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21 - 26 Aug 2005, Rio de Janeiro, Brazil

21 - 26 Aug 2005, Rio de Janeiro, Brazil. The PANDA project at GSI. PANDA. anti P roton AN nihilation at DA rmstadt. PANDA. PANDA is an experiment that will use a very high intensity p beam with momentum from 1.5 GeV/c up to 15 GeV/c on a fixed proton target :

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21 - 26 Aug 2005, Rio de Janeiro, Brazil

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  1. 21-26 Aug 2005, Rio de Janeiro, Brazil The PANDA project at GSI

  2. PANDA antiProton ANnihilation at DArmstadt

  3. PANDA PANDA is an experiment that will use a very high intensity p beam with momentum from 1.5 GeV/c up to 15 GeV/c on a fixed proton target : √s from 2.25 up to 5.47 GeV It will continue and extend the successful physics program initiated at facilities like LEAR at CERN and FERMILAB

  4. Physics topics covered in PANDA • Charmonium • Exotics : hybrids, glueballs and other exotics • Mesons in nuclear matter • Charmonium absorption in nuclear matter • Hypernuclear physics • Open charm factory : CP violation, and D physics • Crossed-channel Compton scattering and related exclusive processes • Electromagnetic form factors of the proton in the time-like region

  5. The PANDA collaboration

  6. PANDA Collaboration • At present a group of 340 physicists from47 institutions of 16 countries Austria – Belaruz - China - Finland - France - Germany – Holland - Italy – Poland – Romania-Russia – Spain - Sweden – Switzerland – U.K. – U.S.A.. Basel, Beijing, Bochum, Bonn, IFIN Bucharest, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, KVI Groningen, GSI, Inst. of Physics Helsinki, FZ Jülich, JINR, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern, BINP Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, Stockholm, Dep. A. Avogadro Torino, Dep. Fis. Sperimentale Torino, Torino Politecnico,Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU Warsaw, AAS Wien Spokesperson: Ulrich Wiedner – Uppsala deputy Paola Gianotti, INFN-LNF

  7. The PANDA experimental site at the Gesellschaft für Schwer Ionenforschung (GSI) facility in Darmstadt - Germany

  8. The PANDA experiment site within FAIR High Intensity Mode: Luminosity 2x1032 cm-2s-1 (2x107Hz) dp/p (st. cooling) ~10-4 High Resolution Mode: Luminosity 2x1031 cm-2s-1 dp/p (electron cooling) ~10-5 For a detailed description of the FAIR facility project at GSI see talk by K. Peters on Monday morning plenary session

  9. The PANDA detector

  10. The PANDA detector • Detector requirements • full angular acceptance and angular resolution for charged particles and g, p0 • particle identification (p, K , e, m) in the range up to ~ 8 GeV/c • high momentum resolution in a wide energy range • high rate capabilities, especially in interaction point region and forward detector : • expected interaction rate ~ 107

  11. The PANDA detector Target region Spectrometer • beam of p of momentum from 1.5 up to 15 GeV/c • proton pellet target (or gas jet target) • Micro Vertex Detector • Inner Time of Flight detector (still under discussion) • Tracking detector : Straw Tubes Tracker or TPC • DIRC • Electromagnetic Calorimeter • 2 Tesla solenoid • scintillation muon counters • 2 stations of Multiwire Drift Chambers also wire targets or foil targets for nuclear target physics carbon target interleaved with silicon detector for hypernuclear physics

  12. Forward Spectrometer The PANDA detector Top View • 6 stations of Multiwire Drift Chambers • analysing dipole : 2 Tesla·meter • Forward DIRC and RICH • Forward Electromagnetic Calorimeters • Time of Flight counters • Hadron Calorimeter

  13. The PANDA detector

  14. The pellet target • To achieve design luminosity required effective target thickness of 3.8x1015 atoms/cm2 • Frozen droplets of hydrogen (pallets) successfully operating at CELSIUS/WASA facility • very close now to requirements (2.8x1015 atoms/cm2), still working to reach goal • pellet beam pipe 6 mm diameter

