1. Physics with the PANDA Detector at GSI
Diego Bettoni
Istituto Nazionale di Fisica Nucleare, Ferrara
First Meeting of the APS Topical Group on Hadronic Physics
Fermilab, 25 October 2004

2. Outline Overview of the Project PANDA Physics Program
Charmonium Spectroscopy
Hybrids and Glueballs
Hadrons in Nuclear Matter
The PANDA Detector Concept
Timeline
Conclusions
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3. The GSI FAIR Facility
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4. Storage and Cooler Rings
FAIR: Facility for Antiproton and Ion Research
Primary Beams
1012/s; 1.5 GeV/u; 238U28+
Factor over present in intensity
2(4)x1013/s 30 GeV protons
1010/s 238U73+ up to 25 (- 35) GeV/u
Secondary Beams
Broad range of radioactive beams up to GeV/u; up to factor in
intensity over present
Antiprotons GeV
Storage and Cooler Rings
Cooled beams
Rapidly cycling superconducting magnets
Key Technical Features
Radioactive beams
e – A collider
1011 stored and cooled GeV antiprotons
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5. Antiproton Physics Program
Charmonium Spectroscopy. Precision measurement of masses, widths and branching ratios of all (cc) states (hydrogen atom of QCD).
Search for gluonic excitations (hybrids, glueballs) in the charmonium mass range (3-5 GeV/c2).
Search for modifications of meson properties in the nuclear medium, and their possible relation to the partial restoration of chiral symmetry for light quarks.
Topics not covered in this presentation:
Precision -ray spectroscopy of single and double hypernuclei, to extract information on their structure and on the hyperon-nucleon and hyperon-hyperon interaction.
Electromagnetic processes (DVCS, D-Y, FF ...) , open charm physics
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6. The GSI p Facility HESR = High Energy Storage Ring
Production rate 2x107/sec
Pbeam = GeV/c
Nstored = 5x1010 p
High luminosity mode
Luminosity = 2x1032 cm-2s-1
p/p~10-4 (stochastic cooling)
High resolution mode
p/p~10-5 (el. cooling < 8 GeV/c)
Luminosity = 1031 cm-2s-1
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7. The PANDA Collaboration
More than 300 physicists from 48 institutions in 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
Spokesman: Ulrich Wiedner (Uppsala)
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8. QCD Systems to be studied in Panda
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9. Charmonium Spectroscopy
Charmonium is a powerful tool for the
understanding of the strong interaction.
The high mass of the c quark (mc ~ 1.5
GeV/c2) makes it plausible to attempt a
description of the dynamical properties of
the (cc) system in terms of non relativistic
potential models, in which the functional
form of the potential is chosen to reproduce
the known asymptotic properties of the
strong interaction. The free parameters in
these models are determined from a
comparison with experimental data.
Non-relativistic potential models +
Relativistic corrections + PQCD
2  s  0.3
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10. Experimental Study of Charmonium
e+e- annihilation
Direct formation only possible for JPC = 1-- states.
All other states must be produced via radiative decays of the vector states, or via two-photon processes, ISR, B-decay, double charmonium.
Good mass and width resolution for
the vector states. For the other states
modest resolutions (detector-limited).
In general, the measurement of
sub-MeV widths not possible in e+e-.
pp annihilation
Direct formation possible for all quantum numbers.
Excellent measurement of masses and widths for all states, given by beam energy resolution and not detector-limited.
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11. Experimental Method in pp Annihilation
The cross section for the process:
pp cc  final state
is given by the Breit-Wigner formula:
The production rate  is a convolution of the
BW cross section and the beam energy distribution function f(E,E):
The resonance mass MR, total width R and product of branching ratios
into the initial and final state BinBout can be extracted by measuring the
formation rate for that resonance as a function of the cm energy E.
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12. Hot Topics in Charmonium Spectroscopy - I
Discovery of the c(21S0) by Belle (+BaBar, CLEO).
Small splitting from . OK when
coupled channel effects included.
Discovery of new narrow state(s) above DD threshold X(3872) at Belle (+ CDF, D0, BaBar). c
c
M(c) =  4.4 MeV/c2
What is the X(3872) ?
Charmonium
13D2 or 13D3.
D0D0* molecule.
Charmonium hybrid
(ccg).
M =  0.6  0.5 MeV/c2
 2.3 MeV (90 % C.L.)
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13. Hot Topics in Charmonium Spectroscopy – II Observation of hc(1P1) by E835 and CLEO
e+e- 0hc c
hc c chadrons
pp hc c
C. Patrignani, BEACH04 presentation
A. Tomaradze, QWG04 presentation
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14. Charmonium States above the DD threshold
The energy region above the DD
threshold at 3.73 GeV is very poorly
known. Yet this region is rich in new
physics.
The structures and the higher vector states ((3S), (4S), (5S) ...) observed by the early e+e- experiments have not all been confirmed by the latest, much more accurate measurements by BES.
This is the region where the first radial excitations of the singlet and triplet P states are expected to exist.
It is in this region that the narrow D-states occur.
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15. Open Issues in Charmonium Spectroscopy
All 8 states below threshold have been observed: hc evidence stronger (E835, CLEO), 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 states must be found.
Decay modes of all charmonium states must be studied in greater detail: new modes must be found, existing puzzles must be solved (e.g. -), radiative decays must be measured with higher precision.
