Sangsik Yoon ; Doris Kim

2019
Soongsil University Seoul

Abstract: The problem of the simulated lifetime of secondary Lambda_0 particles in the Belle II detector simulation has been reported by Hikari Hirata at Nagoya University. As stated in her report, the difference between the simulated lifetime of secondary Lambda_0 particles and the one of primary Lambda_0 particles is about 10 percent. In the Belle II experiment simulation, the particles produced by event generators, such as the continuum generator or the ParticleGun, are taken as the input information for the Geant4 simulation; they are called the primary particles. Depending on the physics processes of the Geant4, primary particles produce their daughter particles; they are called the secondary particles. In this undergraduate thesis, the issue is reproduced using the MC11 ccbar continuum sample, and the length of flight is plotted against the momentum. The result of the plots shows that the discrepancy is dominated in p < 1 GeV. In consequence, the ParticleGun is used to test secondary Lambda_0 particles in the range p < 1 GeV. The results obtained from the ParticleGun show that the simulated lifetime of the secondary Lambda_0 particles tends to decrease as the momentum of their mother particles increases. (The paper format modified for the Belle II document server.)

Note: Presented on 28 05 2019
Note: BSc