• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15
Antonella Cid, Carlos Rodriguez-Benites, Mauricio Cataldo, Gonzalo Casanova

We perform a Bayesian model selection analysis for interacting scenarios of dark matter and modified holographic Ricci dark energy (MHRDE) with linear interacting terms. We use a combination of some of the latest cosmological data such as type Ia supernovae, cosmic chronometers, the local value of the Hubble constant, baryon acoustic oscillations measurements and cosmic microwave background through

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15

The main method for calibrating the luminosity at Large Hadron Collider (LHC) is van der Meer scan where the beams are swept transversely across each other. This beautiful method was invented in 1968. Despite the honourable age, it remains the preferable tool at hadron colliders. It delivers the lowest calibration systematics, which still often dominates the overall luminosity uncertainty at LHC experiments

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15
Ya-Bing Zuo, Chong-Xing Yue, Bo Yu, Ying-Hui Kou, Yan Chen, Wen Ling

In the present work, the form factors of $$B_{(s)}$$ to light P-wave tensor mesons ($$a_2(1320)$$, $$K^*_2(1430)$$, $$f_2(1270)$$, $$f^\prime _2(1525)$$) are calculated via the light cone sum rules (LCSR) in the framework of heavy quark effective field theory (HQEFT). Firstly, the expressions of form factors in terms of the light cone distribution amplitudes (DAs) of tensor mesons are derived via the

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15
Fernando Arias-Aragón, Enrique Fernández-Martínez, Manuel González-López, Luca Merlo

The recent tension between local and early measurements of the Hubble constant can be explained in a particle physics context. A mechanism is presented where this tension is alleviated due to the presence of a Majoron, arising from the spontaneous breaking of Lepton Number. The lightness of the active neutrinos is consistently explained. Moreover, this mechanism is shown to be embeddable in the minimal

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15
G. Aad, B. Abbott, D. C. Abbott, A. Abed Abud, K. Abeling, D. K. Abhayasinghe, S. H. Abidi, O. S. AbouZeid, N. L. Abraham, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, B. Achkar, L. Adam, C. Adam Bourdarios, L. Adamczyk, L. Adamek, J. Adelman, M. Adersberger, A. Adiguzel, S. Adorni, T. Adye, A. A. Affolder, Y. Afik, C. Agapopoulou, M. N. Agaras, A. Aggarwal, C. Agheorghiesei, J. A. Aguilar-Saavedra

In the published HTML version of this article, the affiliations of the authors of the National Research Nuclear University MEPhI, Moscow, Russia were unfortunately marked incorrectly.

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-15
M. Crispim Romão, N. F. Castro, R. Pedro

In this paper we propose a new strategy, based on anomaly detection methods, to search for new physics phenomena at colliders independently of the details of such new events. For this purpose, machine learning techniques are trained using Standard Model events, with the corresponding outputs being sensitive to physics beyond it. We explore three novel AD methods in HEP: Isolation Forest, Histogram-Based

更新日期：2021-01-15
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
Valerio Faraoni, Geneviève Vachon

A four-force parallel to the trajectory of a massive particle can always be eliminated by going to an affine parametrization, but the affine parameter is different from the proper time. The main application is to cosmology, in which elements of the cosmic fluid are subject to a pressure gradient parallel to their four-velocities. Natural implementations of parallel four-forces occur when the particle

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
Jacob Sonnenschein, Dorin Weissman

Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at around 7240 MeV, very near to the threshold of two doubly charmed $$\Xi _{cc}$$ baryons. We argue in this note that these exotic hadrons are genuine tetraquarks and

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
Wei-Can Yang, Chuan-Yin Xia, Hua-Bi Zeng, Hai-Qing Zhang

At finite temperature, the stable equilibrium states of coupled two-component Bose Einstein condensations (BECs) with the same conformal mass in both non-rotating and rotating condition can be obtained by studying its real dynamics via holography. The equilibrium state is the state where the free energy reaches the minimum and does not change any more. In the case of no rotation, the spatial phase

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
João Luís Rosa, D. A. Ferreira, Dionisio Bazeia, Francisco S. N. Lobo

In this work, we study 5-dimensional braneworld scenarios in the scalar-tensor representation of the generalized hybrid metric-Palatini gravitational theory. We start by considering a model for a brane supported purely by the gravitational scalar fields of the theory and then consider other distinct cases where the models are also supported by an additional matter scalar field. We investigate the stability

