| タイトル | Measurements of the reaction e/+/e/-/ yielding gamma-gamma at center-of-mass energies in the range 6.2-7.4 GeV |
| 著者（英） | Liberman, A. D.; Carrington, R. L.; Hofstadter, R.; Hughes, E. B.; Beron, B. L.; Hilger, E.; Hill, W. T.; Martin, T. W.; Oneill, L. H.; Ford, R. L. |
| 著者所属（英） | Stanford Univ. |
| 発行日 | 1977-04-01 |
| 言語 | eng |
| 内容記述 | The cross section for the pair-annihilation reaction e(+)e(-) yields gamma-gamma were measured at center-of-mass energies in the range 6.2-7.4 GeV and at production angles close to 90 deg. The experimental apparatus consisted of two identical spectrometers which were set to view the luminous region at SPEAR-II from opposite directions at an azimuthal angle of 45 deg. In each spectrometer there was a NaI(TI) crystal 20 radiation lengths thick and 30 in. in diameter to measure the gamma-ray energies. Annihilation events were detected by an electronic trigger which required only the observation in coincidence of more than 0.2 GeV in each NaI(TI) crystal within + or - 15 nsec of the crossing beams. The observed rates of pair-annihilation events were found to be in agreement with those expected from quantum electrodynamics (QED) at all the center-of-mass energies used. |
| NASA分類 | NUCLEAR AND HIGH-ENERGY PHYSICS |
| レポートNO | 77A32044 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/438194 |
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