Purpose The end cap time of flight at Beijing Spectrometer is upgraded with multi-gap resistive plate chamber technology in order to improve the charged particle identification capability. The time-over-threshold is used for the time slewing correction instead of the signal amplitude. Methods The correlation of the multi-peak time-over-threshold and the hit position along the strip of the charged particle is investigated. Implementation of the off-line data calibration method is discussed in detail. Results and conclusion The overall time resolution for pions with momentum around 0.8 GeV/c is about 65 ps.

respectively. In addition, the M 2 γγ-dependent partial widths of the inclusive decay are also presented.

Recent experimental results from Beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from J/\ decays, and a number of new states are found or confirmed, including V, N, X(1835), ZM threshold enhancement in J/\oJZM , a broad resonance in J/\oK K S 0 , decay studies of \ (2S) and F CJ , as well as the results of \ (3770) nondecays. The current status of BEPCII/BESIII, the major upgrade of BEPC/BESII, is also reported. Beijing Spectroscopy, hadron spectroscopy, charm physics, BEPCII The results in this paper are based on the data collected at Beijing Electron-Positron Collider. Beijing Spectroscopy (BES) was upgraded to BESII in 1997, and had been taking data till the end of April in 2004, with a data sample including 58 M J/\ events, 14 M \ (2S) events and data around \ (3770) with a luminosity of about 27 pb 1 . Many results have been obtained from those data, and about 80 papers have been published on the famous international journals, such as Phys Rev Lett, Phys Lett B and Phys Rev D, in which more than 10 papers were published on Phys Rev Lett. This article is divided into several sub-sessions about the results from J/\, \ (2S) and \(3770),There has been evidence for a low mass pole in the early DM2 [1] and BESI [2] data on J/\ to ZS S . A huge event concentration in the I = 0 S-wave S S channel was seen in the region of m S S around 500 600 MeV in a pp central production experiment [3] . This peak is too large to be explained as a background [4] . There have been many studies on the possible resonance structure in SS elastic scattering [5] . It was later proved that the V(sigma) resonance is unavoidable in the chiral perturbation theory in order to explain the S S scattering phase shift data [6] . E791 experiment