分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: Many extensions of the Standard Model introduce a new type of weak-interacting degrees of freedom. These models are motivated by the results of recent experimental anomalies. Typical models, such as Next-to-Minimal Supersymmetric Standard Model and Light Hidden Dark-sector Model, introduce the possibilities of low-mass Higgs and dark bosons. The masses of such particles are expected to be few GeV and thus making them accessible at BESIII experiment, an e+e− collider experiment running at tau-charm region. This report summarizes the recent results of low-mass Higgs and dark bosons searches at BESIII.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.
分类: 物理学 >> 核物理学 提交时间: 2016-09-13
摘要: We study the photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) of the BESIII experiment. The control sample of the initial-state-radiation (ISR) process of e+e−→γμ+μ− is used at J/ψ and ψ(3770) resonances for the EMC calibration and photon detection efficiency study. Photon detection efficiency is defined as the predicted photon, obtained by performing a kinematic fit with two muon tracks, matched with real photons in the EMC. The spatial resolution of the EMC is defined as the separation in polar (θ) and azimuthal (ϕ) angles between charged track and associated cluster centroid on the front face of the EMC crystals.
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.