Dependence of Coulomb capture ratio and x-ray intensities on the mesonic-particle energy spectrum

The dependence of the per-atom capture ratioA(Z₁, Z₂) and the x-ray intensity pattern on the spectral flux densityn(W) of slow mesonic particles in the target is calculated in closed form with a semiclassical theory. The intensity pattern turns out to vary only slightly withn(W) whereas the capture ratio shows a more pronounced dependence. Numerical results are presented.     

Nature of dark matter and pancake mass

If dark matter is made of collisionless particles a relation holds between the mass m of such particles, the primordial spectral index n, and the “pancake” mass. The case of dark matter of two different particles is debated here; present calculations lead to stringent limits on “supersymmetrical” particle abundance and/or to the prediction of their masses from clustering analysis.     

Chemische Zusammensetzung der kosmischen Strahlung niederenergetischer Teilchen vonZ=12 bisZ=28, gemessen in Plastikdetektoren

Results of a balloon flight experiment flown from Fort Churchill, Canada, at 1.8 g/cm² for about 10 hours in 1968 are presented. The study was made using Lexan polycarbonate plastic sheets as a particle detector. The analysis of the flux and the charge composition is based on the measurement of 313 stopping particles from Mg to Ni with energies between 150 and 400 MeV/Nucl. The identification of the tracks of the particles is achieved using the restricted energy loss criterion. The flux is corrected for scanning and detector efficiency corresponding to their charge. We are able to measure the charge of a particle with an accuracy of ±0.3 charge units in the region of the iron peak. This accuracy depends on the detailed study of the cone length versus residual range. The evenZ to oddZ ratio for chargesZ≧20 is 3. We have measured the ratios of Mn/Fe=0.34, Cr/Fe=0.42 and Ca+Sc+Ti/Fe=1.05. From these measured charge ratios a thickness of (3±1) g/cm² interstellar matter can be deduced.     

Evolution of the dark matter distribution at the galactic center

Annihilation radiation from neutralino dark matter at the Galactic center (GC) would be greatly enhanced if the dark matter were strongly clustered around the supermassive black hole (SBH). The existence of a dark matter "spike" is made plausible by the observed, steeply rising stellar density near the GC SBH. Here the time-dependent equations describing gravitational interaction of the dark matter with the stars are solved. Scattering of dark matter particles by stars would substantially lower the dark matter density near the GC SBH over 10 Gyr, due both to kinetic heating and to capture of dark matter particles by the SBH. This evolution implies a decrease by several orders of magnitude in the observable flux of annihilation products compared with models that associate a steep, dark matter spike with the SBH.     

Features of energy loss for ions with K vacancy

The change in the average charge of helium-like ions when metastable particles are present in the beam is studied. The charge fractions and average charges are calculated as functions of the target thickness for ions with Z = 3–8 at a velocity of 3.65 au. Previous data on the cross sections for electron capture and loss by metastable ions are used in the calculations. It is shown that, for all ions under consideration, the presence of metastable particles in the beam leads to an increase in the average equilibrium charge and, possibly, to a corresponding increase in energy loss and ion ranges.     

In searches for daemons

A possibility is considered of detecting Planckian particles carrying an electric charge Z≈10 and supposedly forming the dark matter of the Galactic disk, whence they are captured by combined action of the Sun and the Earth into strongly elongated Earth-crossing orbits. The flux of such dark electric matter objects, daemons, at the Earth’s orbit may reach f _⊕≈3×10⁻⁷cm⁻²s⁻¹ at a velocity about 52 km/s. Negatively charged daemons are capable of catalyzing the fusion of light (Z _n<10) nuclei. The rate of capture (and fusion) of nuclei should be particularly high in a metallic phase. A detection system is described that consists of beryllium plates 45 mm thick and 1200 cm² in area coated with a ZnS(Ag) scintillator. It is assumed that the products of the fusion reaction 2⁹Be → ¹⁸O that are ejected in amounts of up to about 10⁴ from the points of daemon entrance and exit would give rise to scintillations with a delay of about 1μs. An exposure of the system for 300 h revealed no event. The reason for the negative result can be (1) too optimistic an estimate of the flux (the inclusion of some factors could lower it by 1.5–3 orders of magnitude) and (2) the poisoning of the catalyst by capture of nuclei with Z _n≥10. The time required for the recovery of the daemon catalytic properties is estimated from the analysis of the energy release in the Sun at no less than 3×10⁻⁷ s. The analysis of the total available data suggests that the daemon flux at the Earth is about 3×10⁻⁸ cm⁻² s⁻¹. The experiments will be continued. From Yadernaya Fizika, Vol. 63, No. 6, 2000, pp. 1112–1117. Original English Text Copyright ? 2000 by Drobyshevski. This article was submitted by the author in English.     

