The European Physical Journal C

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

List of Papers (Total 3,248)

Spherical conformal models for compact stars

We consider spherical exact models for compact stars with anisotropic pressures and a conformal symmetry. The conformal symmetry condition generates an integral relationship between the gravitational potentials. We solve this condition to find a new anisotropic solution to the Einstein field equations. We demonstrate that the exact solution produces a relativistic model of a ...

Correction to: Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector

Unfortunately, in the original version of this article the copyright holder was wrong in the HTML. The original article has been corrected.

Influence of external magnetic field, finite-size effects and chemical potential on the phase transition of a complex scalar field

A scalar model is built, as a quantum field theory defined on a toroidal topology, to describe a phase transition in films subjected to periodic boundary conditions and influenced by an external and constant magnetic field. Criticality is studied and the relations between the critical temperature, the film thickness, the magnetic field strength and the chemical potential are ...

Corrections for a constant radial magnetic field in the muon \({{\varvec{g}}}\) –2 and electric-dipole-moment experiments in storage rings

We calculate the corrections for constant radial magnetic field in muon \({g}-2\) and electric-dipole-moment experiments in storage rings. While the correction is negligible for the current generation of \({g}-2\) experiments, it affects the upcoming muon electric-dipole-moment experiment at Fermilab.

Impact of generalized dissipative coefficient on warm inflationary dynamics in the light of latest Planck data

The warm inflation scenario in view of the modified Chaplygin gas is studied. We consider the inflationary expansion to be driven by a standard scalar field whose decay ratio \(\Gamma \) has a generic power-law dependence with the scalar field \(\phi \) and the temperature of the thermal bath T. By assuming an exponential power-law dependence in the cosmic time for the scale factor ...

Evolution of compact stars and dark dynamical variables

This work aims to explore the dark dynamical effects of the f(R, T) modified gravity theory on the dynamics of a compact celestial star. We have taken the interior geometry of a spherical star which is filled with an imperfect fluid distribution. The modified field equations are explored by taking a particular form of the f(R, T) model, i.e. \(f(R,T)=f_1(R)+f_2(R)f_3(T)\). These ...

Measurement of the \(\nu _{\mu }\) energy spectrum with IceCube-79

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The \(\nu _\mu \) energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine ...

Classification of non-Riemannian doubled-yet-gauged spacetime

Assuming \(\mathbf {O}(D,D)\) covariant fields as the ‘fundamental’ variables, double field theory can accommodate novel geometries where a Riemannian metric cannot be defined, even locally. Here we present a complete classification of such non-Riemannian spacetimes in terms of two non-negative integers, \((n,\bar{n})\), \(0\le n+\bar{n}\le D\). Upon these backgrounds, strings ...

On flavourful Easter eggs for New Physics hunger and lepton flavour universality violation

Within the standard approach of effective field theory of weak interactions for \(\varDelta B = 1\) transitions, we look for possibly unexpected subtle New Physics effects, here dubbed “flavourful Easter eggs”. We perform a Bayesian global fit using the publicly available HEPfit package, taking into account state-of-the-art experimental information concerning these processes, ...

Dynamics of coupled phantom and tachyon fields

In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exists a late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the ...

Knotty inflation and the dimensionality of spacetime

We suggest a structure for the vacuum comprised of a network of tightly knotted/linked flux tubes formed in a QCD-like cosmological phase transition and show that such a network can drive cosmological inflation. As the network can be topologically stable only in three space dimensions, this scenario provides a dynamical explanation for the existence of exactly three large spatial ...

Relativistic corrections to the static energy in terms of Wilson loops at weak coupling

We consider the \({\mathcal {O}}(1/m)\) and the spin-independent momentum-dependent \({\mathcal {O}}(1/m^2)\) quasi-static energies of heavy quarkonium (with unequal masses). They are defined nonperturbatively in terms of Wilson loops. We determine their short-distance behavior through \(\mathcal{O}(\alpha ^3)\) and \(\mathcal{O}(\alpha ^2)\), respectively. In particular, we ...

On the compatibility of the IceCube results with a universal neutrino spectrum

There is mounting evidence that the IceCube findings cannot be described simply invoking a single power-law spectrum for cosmic neutrinos. We discuss which the minimal modifications are of the spectrum that are required by the existing observations and we obtain a universal cosmic neutrino spectrum, i.e. valid for all neutrino flavors. Our approach to such task can be outlined in ...

Exorcising ghosts in induced gravity

Unitarity of the scale-invariant coupled theory of higher-derivative gravity and matter is investigated. A scalar field coupled with a Dirac fermion is taken as the matter sector. Following the idea of induced gravity the Einstein–Hilbert term is generated via dynamical symmetry breaking of scale invariance. The renormalisation group flows are computed and one-loop RG improved ...

