The European Physical Journal C最新文献

{"title":"Big Bang Nucleosynthesis constraints on the cosmological evolution in a Universe with a Weylian boundary","authors":"Teodora M. Matei,&nbsp;Cristian A. Croitoru,&nbsp;Tiberiu Harko","doi":"10.1140/epjc/s10052-025-14718-5","DOIUrl":"10.1140/epjc/s10052-025-14718-5","url":null,"abstract":"<div><p>We investigate the effects that arise from the inclusion of boundary terms in the Einstein gravitational field equations in the Big Bang Nucleosynthesis (BBN) framework. In particular, we consider the possibility that the boundary of the Universe is described by a Weyl type geometry. With the help of the generalized Friedmann equations for a Universe with a Weylian boundary, obtained for a Friedmann–Lemaitre–Robertson–Walker FLRW metric, three distinct cosmological models can be constructed. The cosmological evolution is determined by a dissipative scalar field, and by the Weyl vector coming from the boundary. Several cosmological scenarios are obtained via the appropriate splitting of the generalized energy conservation equation. In the present work we obtain relevant constraints on these models by using the BBN data. In particular, the effects on the BBN that arise in the post warm-inflationary era will be examined by theoretically evaluating the measured abundances of relic nuclei (Hydrogen, Deuterium, Helium-3, Helium-4, and Lithium-7). We consider firstly the primordial mass fraction estimates, and their deviations due to changes in the freezing temperature, which impose an upper limit on the effective energy density obtained from the modified Friedmann equations. The deviation from the standard energy density of the radiative plasma is therefore constrained by the abundances of the Helium-4 nuclei. Secondly, an upper limit will be considered in a numerical analysis performed through the usage of the <span>PRyMordial</span> software package, with the help of which we calculate the primordial abundances of the light elements by evaluating the thermonuclear rates within the considered modified gravity framework. Finally, an MCMC analysis will validate the cosmological model with Weylian boundary contributions, imposing relevant constraints on the initial conditions of the cosmos. The methodology is implemented in the python code <span>genesys</span>, which is available on GitHub.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14718-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210413","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":"Correction of Bekenstein–Hawking entropy of Kiselev black holes surrounded by quintessence owing to Lorentz breaking","authors":"Yu-zhen Liu,&nbsp;Cong Wang,&nbsp;Jie Zhang,&nbsp;Shu-Zheng Yang","doi":"10.1140/epjc/s10052-025-14747-0","DOIUrl":"10.1140/epjc/s10052-025-14747-0","url":null,"abstract":"<div><p>We consider a rotational symmetry solution for a Kiselev black hole that is wrapped in dark energy and defined by the equation of state. In the spacetime of the Kiselev black hole, considering Lorentz-breaking, the action of the scalar field is corrected, and the variational principle is applied to obtain the corrected scalar field equation in this black hole spacetime. The WKB approximation theory and black hole quantum tunneling radiation theory are applied to study the quantum tunneling rate, Hawking temperature, and entropy of the black hole, resulting in new expressions for the Hawking temperature and Bekenstein–Hawking entropy of the black hole. Finally, an in-depth discussion is presented on the employed research methods and obtained results.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14747-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145190264","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":"Unbinned inference with correlated events","authors":"Krish Desai,&nbsp;Owen Long,&nbsp;Benjamin Nachman","doi":"10.1140/epjc/s10052-025-14835-1","DOIUrl":"10.1140/epjc/s10052-025-14835-1","url":null,"abstract":"<div><p>Modern machine learning has enabled parameter inference from event-level data without the need to first summarize all events with a histogram. All of these unbinned inference methods make use of the fact that the events are statistically independent so that the log likelihood is a sum over events. However, this assumption is not valid for unbinned inference on unfolded data, where the deconvolution process induces a correlation between events. We explore the impact of event correlations on downstream inference tasks in the context of the OmniFold unbinned unfolding method. We find that uncertainties may be significantly underestimated when event correlations are excluded from uncertainty quantification.