Overview

　　ALEPH Collaboration is one of the four large experiments on the electron-positron collider LEP at CERN, which is the highest energy e+e- collider in the world. The other three experiments are L3, DELPHI and OPAL. About 400 physicists and engineers from 30 institutions of l0 countries have participated in this collaboration.

　　According to the written reply of the Chinese Academy of Sciences approved by vice president QIAN Sanqiang in 1982, the Institute of High Energy Physics (IHEP) began to participate in ALEPH Collaboration in 1983 as one of the earliest members of the ALEPH participants. In September 1984, Professor H. Schopper, director general of CERN and Professor Ye Minghan, director of the Institute of High Energy Physics signed "the memorandum of mutual understanding between CERN and members of ALEPH Collaboration" (CERN/EF/1610H/J1).

　　ALEPH detector is located 125 meters deep underground. It includes the following sub- detectors (from inner to outer): silicon micro-strip vertex detector, inner drift chamber, time projection chamber, electromagnetic calorimeter, superconducting solenoid magnet coil, hadron calorimeter and muon detector. With these sub-detectors, one can identify all the final state particles and get all round information of these particles of all events including momentum, energy, track, interactive vertex, etc. of these various final state particles, with which the complicated physics phenomena could be analyzed.

Significance

　　The main purpose of ALEPH experiment is to precisely measure Z particle and research the most advanced topics of physics in this energy region.

　　To participate in this important international collaboration, the important significance for IHEP is the following: firstly, to increase the influence of IHEP on the international community of high energy physics; secondly, to cultivate a team working in the most advanced field of high energy physics and thirdly, to promote the BEPC project. For example, the graphic display software package, Monte Carlo system program as well as magnetic field fit program of BES are developed based on ALEPH software. The production, assembly and test of plastic steamer tubes keep at the worldwide advanced level.

　　Around 1984-1985, CERN and Italian INFN provided IHEP with the devices and tools costing about 8000 US dollars. CERN also rendered freely to IHEP many software packages including HISTORIAN software management system, etc.

　　At ALEPH site and in the poster of ALEPH drawings, the Chinese national flag together with the flags of other ten countries are displayed as one of the members with equality owing to the Chinese material contribution.

ALEPH Home Page 

http://alephwww.cern.ch