Study of the Hardness Property of Quark and Gluon Jets

CHEN Gang; LIU Lian-Shou

Chinese Physics C> 2004, Vol. 28> Issue(5) : 469-474

Study of the Hardness Property of Quark and Gluon Jets

CHEN Gang ,
LIU Lian-Shou ^,

Department of Physics,China University of Geosciences,Wuhan 430074,China2 Institute of Particle Physics,Huazhong Normal University,Wuhan 430079,China

Abstract
HTML
Reference
Related

PDF

Abstract：
The 3-jet events from hadronic Z⁰ decay is studied using Monte-Carlo simulation. Quark and Gluon jets are identified through the b-tag method. A new physical quantity——hardness is defined, and the hardness distributions of quark and gluon jets are calculated. The dependence of the average multiplicity and average transverse momentum on hardness as well as the multiplicity and transverse momentum distributions in a certain hardness range in the quark and gluon jets are calculated respectively, and compared. It is found that the properties of quark and gluon jets are considerably different in these respects. The properties of quark jets are almost independent on hardness, while those of gluon jets have strong correlation with hardness. When H_d>10GeV the average multiplicity and average tranverse momentum of gluon jets are higher than those of quark jets; but when H-d<6GeV the results are reversed. This indicates that the conclusion on gluon jets being “fatter” than quark jets is valid only for hard gluons.

References

[1]

. Brandel ik R et al (TASSO Collab. ) . Phys. Lett. , 1979, B86: 2432. Abreu P et al ( DELPHI Collab. ) . Eur. Phys. J. , 1998, C4: 1 .. 173. Buskulic D et ak ( ALEPH Collab. ) . Phys. Lett . , 1996, B383: 3534. Acton P D et al ( OPAL Collab. ) . Z. Phys. , 1993, C58: 387; 1995,C68: 1795. ZHANG Kun Shi, CHEN Gang, YU Mei Ling et al. HEP NP, 2002,26: 1110 (in Chinese)(张昆实,陈刚,喻梅凌等.高能物理与核物理,2002,26:111)6. CHEN Gang, ZHANG Kun Shi, LIU Lian Shou. SCIENCE IN CHINA,2002, A32: 1088(in Chinese)(陈刚,张昆实,刘连寿.中国科学,2002, A32:1088)7. YU Mei Ling, LIU Lian Shou. A Mont e Carlo Study on the Iden tification of Quark andGluon Jets. In: Proc. of the XXXI International Symposium on Mult ipart icle Dynamics. Datong China. Sept. 2001, eds.BAI Yu Ting, YU Mei Ling, WU Yuan Fang, Singapore: World Scientific; hep- ph/01114248. Derrick M et al (HRS Collab. ) . Phys. Let t. , 1985, B165: 4499. Derrick M et al (HRS Collab. ) . Phys. Rev. Lett. , 1989, 63: 1710. YU Mei Ling, LIU Lian Shou. Chin. Phys. Lett. , 2002, 19: 647 ..65111. Abreu P et al (DELPHI Collab. ) . Phys. Lett. , 1999, B449: 383

