The European Physical Journal C

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

List of Papers (Total 9,882)

Nilpotent superfields for broken abelian symmetries

We find new solutions to real cubic constraints on $$N=1$$ chiral superfields transforming under global abelian symmetries. These solutions describe the low-energy dynamics of a goldstino interacting with an axion (both belonging to the same chiral superfield) with non-linearly realized supersymmetry. We show the relation between our model and the approach of Komargodski and...

Renormalization of the topological charge density in QCD with dimensional regularization

To all orders of perturbation theory, the renormalization of the topological charge density in dimensionally regularized QCD is shown to require no more than an additive renormalization proportional to the divergence of the flavour-singlet axial current. The proof is based on the standard BRS analysis of the QCD vertex functional in the background gauge and exploits the special...

Probing UHECR production in Centaurus A using secondary neutrinos and gamma-rays

In this paper the production of neutrinos and photons by ultra high energy cosmic rays (UHECR) interacting with the extragalactic background radiation is studied. Centaurus A is assumed as the prime source of UHECR and the possibility to identify this source by detecting the secondary neutrinos and photons produced in the propagation of UHECR is investigated. Fifteen...

Lotty – The loop-tree duality automation

Elaborating on the novel formulation of the loop-tree duality, we introduce the Mathematica package Lotty that automates the latter at multi-loop level. By studying the features of Lotty and recalling former studies, we discuss that the representation of any multi-loop amplitude can be brought in a form, at integrand level, that only displays physical information, which we refer...

Orbifold black holes

We construct a regular black hole solution on the orbifold $${\mathbb C}^{n}/{\mathbb Z}_{n}$$ in the ( $$2n+1$$ )-dimensional Einstein–Maxwell theory. The event horizon is $$S^{2n-1}/{\mathbb Z}_{n}$$ .

On the choice of the collapse operator in cosmological Continuous Spontaneous Localisation (CSL) theories

The Continuous Spontaneous Localisation (CSL) theory in the cosmological context is subject to uncertainties related to the choice of the collapse operator. In this paper, we constrain its form based on generic arguments. We show that, if the collapse operator is even in the field variables, it is unable to induce the collapse of the wavefunction. Instead, if it is odd, we find...

The hubble tension as a hint of leptogenesis and neutrino mass generation

The majoron, a neutrinophilic pseudo-Goldstone boson conventionally arising in the context of neutrino mass models, can damp neutrino free-streaming and inject additional energy density into neutrinos prior to recombination. The combination of these effects for an eV-scale mass majoron has been shown to ameliorate the outstanding $$H_0$$ tension, however only if one introduces...

The design of the n2EDM experiment

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver...

Light neutrino masses from gravitational condensation: the Schwinger–Dyson approach

In this work we demonstrate that non-zero neutrino masses can be generated from gravitational interactions. We solve the Schwinger–Dyson equations to find a non-trivial vacuum thereby determining the neutrino condensate scale and the number of new particle degrees of freedom required for gravitationally induced dynamical chiral symmetry breaking. We show for minimal beyond the...

Gauging scale symmetry and inflation: Weyl versus Palatini gravity

We present a comparative study of inflation in two theories of quadratic gravity with gauged scale symmetry: (1) the original Weyl quadratic gravity and (2) the theory defined by a similar action but in the Palatini approach obtained by replacing the Weyl connection by its Palatini counterpart. These theories have different vectorial non-metricity induced by the gauge field...

Effect of gravitational wave on shadow of a Schwarzschild black hole

We have studied the shadows of a Schwarzschild black hole under a special polar gravitational perturbation, which is a particular solution of Einstein equations expanded up to first order. It is shown that the black hole shadow changes periodically with time and the change of shadow depends on the Legendre polynomial order parameter l and the frequency $$\sigma $$ of...

Deflection of light by a Coulomb charge in Born–Infeld electrodynamics

We study the propagation of light under a strong electric field in Born–Infeld electrodynamics. The nonlinear effect can be described by the effective indices of refraction. Because the effective indices of refraction depend on the background electric field, the path of light can be bent when the background field is non-uniform. We compute the bending angle of light by a Born...