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13

We introduce three families of classical and quantum solutions to the leading order of string effective action on spatially homogeneous $$(2+1)$$-dimensional space-times with the sources given by the contributions of dilaton, antisymmetric gauge B-field, and central charge deficit term $$\varLambda$$. At the quantum level, solutions of Wheeler–DeWitt equations have been enriched by considering the

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
O. A. Mattos, T. Frederico, O. Lourenço

The confinement/deconfinement transition described the Polyakov–Nambu–Jona–Lasinio (PNJL) model is extended to be operative at zero temperature regime. In this study, the scalar and vector channel interaction strengths of the original PNJL model are modified by introducing a dependence on the traced Polyakov loop. In such a way the effective interactions depend on the quark phase and in turn provides

更新日期：2021-01-14
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-13
Josef Klusoň

In this short note we perform canonical analysis of geometrical action for Dp-brane. We also discuss tachyon condensation in case of the geometrical action for unstable D(p+1)-brane.

更新日期：2021-01-13
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-12
H. Nematollahi, P. Abolhadi, S. Atashbar, A. Mirjalili, M. M. Yazdanpanah

We extract the polarized parton distribution functions (PPDFs) of proton. To this end we do a global analysis on recent and up-to-dated experimental data of polarized nucleon and deuteron structure functions at the NLO accuracy of perturbative QCD. We use the Jacobi polynomials expansion technique to do the required analyses. To achieve a more realistic estimation of the PPDFs and observable uncertainties

更新日期：2021-01-13
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-12

Gravitational critical collapse in the Einstein-axion-dilaton system is known to lead to continuous self-similar solutions characterized by the Choptuik critical exponent $$\gamma$$. We complete the existing literature on the subject by computing the linear perturbation equations in the case where the axion-dilaton system assumes a parabolic form. Next, we solve the perturbation equations in a newly

更新日期：2021-01-12
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-12
M. Z. Bhatti, Z. Yousaf, Z. Tariq

In this manuscript, the Riemann tensor is split orthogonally to get five scalar functions known as structure scalars which have significance to gain insight into the composition and structure of spherically symmetric self-gravitating objects. Certain stellar equations are then evaluated to gather information about physical characteristics of such astrophysical objects. These stellar equations are further

更新日期：2021-01-12
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-12
Coraline Stasser, Guy Terwagne, Jacob Lamblin, Olivier Méplan, Guillaume Pignol, Bernard Coupé, Silva Kalcheva, Steven Van Dyck, Michaël Sarrazin

MURMUR is a new passing-through-walls neutron experiment designed to constrain neutron-hidden neutron transitions allowed in the context of braneworld scenarios or mirror matter models. A nuclear reactor can act as a source of hidden neutrons, such that neutrons travel through a hidden world or sector. Hidden neutrons can propagate out of the nuclear core and far beyond the biological shielding. However

更新日期：2021-01-12
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-11
Xiaogang Zheng, Shuo Cao, Yuting Liu, Marek Biesiada, Tonghua Liu, Shuaibo Geng, Yujie Lian, Wuzheng Guo

In order to estimate cosmic curvature from cosmological probes like standard candles, one has to measure the luminosity distance $$D_L(z)$$, its derivative with respect to redshift $$D'_L(z)$$ and the expansion rate H(z) at the same redshift. In this paper, we study how such idea could be implemented with future generation of space-based DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO)

更新日期：2021-01-12
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-11
G. Aad, B. Abbott, D. C. Abbott, A. Abed Abud, K. Abeling, D. K. Abhayasinghe, S. H. Abidi, O. S. AbouZeid, N. L. Abraham, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, B. Achkar, L. Adam, C. Adam Bourdarios, L. Adamczyk, L. Adamek, J. Adelman, M. Adersberger, A. Adiguzel, S. Adorni, T. Adye, A. A. Affolder, Y. Afik, C. Agapopoulou, M. N. Agaras, A. Aggarwal, C. Agheorghiesei, J. A. Aguilar-Saavedra

A search is presented for new phenomena in events characterised by high jet multiplicity, no leptons (electrons or muons), and four or more jets originating from the fragmentation of b-quarks (b-jets). The search uses $$139~\hbox {fb}^{-1}$$ of $$\sqrt{s}$$ = 13 TeV proton–proton collision data collected by the ATLAS experiment at the Large Hadron Collider during Run 2. The dominant Standard Model

更新日期：2021-01-11
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-11
Yilong Xie, Gang Chen, Laszlo Pal Csernai

With the PICR hydrodynamic model, we study the polarization splitting between $$\varLambda$$ and $$\bar{\varLambda }$$ at RHIC BES energy range, based on the meson field mechanism. Our results fit to the experimental data fairly well. Besides, two unexpected effect emerges: (1) the baryon density gradient has non-trivial and negative contribution to the polarization splitting; (2) for 7.7 GeV Au+Au

更新日期：2021-01-11
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-11
A. M. Sirunyan, A. Tumasyan, W. Adam, T. Bergauer, M. Dragicevic, J. Erö, A. Escalante Del Valle, R. Frühwirth, M. Jeitler, N. Krammer, L. Lechner, D. Liko, T. Madlener, I. Mikulec, F. M. Pitters, N. Rad, J. Schieck, R. Schöfbeck, M. Spanring, S. Templ, W. Waltenberger, C.-E. Wulz, M. Zarucki, V. Chekhovsky, A. Litomin, V. Makarenko, J. Suarez Gonzalez, M. R. Darwish, E. A. De Wolf, D. Di Croce, X

A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton–proton collision data at a center-of-mass energy of 13$$\,\text {Te}\text {V}$$, collected by the CMS experiment at the LHC in 2016–2018, corresponding to an integrated luminosity of 137$$\,\text {fb}^{-1}$$. The search uses the decay channels

更新日期：2021-01-11
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-09
L. N. Granda, D. F. Jimenez

The Mukhanov–Sasaki equation is deduced from linear perturbations for a general scalar-tensor model with non-minimal coupling to curvature, to the Gauss–Bonnet invariant and non-minimal kinetic coupling to curvature. The general formulas for the power spectra of the primordial scalar and tensor fluctuations are obtained for arbitrary coupling functions. The results have been applied to models with

更新日期：2021-01-10
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-08
F. Gómez, S. Lepe, P. Salgado

From the field equations corresponding to a four-dimensional brane embedded in the five-dimensional spacetime of the Einstein–Chern–Simons theory for gravity, we find cosmological solutions that describe an accelerated expansion for a flat universe. Apart from a quintessence-type evolution scheme, we obtain a transient phantom evolution, which is not ruled out by the current observational data. Additionally

更新日期：2021-01-10
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-08

In this paper, we have investigated that the power law variation of Brans–Dicke scalar field $$(\phi )$$ with scale factor (a) is not validated by field equations in general for the Universe filled with dark matter and Tsallis type holographic dark energy. However, for specific choice of free parameters $$(\omega = -\frac{3}{2}$$ and $$n = -1)$$ which are differ from its values fixed in Ghaffari et

更新日期：2021-01-08
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-08
Fernanda Alvarim Silveira, Rodrigo Maier, Santiago Esteban Perez Bergliaffa

We present the features of a model which generalizes Schwarzschild’s homogeneous star by adding a transition zone for the density near the surface. By numerically integrating the modified TOV equations for the $$f(\mathcal {R})=\mathcal {R}+\lambda \mathcal {R}^2$$ Palatini theory, it is shown that the ensuing configurations are everywhere finite. Depending on the values of the relevant parameters

更新日期：2021-01-08
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-06
Jin-Li Zhang, Zhu-Fang Cui, Jia-Lun Ping, Craig D. Roberts

A contact interaction is used to calculate an array of pion twist-two, -three and -four generalised transverse light-front momentum dependent parton distribution functions (GTMDs). Despite the interaction’s simplicity, many of the results are physically relevant, amongst them a statement that GTMD size and shape are largely prescribed by the scale of emergent hadronic mass. Moreover, proceeding from

更新日期：2021-01-07
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-06
Jun Song, Hai-hong Li, Feng-lan Shao

We apply a quark combination model with equal-velocity combination (EVC) approximation to study the elliptic flow ($$v_{2}$$) of hadrons in heavy-ion collisions in a wide collision energy range ($$\sqrt{s_{NN}}=$$ 27–5020 GeV). Utilizing the simple relationship between $$v_{2}$$ of hadrons and those of quarks under EVC, we find that $$v_{2}$$ of up/down quarks obtained by experimental data of proton

