1. Open and Hidden Charm at PANDA
Tobias Stockmanns for the
PANDA collaboration
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

2. Charm an ideal testbench for QCD
Charm quark has large mass (~1.5 GeV), compared to the masses of u, d, s quarks;
Velocity of the charm quarks in hadrons is not too relativistic (v/c)2~0.2;
Strong coupling constant as(mc) is ~ 0.3.
Therefore:
Charmonium spectroscopy is a good testing ground for the theories of strong interactions:
QCD in both perturbative and nonperturbative regimes
QCD inspired purely phenomenological potential models
NRQCD and Lattice QCD
v/c depending on state
charm sector very attractive to test QCD
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

3. Charmonium Spectroscopy
Charmonium is a bound state of a cc. The QCD analog of positronium in QED
1 fm C
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

4. Charmonium Spectroscopy
Best understood region in charmonium spectrum - direct production in e+/e- annihilation  despite 30 years of measurements many parameters with poor precision
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

5. Charmonium Spectroscopy
Ground state with large uncertanties in mass and width
PDG2007
M(c) =  1.2 MeV/c2
(c) = 26.5  3.5 MeV
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

6. Charmonium Spectroscopy
h‘c seen 2002 by Belle with much higher mass than cristall ball (1986 : 3594 ± 5 MeV/c2) – later confirmed by CLEO and BaBar
PRL 89(2002)102001
h‘c
M(’c) = 3638  4 MeV/c2
(’c) = 14  7 MeV
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

7. Charmonium Spectroscopy
hc – very low statistics
width unknown
PRD 72(2005)032001
E835
New data from CLEO-c with much higher statistics
Cleo checken und einbauen
hc important for hyperfine splitting (should be 0)
M(hc) =  0.27 MeV/c2
(hc) < 1 MeV
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

8. Charmonium Spectroscopy
Region above DD-threshold – new possible charmonium states from Bell and BaBar
Z(3930) observed by Belle
Decay mode DD
JPC = 0++ or 2++
possible c‘c2
Y(3940) observed by Belle 2005
lower mass and smaller width measured by BaBar
would fit to 23P1
X(3943) observed by Belle 2007
would fit to h‘‘c
narrow D-wave states not observed
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

9. Charmonium Spectroscopy
Region above DD-threshold – new charmonium like states
X(3872) Belle 2003 confirmed by BaBar, CDF, D0
not charmonium
D0D*0 molecule ?
4 quark state ?
Y(4260) BaBar 2006 confirmed by Belle, Cleo-c
wcc1 molecule ?
hybrid meson ?
4 quark state ?
omega!
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

10. Charmonium Spectroscopy
Region above DD-threshold – new charmonium like states
Y(4350) BaBar 2007 recently confirmed by Belle
Z± (4430) Belle 2007 qq cannot create charged hidden charm. Smoking gun for:
4 quark state ?
meson molecule ?
Y(4660) Belle 2007 recently discovered
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

11. Open Issues in Charmonium Spectroscopy
All 8 states below threshold have been observed:
hc seen by CLEO with higher statistics, its properties need to be measured accurately.
The agreement between the various measurements of the c mass and width is not satisfactory. New, high-precision measurments are needed. The large value of the total width needs to be understood.
The study of the c has just started. Small splitting from the  must be understood. Width and decay modes must be measured.
The angular distributions in the radiative decay of the triplet P states must be measured with higher accuracy.
The entire region above open charm threshold must be explored in great detail, in particular:
the missing D-wave states must be found
the newly discovered states understood (cc, exotics, multiquark, ...)
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

12. Open Charm Spectroscopy
D spectroscopy is the QCD analogon to hydrogen atom
Narrow states Ds0(2317) and Ds1 (2458) recently discovered at B factories do not fit theoretical calculations.
Quantum numbers for the newest states DsJ(2700) and DsJ (2880) open
At full luminosity at p momenta larger than 6.4 GeV/c PANDA will produce large numbers of DD pairs.
Despite small signal/background ratio (510-6) background situation favourable because of limited phase space for additional hadrons in the same process.
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

13. Tobias Stockmanns, FZ Jülich
Why antiprotons?
e+e- → y’
→ gc1,2
→ gge+e-
→ ggJ/y
Production:
→ gJ/y
→ ge+e-
pp→ c1,2
Formation:
e+e- annihilation via virtual photon: only states with Jpc = 1-- (to first order)
3500
3520 MeV
3510
CBall ev./2 MeV
100
ECM
CBall
E835
1000
E 835 ev./pb
cc1
Measured rate
Beam
Resonance cross section
CM Energy
In pp annihilation all mesons can be formed
!e+e- Luminosity <-> pp!
Resolution of the mass and width is only limited by the beam momentum resolution
Br(e+e- → y) ·Br(y → ghc) =
Br(pp → hc) =
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

14. Detailed simulation studies
As an example: width of Ds0*(2317) in reaction ppDsDs0*(2317)
very preliminary
Method:
energy scan around threshold
count signal events
determine excitation function
extract width
Tobias Stockmanns, FZ Jülich 14
Hadron 2007, 12. October 2007