Massless fermions in planar Bianchi-type-I universes: exact and approximate solutions

Based upon the exact formal solutions of the Weyl–Dirac-equation in anisotropic planar Bianchi-type-I background spacetimes with power law scale factors, one can introduce suitable equivalence classes of the solutions of these models. The associated background spacetimes are characterized by two parameters. It is shown that the exact solutions of all models of a given equivalence...

xPPN: an implementation of the parametrized post-Newtonian formalism using xAct for Mathematica

We present a package for the computer algebra system Mathematica, which implements the parametrized post-Newtonian (PPN) formalism. This package, named xPPN, is built upon the widely used tensor algebra package suite xAct, and in particular the package xTensor therein. The main feature of xPPN is to provide functions to perform a proper $$3+1$$ decomposition of tensors, as well...

Baryogenesis, magnetogenesis and the strength of anomalous interactions

The production of the hypermagnetic gyrotropy is investigated under the assumption that the gauge coupling smoothly evolves during a quasi-de Sitter phase and then flattens out in the radiation epoch by always remaining perturbative. In the plane defined by the strength of the anomalous interactions and by the rate of evolution of the gauge coupling the actual weight of the...

Greybody radiation and quasinormal modes of Kerr-like black hole in Bumblebee gravity model

In the framework of the Lorentz symmetry breaking (LSB), we investigate the quasinormal modes (QNMs) and the greybody factors (GFs) of the Kerr-like black hole spacetime obtained from the bumblebee gravity model. In particular, we analyze the scalar and fermionic perturbations of the black hole within the framework of both semi-analytic WKB method and the time domain approach...

The hadronic $$\tau $$ τ decay $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau $$ τ - → K 1 - ν τ → ( K - ω ) ν τ → ( K - π + π - π 0 ) ν τ and the axial vector mixing angle

We propose to measure the $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau \ $$ decay in order to determine the $$K_1$$ axial vector mixing angle $$\theta _{K_1}$$ . We derive, for the first time, the differential decay rate formula for this decay mode. Using the obtained result, we perform a sensitivity study...

Characterization of inverted coaxial $$^{76}$$ 76 Ge detectors in GERDA for future double- $$\beta $$ β decay experiments

Neutrinoless double- $$\beta $$ decay of $$^{76}$$ Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material...

Topological preons from algebraic spinors

It is demonstrated that many of the assumed rules that govern the structure of a previously proposed topological preon model, in which simple non-trivial braids consisting of three twisted ribbons are mapped to the first generation of leptons and quarks, are automatically adhered to when the algebraic spinors of two complex Clifford algebras are identified with braids via a...

The generation of matter–antimatter asymmetries and hypermagnetic fields by the chiral vortical effect of transient fluctuations

We study the contribution of the temperature-dependent chiral vortical effect to the generation and evolution of hypermagnetic fields and matter-antimatter asymmetries, in the symmetric phase of the early Universe, in the temperature range 100 GeV $$\le T \le $$ 10 TeV. Our most important result is that, due to the chiral vortical effect, small overlapping transient fluctuations...

Adiabatic analysis of the rotating BTZ black hole

In this paper we analyze some interesting features of the thermodynamics of the rotating BTZ black hole from the Carathéodory axiomatic postulate, for which, we exploit the appropriate Pfaffian form. The allowed adiabatic transformations are then obtained by solving the corresponding Cauchy problem, and are studied accordingly. Furthermore, we discuss the implications of our...

Expectation management

We consider the application of a Fleischer–Jegerlehner-like treatment of tadpoles to the calculation of neutral scalar masses (including the Higgs) in general theories beyond the Standard Model. This is especially useful when the theory contains new scalars associated with a small expectation value, but comes with its own disadvantages. We show that these can be overcome by...

Curing the unphysical behaviour of NLO quarkonium production at the LHC and its relevance to constrain the gluon PDF at low scales

We address the unphysical energy dependence of quarkonium-hadroproduction cross sections at Next-to-Leading Order (NLO) in $$\alpha _s$$ which we attribute to an over-subtraction in the factorisation of the collinear singularities inside the PDFs in the $$\overline{\text {MS}}$$ scheme. Such over- or under-subtractions have a limited phenomenological relevance in most of the...

Observational constraints in metric-affine gravity

We derive the main classical gravitational tests for a recently found vacuum solution with spin and dilation charges in the framework of Metric-Affine gauge theory of gravity. Using the results of the perihelion precession of the star S2 by the GRAVITY collaboration and the gravitational redshift of Sirius B white dwarf we constrain the corrections provided by the torsion and...