R&D on long-strip MRPC
Multi-gap Resistive Plate Chamber (MRPC), which has excellent performance and relatively low cost per channel, is a good candidate for Time-of-Flight (TOF) system in modern high energy physics experiments. A new kind of MRPC, Long-strip MRPC (LMRPC) with 50 cm × 2.5 cm strips, was tested at GSI-FOPI with secondary beam. The resets show that this LMRPC prototype can achieve 60 to 70 ps σ time resolution and greater than 97% detecting efficiency. The cross talk between readout strips is less than 2%. The measured spatial resolution along the strips is about 0.36 cm σ.
The compressed baryonic matter experiment at FAIR
The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The goal of the CBM research program is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions. This includes the study of the equation-of-state of nuclear matter at high densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure both bulk observables with large acceptance and rare diagnostic probes such as charmed particles and vector mesons decaying into lepton pairs.
Maximum freeze-out baryon density in nuclear collisions
Using simple parametrizations of the thermodynamicfreeze-out parameters vextracted from the data over a wide beam-energyrange, we reexpress the hadronic freeze-out line in terms of theunderlying dynamical quantities, the net baryon density rhoB and theenergy density epsilon, which are subject to local conservation laws.This analysis makes it apparent that rhoB exhibits a maximum as thecollision energy is decreased. This maximum freeze-out density hasmu=400-500 MeV, which is above the critical value, and it is reached fora fixed-target bombarding energy of 20-30 A GeV.