• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-05
Mehrab Momennia, Seyed Hossein Hendi

The recent reported gravitational wave detection motivates one to investigate the properties of different black hole models, especially their behavior under (axial) gravitational perturbation. Here, we study the quasinormal modes of black holes in Weyl gravity. We derive the master equation describing the quasinormal radiation by using a relation between the Schwarzschild-anti de Sitter black holes

更新日期：2020-06-05
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-05
M. Ghasemi-Nodehi, Youjun Lu, Ju Chen, Chao Yang

QPOs are seen as peak features in the X-ray power spectral density of stellar mass black holes and neutron stars, of which frequencies can be measured with high precision. These QPO frequencies are believed to be related to fundamental frequencies of test particles, which are mainly determined by the background metric. We consider the metric introduced in Ghasemi-Nodehi and Bambi (Eur Phys J C 76:290

更新日期：2020-06-05
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-05
A. A. Pankov, P. Osland, I. A. Serenkova, V. A. Bednyakov

The full ATLAS Run 2 data set with time-integrated luminosity of $$139 \, {\text {fb}}^{-1}$$ in the diboson channels in hadronic final states is used to probe a simple model with an extended gauge sector (EGM), proposed by Altarelli et al., and often taken as a convenient benchmark by experimentalists. This model accommodates new charged $$W'$$ and neutral $$Z'$$ vector bosons with modified trilinear

更新日期：2020-06-05
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-04
Juho Lankinen, Joonas Malmi, Iiro Vilja

We derive a curved space generalization of a scalar to fermion decay rate with a Yukawa coupling in expanding Friedmann–Robertson–Walker universes. This is done using the full theory of quantum fields in curved spacetime and the added-up transition probability method. It is found that in an expanding universe the usual Minkowskian decay rates are considerably modified for early times. For conformally

更新日期：2020-06-04
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
E. Rubín de Celis, C. Simeone

The problem of the electrostatics in conical wormholes is revisited, now improving the background geometries with asymptotical flatness. The electric self-force on a point charge placed at different regions in the spacetime of a conical thin-shell wormhole connecting flat outer submanifolds is obtained and compared with the results of previous works. The study is also carried out in terms of a previously

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
Batool Imtiaz, Rui Shi, Yi-Fu Cai

In this article we update constraints on superconducting cosmic strings (SCSs) in the light of the recent observational developments of fast radio bursts (FRBs) astronomy. Assuming strings follow an exponential distribution characterized by a current, we show that two parameters in our context, which are the characteristic tension ($$G\mu$$) and a parameter which describes the aforementioned exponential

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
Henning Bahl, Sven Heinemeyer, Wolfgang Hollik, Georg Weiglein

The remaining theoretical uncertainties from unknown higher-order corrections in the prediction for the light Higgs-boson mass of the MSSM are estimated. The uncertainties associated with three different approaches that are implemented in the publicly available code FeynHiggs are compared: the fixed-order diagrammatic approach, suitable for low SUSY scales, the effective field theory (EFT) approach

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
Debasish Borah, Arnab Dasgupta, Sin Kyu Kang

We propose a novel scenario of generating lepton asymmetry via annihilation and coannihilation of dark sector particles including t-channel processes. In order to realistically implement this idea, we consider the scotogenic model having three right handed neutrinos and a new scalar doublet, all of which are odd under an in-built $$Z_2$$ symmetry. The lightest $$Z_2$$ odd particle, if electromagnetically

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
Sudan Hansraj, Lushen Moodly

It is indeed remarkable that while charged anisotropic models with the embedding class one property are abundant, there are no reports of the physically important isotropic case despite its simplicity. In fact, the Karmarkar condition turns out to be the only avenue to generate all such stellar models algorithmically. The process of determining exact solutions is almost trivial: either specify the

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-03
S. Jadach, W. Płaczek, M. Skrzypek

All real and virtual infrared singularities in the standard analysis of the perturbative Quantum Electrodynamics (like that of Yennie–Frautschi–Suura) are associated with photon emissions from the external legs in the scattering process. External particles are stable, with the zero decay width. Such singularities are well understood at any perturbative order and are resummed. The case of production

更新日期：2020-06-03
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-02
Andrei L. Erofeev