  15. The microvertex detector • Baseline requirements : • vertex spatial resolution ~100 mm (charm vertices) • low material thickness to avoid MCS and conversions • forward angular coverage since PANDA is fixed target • radiation hardness technology

  16. barrel innermost 3 layers, pixels 50x400 mm2 beam mm pellet target pipe : 6 mm present design : barrel geometry with 5 layers. First 3 layers: pixel 400x50 mm2 , 2 outer layers : double sided strips are forseen to reduce material 5 forward wheels, pixel dimensions : 150x50 mm2, 2 outer layers : double sided strips to reduce material barrel forward disk The microvertex detector ~ 7.2 million pixels in barrel ~ 2 million pixel forward disks

  17. The microvertex detector Pixel technology Hybrid technology used in LHC, pixel total thickness : 250mm (sensor)+200mm(frontend)= 450 mm digitization performed locally with time over threshold method (as in Atlas) Forseen 0.13 mm technology for readout chip probably standard of the near future: smaller chips and lower power consumption than 0.25 mm technology Under investigation option 100x100 mm2 pixel detector

  18. beam The PANDA detector : central tracker, straw tube option 11 double-layers of 150 cm long straw drift tubes. First and last double-layers parallel to beam axis, remaining arranget at skew angles from 2° to 3° allowing z position measurement at 1cm precision. Left-right ambiguity resolution thanks to double and staggered layers. Also charge division for measuring position along beam axis. outer radius 42 cm Ar-CO2 mixture with gas gain ~ 105 for long operation time Expected x and y resolution : 150 mm inner radius 15 cm typical momentum resolution for particles between 2 and 8 GeV/c in relevant physics channels : 1% Prototype straws Straw diameter : from 4mm innermost to 8 mm outermost wire diameter : 20mm , wall thickness : 30 mm ~ 9000 straws

  19. The PANDA detector : central tracker, TPC option more challenging : collection of charge in ungated mode and tracks of different events E field along beam axis inner radius : 15 cm outer radius : 42 cm length : 150 cm gas volume : 700 liters typical momentum resolution for particles between 2 and 8 GeV/c in relevant physics channels : (0.5 – 2 )% Gas Electron Multiplier detectors for charge readout at the end caps : new solution from CERN

  20. detector planes arranged in staggered pairs to resolve left/right ambiguity The PANDA detector : multiwire drift chambers high flux rates expected near beam pipe : 3x104cm-2s-1,needed detector resistent to ageing minimal detector material : X0~ 1% 2 stations inside solenoid to track particles below 22° placed 1.4 and 2. m downstram target. Octagonal frames Dc1 and Dc2 option under study: cathod foil drift chambers expected resolution of MDC system for 3 GeV/c protons : dp/p = 0.2 % 6 stations forward, 2 before dipole 2 inside dipole, 2 downstream dipole Coverage of very high forward momentum tracks and low momentum spiralizing forward MDC inside dipole or downstream it, is made of 3 pairs of detection planes vertical, +45° , -45° rectangular shape to match dipole symmetry forward MDC before dipole is made of 4 pairs of detection planes vertical, +45° , -45°, horizontal octagonal shape to match solenoid azimuthal symmetry

  21. Charged particle identification for angles > 22° : the Dirc Charged particle ID essential in PANDA . Achieved with DIRC, RICH, dE/dx , ToF The DIRC for angles > 22° Measure Cerenkov cone  calculate angle of emission of Cerenkov light measure b of the particle Fused silica with n= 1.47 will allow K identification starting at 460 MeV/c PMT option : read out by 7000 PMT located outside magnetic field, with ultrapurified water as optical coupling APD option : read out by APD’s (Geiger mode) just outside the quartz bars R&D in progress for self-quenching Geiger mode APD’s quartz bar cross section : 17 mm x 30 mm Alternative option : measure precisely time of arrival of light instead of Cerenkov cone reduce PMT’s down to 120 They should be placed in contact with silica bars  work in high B field  use microchannel PMT’s already available (25 mm microchannel) ACTIVE R&D in progress

