[en] The distribution of ⁴²K between plasma and erythrocytes was studied in vitro, and indicated that in media containing ca. 600-900μg/100ml ammonia, the NH₄-ion enhances the passive diffusion of K⁺ from the erythrocytes but does not interfere with active k⁺ influx. In vivo studies aimed to establish the factor responsible for the fall of potassium level with rising ammonia concentration in the blood. Slow intravenous infusion for 4 hrs of a dilute ammonium acetate solution caused the blood ammonia level to rise to 800μg/100ml average value, while the blood level of ⁴²K decreased significantly. Rise of blood ammonia was followed by decreased saliva secretion and markedly increased diuresis. The presence of ca. 800μg/100ml ammonia in the blood does not appear to interfere with the active ingression of K⁺ into the cells but results in increased K⁺-elimination in urine and decreased discharge into the rumen with the saliva. The decrease in erthrocyte K⁺ content may be considered a passive process, due to equalization of plasma and cellular concentration gradients

[en] The water and electrolyte content of the rumen which gives the 15% of the water space of the body has an important role in the regulation of the water and electrolyte metabolism of the sheep. The diuresis is very important in the standardization of the volume of the body-water space but in the ruminant the saliva secretion is also a significant-factor in the water and electrolyte metabolism of the body. In our experiments the mechanism of the regulation of the water and electrolyte metabolism was examined in two points of view. In one hand the range of the ion transport was determined in vitro in the sheep's erythrocytes of low and high K⁺ content. On the other hand in 3 in vivo experiments the function of water and salt metabolism was examined during saline overcharge by animals supplied with different quantity of saline and water and the alterations of Na⁺ and K⁺ concentrations of plasma and saliva, moreover the saliva secretion and the diuresis rates were studied

[en] The state selective (n,l) cross sections for antiproton-capture as a function of impact energy are calculated for ³He and ⁴He using the CTMC technique. A three-body CTMC method is used. The potentials representing the interactions between the components of the collision system, the case of Coulomb effective potential (Model 1) and the Garvey-type model potential (Model 2) are considered. (R.P.)

[en] Complete text of publication follows. The ASACUSA collaboration has continued the laser spectroscopy studies of antiprotonic helium atoms (p-bar - e^- - He²⁺ ≡ p-barHe⁺) at the Antiproton Decelerator (AD) of CERN. In previous years, we could measure the wave-lengths of several transitions between different energy levels of antiprotonic helium with a precision of ∼100-ppb (10^-7) each. Using our data and the antiprotonic charge/mass ratio measured previously to a very high precision by the TRAP collaboration, we could extract the best baryonic CPT (Charge-Parity-Time invariance) limit of δ = (q_p + q_p-bar)/q_p qp (m_p - m_p-bar)/m_p = 10 ppb, where q_p(p-bar₎ and m_p(p-bar₎ are the proton (antiproton) charge and mass, respectively. In 2004, we could further increase the accuracy of our measurements, thanks to the following improvements:Instead of a pulsed dye laser, we used a continuous-wave (CW) titanium-sapphire or dye laser with a frequency bandwith of < 10^-10. The CW light was then amplified to a high-energy pulse using a pulsed Nd:YAG laser.The frequency of the CW laser was measured with a femtosecond optical comb generator with a relative accuracy of ∼10^-12. The CW laser was locked to the comb generator, and their frequencies were swept across the p-barHe⁺ resonance lines.Even though the frequency of the CW laser is accurately measured using the comb generator, the frequency of the pulse-amplified light is in general different from the input frequency. This frequency shift is called 'chirp'. To compensate for this, we used an electro-optic modulator. In addition, we recorded for each laser shot the beat note between the pulse-amplified laser light and the 400-MHz-shifted CW laser. The Fourier analysis of this beat note reveals the chirp, which was usually ±20 MHz in our case. After correction with this shift, the remaining uncertainty due to the chirp is reduced to ∼1 MHz, which corresponds to a relative precision of ∼10^-9. The pulse length τ_w of the amplifying Nd:YAG laser was increased with an optical delay line by a factor 10, so as to improve the Fourier limit 1/(2πτ_w). One of the twelve transitions we measured was a metastable-to-metastable transition. Such transitions, unlike the metastable-to-short-lived transitions measured so far, have a much smaller linewidth. Besides, the accuracies of the three-body QED calculations are higher for transitions with smaller widths. So far, experimental errors and the scatter of the theoretical values have been all about 100 ppb. With our 2004 results, the differences between the two sets of calculations have become the dominant error source when we deduce the proton-antiproton mass and charge CPT limits. When we finish analyzing our data and theorists finish updating their calculations, we hope to be able to determine the antiproton mass and charge to ∼1ppb. (author)

