The European Physical Journal C

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

List of Papers (Total 2,952)

Higgs pair production in vector-boson fusion at the LHC and beyond

The production of pairs of Higgs bosons at hadron colliders provides unique information on the Higgs sector and on the mechanism underlying electroweak symmetry breaking (EWSB). Most studies have concentrated on the gluon-fusion production mode which has the largest cross section. However, despite its small production rate, the vector-boson fusion channel can also be relevant since ...

Collision of two rotating Hayward black holes

We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effect in the near-horizon region affects the interaction and the ...

Quantitative theory of channeling particle diffusion in transverse energy in the presence of nuclear scattering and direct evaluation of dechanneling length

A refined equation for channeling particle diffusion in transverse energy taking into consideration large-angle scattering by nuclei is suggested. This equation is reduced to the Sturm–Liouville problem, allowing one to reveal both the origin and the limitations of the dechanneling length notion. The values of the latter are evaluated for both positively and negatively charged ...

Bianchi I cosmology in the presence of a causally regularized viscous fluid

We analyze the dynamics of a Bianchi I cosmology in the presence of a viscous fluid, causally regularized according to the Lichnerowicz approach. We show how the effect induced by shear viscosity is still able to produce a matter creation phenomenon, meaning that also in the regularized theory we address, the Universe is emerging from a singularity with a vanishing energy density ...

Phase transition and gravitational wave phenomenology of scalar conformal extensions of the Standard Model

Thermal corrections in classically conformal models typically induce a strong first-order electroweak phase transition, thereby resulting in a stochastic gravitational background that could be detectable at gravitational wave observatories. After reviewing the basics of classically conformal scenarios, in this paper we investigate the phase transition dynamics in a thermal ...

Rest frames and relativistic effects on de Sitter spacetimes

It is shown that the Nachtmann boosting method of introducing coordinates on de Sitter manifolds can be completed with suitable gauge transformations able to keep under control the transformation under isometries of the conserved quantities. With this method, the rest local charts (or natural frames) are defined pointing out the role of the conserved quantities in investigating the ...

Vector boson production in pPb and PbPb collisions at the LHC and its impact on nCTEQ15 PDFs

We provide a comprehensive comparison of \(W^\pm / Z\) vector boson production data in pPb and PbPb collisions at the LHC with predictions obtained using the nCTEQ15 PDFs. We identify the measurements which have the largest potential impact on the PDFs, and estimate the effect of including these data using a Bayesian reweighting method. We find this data set can provide information ...

Dispersion relations for \(\eta '\rightarrow \eta \pi \pi \)

We present a dispersive analysis of the decay amplitude for \(\eta '\rightarrow \eta \pi \pi \) that is based on the fundamental principles of analyticity and unitarity. In this framework, final-state interactions are fully taken into account. Our dispersive representation relies only on input for the \({\pi \pi }\) and \({\pi }\eta \) scattering phase shifts. Isospin symmetry ...

On the spinor representation

A systematic study of the spinor representation by means of the fermionic physical space is accomplished and implemented. The spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the spinor bilinear covariants. A robust geometric and topological structure can be manifested from the spinor space, wherein the first and second homotopy ...

Jet reconstruction and performance using particle flow with the ATLAS Detector

This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb\(^{-1}\) of ATLAS data from 8 TeV proton–proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker. This improves ...

Coupled fermion–kink system in Jackiw–Rebbi model

In this paper, we study Jackiw–Rebbi model, in which a massless fermion is coupled to the kink of \(\lambda \phi ^4\) theory through a Yukawa interaction. In the original Jackiw–Rebbi model, the soliton is prescribed. However, we are interested in the back-reaction of the fermion on the soliton besides the effect of the soliton on the fermion. Also, as a particular example, we ...

Exceptional composite dark matter

We study the dark matter phenomenology of non-minimal composite Higgs models with SO(7) broken to the exceptional group \(G_2\). In addition to the Higgs, three pseudo-Nambu–Goldstone bosons arise, one of which is electrically neutral. A parity symmetry is enough to ensure this resonance is stable. In fact, if the breaking of the Goldstone symmetry is driven by the fermion sector, ...

Controlling the sign problem in finite-density quantum field theory

Quantum field theories at finite matter densities generically possess a partition function that is exponentially suppressed with the volume compared to that of the phase quenched analog. The smallness arises from an almost uniform distribution for the phase of the fermion determinant. Large cancellations upon integration is the origin of a poor signal to noise ratio. We study three ...

