1、1,强子对撞机上的B物理研讨会,Hadronic Production of Bc(B*c) Meson Induced by the Heavy Quarks inside the Collision Hadrons,吴兴刚 ( Xing-Gang Wu )(ITP),In colarboration with Profs. Z.X. Zhang, C.F. Qiao and J.X. Wanghep-ph/0509040,2,Calculation Technology-GM-VFN Scheme,Results Under the GM-VFN and Comparison with t
2、he Original FFN results,Background,A Simple Discussion and Summary,Contents,3,Bc Meson Experimental observation (CDF & D0) Lifetime , mass mBc Decays and Production (hadronic)Special Interests The decay possibilities for the two heavy flavor comparable Vcb2 mb5/Vcs2 mc5O(1) (annihilationfBc2Vcb2 ) T
3、o study two flavor simultaneously (Vcb, Vcs) To be a source of precisely tagged Bs mesons, to observe c0, c1, c2 and hc etc via Bc weak decay etc.,1. Background,2005,A) Why we need to study Bc,4,Mechanisms for the hadronic production A) Gluon-gluon fusion - dominant color-singlet: S-wave: Bc ( 1), B
4、c*(2.6); P-wave: Bc*( 0.5) color-octet: S-wave: Bc+Bc* (0.2) B) Quark-antiquark annihilation -must be light quark color-singlet: S-wave: Bc+Bc* (0.1) C) Gluon + c-quark (anti-b) - intrinsic c or b-GM-VFN scheme color-singlet: S-wave: Bc, Bc* (1) in small pt regions,Our main concern is the hadronic p
5、roduction,BCVEGPY,5,B) Present Status of BCVEGPY,ATLAS (ANTNA?) - in collaboration with Prof. Z.X. Zhang, Chafik Driouichi and P. Eerola (Lund U.),CMS (SIMUB) - in collaboration with Prof. Z.X. Zhang, G.M. Chen, S.H. Zhang, A.A. Belkov and S. Shulge (IHEP),D0 - in collaboration with Prof. Z.X. Zhang
6、, Y.Jiang, N. Han and W.G. Ma (CUST),TEVATRON RUN II - Generated data used in hep-ex/0505076 (new results of CDF) for analyzing data, with Vaia Papadimitriou,BCVEGPY2.0 ( High efficiency ! ),6,C) Why studying the intrinsic mechanism ?,In most of the present calculations, extended FFN scheme is appli
7、ed. Including BCVEGPY. Prof.Qiao has studied the intrinsic charm mechanism to the hadronic production of J/Psi.Interesting to study its function to the hadronic production of Bc. Lower order in s and the phase space distribution compensate its higher order in PDF.,D) Why GM-VFN scheme and not FFN ?,
8、The mass effects can be consistent treated in both PDF and hard scattering amplitude.The double counting of gluon-gluon fusion and intrinsic mechanism can be treated well.,2. Calculation Technology-GM-VFN Scheme,8,Subtraction method in GM-VFN scheme,Intrinsic mechanism,9,Comparison of evolved PDF an
9、d perturbative PDF (SUB),10,11,For hadronic production, we always include a small pt cut, so the fifth term shall be studied here,12,Subtraction method,3. Results Under the GM-VFN and Comparison with the Original FFN results,13,Total cross-section for Bc,14,Total cross-section for Bc*,15,Pt distribu
10、tions at LHC,16,Pt distributions at TEVATRON,17,Comparison between GM-VFN and FFN at LHC,18,Comparison between GM-VFN and FFN at TEV,19,A Rough comparison of GM-VFN and FFN,20,GM-VFN,Strict FFN,Extended FFN,LHC 1S0,LHC 3S1,TEV 3S1,TEV 1S0,21,GM-VFN,GM-VFN gluon only,FFN,LHC 1S0,LHC 3S1,TEV 3S1,TEV 1
11、S0,22,4. A Simple Discussion and Summary,GM-VFN: consistent treat the mass effects and deal well with the double counting problem.,Intrinsic production may give sizable contribution in comparison with the gluon-gluon fusion mechanism.,Intrinsic production is sizable in small pt region ( 7GeV) and th
12、en drops fast.,GM-VFN and FFN results are very close to each other at large pt region. Main difference is in small pt region.,The old FFN results still are reliable, especially in the large pt regions.,23,Backup Slides For BCVEGPY,24,The Whole Flowchart for BCVEGPY,25,BCVEGPY2.0 designed for all the
13、 considered color-singlet/octet S-wave and P-wave states. The flow chart is quite the same as that of the first version BCVEGPY1.0.,TWO MORE:IMIXIMIXTYPE,26,Derivation of Bc Meson Generator BCVEGPY1.0,S-Wave ProductionHelicity Amplitude,27,Unit the Same Type Terms As Much As Possible,find out all th
14、e independent fermion lines without taking into account the color factor and the scalar part of the propagator,with these independent fermion lines construct all the necessary QED-like Feynman diagrams,using basic QED-like Feynman diagrams, with the help of the gluon-gluon and quark-quark symmetry,
15、construct all the QED-feynman diagrams. And decompose all the QCD-like diagrams to be QED-like and also expand over the basic QED-like diagrams.,consider the color factors and the scalar part of the proporgator and get the whole helicity amplitude. Arrange all the different helicity amplitudes in a
16、proper order for easy programming.,Choose proper way to calculate the fermion line,Schematic Steps For the Improved Helicity Approach,28,The amplitude of the P-wave production involve the derivation over the relative momentum of the constituent quark, so other than taking the helicity approach as ha
17、s been done in the S-wave case, we take FDC program to do such kind of work for the P-wave production.,Amplitudes for color-Octet S-wave states,Improved Helicity amplitude approach !The main difference for color-singlet S-wave is the color flow,Derivation of Bc Meson Generator BCVEGPY2.0,Amplitudes for color-Singlet p-wave states,