Classical black holes are known for almost half a century to nullify exterior classical massive vector field associated with a charge crossing the event horizon. This implies that, from the point of view of an external observer, the Proca field of the charge is screened with the strength gradually increasing as the charge adiabatically approaches the event horizon. In this paper we reject the adiabaticity

更新日期：2020-06-02
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-02
Pei-Hong Gu

We present a purely linear seesaw mechanism in a mirror left-right symmetric framework and then realize a novel leptogenesis scenario for parametrizing the cosmic baryon asymmetry by the charged lepton masses, the light Majorana neutrino mass matrix and the heavy mirror charged lepton masses. Through the same Yukawa couplings, the lepton-number-conserving decays of the mirror charged leptons can generate

更新日期：2020-06-02
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-02
V. P. Gonçalves, B. D. Moreira

The photon – induced interactions, present in ep, eA, pp, pA, AA and $$e^+ e^-$$ collisions, are expressed within the color dipole approach in terms of the photon wave function, which describes the transition of the photon into a quark – antiquark color dipole. Such quantity is usually calculated using perturbation theory assuming that long distance corrections associated to strong interactions can

更新日期：2020-06-02
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-02
Chandrachur Chakraborty, Parthasarathi Majumdar

The exact precession frequency of a freely-precessing test gyroscope is derived for a $$2+1$$ dimensional rotating acoustic black hole analogue spacetime, without making the somewhat unrealistic assumption that the gyroscope is static. We show that, as a consequence, the gyroscope crosses the acoustic ergosphere of the black hole with a finite precession frequency, provided its angular velocity lies

更新日期：2020-06-02
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-01
Guoqiang Jin, Chengjie Fu, Puxun Wu, Hongwei Yu

The production of GWs during preheating in the Starobinsky model with a nonminimally coupled auxiliary scalar field is studied through the lattice simulation in this paper. We find that the GW spectrum $$\Omega _{\mathrm{gw}}$$ grows fast with the increase of the absolute value of coupling parameter $$\xi$$. This is because the resonant bands become broad with the increase of $$|\xi |$$. When $$\xi 更新日期：2020-06-01 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-01 Ángel Rincón, Ernesto Contreras, Francisco Tello-Ortiz, Pedro Bargueño, Gabriel Abellán In the present paper, we analyze the well-known 2+1 dimensional black holes (assuming a non-vanishing cosmological constant) in light of the gravitational decoupling by the minimal geometric deformation approach. To illustrate our results, we consider the BTZ geometry as the seed solution to generate new anisotropic ones. To complement the study, the curvature scalars and the energy conditions are 更新日期：2020-06-01 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-06-01 Xue-Mei Deng A black hole on a three-brane in five-dimensional spacetime was predicted by Dadhich, Maartens, Papadopoulos and Rezania (DMPR). In order to reveal some signatures for observations, we investigate a timelike particle’s motion around the DMPR brane-world black holes. We find that, both in the innermost stable circular orbits (ISCO) and the marginally bound orbits (MBO), the particle’s angular momentum 更新日期：2020-06-01 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-30 R. O. Coelho, V. P. Gonçalves, D. E. Martins, M. Rangel In this paper we present a detailed analysis of the contribution of the Light-by-Light (LbL), Durham and double diffractive processes for the diphoton production in ultraperipheral PbPb collisions at the Large Hadron Collider (LHC), High-Energy LHC (HE-LHC) and Future Circular Collider (FCC). The acceptance of the central and forward LHC detectors is taken into account and predictions for the invariant 更新日期：2020-05-30 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-30 N. A. Abdulov, A. V. Lipatov The \(\Upsilon (2S)$$ production and polarization at high energies is studied in the framework of $$k_T$$-factorization approach. Our consideration is based on the non-relativistic QCD formalism for bound states formation and off-shell production amplitudes for hard partonic subprocesses. The direct production mechanism, feed-down contributions from radiative $$\chi _b(3P)$$ and $$\chi _b(2P)$$ decays

更新日期：2020-05-30
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-30
A. Albert, M. André, M. Anghinolfi, G. Anton, M. Ardid, J.-J. Aubert, J. Aublin, B. Baret, S. Basa, B. Belhorma, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, M. Bouta, M. C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, A. Capone, L. Caramete, J. Carr, S. Celli, M. Chabab, T. N. Chau, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, A. Coleiro, M. Colomer Molla, R. Coniglione, P. Coyle

