Transcript PowerPoint 演示文稿 - Istituto Nazionale di Fisica

The 3rd Workshop on Heavy Quarkonium, Oct. 12-15, Beijing
 
e
The Color Octet Effect from e  J /  X  
Factorry
at B
Jian-Xiong Wang
IHEP, Beijing
1. Brief Introduction to FDC-NRQCD package
2. Motivation
3. Uncertainty in the theoretical treatmeant J
for/
 
4. The results for e e  J /  X  
5. Conclusion
production
1. Brief Introduction to FDC-NRQCD package
Feynman Diagram Calculation(FDC), This project was started at
1993.
FDC homepage:
http://www.ihep.ac.cn/lunwen/wjx/public_html/index.html
FDC-SM-and-Many-Extensions
FDC-NRQCD
FDC-MSSM
FDC-EMT
FDC-PWA
Written in REDUCE,
RLISP and C++.
To create Fortran.
FDC System
Input for physical model
Physical model evaluation
Input for physical process
Choose physical model
and processes
Feynman diagram
generation
Amplitude manipulation
Full Feynman Rules
Counter-terms
Physical parameters
Treatment of kinematics
Numerical integration
Latex version of then
model
Numerical results &
Required plots in
Hbook format
FIG.1: FDC system flow chart
3. FDC-NRQCD
Hevay Quark Meson: J/psi, B_c, ......
S-wave, P-wave
Color-singlet, Color Octet
NRQCD Formulation
Fwuvy Theorem
Color Factor
Gauge Invariant Check
NRQCD calculations performed by using FDC-NRQCD package
e   e   J /  X
e   e   J /  X  


e  e  J /  c  c
P  P  J /  X
Presented in this talk,
Hep-ph/0311292
C.F. Qiao and J. X. Wang,
PRD 69, 014015,2004
At Tevatron, Presented in C. F. Qiao’s talk
P  P( p )  Bc ( 3PJ 0,1,2 ,1P0 )  b  c At Tevatron and LHC, will presented
in C. H. Chang’s talk
P  P( p)  Bc  b  c  g
………….
Is the largest calculation performed
by using FDC-NRQCD until now.
Calculation of One Physical Process
●
>process_cp old new
●
>diag
●
>amp
●
>kine
●
>cd fort
●
>make
●
>int
Examples for integrated multi-processes calculation tool
The Problem for the universal NRQCD matrix elements
P  P  J /  X
CDF Collaboration, F.~Abe {\it et al.}
PRL. 69, 3704 (1992);79, 572 (1997);
79, 578 (1997);
e   e   J /  X
BABAR Collaboration, B.~Aubert et al.,
PRL. 87, 162002 (2001).
BELLE Collaboration, K.~Abe et al.,
PRL 88, 052001 (2002).
The measurement of the J/\psi$ production at B factory in BaBar
and Belle experiments\cite show that the theoretical predication
E. Braaten and Y. Q. chen, PRL 76, 730 (1996)
Peter Cho, Adam K. Leibovich, PRD 53, 6203 (1996);
PRD54, 6690 (1996).
For $p^*_{J/\psi}$ spectra did not agree with experimental results,
The color octet processes only contribute to the endpoint of $p^*_{J/\psi}$
Spectra due to the kinematics of the two body final state. But the
experiments did not observe the this signal.
To explain this discrepancy, it is nature to think that $J/\psi^{(8)}$
have to hadronize into color singlet $J/\psi$ and will lose it's energy
such as the case when a quark jet hadronize into hadrons. Therefore
there should be a hadronization possibility function $F(x,...)$ for $J/\psi$
production with momentum $p_{J/\psi}=x~p_{J/\psi^{(8)}}$ and
$\int^1_0dx~F(x,...)=1$. The universal NRQCD matrix elements
treatment is just a first step approximation of $F(x,...)=\delta(1-x)$.
S.~Fleming, A. K. Leibovich and T. Mehen.[arXiv:hep-ph/0306139].
tried on it for the $J/\psi$ production at B factory and broadened
the $p^*$ spectra from color octet $J/\psi$.
The numerical results of the total cross section
For Color-Singlet:
 ( e  e   J /  X )  0.233 pb,
 (e  e   J /  X   )  0.128 pb,
For Color-Octet:
 (e  e   J /  X )  0.2 pb
 (e  e   J /  X   )  0.445 pb,
Where the condition E  100 MeV for hard photon is used.
The reason is very clear that the following cross sections increase when
the center mass energy of e  e  go down from 10.6GeV to 5GeV.
e  e   J /  cc will closed.
e  e   J /  gg increase 4 times
e  e    (8) [ 3PJ ]  g
increase 51 times
e  e    (8) [1S 0 ]  g increase 17 times
The results for e  e   J /  X  
 (e  e   J /  X   , color  sin glet )  128 fb,
 (e  e   J /  X   , color  octet )  445 fb,
The results for e  e   J /  X   with cut-off
 (e  e   J /  X   , color  sin glet )  13 fb,
 (e  e   J /  X   , color  octet )  42 fb,
The Property of the E Spectrum:
1. It is hardly changed even if there is lage QCD correction.
2. It can not be changed by the procedure of J / ( 8) and gluon
handronization into J / and handron.
3. It is very clearly separate the color octet and color singlet signal.
4. Another advantage is that the color octet cross section is even
61% large than it’s Born one.
Conclusion
A good way is shown to clarify the situation of the
Color-Octet Mechanism for J / production:
To measure the E Spectrum in the initial state radiation
Process e  e   J /  X   ,
uncertainty from J / (8)  g
QCD correction.
It could avoid the
handronization and