No abstract available

[en] The ASACUSA collaboration at CERN-AD has recently submitted a proposal to measure the hyperfine splitting of the ground state of antihydrogen in an atomic beam line. The spectrometer will consist of two sextupoles for spin selection and analysis, and a microwave cavity to flip the spin of the antihydrogen atoms. Numerical simulations show that such an experiment is feasible if ∼200 antihydrogen atoms per second can be produced in the ground state, and that an accuracy of better than 10^-7 can be reached. This measurement will be a precise test of the CPT invariance.

[en] Full text: The hydrogen atom is one of the most extensively studied atomic systems, and its ground state hyperfine splitting (GS-HFS) of ν_HFS = 1.42 GHz has been measured with an extremely high precision of δν_HFS/ν_HFS ∼ 10^-12. Therefore, the antimatter counterpart of hydrogen, the antihydrogen atom, consisting of an antiproton and a positron, is an ideal laboratory for studying the CPT symmetry. As a test of the CPT invariance, measuring ν_HFS of antihydrogen can surpass in accuracy a measurement of the 1S-2S transition frequency proposed by other groups. In fact, it has several advantages over a 1S-2S measurement. Firstly, it does not require the (neutral) antihydrogen atoms to be trapped. Secondly, the only existing consistent extension of the standard model, which is based on a microscopic theory of CPT and Lorentz violation, predicts that νHFS should be more sensitive to CPT violations. In addition, the parameters introduced by Kostelecky et al. have the dimension of energy (or frequency). Therefore, by measuring a relatively small quantity on an energy scale (like the 1.42 GHz GS-HFS splitting), a smaller relative accuracy is needed to reach the same absolute precision for a CPT test. This makes a determination of νHFS with a relative accuracy of 10^-4 competitive to the measured relative mass difference of K⁰ and ^--K⁰ of 10^-18, which is often quoted as the most precise CPT test so far. The ASACUSA collaboration at CERN's Antiproton Decelerator (AD) has recently submitted a proposal to measure νHFS of antihydrogen in an atomic beam apparatus similar to the ones which were used in the early days of hydrogen HFS spectroscopy. The apparatus consists of two sextupole magnets for the selection and analysis of the spin of the antihydrogen atoms, and a microwave cavity to flip the spin. This method has the advantage that antihydrogen atoms of temperatures up to 150 K, 'evaporating' from a formation region, can be used. Numerical simulations show that such an experiment is feasible if ∼ 100 antihydrogen atoms per second can be produced in the ground state, and that an accuracy of better than 10^-6 can be reached within reasonable measuring times. (author)

[en] The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, consisting of a cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of ∼10^-7. The first preliminary measurements of the hyperfine transitions will start in 2011.

[en] Laser spectroscopy studies of antiprotonic helium atoms (p-bar-e^- - He²⁺ ≡ p-barHe⁺) were carried out at the Antiproton Decelerator (AD) of CERN. The experiments used both the direct AD antiproton beam (energy: 5.3 MeV) and the decelerated beam (energy: 20-120 keV). The objectives of the studies are summarized. (R.P.)

[en] Using two equipment, the following experiments have been made: High-precision measurements of the wavelengths of transitions between five pairs of metastable and short-lived antiprotonic states in low-density (0.1-5 mbar) ⁴He and ³He. The measurements at low densities (<1 mbar) revealed that the average lifetime of antiprotons (which can be deduced from the average decay rate of the delayed annihilation time spectra) increases to ∼5 microseconds compared to 3.5 microseconds at higher densities (>100 mbar). Four new laser resonant transitions were discovered between antiprotonic states, one in ⁴He and three in ³He. (R.P.)