Testing and selecting cosmological models with ultra-compact radio quasars

In this paper, we place constraints on four alternative cosmological models under the assumption of the spatial flatness of the Universe: CPL, EDE, GCG and MPC. A new compilation of 120 compact radio quasars observed by very-long-baseline interferometry, which represents a type of new cosmological standard rulers, are used to test these cosmological models. Our results show that ...

Improved limit on the branching fraction of the rare decay \({{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-\)

A search for the decay \({{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-\) is performed, based on a data sample of proton-proton collisions corresponding to an integrated luminosity of \(3\,\text{ fb }^{-1} \), collected by the LHCb experiment at centre-of-mass energies of 7 and 8\(\mathrm {\,TeV}\). The observed yield is consistent with the background-only ...

Dynamical analysis for a scalar–tensor model with Gauss–Bonnet and non-minimal couplings

We study the autonomous system for a scalar–tensor model of dark energy with Gauss–Bonnet and non-minimal couplings. The critical points describe important stable asymptotic scenarios including quintessence, phantom and de Sitter attractor solutions. Two functional forms for the coupling functions and the scalar potential are considered: power-law and exponential functions of the ...

Existence of stable wormholes on a non-commutative-geometric background in modified gravity

In this paper, we discuss spherically symmetric wormhole solutions in f(R, T) modified theory of gravity by introducing well-known non-commutative geometry in terms of Gaussian and Lorentzian distributions of string theory. For analytic discussion, we consider an interesting model of f(R, T) gravity defined by \(f(R,T)=f_{1}(R)+\lambda T\). By taking two different choices for the ...

Measurements of \(\pi ^\pm \) , K \(^\pm \) , p and \({\bar{\text {p}}}\) spectra in proton-proton interactions at 20, 31, 40, 80 and 158 \(\text{ GeV }/c\) with the NA61/SHINE spectrometer at the CERN SPS

Measurements of inclusive spectra and mean multiplicities of \(\pi ^\pm \), K\(^\pm \), p and \({\bar{\text {p}}}\) produced in inelastic p + p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 \(\text{ GeV }/c\) (\(\sqrt{s} = \) 6.3, 7.7, 8.8, 12.3 and 17.3 \(\text{ GeV }\), respectively) were performed at the CERN Super Proton Synchrotron using the large ...

Performance of the ATLAS track reconstruction algorithms in dense environments in LHC Run 2

With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13 \(\text {TeV}\) for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking ...

Inflationary scenario from higher curvature warped spacetime

We consider a five dimensional warped spacetime, in presence of the higher curvature term like \(F(R) = R + \alpha R^2\) in the bulk, in the context of the two-brane model. Our universe is identified with the TeV scale brane and emerges as a four dimensional effective theory. From the perspective of this effective theory, we examine the possibility of “inflationary scenario” by ...

Emerging anisotropic compact stars in \(f(\mathcal {G},T)\) gravity

The possible emergence of compact stars has been investigated in the recently introduced modified Gauss–Bonnet \(f(\mathcal {G},T)\) gravity, where \(\mathcal {G}\) is the Gauss–Bonnet term and T is the trace of the energy-momentum tensor (Sharif and Ikram, Eur Phys J C 76:640, 2016). Specifically, for this modified \(f(\mathcal {G}, T)\) theory, the analytic solutions of Krori and ...

Examining a renormalizable supersymmetric SO(10) model

We examine a renormalizable SUSY SO(10) model without fine-tuning. We show how to construct MSSM doublets and to predict proton decay. We find that in the minimal set of Yukawa couplings the model is consistent with the experiments, while including \(120_H\) to fit the data there are inconsistencies.

New construction of quantum error-avoiding codes via group representation of quantum stabilizer codes

In quantum computing, nice error bases as generalization of the Pauli basis were introduced by Knill. These bases are known to be projective representations of finite groups. In this paper, we propose a group representation approach to the study of quantum stabilizer codes. We utilize this approach to define decoherence-free subspaces (DFSs). Unlike previous studies of DFSs, this ...

Masses of scalar and axial-vector B mesons revisited

The SU(3) quark model encounters a great challenge in describing even-parity mesons. Specifically, the \(q\bar{q}\) quark model has difficulties in understanding the light scalar mesons below 1 GeV, scalar and axial-vector charmed mesons and \(1^+\) charmonium-like state X(3872). A common wisdom for the resolution of these difficulties lies on the coupled channel effects which will ...