# The European Physical Journal C

## List of Papers (Total 4,485)

In the present work, we propose to search the charmonium-like states $$Z_c(3900$$) and $$Z_c(4020)$$ in the $$B_c$$ decay. In an effective Lagrangian approach, the branching ratios of $$B_c^+ \rightarrow Z_c(3900)^+ \pi ^0$$ and $$B_c^+\rightarrow Z_c (4020)^+ \pi ^0$$ are estimated to be of order of $$10^{-4}$$ and $$10^{-7}$$, respectively. The large production rate of $$Z_c... #### Effective action of a dynamical Dp-brane with background fluxes We shall construct the Dirac-Born-Infeld like and the Wess–Zumino like actions for a dynamical Dp-brane with the U(1) gauge potential and the Kalb–Ramond background field. The brane dynamics simultaneously has both tangential and transverse components. Our calculations will be in the context of the type II superstring theory, via the boundary state formalism. #### On the number of terms in the Lovelock products In this short note we wonder about the explicit expression of the expanding of the p-th Lovelock product. We use the 1990s’ works of S. A. Fulling et al. on the symmetries of the Riemann tensor, and we show that the number of independent scalars appearing in this expanding is equal to the number of Young diagrams with all row lengths even in the decomposition of the p-th plethysm... #### First particle-by-particle measurement of emittance in the Muon Ionization Cooling Experiment The Muon Ionization Cooling Experiment (MICE) collaboration seeks to demonstrate the feasibility of ionization cooling, the technique by which it is proposed to cool the muon beam at a future neutrino factory or muon collider. The emittance is measured from an ensemble of muons assembled from those that pass through the experiment. A pure muon ensemble is selected using a... #### Regular black holes and its thermodynamics in Lovelock gravity In this work two new families of non-singular or regular black hole solutions are displayed. These black holes behave as de Sitter space near its center and have a well defined AdS asymptotic region for negative cosmological constant. These solutions are constructed on a general ground through the introduction of a finite density of mass/energy. This removes the usual singularity... #### The Heisenberg spinor field classification and its interplay with the Lounesto’s classification Dirac linear spinor fields were obtained from non-linear Heisenberg spinors, in the literature. Here we extend that idea by considering not only Dirac spinor fields but spinor fields in any of the Lounesto’s classes. When one starts considering all these classes of fields, the question of providing a classification for the Heisenberg spinor naturally arises. In this work the... #### Perturbations of bounce inflation scenario from f(T) modified gravity revisited In this work, we revisit the perturbations that are generated in the bounce inflation scenario constructed within the framework of f(T) theory. It has been well known that pure f(T) theory cannot give rise to bounce inflation behavior, so aside from the gravity part, we also employ a canonical scalar field for minimal extension. We calculate the perturbations in f(T) theory using... #### Strong bounds on sum of neutrino masses in a 12 parameter extended scenario with non-phantom dynamical dark energy ( \(w(z)\ge -1$$ )

We obtained constraints on a 12 parameter extended cosmological scenario including non-phantom dynamical dark energy (NPDDE) with CPL parametrization. We also include the six $$\Lambda$$CDM parameters, number of relativistic neutrino species ($$N_{\text {eff}}$$) and sum over active neutrino masses ($$\sum m_{\nu }$$), tensor-to-scalar ratio ($$r_{0.05}$$), and running of the...

#### BasisGen: automatic generation of operator bases

BasisGen is a Python package for the automatic generation of bases of operators in effective field theories. It accepts any semisimple symmetry group and fields in any of its finite dimensional irreducible representations. It takes into account integration by parts redundancy and, optionally, the use of equations of motion. The implementation is based on well-known methods to...

#### Generating solutions for charged geodesic anisotropic spherical collapse with shear and heat radiation

In this paper we give a generating function for solutions of the type of collapse mentioned in the title. It satisfies a simple Riccati equation, derived from a formula, which holds in the interior of the star. The generating function is unique, unlike in the neutral case. Every neutral solution has a charged companion with the same generating function. The charged solution has...

#### Mirror symmetry of quantum Yang–Mills vacua and cosmological implications

We find an argument related to the existence of a $$\mathbb {Z}_2$$-symmetry for the renormalization group flow derived from the bare Yang–Mills Lagrangian, and show that the cancellation of the vacuum energy may arise motivated both from the renormalization group flow solutions and the effective Yang–Mills action. In the framework of the effective Savvidy’s action, two Mirror...

#### Meson excitation at finite chemical potential

We consider a probe stable meson in the holographic quark–gluon plasma at zero temperature and chemical potential. Due to the energy injection into the plasma, the temperature and chemical potential are increased to arbitrary finite values in such a way that the plasma experiences an out-of-equilibrium process. We then observe that the meson is excited, i.e. the expectation value...

#### Associated production of a top quark pair with a heavy electroweak gauge boson at NLO+NNLL accuracy

We perform threshold resummation of soft gluon corrections to the total cross sections and the invariant mass distributions for production of a top-antitop quark pair associated with a heavy electroweak boson $$V = W^+$$, $$W^-$$ or Z in pp collisions at the Large Hadron Collider. The resummation is carried out at next-to-next-to-leading-logarithmic (NNLL) accuracy using the...

