使用CMS檢測器在LHC處使用質子 - 質子碰撞來呈現Z +γ產生橫截面的測量。數據是在2016年收集的，對應於13 TeV的質心能量的35.9 fb ^ -1的積分亮度。選擇具有Z玻色子衰變為一對μ子（μ+μ-）或電子（e + e-）且Z玻色子質量> 50GeV和高橫向動量光子（pT≥20GeV）的事件。基準橫截面僅包括在最終狀態下的額外噴射器的數量中包含地測量。此外，還給出了光子橫向動量pT和三體光子和Z波色子的不變質量的微分截面。通過模擬擬合來自模擬的信號模板和從數據邊帶區域獲得的背景模板，估計主要背景，Z +噴射事件，其中從π0的衰變或從錯誤識別的粒子產生非提示光子。測得的包含基準截面為：σmea= 1776±11（stat）±15（syst）±44（lumi）fb，排他性結果為σmea= 1328±11（stat）±30（syst）±33（lumi） fb。發現這些值與模擬 ”MATRIX“在next-to-next-leading order（NNLO）σNNLO= 1797±41 fb和σNNLO= 1293±48 fb時的預測非常一致。;Measurement of the Z plus γ production cross section is presented using proton-proton collisions at the LHC with the CMS detector. The data were collected in 2016 corresponding to an integrated luminosity of 35.9 fb＾−1 at the center-of-mass energy of 13 TeV. The events having a Z boson decaying to a pair of muons (μ+μ−) or electrons (e+e−) with Mll > 50 GeV and a high transverse momentum photon (pT ≥ 20 GeV) are selected. The fiducial cross sections are measured inclusively, exclusively and in terms of number of additional jets in the final state. Moreover, the differential cross sections in photon transverse momentum pT and three-body invariant mass Mllγ are also presented. The main background, Z+jets events in which a non-prompt photon is produced from the decay of π0 or from mis-identified particles, is estimated by template fitting with a signal template from simulation and background template obtained from the data sideband region. The measured inclusive fiducial cross section is: σmea = 1776 ± 11(stat) ± 15(syst) ± 44(lumi) fb and the exclusive result is σmea = 1328 ± 11(stat) ± 30(syst) ± 33(lumi) fb. The values are found to be in good agreement with prediction from MATRIX at next-to-next-to-leading order (NNLO) σNNLO = 1797 ± 41 fb and σNNLO = 1293 ± 48 fb for inclusive and exclusive, respectively.
