[en] A new experiment to observe gamma rays around 100 TeV at Yanbajing (4300 m) in Tibet, China is planned by a collaboration between China and Japan. To study the feasibility of this experiment a test array was built at Mt. Norikura in Japan. Preliminary results from a search for gamma rays from Cyg X-3 and Her X-1 observed by this air shower array showed the upper limit fluxes of 5.6 x 10^-13 cm^-2s^-1 and 3.0 x 10^-13 cm^-2s^-1 with a 95% confidence level above 150 TeV, respectively. At the first step experiment we will set up 65 scintillation counters in Tibet. An angular resolution of the apparatus will be better than 1deg at an energy of 100 TeV. The detectors are monitored by a nitrogen laser system automatically which guarantees a long term quality of the data. (orig.)

[en] We present the x_F and p_T differential cross sections of J/ψ and ψ^', respectively, in the ranges -0.05< x_F<0.25 and p_T<3.5 GeV/c. The data samples are constituted by about 12000 J/ψ and 200 ψ^' produced in proton-silicon interactions at 800 GeV/c and decaying into opposite sign muons. The x_F and p_T distributions are compared with recent results from experiments E789 at the same energy and to leading order QCD predictions using the MRS D0 parametrization for the parton structure function. The measured shapes of the differential cross sections, except for the dσ/dx_F at small x_F, agree very well with the prediction, even though their value is quite a bit larger than the prediction. We also present the cosθ differential cross section of the J/ψ which indicates unpolarized production in contrast with color octet models predictions. copyright 1997 The American Physical Society

[en] The cross section for b bar b production in 800 GeV/c pN interactions has been measured in Fermilab experiment E771 to be 43⁺²⁷_-17(stat)⁺⁷_-7(syst) nb per nucleon from the observation of events in which both the b and the bar b decay semimuonically or a B decays into a J/ψ followed by J/ψ→μ⁺μ^- . copyright 1998 The American Physical Society