  22. Charged particle identification for angles < 22° : the forward Dirc and the Rich RICH, located downstream of dipole angle coverage < 10° forward Dirc : fused silica disk (or proximity imaging RICH) angle coverage between 10° and 22° Forward DIRC present design ideas : fused silica (n= 1.47) read out by 2304 pixels 10mm x 5° + 864 pixels 10mm x 10° lower momentum p/K separation ~ 1 GeV/c upper momentum p/K separation : 10 GeV/c at q =0 , 5 GeV/c at q = 25° RICH present design ideas : 3rd generation aerogel, hydrophobic, > 80% transmittance and no Hermes ‘meniscus’ difect read out : new type of multipixel hybrid photocatode GaAsP photocatode (60% q.e. in 300-700 nm range) multipixel avalanche diode, 64 pixels 2mm x 2mm, with < 100 ps time resolution in 1.5 T field

  23. Charged particle identification :dE/dx, ToF dE/dx measurements to separate p/K/p typically below 800 MeV/c If TPC will be implemented, it will be ideal device but also Straw Tubes since working in proportional mode and the MicroVertex Detecor pixels can measure dE/dx Time of Flight in the Target Region A cylindrical Time of Flight scintillation counter is placed around the DIRC 96 strips of fast scintillator like BC404 : decay constant 1.8 ns thickness 0.5 cm mechanically mounted together with DIRC phototubes : channel plate photomultipliers, can work up to 2.2 Tesla field p/K separation at 3 s level up to 430 MeV/c at q = 90° and up to 760 MeV/c at q = 22° Gianluigi Boca, Rio de Janeiro, Brazil, 21-26 Aug 2005

  24. the ToF wall in the forward region particle identification with momentum < 5 GeV/c distance ToF wall from target : 7 m; 5.6 m wide, 1.4 m tall 60 vertical strips of scintillator 5-10 cm wide side ToF wall inside dipole 5 vertical strips 10 cm wide, 1 m long Simulations show that with the help of the tracking system, a time resolution of 50 ps can be achieved for this ToF system Gianluigi Boca, Rio de Janeiro, Brazil, 21-26 Aug 2005

  25. The PANDA detector : m identification system muon system only for pattern recognition momentum measured in MVD Coverage up to 60° Scintillator counters : 96 strips 10 cm wide 200 cm long, 1 cm thick Mini Drift Tube counters : stations of double layer of 4 or 6 drift tube planes scintillator counters MDT

  26. The PANDA detector : the EM calorimeters EM calorimeter located in three positions : central barrel end caps forward Requiredfast, high resolution, radiation hard scintillator for  between 20 MeV - 4 GeV Presently favored solution : PbWO4 (PWO) crystals 22 cm2 22 X0 read out by APD’s used for the presence of strong magnetic field. Expected resolutions of < 2%/√E + 1% Central Barrel Barrel : 2.5 m long, 0.54 m radius, 11360 crystals downstream end cap : 1 m radius, 6864 crystals upstream end cap : 0.34 m radius, 816 crystals, segmentation in 16 slices

  27. s ± ( E ) ( 2 . 74 0 . 05 )% = ±  ( 1 . 96 0 . 1 )% [ ] E E GeV The PANDA detector : the EM calorimeters the end caps Forward : Shashlyk modules composed of lead absorbers and scintillators

  28. The forward hadronic calorimeter Detect neutrons, KL and to trigger on forward hadronic showers Filter for muon counters. Located 8 m downstream the target Plan to refurbish and use the calorimeter MIRAC from WA80 20 + 20 modules arranged in 2 rows Each module contains 100 layers steel-scintillator, 1.12 m long for a total 4.8 absorption lengths. Including phototubes and light guides is 170 cm long. Read out with WLS fibers into phototubes PANDA arrangment beam direction MIRAC calorimeter Geant 4 simulation shows resolution s/E = 0.40/√E

