π−−pElastic Scattering at 310 MeV: Differential Cross Section and Recoil-Proton Polarization

Abstract

RICHARD FRIEDBERGSince the parameter b in (IS) approaches 1 as the electron energy approaches its maximum TFo-w" 2 /2m M , the relative sensitivity of /* decay to a and m v is different from that of processes (3) and (4). To take the example of the last paragraph but one, if a-0 and 7w"=1.6 MeV, the parameter b would affect both the energy spectrum and the asymmetry, for electron energies near the maximum, by an amount that might be observed by an improvement of existing measurements. But if 0=0.02 and m"=0, the parameter a 2 in (15) would be quite negligible. Thus, an improved measurement of the tail of the electron spectrum in ju decay might be combined with a measurement of the branching ratios for (3) and (4) to give an estimate of both a and m v .The preceding considerations are theoretical. In the immediate future, however, there is little hope of observing reactions (3) and (4) unless the branching ratio Rz/Ri is at the least 0.01. Such a large effect could not be produced by m v alone and could only be interpreted as evidence that a 2 >0. Indeed, it is known from the energy-momentum balance in ir-y. decay 6 that 6 W.

Measurement and isobar-model analysis of the doubly differential cross section for the. pi. /sup +/ produced in. pi. /sup -/p. -->. pi. /sup +/. pi. /sup -/n

“…x / v f°r tne " beams varied from 0.05 to 3.82. The larger x reflect variations, which are not understood, of about 2% from the predicted angular distributions at forward and backward angles.Figs [28][29][30]. show that the measured angular distributions were lower than SCATPI's predictions at forward angles and higher at backward angles.…”

Measurement of the polarization parameter in π^±p scattering from 356 to 519 MeV/c.

“…Input includes From Eqs. 2 and 3, this expression is a function of the polarization parameter P (8). We now make the simplifying approximation of "equal weighting".…”

“…There are four observables which completely describe 0-1/2 scattering: the differential crosssection 1. (8), the polarization parameter P (9), and the two spin rotation parameters A(6) and R (8). The polarization para meter is defined to be the polarization of the outgoing spin-1/2 particle when the initial state spin-1/2 particle is unpolarized.…”