Neutrino-induced and atmospheric single-muon fluxes measured over five decades of intensity by LVD at Gran Sasso Laboratory

We report data taken by the LVD Experiment during a live-time period of 11 556 h. We have measured the muon intensity at slant depths of standard rock from about 3000 hg/cm² to about 20 000 hg/cm². This is an exclusive study, namely our data include only events containing single muons. This interval of slant depth extends into the region where the dominant source of underground muons seen by LVD is the interaction of atmospheric neutrinos with the rock surrounding LVD. The interesting result is that this flux is independent of slant depth beyond a slant depth of about 14 000 hg/cm² of standard rock. Due to the unique topology of the Gran Sasso Laboratory the muons beyond about 14 000 hg/cm² of standard rock are at a zenithal angle near 90°. Hence we have, for this fixed angle, a muon flux which is independent of slant depth. This is direct evidence that this flux is due to atmospheric neutrinos interacting in the rock surrounding LVD. The value of this flux near 90° is (8.3 ± 2.6) × 10⁻¹³ cm⁻² s⁻¹ sr⁻¹, which is the first reported measurement at a zenithal angle near 90° and for slant depths between 14 000 and 20 000 hg/cm². Our data cover over five decades of vertical intensity, and can be fit with just three parameters over the full range of our experiment. This is the first time a single experiment reports the parameters of a fit made to the vertical intensity over such a large range of standard rock slant depth. The results are compared with a Monte Carlo simulation which has as one of the two free parameters γ_πκ, the power index of the differential energy spectrum of the pions and kaons in the atmosphere. This comparison yields a value of 2.75 ± 0.03 for γ_πκ, where the error includes the systematic uncertainties. Our data are compared to other measurements made in our slant depth interval. We also report the value of the muon flux in Gran Sasso at θ = 90° as a function of the azimuthal angle.     

Maximum likelihood estimation of the mean parallax and kinematic parameters of the Pleiades

A simultaneous, maximum-likelihood determination of the distance and kinematic parameters of the Pleiades is made. The results are: distance of the cluster d = 135.56 ± 0.72 pc, dispersion σ_d = 7.66 ± 0.80 pc; space velocity V = 25.94 ± 0.13 km/s, dispersion σ_v = 0.58 ± 0.09 km/s coordinates of the convergent point A = 101.95° ± 0.47°, D = −41.36° ± 0.29°.     

Determination of rotational parameters of asteroid (360) Carlova

Information on the rotational parameters of asteroids may provide data for research on the collision and evolution of asteroids, or even the evolution of the solar system. We carried out new CCD photometric observation of the main belt carbon-type asteroid (360) Carlova with the 1-m telescope of Yunnan Observatory, and obtained the following results:. rotational sidereal period, 0.25780417 ± 0.00000003d, ecliptic coordinates of the rotating axis, (95°±3°, 40°±1°). These are found by using the epoch-method of retrieval with our and previously published photometric data. Our results are consistent with those of our predecessors, while being slightly more accurate.     

A kinematic study of the Galaxy

Using the proper motion and parallax data for 1011 O-B stars in the Hipparcos Catalogue we have derived the Oort constants, A = 17.60 ± 0.21 (km/s)/kpc, B = −14.62 ± 0.20 (km/s)/kpc, and a solar velocity V = 16.7 ± 0.10 km/s in the direction l = 45.3° ± 2.8°, b = 21.0° ± 2.3°. For a galactocentric distance of the sun of R₀ = 8.5 kpc, we then get a galactic rotational velocity of the solar neighbourhood of V_lsr = 273.9 km/s, obviously much higher than the IAU published value of 220 km/s. We have investigated the cause for this difference.     

