Astroparticle Physics最新文献

{"title":"Reconstruction of inclined extensive air showers using radio signals: From arrival times and amplitudes to direction and energy","authors":"Marion Guelfand ,&nbsp;Valentin Decoene ,&nbsp;Olivier Martineau-Huynh ,&nbsp;Simon Prunet ,&nbsp;Matías Tueros ,&nbsp;Oscar Macias ,&nbsp;Aurélien Benoit-Lévy","doi":"10.1016/j.astropartphys.2025.103120","DOIUrl":"10.1016/j.astropartphys.2025.103120","url":null,"abstract":"<div><div>Radio detection is now an established technique for the study of ultra-high-energy (UHE) cosmic rays with energies above <span><math><mrow><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>17</mn></mrow></msup></mrow></math></span> <!--> <!-->eV. The next-generation of radio experiments aims to extend this technique to the observation of UHE earth-skimming neutrinos, which requires the detection of very inclined extensive air showers (EAS). In this article we present a new reconstruction method for the arrival direction and the energy of EAS. It combines a point-source-like description of the radio wavefront with a phenomenological model: the Angular Distribution Function (ADF). The ADF describes the angular distribution of the radio signal amplitude in the 50–200<!--> <!-->MHz frequency range, with a particular focus on the Cherenkov angle, a crucial feature of the radio amplitude pattern. The method is applicable to showers with zenith angles larger than <span><math><mrow><mn>60</mn><mo>°</mo></mrow></math></span>, and in principle up to neutrino-induced showers with up-going trajectories. It is tested here on a simulated data set of EAS induced by cosmic rays. A resolution better than 4 arc-minutes (<span><math><mrow><mn>0</mn><mo>.</mo><mn>07</mn><mo>°</mo></mrow></math></span>) is achieved on arrival direction, as well as an intrinsic resolution of 5% on the electromagnetic energy, and around 15% on the primary energy.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"171 ","pages":"Article 103120"},"PeriodicalIF":4.2,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144115553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of singly-charged particles identification with the AMS02 RICH detector by a machine learning method","authors":"Georgi Vasilev,&nbsp;Galina Vankova-Kirilova,&nbsp;Galina Bozhkova","doi":"10.1016/j.astropartphys.2025.103134","DOIUrl":"10.1016/j.astropartphys.2025.103134","url":null,"abstract":"<div><div>AMS-02 is a detector currently in operation onboard the International Space Station (ISS). One of the main scientific goals of the spectrometer is the measurement of charged particle fluxes. The detector design makes possible the identification of particles and antiparticles by precise measurement of particle momentum in the AMS-02 Silicon Tracker, and velocity in the Cherenkov (RICH) detector. The RICH is able to measure the isotopic composition of the light elements (up to charge <em>Z</em> = 5) in the kinetic energy range from a few GeV/n to about 10 GeV/n. However, the velocity reconstruction for charge 1 particles is particularly challenging due to the low number of photons they produce in the RICH detector which can lead to wrong event reconstruction. In this paper, we show the high potential of the Multilayer Perceptron deep learning model (MLP-BFGS) for identification of signal and the background due to interactions inside the AMS-02 detector, and to significantly improve particle identification by its mass.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"171 ","pages":"Article 103134"},"PeriodicalIF":4.2,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Axionic quantum fluctuations, dark energy, and the Hubble tension” [Volume 169, July 2025, 103111 Astroparticle Physics]","authors":"L. Acedo","doi":"10.1016/j.astropartphys.2025.103121","DOIUrl":"10.1016/j.astropartphys.2025.103121","url":null,"abstract":"","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"171 ","pages":"Article 103121"},"PeriodicalIF":4.2,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization and absolute calibration of R11265 multi-anode photomultiplier tubes for the JEM-EUSO space and balloon program, I: Methods and generic features","authors":"E. Parizot ,&nbsp;D. Trofimov ,&nbsp;S. Blin ,&nbsp;A. Creusot ,&nbsp;D. Allard ,&nbsp;B. Baret ,&nbsp;P. Barrillon ,&nbsp;M. Battisti ,&nbsp;A.A. Belov ,&nbsp;C. Blaksley ,&nbsp;P. Gorodetzky ,&nbsp;P.A. Klimov ,&nbsp;E. Msihid ,&nbsp;L. Piotrowski ,&nbsp;G. Prévôt ,&nbsp;J. Szabelski ,&nbsp;C. de la Taille","doi":"10.1016/j.astropartphys.2025.103112","DOIUrl":"10.1016/j.astropartphys.2025.103112","url":null,"abstract":"<div><div>Over