The search for neutrino bursts from core collapse Supernovae at the Baksan Underground Scintillation Telescope

The current status of the experiment on recording neutrino bursts from core collapse stars is presented. The actual observational time T (from June 30, 1980 until December 31, 2009) is 25.58 years. An upper bound of the mean frequency of gravitational collapse in our Galaxy f _col < 0.090 year^?1 at a 90% confidence level. The results of studying single events at the facility in the case of muon inelastic interaction of cosmic rays with the matter of the detector are presented.     

Search for High-Energy Neutrinos from GW170817 with the Baikal-GVD Neutrino Telescope

JETP Letters - The Advanced Laser Interferometer Gravitational-Wave Observatory and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short...     

Upper limit on the cross section for elastic neutralino-nucleon scattering in a neutrino experiment at the Baksan Underground Scintillator Telescope

The results of a neutrino experiment that involved 24.12 yr of live time of observation of muons from the lower Earth’s hemisphere with the aid of the Baksan Underground Scintillator Telescope are presented. In the problem of searches for a signal from the annihilation of dark matter in the Sun, an upper limit on the cross section for the elastic scattering of a weakly interacting massive particle (WIMP) on a nucleon was obtained at a 90% confidence level from an analysis of data accumulated within 21.15 yr of live time of observation. A neutralino in a nonminimal supersymmetric theory was considered for a WIMP. The best limit at the Baksan Underground Scintillator Telescope on the cross section for spin-dependent neutralino interactionwith a proton corresponds to 3×10^?4 pb for the neutralino mass of 210 GeV/c ². This limit is three orders of magnitude more stringent than similar limits obtained in experiments that detected directly WIMP scattering on target nuclei.     

Forty Years to the Artemovsk Scintillation Detector for Neutrinos

The current status of the ASD (Artemovsk scintillation detector) experiment aimed at search for a neutrino flux from gravitational collapses of stellar cores is presented. Experimental data obtained for 40 years of operation of the detector situated in a salt mine at a depth of 570 mwe are processed. The results obtained by calculating the expected signal in the detector on the basis of two models of supernova explosion are described. No candidates for neutrino bursts from gravitational star collapses have been revealed: the limit on the frequency of gravitational collapses was found to be less than one event per 17.15 yr at a 90% confidence level (f_col < 0.058 yr^?1).     

On the Efficiency of the Coincidence Search in Gravitational Wave Experiments

We discuss the problem of the detection of gravitational waves (GW) signals with small energy signal to noise ratio (SNR). We consider coincidence experiments between data processed by optimum filters matched to delta-like bursts. It is shown, by calculation and by simulation, that, because of the noise, the event lists produced by the same signals on different detectors, using the same filters, overlap only partially—about 30 percent for SNR close to the threshold used for defining the events. Furthermore, because of the noise, the correlation of the event energy between identical detectors is weak and cannot be used as a strong discriminator against noise in coincidence search, even for SNR = 10 or more.     

Search for low-energy neutrino radiation accompanying gamma-ray bursts on the Baksan subterranean scintillation telescope

An analysis aimed at finding possible neutrino radiation accompanying gamma-ray bursts in a 24-h period about them is performed on the basis of the data in the 4B BATSE Gamma-Ray Burst Catalog and data from the Baksan scintillation telescope according to a program for finding neutrinos from collapsing stars. Values significantly exceeding the background are not discovered. A lower bound for the distance to the source is established under the assumption that the anticipated radiation has characteristics similar to the characteristics of collapse neutrinos. It attests to the cosmological origin of gamma-ray bursts with a high degree of probability. Zh. éksp. Teor. Fiz. 114, 1921–1929 (December 1998)     

Possible Resonator Configurations for the Spherical Gravitational Wave Antenna

We solve algebraically the equations of motion for a spherical antenna coupled to an arbitrary number of small resonators, free to move radially, and investigate the conditions under which damping forces can be neglected in the system. We show that in order that the antenna's modes be decoupled a preferred distribution of the resonators on its surface should be used. We find that either 5, 6, 10 or 16 resonators can be used as long as they are conveniently positioned on the antenna's surface. We calculate and analyse the frequency shift and the signal-to-noise ratio of the coupled system for the various distributions studied.     

Parametric Transducers for the Advanced Cryogenic Resonant-Mass Gravitational Wave Detectors

It is shown that a large improvement in liquid helium and ultra-cryogenically cooled resonant-mass gravitational wave detectors can be achieved through improved parametric transducers using either low loss sapphire dielectric resonators or niobium re-entrant cavities. Performance is analysed in relation to the existing resonant bar antenna Niobe and to massive spherical detectors. Applied to Niobe, a millisecond burst sensitivity of order 10^–20 can be achieved, corresponding to a spectral strain sensitivity of 2 × 10^-22 Hz with a 50 Hz bandwidth. Applied to an ultra-cryogenic 117 tonne spherical detector made from CuAl, a spectral strain sensitivity of better than 2 ×10^-23/ Hz with a bandwidth of order 100 Hz can be achieved, which is close to the quantum limit. This sensitivity is comparable to that of advanced interferometer detectors at this frequency.     

