Search for theSMeson

Measurements of the antiproton-proton annihilation cross-section in the beam momentum range between 180 and 600 MeV/c

“…The five data given below are not directly comparable with the present result: Hamilton et al [8] measured the charged annihilation cross-section between 350 and 1070 MeV/c. This cross-section contains the elastic antiproton scattering at angles greater than 38 ~ in the laboratory, as well as recoil protons with sufficient momentum to escape from the target (>250 MeV/c).…”

“…Brando et al [-14] measured the charged annihilation cross-section between 300 and 590 MeV/c. It has been normalized to the results from the earlier measurements [6][7][8].…”

“…The annihilation cross-section around 500 MeV/c has been measured several times [4,[6][7][8][9][10][11][12][13][14] in order to search for the X(1935) (formely S) resonance [15,16], but the measurements below 300 MeV/c are scarce and inaccurate [17][18][19][20]. This was due to the poor quality of antiproton beams at low momenta, before LEAR.…”

Multichannel effective range approach to low energy nucleon-antinucleon interactions

“…It was observed as a peak in both total and annihilation cross sections of the p/5 interactions [17,[24][25][26][27][28] and the existence of a rather narrow S-resonance seemed to be established. However, other experiments did not confirm the existence of enhancement in the S-region in total cross sections.…”

Systematic effects in the determination of the πNN coupling from differential cross section

“…R.P. Hamilton et al [19] have performed a dedicated absolute measurement of the integrated charge exchange cross section with energy in small steps. By interpolation between 596 and 608 MeV/c this corresponds to a value of σ tot = 11.80(11) at 601 MeV/c.…”