The European Physical Journal C

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

List of Papers (Total 3,076)

Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected ...

GAMBIT: the global and modular beyond-the-standard-model inference tool

We describe the open-source global fitting package GAMBIT: the Global And Modular Beyond-the-Standard-Model Inference Tool. GAMBIT combines extensive calculations of observables and likelihoods in particle and astroparticle physics with a hierarchical model database, advanced tools for automatically building analyses of essentially any model, a flexible and powerful system for ...

Resonances in positron scattering on a supercritical nucleus and spontaneous production of \(e^{+}e^{-}\) pairs

We re-examine the physics of supercritical nuclei, specially focusing on the scattering phase \(\delta _{\varkappa }\) and its dependence on the energy \(\varepsilon \) of the diving electronic level, for which we give both exact and approximate formulas. The Coulomb potential \(Z\alpha /r\) is rounded to the constant \(Z\alpha /R\) for \(r < R\). We confirm the resonant behavior ...

Associated production of Z bosons and b-jets at the LHC in the combined \(k_T\) + collinear QCD factorization approach

We consider the production of Z bosons associated with beauty quarks at the LHC using a combined \(k_T\) + collinear QCD factorization approach, which interpolates between small x and large x physics. Our consideration is based on the off-shell gluon–gluon fusion subprocess \(g^* g^* \rightarrow Z Q\bar{Q}\) at the leading order \(\mathcal{O}(\alpha \alpha _s^2)\) (where the Z ...

Fermionic bound states in Minkowski space: light-cone singularities and structure

The Bethe–Salpeter equation for two-body bound system with spin 1/2 constituent is addressed directly in the Minkowski space. In order to accomplish this aim we use the Nakanishi integral representation of the Bethe–Salpeter amplitude and exploit the formal tool represented by the exact projection onto the null-plane. This formal step allows one (i) to deal with end-point ...

Scattering of decuplet baryons in chiral effective field theory

A formalism for treating the scattering of decuplet baryons in chiral effective field theory is developed. The minimal Lagrangian and potentials in leading-order SU(3) chiral effective field theory for the interactions of octet baryons (\(B\)) and decuplet baryons (\(D\)) for the transitions \(\mathrm{BB}\rightarrow \mathrm{BB}\), \(\mathrm{BB}\leftrightarrow \mathrm{DB}\), ...

Total spectral distributions from Hawking radiation

Taking into account the time dependence of the Hawking temperature and finite evaporation time of the black hole, the total spectral distributions of the radiant energy and of the number of particles have been explicitly calculated and compared to their temporary (initial) blackbody counterparts (spectral exitances).

On the generation of magnetostatic solutions from gravitational two-soliton solutions of a stationary mass

In the paper, magnetostatic solutions of the Einstein–Maxwell field equations are generated from the gravitational two-soliton solutions of a stationary mass. Using the soliton technique of Belinskii and Zakharov (Sov Phys JETP 48:985, 1978, Sov Phys JETP 50:1, 1979), we construct diagonal two-soliton solutions of Einstein’s gravitational field equations for an axially symmetric ...

Diphoton production in association with two bottom jets

We study the production of a photon pair in association with two bottom jets at the LHC. This process constitutes an important background to double Higgs production with the subsequent decay of the two Higgs bosons into a pair of photons and b-quarks respectively. We calculate this process at next-to-leading order accuracy in QCD and find that QCD corrections lead to a substantial ...

Measurements of the associated production of a Z boson and b jets in pp collisions at \({\sqrt{s}} = 8\,\text {TeV} \)

Measurements of the associated production of a \(\mathrm{Z}\) boson with at least one jet originating from a b quark in proton–proton collisions at \(\sqrt{s} = 8\,\text {TeV} \) are presented. Differential cross sections are measured with data collected by the CMS experiment corresponding to an integrated luminosity of 19.8\(\,\text {fb}^{-1}\). \(\mathrm{Z}\) bosons are ...

Photohadronic scenario in interpreting the February–March 2014 flare of 1ES 1011+496

The extraordinary multi-TeV flare from 1ES 1011+496 during February–March 2014 was observed by the MAGIC telescopes for 17 nights and the average spectrum of the whole period has a non-trivial shape. We have used the photohadronic model and a template extragalactic background light model to explain the average spectrum which fits the flare data well. The spectral index \(\alpha \) ...

Measurement of the triple-differential dijet cross section in proton-proton collisions at \(\sqrt{s}=8\,\text {TeV} \) and constraints on parton distribution functions

A measurement is presented of the triple-differential dijet cross section at a centre-of-mass energy of 8\(\,\text {TeV}\) using 19.7\(\,\text {fb}^\text {-1}\) of data collected with the CMS detector in proton-proton collisions at the LHC. The cross section is measured as a function of the average transverse momentum, half the rapidity separation, and the boost of the two leading ...

No-go for tree-level R-symmetry breaking

We show that in gauge mediation models with tree-level R-symmetry breaking where supersymmetry and R-symmetries are broken by different fields, the gaugino mass either vanishes at one loop or finds a contribution from loop-level R-symmetry breaking. Thus tree-level R-symmetry breaking for phenomenology is either no-go or redundant in the simplest type of models. Including explicit ...

Fate of an accretion disc around a black hole when both the viscosity and dark energy is in effect

This paper deals with the viscous accretion flow of a modified Chaplygin gas towards a black hole as the central gravitating object. A modified Chaplygin gas is a particular type of dark energy model which mimics of radiation era to phantom era depending on the different values of its parameters. We compare the dark energy accretion with the flow of adiabatic gas. An accretion disc ...

Late-time cosmological approach in mimetic f(R, T) gravity

In this paper, we investigate the late-time cosmic acceleration in mimetic f(R, T) gravity with the Lagrange multiplier and potential in a Universe containing, besides radiation and dark energy, a self-interacting (collisional) matter. We obtain through the modified Friedmann equations the main equation that can describe the cosmological evolution. Then, with several models from ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

Measurement of deuteron spectra and elliptic flow in Pb–Pb collisions at \(\sqrt{s_{\mathrm {NN}}}\) = 2.76 TeV at the LHC

The transverse momentum (\(p_\mathrm{T} \)) spectra and elliptic flow coefficient (\(v_{2}\)) of deuterons and anti-deuterons at mid-rapidity (\(|y|<0.5\)) are measured with the ALICE detector at the LHC in Pb–Pb collisions at \(\sqrt{s_{\mathrm {NN}}}\) = 2.76 TeV. The measurement of the \(p_\mathrm{T} \) spectra of (anti-)deuterons is done up to 8 GeV\(/c\) in 0–10% centrality ...