  29. Physics topics in more detail

  30. Excellent resolution of mass and width of all states driven by resolution on • p beam momentum and not by detector performances Charmonium physics 1 Charmonium masses and widths below and above the open charm threshold are predicted by non-relativistic potential models + relativistic corrections 2 In a p p experiment like PANDA ALL cc states can be formed and not just 1-- (as in e+e-experiments) CBall E835 100 cc1 1000 CBall ev./2 MeV E 835 ev./pb ECM 3500 3510 3520 MeV

  31. Charmonium physics below the DD threshold : the hcissue Discovery of hc by Belle in Bpc(KKp) confirmed by BaBar, Cleo Belle PDG 2005 : M(c) = 3638  5MeV G =14 ±7 MeV Disagreement of experiments on the mass and with early findings by Crystal Ball. Only marginal consistency with most theoretical predictions. Width measured only at 50 % precision. New high statistic measurement needed to settle the question

  32. Charmonium physics below the DD threshold : the hcissue Poor agreement among experiments on the mass and the width of the state. Width measured only at 10 % precision New high statistic measurement needed to settle the matter The radiative decays of the cJ Radiative decays like cJ J/ g and cJ gg are described by a dominating dipole term and multipoles arising from relativistic treatment of interaction between charmonium and electromagnetic field.This can be checked measuring the angular distributions of the c0c1 and c2radiative decays

  33. Charmonium physics below the DD threshold : the hc issue This singlet P resonance is very important in determining the spin dependent components of the the qq confinement potential . Two recent results presented at conferences and an early E760 result. Agreement on the mass at the 8.5 % level. New high statistic measurement needed ! pp hc c M=3525.80.2±0.2 MeV/c2 C. Patrignani, BEACH04 presentation E835 Cleo M(hc)=3524.40.9MeV/c2 e+e-0hc hcc hc c chadrons A. Tomaradze, QWG04 presentation E760 : M(hc)=3526.280.18±0.19 MeV/c2 In hcJ/p0 (1992)

  34. Charmonium physics above the DD threshold : the X discovery Belle Discovery of X(3872) by Belle (2003) B K X(3872) (and XJ/p+p-) confirmed by CDF(2004), D0(2004), BaBar (2005) • What is the X(3872) ? • Charmonium 13D2 or 13D3. • D0D0* molecule. • Charmonium hybrid (ccg). PDG 2005 M=3871.70.6MeV/c2 2.3MeV(90%C.L.) Good agreement on X mass of the 4 experiments

  35. Charmonium physics above the DD threshold Above DD threshold charmonium spectrum poorly know with measures of R in large steps Structures at 4040, 4160 and 4415 need confirmation relatively narrow states expected by potential model

  36. What PANDA can do for charmonium physics • 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).

  37. Gluonic excitations (hybrids, glueballs) and other exotics • QCD allows for richer spectrum than quark model because gluons • can became principal components of new hadrons : glueballs and • hybrids. Additional gluons allow to have an exotic Jpc forbidden for • regular hadrons. Their properties are determined by the long • distance features of QCD  studying them is fundamental !! • Also hadrons with more than qq or 3 quarks are expected to exist. • Hybryds : qqg • Glueballs : states of pure glue • Oddballs : states of pure glue with exotic quantum numbers: • ( 0 -- , 0+ - , 1- + , 2 + -etc.) • Other exotics : tetraquarks, pentaquarks. • Exotic JPC will be a powerful signature for experimental detection. • LQCD calculations improved precision along the years in prediction • of masses and widths of these states. _