An offline search for a neutrino counterpart to gravitational-wave (GW) events detected during the second observation run (O2) of Advanced-LIGO and Advanced-Virgo performed with ANTARES data is presented. In addition to the search for long tracks induced by $$\nu _\mu$$ ($${\overline{\nu }}_{\mu }$$) charged current interactions, a search for showering events induced by interactions of neutrinos of

更新日期：2020-05-30
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-29
Christian Bierlich, Andy Buckley, Christian Holm Christensen, Peter Harald Lindenov Christiansen, Cody B. Duncan, Jan Fiete Grosse-Oetringhaus, Przemyslaw Karczmarczyk, Patrick Kirchgaeßer, Jochen Klein, Leif Lönnblad, Roberto Preghenella, Christine O. Rasmussen, Maria Stefaniak, Vytautas Vislavicius

The Rivet library is an important toolkit in particle physics, and serves as a repository for analysis data and code. It allows for comparisons between data and theoretical calculations of the final state of collision events. This paper outlines several recent additions and improvements to the framework to include support for analysis of heavy ion collision simulated data. The paper also presents examples

更新日期：2020-05-29
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-29
G. A. Carvalho, P. H. R. S. Moraes, S. I. dos Santos, B. S. Gonçalves, M. Malheiro

In this work we analyze hydrostatic equilibrium configurations of neutron stars in a non-minimal geometry-matter coupling (GMC) theory of gravity. We begin with the derivation of the hydrostatic equilibrium equations for the f(R, L) gravity theory, where R and L are the Ricci scalar and Lagrangian of matter, respectively. We assume $$f(R,L)=R/2+[1+\sigma R]L$$, with $$\sigma$$ constant. To describe

更新日期：2020-05-29
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-29
Orlando Oliveira, Tobias Frederico, Wayne de Paula

The Schwinger–Dyson quark equation (SDE) combined with results from lattice simulation for the propagators are used to obtain information on the quark-gluon vertex, taking into account the recent full QCD lattice results for the soft-gluon limit. Its inclusion leads to a clear enhancement of the infrared quark-gluon vertex. We also find that the relative contribution of the quark-ghost kernel to the

更新日期：2020-05-29
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-28
Sanjar Shaymatov, Naresh Dadhich, Bobomurat Ahmedov, Mubasher Jamil

Generally a black hole could be over-charged/spun, violating the weak cosmic censorship conjecture (WCCC) for linear order accretion while the same is always restored for non-linear accretion. The only exception, however, is that of a five-dimensional rotating black hole with single rotation, which cannot be overspun even at linear order. In this paper we investigate this question for a five-dimensional

更新日期：2020-05-28
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-28
Yuta Hamada, Masahiro Ibe, Yu Muramatsu, Kin-ya Oda, Norimi Yokozaki

We study the proton lifetime in the SO(10) Grand Unified Theory (GUT), which has the left–right (LR) symmetric gauge theory below the GUT scale. In particular, we focus on the minimal model without the bi-doublet Higgs field in the LR symmetric model, which predicts the LR-breaking scale at around $$10^{10-12}$$ GeV. The Wilson coefficients of the proton decay operators turn out to be considerably

更新日期：2020-05-28
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-28
David Benisty, Eduardo I. Guendelman, Emmanuel N. Saridakis

We propose a new approach to investigate inflation in a model-independent way, and in particular to elaborate the involved observables, through the introduction of the “scale factor potential”. Through its use one can immediately determine the inflation end, which corresponds to its first (and global) minimum. Additionally, we express the inflationary observables in terms of its logarithm, using as

更新日期：2020-05-28
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-27
Nicolas R. Bertini, Wiliam S. Hipólito-Ricaldi, Felipe de Melo-Santos, Davi C. Rodrigues

General relativity (GR) extensions based on renormalization group (RG) flows may lead to scale-dependent couplings with nontrivial effects at large distance scales. Here we develop further the approach in which RG effects at large distance scales are fully encoded in an effective action and we apply it to cosmology. In order to evaluate the cosmological consequences, our main assumption is the use

