53 research outputs found
Performance studies of a SiPM-readout system with a pico-second timing chip
A pico-second timing (PIST) front-end electronic chip has been developed
using CMOS technology for future electron-positron collider
experiments (namely Higgs factories). Extensive tests have been performed to
evaluate the timing performance of a dedicated SiPM-readout system equipped
with a PIST chip. The results show that the system timing resolution can
achieve for SiPM signals at the minimum-ionizing particles
(MIP) level () and better than for signals
larger than , while the PIST intrinsic timing resolution is
. The PIST dynamic range has been further extended
using the time-over-threshold (ToT) technique, which can cover the SiPM
response spanning from to
Determination of the number of events at BESIII
The numbers of ψ(3686) events accumulated by the BESIII detector for the data taken during 2009 and 2012 are determined to be and , respectively, by counting inclusive hadronic events, where the uncertainties are systematic and the statistical uncertainties are negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of ψ(3686) events for the two data taking periods is
Search for an axion-like particle in radiative J/ψ decays
We search for an axion-like particle (ALP) a through the process ψ(3686)→π+π−J/ψ, J/ψ→γa, a→γγ in a data sample of (2.71±0.01)×109 ψ(3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/ψ→γa and the ALP-photon coupling constant gaγγ are set at 95% confidence level in the mass range of 0.165≤ma≤2.84GeV/c2. The limits on B(J/ψ→γa) range from 8.3×10−8 to 1.8×10−6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165≤ma≤1.468GeV/c2
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