Abstract
We propose to measure the two-photon capture mode of pionic hydrogen using the RMC [1] pair spectrometer at the TRIUMF cyclotron. Currently, only an experimental upper limit of B.R. ≤ 5.5 × 10-4 is available for the γγ capture mode [2]. Our new data will critically test the theoretical calculations and the intriguing predicted dominance of the ππ → γγ annihilation graph. More speculatively, since crossing symmetry relates ππ → γγ to γπ → γπ, this threshold reaction may be a novel probe of the pion's electric polarizability. We show results of our 1997 engineering run and Monte Carlo studies for the two-photon capture mode of pionic hydrogen and carbon. We also present our preliminary upper limit for the B.R. [π-p → γγn] ≤ 2.8 × 10-4.
Original language | English |
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Pages (from-to) | 3149-3152 |
Number of pages | 4 |
Journal | Acta Physica Polonica B |
Volume | 29 |
Issue number | 11 |
State | Published - 1998 |
Externally published | Yes |