J. RitmanForschungszentrum Juelich The PANDA Experiment: Exploring the Emergence of Structure in Matter

Jim Ritman 2 Hadron Physics with PANDA QCD well understood at high Q 2 Emergence of eff. DoF at low Q 2 Study of the strong interaction in the transition region Phenomena appear that are hard to predict from QCD: e.g. confinement, nature of hadrons, hadronic masses… J. Pumplin et al., JHEP 0207 (2002) 012

Jim Ritman 3 How Do We Study the Hadrons? Hadron Structure: Hard (virtual) photons, typically accessed via leptons, allow us to measure the constituents - Generalized parton distribution - Drell-Yan processes - Time-like form factor of the proton Hadron Spectroscopy: Excitation spectrum accesses rare quark/gluon configurations - Search for glueballs, hybrids, molecules, tetraquarks … - Baryon spectroscopy - In-medium effects Hadron Interactions: Pion/Kaon reactions, as well as Hyperons and Hypernuclei provide information about the strong force - Double hypernuclei

Jim Ritman 4 Hadron Structure with Electromagnetic Probes

Jim Ritman 5 Time-Like & Space-Like EM Form Factors Constraints: G E p (0)=1 G M p (0)=μ p G E p (4m p ²)= G M p (4m p ²) Asymptotics |G E,M (q²)| ~ (q²) - ² (Phragmén-Lindelhöf theorem) Imaginary part of Time-Like form factors vanishes for q² → + ∞ Time-like _ _ q 2 <0 e-e- e-e- pp q 2 >0 e-e- p q2q2 Complex FFs Real FFs Unphysical region Space-like p+p ↔ e + +e - e+p  e+p p+p  e + +e - + X SL TL 3.52 (GeV/c) 2 p 0 e+e+

Jim Ritman 6 e - scattering ( Jlab…. A2/Mainz) e + e -  pp (BES, Novosibirsk, PANDA) unphysical G M /μ p p Spacelike Timelike From S. Pacetti, arXiv: v1 q 2 > 4m p 2 annihilation pp  e + e - electron scattering q 2 < 0 Time - Like& Space-Like EM Form Factors Dispersion relations: 20 -

Jim Ritman 7 4m p 2 angular distributions: pp → e + e - _ Proton EM Form Factors in Time-Like Region G eff - - G eff : large error bars above 13 (GeV/c) 2 |G E /G M | :  Inconsistent data above threshold  Lack of precise data above 5 (GeV/c) 2 Cross-sections: pp → e + e - _ LEAR (pp) E835 BABAR: (e + e -  pp  ) (pp) - FENICE+DM2 (e + e - ) -

Jim Ritman 8 Goal of PANDA Measurements Two major challenges: Decrease of sensitivity to G E with increasing q 2 Huge hadronic background  (pp  +  - ) /  (pp  e + e - ) ~ Extract Time-Like |G E | and |G M | for proton up to 14 (GeV/c) 2 from lepton angular distributions in pp  e + e - reaction and measure G eff up to 30 (GeV/c) 2 - -

Jim Ritman 9 Counting Rate and Sensitivity to |G E | N tot = N tot =64000 N tot =2000 ~120 days, L = 2x10 32 cm -2 s -1 L int = 2 fb -1 G E =0 G E =G M G E =3G M Statistical errors only M. Sudol et al. EPJA 44 (2010) 373

Jim Ritman 10 parametrization of CERN data for p p →  +  - s < 6 (GeV/c) 2 : Legendre polynomial fits s > 6 (GeV/c) 2 : counting rules (Ong et Van de Wiele, IPNO-DR-08-01) or Regge trajectories (idem, EPJA46 (2010) 291). Rejection of pp   +  - Background cos  CM q 2 = 8.21 (GeV/c) 2      (e + e - ) _ ?      (e + e - ) pp  π + π New measurements of p p →  +  - will be provided by PANDA (also important for pQCD mechanism studies)

Jim Ritman 11 E. Tomasi-Gustafsson and M.P. Rekalo, PLB504,291 E. Tomasi-Gustafsson, arXIv: Courtesy of S. Pacetti PANDA Phragmèn-Lindelöf theorem ? Time-Like Form Factor Measurement with PANDA : Estimates of Precision Sudol et al. EPJA 44 (2010) 373 < 1% ~10% ~23% ~50% G eff PANDA pQCD ? L =2 fb -1 BES

Jim Ritman 12 Sudol et al. EPJA 44 (2010) 373 < 1% ~10% ~23% ~50% G eff PANDA pQCD ? L=2 fb -1 -VDM: F. Iachello et al., PLB43, 171 (1973) …extended VDM, PRC66, (2002) Egle Tomasi-Gustafsson et al., EPJA24 (2005) 419 PANDA will bring Precise determination of |G E | and | G M | up to 14 (GeV/c) 2 G eff up to 30 (GeV/c) 2 : transition towards perturbative QCD PANDA BES Time-Like Form Factor Measurement with PANDA : Estimates of Precision

Jim Ritman 13 2  Contributions and Radiative Corrections ? Polarization measurements Rosenbluth method Important role of 2  exchange and radiative corrections Advantage of annihilation reactions pp  e + e - The e + and e - angular distributions are measured in the same experiment PANDA measurements are sensitive to odd cos  terms d  /dcos  e ~ A (1+ b cos  e sin 2  e + c cos 2  e +..) with b=5% or more (M. Sudol et al EPJA 44(2010) 373). _ No C-odd terms contribution C-odd terms contribution

Jim Ritman 14 Hadron Spectroscopy with Antiproton Annihilation

Jim Ritman 15 Why Antiprotons?  difficult to make BUT:  gluon rich process  gain ~2 GeV in annihilation, reduced momentum transfer  all fermion-antifermion quantum numbers accessible  very high resolution in formation reactions  high angular momentum accessible

Jim Ritman 16 Particle production in pp collisions Formation: _ All J PC allowed for (qq) accessible in pp __ Only J PC = 1 -- allowed in e + e - (to 1st order) c.f.

