Selected Studies of Elastic and Radiative Two Body Decays of Charmonium.
Abstract
Running at the Stanford Linear Accelerator Center's e('+)e(') colliding beam machine SPEAR, the MARK III, a general purpose magnetic spectrometer, has collected 2.7 x 10('6) produced J/(psi)'s during the spring of 1982 and the spring of 1983. The electro magnetic decays of the J/(psi) have been studied. New results are presented on the decay J/(psi)(>)(pi)('+)(pi)('), J/(psi)( >)K('+)K(') as well as the first observation of the decay J/(psi)(>)K(,S)K(,L). Branching ratios are measured to be (1.60 (+OR) .25) x 10('4), (2.28 (+OR) .42) x 10('4) and (1.01 (+OR) .20) x 10('4), respectively. This implies the electromagnetic form. factors are then (VBAR)F(,(pi)('(+OR)))(VBAR)('2) = (.87 (+OR) .2) x 10('2), (VBAR)F(,K('(+OR)))(VBAR)('2) = (1.4 (+OR) .4) x 10('2) and (VBAR)F(,K('0))(VBAR)('2) = (.64 (+OR) .16) x 10('2). In the mode J/(psi)(>)(gamma)(mu)('+)(mu)(' ), the QED prediction is found to match the data quite well, and limits are set on the product branching ratio BR(J/(psi)(>)(gamma)(xi)(2.2)) (.) BR((xi)(2.2)(>)(mu)('+)(mu)(' )) < 8.3 x 10('6) at the 90% C.L. Also presented are results on the decay J/(psi)(>)pp with a branching ratio measured to be (1.91 (+OR) .16) x 10('3). The angular distribution is found to vary as 1 + (.56 (+OR) .14)cos('2)(theta). The decay channel J/(psi)( >)(gamma)pp has been studied. The inclusive branching ratio for J/(psi)(>)(gamma)pp is found to be BR(J/(psi)( >)(gamma)pp) = (4.89 (+OR) .49) x 10('4). Also seen is the decay J/(psi)(>)(gamma)(eta)(,c)(>)(gamma)pp and a product branching ratio is found to be BR(J/(psi)( >)(eta)(,c)) (.) BR((eta)(,c)(>)pp) = (1.4 (+OR) .7) x 10('5). Lastly, limits are set for the nonobservation of the decay J/(psi)(>)(gamma)(xi)(2.2)(>)(gamma)pp with a product branching ratio BR(J/(psi)(>)(gamma)(xi)(2.2)) (.) BR((xi)(2.2)(>)pp) < 2.0 x 10('5).
 Publication:

Ph.D. Thesis
 Pub Date:
 1984
 Bibcode:
 1984PhDT.......113B
 Keywords:

 Physics: Elementary Particles and High Energy