更新日期：2021-01-06
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-05
Alessandro D. A. M. Spallicci, José A. Helayël-Neto, Martín López-Corredoira, Salvatore Capozziello

The total red shift z might be recast as a combination of the expansion red shift and a static shift due to the energy–momentum tensor non-conservation of a photon propagating through Electro-Magnetic (EM) fields. If massive, the photon may be described by the de Broglie–Proca (dBP) theory which satisfies the Lorentz(-Poincaré) Symmetry (LoSy) but not gauge-invariance. The latter is regained in the

更新日期：2021-01-05
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-05
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi, T. Bergauer, M. Dragicevic, J. Erö, A. Escalante Del Valle, R. Frühwirth, M. Jeitler, N. Krammer, L. Lechner, D. Liko, T. Madlener, I. Mikulec, F. M. Pitters, N. Rad, J. Schieck, R. Schöfbeck, M. Spanring, S. Templ, W. Waltenberger, C.-E. Wulz, M. Zarucki, V. Chekhovsky, A. Litomin, V. Makarenko, J. Suarez Gonzalez, M. R. Darwish, E. A. De Wolf, D.

A search is presented for supersymmetric partners of the top quark (top squarks) in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from $${\text {b}}$$quarks, and missing transverse momentum. The search uses data from proton-proton collisions at $$\sqrt{s}=13\,\text {TeV}$$ collected with the CMS detector, corresponding to an integrated luminosity

更新日期：2021-01-05
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-02

We propose a new strategy for the determination of the step scaling function $$\sigma (u)$$ in finite size scaling studies using the gradient flow. In this approach the determination of $$\sigma (u)$$ is broken in two pieces: a change of the flow time at fixed physical size, and a change of the size of the system at fixed flow time. Using both perturbative arguments and a set of simulations in the

更新日期：2021-01-02
• Eur. Phys. J. C (IF 4.389) Pub Date : 2021-01-02
Pilar Coloma, Patrick Huber, Thomas Schwetz

A considerable experimental effort is currently under way to test the persistent hints for oscillations due to an eV-scale sterile neutrino in the data of various reactor neutrino experiments. The assessment of the statistical significance of these hints is usually based on Wilks’ theorem, whereby the assumption is made that the log-likelihood is $$\chi ^2$$-distributed. However, it is well known that

更新日期：2021-01-02
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-30
Rashidul Hoque, B. J. Hazarika, D. K. Choudhury

We make an analysis of three -loop effects of the strong coupling constant in the study of masses and decay constants of the heavy-flavour pseudo-scalar mesons (PSM) D, $$D_s$$ , B, $$B_s,$$ $$B_c$$, $$\eta _c$$ and $$\eta _b$$ in a non-relativistic QCD potential model using Dalgarno’s perturbation theory (DPT). The first order mesonic wavefunction is obtained using Dalgarno’s perturbation theory.

更新日期：2020-12-30
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29
G. Abbas, A. Ditta

The accretion of test fluids flowing onto a black hole is investigated. Particularly, by adopting a dynamical Hamiltonian approach, we are capable to find the critical points for various cases of black hole in conformal gravity. In these cases, we have analyzed the general solutions of accretion employing the isothermal equations of state. The steady state and spherically symmetric accretion of different

更新日期：2020-12-30
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29
Xing-Xing Dong, Tai-Fu Feng, Shu-Min Zhao, Hai-Bin Zhang

In order to interpret the Higgs boson mass and its decays naturally, we hope to examine the BLMSSM and B-LSSM. In the both models, the right-handed neutrino superfields are introduced to better explain the neutrino mass problems. In this paper, we introduce the fine-tuning to acquire the physical Higgs boson mass. Besides, the method of $$\chi ^2$$ analyses will be adopted in the BLMSSM and B-LSSM

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29
Kourosh Nozari, Milad Hajebrahimi, Sara Saghafi

It is well known that quantum effects may lead to removal of the intrinsic singularity point of back holes. Also, the quintessence scalar field is a candidate model for describing late-time acceleration expansion. Accordingly, Kazakov and Solodukhin considered the existence of back-reaction of the spacetime due to the quantum fluctuations of the background metric to deform a Schwarzschild black hole

