π−pElastic Scattering at 2.26GeVc

Abstract

The elastic scattering of negative pions on protons at 2.26 GeV/c has been studied using the Lawrence Radiation Laboratory 72-in. hydrogen-filled bubble chamber. The elastic scattering cross section is found to be 8.91 =b 0.24 mb. The forward diffraction peak is well fitted by an exponential in the square of the four-momentum transfer, and the slope is found to be 8.8±0.1 GeV~2. The differential cross section is parametrized in terms of three models: optical, strong-absorption, and two-slope. It is found that the twoslope model affords the best description of the data and also does very well in predicting the polarization data of other experiments. The best-fit parameters for all three models are given. In addition, the amplitudes associated with the best fits are given for the strong-absorption and the two-slope models.

Single-Pion Production inπ−pInteractions at 2.26 GeV/c

“…A careful study revealed that the exclusion of these events from the data introduced no biases and they were deleted. 28 A fiducial volume restriction removed 740 events from our sample, leaving a total of 13 786 two-prong events for further analysis.…”

“…A discussion of the assignment of events to reaction (1) has been given elsewhere. 28 In addition, 438 events were classified as associated production events on the basis of topology, PACKAGE output information, and ionization. The remaining events were considered to fit either hypothesis (2) or (3) (or both) if they had a X 2 probability >0.1%.…”

“…17 is based on an OPE A calculation using data from our elastic scattering experiments. 28 Hence, the shape of the curve is in no way influenced by the bias in the first two intervals. In Figs.…”

“…These curves were calculated at this energy using a fit to our elastic scattering data. 27,28 The initial-state absorption parameters resulting from this fit were C+=0.827 and Y + = 0.065. The final-state absorption parameters were chosen to be C_=1.0 and 7_=f7 + .…”

“…30 A detailed account of the elastic scattering bias corrections has been given elsewhere. 28 A similar procedure was used to correct the number of type-(2) events. The cross sections for each two-prong final state and for the other topologies are given in Table I.…”