryons in bent crystals at LHC

Spin precession of channelled particles in bent crystals at the LHC gives unique possibility for measurements of constants determining T-odd, P-odd (CP) violating interactions and P-odd, T-even interactions of charm, beauty and strange charged baryons with electrons and nucleus (nucleons), similarly to the possibility of measuring their electric and magnetic moments. For a...

Reduced Lagrangians and analytic solutions in Einstein-æther cosmology

We present the solution space of the field equations in the Einstein-æther theory for the case of a FLRW and a locally rotationally symmetric (LRS) Bianchi type III space-time. We also find that there are portions of the initial parameters space for which no solution is admitted by the reduced equations. The reduced Lagrangians deduced from the full action are, in general...

Unification of inflation and dark matter in the Higgs–Starobinsky model

In this work, we propose unified picture of inflation and dark matter in the Higgs–Starobinsky (HS) model. As pointed out in the literature, Starobinsky \(R^2\) inflation is induced by quantum correction effect from the large Higgs-curvature (graviton) coupling. We start with non-minimal coupling HS action in Jordan frame. We then transform the Jordan frame action into the...

Confining D-instanton background in an external electric field

Using holography, we discuss the effects of an external static electric field on the D3/D-instanton theory at zero-temperature, which is a quasi-confining theory, with confined quarks and deconfined gluons. We introduce the quarks to the theory by embedding a probe D7-brane in the gravity side, and turn on an appropriate U(1) gauge field on the flavor brane to describe the...

Phase transitions and geothermodynamics of black holes in dRGT massive gravity

In this paper, we study the thermodynamics and geothermodynamics of spherical black hole solutions in dRGT massive gravity in a new extended phase space. Inspire by the work of Kastor et al. (Class Quantum Gravity 26:195011, 2009), by interpreting the graviton mass as a thermodynamical variable, we propose a first law of thermodynamics which include a mass term and establish a...

Parallel adaptive Monte Carlo integration with the event generator WHIZARD

We describe a new parallel approach to the evaluation of phase space for Monte-Carlo event generation, implemented within the framework of the Whizard package. The program realizes a twofold self-adaptive multi-channel parameterization of phase space and makes use of the standard OpenMP and MPI protocols for parallelization. The modern MPI3 feature of asynchronous communication...

Analytic investigation of rotating holographic superconductors

In this paper we have investigated, in the probe limit, s-wave holographic superconductors in rotating \(AdS_{3+1}\) spacetime using the matching method as well as the Stürm–Liouville eigenvalue approach. We have calculated the critical temperature using the matching technique in such a setting and our results are in agreement with previously reported results obtained using the...

Dynamical evolution of non-minimally coupled scalar field in spherically symmetric de Sitter spacetimes

We investigate the dynamical behavior of a scalar field non-minimally coupled to Einstein’s tensor and Ricci scalar in geometries of asymptotically de Sitter spacetimes. We show that the quasinormal modes remain unaffected if the scalar field is massless and the black hole is electrically chargeless. In the massive case, the coupling of both parameters produces a region of...

Greybody factor for black string in dRGT massive gravity

The greybody factor from the black string in the de Rham–Gabadadze–Tolley (dRGT) massive gravity theory is investigated in this study. The dRGT massive gravity theory is one of the modified gravity theories used in explaining the current acceleration in the expansion of the universe. Through the use of cylindrical symmetry, black strings in dRGT massive gravity are shown to exist...

Thermodynamic analysis of modified teleparallel gravity involving higher-order torsion derivative terms

The present study is elaborated to investigate the validity of thermodynamical laws in a modified teleparallel gravity based on higher-order derivative terms of torsion scalar. For this purpose, we consider spatially flat FRW model filled with perfect fluid matter contents. Firstly, we explore the possibility of existence of equilibrium as well as non-equilibrium picture of...

Leading order CFT analysis of multi-scalar theories in \(d>2\)

We investigate multi-field multicritical scalar theories using CFT constraints on two- and three-point functions combined with the Schwinger–Dyson equation. This is done in general and without assuming any symmetry for the models, which we just define to admit a Landau–Ginzburg description that includes the most general critical interactions built from monomials of the form...

Clifford-based spectral action and renormalization group analysis of the gauge couplings

The Spectral Action Principle in noncommutative geometry derives the actions of the Standard Model and General Relativity (along with several other gravitational terms) by reconciling them in a geometric setting, and hence offers an explanation for their common origin. However, one of the requirements in the minimal formalism, unification of the gauge coupling constants, is not...

Stability and bifurcation analysis of interacting f(T) cosmology

The present work deals with dynamical system analysis of Interacting f(T) cosmology. Einstein field equations are second order non-linear differential equations. So it is very difficult to solve them analytically. We can draw the vector field and analyze the stability of the universe in different phase by dynamical system analysis. By suitable transformation of variables the...

Diffractive incoherent vector meson production off protons: a quark model approach to gluon fluctuation effects

Fluctuations play an important role in diffractive production of vector mesons. It was in particular recently suggested, based on the Impact-Parameter dependent Saturation model (IPSat), that geometrical fluctuations triggered by the motion of the constituent quarks within the protons could explain incoherent diffractive processes observed at HERA. We propose a variant of the...