Upper limit on the flux of gravitational wave bursts

Summary The data obtained with three highly sensitive gravitational wave antennas have been used to establish an improved observational upper limit on the flux of impulsive gravitational waves. Preliminary results under the assumption of a source located in the center of the Galaxy are also reported. To speed up publication, the proofs were not sent to the authors and were superised by the Scientific Committee.     

Prediction of geoeffective solar wind streams near earth according to solar observational data

A semi-empirical model for predicting solar wind (SW) streams is developed based on satellite images of the Sun and corona using a hierarchical approach. The model allows simultaneous calculation of the parameters of all three SW components, i.e., slow SW, high-speed streams from coronal holes, and interplanetary coronal mass ejections, as well as the detection of their possible interaction in the heliosphere.     

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.     

Upper limit on the photon fraction in highest-energy cosmic rays from AGASA data

A new method to derive an upper limit on photon primaries from small data sets of air showers is developed which accounts for shower properties varying with the primary energy and arrival direction. Applying this method to the highest-energy showers recorded by the AGASA experiment, an upper limit on the photon fraction of 51% (67%) at a confidence level of 90% (95%) for primary energies above 1.25 x 10(20) eV is set. This new limit on the photon fraction above the Greisen-Zatsepin-Kuzmin cutoff energy constrains the -burst model of the origin of highest-energy cosmic rays.     

Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near(560 m and 600 m flux-weighted baselines) and one far(1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay(IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020(0.992±0.021) for the Huber+Mueller(ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4–6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.     

Evaluation of the energy spectrum of solar protons according to the balloon measurement data and Monte Carlo simulation

The method for evaluating the energy spectra of solar protons at the boundary of the Earth’s atmosphere according to the data of balloon measurements carried out at the Lebedev Institute of Physics, Russian Academy of Sciences, and the results of Monte Carlo simulation of the processes of proton interaction in the Earth’s atmosphere has been developed. The balloon measurements during solar proton events make it possible to determine the absorption spectra of solar cosmic rays in the atmosphere. Comparison of the experimental data with the results of the simulation of propagation of solar protons (E _p = 10 MeV-10 GeV) in the atmosphere, based on GEANT-4, allows determination of the energy spectra of solar protons at the atmospheric boundary. The results of the determination of the energy spectra of solar protons in a number of solar proton events in the current (23th) solar activity cycle are reported.     

Upper limit to the lightest Higgs mass in supersymmetric models

Consider all models in which the effective low-energy theory has an SU(3) × SU(2) × U(1) gauge group, softly or spontaneously broken supersymmetry, and Higgs doublets. Even though, in general, mass terms in such models are arbitrary (thus “ino” masses can be pushed up to higher and higher values), one can derive mass relations between ordinary Higgs particles. The most crucial relation gives an upper bound of 93 GeV on the mass of the lightest Higgs scalar. We discuss these relations and calculate radiative corrections to them. It is shown that the upper bound can not exceed 95 GeV, and the lower limit to the mass of charged scalar is 78 GeV. Corrections to other relations are also discussed. These relations may provide the first definitive test of low-energy supersymmetry.     

Upper limit on beauty lifetime and lower limit on weak mixing angles

Muons from a multihadron sample are used to determine an upper limit τ<1.4 × 10^?12s (95% CL) on the lifetime of beauty particles. The data are obtained with the JADE detector at PETRA. The result is interpreted within the standard model.     

Upper limit on the viscosity of a nuclear liquid

Small oscillations of the atomic nucleus in the model of a viscous charged incompressible liquid drop under the action of capillary and Coulomb forces about an equilibrium spherical form are considered. As a result of investigating the frequency spectrum of intrinsic surface oscillations of the nucleus, the existence of an upper limit on the viscosity of the nuclear liquid is proven, and a precise formula for this limit is obtained.The present work is based on a paper presented at the Second All-Union Working Conference on Gravitation and the Unification of Fundamental Fields, Kiev, October 25–28, 1082.Translated from Izvestiva Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 31–35, April, 1985.It remains to thank Prof. K. P. Stanyukovich for his interest in the work and numerous useful discussions and also Prof. D. D. Ivanenko for discussions of the result obtained.     

Upper limit on additional neutrino mass eigenstate in 2 to 100 eV region from “Troitsk nu-Mass” data

We performed a search for any sign of an additional neutrino mass state in β-electron spectrum based on data reanalysis of direct electron antineutrino mass measurements in Tritium beta-decay in the Troitsk nu-mass experiment. The existing data set allows us to search for such a state in the mass range up to 100 eV. The lowest value at a 95% C.L. upper limit for the contribution of a heavy eigenstate into electron neutrino is around or less than 1% for masses above 20 eV.     

The gravity Lagrangian according to solar system experiments

In this work we show that the gravity Lagrangian at relatively low curvatures in both metric and Palatini formalisms is a bounded function that can only depart from the linearity within the limits defined by well-known functions. We obtain those functions by analyzing a set of inequalities that any theory must satisfy in order to be compatible with laboratory and solar system observational constraints. This result implies that the recently suggested f(R)gravity theories with nonlinear terms that dominate at low curvatures are incompatible with observations and, therefore, cannot represent a valid mechanism to justify the cosmic speedup.     

Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux

We report results from 120 h of live time with the Goldstone lunar ultrahigh energy neutrino experiment (GLUE). The experiment searches for < or = 10 ns microwave pulses from the lunar regolith, appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of > or = 100 EeV (1 EeV = 10(18) eV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultrahigh energy neutrino fluxes.     

Analysis of the anisotropy of the muon flux, according to data obtained by the URAGAN muon hodoscope during heliospheric disturbances

Features of studying heliospheric disturbances caused by changes in the parameters of the interplanetary magnetic field by the anisotropy of the muon flux of cosmic rays detected on the surface of the Earth by the URAGAN muon hodoscope are considered. The anisotropy of the muon flux in the period 2007–2011 is analyzed. The forecasting potential of our approaches to studying heliospheric disturbances using the penetrating component of cosmic rays is evaluated.     

Neutrino and antineutrino proton scattering data and the ratio of down to up quarks in the proton

New data on the x-dependence of the ratio of down to up quarks in the proton are presented from neutrino and antineutrino experiments using the Fermilab 15-foot bubble chamber filled with hydrogen. The new data are in good agreement with existing data from electron scattering experiments performed at SLAC but are not accurate enough at large x to discriminate between the QCD prediction and a (1 ? x) behavior as x → 1.     

Soliton junctions in the large magnetic flux limit

We study the flux tube junctions in the limit of large magnetic flux. In this limit the flux tube becomes a wall vortex which is a wall of negligible thickness (compared to the radius of the tube) compactified on a cylinder and stabilized by the flux inside. This wall surface can also assume different shapes that correspond to soliton junctions. We can have a flux tube that ends on a wall, a flux tube that ends on a monopole and more generic configurations containing all three of them. In this paper we find the differential equations that describe the shape of the wall vortex surface for these junctions. We will restrict to the cases of cylindrical symmetry. We also solve numerically these differential equations for various kinds of junctions. We finally find an interesting relation between soliton junctions and dynamical systems.