1. Physics with open charm mesons at
Andrey Sokolov
Institute of Nuclear Physics,
Research Center Jülich, Germany
Outline:
Physics foundations;
Experimental techniques;
Capabilities of the
Summary.
The structure and dynamics of hadrons
International Workshop XXXV on Gross Properties of Nuclei and Nuclear Excitations,
Hirschegg, Kleinwalsertal, Austria, January , 2007

2. Panda Physics Overview
Charmonium spectroscopy:
Precision M and Γ measurement: qq – potential.
New states above DD threshold.
Charmed hybrids and glueballs;
Interaction of charmed particles with nuclei;
Hypernuclei;
Further options:
Open charm physics
Wide angle compton scattering;
Baryon-Antibaryon production;
CP-Violation (Λ,D).
Andrey Sokolov

3. Charmonium spectroscopy
The energy region above the DD threshold is very poorly known:
The higher vector states ((3S), (4S), (5S) ...) have not all been confirmed by the latest measurements by BES.
In this region the narrow D-states are expected!!!
Andrey Sokolov

4. Charmonium Spectroscopy
A new narrow resonance called X(3872) was observed in 2003:
by CDF
11.6 s effect
X(3872)
10 s effect
y’ppJ/y
by BELLE
M = ± 0.6 ±0.5 MeV
G < 2.3 MeV at 90% C.L.
The other states Y(3940), Y(4260), X(3943), Z(3934), ψ(4320) have been observed in recent years
Andrey Sokolov

5. Open Charm Spectroscopy
In Heavy-Light systems
like H-atom;
ordered by property of the light quark;
approximate j degeneracy;
the large gap between j=3/2 and j=1/2 was unexpected.
j=L+sL
J=j+sH
m [GeV/c2]
Ds1
}j=3/2
D*K
Ds2*
}j=1/2
DsJ
(2458)
D0K
DsJ*
(2317)
Ds*
The Ds± Spectrum
|cs> + c.c. was not expected to reveal any surprises, but… Ds
in 2003 BaBar and CLEO observed two new narrow Ds mesons with surprisingly low masses. 0- 1- 0+ 1+ 2+ 3- JP
Andrey Sokolov

6. (cs) – A Heavy-Light System
Andrey Sokolov

7. } Production mechanism e+e- interactions: pp reactions:
Only 1-- states are directly formed;
Other states require:
ISR;
B meson decays;
higher order process (γγ fusion).
pp reactions:
All meson states directly formed (very good mass resolution)
other states can be studied using production mechanism. }
low cross-section, mass resolution determined by detector performance
ECM
Andrey Sokolov

8. Energy dependency of cross section for HH
Effect of finite momentum spread
Andrey Sokolov

9. Benchmark Channels Analysis
Following reaction were chosen to demonstrate the physics performance of the PANDA detector:
Andrey Sokolov

10. Production cross-section
The production cross-section was estimated using the Breit-Wigner formula:
as a result the maximum total cross-section is:
and the signal to background ratio is:
Andrey Sokolov

11. Proposed PANDA Detector
beam
Andrey Sokolov

12. Micro-Vertex Detector
Displaced vertices of open charm and strangeness with precision ~ 70 μm;
Build on ATLAS experience with hybrid detectors;
Silicon pixel (2-4 layers) and strips (2 layers);
~7.2 million barrel pixels, ~2 million forward pixels;
R&D:
Requirements on pixel size and orientation;
Investigate photon conversions;
Electronics.
Andrey Sokolov

13. Micro-Vertex Detector
400mm
300mm
Andrey Sokolov

14. Simulation of ψ(3770) Selection criteria:
Kaon ID (only by DIRC and RICH);
D-meson invariant mass;
D-meson secondary vertex fit;
Kinematical constrain on ψ(3770) mass;
Missing mass selection (Invariant mass resolution σ=10MeV).
Single D-meson reconstruction efficiency - 26%;
ψ(3770) reconstruction efficiency - 4.2%;
Background suppression factor - 2×109;
Signal/background ratio ~ 3.
Andrey Sokolov

