140 research outputs found
An atomic hydrogen beam to test ASACUSA's apparatus for antihydrogen spectroscopy
The ASACUSA collaboration aims to measure the ground state hyperfine
splitting (GS-HFS) of antihydrogen, the antimatter pendant to atomic hydrogen.
Comparisons of the corresponding transitions in those two systems will provide
sensitive tests of the CPT symmetry, the combination of the three discrete
symmetries charge conjugation, parity, and time reversal. For offline tests of
the GS-HFS spectroscopy apparatus we constructed a source of cold polarised
atomic hydrogen. In these proceedings we report the successful observation of
the hyperfine structure transitions of atomic hydrogen with our apparatus in
the earth's magnetic field.Comment: 8 pages, 4 figures, proceedings for conference EXA 2014 (Exotic Atoms
- Vienna
On the characterisation of a Bragg spectrometer with X-rays from an ECR source
Narrow X-ray lines from helium-like argon emitted from a dedicated ECR source
have been used to determine the response function of a Bragg crystal
spectrometer equipped with large area spherically bent silicon (111) or quartz
(10) crystals. The measured spectra are compared with simulated ones
created by a ray-tracing code based on the expected theoretical crystal's
rocking curve and the geometry of the experimental set-up.Comment: Version acceptee (NIM
Performances of an Active Target GEM-Based TPC for the AMADEUS Experiment
In this paper, we present the R & D activity on a new GEM-based Time Projection Chamber (GEM-TPC) detector for the inner region of the AMADEUS experiment, which is aiming to perform measurements of low-energy negative kaon interactions in nuclei at the DAΦNE e+ e- collider at LNF-INFN. A novel idea of using a GEM-TPC as a low mass target and detector at the same time comes motivated by the need of studying the low energy interactions of K- with nuclei in a complete way, tracking and identifying all of the produced particles. Even more, what makes the experimental proposal revolutionary is the possibility of using different gaseous targets without any other substantial intervention on the experimental setup, making it a flexible multipurpose device. This new detection technique applied to the nuclear physics requires the use of low-radiation length materials and very pure light gases such as Hydrogen, Deuterium, Helium-3, Helium-4, etc. In order to evaluate the GEM-TPC performances, a 10 × 10 cm2 prototype with a drift gap of 15 cm has been realized. The detector was tested at the πM1 beam facility of the Paul Scherrer Institut (PSI) with low momentum pions and protons. Detection efficiency and spatial resolution, as a function of gas mixture, gas gain and ionazing particle, are reported and discussed
Development of a GEM-TPC prototype
The use of GEM foils for the amplification stage of a TPC instead of a con-
ventional MWPC allows one to bypass the necessity of gating, as the backdrift
is suppressed thanks to the asymmetric field configuration. This way, a novel
continuously running TPC, which represents one option for the PANDA central
tracker, can be realized. A medium sized prototype with a diameter of 300 mm
and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using
a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector
test under realistic experimental conditions should allow us to verify the
spatial resolution for single tracks and the reconstruction capability for
displaced vertexes. A series of physics measurement implying pion beams is
scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como
(italy
Microwave spectroscopic study of the hyperfine structure of antiprotonic helium-3
In this work we describe the latest results for the measurements of the
hyperfine structure of antiprotonic helium-3. Two out of four measurable
super-super-hyperfine SSHF transition lines of the (n,L)=(36,34) state of
antiprotonic helium-3 were observed. The measured frequencies of the individual
transitions are 11.12548(08) GHz and 11.15793(13) GHz, with an increased
precision of about 43% and 25% respectively compared to our first measurements
with antiprotonic helium-3 [S. Friedreich et al., Phys. Lett. B 700 (2011)
1--6]. They are less than 0.5 MHz higher with respect to the most recent
theoretical values, still within their estimated errors. Although the
experimental uncertainty for the difference of 0.03245(15) GHz between these
frequencies is large as compared to that of theory, its measured value also
agrees with theoretical calculations. The rates for collisions between
antiprotonic helium and helium atoms have been assessed through comparison with
simulations, resulting in an elastic collision rate of gamma_e = 3.41 +- 0.62
MHz and an inelastic collision rate of gamma_i = 0.51 +- 0.07 MHz.Comment: 15 pages, 9 figures. arXiv admin note: substantial text overlap with
arXiv:1102.528
VIP EXPERIMENT: NEW EXPERIMENTAL LIMIT ON PAULI EXCLUSION PRINCIPLE VIOLATION BY ELECTRONS
The VIP (Violation of the Pauli Exclusion Principle) experiment is investigating one of the basic principles of modern physics, searching for anomalous X-rays emitted by copper atoms in a conductor: any detection of these anomalous X-rays would mark a Pauli forbidden transition. VIP is currently taking data at the Gran Sasso underground laboratories, and its scientific goal is to improve by three-four orders of magnitude the previous limit on the probability of Pauli violating transitions, bringing it into the 10-29÷-30 region. The new experimental results, together with future plans, are presented
Experimental test of Non-Commutative Quantum Gravity by VIP-2 Lead
Pauli Exclusion Principle (PEP) violations induced by space-time
non-commutativity, a class of universality for several models of Quantum
Gravity, are investigated by the VIP-2 Lead experiment at the Gran Sasso
underground National Laboratory of INFN. The VIP-2 Lead experimental bound on
the non-commutative space-time scale excludes -Poincar\'e far
above the Planck scale for non vanishing ``electric-like" components of
, and up to Planck scales if they are
null. Therefore, this new bound represents the tightest one so far provided by
atomic transitions tests. This result strongly motivates high sensitivity
underground X-ray measurements as critical tests of Quantum Gravity and of the
very microscopic space-time structure.Comment: 13 pages, 2 figures. arXiv admin note: substantial text overlap with
arXiv:2209.0007
VIP-2 —High-Sensitivity Tests on the Pauli Exclusion Principle for Electrons
The VIP collaboration is performing high sensitivity tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the underground Gran Sasso National Laboratory INFN (Italy). In particular, the VIP-2 Open Systems experiment was conceived to put strong constraints on those Pauli Exclusion Principle violation models which respect the so-called Messiah–Greenberg superselection rule. The experimental technique consists of introducing a direct current in a copper conductor, and searching for the X-rays emission coming from a forbidden atomic transition from the L shell to the K shell of copper when the K shell is already occupied by two electrons. The analysis of the first three months of collected data (in 2018) is presented. The obtained result represents the best bound on the Pauli Exclusion Principle violation probability which fulfills the Messiah–Greenberg rule
High Precision Test of the Pauli Exclusion Principle for Electrons
The VIP-2 experiment aims to perform high precision tests of the Pauli Exclusion Principle for electrons. The method consists in circulating a continuous current in a copper strip, searching for the X radiation emission due to a prohibited transition (from the 2p level to the 1s level of copper when this is already occupied by two electrons). VIP already set the best limit on the PEP violation probability for electrons , the goal of the upgraded VIP-2 (VIolation of the Pauli Exclusion Principle-2) experiment is to improve this result of two orders of magnitude at least. The experimental apparatus and the results of the analysis of a first set of collected data will be presented
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