The European Physical Journal C最新文献

{"title":"Beyond comoving volume: horizon flux and matter creation in modified cosmology from the unified first law of thermodynamics","authors":"Víctor H. Cárdenas,&nbsp;Miguel Cruz,&nbsp;Samuel Lepe","doi":"10.1140/epjc/s10052-026-16334-3","DOIUrl":"10.1140/epjc/s10052-026-16334-3","url":null,"abstract":"<div><p>We explore the derivation of the Friedmann equations from a thermodynamic perspective, applying the unified first law of thermodynamics to the apparent horizon of a flat Friedmann–Lemaître–Robertson–Walker (FLRW) universe. We extend this framework to incorporate gravitationally induced particle creation, treating the region enclosed by the apparent horizon as an open thermodynamic system. A crucial aspect of our analysis is the recognition that the apparent horizon volume is not comoving; this requires consistent accounting of particle exchange across the moving boundary. We demonstrate that the evolution of the particle number, and explicitly the matter entropy, can be decomposed into two distinct physical contributions: genuine bulk particle production and a net flux induced by the dynamics of the horizon itself. Finally, we derive the Generalized Second Law (GSL) in this setting, showing transparently how the total entropy budget is balanced by horizon thermodynamics, bulk creation, and boundary fluxes.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16334-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Worldline images for Yang–Mills theory within boundaries","authors":"Santiago Christiansen Murguizur,&nbsp;Lucas Manzo,&nbsp;Pablo Pisani","doi":"10.1140/epjc/s10052-026-16273-z","DOIUrl":"10.1140/epjc/s10052-026-16273-z","url":null,"abstract":"<div><p>In this article we develop a worldline technique based on the method of images to study the effective action associated to Yang–Mills theories on manifolds with boundaries. We consider the possibility of having either relative or absolute boundary conditions, which are particular types of mixed boundary conditions. Both vector fields and ghost fields are taken into account in this analysis. As a check of our construction, we compute the first three Seeley–DeWitt coefficients of the heat kernel asymptotics. Finally, we employ our technique to calculate the rate of gluon production due to a chromoelectric field background in the presence of a boundary.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16273-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dyonic rotating cosmological black hole surrounded by quintessence","authors":"M. D. de Oliveira,&nbsp;Alexandre G. M. Schmidt","doi":"10.1140/epjc/s10052-026-16309-4","DOIUrl":"10.1140/epjc/s10052-026-16309-4","url":null,"abstract":"<div><p>In this work, we constructed a new metric describing a rotating cosmological black hole with electric and magnetic charges in the presence of quintessence dark energy, where the cosmological constant and quintessence are associated with external matter. Starting from a Ç-ççtype metric and considering all energy contributions in the function <i>f</i>(<i>r</i>),  we introduced rotation through the Newman–Janis algorithm using a unique and general complexification rule, avoiding possible ambiguities. Assuming that the metric satisfies the Einstein field equations with matter, we calculate the event horizon condition, the total stress–energy tensor <span>(T_{mu nu },)</span> and the Kretschmann and Ricci scalars. We also analyze the influence of the cosmological constant <span>(Lambda )</span> and quintessence parameter <span>(alpha )</span> on the event horizon and ergosphere. In the limit <span>(alpha rightarrow 0,)</span> the scalar curvature differs from the vacuum result, <span>(R ne -4Lambda ,)</span> while the singularity region remains unchanged. Finally, we investigate the angular and rotational velocities of a test particle, as well as the energy conditions, through the energy density and pressures required for the existence of this black hole solution.\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16309-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unimodular gravity with arbitrary diffusion function: a dynamical system reconstruction approach","authors":"Gabriel Gómez,&nbsp;Guillermo Palma,&nbsp;Norman Cruz","doi":"10.1140/epjc/s10052-026-16363-y","DOIUrl":"10.1140/epjc/s10052-026-16363-y","url":null,"abstract":"<div><p>We investigate cosmological diffusion models in unimodular gravity within a dynamical systems reconstruction framework. By treating the logarithmic slope of the diffusion sector as an invertible dynamical variable, the diffusion function can be systematically reconstructed from the phase-space structure of the cosmological evolution. Under these conditions, we determine the physically admissible fixed points of the system, identifying novel matter–diffusion scaling solutions associated with power-law diffusion sectors, as well as purely diffusion-dominated configurations capable of driving late-time accelerated expansion without requiring an explicit cosmological constant term. The local behavior around the fixed points is then extended to the full cosmological evolution, providing a framework to explore the global implications of diffusion cosmologies. Beyond the asymptotic fixed-point structure, we further develop a reconstruction formalism based on the dynamical evolution of the diffusion slope, allowing for trajectories interpolating between different diffusion regimes during the cosmic history. Our results establish a systematic framework for constructing and classifying viable diffusion cosmologies in unimodular gravity directly from the phase-space dynamics.