270 research outputs found
The comb-like representations of cellular ordinal balleans
Given two ordinal and , let be a function such that, for each , We define a mapping by the rule: if then , . The pair is called a comb defined by . We show that each cellular
ordinal ballean can be represented as a comb. In {\it General
Asymptology}, cellular ordinal balleans play a part of ultrametric spaces.Comment: 5 pages, preprin
Experimental constraints for additional short-range forces from neutron experiments
We present preliminary results on sensitivity of experiments with slow
neutrons to constrain additional forces in a wide distance range: from
picometers to micrometers. In the sub-nanometer range, available data on
lengths of neutron scattering at nuclei provide the most competitive
constraint. We show that it can be improved significantly in a dedicated
measurement of asymmetry of neutron scattering at noble gases. In the
micrometer range, we present sensitivity of the future GRANIT experiment.
Further analysis will be presented in following publications.Comment: presented in "les rencontres de Moriond" 2007 conferenc
Antideuteron production in proton-proton and proton-nucleus collisions
The experimental data of the antideuteron production in proton-proton and
proton-nucleus collisions are analyzed within a simple model based on the
diagrammatic approach to the coalescence model. This model is shown to be able
to reproduce most of existing data without any additional parameter.Comment: To appear in Eur. Phys. J A (2002
Spontaneous emission of graviton by a quantum bouncer
Spontaneous emission of graviton rates for the quantum bouncer states are
evaluated
Antiproton annihilation on light nuclei at very low energies
The recent experimental data obtained by the OBELIX group on D and
He total annihilation cross sections are analyzed. The combined
analysis of these data with existing antiprotonic atom data allows, for the
first time, the imaginary parts of the S-wave scattering lengths for the two
nuclei to be extracted. The obtained values are: for D and for He. This
analysis indicates an unexpected behaviour of the imaginary part of the
-nucleus S-wave scattering length as a function of the atomic weight
A: (p) > (D) > (He).Comment: 13 pages, 5 figure
Parameterization of the antiproton inclusive production cross section on nuclei
A new parameterization of the antiproton inclusive production cross section
in proton-proton and proton-nucleus collisions is proposed. A sample of
consistent pA->pbar X$ experimental data sets measured on 1<A<208 nuclei, from
12 GeV up to 400 GeV incident energy, have been used to constrain the
parameters. A broader energy domain is covered for the pp->pbar X reaction with
a simplified functional form used in the fits. The agreement obtained with the
data is good. The results are discussed.Comment: 10 pages, 11 figures, 7 tables, submitted to Phys. Rev.
Gravitational resonance spectroscopy with an oscillating magnetic field gradient in the GRANIT flow through arrangement
Gravitational resonance spectroscopy consists in measuring the energy
spectrum of bouncing ultracold neutrons above a mirror by inducing resonant
transitions between different discrete quantum levels. We discuss how to induce
the resonances with a flow through arrangement in the GRANIT spectrometer,
excited by an oscillating magnetic field gradient. The spectroscopy could be
realized in two distinct modes (so called DC and AC) using the same device to
produce the magnetic excitation. We present calculations demonstrating the
feasibility of the newly proposed AC mode
A New Constraint for the Coupling of Axion-like particles to Matter via Ultra-Cold Neutron Gravitational Experiments
We present a new constraint for the axion monopole-dipole coupling in the
range of 1 micrometer to a few millimeters, previously unavailable for
experimental study. The constraint was obtained using our recent results on the
observation of neutron quantum states in the Earth's gravitational field. We
exploit the ultimate sensitivity of ultra-cold neutrons (UCN) in the lowest
gravitational states above a material surface to any additional interaction
between the UCN and the matter, if the characteristic interaction range is
within the mentioned domain. In particular, we find that the upper limit for
the axion monopole-dipole coupling constant is (g_p g_s)/(\hbar c)<2 x 10^{-15}
for the axion mass in the ``promising'' axion mass region of ~1 meV.Comment: 5 pages 3 figure
Frequency shifts in gravitational resonance spectroscopy
Quantum states of ultracold neutrons in the gravitational field are to be
characterized through gravitational resonance spectroscopy. This paper
discusses systematic effects that appear in the spectroscopic measurements. The
discussed frequency shifts, which we call Stern-Gerlach shift, interference
shift, and spectator state shift, appear in conceivable measurement schemes and
have general importance. These shifts have to be taken into account in
precision experiments
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