Study On The Space-time Structure Of Higgs Jet In E~+e~- Collision

The standard model of particle physics is one of the most classical theoretical models which has been tested by experiments for decades and successfully predicts many fundamental particles.Higgs boson is one of the most important fundamental particles in the standard model.The study of its properties is of great significance to perfect the Standard Model and explore new physics.Scientists believe that the Circular Electron-Positron Collider is one of the most ideal Higgs factories,a powerful tool for studying the properties of Higgs particles and finding new physics.It is phenomenology study using Monte Carlo generator that plays an important role in better understanding the experiment result and extending the application of physics theory.In this paper,the basic physics knowledge related to Higgs characteristics in electron-positron collisions are introduced which include the standard model theory,the Brout-Englert-Higgs mechanism,the Pythia model,the Hanbury-Brown-Twiss(HBT)correlation and the Higgs physics at the CEPC(Circular Electron Positron Collider).Finally,we introduce the study of Higgs characteristics in electron-positron collisions by using with Pythia model at 250GeV.The space-time structure of the Higgs boson in different decaying channels is studied with the HBT correlation method using e~+e~-collision events produced by the Monte Carlo generator Pythia8.219 at?s=250GeV.In this paper,the study of Higgs boson is mainly divided into two steps:(1)To test the validity of Pythia model by studying the invariant mass of Dijet in electron-positron colliding events along with Higgs boson;(2)To investigate the space-time structure of Higgs jet by using the HBT correlation method,then we calculate the decay radii and decay lifetime according to fitting the correlation function of two identical pions(?~+,?,?)from Higgs jets of different decay channels.Finally,the measurements of the Higgs boson radius and decay lifetime are derived from the HBT correlation of the final state pions,with an upper bound of<1.15±0.07 fm and?<(1.30±0.14)×10 fs.This result is consistent with CMS data.