Martin Suffert

Evidence for narrow bound states related to the pp system

Abstract The γ-ray spectrum accompanying the p p annihilation at rest has been measured with a large NaI(Tl) spectrometer. Three γ-lines have been observed with energies of 183 ± 7 MeV, 216 ± 9 MeV, and 420 ± 17 MeV at confidence levels of 99.0%, 97.5%, and 98.2%, respectively. The width of the lines corresponds to the detector resolution.

Proton-antiproton annihilations at rest into π0ω, π0η, π0γ, π0π0, and π0η′☆

Proton-antiproton annihilations at rest in liquid hydrogen were investigated through the inclusive γ spectrum, related to the annihilation. The high-energy part of the spectrum was used to deduce branching ratios for the so far unobserved annihilation channels: R(pp→π0ω) = (2.38 ± 0.65)%, R(pp→ π0η) = (0.82 ± 0.10%, Rpp→π0γ) = (0.015 ± 0.007)%, and R(pp → π0π0 = (0.06 ± 0.04)%. An upper limit for the π0η′ channel was deduced to be R(pp → π0η′) < 1.1%.

3H(p,γ)4He reaction from 3 TO 18 MeV

Abstract The 3 H(p,γ) 4 He cross section has been measured at 90° from 3 to 18 MeV proton energy, at 0° from 4 to 14 MeV, and complete angular distributions were taken at 10.5, 12 and 14 MeV. The c.m. angular distributions are consistent with A + B sin 2 θ + C sin 2 θ cos θ + D sin 2 θ cos 2 θ as expected for mixed E1 and E2 radiations. Using our and other results, the integrated 4 He(γ,p) 3 H cross section, computed from the reciprocity relation, is decomposed into E1 and E2 contributions up to E γ ∼ 30 MeV. Extrapolations for the relative contributions are proposed up to E γ ∼ 150 MeV. After removal of kinematic factors, the E1 contribution is shown to be resonant, but the E2 contribution is not resonant. Interpretation of the coefficient ratio A B by Crone and Werntz shows that M2 contributions have an important effect on the magnitude of this coefficient. If the 4 He level scheme of Werntz and Meyerhof is accepted, the singlet strength in the two T = 1,1 − levels appears to lie predominantly in the lower level, in contrast to findings from 3 He(p, p) scattering and polarization measurements.

Remeasurement of the magnetic moment of the antiproton

AbstractA high-precision measurement of the finestructure splitting in the circular 11→10 X-ray transition of

Precision measurement of strong interaction isotope effects in antiprotonic 16O, 17O, and 18O atoms

\bar p^{208} Pb

Reactions 12C(α, n)15O and 12C(α, p)15N

was performed. The experimental value of 1199(5) eV is in agreement with QED calculations. From that value the magnetic moment of the antiproton was deduced to be −2.8005(90)μnucl. With this result the uncertainty of the previous world average value was reduced by a factor of ≈2. A comparison with the corresponding quantity of the proton now yields:

Strong interaction effects in antiprotonic 6Li/7Li atoms

{{\left( {\mu _p - \left| {\left\langle {\mu _{\bar p} } \right\rangle } \right|} \right)} \mathord{\left/ {\vphantom {{\left( {\mu _p - \left| {\left\langle {\mu _{\bar p} } \right\rangle } \right|} \right)} {\mu _p }}} \right. \kern-\nulldelimiterspace} {\mu _p }} = \left( { - 2.4 \pm 2.9} \right) \times 10^{ - 3}