Absolutepp-elastic cross sections from 492 to 793 MeV

Abstract

Absolute pp-elastic-differential cross sections were measured at incident energies 492, 576, 642, 728, and 793 MeV from about 30' to 90' c.m. The total uncertainty was determined to be less than 170, made possible by particle counting for beaxn normalization and extensive cross-checks of systematic eQects. These new data are consistent with previous data above 600 MeV but have uncertainties about a factor of 10 smaller. Near 500 MeV these data are consistent with 90' data from TRIUMF, but differ signi6cantly from similar data from PSI; the cause of this discrepancy is discussed.PACS number(s): 25.40.Cm, 25.10.+s 'Present address:

πNNcoupling constants fromNNelastic data between 210 and 800 MeV

“…Here we estimate a systematic error of ±1%, for reasons we shall now detail. From 500 to 800 MeV, recent measurements of Simon et al [18] have statistical errors of ±0.5% and an absolute accuracy of about ±0.5%. From 500 to 580 MeV, there are similarly precise data of Chatelain et al [19], and from 300-500 MeV precise 90 • data of Ottewell et al [20] with normalisation errors of ±1.8%.…”

“…where M is the mass of the proton and µ c the mass of the charged pion, this value of f 2 corresponds to g 2 = 14.28 (18). This determination, based on the fixed t dispersion relations for the B (+) amplitude in πN elastic scattering, refers to exchange of charged pions at the nucleon pole: π − p → n. Since 1987, the Nijmegen group has challenged this value in a series of papers [2][3][4], analysing NN elastic data up to 350 MeV with a potential model.…”

The legacy of the experimental hadron physics programme at COSY

“…integral of the precise LAMPF measurements at T p = 793 MeV [72], values of the pp elastic differential cross section could be obtained from 230 to 2590 MeV with a 1% overall systematic uncertainty. In total about 4 × 10 7 good pp elastic scattering events were registered and so the statistical uncertainties were also very low.…”

Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

“…They are, with a few exceptions [8][9][10], angular distributions for discrete energies whose uncertainties of relative normalization [11] will propagate through phase shifts into the resulting nucleon-nucleon potentials [12]. Above that, the database grows increasingly sparse, even for spin averaged cross sections.…”

“…Absolute normalization is established at p p 1455 MeV͞c with reference to the angular distribution measured by Simon et al [11] in an external experiment with 1% total uncertainty. Figure 3 shows the good agreement of our cross sections for the interval Q c.m.…”