更新日期：2020-05-27
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-27
Iberê Kuntz, Roldão da Rocha

The Hawking radiation of static, spherically symmetric, asymptotically flat solutions in quadratic gravity is here scrutinized, in the context of the generalized uncertainty principle (GUP). Near-center and near-horizon Frobenius expansions of these solutions are studied. Their Hawking thermal spectrum is investigated out of the tunnelling method and the WKB procedure. Computing the Hawking flux of

更新日期：2020-05-27
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
L. Baudis, Y. Biondi, M. Galloway, F. Girard, S. Hochrein, S. Reichard, P. Sanchez-Lucas, K. Thieme, J. Wulf

For the first time, a small dual-phase (liquid/gas) xenon time projection chamber was equipped with a top array of silicon photomultipliers for light and charge readout. Here we describe the instrument in detail, as well as the data processing and the event position reconstruction algorithms. We obtain a spatial resolution of $$\sim 1.5\,\text {mm}$$ in the horizontal plane. To characterise the detector

更新日期：2020-05-26
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
N. Amburg, H. Itoyama, Andrei Mironov, Alexei Morozov, D. Vasiliev, R. Yoshioka

A novel functorial relationship in perturbative quantum field theory is pointed out that associates Feynman diagrams (FD) having no external line in one theory $$\mathbf{Th}_1$$ with singlet operators in another one $$\mathbf{Th}_2$$ having an additional $$U(\mathcal{N})$$ symmetry and is illustrated by the case where $$\mathbf{Th}_1$$ and $$\mathbf{Th}_2$$ are respectively the rank $$r-1$$ and the

更新日期：2020-05-26
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
Andrea Arduino, Riccardo Finotello, Igor Pesando

We consider time-dependent orbifolds in String Theory and we show that divergences are not associated with a gravitational backreaction since they appear in the open string sector too. They are related to the non existence of the underlying effective field theory as in several cases fourth and higher order contact terms do not exist. Since contact terms may arise from the exchange of string massive

更新日期：2020-05-26
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
Davood Mahdavian Yekta, Hanif Golchin

In the context of guage/gravity duality, we investigate the central charges of a number of 2-dimensional conformal field theories (CFTs) that might live on the boundary of some 3-dimensional (3D) toy models of gravity, from the thermodynamics aspect of the black holes. For many black hole solutions, the entropy product of the inner Cauchy and outer event horizons is universal (mass independent). It

更新日期：2020-05-26
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
W.-Z. Wei, R. Panth, J. Liu, H. Mei, D.-M. Mei, G.-J. Wang

Germanium (Ge) detectors with ability of measuring a single electron–hole (e–h) pair are needed in searching for light dark matter (LDM) down to the MeV scale. We investigate the feasibility of Ge detectors with amorphous-Ge (a-Ge) contacts to achieve the sensitivity of measuring a single e-h pair, which requires extremely low leakage current. Three Ge detectors with a-Ge contacts are used to study

更新日期：2020-05-26
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26
Yan Wang, Qi Wu, Gang Li, Ju-Jun Xie, Chun-Sheng An

We investigate the charmless decays of excited P-wave charmonia $$\chi _{c1}^\prime \rightarrow VV$$ and $$\chi _{c2}^\prime \rightarrow VP$$ via intermediate charmed meson loops, where V and P denote the light vector and pseudoscalar mesons, respectively. Within the model parameters, the charmed meson loop contributions are evaluated by using the effective Lagrangian approach. For $$\chi _{c1}^\prime 更新日期：2020-05-26 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-26 Maxim Dvornikov Spin oscillations of neutrinos, gravitationally scattered off a black hole (BH), are studied. The cases of nonrotating and rotating BHs are analyzed. We derive the analytic expressions for the transition and survival probabilities of spin oscillations when neutrinos interact with these gravitational backgrounds. The obtained transition probabilities depend on the impact parameter, as well as the neutrino 更新日期：2020-05-26 • Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25 Marco Guzzi, Nikolaos Kidonakis We study the production of a single top quark in association with a heavy extra \(Z'$$ at hadron colliders in new physics models with and without flavor-changing neutral-current (FCNC) couplings. We use QCD soft-gluon resummation and threshold expansions to calculate higher-order corrections for the total cross section and transverse-momentum distributions for $$t Z'$$ production. The impact of the