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14835-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210499","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":"Modeling HF-QPOs in microquasars and AGNs: charged particles around black holes with CDM halos","authors":"Z. Ahal,&nbsp;H. El Moumni,&nbsp;K. Masmar","doi":"10.1140/epjc/s10052-025-14830-6","DOIUrl":"10.1140/epjc/s10052-025-14830-6","url":null,"abstract":"<div><p>HF QPOs are among the most intriguing phenomena observed in LMXBs containing BHs or neutron stars. In this work, we investigate charged particles’ dynamics in the nearby of a Schwarzschild-like BH embedded in a uniform magnetic field and surrounded on all sides by CDM. Thereby gaining deeper insight into the influence of magnetic and DM distributions on observable phenomena near compact objects. We first present a modified metric, which incorporates the effects of a CDM, and we explore how both DM and magnetic fields influence the effective potential, stable circular orbits, and escape conditions for ionized particles. Employing a Hamiltonian formalism, we analyze the energy boundaries and ISCO, demonstrating that CDM causes an outward shift of the ISCO, while magnetic fields tend to pull it closer to the event horizon. We compute the fundamental oscillation frequencies – radial, latitudinal, Keplerian, and Larmor – and demonstrate how their variation depends on the combined influence of CDM and magnetic field strength. The resulting frequency structure allows us to identify resonance radii associated with HF QPOs, particularly those in 3:2 ratios observed in microquasars. We assess several theoretical models for QPO generation, including the Epicyclic Resonance (ER0, ER1, ER2, ER3, ER4, ER5), Relativistic Precession (RP0, RP1, RP2), Tidal Disruption (TD), and Warped Disk (WD) models. A comparative fit of observational data from GRS 1915+105, H1743-322, XTE 1550-564, and GRO 1655-40 demonstrates that the ER4 model provides the best match for HF QPOs in the presence of moderate magnetic flux <span>(B' = {-,0.01,,0,,0.01})</span>. In contrast, for supermassive black holes in some active galactic nuclei (AGNs), the model that best fits the majority of the data depends on the magnetic field strength: ER0 for <span>(B' = 0)</span>, and ER5 for <span>(B' = pm , 0.01)</span>. Our results highlight the importance of including both magnetic and dark matter (DM) effects in strong-field astrophysics and support the use of HF QPOs as sensitive probes of BH environments. This study opens new perspectives for exploring particle dynamics, accretion disk structure, and observational signatures of DM near compact objects.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14830-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210500","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":"Atmospheric muon flux suppression at potential new low-radiation Underground Physics Laboratory in Israel","authors":"Nadav Hargittai,&nbsp;Igor Zolkin,&nbsp;Yiftah Silver,&nbsp;Yan Benhammou,&nbsp;Gilad Mizrachi,&nbsp;Hagar Landsman,&nbsp;Erez Etzion,&nbsp;Ran Budnik","doi":"10.1140/epjc/s10052-025-14815-5","DOIUrl":"10.1140/epjc/s10052-025-14815-5","url":null,"abstract":"<div><p>The residual atmospheric muon flux was measured at a candidate site for a new underground, low-radiation physics laboratory beneath the <i>Kokhav HaYarden</i> national park in Israel. Located inside the tunnels of a hydroelectric pumped-storage facility, the proposed site benefits from a vertical rock overburden of 361 m, large potential floorspace, and easy access by road. A muon hodoscope of vertically stacked wide-area plastic scintillator plates was employed to measure the suppression in the integrated muon flux at the site as compared with above ground at sea level. The suppression factor is reported at <span>(4456 pm 77)</span>, expressed as <span>(3.75 pm 0.2 times 10^{-6})</span> <span>(text {cm}^{-2})</span> s<span>(^{-1})</span> in absolute terms, corresponding to an effective overburden of roughly 873 m.w.e.. Furthermore, the asymmetric topography of the mountain above and its muon shadow are clearly visible in the angular data. Finally, auxiliary environmental measurements recorded low background radon activity at <span>(28.3 pm 14.0)</span> Bq <span>(text {m}^{-3})</span>. The experimental campaign thus succeeded in demonstrating the viability of the site’s working conditions for future scientific research.