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Charmonium Dynamicsat
Thresholds
H. Lenske
Institut für Theoretische Physik, JLU Giessen
and
GSI Darmstadt
2
Agenda:
• Charmonium Spectroscopy
• Charmonium Production
• Physics Content of Line Shapes
3
Charmonium at the DD-Threshold
• Closed quarkonic channels: confined cc states• Closed hadronic channels : sub-threshold DD-states• Open hadronic channels : DD-channels
4
Charmonium Spectroscopy in the Quark Model
5
Quarkonium: Confined Systems of Heavy (cc,bb) Quarks
cc
e- e+
6
Charmomium Spectrum in the Quark Model
0
4( ) ( , )
3Breit s
hyperfineV r V r V rr
J. Lopez, H.L., 2014
• Unified description of D-mesons and Charmonium• Spectra, wave functions, form factors…
7
Charmonium Production and Spectroscopy at the Threshold
8
The „BIC“-view of Continuum Spectra
• Closed channel E* is embedded into a continuum of open channels• E* decays only via interaction V(r) with open channels
BIC - Bound State Embedded into the Continuum Scale-independent, universal phenomenon
BIC{
9
• Quark model description of charmonium and D-mesons• „3P0“ Lagrangian for pair creation in ccD(cq)D(qc) coupling
gm h.c. 30
q q qPL
Charmonium Wave Function at the DD Threshold
3 1c b b k DD
b DD
3 3 31 1 1
0 0 *0 0
~ z (cc) d k z k
e.g. b= '(3686)2 S , ''(3770)1 D , '''(4040)3 S ...
DD=D D ,D D ,D D ...
10
Channel Coupling and the 13D1 cc Component of y(3770)
2 1( ) Im ( )
JS G
1
( ) 1 ( )P
Spectral Distribution Spectral Factor
11
DD elastic scattering: total p-wave cross sectionIsoscalar 2p and vector meson exchange plus channel coupling
12
Charmonium Production Scenario:Coherent cc and DD production
Quarkonic HadronicProduction Form Factor
13
Spectral Properties of cc-States(Cornell-Breit Potential)
Quark Model predictions for e+e- width and 3D1 suppression:
14
3 1c b b k DD ~ z (cc) d k z k
Wave Function at the Charmonium Threshold
Single confined channel b=y(13D1) and single open channnel s=DD:
} }
Quarkonic„hard“ component
Hadronic„soft“ component
15
Production Cross Sections at the Charmonium Threshold
2
rDD 2
r
q cote e DD ~
1 cot
c sr1
cDD
| T | e e x ( ) q= ; cot
x ( )k | T | e e
Single confined channel c=y(13D1) and single open channnel s=DD:
2
( )1
c s
qM T
16
2
rDD 2
r
2 3 21F DD
DD DD5/2
20R
r R R RR R
q cote e DD ~
1 cot
8 kk T e e
3s
m scot ; m m m (s)
m (s)
Charmonium Production@BES III and PANDA:BIC and Fano-Resonances
The line shape parameter:
b
1DD
(cc) | T | e e q=
k | T | e e
• Controlling the line shape asymmetry • Indicator of the reaction scenario: quarkonic vs.
hadronic
Xu Cao, H. L., arXiv:1408.5600 [nucl-th]
DD-Dynamics at Threshold Channel Coupling and the Line Shape of y‘‘(3770)
17
0 0D D threshold
3729.7 MeV
D D threshold
3739.2 MeV
3.65
(2s / 3686)
X(3900) ??
q=-2.1±0.3
18
Line Shape of Reaction Form Factor and Physics Content
cc
DD
| T | Quarkonic q= ~ e e , pp ,...
k | T | Hadronic
q=-0.2 q=-1 q=-10
Dominance of hadronic
production
balanced quarkonic and
hadronic production
Dominance of quarkonic production
• Line shape controlled by quarkonic content • Line shape depends on production reaction• Spectral distribution of the SAME final state depend on initial state
cc
cc
cc
19
Production of y‘‘(3770) and the DD Spectral Distributions
(Data: BES Collaboration)
Derived Parameters:
Xu Cao, H.L., 2015
20Science 340,716 (2013)
Laser-Modelling of Fano-Line Shapes
Defining features of Fano-Resonances:
Asymmetric line shapes and GR<<mR
21
Summary and Outlook
• Charmonium Spectroscopy
• Dynamics of charmonium production in (e+,e-), (p,p)…
• Resonances, closed and open channels
• Charmonium cross sections and spectral distributions
• Physics content of charmonium line shapes
• Charmonium production and spectroscopy at PANDA
• Production of charmed baryons at PANDA
Credits to Xu Cao, Juan Lopez, and Radhey Shyam