Study of K<SUB>s</SUB><SUP>o</SUP> Reconstruction and Lifetime Measurement at BESⅡ

WANG Zhe; YUAN Ye; ZHANG Chang-Chun

Chinese Physics C> 2003, Vol. 27> Issue(1) : 1-6

Study of K_s^o Reconstruction and Lifetime Measurement at BESⅡ

Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039, China

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Abstract：
The beam collision center of the BEPC has slightly shifted from geometrical origin of the BES detector and the beam bunch of the BEPC also has certain size. For these reasons, to measure K_s^o lifetime, primary vertex reconstruction must be carried out. After the investigation of di-muon, bhabha and hadron events, the beam collision center for each run is determined by bhabha and di-muon events. For the large branching ratio of and the existence of the resonance of KⅡ0 , this channel is chosen to provide much pure K_s^o signal. With the aid of M. C. tools at BES Ⅱ , existing software for secondary vertex reconstruction is adjusted and improved. A new method of secondary vertex determination is used and a better position resolution of secondary vertex is obtained. The lifetime of Ks0 is measured with channel and the inclusive K_s^o mass is investigated with BES Ⅱ 's 50M J/ψ data sample, which give consistent Ks0 lifetime and mass with PDG' s value within error. 1C fit on K⁰_s mass is also studied with M. C. events. The resolution of momentum and energy of 7π+ , π- and K, is improved too.

References

[1]

BES Collab. Nucl, Instr. Meth.1994,A344:3192 BES Collab. The Bes Upgrade,Nucl. Instr. Meth. 2001, A458 : 6273 JIANG Zhi-Jin. A Study of Particle Separation with Discriminant Analysis Method and the Use Data Analysis. PhD. Thesis, Institute of High Energy Physics,The Chinese Academy of Science,19934 LIU Zhao-Feng. Study of J/ψ Radiative Decay to KsoKso.Master Thesis ,Wuhan Univeisity,2001 (in Chinese)(刘朝峰.J/ψ辐射衰变到KsoKso的实验研究.硕士论文, 武汉大学, 2001)5 BES-II Analysis Software Lib(V103),Institute of High Energy Physics, HP/UNIX and PC/Linux work station,2000,96 Gluckstern R L. Nucl. Instr. Meth. ,1963,24:3817 Csoma S E et al . Phys . Lett . ,1987 , B191(3): 318-3228 ZHU Yong-Sheng. Probability Statistics in Experimental Phys.Bei-jing:Acedemic Press,1991 .340-344 (in Chinese)(朱永生.实验物理中的概率和统计.北京:科学出版社, 1991.340-344 )

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WANG Zhe, YUAN Ye and ZHANG Chang-Chun. Study of K_s^o Reconstruction and Lifetime Measurement at BESⅡ[J]. Chinese Physics C, 2003, 27(1): 1-6.

WANG Zhe, YUAN Ye and ZHANG Chang-Chun. Study of K_s^o Reconstruction and Lifetime Measurement at BESⅡ[J]. Chinese Physics C, 2003, 27(1): 1-6. shu

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Received: 2002-04-01
Revised: 1900-01-01

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沈阳化工大学材料科学与工程学院沈阳 110142

Study of K_s^o Reconstruction and Lifetime Measurement at BESⅡ

Corresponding author: WANG Zhe,

Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039, China

Received Date: 2002-04-01
Accepted Date: 1900-01-01
Available Online: 2003-01-05

Abstract: The beam collision center of the BEPC has slightly shifted from geometrical origin of the BES detector and the beam bunch of the BEPC also has certain size. For these reasons, to measure K_s^o lifetime, primary vertex reconstruction must be carried out. After the investigation of di-muon, bhabha and hadron events, the beam collision center for each run is determined by bhabha and di-muon events. For the large branching ratio of and the existence of the resonance of KⅡ0 , this channel is chosen to provide much pure K_s^o signal. With the aid of M. C. tools at BES Ⅱ , existing software for secondary vertex reconstruction is adjusted and improved. A new method of secondary vertex determination is used and a better position resolution of secondary vertex is obtained. The lifetime of Ks0 is measured with channel and the inclusive K_s^o mass is investigated with BES Ⅱ 's 50M J/ψ data sample, which give consistent Ks0 lifetime and mass with PDG' s value within error. 1C fit on K⁰_s mass is also studied with M. C. events. The resolution of momentum and energy of 7π+ , π- and K, is improved too.