本論文使用 CMS 偵測器在 LHC Run-II 所收集的數據進行 Z γ 的截面積量測,其總數據量為 138 fb -1 。Z 玻色子是在 LHC 質子-質子碰撞中所產生的,其對撞質心能量為 13 TeV。該分析的訊號事件需要包括從 Z 玻色子衰變成一對電子 (e+e−) 或是ㄧ對緲子(μ+μ−) 以及最終狀態的高能量光子 (final-state photon)。透過擬合候選光子的簇射形狀 (shower shape) 以多元辨識分佈 (multivariateidentification distribution) 的分析方法來提取訊號 (signal)。量測到的 Z γ 的微分截面積隨光子橫向能量 ( E T γ ) 、輕子-輕子-光子橫向動量 ( p T llγ ) 和不變質量 ( m llγ ) 以及噴流 (Jets) 多重性變化之關係也呈現於論文中。論文中也對於量測到的 Z γ 截面積與次領先 順序 (NLO) 的理論預測分佈進行了比較。;The production cross-section of the Z boson in associated with a photon was measured via the charged leptonic channel using data collected during the Run-II operation of the CMS detector, corresponding to an integrated luminosity of 138 fb −1 . The Z bosons were produced in proton-proton collision at the center-of-mass energy of 13 TeV. Signal events were erquierd to include a pair of electrons (e + e − ) or muons (μ + μ − ) decaying from the Z boson and a energetic photon in the final state. Signal yields were extracted by fitting shower-shape multivariate identification distribution of the photon candidates. The differential cross-sections of this process were measured in photon transvere energy (EγT), lepton-lepton-photon transverse momentum and invariant mass (p llγT and mllγ) and the jet multiplicity. The observed cross-sections were compared with the theoretical prediction at Next-to-Leading-Order (NLO).
