分类: 物理学 >> 核物理学 提交时间: 2016-09-13
摘要: We present physics opportunities and topics with the ss¯ states (strangeonia) that can be studied with the BESIII detector operating at the BEPCII collider. Though the ϕ and η/η′ states have long been established experimentally, only a handful of strangeonia are well known, in contrast to the rich cc¯ charmoium system. An overview of the ss¯states and their experimental status is presented in this paper. The BESIII experiment has collected the world's largest samples of J/ψ, ψ(2S), ψ(3770), and direct e+e− annihilations at energies below the J/ψ and above 3.8\,GeV, and will continue to accumulate high quality, large integrated luminosity in the τ-charm energy region. These data, combined with the excellent performance of the BESIII detector, will offer unprecedent opportunities to explore the ss¯ system. In this paper we describe the experimental techniques to explore strangeonia with the BESIII detector.% at the BEPCII.
分类: 物理学 >> 核物理学 提交时间: 2016-09-06
摘要: We study the photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) of the BESIII detector. The control samples of the initial-state-radiation (ISR) process of e+e−→γμ+μ− at J/ψ and ψ(3770) resonances are used for the calibration of the photon cluster shapes and photon detection efficiency study. The photon detection efficiency is defined as the fraction of predicted photon, determined by performing a kinematic fit with the four momenta of two charged tracks only, matched with the actual photons in the EMC. The spatial resolution of the EMC is studied in polar (θ) and azimuthal (ϕ) angle directions in a cylindrical coordinate system centered at the interaction point, with z-axis along the beam direction.