648 research outputs found
Optical trapping of anti-hydrogen towards an atomic anti-clock
The Anti-Matter Factory at CERN is gearing up, commissioning of the Extra Low
ENergy Antiprotons (ELENA) ring is ongoing and the first anti-protons are
foreseen to circulate in the decelerator very soon. The unprecedented flux of
low energy antiprotons delivered by ELENA will open a new era for precision
tests with antimatter including laser and microwave spectroscopy and tests of
its gravitational behaviour. Here we propose a scheme to load the ultra cold
anti-hydrogen atoms that will be produced by the GBAR experiment in an optical
lattice tuned at the magic wavelength of the 1S-2S transition in order to
measure this interval at a level comparable or even better than its matter
counter part. This will provide the most sensitive test of CPT symmetry
parametrised in the framework of the Standard Model Extension.Comment: 7 pages, 2 Figure
Testing conformal mapping with kitchen aluminum foil
We report an experimental verification of conformal mapping with kitchen
aluminum foil. This experiment can be reproduced in any laboratory by
undergraduate students and it is therefore an ideal experiment to introduce the
concept of conformal mapping. The original problem was the distribution of the
electric potential in a very long plate. The correct theoretical prediction was
recently derived by A. Czarnecki (Can. J. Phys. 92, 1297 (2014))
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
Status and prospects of the NA64 experiment at the CERN SPS
NA64 is a fixed target experiment at the CERN SPS designed as a hermetic
general purpose detector to search for Dark Sector physics in missing energy
events from electron/positron, hadrons, and muon scattering off nuclei. In this
contribution to the FIPs 2022 workshop, we review the current status and
prospects of NA64.Comment: 5 pages, 4 figures, prepared for the proceedings of the FIPs 2022
workshop, v2 some typos fixe
A new approach for the ortho-positronium lifetime determination in a vacuum cavity
Currently, the experimental uncertainty for the determination of the
ortho-positronium (o-Ps) decay rate is at 150 ppm precision; this is two orders
of magnitude lower than the theoretical one, at 1 ppm level. Here we propose a
new proof of concept experiment aiming for an accuracy of 100 ppm to be able to
test the second-order correction in the calculations, which is ppm. The improvement relies on
a new technique to confine the o-Ps in a vacuum cavity. Moreover, a new method
was developed to subtract the time dependent pick-off annihilation rate of the
fast backscattered positronium from the o-Ps decay rate prior to fitting the
distribution. Therefore, this measurement will be free from the systematic
errors present in the previous experiments. The same experimental setup
developed for our recent search for invisible decay of ortho-positronium is
being used. The precision will be limited by the statistical uncertainty, thus,
if the expectations are fulfilled, this experiment could pave the way to reach
the ultimate accuracy of a few ppm level to confirm or confront directly the
higher order QED corrections. This will provide a sensitive test for new
physics, e.g. a discrepancy between theoretical prediction and measurements
could hint the existence of an hidden sector which is a possible dark matter
candidate.Comment: 12 pages, 8 Figures, prepared for the proceedings of the PSAS2018
conference, Vienna (Austria
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