描述量能器中能量沉積的新函數

Abstract

粒子物理是物理學中一個很重要的領域，物理學家們藉由精準的探測器、穩定的數據汲取系統來進行實驗與收集數據。 藉由實驗數據的分析，物理學家們以探求新物理、理論的驗證以及物理現象的預測。除了有穩定的待測物源、精準敏銳的探測器以及細心的誤差控制以外，物理學家們也必須要有好的數學模型來描述我們獲得的各種實驗能譜，並且藉由合理且適當的擬合來得到準確的物理參數以進行研究。

Crystal Ball函數是Crystal Ball實驗組所開發出來的一個擬合模型，這個模型是用來描述量能器中的沉積能量譜。此函數至今為止已經被使用將近30年並且廣泛的運用在各大實驗中。然而在現代高精準度的實驗要求之下，對於這個函數的精準度要求已經漸漸不足了。在此研究中，我們藉由研究大亞灣實驗的實驗數據以及Geant4的模擬能譜結構來建構一個新的擬合函數。此新函數比起Crystal Ball函數能夠提供更高的精準度以及更多有意義的物理參數。在這份研究中，我們將比較此新模型與Crystal Ball函數的擬合準確度，並且應用此模型研究探測器的非均勻性響應。

The particle physics is one of the important branches of the physics. Physicists rely on the precision detector and stable data acquired system to collect experimental data and perform the experiment. By analyzing the experimental data, physicists explore the new physics, test theories and predict new phenomenon. Except of stable source, sensitive detector and well-controlled t uncertainty, we also need a good mathematical model for describing the data sample during analysis. With appropriate fitting, we can obtain the physical parameter from data for research.

The Crystal Ball function is created by the Crystal Ball Collaboration. This model is used to describe the energy deposit n the calorimeter. It has been used over 30 years and widely applied to many experiments. However, under the high precision requirement, the accuracy of the Crystal Ball function is getting not enough. In this thesis, we study the Daya Bay experiment data sample and Geant4 simulation samples to formulate a new fitting model. The new model has higher accuracy and better performance than the Crystal Ball function. We also use our new function to test the non-uniformity effect in the Daya Bay experiment and compare the result to the Crystal Ball function.