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14815-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210937","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":"Probing Einstein–Maxwell-scalar black hole via thin accretion disks and shadows with EHT observations of M87* and Sgr A*","authors":"Yingdong Wu,&nbsp;Ziqiang Cai,&nbsp;Zhenglong Ban,&nbsp;Haiyuan Feng,&nbsp;Wei-Qiang Chen","doi":"10.1140/epjc/s10052-025-14831-5","DOIUrl":"10.1140/epjc/s10052-025-14831-5","url":null,"abstract":"<div><p>We investigated the shadows and thin accretion disks of Einstein–Maxwell-Scalar (EMS) black hole. Firstly, we investigated the influence of EMS parameters on the black hole shadow using the null geodesic method and constrained these parameters based on EHT observations of M87* and Sgr A*. Furthermore, we analyzed the direct emission, lensing ring, and photon ring structures in EMS black hole. Comparing our results with the Schwarzschild and Reissner–Nordstr<span>(ddot{textrm{o}})</span>m (RN) black holes, we found that the Schwarzschild black hole exhibits the largest shadow radius and the highest observed intensity.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14831-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210938","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":"Constraining the generalized Tolman–Oppenheimer–Volkoff (GTOV) equation with Bayesian analysis","authors":"Franciele M. da Silva,&nbsp;Fábio Köpp,&nbsp;Marcelo D. Alloy,&nbsp;Luis C. N. Santos,&nbsp;Adamu Issifu,&nbsp;Clésio E. Mota,&nbsp;Débora P. Menezes","doi":"10.1140/epjc/s10052-025-14784-9","DOIUrl":"10.1140/epjc/s10052-025-14784-9","url":null,"abstract":"<div><p>In this work, we constrain the values of the parameters of the Generalized Tolman–Oppenheimer–Volkoff (GTOV) equation through Bayesian inference. We use the mass and radius data from the Neutron Star Interior Composition Explorer (NICER) for PSR J0740<span>(+)</span>6620 and PSR J0030<span>(+)</span>0451, as well as the mass, radius, and dimensionless tidal deformability from the gravitational wave (GW) events GW190814 and GW170817. We use two distinct parameterizations of the extended non-linear Walecka model (eNLW) with and without hyperons. The GTOV employed for the study contains additional free parameters with different physical motivations. Two possible scenarios are considered in our analysis: conservative and speculative. In the first case, we take into account the most reliable neutron star (NS) data from NICER and the GW170817 event. In the second case, we consider the possibility that the compact object with a mass of <span>(2.54 M_{odot })</span> in the GW190814 event is an NS. Our findings show significant improvements in the physical quantities analyzed, leading to better agreement with the observational data compared to the results obtained using the TOV equation.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14784-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211034","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":"Black hole surrounded by perfect fluid dark matter in STV gravity: particle dynamics, thermodynamics, gravitational weak lensing and EHT tests","authors":"Sirojiddin Saydullayev,&nbsp;Isomiddin Nishonov,&nbsp;Muysin Dusaliyev,&nbsp;Obid Xoldorov,&nbsp;Sardor Murodov,&nbsp;Shavkat Karshiboev,&nbsp;Sunnatillo Urinov,&nbsp;Bekzod Rahmatov","doi":"10.1140/epjc/s10052-025-14780-z","DOIUrl":"10.1140/epjc/s10052-025-14780-z","url":null,"abstract":"<div><p>In this work, we explore the physical and observational properties of a static, spherically symmetric black hole solution in scalar–tensor–vector gravity (STVG), also known as modified gravity (MOG), in the presence of perfect fluid dark matter (PFDM). We analyze the motion of magnetized and neutral particles, focusing on the effective potential, innermost stable circular orbits (ISCO), and energy extraction efficiency via the Novikov–Thorne accretion model. Our results show that the MOG parameter <span>(alpha )</span> and the PFDM parameter <span>(lambda )</span> significantly influence the particle dynamics, stability conditions, and the efficiency of energy extraction. We also investigate thermodynamic quantities such as Hawking temperature, entropy, heat capacity, and Gibbs free energy, and find that PFDM and MOG parameters critically affect the black hole’s thermal stability and phase transitions. Additionally, we study gravitational lensing in uniform and non-uniform plasma environments and compute light deflection angles modified by both MOG and PFDM effects. Finally, we analyze the shadow cast by the black hole and compare it with Event Horizon Telescope (EHT) observations of M87* and Sgr A*, providing constraints on the MOG and PFDM parameters. Our results suggest that while general relativity remains a good approximation, small deviations due to modified gravity and surrounding dark matter effects cannot be ruled out.