Galactic cosmic-ray anisotropy and its heliospheric modulation, inferred from the sidereal semidiurnal variations observed in the rigidity range 300–600 GV with multidirectional muon telescope at Sakashita underground station

The existence of sidereal semidiurnal variation of cosmic-ray intensity in a rigidity region 10²-10³ GV has been reported by many researchers, but there is no consensus of opinion on its origin. In this paper, using the observed semidiurnal variations in a rigidity range (300–600 GV) with 10 directional muon telescopes at Sakashita underground station (geog. lat. = 36°, long. = 138°E, DEPTH = 80 m.w.e.), the authors determine the magnitudes (η₁, η₂) and directions (a₁, a₂) of the first- and second-order anisotropies in the following galactic cosmic-ray intensity distribution (j)

jdp = j₀{1 + η₁P₁(cos χ₁) + η₂P₂(cos χ₂)}dp

, where P_nis the nth order spherical function and χ_n is the pitch angle of cosmic rays with respect to a_n. For the determination, the influence of cosmic-ray's heliomagnetospheric modulation, geomagnetic deflection and nuclear interaction with the terrestrial material and also of the geometric configuration of the telescopes are taken into account. Usually, the semidiurnal variation is produced by the second-order anisotropy. The present observation, however, requires also the first-order anisotropy which usually produces only the diurnal variation, but can produce also the semidiurnal variation as a result of the heliospheric modulation. The first- and second-order anisotropies are characterized with η₁) > 0 and η₂ < 0 have almost the same direction (a₁ a₂) specified by the right ascension ( 0.75 h) and declination (δ 50°S) and, therefore, they can be expressed, as a whole, by an axis-symmetric anisotropy of loss-cone type (i.e. deficit intensities in a cone). It is noteworthy that this anisotropy approximately coincides with that inferred from the air shower observation at Mt Norikura in the rigidity region 10⁴ GV.     

Cataclysmic variables III. AC Cancri

AC Cnc is a nova-like, eclipsing binary of period 7^h13^m. I chose it for observation because its eclipses are rather symmetrical. A photometric solution gives inclination i = 74.5° ± 0.8°, mass of white dwarf M₁ = 0.74 ± 0.07 M, mass of the late-type companion, M₂ = 0.97 ± 0.8 M. Temperature of the accretion disk varies approximately as inverse half-power of the radial distance, the temperature at the edge of the disk is 7600 K. Rate of mass transfer from the late-type star to the white dwarf is 7(−9) M/yr. The distance of AC Cnc is 500 ± 100 pc.     

A theoretical study of the direction and polarization of solar radio millisecond spike radiation

We investigated the angular direction and polarization of the solar radio millisecond spike emission in the model in which the spike emission is due to the second harmonic instability modes driven by electron cyclotron maser of loss cone distributed electrons during the propagation of a nonlinear plasma density wave near the magnetic mirror. We found that, when the angle θ between the wave vector and the magnetic field is > 60 °, the emission is in 100% X-mode polarization; when 40 ° < θ<60 °, the emission is in 100% O-mode polarization provided the amplitude of the density wave is below a certain limit; above that limit, the polarization will fall from 100% O-mode to even the X-mode. We also found that only 0.1% of the free energy of energy carrying electrons in the source region is converted into radiation wave energy.     

3-D period doubling and magnetic moments of particles

Several invariant properties of matter seem to fit remarkably well to quantized values obtained from Planck domain units by period doubling in three dimensions. The units are defined using natural constants only. Such properties include the elementary electric charge, electron and proton rest energies and others. It has been shown by W. G. Tifft that the quantized redshifts of galaxies fit the pattern, too. Magnetic moments of the electron, proton, neutron, muon and lambda particles also seem to obey the doubling rule. The same number of doublings seems to yield the electron and proton rest masses and magnetic moments correspondingly. The proton rest mass is E₀×2^–64 and the magnetic moment µ _o × 2⁶⁴, where E₀ and µ _o are the Planck domain units. The corresponding exponent of 2 for the electron is 75.66. The units for the proton and the electron differ by a factor of . The magnetic moment of the muon suggests a close relationship between the magnetic structures of the muon and the proton, whereas the lambda particle seems to be related to the neutron. Reasons for the supposed existence of quantized 3-d time are represented.     

