Observables in high-statistics measurements of the reactionp¯p→Λ¯Λ

Abstract

Associated strangeness production was studied in the pp ! ! p + p reaction at the CERN antiproton facility LEAR using the experimental setup of PS185. Results from two high{statistics measurements at incident a n tiproton momenta of 1:642 and 1.918 GeV/c are reported. Approximately 40 000 reconstructed events at each momentum have allowed us to measure the total and dierential cross-sections, the spin polarizations, the spin correlations, and the singlet fractions of the pair. Since the decays of both the and the w ere simultaneously observed in the same detector, we are able to provide upper limits on CP and CPT violation phenomena in the weak interaction.

Spin observables in with a transverse initial state polarization

“…Thus a preliminary study of this observable can be used to warn of potential difficulties in performing a global fit to the full parameter set. It should be noted that C nn00 has been previously measured forpp →ΛΛ near threshold and that it tends toward the value +1 for only a narrow range of production angle θ [2]. This indicates that, with the possible exception of that narrow angular range, determination of the transition matrix parameters should, in principle, be possible with data of the type collected by PS185/3.…”

“…Thus, the transverse target polarization allows access to the complete set of spin observables, not just the subset upon which the literature has previously focused. This discussion is especially relevant in light of the data collected by PS185/3 at LEAR.Exclusive production of antihyperon-hyperon states from antiproton-proton annihilation (pp → Y Y ) has been extensively studied near threshold by the PS185 collaboration throughout the 13 year lifetime of LEAR at CERN [1,2]. Results for the total and differential cross-sections and those spin observables depending only on final state spins have been published for a range of energies and channels.…”

“…Exclusive production of antihyperon-hyperon states from antiproton-proton annihilation (pp → Y Y ) has been extensively studied near threshold by the PS185 collaboration throughout the 13 year lifetime of LEAR at CERN [1,2]. Results for the total and differential cross-sections and those spin observables depending only on final state spins have been published for a range of energies and channels.…”

Experimental determination of the complete spin structure forp¯p→Λ¯ΛatFields1, Paschke2, Quinn3 et al. 2006Phys. Rev. CSelf Cite230100View full textAdd to dashboardCite

“…This experiment, carried out by the PS185 collaboration, expands upon a series ofȲ Y production and related experiments [1,2,3,4] which have previously been performed by this collaboration using the same detector system. These covered wide-ranging kinematics from very near threshold to higher energies at which the larger cross section allowed high-statistics studies to be made.…”

Examining Cp Symmetry in Strange Baryon Decays

“…To date all searches of CP nonconservation in strange-baryon sector focussed on the Λ → pπ decay, with Λ's and Λ's produced in pp collisions 2,3 or from the J/Ψ decays. 4 The best result of 0.013 ± 0.022 for AΛ came from LEAR PS185.…”