1,469 research outputs found
Can we observe the gravitational quantum states of Positronium?
In this paper we consider the feasibility of observing the gravitational
quantum states of positronium. The proposed scheme employs the flow-throw
technique used for the first observation of this effect with neutrons.
Collimation and Stark deceleration of Rydberg positronium atoms allow to select
the required velocity class. If this experiment could be realized with
positronium it would lead to a determination of g for this matter-antimatter
system at the few % level. As discussed in this contribution, most of the
required techniques are currently available but important milestones have to be
demonstrated experimentally before such an experiment could become reality.
Those are: the efficient focusing of a bunched positron beam, Stark
deceleration of Rydberg positronium and its subsequent excitation into states
with large angular momentum. We provide an estimate of the efficiencies we
expect for these steps and assuming those could be confirmed we calculate the
signal rate.Comment: 12 pages, 1 figure, contribution to the GRANIT 2014 workshop: Quantum
gravitationnal spectroscopy with ultra-cold system
Quantum ballistic experiment on antihydrogen fall
We study an interferometric approach to measure gravitational mass of
antihydrogen. The method consists of preparing a coherent superposition of
antihydrogen quantum state localized near a material surface in the
gravitational field of the Earth, and then observing the time distribution of
annihilation events followed after the free fall of an initially prepared
superposition from a given height to the detector plate. We show that a
corresponding time distribution is related to the momentum distribution in the
initial state that allows its precise measurement. This approach is combined
with a method of production of a coherent superposition of gravitational states
by inducing a resonant transition using oscillating gradient magnetic field. We
estimate an accuracy of measuring the gravitational mass of antihydrogen atom
which could be deduced from such a measurement.Comment: arXiv admin note: text overlap with arXiv:1403.478
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
Renovation's peculiarities of industrial enterprises in conditions of economic selfsufficiency
Probleme of recrienfation of building complex, to the sharp increase of share of reconstruction works, capital repair and modernisation of in-dustrial plants are concidered in this work. The conception of develop-ment and creation of unitified system of expluatation and renovation of industrial plants are worded out. This system is based on date-computer technology and taking into conciderations of real economic relations
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
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