Some properties of the psi(3.7) resonance, and features of the total hadronic cross section in e$sup +$e$sup -$ annihilation from 2.4 GeV to 5.0 GeV c.m. energy Page: 3 of 19

                                
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Although the e e decay mode of the *I was difficult to separate fro the
dominant t-channel Bhabha background, as well as fro the V electron decay
cede, the p- mode was tore easily isolated, as will be seen. Subtracting
the fED background, the branching ratio to euoMs Ls found:
alt) -   0.03  0.003 -
If we asc-ee p-o universality ad the spin assigaent J = 1, then the
widths are determined
re(*') . 2.2 0.5 keV
2WD keV < f(*, ) < 500 keV.
The electron width determination is nearly independent of the lepton ratio,
because the latter is so email, and the snore on r reflect just the
ucertainty of f a    dW. The large uncertainty in the limit an the total
width cones about partly from the background subtraction, which is reflected
in the p p branching ratic, but also from the possible -out:bution due to
interference with the QED amplitude. The presence or extent of the inter-
ference has not yet been investigated in detail eperintally. The eapec-
tation is to obtain a much more precise determination of these quantities
when ore data is collected The position of the peak is kawn ore accu-
rately than originally, due to recalibration of a flip coil used to deter-
mine the PElR magnetic guide field. The new value is 3.684   0. C)5 reV.
It should be noted that the 1', althogh very nrrow, ecs to be natkedly
broader than the #.
Let us now eanine c more detail the decay
the rode by which this cascade decay was dlscooveed. Pron a sa-le of about
3D1J0 ewnts, the missing nass distribution shown in Fig. 3 was obtained,
showing conclusive evidence for decay (1). The branching ratio for decay
by (1) was deterined, after suitable efficiency correctios and background
subt-astin: