1.创建CMSSW，复制文件和代码到本地
source /cvmfs/cms.cern.ch/cmsset_default.sh
cmsrel CMSSW_8_1_0
cd CMSSW_8_1_0/src
cmsenv
cp -r /data/pubfs/pku_visitor/yutaozhe/public/CMS_winter_school_yutaozhe/*  ./


2.运行Event selection代码产生事例重建的文件

vim EventSelection_dineutrino_Resolved_2018.cpp  打开文件
修改代码第96行 NewFileprov = "/data/pubfs/pku_visitor/yutaozhe/Preselection/"里的路径，修改到自己目录下
运行代码 root -b -q EventSelection_dineutrino_Resolved_2018.cpp 会产生文件：
ST_t-channel_antitop.root  ST_t-channel_top.root  ST_tW_antitop.root  ST_tW_top.root
记住这些产生文件的路径

3.产生data/MC的比较图

vim  plotterPreselection_dineutrino_2018.h
把163-166行的代码：
TFile *file37 = TFile::Open("/data/pubfs/pku_visitor/yutaozhe/Preselection/ST_t-channel_antitop.root");
TFile *file38 = TFile::Open("/data/pubfs/pku_visitor/yutaozhe/Preselection/ST_t-channel_top.root");
TFile *file39 = TFile::Open("/data/pubfs/pku_visitor/yutaozhe/Preselection/ST_tW_antitop.root");
TFile *file40 = TFile::Open("/data/pubfs/pku_visitor/yutaozhe/Preselection/ST_tW_top.root");
中的路径改成上一步中产生文件的路径

root -b -q plotterPreselection_dineutrino_2018.cpp  产生图片，
使用以下命令打开图片
evince TopMass.pdf
evince TopPt.pdf
注意观察图中top的MC分布