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16. Charmonium at PANDA
At 21032cm-2s-1 accumulate 8 pb-1/day (assuming 50 % overall efficiency)  104107 (cc) states/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 = 10-5 (GSI) vs 210-4 (FNAL)
Better detector (higher angular coverage, magnetic field, ability to detect hadronic decay modes).
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17. Hybrids and Glueballs
The QCD spectrum is much richer than that of the quark
model as the gluons can also act as hadron components.
Glueballs states of pure glue
Hybrids qqg E x o t i c l g h q 1 -- -+
2000
4000
MeV/ 2 10 -2
Spin-exotic quantum numbers JPC are
powerful signature of gluonic hadrons.
In the light meson spectrum exotic
states overlap with conventional states.
In the cc meson spectrum the density
of states is lower and the exotics can
be resolved unambiguously.
1(1400) and 1(1600) with JPC=1-+.
1(2000) and h2(1950)
Narrow state at 1500 MeV/c2 seen by
Crystal Barrel best candidate for glueball ground state (JPC=0++).
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18. Charmonium Hybrids
Bag model, flux tube model constituent gluon model and LQCD.
Three of the lowest lying cc hybrids have exotic JPC (0+-,1-+,2+-)
 no mixing with nearby cc states
Mass 4.2 – 4.5 GeV/c2.
Charmonium hybrids expected to be much narrower than light hybrids (open charm decays forbidden or suppressed below DD** threshold).
Cross sections for formation and production of charmonium hybrids similar to normal cc states
(~ 100 – 150 pb).
Excited gluon flux P
CLEO S
One-gluon exchange
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19. Charmonium Hybrids
Gluon rich process creates gluonic excitation in a direct way
ccbar requires the quarks to annihilate (no rearrangement)
yield comparable to charmonium production
2 complementary techniques
Production (Fixed-Momentum)
Formation (Broad- and Fine-Scans)
Momentum range for a survey
p ® ~15 GeV
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20. Heavy Glueballs Light gg/ggg systems are
complicated to identify (mixing).
Detailed predictions of mass spectrum
from LQCD
Exotic heavy glueballs:
m(0+-) = 4140(50)(200) MeV
m(2+-) = 4740(70)(230) MeV
Width unknown.
, , J/, J/ ...
Same run period as hybrids.
Morningstar und Peardon, PRD60 (1999)
Morningstar und Peardon, PRD56 (1997) 4043
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21. Hadrons in Nuclear Matter
Partial restoration of chiral symmetry in
nuclear matter
Light quarks are sensitive to quark condensate
Evidence for mass changes of pions and kaons has been deduced previously:
deeply bound pionic atoms
(anti)kaon yield and phase space distribution
(cc) states are sensitive to gluon condensate
small (5-10 MeV/c2) in medium modifications for low-lying (cc) (J/, c)
significant mass shifts for excited states:
40, 100, 140 MeV/c2 for cJ, ’, (3770) resp.
D mesons are the QCD analog of the H-atom.
chiral symmetry to be studied on a single light quark
theoretical calculations disagree in size and sign of mass shift (50 MeV/c2 attractive – 160 MeV/c2 repulsive)
vacuum
nuclear medium p K
25 MeV
100 MeV K+ K- p- p+
Hayaski, PLB 487 (2000) 96
Morath, Lee, Weise, priv. Comm. D-
50 MeV D D+
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22. Charmonium in Nuclei (1D) 20 MeV  40 MeV
Measure J/ and D production cross section in p annihilation on a series of nuclear targets.
J/ nucleus dissociation cross section
Lowering of the D+D- mass would allow charmonium states to decay into this channel, thus resulting in a dramatic increase of width
(1D) 20 MeV  40 MeV
(2S) .28 MeV  2.7 MeV
Study relative changes of yield and width of the charmonium states.
In medium mass reconstructed from dilepton (cc) or hadronic decays (D)
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23. The Detector Detector Requirements: For Charmonium:
(Nearly) 4 solid angle coverage (partial wave analysis)
High-rate capability (2×107 annihilations/s)
Good PID (, e, µ, , K, p)
Momentum resolution ( 1 %)
Vertex reconstruction for D, K0s, 
Efficient trigger
Modular design
For Charmonium:
Pointlike interaction region
Lepton identification
Excellent calorimetry
Energy resolution
Sensitivity to low-energy photons
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24. Panda Detector Concept
target spectrometer
forward spectrometer
straw tube tracker
mini drift chambers
muon
counter
DIRC
iron yoke
Solenoidal
magnet
electromagnetic calorimeter
micro vertex detector
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25. D. Bettoni - Panda at GSI

26. Timeline 2005 (Jan 15) Technical Proposal (TP) with milestones.
Evaluation and green light for construction.
2005 (May) Project construction starts (mainly civil construction).
Technical Design Report (TDR) according to
milestones set in TP.
High-intensity running at SIS18.
SIS100 tunnel ready for installation.
SIS100 commissioning followed by Physics.
Step-by-step commissioning of the full facility.
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27. Conclusions
The HESR at the GSI FAIR facility will deliver high-quality
p beams with momenta up to 15 GeV/c (√s  5.5 GeV).
This will allow Panda to carry out the following
measurements:
High resolution charmonium spectroscopy in formation experiments
Study of gluonic excitations (glueballs, hybrids)
Study of hadrons in nuclear matter
Hypernuclear physics
Deeply Virtual Compton Scattering and Drell-Yan
Hadron Physics has a brilliant future with PANDA at FAIR !
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