Experimental Test of the Pion-Nucleon Forward Dispersion Relations at High Energies

Properties of theωmeson at finite temperature and density

“…As these authors point out the real part at threshold is quite uncertain, even as regards sign. At the highest energy we consider the ratio of the real to the imaginary part agrees quite nicely with the πN data [12,13]. However this is to be expected since in I the high energy Regge behavior was fixed by using the charge-averaged πN data.…”

Nuclear incoherent photoproduction ofπ0andηfrom 4 to 12 GeV

“…The differential cross sections for the elastic π +(−) p → π +(−) p scattering at several pion momenta are presented in Fig. 10 in comparison with the available data [53][54][55]. The data at extreme forward angles [55] show an enhancement due to the Coulomb exchange, which is not taken into account in Eq.…”

πN charge-exchange forward scattering at high energies

“…Furthermore the errors of Ref. [13] do not yet include the uncertainty following from the arbitrariness of the parametrization [14].--Of course a possible discrepancy could be due to a violation of charge-independence. In order to show that the discrepancy is serious if ~=0.68 is correct, we have calculated a prediction from the dispersion relation (3.1), inserting our interpolation of the total cross sections at low energies and a smooth transition to the Serpuchov fit, using this fit up to infinity.…”

“…* The test of the dispersion relation with charge-exchange data is more stringent than that with n+p scattering data in the Coulomb interference region [13], since the number of data is much larger and the real part is not only seen in a small interference, it contributes more than 50% of the measured quantity. Furthermore the errors of Ref.…”