Result of the Neutrino-4 Experiment and the Cosmological Constraints on the Sterile Neutrino (Brief Review)

JETP Letters - We present a short discussion of the Neutrino-4 experimental results and the results of other experiments searching for the sterile neutrino. We estimated the contribution of the...     

Results of T2K and NOvA Neutrino Experiments: Neutrino Mass Ordering and CP Symmetry

Journal of Experimental and Theoretical Physics - New data concerning neutrino oscillations as obtained in the T2K and NOvA accelerator neutrino experiments are considered. Both collaborations...     

Neutrino Oscillations with Three Active and Three Sterile Neutrinos

This is an extension of estimates of the probability of μ to e neutrino oscillation with one sterile neutrino to three sterile neutrinos, using a 6x6 matrix. Since the mixing angle for only one sterile neutrino has been experimentally determined, we estimate the μ to e neutrino oscillation probability with different mixing angles for two of the sterile neutrinos.     

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...     

Search for and Study of Exotic Hadrons in the Fermilab D0 Experiment: Recent Results

Physics of Atomic Nuclei - Recent results of the studies of exotic multiquark hadrons in the Fermilab D0 experiment are reported. These refer to the search and investigation of the...     

Carpet-2 Search for PeV Gamma Rays Associated with IceCube High-Energy Neutrino Events

JETP Letters - Carpet-2 is an air-shower array at Baksan Valley, Russia, equipped with a large-area (175 m2) muon detector, which makes it possible to separate primary photons from hadrons. We...     

Consequence for Wavefunction Collapse Model of the Sudbury Neutrino Observatory Experiment

It is shown that data on the dissociation rate of deuterium obtained in an experiment at the Sudbury Neutrino Observatory provides evidence that the Continuous Spontaneous Localization wavefunction collapse model should have mass–proportional coupling to be viable.     

Search for Neutrino Bursts from Collapsing Stars by Means of the LVD and BUST Detectors

A long-term and stable operation of the LVD and BUST detectors in searches for neutrino bursts from gravitational star collapses is demonstrated, and a random origin of background pulses in the detectors is confirmed thereby. The experimental results obtained by means of the LSD and BUST detectors on February 23, 1987, are considered in detail. The probability for the possible backgroundmimicked coincidences of clusters of pulses recorded in the LSD detector at 2 : 52 UT with a group of correlations of pulses within 1 s between LSD and BUST in the interval from 1 : 45 to 3 : 45 UT is estimated. Also, coincidences of the background pulses in the LVD and BUST detectors over the period of about eight years are analyzed. The results obtained in this way give sufficient grounds to conclude that the cluster of pulses recorded by the LSD detector on February 23, 1987, at 2 : 52 UT and the coincidences of individual pulses in the LSD and BUST detectors are events associated with the gravitational collapse of SN 1987A.     

First Results of Biasing Experiments on the T-10 Tokamak

The first results of the electrode biasing experiments performed on the T-10 tokamak are presented. Positive voltage applied to an electrode inserted inside the tokamak limiter results in the H-mode transition characterised by a decrease of D emission intensity, a rise of line-average plasma density and an increase in energy lifetime. Growth of core electron and ion temperatures during the electrode biasing implies the formation of the thermal barrier in addition to the particle transport barrier.     

Present Status of the Experiment on the Search for Dark Photons by Multi-Cathode Counter

Physics of Atomic Nuclei - We describe the apparatus used in this experiment and the procedure of data treatment. We give the latest experimental results and discuss the possibility to observe...     

Search for Electroweak Production of Charginos and Neutralinos in Multileptonic Final States with the ATLAS Experiment

Physics of Atomic Nuclei - Supersymmetry, or SUSY, is one of the proposed extensions to the Standard Model, representing a solution to some of its limitations, such as the hierarchy problem. It...     

Experiments on quantum chaos using microwave cavities: Results for the pseudo-integrable L-billiard

We describe microwave experiments used to study billiard geometries as model problems of non-integrability in quantum or wave mechanics. The experiments can study arbitrary 2-D geometries, including chaotic and even disordered billiards. Detailed results on an L-shaped pseudo-integrable billiard are discussed as an example. The eigenvalue statistics are well-described by empirical formulae incorporating the fraction of phase space that is non-integrable. The eigenfunctions are directly measured, and their statistical properties are shown to be influenced by non-isolated periodic orbits, similar to that for the chaotic Sinai billiard. These periodic orbits are directly observed in the Fourier transform of the eigenvalue spectrum.     

