以蒙地卡羅法研析大強子對撞機的MBUE事例

Abstract

藉由CDF實驗的數據,使得我們可以在LHC真正運作之前,來以蒙地卡羅法研析模擬的數據,由此來用現行的各種理論模型推測LHC開始運作後,其數據所可能有的各種行為分佈等等. 由此我們特別研析LHC中的MBUE事例,來了解低能量的資料數據分佈,藉此來推測當對撞能量提升到LHC實驗所擁有的14TeV數據行為,並依此來調整在模擬時所使用的各種理論模型還有模擬數據的產生器.

The Tevatron experiments provide us very good information for the QCD modelings of event generators. However, in the LHC era, the collisions is in di fferent region of phase-space from that of Tevatron. A Naive rescaling of cross-sections will not work. The current modeling of non-trivial interplay of perturbative (multiple parton interactions) and non-perturbative (beam remnants, ISR, FSR) aspects based on Tevatron data have large di fferences when extrapolated to the LHC energy. The charged particle and transverse momentum densities relative to the leading jet in di erent regions are examined. The simulation is done with the CMS detector under the start-up LHC conditions where the pile-up e ect can be neglected. This study is devoted to discriminating among di erent models and to help us to understand the QCD Monte Carlo models. Information obtained from this study will be useful to improve/tune Monte Carlo models which were only validated with the low energy Tevatron data.