[en] Morphological characteristics of high energy γ-rays are studied using mountain emulsion chambers installed on Mt. Kambala, 5,500m above sea level, atmospheric depth 520 gm cm^-2. The vertical flux, integral energy spectrum, Zenith angle distribution and attenuation length in atmosphere are obtained

[en] The results of the measurement of energy spectra of atmospheric cosmic rays in the energy around 10 TeV measured with emulsion chambers at Mt. Kanbala (5500m above sea-level, atmospheric depth 520 g/cm²) are reported. The power indices of the integral spectra take the values of 2.00±0.08 for gamma-rays and 1.90±0.10 for hadrons, in the energy range from 5 TeV to 20 TeV. Their intensities are compatible with those expected from the primary cismic rays containing fewer protons than in the lower energy region

[en] A new method of emulsion chamber analysis by using an image scanner is developed in order to process a large number of X-ray films used in the Tibet hybrid experiment which is carried out to observe primary proton spectrum in the PeV region. The experimental procedure in this method consists of multiple steps of processing the image of the X-ray films, i.e. the detection of cascade showers induced by high-energy γ-rays, the noise reduction, the spatial reconstruction of γ-families and their energy determination. The quality of the results obtained by the new method is compared with that obtained by the current manual method or Monte Carlo simulations. It is shown that sufficiently high quality of the emulsion chamber analysis is realized by the automatic method both in energy and geometrical resolution

[en] The ATLAS experiment at CERN is scheduled to replace the innermost station of its Muon Spectrometer in the forward region during its Phase-I upgrade in order to enhance the capabilities on triggering and tracking of high transverse momentum muons towards high luminosity LHC runs. The New Small Wheel (NSW), a completely new detector system to be built, is composed of two novel gaseous detectors: Micro-mesh Gaseous Structure (Micromegas) and the small-strip Thin Gap Chamber (sTGC). The sTGC sub-system is the primary trigger detector. It will be equipped with radiation-tolerant, low-latency electronics for reading out over 400,000 channels to identify the bunch crossing time of proton-proton collisions spaced by 25 ns, as well as to collect fine strip charge information for the charged track reconstruction. In this paper, we present the design and development of a set of Front-End Boards (FEBs) for the sTGC detector system. The major challenges in the design will be discussed. These include the accommodation of a few hundred readout channels per single board in a very constrained space, a tight requirement for the Electrostatic Discharge (ESD) protection of 130 nm ASICs, and customized analog input circuits to handle the high rate and high charge signals from the sTGC detectors. Moreover, the FEBs have to incorporate a few hundred parallel inter-chip links at 320 Mbps and several low-latency serial links operating at 4.8 Gbps for the Level-1 and trigger data readout. The characterization of the FEBs performance, both off-detector and on-detector, will be shown.

[en] An RPC carpet covering ∼ 10⁴ m² (ARGO-YBJ experiment) will be installed in the YangBaJing Laboratory (Tibet, P.R. China) at an altitude of 4300 m a.s.l.. A test-module of ∼ 50 m² has been put in operation in this laboratory and about 10⁶ air shower events have been collected. The carpet capability of reconstructing the shower features is presented

[en] Bakelite RPCs, assembled according to the ARGO design, have been operated in the high altitude Laboratory of YBJ using dedicated electronics to pick-up the streamer signal. Here we report on the results concerning absorbed current, single counting rate, efficiency and time resolution. Environmental data concerning the operating temperature inside the ARGO experimental hall are also reported

[en] A 50 m² RPC carpet was operated at the YanBaJin Cosmic Ray Laboratory (Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive Air Showers was studied. Efficiency and time-resolution measurements at the pressure and temperature conditions typical of high mountain laboratories, are reported

[en] We present the ARGO-YBJ experiment, a full coverage detector placed at high altitude (∼ 4300 m a.s.l.) that exploits the RPC technique. Results of a test experiment performed at Yanbajing site, with a full coverage RPC carpet of 50 m² are also presented

[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