#### Photon enhancement in a homogeneous axion dark matter background

We study the propagation of photons in a homogeneous axion dark matter background. When the axion decay into two photons is stimulated, the photon field exhibits a parametric instability in a small bandwidth centered on one half of the axion mass. We estimate analytically the enhancement for both coherent and non-coherent axion fields and we find that this effect could be...

#### Thermodynamics and weak cosmic censorship conjecture of the torus-like black hole

After studying the energy–momentum relation of charged particles’ Hamilton–Jacobi equations, we discuss the laws of thermodynamics and the weak cosmic censorship conjecture in torus-like black holes. We find that both the first law of thermodynamic as well as the weak cosmic censorship conjecture are valid in both the normal phase space and extended phase space. However, the...

#### The kurtosis of net baryon number fluctuations from a realistic Polyakov–Nambu–Jona-Lasinio model along the experimental freeze-out line

Firstly we qualitatively analyze the formation of the dip and peak structures of the kurtosis $$\kappa \sigma ^2$$ of net baryon number fluctuation along imagined freeze-out lines and discuss the signature of the existence of the QCD critical end point (CEP) in the Nambu–Jona-Lasinio (NJL) model, Polyakov-NJL (PNJL) model as well as $$\mu$$-dependent PNJL($$\mu$$ PNJL) model...

#### Clusters of Primordial Black Holes

The Primordial Black Holes (PBHs) are a well-established probe for new physics in the very early Universe. We discuss here the possibility of PBH agglomeration into clusters that may have several prominent observable features. The clusters can form due to closed domain walls appearance in the natural and hybrid inflation models whose subsequent evolution leads to PBH formation...

We study supersymmetric $$AdS_3\times \Sigma _2$$ and $$AdS_2\times \Sigma _3$$ solutions, with $$\Sigma _2=S^2,H^2$$ and $$\Sigma _3=S^3,H^3$$, in five-dimensional $$N=4$$ gauged supergravity coupled to five vector multiplets. The gauge groups considered here are $$U(1)\times SU(2)\times SU(2)$$, $$U(1)\times SO(3,1)$$ and $$U(1)\times SL(3,\mathbb {R})$$. For $$U(1)\times SU(2... #### Slowly rotating Einstein–Maxwell-dilaton black hole and some aspects of its thermodynamics A slowly rotating black hole solution in Einstein–Maxwell-dilaton gravity is considered. Using the obtained solution we investigate thermodynamic functions such as the black hole’s temperature, entropy and heat capacity. In addition, to examine the thermodynamic properties of the black hole an extended technique is applied. The equation of state of Van der Waals type is obtained... #### Final taus and initial state polarization signatures from effective interactions of Majorana neutrinos at future \(e^{+}e^{-}$$ colliders

We study the possibility of future $$e^{+}e^{-}$$ colliders to disentangle different new physics contributions to the production of heavy sterile Majorana neutrinos in the lepton number violating channel $$e^{+}e^{-}\rightarrow l^{+} l^{+}+ 4 {\text {jets}}$$, with $$l=e, \mu , \tau$$. This is done investigating the final anti-tau polarization trails and initial beam...

#### Imprints of quantum gravity in the cosmic microwave background

It has been shown that the spectrum of quantum gravity contains at least two new modes in addition to the massless graviton: a massive spin-0 and a massive spin-2. We calculate their power spectrum during inflation and we argue that they could leave an imprint in the cosmic microwave background should their masses be below the inflationary scale.

#### The Phillips–Barger model for the elastic cross section and the Odderon

Inspired by the recent TOTEM data for the elastic proton–proton (pp) scattering at $$\sqrt{s} =$$ 8 and 13 TeV, we update previous studies of the differential cross sections using the Phillips–Barger (PB) model, which parametrizes the amplitude in terms of a small number of free parameters. We demonstrate that this model is able to describe the recent pp data on a statistically...

#### Low energy spectrum of SU(2) lattice gauge theory

Prepotential formulation of gauge theories on honeycomb lattice yields local loop states, which are exact and orthonormal being free from any spurious loop degrees of freedom. We illustrate that, the dynamics of orthonormal loop states are exactly same in both the square and honeycomb lattices. We further extend this construction to arbitrary dimensions. Utilizing this result, we...

#### Relative particle yield fluctuations in $$\text{ Pb--Pb }$$ collisions at $$\sqrt{s_\mathrm{{NN}}} =2.76\hbox { TeV}$$

First results on $$\hbox {K}/\pi$$, $$\hbox {p}/\pi$$ and K/p fluctuations are obtained with the ALICE detector at the CERN LHC as a function of centrality in $$\text{ Pb--Pb }$$ collisions at $$\sqrt{s_\mathrm{{NN}}} =2.76\hbox { TeV}$$. The observable $$\nu _{\mathrm{dyn}}$$, which is defined in terms of the moments of particle multiplicity distributions, is used to quantify...

#### ANAIS-112 sensitivity in the search for dark matter annual modulation

The annual modulation measured by the  DAMA/LIBRA experiment can be explained by the interaction of dark matter WIMPs in NaI(Tl) scintillator detectors. Other experiments, with different targets or techniques, exclude the region of parameters singled out by  DAMA/LIBRA,  but the comparison of their results relies on several hypotheses regarding the dark matter model. ANAIS-112 is...