Search for the Galactic Disk and Halo Components in the Arrival Directions of High-Energy Astrophysical Neutrinos

The arrival directions of 40 neutrino events with energies ?100 TeV, observed by the IceCube experiment, are studied. Their distribution in the Galactic latitude and in the angular distance to the Galactic Center allow searching for the Milky-Way disk and halo-related components, respectively. No statistically significant evidence for the disk component is found, though even 100% disk origin of the flux is allowed at the 90% confidence level. Contrary, the Galactic Center–Anticenter dipole anisotropy, specific for dark-matter decays (annihilation) or for interactions of cosmic rays with the extended halo of the circumgalactic gas, is clearly favored over the isotropic distribution (the probability of fluctuation of the isotropic signal is ~2%).     

Neutrinos from CNO cycle at the present epoch of the solar neutrino research

The CNO cycle contributes only a small fraction to the energy generated in the Sun but there’s still no experimental data on exactly how small this contribution is. After the results of Borexino experiment the CNO neutrinos it is the last missing chain to compose the total picture of the energy generation of the Sun. To get precision in the evaluation of the flux of pp-neutrinos one needs to measure the flux of CNO neutrinos. Then it will be possible to address the question on the presence of still unknown (hidden) sources of solar energy and/or on the presence of sterile neutrinos. The future experimental program to measure the effect from CNO neutrinos is discussed.     

High-Order Harmonics from Laser Irradiated Electron Density Singularity Formed at the Bow Wave in the Laser Plasma

Physics of Wave Phenomena - The electron density singularity formed at the joining area of relativistic wake wave and bow waves has been proposed as a novel relativistic electron mirror regime to...     

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.     

Study on the Scintillation for Optical Wave Propagation in the Slant Path Through the Atmospheric Turbulence

Based on the theory of optical wave propagation in the slant path and the ITU-R turbulence structure constant model which is altitude dependent, the modified Rytov method, which is applicable to the optical wave propagation in the horizontal path, is extended to the propagation in the slant path. According to the spectrum model with non-zero inner scale, the scintillation index as a function of the Rytov variance is obtained from weak to strong fluctuation regions with plane wave and sphere wave incidence, respectively. Finally, the scintillation index with different zenith angles is analyzed, and comparison between the results of the modified method and experimental measurements is given and discussed in detail.     

Search for nu(e) from the sun at Super-Kamiokande-I

We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.     

HERMES五夸克强子态Θ+实验探索

一个新的强子态的实验证据在2?7.6GeV正电子轰击氘靶产生的虚光子产物中被发现.HERMES通过分析衰变道K0sp→π+π–p,在K0sp不变质量谱上质量1528±2.6(stat.)±2.1(sys.)MeV处观察到共振峰.该共振峰可以被解释为理论预言的五夸克强子态Θ+(uudds).而K+p不变质量谱上未能观察到共振预示Θ+很可能是同位旋单态.     

Prospects of the search for neutrino bursts from supernovae with Baksan large volume scintillation detector

Observing a high-statistics neutrino signal from the supernova explosions in the Galaxy is a major goal of low-energy neutrino astronomy. The prospects for detecting all flavors of neutrinos and antineutrinos from the core-collapse supernova (ccSN) in operating and forthcoming large liquid scintillation detectors (LLSD) are widely discussed now. One of proposed LLSD is Baksan Large Volume Scintillation Detector (BLVSD). This detector will be installed at the Baksan Neutrino Observatory (BNO) of the Institute for Nuclear Research, Russian Academy of Sciences, at a depth of 4800 m.w.e. Low-energy neutrino astronomy is one of the main lines of research of the BLVSD.     

Gravitational radiation from inspiralling compact binaries completed at the third post-Newtonian order

The gravitational radiation from point particle binaries is computed at the third post-Newtonian (3PN) approximation of general relativity. Three previously introduced ambiguity parameters, coming from the Hadamard self-field regularization of the 3PN source-type mass quadrupole moment, are consistently determined by means of dimensional regularization, and proved to have the values xi=-9871/9240, kappa=0, and zeta=-7/33. These results complete the derivation of the general relativistic prediction for compact binary inspiral up to 3.5PN order, and should be of use for searching and deciphering the signals in the current network of gravitational wave detectors.     

Search for Majoron at the COMET experiment

A new Goldstone particle named Majoron is introduced in order to explain the origin of neutrino mass via some new physics models assuming that neutrinos are Majorana particles. By expanding the signal region and using likelihood analysis, it becomes possible to search for Majoron using experiments originally designed to search for begin{document}$ mu-e $end{document} conversion. For the COMET experiment, the sensitivity of process begin{document}$ mu rightarrow eJ $end{document} is able to reach begin{document}$ {cal{B}}(mu rightarrow eJ)=2.3times 10^{-5} $end{document} in Phase-I and begin{document}$ O(10^{-8}) $end{document} in Phase-II. Meanwhile, the sensitivities to search for Majoron in future experiments are also discussed in this article.