Extract Signals by Fitting χ<SUP>2</SUP> Distribution of the Kinematic Fit

PING Rong-Gang; MO Xiao-Hu; DU Shu-Xian; LIU Jing; MA Lian-Liang; SHEN Cheng-Ping; WANG Zhi-Yong; YUAN Chang-Zheng

Chinese Physics C> 2007, Vol. 31> Issue(3) : 229-231

Extract Signals by Fitting χ² Distribution of the Kinematic Fit

Institute of High Energy Physics, CAS, Beijing 100049, China

Abstract
HTML
Reference
Related

PDF

Abstract：
In measuring the ψ(2S) radiative decays at BESⅡ, contribution of the background is serious in most of the final states. To extract the number of signal events, a fit to the χ² distribution of kinematic fit using signal and background components is proposed. Extensive Monte-Carlo simulations (MCS) are performed, and the results show that the shape of χ² distribution of the signal channel looks different from those of the background channels, thus it provides us by fitting the χ² distribution of the data to extract the number of signal events. An input-output test is performed using MCS, and the uncertainty of the fit method is found to be less than 2%.
References

[1] . Particl Data Group. Phys. Lett., 2004, B592: 612. Ablikim M et al(BES Collab.). Nucl. Instrum. Methods,2005, A552: 344

[1]	MO Xiao-Hu . Unbiased χ² Estimator for Linear Function Fit Involving Correlated Data. Chinese Physics C, 2007, 31(8): 745-749.
[2]	LIU Yi-Lei , WANG Guang-Wei , WANG Fang . I/Q Methods Applied to Phase Detection of RF Signals. Chinese Physics C, 2006, 30(8): 780-783.
[3]	GUO Feng-Kun , SHEN Peng-Nian , JIAN Huan-Qing . The ππ Phase Shifts form ψ′→J/ψπ+π－ Decays. Chinese Physics C, 2005, 29(9): 852-855.
[4]	WANG Gui-Mei , WU Wen-Zong , Xiangyang LU , ZHANG Bao-Cheng , QUAN Sheng-Wen , ZHU Feng , LIN LIN , JIAO Fei , ZHAO Kui . Study on HOMs in 1+1/2 Cell Superconducting Cavity. Chinese Physics C, 2005, 29(11): 1077-1080.
[5]	WU Xing-Hua , ZHOU Ming-Zhen , HUANG Tao . Normalization Constants of the Twist-3 Distribution Amplitudes of the Pion and Kaon From the QCD Sum Rules. Chinese Physics C, 2005, 29(8): 727-730.
[6]	ZHANG Yong-Jun , ZOU Bing-Song . Is f₀ Distinguishable from f₂ by One-dimensional Projections of Angular Distributions in J/ψ→f_{J_→ππKK?}. Chinese Physics C, 2004, 28(5): 479-486.
[7]	HONG Xin-Guo , WENG Yu-Xiang , LI Ming . Low Resolution Structure of Integral Membrane Protein Light-harvesting Complex LH2 From Photosynthetic Bacteria in the Detergent Solution by Synchrotron Small-angle X-ray Scattering. Chinese Physics C, 2003, 27(S1): 57-62.
[8]	MO Xiao-Hu , ZHU Yong-Sheng . Correlated Data Fitting and Error Analysis in ψ(2S) Scan Experiment. Chinese Physics C, 2003, 27(6): 474-478.
[9]	XU Tong , SHAO Ming , LI Cheng , CHEN Hong-Fang , XU Zi-Zong . Comparison of the Methods Used in the Scintillator γ Spectrum Fitting. Chinese Physics C, 2001, 25(4): 343-347.
[10]	Yao Xiaoxia , He Zhenmin , Duan Chungui , Li Guanglie , Peng Hongan . Improved Q²-Rescaling Model and the Nuclear Effect of Parton Distribution Functions. Chinese Physics C, 1997, 21(6): 548-553.
[11]	Yang Changgen , Chen Hesheng , Jin Bingnian , Tang Xiaowei . Fitting Method and Error Study for Tau Lifetime Measurements of L3 Experiment. Chinese Physics C, 1994, 18(9): 794-799.
[12]	Wu Mei , Zhang Chunsheng , Li Tipei , Cheng Lingxiang . Probability Distribution of the Pearsou X² of Small Samples. Chinese Physics C, 1994, 18(10): 879-883.
[13]	LIU Jin-Ming , GONG Di . Variational Study of 3-Dimensional SU(2) Lattice Gauge Theory with Independent Plaquette Trial Action. Chinese Physics C, 1993, 17(2): 128-133.
[14]	CHENG Qing-Hua , ZHUANG Peng-Fei , LIU Lian-Shou . Final State Distribution and Signal of Quark-Gluon Plasma in High Energy Heavy-Ion Collisions. Chinese Physics C, 1992, 16(5): 439-445.
[15]	DENG Wei-Zhen , YANG Ze-Sen . Intrinsic Condensate Method for Microsopic IBM2 and Calculation of ¹⁶⁸Er Spectrum. Chinese Physics C, 1992, 16(3): 272-277.
[16]	BIAN Jian-Guo . A REAL-SPACE RENORMALIZATION-GROUP ANALYSIS FOR Z₂ LATTICE GAUGE THEORY COUPLED TO A HIGGS FIELD. Chinese Physics C, 1989, 13(1): 29-34.
[17]	ZHENG Wei-Hong , GUO Shuo-Hong . THE VARIATIONAL CALCULATION OF MASS GAP IN 2+1 DIMENSIONAL U(1) LGT. Chinese Physics C, 1989, 13(2): 184-187.
[18]	ZHENG Wei-Hong , GUO Shuo-Hong . THE VARIATIONAL CALCULATION OF MASS GAP IN 2+1 DIMENSIONAL SU(2) LGT. Chinese Physics C, 1989, 13(1): 83-86.
[19]	LI Wen-Zhu , ZHANG Jian-Bo . VARIATIONAL ANALYSIS OF CUMULANT EXPANSION IN SU(2) LATTICE GAUGE THEORY WITH AN ACTION INCLUDING SIX-LINK LOOPS. Chinese Physics C, 1988, 12(5): 608-615.
[20]	CHEN Tian-Lun , SUO Cun-Chuan . VARIATIONAL ANALYSIS OF PHASE STRUCTURE OF THE SU(2) LATTICE GAUGE THEORY WITH AN ACTION INCLUDING SIX-LINK LOOPS. Chinese Physics C, 1986, 10(2): 158-163.