Video observation of meteors at Yunnan Observatory

In the last 20 years, with the development of the CCD and image intensifiers, the use of small flexible video meteor observation systems has gradually increased, with the prospect that one day video observation will replace the visual observation and ordinary photographic observations. In this paper we report on the research and development of the No.1 meteor-comet video camera system of Yunnan Observatory and some preliminary observed results. The system consists of 5 changeable modules; it has a 36° large-field camera dedicated to the observation of meteors, with which a magnitude 6 star can be recorded on a single frame with an accuracy of about 0.2 mag. We also present a comparison of the video camera system with the traditional photographic system, and outline the merits, possible improvements and future development of the video system.     

The troposphere-stratosphere radiation field at twilight: A spherical model

Time-dependent calculations of trace constituent distributions require as input the dissociating radiation field as a function of altitude and solar zenith angle. An isotropic, spherical, multiple scattering model of the radiation field has been developed to determine the radiation field at twilight. Comparison of the spherical model with a plane parallel model at twilight shows that: (1) for solar zenith angles less than 92°, plane parallel solutions for the source function are suitable if the initial deposition of solar energy is calculated for a spherical atmosphere; (2) for solar zenith angles greater than 92°, the plane parallel radiation field can be several orders of magnitude smaller than that calculated with the spherical model; (3) at altitudes above 40 km and at all solar zenith angles, the spherical model predicts 10–20% less radiation than the radiation field calculated with the plane parallel model. Calculations of the rate of photodissociation of NO₂ in the troposphere and stratosphere show that the spherical model yields significantly higher values at solar zenith angles greater than 92°.     

The cosmic ray primary composition in the “knee” region through the EAS electromagnetic and muon measurements at EAS-TOP

The evolution of the cosmic ray primary composition in the energy range 10⁶–10⁷ GeV (i.e. the “knee” region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array (Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number (N_μ) and shower size (N_e) spectra, and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee, and therefore the possibility that the knee itself is due to a break in their energy spectrum (at E_k^He=(3.5±0.3)×10⁶ GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO), and heavy (Fe). At primary energies E₀≈10⁶ GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group (γ_p,He>3.1), (ii) a spectrum of the intermediate mass group harder than the one of the light component (γ_CNO2.75, possibly bending at E_k^CNO≈(6–7)×10⁶ GeV), (iii) a constant slope for the spectrum of the heavy primaries (γ_Fe2.3–2.7) consistent with the direct measurements. In the investigated energy range, the average primary mass increases from lnA=1.6–1.9 at E₀1.5×10⁶ GeV to lnA=2.8–3.1 at E₀1.5×10⁷ GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model (QGSJET in CORSIKA) used for the interpretation are discussed.     

Galactic kinematics derived from classical cepheids

On the basis of radial velocity and Hipparcos proper motion data, we have analyzed the galactic kinematics of classical Cepheids. Using the 3-D Ogorodnikov-Milne model we have determined the rotational velocity of the Galaxy to be V₀ = 240.5 ± 10.2 km/s, on assuming a glactocentric distance of the Sun of R₀ = 8.5 kpc. The results clearly indicate a contracting motion in the solar neighbourhood of (∂V_θ∂θ)/R = −2.60 ± 1.07 km s⁻¹ kpc⁻¹, along the direction of galactic rotation. Possible reason for this motion is discussed. The solar motion found here is S = 18.78 ± 0.86 km/s in the direction l = 54.4° ± 2.9° and b = +26.6° ± 2.6°.     