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25
M. Diehl, J. R. Gaunt, D. M. Lang, P. Plößl, A. Schäfer

Models for double parton distributions that are realistic and consistent with theoretical constraints are crucial for a reliable description of double parton scattering. We show how an ansatz that has the correct behaviour in the limit of small transverse distance between the partons can be improved step by step, such as to fulfil the sum rules for double parton distributions with an accuracy around

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25
Romulo Rougemont

By employing the holographic operator mixing technique to deal with coupled perturbations in the gauge/gravity duality, I numerically compute the real and imaginary parts of the diagonal and Hall AC conductivities in a strongly coupled quantum field theory dual to a bulk condensate of magnetic monopoles. The results obtained show that a conclusion previously derived in the literature, namely, the vanishing

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25
Osvaldo P. Santillán, Matías Sempé

The present work studies the dynamics of axion quark nuggets introduced in Zhitnitsky (JCAP 0310:010, 2003) and developed further in the works (Zhitnitsky in Phys Rev D 74:043515, 2006; Lawson and Zhitnitsky in Phys Lett B 724, 17, 2013; Lawson and Zhitnitsky in Phys Rev D 95:063521, 2017; Liang and Zhitnitsky in Phys Rev D 94:083502, 2016; Ge et al. in Phys Rev D 97:043008, 2018; Zhitnitsky in Phys

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25
Johannes Bellm, Stefan Gieseke, Patrick Kirchgaeßer

The modeling of multiple parton interactions in Monte Carlo event generators is a crucial part not only for the dressing of signal processes but also to describe data with a minimum bias on the event selection. Much work has and will be put into the theoretical framework and the numerical implementation of these models. In this contribution, we document various improvements of the multiple parton interaction

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-25
J. Benel, A. Courtoy, R. Ferro-Hernandez

We present a constrained analysis of the valence transversity Parton Distribution Functions from dihadron production in semi-inclusive DIS. While usual extractions of the transversity distributions rely explicitly on the fulfillment of the Soffer bound, the present analysis releases that restriction to implement further constraints through the method of Lagrange multipliers. The results are quantitatively

更新日期：2020-05-25
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-24
J. Ferretti, E. Santopinto, M. Naeem Anwar, Yu Lu

We calculate the masses of $$\chi _{\mathrm{c}}(3P)$$ states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of $$\chi _{\mathrm{c}}(2P)$$ and $$\chi _{\mathrm{b}}(3P)$$ multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the $$\chi _{\mathrm{c}}(3P)$$ states

更新日期：2020-05-24
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-23
C. Arias, F. Tello-Ortíz, E. Contreras

In this work we investigate the extra packing of mass within the framework of gravitational decoupling by means of Minimal Geometric Deformation approach. It is shown that, after a suitable set of the free parameters involved, the like-Tolman IV solution extended by Minimal Geometric Deformation not only acquire extra packing of mass but it corresponds to a stable configuration according to the adiabatic

更新日期：2020-05-23
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-22
Kai Xu, Han-Jie Zhu, Guo-Feng Zhang, Jie-Ci Wang, Wu-Ming Liu

We investigate the speedup evolution of the system under the influence of the Unruh effect, where one of the observers (e.g., Bob) is uniformly accelerated. We show that acceleration can be beneficial to the evolution speed of the system, even in the presence of noise. Here two distinct dissipation mechanisms are considered, one where the total system is in a noise channel and the second where only

更新日期：2020-05-22
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-22
A. Aduszkiewicz, E. V. Andronov, T. Antićić, V. Babkin, M. Baszczyk, S. Bhosale, A. Blondel, M. Bogomilov, A. Brandin, A. Bravar, W. Bryliński, J. Brzychczyk, M. Buryakov, O. Busygina, A. Bzdak, H. Cherif, M. Ćirković, M. Csanad, J. Cybowska, T. Czopowicz, A. Damyanova, N. Davis, M. Deliyergiyev, M. Deveaux, A. Dmitriev, W. Dominik, P. Dorosz, J. Dumarchez, R. Engel, G. A. Feofilov, L. Fields, Z. Fodor