the last decade, the Joint Exploratory Missions for an Extreme Universe Space Observatory (JEM-EUSO) collaboration has developed several balloon and space missions implementing different versions of a dedicated camera based on multi-anode photomultiplier tubes (MAPMTs) used in single photoelectron counting mode, in the near ultra-violet. In this paper, we present the experimental techniques developed to calibrate these MAPMTs and determine their main characteristics, relevant to the JEM-EUSO applications. Our results include the absolute calibration of the MAPMTs in both full illumination and localized illumination modes, the measurement of the so-called s-curves and their fitting with a newly developed fitting formula, the study of cross-talk and residual non-Poissonian behaviour, the determination of the physical size of the individual pixels, the wavelength dependence of the photodetection efficiency, the characterization of the pile-up effect and the determination of the corresponding double pulse resolution using a dedicated readout implementing the SPACIROC-3 Application-specific integrated circuit. These techniques allowed us to identify generic features of the MAPMTs of type R11265 from Hamamatsu, including the occasional occurrence of multiple counting of single photons, which the Hamamatsu company was then able to correct and eliminate. We find that the reliability, high-efficiency and homogeneity of these MAPMTs is well suited for the multi-disciplinary scientific objectives of the JEM-EUSO collaboration. The application of our techniques to the characterization and absolute calibration of the fluorescence camera of the EUSO-SPB2 mission is presented in an accompanying paper.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"171 ","pages":"Article 103112"},"PeriodicalIF":4.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Axionic quantum fluctuations, dark energy, and the Hubble tension","authors":"L. Acedo","doi":"10.1016/j.astropartphys.2025.103111","DOIUrl":"10.1016/j.astropartphys.2025.103111","url":null,"abstract":"<div><div>The cosmological constant is now a fundamental ingredient of the standard ΛCDM model, and its value is constrained by concordance with empirical data. Despite its importance in modern cosmology, we still do not understand its origin. A naive calculation of the contribution of the quantum vacuum fluctuations to vacuum energy (considering it to be the source of the cosmological constant) yields predictions 120 orders of magnitude larger than observations. This poses one of the most celebrated unsolved problems in physics and cosmology. This work discusses a model of quantum-thermal fluctuations of the cosmic microwave background with a Planck factor. Fluctuations of a bosonic field are studied, and we show that they could match the vacuum energy density if they correspond to an axionic field with a particle rest mass in the range of a fraction of a meV. This mass range is in agreement with present bounds on the mass of the Peccei–Quinn axions arising from the spontaneous symmetry breaking that explains CP conservation in strong interactions, as well as estimations of the mass of axions in the galactic halo and experiments on Shapiro step anomalies using Josephson junctions. We also show that this model can clarify the Hubble tension debate, i.e., the statistically significant discrepancy between measurements of the Hubble parameter based upon the cosmic microwave background and those using low redshift observations.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"169 ","pages":"Article 103111"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond the local Universe: Impacts of scalar field coupled to non-relativistic neutrinos on bulk flow","authors":"Muhammad Yarahmadi","doi":"10.1016/j.astropartphys.2025.103110","DOIUrl":"10.1016/j.astropartphys.2025.103110","url":null,"abstract":"<div><div>This study explores the role of neutrinos in the Universe’s expansion history, tracing their transition from a relativistic phase in the early Universe to non-relativistic massive particles at later epochs. Within the framework of neutrino coupling with a scalar field, we examine cosmic evolution from radiation domination to dark energy dominance. By analyzing combined datasets (Pantheon+, Cosmic Microwave Background, Baryon Acoustic Oscillations, Cosmic Chronometers, and CMB lensing), we constrain the total neutrino mass to <span><math><mrow><mo>∑</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>ν</mi></mrow></msub><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>105</mn><mspace></mspace><mi>eV</mi></mrow></math></span> (95% CL). The transition redshifts <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>nr</mi></mrow></msub></math></span> range from 76 to 205, marking the onset of matter domination. The coupling parameter is constrained to <span><math><mrow><mi>α</mi><mo>=</mo><mn>5</mn><mo>.