International Conference on Exotic Atoms and Related Topics - EXA2014

Producing a beam of antihydrogen, as published by the ASACUSA-Hbar collaboration[1], imposes some big experimental challenges that limit the production rate. Therefore a suitable detector needs to have very good suppression of background events. The main sources of background are upstream annihilations of antiprotons within the cusp and cosmic particles penetration the detector. These...

We are planning a missing-mass spectroscopy experiment of eta’ mesic nuclei to study in-medium effect for the eta’ meson. We will employ a 2.5 GeV proton beam from SIS18 (Heavy Ion Synchrotron) at GSI, and use the 12C(p,d) reaction to create eta’ mesic carbon nuclei. To obtain the missing-mass spectrum, the momenta of the ejectile deuterons will be measured by the FRS (Fragment Separator) used...

We report on the theoretical estimates of the density shift and broadening of selected transition lines in pionic helium evaluated in the semiclassical approach, earlier successfully applied to the calculation of the density effects in antiprotonic helium spectroscopy, These results are expected to help reduce the uncertainty of the oncoming laser spectroscopy experiments with pionic helium.

The study of the KbarN system at low energies play a key role for the understanding of the strong interaction between hadrons in the strangeness sector. Based on the development of new X-ray detectors and on the availability of the intense kaon beam line K1.8BR at J-PARC the kaonic deuterium experiment will provide the strong-interaction level shift and width of the kaonic deuterium 1s state....

Ultra-slow muons, which are positive muons having an energy of a few eV, are useful tools for producing variable-energy muon beams with extraordinarily small energy spread by accelerating them through an electrostatic field. This technique has attracted attention for extending muSR studies to thin films, surfaces and interfaces, and nano-structures, which has not yet been achieved by the...

High precision spectroscopy of trapped hydrogen molecular ions and their isotopomers opens room for new, improved-accuracy determination of fundamental constants such as the electron-to-proton and electron-to-deuteron mass ratio, the fine structure constant etc., and of their time variability. In order to understand the likely experimental uncertainties due to residual external magnetic and...

The presented analysis shows that the atom production in the p-nuclear interactions is significantly increasing if the momentum of proton Pp will change from 24 up to 450 GeV/c. If we take into account the acceptance of the DIRAC setup at CERN then for Thetalab = 4o and Pp=450 GeV/c the yields of pi+pi-, pi+K-, K+pi- and pi+pi- atoms per one proton-nuclear interaction are 17, 35 and 27 times...

In situ methods of dose verification for ion therapy are still in development. A promising approach is the measurement of prompt gamma ray emission following nuclear reactions, which can be correlated to the Bragg peak. This technique is known as prompt gamma imaging (PGI). An important topic for PGI is the ideal positioning of the detector due to low count rates. Recent simulations...

Inner-shell ionization process by positron impact is of fundamental importance to understand the collision dynamics between anti-particle and atom. Extensive experimental and theoretical investigations have been reported. At high energies the inner-shell ionization cross sections by positrons are almost same as those by electrons. On the other hand, in the case of low-energy region large...

We are planning a measuremnt of the ground state hyperfine structure of muonium at J-PARC/MLF. Muonium is a hydrogen-like bound state only consist of leptons, and its HFS is a good probe for testing QED theory. The muon mass and magnetic moment which are fundamental constants of muon have been so far determined by the muonium HFS experiment at LAMPF. The high intensity beam soon to be...

We present systematic calculations of the leading order relativistic corrections including the hyperfine splitting (HFS) for a wide range of rotational and vibrational states of the HT+ molecular ion. We also calculate the DC and AC Stark effects for the molecular hydrogen ions H2+ and HD+ in the non-relativistic approximation. The influence of the DC Stark polarizability effect on the...

Recently the CREMA collaboration(*) succeeded to measure the Lamb shift (2S-2P energy difference) in muonic hydrogen by means of laser spectroscopy, providing a ten times more accurate value for the charge radius of the proton [1,2]. This study analyzes the data sets taken with muonic hydrogen and muonic deuterium even further in order to investigate the deexcitation of the metastable...

A detector used in two different experiments of the ASACUSA collaboration at the CERN Antiproton Decelerator is presented. It is made of several modules, each one made of ~60, 1m long, scintillating bars, which allows the detection of the charged particles arising from the antiproton-nuclei annihilations. The modularity of the detector, its electronics readout and the data acquisition system,...

Charge, Parity and Time (CPT) symmetry is the most fundamental theoretical concepts in particle physics. The ASACUSA-Hbar collaboration aims to test this property by measuring the hyperfine structure in ground state antihydrogen [1]. Due to the big challenge in producing a beam of antihydrogen [2] sophisticated simulations are needed. Especially tracking of antihydrogen atoms through...

A multipass laser cavity is presented which can be used to illuminate an elongated volume from a transverse direction. The illuminated volume can have a several cm² large transverse cross section. Convenient access to the illuminated volume for other experimental components is granted at a large solid angle. The multipass cavity is very robust against misalignment, and no...

Study of Xi-N interaction is important for unified understanding of baryon-baryon interaction.NN interaction has been well studied by plenty of scattering experiments, and Lambda N interaction by spectroscopy of hypernuclei. On the otherhand, we will investigate the Xi N interaction through a Xi- atomic X-ray measurement. Energy shifts and widths of Xi atomic X rays provide information...