We show that effects of dibaryon resonances can be clearly seen in the data on the differential cross section of red elastic scattering. Giving the formulation of the Glauber model with the resonance formation term in red direct channel in detail and analyzing all the data presently available by this model, we find that at least two resonances are needed in red direct channel in order to explain the data. One of them may be 'F, (2. 25 GeV) state of two nucleons which was found at Argonne and the other has mass value around ~.5GeV. The data are not enough to determine the spin-parity of the latter but ()' seems somewhat preferable. The branching ratios of the resonances into red system are also given. \3 l. ln trml uetionThe theoretical discussion on the existence of dibaryon resonance is ample in literature. 11 -81 There are not a few experimental evidenc.es for its existenc.e. 91~1 n The work in this field has been much intensified espec.ially by recent experiments using the polarized proton beam and target where the strong evidence of diproton states in 3 F 3 and 1 D, waves was reported. 11) -131 We expect these dibaryon resonances to give a wealth of information about hadron physics, though the nature of the dibaryon resonances has not yet been clarified. The question whether the resonances should be treated as a system of six quarks or as that of nucleon and its isobar or as the threshold effect has been discussed but is left unsettled. It seems necessary to us that properties of the dibaryon resonances should be mvestigated not only in the PP elastic scattering but also in other processes. Since the dibaryon resonance 3 F 3 has small elasticity, there remain many decay channels.It is of particular interest to study the channels including deuteron whic.h contains six quarks. The analysis of the coupling between dibaryon and deuteron might tell us the resemblance or the difference between them. The simplest of these processes is the pion deuteron elastic scattering. Other processes are less advantageous for the study of dibaryon resonances because the analysis depends on unconfirmed models, such as the Y ao modeP 41 for the reaction r.:d--'>PP, which contain the triangle diagram and the results become highly model dependent. In Ref. 15) we• hal'e poinlt'd that the clibarynn resonances r·an affe<"t the r:d elastic sc.attering and in Ref. 16) we have shown that the features of the differen-by guest on March 29, 2015 http://ptp.oxfordjournals.org/ Downloaded from § 2. Glauber amplitude In 1 his sectio11 we will derive the s-chiinnel be licit~ ampliwcle "r the ;:d elastic scattering, f 1~" using the Glauber model. by guest on March 29, 2015 http://ptp.oxfordjournals.org/ Downloaded from m the laboratory frame, where Q is the mean of the incident and outgoing momenta of the pion and ad· and b.N are written in terms of the invariant amp lit ucles A.11• and B.N as by guest on March 29, 2015 http://ptp.oxfordjournals.org/ Downloaded from :n) G. \V. Barry, Phys. Rev.

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