Integrating cylinder radiometry and photometry: Application to radiant flux and irradiance measurements

In this paper, we present the detail calculations of the indirect spectral irradiance E(λ) as a function of the spectral radiant flux Φ_t(λ) of a radiating source. This relation is used to predict the integrating cylinder irradiance for a given input radiant flux as a function of the geometrical parameters and reflectivity called “multiplier constant”. The radiation transfer within a cylindrical enclosure composed of three different surfaces, the inside circular surface and the two bases in the ends, has been examined. The configuration factor is introduced. Then all the configuration factors needed for our calculation have been given in analytical form.     

Oscillations of three generations of neutrinos and the solar neutrino problem

The resonant neutrino oscillations in matter are assumed to be responsible for the observed reduction in the capture rate for the ³⁷Cl detector. The expression of the probability that a solar v_e reaches the Earth as a v_e is given in the case of three generations. In the small mixing angle approximation, we describe all the regions of neutrino parameters which give rise to a capture rate of 2.1 SNU for ³⁷Cl and we give the corresponding prediction for the ⁷¹Ga detector.     

One-electron capture in collisions of fast ions with atoms

The properties of one-electron charge transfer between ions and atomsB ^Z++A →B ^(Z?1)+ A ⁺ are studied at relative velocities of the colliding particles higher than target electron velocities. Calculations of partial and total cross sections in collisions of protons and multiply-charged ions with neutral atoms are performed and compared with experimental data. The universal curve for the capture of the targetK- andL-electrons is given. In all cases at sufficiently high collision energies the electron capture from outer shells decreases and the capture of electrons from inner shells of the target atom becomes predominant.     

Detection of Supersymmetric Dark Matter

A re-analysis of a heavy charged particle production event observed at the cloudy chamber of the Yunnan Cosmic Ray Station (YCRS) in 1972 indicates that the mysterious heavy particle may be identified as a supersymmetric (SUSY) particle produced by a bombard of a neutral SUSY cosmic ray particle on proton. Based on the assumption, following the literatures that the neutral SUSYparticle which constitutes the main fiaction of the cold dark matter is scalar neutrino (sneutrino) or neutralino (photino), we evaluate the flux of such SUSY particles which gain sufficient energies via elastic scattering with charged cosmic particles on the way to an Earth detector and the capture rates in both the sneutrino and photino cases respectively. The errors appearing in the study are briefly discussed and this work may provide a basis of designing cosmic ray detectors to search for SUSY particles from the heaven.     

Collapse of systems of relativistic particles

We prove in a very simple way that if a system of N non-relativistic particles interacting by Coulomb or gravitational forces has a (negative) binding energy increasing faster than N, the corresponding system necessarily collapses for N big enough if particles are given relativistic kinetic energy. At the same time our method allows to improve considerably a recently obtained sufficient condition on coupling constants for the collapse of ordinary matter.     

Quark-gluon state of matter and positive excess of cosmic-ray muons at high energies

The problem of the relationship between the numbers of positively and negatively charged particles in the flux of cosmic-ray muons arriving at sea level with energies in excess of 0.1 TeV (up to 100 TeV) is discussed. It is shown that the formation of quark—gluon matter as the result of high-energy nuclear interactions leads to a reduction of the positive excess in cosmic-ray muons at the above energies. At the present time, the quark-gluon state of matter is studied in accelerator experiments at colliding-particle energies of up to √s = 200 GeV per nucleon. Estimates presented in this article for the positive excess of muons having energies of up to 3 or 4 TeV are based on available data from accelerator experiments; at higher muon energies, the respective estimates are based on extrapolating these data.     

