LEAP 2013 Uppsala SE

Frozen microspheres of hydrogen, so called pellets, are used as targets in the hadron physics experiment WASA (Forschungszentrum Juelich, Germany) [1] and will also be used in the future PANDA experiment at FAIR (GSI, Darmstadt, Germany) [2]. Pellets have a diameter of 25-30 micrometers. They are generated 2 - 3 meters above the interaction region, to which they travel inside a thin pipe...

During the past decades the nuclear and optical experiments to detect parity nonconservation (PNC) and hyperfine (hf) structure have progressed to the point where PNC amplitudes can be measured with accuracy on the level of a few % in certain heavy isotopes and significantly worse in some nuclei [1, 2]. Nowadays the PNC in the finite Fermi-systems has a potential to probe new physics beyond...

Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the AD, but will be particularly important for the future ELENA ring and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and...

Hydrogen Lyman-α radiation (121.56 nm) is important because it allows for the excitation and detection of ground-state antihydrogen atoms by a one-photon process. The trapping of antihydrogen, recently reported by the ALPHA collaboration at CERN, has revived interest in Lyman-α lasers. In order to perform high precision tests of matter-antimatter symmetry violations or gravity-antimatter...

At temperatures and densities relevant to current experiments antihydrogen is mainly formed through the three-body process pbar + e+ + e+ -> Hbar + e+. The state formed initially through this process is a Rydberg state, usually with a binding energy of only a few Kelvin. This state is fragile, and will not survive interaction with external fields or other particles, unless it is first...

A nonadiabatic description of the hydrogen-antihydrogen scattering is presented. The collisions are treated within the Coupled Rearrangement Channels method, which allows us to include different possible arrangement channels of the system under consideration. More over the proper asymptotic form of the continuum wave function is ensured, while the inner part of the wave function can still...

Advancements in trapping and cooling antihydrogen pave a way to accurate spectral and gravitational measurements. Analysis of experiments require detailed knowledge and understanding of the nonlinear dynamics of antihydrogen atoms in magnetostatic traps in the presence of gravity. Perturbation theory yields insights and detailed simulations used to evaluate various techniques for measuring the...

We investigate the presence of thermodynamic instabilities in a hot and dense nuclear medium where a phase transition from a gas of massive hadrons to a nearly massless baryon, antibaryon plasma can take place. The analysis is performed by requiring the global conservation of baryon number and zero net strangeness in the framework of an effective relativistic mean field theory with the...

for the PANDA collaboration. The creation mechanism of quark-antiquark pairs and their arrangement to hadrons can be studied by measuring the reactions of the type antiproton+proton -> antibaryon+baryon. According to the Okubo-Zweig-Iizuka rule, all processes with disconnected quark lines are suppressed. By comparing several reactions involving different quark flavours the OZI rule, and its...

A relativistic operator approach, based on the unified operator perturbation theory and relativistic energy formalism [1], is applied for studying resonant phenomena in the low-energy heavy-nuclei collisions accompanying the electron-positron pair production (EPPP) process and treating the compound nucleus in an extreme electromagnetic (electric) field. As it is known, a narrow e+ line in...

The ASACUSA collaboration aims to measure the ground state hyperfine splitting of anti hydrogen with a Rabi like experiment. In the experimental setup a beam of partially polarized anti hydrogen atoms enter a microwave cavity which induces a spin flip. After that a superconducting sextupole magnet is used to analyze the spins of the particles. Finally our anti hydrogen detector identifies the...

The PANDA (AntiProton ANnihilation at DArmstadt) experiment is one of the key projects at the future Facility for Antiproton and Ion Research, which is currently under construction at GSI, Darmstadt. The PANDA experiment will perform precise studies of antiproton-proton annihilations and reactions of antiprotons with nucleons of heavier nuclear targets. Particles emitted at angles covering the...

The eta meson production process can be studied via measurements of the analyzing power, Ay, which may be understood as a measure of the relative deviation between the differential cross section with and without polarized beam. So far, these observables have been determined only for a few excess energies and with very low statistics. Therefore, the measurement of the (vec)pp->pp eta reaction...

The central electromagnetic calorimeter (EMC) of the PANDA detector consists of a barrel part with 11 360 PWO crystals of 11 different shapes, a forward end cap with 3864 crystals and a backward end cap with 592 crystals. The complete EMC will sit in a solenoid field, which rules out the use of photomultiplers as light sensors. Avalanche Photo Diodes (APDs) will be used for the barrel part to...

The principal aim of the ALPHA experiment at CERN is to trap cold atomic antihydrogen, study its properties, and, ultimately, perform precision comparison between hydrogen and antihydrogen atomic spectra. Recently, several important milestones have been achieved, including long confinement times of antihydrogen atoms, the first spectroscopic measurements of the antihydrogen atoms and first...