15. Reconstruction of D and Ds mesons
Decay
Br, [%]
Efficiency, [%]
9.2 26
3.8 25
7.5 8
4.4
~28*
* Only one kaon identification is required.
Andrey Sokolov

16. Total Reconstruction Efficiency
Reaction
Efficiency, [%]
4.2
3.6
0.92
4.6*
3.3*
* Only one kaon identification is required.
Andrey Sokolov

17. Summary
There are many open questions for open charm and charmonium above the DD threshold.
The PANDA detector will perform high resolution spectroscopy with p-beam and provide new data on this topic.
The Micro-Vertex Detector was designed for the reliable detection of D-mesons and its decay products.
Simulation results demonstrate the good reconstruction efficiency for D-mesons.
Very high background suppression is achieved.
Andrey Sokolov

18. Panda Participating Institutes
more than 300 physicists (48 institutes) from 15 countries:
U Basel
IHEP Beijing
U Bochum
U Bonn
U & INFN Brescia
U & INFN Catania
U Cracow
GSI Darmstadt
TU Dresden
JINR Dubna (LIT,LPP,VBLHE)
U Edinburgh
U Erlangen
NWU Evanston
U & INFN Ferrara
U Frankfurt
LNF-INFN Frascati
U & INFN Genova
U Glasgow
U Gießen
KVI Groningen
U Helsinki
IKP Jülich I + II
U Katowice
IMP Lanzhou
U Mainz
U & Politecnico & INFN Milano
U Minsk
TU München
U Münster
BINP Novosibirsk
LAL Orsay
U Pavia
IHEP Protvino
PNPI Gatchina
U of Silesia
U Stockholm
KTH Stockholm
U & INFN Torino
Politechnico di Torino
U Oriente, Torino
U & INFN Trieste
U Tübingen
U & TSL Uppsala
U Valencia
IMEP Vienna
SINS Warsaw
U Warsaw
Andrey Sokolov

19. New Charmonium Resonances
X(3872), Belle 09’2003, 1++, χc1´ or D0D* molecule
decays into J/ψπ+π-, J/ψπ+π-π0, J/ψγ, D0D*
Y(3940), Belle 09’2004, JP+, 23P1 or Hybrid??
decays into J/ψω
Y(4260), BaBar 06’2005, 1--, 23D1 (BaBar) or 43S1 (CLEO) or Hybrid
decays into e+e-, J/ψπ+π-, J/ψπ0π0, J/ψK+K-
X(3943), Belle 07’2005, 0-+, ηc´´
decays into D0D*
Z(3934), Belle 07’2005, 2++, χc2´
decays into γγ, DD
ψ(4320), BaBar 06’2006, ?, Hybrid
Andrey Sokolov

20. Threshold Measurement
p p  X X : _
at threshold:
far above threshold:
 ratio depends only on G, M, and s
A. Gillitzer
Andrey Sokolov

21. Facility for Antiproton and Ion Research
HESR
100 m
Andrey Sokolov

22. High Energy Storage Ring
from RESR
Storage ring for p:
Np = 5×1010, Pbeam= GeV/c;
High density target:
pellet 1015 atoms/cm3, cluster jet, wire;
High luminosity mode:
Δp/p = 10-4, stochastic cooling, L = 1032 cm-2s-1;
High precision mode:
Δp/p = 3×10-5, electron cooling, L = 1031 cm-2s-1.
Andrey Sokolov

23. Simulation of the D-mesons
Vertex position
Invariant mass of D - meson
1000 decays were simulated:
Here D-mesons decayed at the point (0.1,0.1,0.4)mm.
Kaon ID was required.
Three tracks were refitted to the common vertex.
Andrey Sokolov

24. ψ(3770) Invariant Mass Resolution
σ(Minv) = 10 MeV
Andrey Sokolov