\u0000\u0000\u0000\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16363-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studying the tensor resonance contributions in (B rightarrow PPell ^+ell ^-) and (B rightarrow PVell ^+ell ^-) decays","authors":"Ru-Min Wang,&nbsp;Xiu-Ping Fan,&nbsp;Si-Yu Xu,&nbsp;Yi Qiao,&nbsp;Xiao-Dong Cheng,&nbsp;Yuan-Guo Xu","doi":"10.1140/epjc/s10052-026-16341-4","DOIUrl":"10.1140/epjc/s10052-026-16341-4","url":null,"abstract":"<div><p>We analyze the semileptonic <span>(B rightarrow Tell ^+ell ^-)</span>, <span>(B rightarrow T(rightarrow PP)ell ^+ell ^-)</span>, and <span>(B rightarrow T(rightarrow PV)ell ^+ell ^-)</span> decays with <span>(ell =e,mu ,tau )</span> based on flavor SU(3) analysis in the standard model (<i>T</i> denotes the light tensor meson, <i>P</i> denotes the light pseudoscalar meson, and <i>V</i> denotes the light vector meson). The hadronic amplitudes of the <span>(B rightarrow Tell ^+ell ^-)</span> decays are related by the nonperturbative parameters, and all branching ratios of the <span>(B rightarrow Tell ^+ell ^-)</span> decays are obtained by the experimental data of the branching ratio of <span>(B^0_srightarrow f^{prime }_{2}(1525)mu ^+mu ^-)</span> in three cases, and then the branching ratios of the <span>(B rightarrow T(rightarrow PP)ell ^+ell ^-)</span> and <span>(B rightarrow T(rightarrow PV)ell ^+ell ^-)</span> decays are predicted by the narrow width approximation and further considering finite width effects of the intermediate resonances. Compared with the narrow width results, the finite width effects slightly reduce the branching fractions for most decays. However, sizeable finite width effects are found in some near threshold modes. For the subthreshold <span>(K_2^*(1430)rightarrow Keta ')</span> relevant channels, the finite width of the tensor resonance can open a nonzero contribution. Compared with the measured <span>(B rightarrow PPell ^+ell ^-)</span> and <span>(B rightarrow PVell ^+ell ^-)</span> decays, we find that the branching ratios with the tensor resonance states are small. Therefore, other resonances, for example, the vector mesons, the scalar mesons, the axial-vector mesons or their excited states, might give the dominant contributions to the relevant decays. Our results might be tested in current and future experiments.\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16341-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements of the production of W(^{pm }) and Z(^0) bosons in pp collisions at (sqrt{s} = 13) TeV","authors":"ALICE Collaboration","doi":"10.1140/epjc/s10052-026-15943-2","DOIUrl":"10.1140/epjc/s10052-026-15943-2","url":null,"abstract":"<div><p>Measurements of the production of the W<span>(^{pm })</span> and Z<span>(^0)</span> bosons at midrapidity in pp collisions at <span>(sqrt{s} = 13)</span> TeV with ALICE at the Large Hadron Collider (LHC) are presented. The W<span>(^{pm })</span> and Z<span>(^0)</span> bosons are detected via their (di)electronic decay channels, with the electron reconstruction performed in the midrapidity region <span>((|y|&lt; 0.6).)</span> The <span>(p_{{text {T}}})</span>-integrated and <span>(p_{textrm{T}})</span>-differential production cross sections of electrons from W<span>(^{pm })</span> decays in the interval <span>(30&lt;p_{{text {T}}}&lt; 60)</span> GeV/<i>c</i>,  as well as the <span>(p_{{text {T}}})</span>-integrated production cross section of Z<span>(^0)</span> bosons, are measured. The results are described by perturbative QCD calculations using different sets of parton distribution functions. The production of W<span>(^{pm })</span> bosons and azimuthally correlated associated hadrons is also measured as a function of the charged-particle multiplicity for the first time at the LHC. The former increases approximately linearly with the charged-particle multiplicity, while for the latter, there are hints of a faster-than-linear increase. These observations are compared with theoretical calculations\u0000.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15943-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On recent measurements of toponium threshold enhancement in entire-function-regulated nonlocal quantum field theory","authors":"E. J. Thompson","doi":"10.1140/epjc/s10052-026-16177-y","DOIUrl":"10.1140/epjc/s10052-026-16177-y","url":null,"abstract":"<div><p>The recent (not so recent now) data from the LHC has a reported threshold enhancement in top-antitop production, we want to present a reinterpretation of the the recently published data. We do this in nonlocal quantum field theory and we show that the observed threshold excess can be made to fit by a data-driven nonlocal scale <span>(Lambda _{textrm{ker}})</span> and small RG effects, while keeping global QCD tests intact. We then contrast the properties of the heavyquark systems highlighting the unique role of the top quark’s decay width in shaping the phenomenology of toponium. We find that toponium becomes a powerful tool for both infrared boundstate dynamics and ultraviolet completion effects opening new avenues for precision tests of QCD.