The measurement of $$K^{*}(892)^0$$ resonance production via its $$K^{+}\pi ^{-}$$ decay mode in inelastic p+p collisions at beam momentum 158 $$\text{ Ge }\text{ V }\!/\!c$$ ($$\sqrt{s_{NN}}=17.3$$ $$\text{ Ge }\text{ V }$$) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The template method was used to extract the $$K^{*}(892)^0$$ signal

更新日期：2020-05-22
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-22
He-Xu Zhang, Cong Li, Peng-Zhang He, Qi-Qi Fan, Jian-Bo Deng

In this article, we have investigated the equations of motion of the photons coupled to Weyl tensor by the geometric optics approximation and the corresponding shadow in a Brane-World black hole spacetime. It is shown that there exists a double shadow for a black hole since the coupling photons with different polarization directions propagate along different paths in the spacetime. Furthermore, we

更新日期：2020-05-22
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-22
A. F. Ferrari, J. R. Nascimento, A. Yu. Petrov

Radiative corrections in Lorentz violating (LV) models have already received a lot of attention in the literature in recent years, with many instances where a LV operator in one sector of the Standard Model Extension (SME) generates, via loop corrections, one of the LV coefficients in the photon sector, which is probably the most understood and well constrained part of the SME. In many of these works

更新日期：2020-05-22
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-21
Subhajyoti Pal, Subenoy Chakraborty

We the authors want to further mention that the three fluid cosmological model has been considered before in some earlier works.

更新日期：2020-05-21
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-21
Dhimiter D. Canko, Ioannis D. Gialamas, George P. Kodaxis

We study a model including a real scalar field $$\phi$$ non-minimally coupled to $$F(\mathcal{R})$$ gravity, which is conformally equivalent to an Einstein–Hilbert theory, involving two real scalar fields. We consider three special cases of the potential of the field $$\phi$$ in the $$F(\mathcal{R})$$-frame: a vanishing potential, a mass term and a Higgs potential. All these lead to non-trivial two-field

更新日期：2020-05-21
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-21
Krzysztof Golec-Biernat, Tomasz Stebel

We discuss the Drell–Yan dilepton production using the transverse momentum dependent parton distributions evolved with the Catani–Ciafaloni–Fiorani–Marchesini–Kwieciński (CCFM-K) equations in the single loop approximation. Such equations are obtained assuming angular ordering of emitted partons (coherence) for $$x\sim 1$$ and transverse momentum ordering for $$x \ll 1$$. This evolution scheme also

更新日期：2020-05-21
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-21
J. de Blas, D. Chowdhury, M. Ciuchini, A. M. Coutinho, O. Eberhardt, M. Fedele, E. Franco, G. Grilli di Cortona, V. Miralles, S. Mishima, A. Paul, A. Peñuelas, M. Pierini, L. Reina, L. Silvestrini, M. Valli, R. Watanabe, N. Yokozaki

HEPfit is a flexible open-source tool which, given the Standard Model or any of its extensions, allows to (i) fit the model parameters to a given set of experimental observables; (ii) obtain predictions for observables. HEPfit can be used either in Monte Carlo mode, to perform a Bayesian Markov Chain Monte Carlo analysis of a given model, or as a library, to obtain predictions of observables for a

更新日期：2020-05-21
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-20
Shogo Nishino, Kei-Ichi Kondo

In the previous paper, we have shown the existence of magnetic monopoles in the pure SU(2) Yang–Mills theory with a gauge-invariant mass term for the gluon field being introduced. In this paper, we extend our previous construction of magnetic monopoles to obtain dyons with both magnetic and electric charges. In fact, we solve under the static and spherically symmetric ansatz the field equations of

更新日期：2020-05-20
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-20
Yixin Xu, Tiberiu Harko, Shahab Shahidi, Shi-Dong Liang

We consider an f(Q, T) type gravity model in which the scalar non-metricity $$Q_{\alpha \mu \nu }$$ of the space-time is expressed in its standard Weyl form, and it is fully determined by a vector field $$w_{\mu }$$. The field equations of the theory are obtained under the assumption of the vanishing of the total scalar curvature, a condition which is added into the gravitational action via a Lagrange

