A quark model of antilambda-lambda production in p̄p interactions

Measurement of Spin-Transfer Observables inp¯p→Λ¯Λat1.637 GBassalleck1, Berdoz2, Bradtke3 et al. 2002Phys. Rev. Lett.15060View full textAdd to dashboardCite

“…Measurements for S F have often been quoted as an av- Predictions from the MEX model [6] (solid) are superimposed. The QG model predicts SF = 0 uniformly [9].…”

“…Given the uncertainty in initial-and final-state interactions, as well as freedom in adjusting coupling strengths, calculations based on each of these two approaches have successfully reproduced the previously measured observables, although these calculations are quite different in predictions of the reaction dynamics [5,6,9]. One prominent disagreement between the models is the role of the tensor interaction.…”

“…For those observables which could also be extracted from previous measurements performed without target polarization, good agreement is found between the published results [2] and the corresponding observables found from this fit of the complete set of parameters of the spin scattering matrix. Figure 1 shows results for the depolarization D nn and polarization transfer K nn , along with predictions from full QG [9] and MEX [6] calculations which include ISI and FSI effects. These results clearly indicate a failure of both models to correctly describe the reaction dynamics in this kinematic region.…”

Spin observables in with a transverse initial state polarization

“…Two types of models with different physical motivations have been successfully used to describe the reaction in this energy regime: K and K * meson exchange [4,5] and effective quark models [6,7]. While careful applications of each of these approaches have been able to describe the existing data with reasonable accuracy, differing predictions are obtained for those observables which depend on initial state spin [4,6]. There has also been growing interest in the relevance of the spin structure ofpp →ΛΛ to the question of the strangeness component of the nucleon [8,9].…”

“…The implications of this application of the formalism must be carefully explored for the larger set of observables available to PS185/3 [14,15]. The recent literature discussing the strangeness production dynamics has focused on the depolarization D nn , and, to a lesser extent, other rank-2 spin observables to which PS185/3 is directly sensitive [3, 4,6,8,14]. As will be shown below, the use of a transverse target polarization, in principle, allows the complete determination of the spin structure of the reaction.…”