Charm hadron production at RHIC studied in combination model Motivation Quark combination model...
-
date post
21-Dec-2015 -
Category
Documents
-
view
219 -
download
0
Transcript of Charm hadron production at RHIC studied in combination model Motivation Quark combination model...
Charm hadron production at RHIC studied in combination model
• Motivation
• Quark combination model
• Results and discussions
• Summary
2008-7 HeFei China
Tao Yao, Wei Zhou, Qu-Bing XieDepartment of Physics, Shandong University
Motivation• One of the hot topics of both theory and experiment . * many theory papers: the charm flow, energy loss, production etc. * PHENIX and STAR collaborations have made many measurements. ◆ the binary scaling of ; STAR gives ~2 times bigger than PHENIX !
Two key ratios: ;
• Predictions for the upgrade of RHIC and for LHC• Important to accurately measure in future.• The hadronization mechanism can be tested at RHIC and LHC.
baryon enhancement
coalescence mechanism
charm baryon enhancement
different charm hadron ratios
different, /e cc
R 0 /D ccR effects on
NN
cc
NN
cc
?NN
cc
cc/ ( )/2
/e cc cce e
R N N 0 00/ ( )/2
/ccD cc D D
R N N
/J
The charm hadron ratios are hardly measurable directly now in experiments
Quark Combination Model (QCM) in AA
( ) (2 1) iri i i sC M J
( ) iri i sC B
( )M qq
( )B qqq
(4)fSU
quark new netN N N ( ), ( )Tf y f P: : : 1:1: :s c s cu d
N N N N
Nearest in rapidity axis Collinear
DecayPYTHIA6.4
F.L.Shao et al. P. R. C71, 044903, 2005 ; P. R.C75,034904,2007.
Rapidity and distribution
Tp
Final hadrons
Tp��������������
130 GeV: =0.75 mb, =41 mb, =965 (0-5%), 1862.4 GeV: =0.285mb, =36 mb, =904.3(0-5%), 7
5.5 TeV: =20 mb, =60 mb, =1303(0-10%), 343
• The number of pairs , as input in the QCM, is given by
The spectrum of charm quark at 200 GeV is inputted as a normalize
d form
Results and discussions
354.0)185.31()( 7.22 TTc ppf
(1)NN ppbin inelcc cc
N N
NN
cc
NN
cc
ccNpp
inel binNNN
cc
ccN
200 GeV STAR: =1.4 mb, =42 mb, =1065.4(0-5%), 36PHENIX: =0.622 mb, 16
NN
cc
ccNpp
inel binNNN
cc
ccN
ppinelppinel
binN
binN cc
N
ccNcc
Fig.1. The invariant spectra at 200 GeV for meson, inclusive electron, non-photonic electron and muon. The solid (dashed) line are from the by the STAR (PHENIX) coll.
TP
=8.33%
Assuming and
PHENIX has , whereas, we have
~12% enhancement of !
The newest data of decay branch ratio forare from PDGlive, give
~17% enhancement of !NN
cc
(2)
(3) ~ 2% difference of NN
cc
NN
cc
cceR
/
~67.7%
~32.3%
1. the parameter dependencec cV P
The dependences of some parameters for charm hadron ratios
charm decuplet baryons charm octet baryons
~100%
2. the parameter dependence: almost independentc cD O
3. the parameter dependences
Fig.3. The data and solid line are the same as Fig. 1, but the dashed line is from the input , the solid line is from .
88.0)185.31()( 12 TTc ppf
354.0)185.31()( 7.22 TTc ppf
Important for us to study their centrality dependence neglecting
the differences of radial flows
Important to study these ratios atvarious energies without the quark
spectra being well determinedTp
5. the c quark spectrum dependence: not sensitive Tp
Fig. 4. The centrality dependence for rapidity density of charm hadrons at 200 GeV
open binccN N N
NN ppbin inelcc cc
N N +
4/3bin partN N
+
.open
bin
dNconst
N dy
1/3openpart
part
dNN
N dy
consistent qualitatively with that of the Statistic Hadronization Model: P. L. B 571, 36 (2003)
6. the centrality dependence
' ' '/ / / / / /(4)
/ / / / / /open part open bin open cc
openopen part open bin open cc
dN dy N dN dy N dN dy NR
dN dy N dN dy N dN dy N
The centrality dependence for open charm hadron ratios
They are all independent of the centrality or !NN
cc
Then within coalescence/recombination framework
open binccN N N
7. The energy dependence for open charm hadron ratios
Note that Eq. (4) is still valid at different energy !Important for us to study the ratios at different energy, especially at LHC energy for large uncertainty of !
c cD Oc cV P
QC
M
the coalescence/recombination mechanism
the parameters ,
hadronizationmechanism
universal in AA
the strange suppress factor
the net
baryon number
factors vary with energy
ratios variance with energy
NN
cc
= 0.52, 0.48, 0.48, 0.48 = 0.859, 0.915, 0.927, 0.986(0.995)
Sdd
N N62.4, 130, 200 GeV RHIC
5500 GeV LHC
• The predictions of dependencies for the charm ratios , and
are given. The charm baryon enhancement in intermediate range, similar to that of ratio, is very prominent.
• The ratios in AA collisions are apparently different from those in reactions or annihilations, along with the newest decay data from PDG, the measured by PHENIX coll. will become larger up to ~17%.
• Systematically studied the dependencies of various parameters.
• Predictions of charm hadron ratios for the upgrade of RHIC and for LHC are given. They are important for precise measurement of in future and the hadronization mechanism for open charm hadrons can be tested.
Summary
Thank you all !
NN
cc
NN
cc
Tp
( )pp pee
/p
00 DD
cc
DD
cc
ss
cc
DD Tp
The invariant spectra for SU(3) mesons (left panel) and baryons (right panel) in top centrality at 200GeV.
TP
The invariant spectra for proton(left panel) and pion (right panel) at different centrality classes at 200 GeV
TP