In the present work we report on the observation of an excess of gamma-ray candidate events in temporal and spatial coincidence with the IceCube high-energy neutrino alert consistent with the origin ...in the Cygnus Cocoon region. The observations have been performed with Carpet-2, a surface air-shower detector equipped with a large-area muon detector at the Baksan Neutrino Observatory in the Northern Caucasus. As well as we report about the current state of the Carpet-3 facility, which includes a muon detector with an increased area and an expanded surface array. The main aim of the Carpet-3 facility is the registration of cosmic gamma-rays with energy larger than 100 TeV. Moreover, it gives a possibility to carry out research on the composition of primary cosmic rays around the knee. It is planned that the Carpet-3 EAS array will be operation by the end of 2021.
A model is proposed in which the electrical voltage measured between the electrodes in Lake Baikal is a consequence of two effects: electrochemical processes near the electrodes and a positive charge ...current flowing through the lake. The electrochemical component of the voltage in the case of lead electrodes arises due to the difference in concentrations of carbonate anion—
at different depths. In the case of the use of chlorine-silver electrodes, only the effect of the positive charge current flowing through the lake is measured. We proposed an interpretation of an increase of electrical voltage registered in Lake Baikal during an earthquake in August 2008. The reason for the increase in voltage is the release of positively charged hydrogen-containing gases from the Earth’s interior.
The Carpet-3 array at the Baksan Neutrino Observatory is designed to detect extensive air showers generated by primary cosmic rays of more than 100 TeV in energy. The main aim is to search for cosmic ...extrahigh-energy gamma rays. In this work, we describe the current state of the facility and the results from searching for extrahigh-energy photons from regions of the localization of candidates for gravitational-wave events detected by LIGO/Virgo during the third observational period.
We provide the indication of high flux of \(^{40}\)K geo-antineutrino and geo-neutrino (\(^{40}\)K-geo-(\(\bar{\nu} + \nu\))) with Borexino Phase III data. This result was obtained by introducing a ...new source of single events, namely \(^{40}\)K-geo-(\(\bar{\nu} + \nu\)) scattering on electrons, in multivariate fit analysis of Borexino Phase III data. Simultaneously we obtained the count rates of events from \(^7\)Be, \(pep\) and CNO solar neutrinos. These count rates are consistent with the prediction of the Low metallicity Sun model SSM B16-AGSS09. MC pseudo-experiments showed that the case of High metallicity Sun and absence of \(^{40}\)K-geo-(\(\bar{\nu} + \nu\)) can not imitate the result of multivariate fit analysis of Borexino Phase III data with introducing \(^{40}\)K-geo-(\(\bar{\nu} + \nu\)) events. We also provide arguments for the high abundance of potassium in the Earth.
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino ...events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3) eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.
Some discrepancies have been reported between observed and simulated muon content of extensive air showers: the number of observed muons exceeded the expectations in HiRes-MIA, Yakutsk and Pierre ...Auger Observatory data. Here, we analyze the data of the Moscow State University Extensive Air Shower (EAS–MSU) array on Eμ ≳ 10 GeV muons in showers caused by ∼(1017−1018) eV primary particles and demonstrate that they agree with simulations (QGSJET-II-04 hadronic interaction model) once the primary composition inferred from the surface-detector data is assumed.
New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a ...data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3) eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3) eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.
Abstract
Borexino collaboration announced the observation of CNO neutrinos flux. Its value appeared larger than expected in case of the Sun high metallicity model. This could be regarded as evidence ...of large potassium content inside the Earth. The potassium abundance can reach (1.5 ± 1.0)% in the whole Earth and the Earth heat flux can be at the level of 200-300 TW. To resolve the problem a new experiment is demanded with a detector similar to Borexino one but better in backgrounds or a detector with another techniques of neutrino measurement, for example on base of
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In.
Borexino collaboration announced the observation of CNO neutrinos flux. Its value appeared larger than expected in case of the Sun high metallicity model. This could be regarded as evidence of large ...potassium content inside the Earth. The potassium abundance can reach (1.5 ± 1.0)% in the whole Earth and the Earth heat flux can be at the level of 200-300 TW. To resolve the problem a new experiment is demanded with a detector similar to Borexino one but better in backgrounds or a detector with another techniques of neutrino measurement, for example on base of 115In.
New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter theta_{23}. Using an off-axis neutrino beam with a peak energy of 0.6 GeV ...and a data set corresponding to 6.57 x 10^{20} protons on target, T2K has fit the energy-dependent nu_mu oscillation probability to determine oscillation parameters. Marginalizing over the values of other oscillation parameters yields sin^2 (theta_{23}) = 0.514 +0.055/-0.056 (0.511 +- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m^2_{32} = 2.51 +- 0.10 x 10^{-3} eV^2/c^4 (inverted hierarchy: Delta m^2_{13} = 2.48 +- 0.10 x 10^{-3} eV^2/c^4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.
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