  38. overlap with few narrow states -- -+ 1 1 cg 2 10 qg c q c i t t o h x g i E l c i 1 t o x E -2 10 4000 0 2000 MeV/ c 2 Gluonic excitations non-charmonium hybrids overlap with many broad states potential and wavefunctions energy levels excited glue charmonium hybrids excited glue K. Juge, J. Kuti, C. Morningstar PRL 90 (2003) 161601 see also K.Juge talk at this conference, parallel session on Thursday 1-g exchange

  39. 0+- 2+- Glueball color blindness : can dacay in uu, dd, ss and cc Morningstar,Peardon, PRD60(1999)34509 Morningstar,Peardon, PRD56(1997)4043 Gluonic excitations : glueballs and oddballs Investigation of glueballs is essential to understand long-distance QCD. LQCD predicts 15 glueball states with mass accessible to PANDA, some with exotic quantum numbers (oddballs). exotic Predicted width ~ 100 MeV Glueballs can mix with normal hadronic resonances in same mass range while oddballs, due to exotic JPC are predicted to be narrower and easier to find in partial wave analysis Glueballs decays most favourable to PANDA are fforfhif mass < 3.6 GeV/c2 or to J/h or J/ fabove 3.6 GeV/c2 First oddball 2+-predicted at 4.3 GeV/c2 very well in the reach of PANDA in formation or production. • PANDA can form and produce glueballs (oddbals) : • ppff statistics 2 orders of magnitude better than • Jetset at LEAR • also measure pp ww , rr, KK* • study of h(1475)KKp seen by Obelix at LEAR

  40. Theq+(1540) decaying into pKsor nK+ has been seen by 10 experiments. The weighted average of the mass is 1533.6 ± 1.2 MeV/c2 but unfortunately compatibility of 10 measurements is only 1.6x10-5 Pentaquark with strange content decaying into  p with Mass = 1862±2 MeV/c2 and G < 18 MeV/c2 claimed by NA49 in 2004 Other exotics : tetraquarks, pentaquarks Recent hints of pentaquarks qqqqq discoveries have been claimed Pentaquarks with charm content decaying into D* p with Mass = 3099±3±5MeV/c2and G =12 ±3 MeV/c2 claimed by H1 in 2004 PANDA can access to pentaquarks and tetraquarks (qqqq) up to ~ 2700MeV/c2 The p p q+q- reaction could be studied near threshold

  41. p- 25 MeV p p+ K+ K 100 MeV K- D • study of nuclear bound states with slow K- or L produced inside nuclei • study of mass shifts of charmonium states, produced in nuclei and decaying into leptons or g • study of production yield of DD pairs produced below threshold in nuclei. Increase of cross • section due to increased phase space • dependence of all above on nucleus size • study of the possible effect of the opening, in nuclei, of the DD decay channel to states normally • below threshold like (3770), , c2 D- 50 MeV D+ Hayaski, PLB 487 (2000) 96 Morath, Lee, Weise, priv. Comm. Hadrons in nuclear matter vacuum nuclear medium Mass shifts caused by potential in nuclear matter r, w, f : substantial shifts predicted. Experimental goal of HADES at GSI cc mesons sensitive only to gluon condensate in nuclei due to heavy c mass  predicted only 5-10 MeV mass reduction for J/ and hc but 40 MeV for cJ,100 MeV for  and 140 MeV for (3770) Calculation: A. Sibirtsev et al., Eur. Phys. J A6 (1999) 351 D-Mesons: theoretical predictions on size of mass splitting depending on the model. Important to measure experimentally high intensity p beam up to 15 GeV/c opens up the possibility of :

  42. t ~ 10…20 fm/c final state = e+e- / m+m- / gg / J/yg  _  p  t 10 fm/c (collisional broadening) ~ 1 fm Hadrons in nuclear matter, physics reach in PANDA Predicted rates at L = 1032 cm-2s-1: few 10 … few 100 events/day S.H. Lee, nucl-th/0310080

  43. _ p + A  J/y + (A-1) ; detect J/y m+m- (e+e-)  J/y absorption cross section in nuclear matter, scarce experimental data  can be used later by experiments that study J/y suppression as signal for Quark Gluon Plasma J/  absorption in nuclear matter

