[en] We have observed antipp annihilation at rest into Ksub(S)Ksub(S) using a hydrogen gas target at normal temperature and pressure. This channel is forbidden from atomic antipp S states. A preliminary analysis gives a branching ratio of (2.2+-0.5+-0.5) x 10^-5. We have also observed the channel Ksub(S)X where X is a Ksub(S) or Ksub(L) escaping detection in our apparatus. The Ksub(S)Ksub(L) mode is allowed from atomic S but forbidden from atomic P orbitals. Using the known branching ratio of (7.8+-0.4) x 10^-4 for antipp→Ksub(S)Ksub(L) and our preliminary figure of (3.8+-0.4+-0.8) x 10^-4 for Ksub(S)X we deduce that the fraction of S state annihilation in hydrogen gas at NTP is (46+-10)%. This in turn yields an absolute branching ratio of (4.1+-0.9+-1.0) x 10^-5 for antipp→Ksub(S)Ksub(S) from P orbitals, showing that the (Ksub(S)Ksub(S)+Ksub(L)Ksub(L) mode is suppressed by an order of magnitude compared to the Ksub(S)Ksub(L) mode. 6 refs

[en] We have searched for monochromatic pion emission and for radiative transitions in anti-pp annihilation at rest from atomic P states. No new states are observed. The status of analysis of the ππ KK final state is discussed. 7 refs

[en] X-rays from the K and L series of p-bar-p atoms formed in hydrogen gas at NTP have been observed in association with annihilations into neutral particles. (author)

[en] Cross sections are presented for the inclusive photoproduction of K/sub S/⁰, Λ, Lambda-bar, Ψ^-, Xi-bar ^-, Σ⁰, and Σ/sup asteriskplus-or-minus/(1385) at 20 GeV. An upper limit to Ω^- production is also given. The data come from 284 000 hadronic events photoproduced in the SLAC 1-m hydrogen-bubble-chamber hybrid facility exposed to a nearly monochromatic, polarized 20-GeV backscattered photon beam. A comparison of the K/sub S/⁰, Λ, Lambda-bar, and Ψ^- rates per inelastic event to π^+-p data show that γp rates are consistent with being higher than the π^+-p rates, providing evidence of an ss-bar component of the photon. The pair cross sections for K/sub S/⁰K/sub S/⁰, K/sub S/⁰Λ, K/sub S//sup o/Lambda-bar, and ΛLambda-bar are presented. The x/sub F/ distributions of the Λ, Lambda-bar, and Ψ^- are compared to a quark-diquark fusion model, giving information on strange-baryon photoproduction mechanisms

[en] AN analysis is presented of two body final states of collinear charged pions or kaons from antiproton-proton annihilation at rest in the ASTERIX spectrometer at LEAR. The relative branching ratio of kaons to pions, which is sensitive to the dynamics of quark-antiquark annihilation and rearrangement, is shown to differ for P and S wave initial states

No abstract available

[en] We propose to study in the ACOL era the strong interaction physics accessi - ble with antip (and eventually antin) annihilations at LEAR energies with a lar - ge acceptance detector capable of identifying and measuring accurately the charged kaons and pions and the gammas present in the annihilation final state. This detector would be much more powerful than the equipment presently used at LEAR to study exclusively annihilation channels. Highlights of the physics pro - gram would be: a) search and study of spectroscopy and decays of non exotic an - tiqq and exotic mesons (glueballs, hybrids, multiquarks systems) with an antip (antin) external beam and, at higher energies, using LEAR in the pantip collider mode. b) Study of the dynamics of antiN annihilations with protons and nuclei. We have given priority in the detector design to redundant charged kaon identi - fication and good charged particles momentum measurements both at low and high momenta and to the possibility of changing or selecting different initial states (S and P wave pantip annihilation at rest, antipn annihilation in antipd inter - actions with measured recoil proton etc.). The detector is based mostly on avai - lable equipment formerly used in high energy physics experiments and on established detection techniques. It includes a spiral projection chamber sur - rounding a gas target with ultrathin window (at the extracted beam) or the beam pipe (in the antipp collider operation), the magnet and the 42 layers drift chambers of the Axial Field Spectrometer, barrels of time of flight scintillators, peripheral γ detectors made with converters and CHARM 1 propor - tional drift tubes and limited streamer tubes and two compact end-cap gamma calorimeters. 11 refs

No abstract available

[en] First results in p-barp annihilation in hydrogen gas from atomic p states are presented. Annihilation into rhoπ occurs mainly from the isospin I = 0 state of the p-barp system. The rate for p-barp → K⁺K^- relative to p-barp → π⁺π^- is 0.15 +- 0.03. No narrow state associated with monoenergetic pion emission is seen. The 5σ upper limit is 2 x 10^-3. (author)

[en] Seventy-one events containing charmed particle decays have been observed in an experiment using the SLAC Hybrid Facility exposed to a backward scattered photon beam. Results for the charmed meson lifetimes are consistent with the published results from the previous experiment and the two data samples have been combined yielding a total sample of 136 charm events. The charmed meson lifetimes are measured to be tausub(D)+-=(8.6+-1.3sub(-0.3)sup(+0.7)) x 10^-13sec, tausub(D)0=(6.1+-0.9+-0.3)x10^-13sec. The total charm cross section at a photon energy of 20 GeV has been measured to be (62+-8sub(-10)sup(+15))nb. There is evidence for both DDX and DΔ⁺sub(c)X production with σsub(DΔ⁺sub(c))/σsub(charm) = (71 +- 11 +- 6)%. (author)