f(R,L m ) gravity

We generalize the f(R) type gravity models by assuming that the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar R and of the matter Lagrangian L _m . We obtain the gravitational field equations in the metric formalism, as well as the equations of motion for test particles, which follow from the covariant divergence of the energy-momentum tensor. The equations of motion for test particles can also be derived from a variational principle in the particular case in which the Lagrangian density of the matter is an arbitrary function of the energy density of the matter only. Generally, the motion is non-geodesic, and it takes place in the presence of an extra force orthogonal to the four-velocity. The Newtonian limit of the equation of motion is also considered, and a procedure for obtaining the energy-momentum tensor of the matter is presented. The gravitational field equations and the equations of motion for a particular model in which the action of the gravitational field has an exponential dependence on the standard general relativistic Hilbert–Einstein Lagrange density are also derived.     

Nonlinear increase in the energy input into a medium at the fusion of regularized femtosecond filaments

We consider dark matter consisting of long-living particles with masses 10⁷ GeV ? M ?10¹⁶ GeV decaying through hadronic channel as a source of high-energy neutrino. Using recent data on high-energy neutrino from IceCube and Pierre Auger experiments, we derive the upper-limits on neutrino flux from dark matter decay and constraints on dark matter parameter space. For the dark matter masses of order 10⁸ GeV the constraints derived are slightly stronger than those obtained for the same dark matter model using the highenergy gamma-ray limits.     

Effects of suprathermal particles on the dust ion-acoustic waves in a complex plasma

Dust ion-acoustic waves propagating in a complex plasma containing dusty particles and suprathermal electrons and ions are kinetically analyzed. The suprathermal particles are effectively modeled by the Lorentzian (kappa) velocity distribution function. For a collisionless and unmagnetized plasma, the full spectrum of the dispersion relation is obtained and the suprathermal particle effects on the wave frequency and the Landau damping are investigated. For a given wave number, the wave frequency decreases as the spectral index κ decreases, especially very rapidly in the low κ region. The Landau damping of the wave and its maximum are derived. They are found to be enhanced by the increase of suprathermal particles. The ion-to-electron density ratio also enhances the damping rate greatly.     

Non-thermal dark matter,high energy cosmic rays and late-decaying particles from inflationary quantum fluctuations

It has been suggested that the origin of cosmic rays above the GZK limit might be explained by the decay of particles, X, with mass of the order of 10¹² GeV. Generation of heavy particles from inflationary quantum fluctuations is a prime candidate for the origin of the decaying X particles. It has also been suggested that the problem of non-singular galactic halos might be explained if dark matter originates non-thermally from the decay of particles, Y, such that there is a free-streaming length of the order of 0.1 Mpc. Here we explore the possibility that quantum fluctuations might account for the Y particles as well as the X particles. For the case of non-thermal WIMP dark matter with unsuppressed weak interactions we find that there is a general problem with deuterium photo-dissociation, disfavouring WIMP dark matter candidates. For the case of more general dark matter particles, which may have little or no interaction with conventional matter, we discuss the conditions under which X and Y scalars or fermions can account for non-thermal dark matter and cosmic rays. For the case where X and Y scalars are simultaneously produced, we show that galactic halos are likely to have a dynamically significant component of X scalar cold dark matter in addition to the dominant non-thermal dark matter component.     

Antiproton annihilation in the galaxy as a source of diffuse γ background

A model is developed for antimatter loss by a globular cluster of antimatter stars and its annihilation with a gas of ordinary matter. The flux of photons produced in proton-antiproton annihilation is shown to reproduce the observed γ background measured by the EGRET telescope. The maximum possible number of antimatter stars presumably existing in the Milky Way Galaxy is estimated on the basis of a comparison with observational data.     

Energy loss of light ions with allowance for the presence of metastable particles in the ion beam

The change in the average ion charge due to the presence of particles in metastable states in beams of helium-like ions has been studied. The charge distributions and average charges have been calculated for ions with nuclear charges Z = 3?7 and a velocity of 3.65 au in nitrogen. The previously obtained data on the cross sections of loss and capture of electrons by metastable ions and ions in the ground state were used in the calculations. It is shown that the presence of metastable particles in ion beams leads to an increase in the average charge and energy loss for all considered ions.