Antihydrogen Formation in Low Energy Collision of Positron with Antiproton
S. Bhattacharyya
Gokhale Memorial Girls' College, Calcutta-700 020, India
Received: May 4, 1993; revised version: March 16, 1994
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In the present paper two-body radiative recombination rate for the production of antihydrogen (H̅) in a merged beam of slow positrons (e+) and antiprotons (p¯) is studied in the light of a two-step process, which consists of capture in an excited state of H̅ with subsequent decay to the ground state and emission of a photon. Computation is done using the field theory and the Coulomb gauge. Importance of the two-step radiative recombination process relative to the well-known spontaneous photorecombination process, on the two-body radiative recombination rate for antihydrogen formation, is discussed. The present result predicts higher contribution from the two-step radiative recombination process as compared to the spontaneous photorecombination process to the rate of cold antihydrogen formation with the relative collision energy below 0.01 Rydberg, near which experiments are being conducted. However, above 0.1 Rydberg the spontaneous photorecombination process dominates over the two-step radiative recombination process. The present result is valid, as well, for the formation of hydrogen atom due to collision between slow electron and proton.
DOI: 10.12693/APhysPolA.86.297
PACS numbers: 39.10.+x, 34.50.+a, 34.70.+e