Measurement of the jet mass in highly boosted \({\mathrm{t}}\overline{\mathrm{t}}\) events from pp collisions at \(\sqrt{s}=8\) \(\,\text {TeV}\)

The first measurement of the jet mass \(m_{\text {jet}}\) of top quark jets produced in \({\mathrm{t}}\overline{\mathrm{t}} \) events from pp collisions at \(\sqrt{s}=8\) \(\,\text {TeV}\) is reported for the jet with the largest transverse momentum \(p_{\mathrm{T}}\) in highly boosted hadronic top quark decays. The data sample, collected with the CMS detector, corresponds to an ...

To \({d}\) , or not to \({d}\) : recent developments and comparisons of regularization schemes

We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them.

COSMOS- \(e'\) -soft Higgsotic attractors

In this work, we have developed an elegant algorithm to study the cosmological consequences from a huge class of quantum field theories (i.e. superstring theory, supergravity, extra dimensional theory, modified gravity, etc.), which are equivalently described by soft attractors in the effective field theory framework. In this description we have restricted our analysis for two ...

Generalized second law of thermodynamic in modified teleparallel theory

This study is conducted to examine the validity of the generalized second law of thermodynamics (GSLT) in flat FRW for modified teleparallel gravity involving coupling between a scalar field with the torsion scalar T and the boundary term \(B=2\nabla _{\mu }T^{\mu }\). This theory is very useful, since it can reproduce other important well-known scalar field theories in suitable ...

Ambitwistor superstring in the Green–Schwarz formulation

In this paper we construct the ambitwistor superstring in the Green–Schwarz formulation. The model is obtained from the related pure spinor version. We show that the spectrum contains only ten-dimensional supergravity and that kappa symmetry in a curved background implies some of the standard constraints.

Observational properties of rigidly rotating dust configurations

We study the observational properties of a class of exact solutions of Einstein’s field equations describing stationary, axially symmetric, rigidly rotating dust (i.e. non-interacting particles). We ask the question whether such solutions can describe astrophysical rotating dark matter clouds near the center of galaxies and we probe the possibility that they may constitute an ...

A chiral covariant approach to \(\varvec{\rho \rho }\) scattering

We analyze vector meson–vector meson scattering in a unitarized chiral theory based on a chiral covariant framework restricted to \(\rho \rho \) intermediate states. We show that a pole assigned to the scalar meson \(f_0(1370)\) can be dynamically generated from the \(\rho \rho \) interaction, while this is not the case for the tensor meson \(f_2(1270)\) as found in earlier work. ...

Anisotropic SD2 brane: accelerating cosmology and Kasner-like space-time from compactification

Starting from an anisotropic (in all directions including the time direction of the brane) non-SUSY D2 brane solution of type IIA string theory we construct an anisotropic space-like D2 brane (or SD2 brane, for short) solution by the standard trick of a double Wick rotation. This solution is characterized by five independent parameters. We show that compactification on ...

Warm inflation with an oscillatory inflaton in the non-minimal kinetic coupling model

In the cold inflation scenario, the slow roll inflation and reheating via coherent rapid oscillation, are usually considered as two distinct eras. When the slow roll ends, a rapid oscillation phase begins and the inflaton decays to relativistic particles reheating the Universe. In another model dubbed warm inflation, the rapid oscillation phase is suppressed, and we are left with ...

The K-meson form factor and charge radius: linking low-energy data to future Jefferson Laboratory measurements

Starting from a successful model of the \(\pi \)-meson electromagnetic form factor, we calculate a similar form factor, \(F_{K}(Q^{2})\), of the charged K meson for a wide range of the momentum transfer squared, \(Q^{2}\). The only remaining free parameter is to be determined from the measurements of the K-meson charge radius, \(r_{K}\). We fit this single parameter to the ...

Integrability from point symmetries in a family of cosmological Horndeski Lagrangians

For a family of Horndeski theories, formulated in terms of a generalized Galileon model, we study the integrability of the field equations in a Friedmann–Lemaître–Robertson–Walker space-time. We are interested in point transformations which leave invariant the field equations. Noether’s theorem is applied to determine the conservation laws for a family of models that belong to the ...

Measurement of double-differential cross sections for top quark pair production in pp collisions at \(\sqrt{s} = 8\) \(\,\text {TeV}\) and impact on parton distribution functions

Normalized double-differential cross sections for top quark pair (\(\mathrm{t}\overline{\mathrm{t}}\)) production are measured in pp collisions at a centre-of-mass energy of 8\(\,\text {TeV}\) with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 19.7\(\,\text {fb}^{-1}\). The measurement is performed in the dilepton \(\mathrm {e}^{\pm }\mu ...