Status Report of the DPHEP Study Group: Towards a Global Effort for Sustainable Data Preservation in High Energy Physics

Data from high-energy physics (HEP) experiments are collected with significant financial and human effort and are mostly unique. An inter-experimental study group on HEP data preservation and long-term analysis was convened as a panel of the International Committee for Future Accelerators (ICFA). The group was formed by large collider-based experiments and investigated the technical and organisational aspects of HEP data preservation. An intermediate report was released in November 2009 addressing the general issues of data preservation in HEP. This paper includes and extends the intermediate report. It provides an analysis of the research case for data preservation and a detailed description of the various projects at experiment, laboratory and international levels. In addition, the paper provides a concrete proposal for an international organisation in charge of the data management and policies in high-energy physics

Experimental estimates of higher order pertubative corrections to R\

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 13125 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Improvement of a CP-violation or B"o_s oscillation measurement through the optimal use of discriminating variables

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 13034 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Performance Evaluation of the HAPD in the Belle II Aerogel RICH Counter

International audienceThe Hybrid Avalanche Photo Detector (HAPD) is used as a photon detector for Aerogel Ring Imaging Cherenkov counter (ARICH), a particle identification device at Belle II. ARICH measures Cherenkov angles of photons emitted in silica aerogel radiators, hence a high photon detection efficiency is required by the HAPD module, a combination of HAPD and front-end electronics board. We evaluate the performance of the HAPD modules by measuring the noise level, the offset value, the pulse height, temperature dependency and the variation of performance in the beam commissioning period. This article describes the results of performance evaluation of the HAPD and shows that it fulfills the requirements of ARICH

Performance and commissioning of HAPDs in the Aerogel RICH counter

International audienceThe Belle II Aerogel Ring Imaging Cherenkov (ARICH) counter uses the angular distribution of Cherenkov photons emitted in silica aerogel to discriminate between charged pions and kaons. The Hybrid Avalanche Photo Detector (HAPD) is used as the photo-sensor, and is clearly the most critical component of the detector. HAPDs were installed into ARICH in July 2017, and ARICH was installed in the Belle II spectrometer in the end of 2017. During the Belle II beam commissioning in spring 2018, the performance of HAPDs was evaluated through measurements of the offset value, noise level and pulse height. Long term stability of the signal-to-noise ratio and the fraction of dead channel was also monitored. The signal-to-noise ratio exceeded 6, and the fraction of dead channels was less than 1%. The results of the performance evaluation and of the commissioning showed that the ARICH counter fulfills the requirements

Performance Estimation of the Belle II Aerogel RICH Counter in the First Beam Collision

International audienceThe Belle II experiment at the SuperKEKB facility started the beam collision in 2018, aiming search for the New Physics beyond the Standard Model. The Aerogel Ring Imaging Cherenkov (ARICH) counter is a particle identification (PID) device in the forward endcap of the Belle II detector to provide 4$\sigma$ separation of charged kaons and pions of momenta up to 3.5 GeV. The ARICH counter is a proximity-focusing RICH counter to identify particle species based on the angular distribution of Cherenkov photons located in 30 cm depth of narrow space and 1.5 T of high magnetic field. Two layers of the silica aerogel with different refractive indices emits photons as Cherenkov ring image. A total of 420 of Hybrid Avalanche Photo Detectors (HAPDs) are used to measure the 2-dimensional distribution of photons. We have collected ring images in the first beam collision data during the Phase II commissioning run and studies for the PID performance estimation are being carried out toward the Phase III physics data taking starting in 2019