Unified treatment of hadronic annihilation and protonium formation in slow collisions of antiprotons with hydrogen atoms

作者：Sakimoto Kazuhiro^*

来源：Physical Review A, 2013, 88(1): 012507.

DOI：10.1103/PhysRevA.88.012507

Antiproton ((p) over bar) collisions with hydrogen atoms, resulting in the hadronic process of particle-antiparticle annihilation and the atomic process of protonium ((p) over barp) formation (or (p) over bar capture), are investigated theoretically. As the collision energy decreases, the collision time required for the (p) over bar capture becomes necessarily longer. Then, there is the possibility that the (p) over bar -p annihilation occurs significantly before the (p) over bar capture process completes. In such a case, one can no longer consider the annihilation decay separately from the (p) over bar capture process. The present study develops a rigorous unified quantum-mechanical treatment of the annihilation and (p) over bar capture processes. For this purpose, an R-matrix approach for atomic collisions is extended to have complex-valued R-matrix elements allowing for the hadronic annihilation. Detailed calculations are carried out at low collision energies ranging from 10(-8) to 10(-1) eV, and the annihilation and the (p) over bar capture (total and product-state selected) cross sections are reported. Consideration is given to the difference between the direct annihilation occurring during the collision and the annihilation of (p) over barp occurring after the (p) over bar capture. The present annihilation process is also compared with the annihilation in two-body (p) over bar + p collisions.

• 出版日期2013-7-12