15. Tobias Stockmanns, FZ Jülich
Physics Reach
At 21032cm-2s-1 accumulate 8 pb-1/day (assuming 50 % overall efficiency)  (cc) states/day.
pp Y(3770)D+D- (~3 nb)  K+/-p-/+p-/+ (~30 pb)  240 counts/day
Total integrated luminosity 1.5 fb-1/year (at 21032cm-2s-1, assuming 6 months/year data taking).
Improvements with respect to Fermilab E760/E835:
Up to ten times higher instantaneous luminosity.
Better beam momentum resolution p/p = 4x10-5 (HESR) vs 210-4 (FNAL)
Better detector (higher angular coverage, magnetic field, ability to detect hadronic decay modes).
Fine scans to measure masses and widths to  100 keV
Explore entire region below and above open charm threshold.
Decay channels
J/+X , J/  e+e-, J/  m+m- gg
hadrons DD
Mehr konkrete Simulationsergebnisse von PANDA
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

16. Tobias Stockmanns, FZ Jülich
Main Physics Program
PANDA – AntiProton Annihilations at Darmstadt
qq potential in the charmonium system
precision measurements of cc-states (not only JPC = 1--) cc above DD-threshold  measurement of D-mesons
Search for Hybrids qqg and/or Glueballs gg
Spectroscopy of new charm states
Charmed and multi-strange baryon spectroscopy
EM Endzunstände
Spektroscopy von neuen Charmzuständen
Electromagnetic processes (ppe+e-, ppgg, Drell-Yan)
Properties of single and double hypernuclei
Properties of hadrons in nuclear matter
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

17. High Energy Storage Ring
Detector
Electron
cooler
E<8 GeV
Injection
Pmax = 15 GeV/c
High resol. Mode: L = cm-2 s-1 p/p < 4x10-5
High lum. Mode: L = 2·1032 cm-2 s-1 p/p < 10-4
Cooling: electron/stochastic
HESR
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

18. Tobias Stockmanns, FZ Jülich
PANDA Spectrometer
Detector requirements:
4p coverage (partial-wave-analysis)
high rates (107 annihilations/s)
good PID (g, e, m, p, K, p)
momentum res. (~1%)
vertexing für D, K0S, L (ct = 123 mm for D0, p/m »2)
efficient trigger (e, m, K, D, L)
no hardware trigger (raw data rate ~TB/s)
Tobias Stockmanns, FZ Jülich 18
Hadron 2007, 12. October 2007 18

19. Tobias Stockmanns, FZ Jülich
PANDA Spectrometer
Tobias Stockmanns, FZ Jülich 19
Hadron 2007, 12. October 2007

20. PANDA Spectrometer Pellet or cluster jet target
Dipole magnet for forward tracks
Solenoid magnet for high p t tracks:
Superconducting coil & iron return yoke
Tobias Stockmanns, FZ Jülich 20
Hadron 2007, 12. October 2007

21. Forward Drift Chambers Tobias Stockmanns, FZ Jülich
PANDA Spectrometer
Silicon Microvertex
Central Tracker
Forward Drift Chambers
Tobias Stockmanns, FZ Jülich 21
Hadron 2007, 12. October 2007

22. Tobias Stockmanns, FZ Jülich
PANDA Spectrometer
Muon Detectors
Forward RICH
Barrel DIRC
Barrel TOF
Endcap DIRC
Forward TOF
Tobias Stockmanns, FZ Jülich 22
Hadron 2007, 12. October 2007

23. Tobias Stockmanns, FZ Jülich
PANDA Spectrometer
PWO Calorimeters
Forward Shashlyk EMC
Hadron Calorimeter
Tobias Stockmanns, FZ Jülich 23
Hadron 2007, 12. October 2007

24. Tobias Stockmanns, FZ Jülich
Requirements MVD
Good spatial resolution in r-phi  momentum measurement of soft pions from D* decays
Good spatial resolution especially in z  D-tagging
Good time resolution (O(20 ns))  ‘DC’-beam (107 events/s)
Low material  low momentum particles
Amplitude measurement  dE/dx for particle identification
Modest radiation hardness (1014 neq / cm2)
Moderate occupancy
Triggerless readout  no first level hardware trigger
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

25. Micro-Vertex-Detector
40 cm
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

26. Technology options considered
New readout electronics in 130 nm technology (INFN Torino)
Thin electronics 50 µm
Thin ( µm) epitaxial silicon sensor
„Edgless“ sensors
3D-Integration of sensor and readout electronics
Optical data readout as early as possible
Serial powering
Full carbon support structure
Use of new carbon foam materials
Tobias Stockmanns, FZ Jülich 26
Hadron 2007, 12. October 2007

27. Tobias Stockmanns, FZ Jülich
Summary
Charm physics is one of the hot topics within the hadron physics community
The B-factories have produced many new states which do not fit into the standard picture of charmonium or open charm
To pin down the characteristics of these new states and to discovere the missing ones the future PANDA experiment with its high momentum anti-proton beam is the ideal tool
last point bigger
!Less text!
Method from Albrecht M2 vs sqrt s
Simulation results from Klaus Götzen
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

28. Tobias Stockmanns, FZ Jülich
PANDA collaboration
Basel, Beijing, Bochum, Bonn, Brescia, Bucharest, Catania, Cracow, Dresden, Dubna, Edinburgh, Erlangen, Evanston, Ferrara, Frankfurt, Frascati, Genova, Gießen, Glasgow, GSI, Helsinki, Jülich, Katowice, Lanzhou, Mainz, Milano, Minsk, München, Münster, Novosibirsk, Orsay, Pavia, Protvino, St. Petersburg, Stockholm, Tomsk, Torino, Trieste, Tübingen, Uppsala, Valencia, Warsaw, Wien, Mumbai, Moscow,
17 countries – 55 institutes – 450 scientists
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007

29. Central Tracker – 2 options
Time Projection Chamber
Straw Tube Tracker
1 m
1 cm
Tobias Stockmanns, FZ Jülich
Hadron 2007, 12. October 2007