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16177-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equilibrium halo solutions of the Gross–Pitaevskii–Poisson system: the role of the particle number","authors":"Francisco A. Guzmán,&nbsp;Elías Castellanos,&nbsp;Jorge Mastache","doi":"10.1140/epjc/s10052-026-16373-w","DOIUrl":"10.1140/epjc/s10052-026-16373-w","url":null,"abstract":"<div><p>We investigate stationary halo-like solutions of the Gross–Pitaevskii–Poisson (GPP) system, which describes self-gravitating Bose–Einstein condensates with repulsive self-interactions, as a model for dark matter. We retain the boson mass <span>(m_phi )</span>, the scattering length <span>(a_s)</span>, and the total particle number <i>N</i> explicitly, treating the latter as an independent macroscopic control parameter of the equilibrium configuration. We solve the stationary GPP equations and explore a broad region of parameter space. The resulting equilibrium configurations are classified into ground-state, excited-state, and unbound branches according to their binding properties and nodal structure. We find that the ground-state branch occupies a well-defined region of the <span>((m_phi ,N))</span> plane whose location is highly sensitive to the self-interaction strength, whereas the excited-state and unbound regions exhibit a structure largely independent of the initial ansatz. By analyzing the converged solutions, we derive empirical scaling relations linking the characteristic halo radius <span>(R_{99})</span> to the boson mass, scattering length, and total particle number. The recovered scaling reproduces the known mass–radius relation in the non-interacting limit, while finite self-interactions reveal an intermediate regime in which gravity, quantum pressure, and repulsive interactions jointly determine the equilibrium structure, deviating from the asymptotic Thomas–Fermi limit. As an astrophysical application, we show that ground-state solutions can reproduce the rotation curves of representative dwarf galaxies using only the solitonic component. Finally, we examine the impact of repulsive self-interactions on the location of the ground-state branch and discuss the implications for current Lyman-<span>(alpha )</span> forest constraints. Although increasing <span>(a_s)</span> shifts equilibrium solutions toward boson masses compatible with existing Lyman-<span>(alpha )</span> bounds, the corresponding halo configurations fail to reproduce the observed dwarf-galaxy kinematics. Our results provide a systematic characterization of stationary GPP halos and establish a direct connection among the fundamental particle properties <span>((m_phi , a_s))</span>, the macroscopic control parameter <i>N</i>, and observable galactic properties.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16373-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of spurious-electron signals in the double-phase argon TPC of the DarkSide-50 experiment","authors":"DarkSide-50 Collaboration","doi":"10.1140/epjc/s10052-026-16193-y","DOIUrl":"10.1140/epjc/s10052-026-16193-y","url":null,"abstract":"<div><p>Spurious-electron signals in dual-phase noble-liquid time projection chambers have been observed in both xenon and argon Time Projection Chambers (TPCs). This paper presents the first comprehensive study of spurious electrons in argon, using data collected by the DarkSide-50 experiment at the INFN Laboratori Nazionali del Gran Sasso (LNGS). Understanding these events is a key factor in improving the sensitivity of low-mass dark matter searches exploiting ionization signals in dual-phase noble liquid TPCs. We find that a significant fraction of spurious-electron events, ranging from 30 to 70% across the experiment’s lifetime, are caused by electrons captured from impurities and later released with delay time constants on the orders of 5 ms and 50 ms. The rate of spurious-electron events is found to correlate with the operational condition of the purification system and the total event rate in the detector. Finally, we present evidence that multi-electron spurious electron events may originate from photo-ionization of the steel grid used to define the electric fields. These observations indicate the possibility of reduction of the background in future experiments and hint at possible spurious electron production mechanisms. \u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16193-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gravitational wave signatures and periodic orbits of a charged black hole in a Hernquist dark matter halo","authors":"N. Heidari,&nbsp;A. A. Araújo Filho,&nbsp;Iarley P. Lobo","doi":"10.1140/epjc/s10052-026-16322-7","DOIUrl":"10.1140/epjc/s10052-026-16322-7","url":null,"abstract":"<div><p>In this work, we study the motion of massive test particles and the gravitational wave emission associated with periodic trajectories around a magnetically charged black hole immersed in a <i>Hernquist</i> dark matter halo. We begin by analyzing the effective potential and the conditions for stable motion, with particular attention to the marginally bound radius and the innermost stable circular orbit. Our results show that the dark matter parameters, namely the halo density and scale radius, enlarge the allowed region and generally shift the relevant characteristic radii and angular momenta toward larger values. In contrast, the magnetic charge partially counterbalances this behavior. We then examine periodic trajectories through the rational number <i>q</i>,  which characterizes the relation between the azimuthal and radial frequencies, and construct representative zoom–whirl configurations together with their precessing counterparts. Finally, we investigate the imprints of dark matter and magnetic monopole charge on the gravitational wave polarizations in the extreme mass–ratio regime. To explore the observational relevance of the predicted gravitational wave signals, we compute their characteristic strains in the frequency domain and compare them with the LISA sensitivity curve.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 9","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16322-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149034793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}