在Belle作質子鑑別的研析

Abstract

我們使用Λ樣本，來研究Belle實驗室中系統有能力鑑別出來的質子百分比，和與此相關的系統誤差，在論文中使用的Λ樣本數量是由π粒子和p粒子重組並選取適合的質量範圍而來，我們比較在各種不同的質子動量下，取不同的粒子鑑別限制（PID）時，Data和MC之間Λ樣本降低的百分比有何不同，來自Ks和γ的背景已經使用一些動量限制來適當的排除，在這份論文中，我們使用實驗7到實驗49中的on-resonance數據來源，在此數據中所累積的粒子數目（luminosity）492fb-1，研究結果顯示在Belle實驗中對於質子的鑑別是穩定的，其系統誤差大概在2%以內。

Inclusive Lambda sample are used to determine the Proton Identification efficiency and related systematic uncertainty for the Belle experiment. The number of tagged Lambda's can be estimated from the reconstructed mass spectrum of proton and pi- from Lambda decays. We compare momentum-dependent efficiency between Data and MC with various proton identification criteria. Background events from Ks and gamma's are rejected properly using kinematical information. In the study, we used on-resonance data from EXP7 to EXP49, corresponding to an integrated luminosity of 492 fb-1. The results indicate that the performance of proton identification at Belle is quite stable and the associated systematic uncertainty is within 2%.