STUDY OF THE PIONIC CORRELATIONS IN (P)OVER-BAR-N-]2-PI(+)3-PI(-) ANNIHILATION AT REST

摘要

The experimental 2 pi correlations in (p) over bar n --> 2 pi(+)3 pi(-) annihilation at rest are studied as a function of the four-momentum transfer Q(2). The distributions have maxima at Q(2) = 0 GeV2/c(2) with height h(2) similar to 4 for both 2 pi(+) and 2 pi(-) correlations. This value is too high to be in agreement with the theory of the Bose-Einstein correlations. The experimental correlations are satisfactorily reproduced by the channel S-0(1390)pi(-), S-0(1390) being a 0(++) state decaying rho rho and sigma sigma. (sigma is the S-wave, I = 0 pi pi interaction.) The study of the predictions of this channel proves that the peak height is due to the contribution of two mechanisms having about the same strength: one is Bose-Einstein statistics, the other is the sigma sigma-rho(0) rho(0) interference. The 3 pi(-) correlations are also reported and discussed. [References: 22]