Access

Get Citation

PING Rong-Gang, MO Xiao-Hu, DU Shu-Xian, LIU Jing, MA Lian-Liang, SHEN Cheng-Ping, WANG Zhi-Yong and YUAN Chang-Zheng. Extract Signals by Fitting χ² Distribution of the Kinematic Fit[J]. Chinese Physics C, 2007, 31(3): 229-231.

RIS(for EndNote,Reference Manager,ProCite)

BibTex

Txt

Milestone

Received: 2006-07-10
Revised: 2006-08-17

Article Metric

Article Views(3203)
PDF Downloads(836)
Cited by(0)

Policy on re-use

To reuse of subscription content published by CPC, the users need to request permission from CPC, unless the content was published under an Open Access license which automatically permits that type of reuse.

通讯作者: 陈斌, bchen63@163.com

1.
沈阳化工大学材料科学与工程学院沈阳 110142

Extract Signals by Fitting χ² Distribution of the Kinematic Fit

Corresponding author: PING Rong-Gang,

Institute of High Energy Physics, CAS, Beijing 100049, China

Received Date: 2006-07-10
Accepted Date: 2006-08-17
Available Online: 2007-03-05

Abstract: In measuring the ψ(2S) radiative decays at BESⅡ, contribution of the background is serious in most of the final states. To extract the number of signal events, a fit to the χ² distribution of kinematic fit using signal and background components is proposed. Extensive Monte-Carlo simulations (MCS) are performed, and the results show that the shape of χ² distribution of the signal channel looks different from those of the background channels, thus it provides us by fitting the χ² distribution of the data to extract the number of signal events. An input-output test is performed using MCS, and the uncertainty of the fit method is found to be less than 2%.