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14780-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210936","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":"Impact of embedded (^{163})Ho on the performance of the transition-edge sensor microcalorimeters of the HOLMES experiment","authors":"Douglas Bennett,&nbsp;Matteo Borghesi,&nbsp;Pietro Campana,&nbsp;Rodolfo Carobene,&nbsp;Giancarlo Ceruti,&nbsp;Matteo De Gerone,&nbsp;Marco Faverzani,&nbsp;Lorenzo Ferrari Barusso,&nbsp;Elena Ferri,&nbsp;Joseph Fowler,&nbsp;Sara Gamba,&nbsp;Flavio Gatti,&nbsp;Andrea Giachero,&nbsp;Marco Gobbo,&nbsp;Danilo Labranca,&nbsp;Roberto Moretti,&nbsp;Angelo Nucciotti,&nbsp;Luca Origo,&nbsp;Stefano Ragazzi,&nbsp;Dan Schmidt,&nbsp;Daniel Swetz,&nbsp;Joel Ullom","doi":"10.1140/epjc/s10052-025-14814-6","DOIUrl":"10.1140/epjc/s10052-025-14814-6","url":null,"abstract":"<div><p>We present a detailed investigation of the performance of transition-edge sensor (TES) microcalorimeters with <span>(^{163})</span>Ho atoms embedded by ion implantation, as part of the HOLMES experiment aimed at neutrino mass determination. The inclusion of <span>(^{163})</span>Ho atoms introduces an excess heat capacity due to a pronounced Schottky anomaly, which can affect the detector’s energy resolution, signal height, and response time. We fabricated TES arrays with varying levels of <span>(^{163})</span>Ho activity and characterized their performance in terms of energy resolution, decay time constants, and heat capacity. The intrinsic energy resolution was found to degrade with increasing <span>(^{163})</span>Ho activity, consistent with the expected scaling of heat capacity. From the analysis, we determined the specific heat capacity of <span>(^{163})</span>Ho to be <span>((2.9 pm 0.4 mathrm {(stat)} pm 0.7 mathrm {(sys)}))</span> J/K/mol at <span>((94 pm 1))</span> mK, close to the literature values for metallic holmium. No additional long decay time constants correlated with <span>(^{163})</span>Ho activity were observed, indicating that the excess heat capacity does not introduce weakly coupled thermodynamic systems. These results suggest that our present TES microcalorimeters can tolerate <span>(^{163})</span>Ho activities up to approximately 5 Bq, with only about a factor of three degradation in performance compared to detectors without <span>(^{163})</span>Ho. For higher activities, reducing the TES transition temperature is necessary to maintain or improve the energy resolution. These findings provide critical insights for optimizing TES microcalorimeters for future neutrino mass experiments and other applications requiring embedded radioactive sources. The study also highlights the robustness of TES technology in handling limited amounts of implanted radionuclides while maintaining high-resolution performance.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14814-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210935","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":"Strings with a different tension producing dark copies of the Standard Model","authors":"E. I. Guendelman","doi":"10.1140/epjc/s10052-025-14777-8","DOIUrl":"10.1140/epjc/s10052-025-14777-8","url":null,"abstract":"<div><p>This is a comment on our previous paper (Guendelman in Eur Phys J C 85(6). https://doi.org/10.1140/epjc/s10052-025-14408-2). The string and brane tensions do not have to be put in by hand, they can be dynamically generated, as in the case when we formulate string and brane theories in the modified measure formalism. Then string tension appears, but as an integration constant. It can be seen however that these string tensions are not universal, but rather each string and each brane generates its own tension. To make the string tension fully dynamical, a bulk field (the tension field) is introduced. As we have seen in previous publications, world sheet conformal invariance in the case of two different species of strings with different tension can produce braneworlds. Now we add another crucial observation; dark matter to us may consist of matter made out of strings with different tensions because of decoupling of standard string interactions for strings with different tensions, although interactions mediated by the tension field can exist between strings of different tensions. Furthermore, Visible Matter strings and these “dark strings” share the same space time, and therefore the same compactifications, etc. Since the choice of compactification organizes the structure of the theory including its particle content, we expect therefore that the dark sector will consist of dark copies of the standard model and a visible Matter Dark Matter correspondence could be established.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14777-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210967","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}