更新日期：2020-05-20
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-20
Raquel Molina, Eulogio Oset

We evaluate the contribution to the X(3872) width from a triangle mechanism in which the X decays into $$D^{*0}{\bar{D}}^0 -cc$$, then the $$D^{*0} ({\bar{D}}^{*0})$$ decays into $$D^0 \pi ^0$$ ($${\bar{D}}^0 \pi ^0$$) and the $$D^0 {\bar{D}}^0$$ fuse to produce $$\pi ^+ \pi ^-$$. This mechanism produces an asymmetric peak from a triangle singularity in the $$\pi ^+ \pi ^-$$ invariant mass with a shape

更新日期：2020-05-20
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-20
M. Albrecht, C. Amsler, W. Dünnweber, M. A. Faessler, F. H. Heinsius, H. Koch, B. Kopf, U. Kurilla, C. A. Meyer, K. Peters, J. Pychy, X. Qin, M. Steinke, U. Wiedner

A partial wave analysis of antiproton–proton annihilation data in flight at 900 $$\mathrm {MeV/}c$$ into $${\pi ^0\pi ^0\eta }$$, $${\pi ^0\eta \eta }$$ and $${K^+K^-\pi ^0}$$ is presented. The data were taken at LEAR by the Crystal Barrel experiment in 1996. The three channels have been coupled together with $$\pi \pi$$-scattering isospin I = 0 S- and D-wave as well as I = 1 P-wave data utilizing

更新日期：2020-05-20
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-20
Johannes Bellm, Gavin Bewick, Silvia Ferrario Ravasio, Stefan Gieseke, David Grellscheid, Patrick Kirchgaeßer, Frashër Loshaj, Mohammad R. Masouminia, Graeme Nail, Andreas Papaefstathiou, Simon Plätzer, Radek Podskubka, Michael Rauch, Christian Reuschle, Peter Richardson, Peter Schichtel, Michael H. Seymour, Andrzej Siódmok, Stephen Webster

A new release of the Monte Carlo event generator Herwig (version 7.2) is now available. This version introduces a number of improvements over the major version 7.0, notably: multi-jet merging with the dipole shower at LO and NLO QCD; spin correlations in both the dipole and angular-ordered parton showers; an improved choice of evolution variable in the angular-ordered parton shower; improvements to

更新日期：2020-05-20
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-19
H. Aounallah, A. R. Soares, R. L. L. Vitória

We have analyzed the effects of a simple wormhole, known as the Ellis–Bronnikov-type wormhole, on a scalar field, where, analytically, we determine solutions of bound states and show that the relativistic energy profile of this scalar field is drastically influenced by the topology of space-time characterized by the presence of a global monopole. Before this analysis, we investigated the effects of

更新日期：2020-05-19
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-19
Tommi Alanne, Florian Goertz

Conventional approaches to describe dark matter phenomenology at collider and (in)direct detection experiments in the form of dark matter effective field theory or simplified models suffer in general from drawbacks regarding validity at high energies and/or generality, limiting their applicability. In order to avoid these shortcomings, we propose a hybrid framework in the form of an effective theory

更新日期：2020-05-19
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-19
S. K. Maurya, Ksh. Newton Singh, B. Dayanandan

We presented a non-singular solution of Einstein’s field equations using gravitational decoupling by means of complete geometric deformation (CGD) in the anisotropic domain for compact star models. In this approach both the gravitational potentials are deformed as $$\nu =\xi +\beta \,h(r)$$ and $$e^{-\lambda }=\mu +\beta \,f(r)$$, where $$\beta$$ is a coupling constant. Then we solve more complex

更新日期：2020-05-19
• Eur. Phys. J. C (IF 4.843) Pub Date : 2020-05-19
Valerio Faraoni

A recent model predicting Omori’s law giving the number of aftershocks per unit time following an earthquake involves a differential equation analogous to the Friedmann equation of cosmology. The beforeshock phase is analogous to an accelerating universe approaching a Big Rip, the main shock to the Big Rip singularity, and the aftershock to a contracting universe. The analogy provides some physical

更新日期：2020-05-19
Contents have been reproduced by permission of the publishers.

down
wechat
bug