  44. Hypernuclear physics In hypenuclei one (or more) L substitute one (or more) nucleon. A whole new set of states can exist containing an extra degree of freedom : strangeness. The lighter single strangeness ( L-hypernuclei ) energy levels are predicted in the frame of the shell model, where the L particle is subject to an effective single particle potential. Heavier L-hypernuclei and LL-hypernuclei are described by more complicated models. Experimental situation : ~35 L-hypernuclei established since 50 years ago Only 6 LL-hypernuclei

  45. produce X- X at threshold in pp  X-X use a secondary target whereX- is captured in a hyperatom and then interacts in nucleus X- + AZ  A+1LL(Z-1)* A+1LL(Z-1) +g(’s)detected in apparatus A+1(Z+1) + p-p- detectg with high resolution germanium detector in coincidence with tag. A+1LL(Z-1) subequently decays via pionic cascade into normal nucleus. X LL-hypernuclei production and detection in PANDA p Tag hypernucleus pionic decay _ 2.6 GeV/c X- ground state LL hyp.nucl. excited LL-hyp.nucl. X ray secondary target normal nucleus p detected g(‘s) detected in apparatus X-(dss)p(uud)→L(uds)L(uds) p detected

  46. Hypernuclei physics : detector requirements Current state of the art g detection resolution : 2 KeV (KEK E419) Current state of the art p detection resolution : D E = 1.29 MeV Finuda Collaboration, PLB622: 35-44, 2005 Solid state detector (diamond or silicon) compact : thickness ~ 3 cm high rate capability high resolution capillar (2D) or pixel (3D) position sensitive Germanium g detector (like Vega or Agata)

  47. spA(XX) = A2/3spp(XX) spp(XX) = 2 mb @ 3 GeV/c joint XX escape probability : 5x10-4 (trigger on X and 100 < PX- < 500 MeV/c) X reconstruction efficiency : ~ 50 % X- stopping and capture probability :~ 20 % ~ 3x103 captured X-/day X-p LL conversion probability : 5% ~ 150 LL-hypernuclei /day g emission probability: 50% g Ge photopeak efficiency : 10% ~ 7 golden events/day K+K+ trigger ~ 700 events /day Hypernuclei physics : expected rates in PANDA using a 12C wire as primary target at L = 2 x1032cm-2 s-1 PANDA will produce ~7x102XX/ sec

  48. PANDA as an open charm factory Running at full luminosity of 2x107, above the 3.73 GeV open charm threshold or at the (3770), assuming s(ppDD) ~ 1 mb, with 50 % reconstruction efficiency in the D golden modes from MC calculations, and 107 s running time in a year, PANDA will detect ~ 109/year DD golden mode pairs per year in a SUPER CLEAN almostbackgroundless type of event. PANDA will be the mecca for all those who want to do the D mesons charm physics. The only forseeable next generation charm factory, with possibly 103 times today’s BaBar charm yields. It will continue the very successful program in charm physics of experiments like Cleo, Focus, BaBar, Belle.

  49. PANDA as an open charm factory Possibility of studying a large part of the physics issues concerning charm physics : direct CP violation T-violation mixing in the D0D0 system rare and forbidden decays D+ l+n semileptonic decay and form factors Dalitz plots relative and ABSOLUTE branching ratios singly and doubly Cabibbo forbidden decays multihadronic decays new D decays

  50. pp  g g Lately a new approach applied the same formalism to ppg e+ e- ppg m+m- pp g + vector meson (r, f, w) Crossed-channel Compton scattering and related exclusive processes Recently shown this reaction can be described in terms of GeneralizedPartonDistributions Using a hand bag diagram the process separates into a soft part parametrized byGPDsand ahard part described by a quasi-free qq scattering into gg The production of a hard di-lepton pair is a hard subprocess that is assumed to factorize from the lower part that is described by a hadron to g transition amplitude

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