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29
Liang Ma, H. Lü

We consider the action principles that are the lower dimensional limits of the Einstein–Gauss–Bonnet gravity via the Kaluza–Klein route. We study the vacua and obtain some exact solutions. We find that the reality condition of the theories may select one vacuum over the other from the two vacua that typically arise in Einstein–Gauss–Bonnet gravity. We obtain exact black hole and cosmological solutions

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29
A. M. Velasquez-Toribio, Júlio C. Fabris

In the present investigation we use observational data of $$f \sigma _ {8}$$ to determine observational constraints in the plane $$(\Omega _{m0},\sigma _{8})$$ using two different methods: the growth factor parametrization and the numerical solutions method for density contrast, $$\delta _{m}$$. We verified the correspondence between both methods for three models of accelerated expansion: the $$\Lambda 更新日期：2020-12-29 • Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29 Philip Bechtle, Daniel Dercks, Sven Heinemeyer, Tobias Klingl, Tim Stefaniak, Georg Weiglein, Jonas Wittbrodt We describe recent developments of the public computer code HiggsBounds. In particular, these include the incorporation of LHC Higgs search results from Run 2 at a center-of-mass energy of 13 TeV, and an updated and extended framework for the theoretical input that accounts for improved Higgs cross section and branching ratio predictions and new search channels. We furthermore discuss an improved method 更新日期：2020-12-29 • Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29 Hisakazu Minakata Observation of the interference between the atmospheric and solar oscillation waves with the correct magnitude would provide another manifestation of the three-generation structure of leptons. As a prerequisite for such analyses we develop a method for decomposing the oscillation S matrix into the atmospheric and solar amplitudes. Though the similar method was recently proposed successfully in vacuum 更新日期：2020-12-29 • Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-29 Daniela D. Doneva, Lucas G. Collodel, Christian J. Krüger, Stoytcho S. Yazadjiev In the present paper we study the onset of the spin-induced scalarization of a Kerr black hole in scalar-Gauss–Bonnet gravity with a massive scalar field. Our approach is based on a \((2+1)$$ time evolution of the relevant linearized scalar field perturbation equation. We examine the region where the Kerr black hole becomes unstable giving rise to new scalarized rotating black holes with a massive

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-28
Fabio Moretti, Flavio Bombacigno, Giovanni Montani

We establish the possibility of Landau damping for gravitational scalar waves which propagate in a non-collisional gas of particles. In particular, under the hypothesis of homogeneity and isotropy, we describe the medium at the equilibrium with a Jüttner–Maxwell distribution, and we analytically determine the damping rate from the Vlasov equation. We find that damping occurs only if the phase velocity

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-28
Yang Liu

We employ a ghost model of interacting dark energy to obtain the equation of state $$\omega$$ for ghost energy density in an FRW universe in complex quintessence theory. We reconstruct the potential and study the dynamics of the scalar field that describes complex quintessence cosmology. We perform $$\omega -\omega '$$ analysis and stability analysis for both non-interacting and interacting cases

更新日期：2020-12-29
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-28
Marco Barsanti, Stefano Bolognesi, Fabrizio Canfora, Gianni Tallarita

We study the baby Skyrme model in (2+1)-dimensions built on a finite cylinder. To this end, we introduce a consistent ansatz which is able to reduce the complete set of field equations to just one equation for the profile function for arbitrary baryon charge. Many analytic solutions both with and without the inclusion of the effects of the minimal coupling with the Maxwell field are constructed. The

更新日期：2020-12-28
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-28
Dominik Döring, Heinrich Päs, Philipp Sicking, Thomas J. Weiler

Recently the MiniBooNE Collaboration has confirmed its anomalous excess in $$\overset{\scriptscriptstyle (-)}{\nu }_\mu \rightarrow \overset{\scriptscriptstyle (-)}{\nu }_e$$ neutrino oscillation data. Combined with long-standing results from the LSND experiment this amounts to a $$6.1\,\sigma$$ evidence for new physics beyond the Standard Model. In this paper we develop a framework with 3 active

更新日期：2020-12-28
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-28
A. Triantafyllopoulos, S. Basilakos, E. Kapsabelis, P. C. Stavrinos

