Study of W' Decays*

Hadronic decays of the w’ are reviewed and a new preliminary upper limit of B(~‘+pn )<7.0~10-~ at 90% C.L. from the Mark III is presented. T he I,V’ is the 23S, cc quark-antiquark vector meson and is the only well established radial excitation. The hadronic decay rate of the w’ relative to the J/v should scale as the . ratio of the three gluon widths which are proportional to the leptonic widths divided by the full widths; B(w’+ hadrons ) B(W’ + 999 1 B(J/ I,V + hadrons ) = B( J/v + ggg.) = r( J/ w + e+e-) r(yq) This predicts that the absolute branching ratios of hadronic modes of the w’ are 12% of the corresponding decay from the J/y or 8 times smaller. The Mark II groupfl] measured several decays in 1982 and observed hadronic decays into several multibody decays but none of the vector-pseudoscalar pair combinations. More recently, the Crystal Ball groupf2] observed the radiative decay to the tensor f(l270) but neither to the n nor the n’. The measured rates are shown in table 1. The second column contains the J/v branching rates and the third column the ratio of rates which should be -12%. The results are very striking. Within the errors, the missing modes are vector pseudoscalar decays whereas the other modes are roughly consistent with the factor of 8 ratio. For some unknown reason the w’ does not decay into this particular choice of mesons pairs. The largest J/I,v mode which is missing is the plr: decay Invited talk presented at the meeting of the1989 International Symposium on Heavy Quark Physics at Cornell University, Ithaca, N.Y., June 13-17. 1989 *Work supported in part by the National Science Foundation and by the Department of Energy contracts DEAC03-76SF00515,DE-AC02-76ER01195,DE-AC03-81ER40050, DE-AC02-87ER40318 and DE-AM0376SF000324