Results and Perspectives for Short-Wavelength,Four-Wave-Mixing Experiments with Fully Coherent Free Electron Lasers

The discovery of the nonlinear optical response [1 P.A. Franken, A.E. Hill, and C.W. Peters, Physical Review Letters 7(4), 118–119 (1961).[Crossref], [Web of Science ®] , [Google Scholar]] has triggered the development of new theoretical and experimental approaches. These are based on the perspective that light-matter interactions are not necessarily cast in the picture of “one photon at a time,” typical of linear processes, but more photons can “work together” in order to coherently stimulate and probe (via nonlinear interactions) different kinds of dynamics in a sample. Nowadays, such a “multi-wave” concept is extensively used in a large array of methods, also termed wave-mixing, that have found numerous applications in almost all fields of physics, chemistry, and biology [2 N. Bloembergen, Review of Modern Physics 54(3), 685–695 (1982).[Crossref], [Web of Science ®] , [Google Scholar], 3 R.W. Boyd, Nonlinear Optics, 3^rd ed., Academic Press, New York (2008). [Google Scholar]]. Such methods are often based on third-order processes, referred to as four-wave-mixing (FWM), in which a threefold light-matter interaction results in the generation of a (fourth) signal photon, whose photon parameters (frequency, wave vector, polarization, etc.) may differ from those of the input fields. The possibility to control the latter parameters turns into the capability to selectively probe different FWM processes, which can contain distinct and complementary information. In addition to this high degree of selectivity, FWM is often featured in ultrafast time resolution and can be used to study dynamics hardly accessible by linear methods [3 R.W. Boyd, Nonlinear Optics, 3^rd ed., Academic Press, New York (2008). [Google Scholar]], such as spin waves and relaxations [4 A.R. Cameron, P. Riblet, and A. Miller, Physical Review Letters 76(25), 7493–7496 (1996).[Crossref], [Web of Science ®] , [Google Scholar], 5 C.P. Weber, Nature 437(7063), 1330–1333 (2005).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] or Raman transitions between unoccupied electronic states [6 Y. Prior, Phys. Rev. Lett. 46(2), 111–114 (1981).[Crossref], [Web of Science ®] , [Google Scholar], 7 J.R. Andrews and R.M. Hochstrasser, Chemical Physics Letters 82(3), 381–385 (1981).[Crossref], [Web of Science ®] , [Google Scholar]].     

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.     

Results of a search for 2β decay of 136Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory

A search for 2β decay of ¹³⁶Xe with two high-pressure copper proportional counters was carried out in the Baksan Neutrino Observatory. The experiment is based on comparison of spectra measured with natural and enriched xenon. No evidence was found for 2β(2ν) and 2β(0ν) decay. The decay half-life limit based on data measured for 8000 h is T _1/2 ≥ 8.5 × 10²¹ yr for 2ν mode and T _1/2 ≥ 3.1 × 10²³ yr for 0ν mode (90% C.L.). The text was submitted by the authors in English.     

Computations of Dendrites in 3-D and Comparison with Microgravity Experiments

The phase field model is used to compute numerically the temporal evolution of the interface for solidification of a single needle crystal of succinonitrile (SCN) in a three dimensional cylindrical domain with conditions satisfying microgravity experiments. The numerical results for the tip velocity are (i) consistent with the experiments, (ii) compatible with the experimental conclusion that tip velocity does not increase for larger anisotropy (e.g., for pivalic acid), (iii) different for 3D versus 2D by a factor of approximately 1.76, (iv) strongly dependent on physical value of the kinetic coefficient in the model. Also, as indicated by theory and the laboratory experiments, the results obtained for single needle crystal show that the growth velocity approaches a constant value in large time.     

Development of a Detector System for Transient Magnetic Field Experiments with Radioactive-Isotope Beams and a Test Experiment

For g-factor measurements of excited states of unstable nuclei, we have been developing a setup for the transient field experiment at RIKEN Accelerator Research Facility. For the preparation of ferromagnetic material, thick Gd foils have been annealed. In a test experiment using a ²²Ne beam, the projectile Coulomb excitation to the first excited state has been observed. This revised version was published online in September 2006 with corrections to the Cover Date.     

Search for sterile neutrinos in the neutrino-4 experiment

An experimental search for sterile neutrinos has been carried out at a neutrino facility based on the SM-3 nuclear reactor in Dimitrovgrad, Russia. The movable detector with passive shielding against the external radiation may be positioned at a distance varying between 6 and 12 m from the center of the reactor. The antineutrino flux has for the first time been measured using a movable detector placed close to the antineutrino source. The accuracy of the measurements is largely restricted by the cosmic background. The results of the measurements performed at small and large distances are analyzed in terms of the sterile-neutrino model parameters Δm ₁₄ ² and sin²2θ₁₄.