Jim Ritman 17 Invariant mass reconstruction depends on the detector resolution ≈ 10 MeV Example: χ c1,2 Formation: Resonance scan: Resolution depends on the beam resolution ≈ 240 keVPANDA ≈ 30 keV

Jim Ritman 18 Charmonium Spectroscopy open questions below DD threshold: widths, branching new „XYZ“ states (Belle, BaBar, CLEO, CDF, D0, …) new degrees of freedom: molecules, tetraquarks, gluonic excitations? conventional states above DD high L states: access in pp but not in e + e - _ _ _

Jim Ritman 19 New Charmonium-like Discoveries X(3872) PRL 91, (2003) X(3940) PRL 98, (2007) Y(3940) PRL 94, (2005) X(3915) PRL 104, (2010) Y(4260) PRL 95, (2005) Y(4350) PRL 98, (2007) Y(4008) PRL 99, (2007) Y(4660) PRL 99, (2007) Z(4430) - PRL 100, (2008) Z 1 - & Z 2 - PRD 78, (2008) Y(4140) PRL 102, (2009) X(4350) PRL 104, (2010) in addition to many more open charm states

Jim Ritman 20 How can PANDA contribute? simulation studies for several channels and √s : J/ψπ + π -, J/ψπ 0 π 0, χ c γ  J/ψ γγ, J/ψ γ, J/ψ η, η c γ direct formation in pp: line shapes ! d target: pn with p spectator tagging, e.g. Z - (4430) ≈ 100 events/day ≈ 40 events/day S/N =25 ε = 32 % S/N = 2 _ _ C. Hanhart et al., PRD 76 (2007) J/     D 0 D *0 _ J/     D 0 D *0 _ E. Braaten, M. Lu, PRD 77 (2008) D0D00D0D00 _

Jim Ritman 21 Beyond standard quark configurations QCD allows much more than what we have observed: BaryonsMesons Courtesy C. Hanhart Exotics: may have J PC not allowed for qq _

Jim Ritman 22 Exotics production in pp collisions Production: all J PC accessible G.Bali, EPJA 1 (2004) 1 (PS) _ Hybrids J PC exotic Exotic J PC would be clear signal

Jim Ritman 23 Open charm: The D s spectrum B. Aubert et al. (BaBar Collab.), Phys. Rev. D 74 (2006) D. Besson et al., Phys. Rev. D68, (2003) B. Aubert et al., Phys. Rev. Lett. 90, (2003) new narrow states D s * (2317) and D s * (2460) seen by BaBar, Belle, CLEO masses significantly lower than quark model expectation states are just below DK and D * K threshold interpretation unclear: DK / D * K molecules, tetraquarks, chiral doublers, …?

Jim Ritman 24 D s0 * (2317) Theoretical Predictions Approach  (D s0 *(2317)  D s  0 ) (keV) M. Nielsen, Phys. Lett. B 634, 35 (2006) 6  2 P. Colangelo and F. De Fazio, Phys. Lett. B 570, 180 (2003) 7  1 S. Godfrey, Phys. Lett. B 568, 254 (2003) 10 Fayyazuddin and Riazuddin, Phys. Rev. D 69, (2004) 16 W. A. Bardeen, E. J. Eichten and C. T. Hill, Phys. Rev. D 68, (2003) 21.5 J. Lu, X. L. Chen, W. Z. Deng and S. L. Zhu, Phys. Rev. D 73, (2006) 32 W. Wei, P. Z. Huang and S. L. Zhu, Phys. Rev. D 73, (2006) 39  5 S. Ishida, M. Ishida, T. Komada, T. Maeda, M. Oda, K. Yamada and I. Yamauchi, AIP Conf. Proc. 717, 716 (2004) H. Y. Cheng and W. S. Hou, Phys. Lett. B 566, 193 (2003) A. Faessler, T. Gutsche, V.E. Lyubovitskij, Y.L. Ma, Phys. Rev. D 76 (2007)  32.6 Y. I. Azimov and K. Goeke, Eur. Phys. J. A 21, 501 (2004) 129  43 (109  16) M.F.M. Lutz, M. Soyeaur, arXiv: [hep-ph] 140 Feng-Kun Guo, Christoph Hanhart, Siegfried Krewald, Ulf-G. Meißner Phys Lett. B 666 (2008)  40  100

Jim Ritman 25 Method: Threshold Scan reaction: excitation function only depends on m and Γ of D s (2317) experimental accuracy determined by beam quality (Δp, σ p /p), not by detector resolution

Jim Ritman 26 Simulation Results: Energy Scan M sum = M miss (D s ) + M(D s )  = 100 keV

Jim Ritman 27 Hadron Interactions: Double Strange Hypernuclei

Jim Ritman 28 Production Mechanism and Detection Strategy

Jim Ritman 29 Instrumentation

Jim Ritman 30 The PANDA Collaboration 517 Members from 67 Institutes 18 Countries Australia, Austria, Belarus, China, France, Germany, India, Italy, Poland, Romania, Russia, Spain, Sweden, Switzerland, Thailand, The Netherlands, USA, UK