</mo><mn>64</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>1</mn></mrow></math></span>, consistent with growing neutrino quintessence, reinforcing the role of neutrinos despite their small mass. Late-time evolution analyses, comparing scenarios with and without neutrino coupling, reveal that non-relativistic neutrinos contribute to cosmic anisotropy. At low redshifts (<span><math><mrow><mn>0</mn><mo>.</mo><mn>001</mn><mo>&lt;</mo><mi>z</mi><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>1</mn></mrow></math></span>), the bulk flow direction aligns with the CMB dipole, while at higher redshifts, it correlates with the dark energy dipole. The evolution of neutrino density-to-redshift ratios suggests that a decreasing neutrino density weakens gravitational influence, leading to an increase in bulk velocity within <span><math><mrow><mn>0</mn><mo>.</mo><mn>1</mn><mo>&lt;</mo><mi>z</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span> and a decline within <span><math><mrow><mn>1</mn><mo>&lt;</mo><mi>z</mi><mo>&lt;</mo><mn>1</mn><mo>.</mo><mn>4</mn></mrow></math></span>. These findings highlight the role of non-relativistic neutrinos in shaping cosmic anisotropy and dark energy dynamics, offering new perspectives on the Universe’s large-scale evolution.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"169 ","pages":"Article 103110"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of a fiber laser hydrophone for acoustic neutrino detection","authors":"E.J. Buis ,&nbsp;A.M. von Benda-Beckmann ,&nbsp;E. Doppenberg ,&nbsp;J. Dorant ,&nbsp;T.H. Jansen ,&nbsp;P. Toet ,&nbsp;P. Verhooren ,&nbsp;J. de Vreugd","doi":"10.1016/j.astropartphys.2025.103109","DOIUrl":"10.1016/j.astropartphys.2025.103109","url":null,"abstract":"<div><div>This paper presents the development and characterization of a fiber laser hydrophone designed for deep-sea applications, with a focus on detecting neutrino interactions via their acoustic signatures. The hydrophone design includes a static pressure compensation mechanism, ensuring reliable operation at depths exceeding 1 km. The performance of the hydrophone was evaluated through laboratory tests and experiments in an anechoic basin, where its transfer function was measured before and after a 140-bar pressure cycle. The results show that the hydrophone maintains its sensitivity, with resonance peaks identified in both low- and high-frequency ranges. The hydrophone’s sensitivity to acoustic signals was also compared to ambient sea state noise levels, demonstrating compatibility with the lowest noise conditions.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"170 ","pages":"Article 103109"},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"I-C-Q relations for rapidly rotating stable hybrid stars","authors":"Sujan Kumar Roy,&nbsp;Gargi Chaudhuri","doi":"10.1016/j.astropartphys.2025.103108","DOIUrl":"10.1016/j.astropartphys.2025.103108","url":null,"abstract":"<div><div>A number of hadronic equations of state for neutron stars have been investigated for the purpose of the present paper, considering the fact that at sufficiently high density, heavy baryons and quark phases may appear. The observational limits from NICER, GW170817, etc., are obeyed by our choice of equations of state. The universal relations are investigated for both slowly and rapidly rotating neutron stars with heavy baryons present inside the core. For slowly rotating stars, the universality of the I-Love-Q relations is verified, and the I-C-Q relations are inferred to be universal for rapidly rotating stars. Further, we extend the investigation to obtain the universal relations for compact stars containing the quark core, where the connected stable branch of such hybrid stars is considered. The parameters of the I-Love-Q and I-C-Q universal relations are obtained for slowly rotating and rapidly rotating hybrid stars, respectively. These relations would enable extracting information, within the context of general relativity, from astrophysical systems involving rapidly rotating neutron stars.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"170 ","pages":"Article 103108"},"PeriodicalIF":4.