In this work, we extend for the first time the spherically symmetric Schwarzschild and Schwarzschild–De Sitter solutions with a Finsler–Randers-type perturbation which is generated by a covector $$A_\gamma$$. This gives a locally anisotropic character to the metric and induces a deviation from the Riemannian models of gravity. A natural framework for this study is the Lorentz tangent bundle of a spacetime

更新日期：2020-12-28
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
K. Azizi, A. R. Olamaei, S. Rostami

We calculate the strong coupling constants among the doubly heavy spin-$$\frac{3}{2}$$ baryons $$\Xi ^*_{QQ}$$ and $$\Omega ^*_{QQ}$$, with Q and $$Q'$$ being c or b quark, with light vector meson by means of the light-cone QCD sum rules. The matrix elements defining these vertices are described by four coupling constants $$g_1$$, $$g_2$$, $$g_3$$, and $$g_4$$. The unwanted pollution coming

更新日期：2020-12-25
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Ugur Atli, Omer Guleryuz, Mehmet Ozkan

We provide a tensor calculus for n-number of $${\mathcal {N}}= (1,0)$$ linear multiplets in six dimensions. The coupling of linear multiplets is encoded in a function $${\mathcal {F}}_{IJ}$$ that is subject to certain constraints. We provide various rigid and local supersymmetric models depending on the choice of the function $${\mathcal {F}}_{IJ}$$ and provide an interesting off-diagonal superinvariant

更新日期：2020-12-25
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
John D. Barrow, Spiros Cotsakis, Dimitrios Trachilis

We construct a formal asymptotic series expansion for a general solution of the Brans–Dicke equations with a fluid source near a sudden singularity. This solution contains 11 independent arbitrary functions of the spatial coordinates as required by the Cauchy problem of the theory. We show that the solution is geodesically complete and has the character of a shock wave in the sudden asymptotic region

更新日期：2020-12-25
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
M. Vijaya Santhi, Y. Sobhanbabu

In this paper, we have investigated Tsallis holographic dark energy (infrared cutoff is the Hubble radius) in homogeneous and anisotropic Bianchi type-III Universe within the framework of Saez–Ballester scalar–tensor theory of gravitation. We have constructed non-interaction and interaction dark energy models by solving the Saez–Ballester field equations. To solve the field equations, we assume a relationship

更新日期：2020-12-25
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Melina Gómez Bock, Martin Hentschinski, Agustín Sabio Vera

We present an effective action for the electroweak sector of the standard model valid for the calculation of scattering amplitudes in the high energy (Regge) limit. Gauge invariant Wilson lines are introduced to describe reggeized degrees of freedom whose interactions are generated by effective emission vertices. From this approach previous results at leading logarithmic accuracy for electroweak boson

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Peng-Zhang He, Qi-Qi Fan, Hao-Ran Zhang, Jian-Bo Deng

Motivated by recent work on rotating black hole shadow (Chang and Zhu in Phys Rev D 101:084029, 2020), we investigate the shadow behaviours of rotating Hayward–de Sitter black hole for static observers at a finite distance in terms of astronomical observables. This paper uses the newly introduced distortion parameter (Chang and Zhu in Phys Rev D 102:044012, 2020) to describe the shadow’s shape quantitatively

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
G. Aad, B. Abbott, D. C. Abbott, A. Abed Abud, K. Abeling, D. K. Abhayasinghe, S. H. Abidi, O. S. AbouZeid, N. L. Abraham, H. Abramowicz, H. Abreu, Y. Abulaiti, B. S. Acharya, B. Achkar, L. Adam, C. Adam Bourdarios, L. Adamczyk, L. Adamek, J. Adelman, M. Adersberger, A. Adiguzel, S. Adorni, T. Adye, A. A. Affolder, Y. Afik, C. Agapopoulou, M. N. Agaras, A. Aggarwal, C. Agheorghiesei, J. A. Aguilar-Saavedra

The performance of the ATLAS Inner Detector alignment has been studied using pp collision data at $$\sqrt{s} = 13\,\hbox {TeV}$$ collected by the ATLAS experiment during Run 2 (2015–2018) of the Large Hadron Collider (LHC). The goal of the detector alignment is to determine the detector geometry as accurately as possible and correct for time-dependent movements. The Inner Detector alignment is based

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Zhi-Yong Zhou, Zhiguang Xiao

