Determination of Spin and Decay Parameters of Fermion States

Abstract

There is a difference of a factor 64 between our calculation and that of Riazuddin and Fayyazuddin. We believe that the latter authors have used a wrong definition of A differing by a factor of 8 from the conventional one, so that we have to multiply their expression by 64. 8 S. Coleman and S e L. Glashow, Phys. Rev. Letters 6>, 423 (1961). Equation (13) has been also noted by E. C. G. Sudarshan (private communication). We may remark that we can estimate y by another formula, y = (l/2v r 3*)[m 2 (7r 0 ) + 3w 2 (i)) -4m 2 (K 0 )], but this gives an unreasonably large value for y (see reference 4). It might also be noted that it would not necessarily vanish in the charge-independence limit, whereas the formula used, Eq. (13), does. 9

Measurements ofψ(3686)→K−ΛΞAblikim1, Ачасов2, Ai3 et al. 2015Phys. Rev. D16140View full textAdd to dashboardCite

“…More recently, BABAR reported evidence for J P = 1/2 − for the Ξ(1690) by analyzing the Legendre Polynomial moments of the Ξ − π + system in the decay Λ + c → Ξ − π + K + [7]. Clear evidence for Ξ(1820) was observed in the K − Λ mass spectrum from a sample of 130±16 events in K − p interactions [8], and the J = 1/2 assumption was ruled out by using the Byers and Fenster technique [9]. Ten years later, a CERN-SPS experiment indicated that Ξ(1820) favors negative parity in the case of J = 3/2 [10].…”

Hyperon Spectroscopy at Hall B, Jefferson Lab

“…Excited cascades can be investigated in reactions such as γp → K + K + Ξ − (1820), Ξ − (1820) → K − Λ, Λ → pπ − . This would allow the determination of the spin and parity of the observed excited cascade states [25]. The polarization of ground state Ξ can also be measured with uncertainties sufficiently small to constrain production models that currently can not separate the contributions of various intermediate hyperon resonances.…”

UCLA Intermediate Energy Nuclear and Particle Physics Research: Final Report

“…The narrowness allows one to determine the spin and parity by a Byers-Fenster [22] or Button-Shafer analysis, rather than a cumbersome partial wave analysis.…”