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of cosmic muon-induced neutron background with ISMRAN detector in a non-reactor environment","authors":"R. Dey ,&nbsp;P.K. Netrakanti ,&nbsp;D.K. Mishra ,&nbsp;S.P. Behera ,&nbsp;R. Sehgal ,&nbsp;V. Jha ,&nbsp;L.M. Pant","doi":"10.1016/j.astropartphys.2025.103101","DOIUrl":"10.1016/j.astropartphys.2025.103101","url":null,"abstract":"<div><div>The Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN) is an above-ground, very short baseline reactor anti-neutrino (<span><math><msub><mrow><mover><mrow><mi>ν</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>e</mi></mrow></msub></math></span>) experiment, located inside the Dhruva research reactor facility, Mumbai, India. The primary goal of the ISMRAN experiment is the indirect detection of reactor <span><math><msub><mrow><mover><mrow><mi>ν</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>e</mi></mrow></msub></math></span> through an inverse beta decay (IBD) process, using a cluster of 90 optically segmented plastic scintillator detectors, weighing <span><math><mo>∼</mo></math></span>1 ton. However, the most difficult to distinguish correlated background for the ISMRAN experiment is from fast neutrons, which cannot be actively rejected and as a consequence mimics the IBD process through proton recoil inside the detector’s volume. In this work, we present the neutron capture time response and energy deposition of neutron capture signals generated by cosmic muons in the ISMRAN geometry, and we compare these experimental results with Geant4-based Monte Carlo (MC) simulations. The obtained mean capture time of fast neutrons is 74.46 <span><math><mo>±</mo></math></span> 5.98 <span><math><mi>μ</mi></math></span>s and is comparable with the MC simulation results. The efficiency-corrected rate of muon-induced neutron background inside the ISMRAN geometry, due to the presence of a passive shielding structure of 10 cm lead followed by 10 cm borated polyethylene with a surface area of 600 cm², deployed on top of the ISMRAN setup, is reported to be 1334 ± 64 (stat.) <span><math><mo>±</mo></math></span> 70 (sys.) per day. This result shows good agreement with the expected background rate from MC simulations using Geant4. Additionally, we also estimate the muon-induced fast-neutron rate in the ISMRAN geometry for the actual shielding configuration of 9000 cm² surface area to be 3335 ± 160 (stat.) <span><math><mo>±</mo></math></span> 175 (sys.) neutrons day^-1 through an extrapolation, after incorporating the model dependent acceptance correction factor from the Geant4 MC simulation. Finally, using these results, we evaluate the neutron production yield due to the composite shielding in the ISMRAN geometry, which is 2.81<span><math><mo>×</mo></math></span> 10^-5 neutrons per <span><math><mi>μ</mi></math></span> per (g/cm²) at sea level. These results will be significant in the context of differentiating correlated background from true <span><math><msub><mrow><mover><mrow><mi>ν</mi></mrow><mo>¯</mo></mover></mrow><mrow><mi>e</mi></mrow></msub></math></span> events at the actual measurement site inside the reactor facility.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"169 ","pages":"Article 103101"},"PeriodicalIF":4.2,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shadows and optical appearances of black holes in R2 gravity","authors":"Khadije Jafarzade ,&nbsp;Sanjar Shaymatov ,&nbsp;Mubasher Jamil","doi":"10.1016/j.astropartphys.2025.103100","DOIUrl":"10.1016/j.astropartphys.2025.103100","url":null,"abstract":"<div><div>In this paper, we consider a charged AdS/dS black hole (BH) in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> gravity and study its optical features, including the shadow’s geometrical shape and the energy emission rate. Additionally, we look for criteria to restrict the free parameters of the theory by comparing them to observational data of M87<span><math><msup><mrow></mrow><mrow><mo>⋆</mo></mrow></msup></math></span>. Then, we employ the Newman-Janis algorithm to build the rotating counterpart of the static solution in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> gravity and calculate the energy emission rate for the rotating case as well as discuss how the rotation factor and other parameters of this theory affect the emission of particles around the BHs. In the following, we consider the obtained rotating BH as a supermassive black hole and evaluate the parameters of the model with shadow size estimates based on the observations of M87<span><math><msup><mrow></mrow><mrow><mo>⋆</mo></mrow></msup></math></span> from EHT.</div></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"168 ","pages":"Article 103100"},"PeriodicalIF":4.2,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}