ABSTRACT
The existence of high-energy astrophysical neutrinos has been unambiguously demonstrated, but their sources remain elusive. IceCube reported an association of a 290-TeV neutrino with a ...gamma-ray flare of TXS 0506 + 056, an active galactic nucleus with a compact radio jet pointing to us. Later, radio-bright blazars were shown to be associated with IceCube neutrino events with high statistical significance. These associations remained unconfirmed with the data of independent experiments. Here, we report on the detection of a rare neutrino event with the estimated energy of 224 ± 75 TeV from the direction of TXS 0506 + 056 by the new Baikal Gigaton Volume Detector (Baikal-GVD) in April 2021. This event is the highest energy cascade detected so far by the Baikal-GVD neutrino telescope from a direction below horizon. The result supports previous suggestions that radio blazars in general, and TXS 0506 + 056 in particular, are the sources of high-energy neutrinos, and opens up the cascade channel for the neutrino astronomy.
ABSTRACT
Baikal-GVD has recently published its first measurement of the diffuse astrophysical neutrino flux, performed using high-energy cascade-like events. We further explore the Baikal-GVD cascade ...data set collected in 2018–2022, with the aim to identify possible associations between the Baikal-GVD neutrinos and known astrophysical sources. We leverage the relatively high angular resolution of the Baikal-GVD neutrino telescope (2–3 deg.), made possible by the use of liquid water as the detection medium, enabling the study of astrophysical point sources even with cascade events. We estimate the telescope’s sensitivity in the cascade channel for high-energy astrophysical sources and refine our analysis prescriptions using Monte-Carlo simulations. We primarily focus on cascades with energies exceeding 100 TeV, which we employ to search for correlation with radio-bright blazars. Although the currently limited neutrino sample size provides no statistically significant effects, our analysis suggests a number of possible associations with both extragalactic and Galactic sources. Specifically, we present an analysis of an observed triplet of neutrino candidate events in the Galactic plane, focusing on its potential connection with certain Galactic sources, and discuss the coincidence of cascades with several bright and flaring blazars.
Currently, the Baikal-GVD Deep Underwater Neutrino Telescope is being successfully deployed in Lake Baikal. It comprises 96 strings with 3456 optical modules. We present the status and plans for ...further deployment of the Baikal-GVD telescope and discuss the issues related to the development of the next-generation neutrino telescope in Lake Baikal.
The neutrino telescope Baikal-GVD is designed for search for high energy neutrinos whose sources are not yet reliably identified. It currently includes total of 3456 optical modules arranged on 96 ...strings, providing an effective volume of 0.6 km
for cascades with energy above 1 PeV. We discuss the first results from the partially built experiment, which is currently the largest neutrino telescope in the Northern Hemisphere and still growing up.
•TODGA – F-3 extraction system was tested with real PUREX-process raffinate.•Recovery of 99,9% of americium and curium were demonstrated.•Chromatographic separation of americium and curium was tested ...with concentrate of MA and heavy REE.•Fractions of Am a purity of more than 99.9% was obtained.
As part of PRORYV project activities dynamic tests of extraction systems (CMPO – TBP - F-3, Dyp-7 - F-3, ATP – CCD – F-3 (UNEX-T) и TODGA – F-3) were carried out. With the use of TODGA – F-3 from raffinate of PUREX-process from recycling of SNF WWER-440, the deep extraction of americium and curium was demonstrated (99,9% from the initial content). Using the concentrate of MA and heavy REE from recycling of SNF WWER-1000 experiments on chromatographic separation of americium and curium were carried out. The fractions of Am a purity of more than 99.9% was obtained. Mathematical models have been developed for all the processes studied, both for the process itself and for the operation. Verification of mathematical models on model and real products is planned.
This article discusses the influence of the cell size of the initial template, solution concentration, and number of impregnation stages on the macrostructural and strength characteristics of glassy ...carbon foams produced by template synthesis. The Novolak resin SFP-012A2 was used as a carbon precursor; its coke residue is higher than 57 wt %. Increasing the number of impregnation stages makes it possible to improve the strength characteristics while maintaining open porosity at the level of 90%. The best set of properties is demonstrated by glassy carbon foam based on polyurethane template with a porosity of 60 pores/inch and four impregnation stages using a solution with a concentration of 30 wt % due to uniform wall thickening in the material. The ultimate compression strength is 1.12 MPa, which is two times higher than that of foreign analogs; the open porosity is 91%. A decrease in the cell size of initial templates can lead to embrittlement of the material due to the formation of clusters of overlapped cells. Increasing the mechanical strength of glassy carbon foams while maintaining an open-cell structure expands the range of applications for this class of materials.
We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the ...decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q^{'2}<9 GeV^{2}, squared momentum transferred 0.1<-t<0.8 GeV^{2}, and average total center-of-mass energy squared s=14.5 GeV^{2}. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.
The development of any energy system, including nuclear, is a lengthy and multi-stage process. To evaluate the outlook, many significant factors outside the nuclear energy system and the uncertainty ...of future avenues of macroeconomic development must be taken into account. This task requires a multi-criteria approach to the analysis of the competitiveness of the technology using criteria that combine economic and safety indicators, environmental impacts, realization risks, and development outlook. This article reports the results of a multi-criteria systems analysis of alternative scenarios for the development of nuclear energy in Russia performed using international assessment tools.
The aim of this work was to design and characterize peptides based on the α-helices h1 and h2 of the ACE2 receptor, forming the interaction interface between the receptor-binding domain (RBD) of the ...SARS-CoV-2 S protein and the cellular ACE2 receptor. Monomeric and heterodimeric peptides connected by disulfide bonds at different positions were synthesized. Solubility, RBD-binding affinity, and peptide helicity were experimentally measured, and molecular dynamics simulation was performed in various solvents. It was established that the preservation of the helical conformation is a necessary condition for the binding of peptides to RBD. The peptides have a low degree of helicity and low affinity for RBD in water. Dimeric peptides have a higher degree of helicity than monomeric ones, probably due to the mutual influence of helices. The degree of helicity of the peptides in trifluoroethanol is the highest; however, for in vitro studies, the most suitable solvent is a water-ethanol mixture.
We presented basic results of the preliminary testing of acousto-optical hyperspectrometer for unmanned aerial vehicle. The image quality is rather high, so the reliable spectra for each spatial ...element can be reconstructed. The stability of sensing characteristics is studied. It is shown that warming-up of the photodetector as well as of the acousto-optic crystal results in variations of the output signal due to temperature drift. This study places additional requirements upon the system behaviour in changing environment. We discussed results of green leaves testing.
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