利用CMS探測器量測7TeV下的Zγ產生截面

Measurement of Zγ production in pp collision at √s = 7 TeV with the CMS detector at the LHC

劉宗凱(Zong-Kai Liu)

指導教授 ： 郭家銘 ； 張元翰

國立中央大學/理學院/物理學系/博士(2011年)

摘要

Zγ生產的量測能提供測試電弱理論結構的機會，也能給予新物理是否存在的線索。此篇論文利用CMS蒐集的 36 pb-1 的質子質子對撞數據，呈現了第一次在總碰撞能量7 TeV下的Zγ產生截面的量測，並選擇Z衰變為電子當作訊號事件。此產生截面量測是針對光子橫向能量大於10GeV，光子與電子空間上的分離ΔR(l, γ) 大於0.7，且輕子對恆定質量大於50GeV。量測的Zγ產生截面為9.5 ± 1.4（統計誤差）± 0.7（統計誤差）± 0.4（光度誤差）pb，與標準模型預測的Zγ產生截面9.6 ± 0.4 pb相符合。

關鍵字

高能實驗

並列摘要

The measurement of Zγ production can provide an opportunity for examining the gauge sector of the Standard Model, and evidences for the existence of new physics. This thesis presents the first cross-section measurement of Zγ → e+e-γ at √s = 7 TeV using 36 pb-1 of proton-proton collision data collected by CMS. The cross-section is measured for the photon transverse energy ETγ > 10 GeV, spatial separation from charged leptons ΔR(l, γ) > 0.7 and dilepton invariant mass Mll > 50 GeV. The σ(pp → Zγ + X) × B(Z → e+e-) is measured to be 9.5 ± 1.4 (stat.) ± 0.7 (syst.) ± 0.4 (lumi.) pb, in agreement with Standard Model prediction of 9.6 ± 0.4 pb.

並列關鍵字

CMS ； di-boson

參考文獻

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