[1]	B.Betz¹ , 2 , P.Rau¹ , H.Stocker¹ , 3 . Mach Cones Induced by Di-Jets at RHIC and LHC: The Speed of Sound of Big Bang Matter. Chinese Physics C, 2007, 31(12): 1127-1129.
[2]	WEI Hui-Ling , CHEN Gang . Study on the Characters of Angular Distribution of Quark Jets and Gluon Jets. Chinese Physics C, 2007, 31(10): 907-912.
[3]	ZHANG Kun-Shi , LIU Lian-Shou . On the Identification of Quark and Gluon Jets Using Artificial Neural Network Method. Chinese Physics C, 2004, 28(11): 1141-1145.
[4]	SHAO Feng-Lan , XIE Qu-Bing , LI Shi-Yuan . Sensitive Observables for Color Connections in Three-Jet Events at Z⁰ Pole. Chinese Physics C, 2003, 27(6): 479-483.
[5]	XING Xiu-Wen , ZHONG Wei-Li , LIU Lian-Shou . A Monte Carlo Study of the Fractal Property inside Jets Produced in High Energy e⁺e^－ Collisions. Chinese Physics C, 2003, 27(2): 95-98.
[6]	WAN Jun-Sheng , PAN Xiao-Bing , ZHAO Zhu-Min , CHEN Li-Xin , JING Chun-Yuan , WANG Dao-Hua . Theoretical Studies on the New System of Neutron Flux Measurement in the Nuclear Reactor. Chinese Physics C, 2002, 26(10): 1027-1035.
[7]	SHAO Feng-Lan , XIE Qu-Bing , LI Shi-Yuan . Study of Colour Connections via Two-Jet Like Events in e⁺e^－ Annihilation. Chinese Physics C, 2002, 26(11): 1103-1109.
[8]	YIN Jian-Wu , LIU Feng . On the Dynamical Fluctuations in the Production and Evolusion of Jets in High Energy Hadron-Hadron Collisions. Chinese Physics C, 2002, 26(5): 477-483.
[9]	YU YouWen , ZHANG ZongYe . NN Spin-Orbit Force from the Quark-Antiquark Pair Creation Model. Chinese Physics C, 2000, 24(7): 649-655.
[10]	He Zejun , Zhang Jiaju , Liu Bo , Qiu Xijun . Rapidity Dependence of Dilepton Production in Baryon-Tich Quark-Gluon Matter. Chinese Physics C, 1999, 23(4): 375-379.
[11]	He Zejun . Characteristic Dilepton Distribution for Quark-Gluon Matter. Chinese Physics C, 1997, 21(3): 269-274.
[12]	Liu Ming , Liu Feng(Y) , Liu Feng , Liu Lianshou . On the Methods of Jet Identification in High Energy Collsions. Chinese Physics C, 1997, 21(2): 138-145.
[13]	Hou Defu , Li Jiarong . On the Next to Leading Order Debye Screening Mass in QGP. Chinese Physics C, 1996, 20(6): 533-537.
[14]	Li Yunde , liu lianshou . Two-Jet Production via Resolved Photon Processes at HERA. Chinese Physics C, 1996, 20(7): 601-609.
[15]	FANG Hai-Ping , XIE Qu-Bing , LAI Xiao-Ping . RAPIDITY DISTRIBUTION AND BARYON-ANTIBARYON CORRELATIONS IN e⁺e^－→TWO JET EVENTS. Chinese Physics C, 1989, 13(6): 518-525.
[16]	XIE Qu-Bing , LIU Xi-Ming . QUARK PRODUCTION RULE IN e⁺e^－→TWO JETS EVENTS AT HIGH ENERGY. Chinese Physics C, 1987, 11(6): 834-839.
[17]	LI Wen-Zhu , DONG Shao-Jing . QCD JET IN POLARIZED e⁺e^－ ANNIHILATION. Chinese Physics C, 1984, 8(1): 52-58.
[18]	DING LIN-KAI , ZHU QING-QI , GUO KE-ZHUN . CLUSTER PHENOMENA OBSERVED IN EMULSION CHAMBER EXPERIMENTS IN ENERGY REGION OF 10¹⁵—10¹⁶ eV AND HADRON JETS WITH LARGE TRANSVERSE MOMENTA. Chinese Physics C, 1982, 6(6): 657-664.
[19]	CHANG CHAO-XI . ON STRUCTURE OF MULTIPARTICLES IN QUARK JETS FOR e⁺e^- COLLIDING. Chinese Physics C, 1982, 6(1): 123-128.
[20]	Wu Yong-shi , Peng Chia-kwei . A NOTE ON THE EQUATIONS OF SU(2) INSTANTONS. Chinese Physics C, 1978, 2(1): 87-89.

Access

Get Citation

CHEN Gang and LIU Lian-Shou. Study of the Hardness Property of Quark and Gluon Jets[J]. Chinese Physics C, 2004, 28(5): 469-474.

CHEN Gang and LIU Lian-Shou. Study of the Hardness Property of Quark and Gluon Jets[J]. Chinese Physics C, 2004, 28(5): 469-474. shu

RIS(for EndNote,Reference Manager,ProCite)

BibTex

Txt

Milestone

Received: 2003-06-27
Revised: 1900-01-01

Article Metric

Article Views(4307)
PDF Downloads(491)
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

Study of the Hardness Property of Quark and Gluon Jets

Corresponding author: LIU Lian-Shou,

Department of Physics,China University of Geosciences,Wuhan 430074,China2 Institute of Particle Physics,Huazhong Normal University,Wuhan 430079,China

Received Date: 2003-06-27

Accepted Date: 1900-01-01

Available Online: 2004-05-05

Abstract: The 3-jet events from hadronic Z⁰ decay is studied using Monte-Carlo simulation. Quark and Gluon jets are identified through the b-tag method. A new physical quantity——hardness is defined, and the hardness distributions of quark and gluon jets are calculated. The dependence of the average multiplicity and average transverse momentum on hardness as well as the multiplicity and transverse momentum distributions in a certain hardness range in the quark and gluon jets are calculated respectively, and compared. It is found that the properties of quark and gluon jets are considerably different in these respects. The properties of quark jets are almost independent on hardness, while those of gluon jets have strong correlation with hardness. When H_d>10GeV the average multiplicity and average tranverse momentum of gluon jets are higher than those of quark jets; but when H-d<6GeV the results are reversed. This indicates that the conclusion on gluon jets being “fatter” than quark jets is valid only for hard gluons.

HTML

Reference (1)

Study of the Hardness Property of Quark and Gluon Jets

Abstract：

References

Access

Article Metrics

Metrics

通讯作者: 陈斌, bchen63@163.com

Email This Article