Measurements of radio noise at 0.700 mc and 2.200 mc from a high-altitude rocket probe

Radio noise observations at frequencies of 0·700 Mc and 2·200 Mc were made at altitudes between 3000 and 11,000 km from a Blue Scout Jr. high-altitude rocket probe on 30 July 1963. A steady background flux of (7·5₋₃⁺⁶) × 10⁻¹⁹ W m⁻²)(c/s)⁻¹ at 0·700 Mc and (1·8^+1.0_−0.5 × 10⁻¹⁹ W m⁻² (c/s)⁻¹ at 2·200 Mc was observed. Assuming a galactic origin of the observed fluxes at both frequencies, the averaged sky brightnesses are b(0·700 Mc) = (6₋₃⁺⁵) × 10⁻²⁰ W m⁻² (c/s)⁻¹ sr⁻¹b(2·200 Mc) = (1.4^+1.0_−0.5 × 10⁻²⁰ W m⁻² (c/s)⁻¹ sr⁻¹ The observed brightness at 2·200 Mc is in reasonable agreement with the results of other observers. The apparent brightness at 0·700 Mc is, however, greater than was expected from previous observations. An alternative source of the 0·700 Mc flux in the terrestrial exosphere, as well as characteristics of several noise bursts observed during the flight, is briefly discussed.     

Derivation ofv μ/v μ and the spectra of neutrinos from pions and kaons produced by primary cosmic rays throughp-nucleus collisions

The muon neutrino-antineutrino flux ratios, viz.,v /v generated from the decays of charged pions and kaons in atmosphere have been derived from the latest primary spectrum and the CERN ISRpp-collision data modified forp-nucleus interactions. The dynamical method of Allkoferet al. (1978) has been used in the present investigation. The estimated result forv /v yields 1.39 and 1.70 asE0 and , respectively. The neutrino fluxes from pion- and kaon-decay spectra have been calculated. Attention has been paid on prompt neutrino spectrum calculation from the decays ofD mesons. A rough estimate on the prompt muon spectrum has been given. The calculated results have been compared with the previous available results.     

Optical identification and observational study of unidentified IRAS LRS sources. 2. Observations of sources with the silicate feature in the 13–24northern sky region

JHK photometry was carried out for some of the sources with the silicate feature in the sky region 13^h < < 24^h, 0° < δ < 66° and a discussion on several peculiar objects was made.     

A study of “chorus” observed at Australian stations

The very-low-frequency emission known as “chorus” has been studied for four Australian recording stations. The phenomenon exhibits a maximum of occurrence at about geomagnetic latitude 60° and occurs only about one-tenth as frequently at geomagnetic latitude 45°. It was never definitely observed at geomagnetic latitude 35°. Marked diurnal variations are present with morning peaks for all stations and also an evening peak at Adelaide and Hobart. Analysis of the diurnal variations suggests that two different mechanisms are involved. The average strength of chorus increases with increasing value of K-index at lower latitude stations and shows a maximum at moderate values of the index for geomagnetic latitude 61°. This is interpreted as meaning that the region of maximum average-chorus-strength moves towards lower latitudes at times of magnetic disturbance.     

Measurement of the absolute proper motion of M3 and its space motion

We have measured the absolute proper motions of 534 stars in a 1.5° × 1.5° region around the cluster M3, using 14 plates taken with a 40-cm refractor spanning 80 years. 24 stars in the ACT catalogue were used to define the reference frame and the reduction was made using the central overlapping technique. Using the new data, the membership probabilities were redetermined. The mean absolute motion of the cluster was found to be −0.3 ± 0.3 mas/yr in R.A., and −3.1 ± 0.3 mas/yr in declination. Combining the present data with the known distance and radial velocity, the three-dimensional galactic orbit of M3 was calculated for Allen's galactic potential.     

J 2000.0 positions and proper motions of 257 stars in the central part of the Praesepe astrometric standard region

We given the J2000.0 position and proper motions of 257 stars in the central 1.5° × 1.5° area of the Praesepe astrometric standard region with accuracies of 0.005˜0.10 arcsec for the position in each direction and 0.0002˜0.006 arcsec/yr for the proper motions in each direction.