In this paper, we present how the Friedrichs–Lee model could be extended to the relativistic scenario and be combined with the relativistic quark pair creation model in a consistent way. This scheme could be applied to study the “unquenched” effect of the meson spectra. As an example, if the lowest $$J^{PC}=0^{++}$$ $$(u\bar{u}+d\bar{d})/\sqrt{2}$$ bound state in the potential model is coupled to the

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Rafel Escribano, Emilio Royo

A complete theoretical analysis of the C- conserving semileptonic decays $$\eta ^{(\prime )}\rightarrow \pi ^0l^+l^-$$ and $$\eta ^\prime \rightarrow \eta l^+l^-$$ ($$l=e$$ or $$\mu$$) is carried out within the framework of the Vector Meson Dominance (VMD) model. An existing phenomenological model is used to parametrise the VMD coupling constants and the associated numerical values are obtained from

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-24
Genly Leon, Alfredo D. Millano, Joey Latta

The asymptotic properties of conformally static metrics in Einstein–æther theory with a perfect fluid source and a scalar field are analyzed. In case of perfect fluid, some relativistic solutions are recovered such as: Minkowski spacetime, the Kasner solution, a flat FLRW space and static orbits depending on the barotropic parameter $$\gamma$$. To analyze locally the behavior of the solutions near

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-23
V. Andreev, A. Baghdasaryan, A. Baty, K. Begzsuren, A. Belousov, A. Bolz, V. Boudry, G. Brandt, D. Britzger, A. Buniatyan, L. Bystritskaya, A. J. Campbell, K. B. Cantun Avila, K. Cerny, V. Chekelian, Z. Chen, J. G. Contreras, J. Cvach, J. B. Dainton, K. Daum, A. Deshpande, C. Diaconu, G. Eckerlin, S. Egli, E. Elsen, L. Favart, A. Fedotov, J. Feltesse, M. Fleischer, A. Fomenko, C. Gal, J. Gayler, L

Exclusive photoproduction of $${{\rho ^0}} (770)$$ mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction $$\gamma p \rightarrow \pi ^{+}\pi ^{-}Y$$. Reactions where the proton stays intact ($${{{m_Y}} {=}m_p}$$) are statistically separated from those where the proton dissociates

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-23
Kerem Cankoçak, Durmuş Demir, Canan Karahan, Sercan Şen

What is the luminosity needed for discovering new physics if the electroweak scale is to remain stable? In this work we study this question, with the pertinent example of a real singlet scalar which couples to the Higgs field at the renormalizable level. Observing that the electroweak scale remains stable if the two scalars couple in a see-sawic fashion through a mass-degeneracy-driven unification

更新日期：2020-12-24
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-23
HongQiang Zhu, NaNa Ma, Yin Huang

Very recently, three new structures $$\Xi _c(2923)^0$$, $$\Xi _c(2938)^0$$, and $$\Xi _c(2964)^0$$ at the invariant mass spectrum of $$\Lambda _c^{+}K^{-}$$ observed by the LHCb Collaboration trigger a hot discussion about their inner structure. In this work, we study the strong decay mode of the newly observed $$\Xi ^0_c$$ assuming that the $$\Xi ^0_c$$ is a $$\bar{D}\Lambda -\bar{D}\Sigma$$ molecular

更新日期：2020-12-23
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-23
Shin-ichi Kawada, Jenny List, Mikael Berggren

The prospects for measuring the branching fraction of $$H \rightarrow \mu ^{+} \mu ^{-}$$ at the International Linear Collider (ILC) have been evaluated based on a full detector simulation of the International Large Detector (ILD) concept, considering centre-of-mass energies ($$\sqrt{s}$$) of 250 GeV and 500 GeV with two different beam polarisation configurations of \({\mathcal {P}} (e^{-}, e^{+})

更新日期：2020-12-23
• Eur. Phys. J. C (IF 4.389) Pub Date : 2020-12-23
Daniel Turgeman, Michael Pitt, Itamar Roth, Ehud Duchovni

Physics beyond the Standard Model (BSM) may be unveiled by studying events with a high number of outgoing jets, produced at the LHC with energies above the TeV scale (energetic multi-jet events). Such events are dominated by QCD processes, where the calculations rely on some sort of approximation. Therefore, it is important to develop a robust approach for modeling such events that could probe the

更新日期：2020-12-23
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