Abstract
A search for narrow, deeply bound pionic atom states via atomic radiative capture of negative pions in a target of [Formula Presented]Pb was carried out for pion kinetic energies of 20 and 25 MeV. Although no clear signature of any such gamma ray emission could be observed in the data, fits of the gamma ray spectra between the energies of 12 and 42 MeV involving a quadratic background together with a pair of peaks [Formula Presented], [Formula Presented] whose relative intensity was taken from theory yielded an overall strength for the peaks which are consistent (to a 67% confidence level) with radiative capture whose integrated cross section is 20.0 [Formula Presented] 10.0 [Formula Presented]b/sr at 90[Formula Presented] for 20 MeV incident pions. A lower probability (40% confidence level) result was obtained when the fit was carried out without the peaks included, just the continuum background.
Original language | English |
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Pages (from-to) | 2492-2500 |
Number of pages | 9 |
Journal | Physical Review C - Nuclear Physics |
Volume | 55 |
Issue number | 5 |
DOIs | |
State | Published - 1997 |