Antiproton Requirements for Klaus Peters KPIII/HPI, GSI Darmstadt IKF, JWGU Frankfurt p-Workshop, GSI, Darmstadt Dec 3, 2007

2 Klaus Peters - pbar Requirements for HESR PANDA Conventional and exotic charmonium spectroscopy Formation (scans) Production (with recoil) Nucleon structure issues Electromagnetic form factors Cross channel Compton scattering Drell-Yan and others Hyper nuclear physics Flavored baryons Many other topics

3 Klaus Peters - pbar Requirements for Panda Detector High Rates Total σ ~ 55 mb peak >2·10 7 int/s Elm. Calorimetry (γ,π 0,η) Magnetic tracking Forward capabilities (leading particles) Sophisticated Trigger(s) Vertexing (σ p,K S,Λ,…) Charged Particle ID (e ±,μ ±,π ±,p,…)

4 Klaus Peters - pbar Requirements for Panda Quark-Antiquark Binding  Charmonium Physics D DD*DD* ψ(1 1 D 2 ) ψ(1 3 D 2 ) ψ(1 3 D 3 ) ψ(1 3 D 1 ) M cc [GeV/c 2 ] η c (1 1 S 0 ) η c (2 1 S 0 ) J/ψ(1 3 S 1 ) χ c0 (1 3 P 0 ) χ c1 (1 3 P 1 ) χ c2 (1 3 P 2 ) h 1c (1 1 P 1 ) D*D* ψ(3 3 S 1 ) p p [GeV/c] ψ(2 3 S 1 ) χ c0 (2 3 P 0 ) χ c1 (2 3 P 1 ) χ c2 (2 3 P 2 ) h 1c (2 1 P 1 ) η c (3 1 S 0 ) J P = (0,1,2) (1,2,3) - But many recent findings don‘t fit very well

5 Klaus Peters - pbar Requirements for Panda The Potential – A Guide spin-orbit (fine structure) spin-spin (hyperfine structure) tensor V S and V V are the scalar and vector components of the non-relativistic potential R/r 0 V( R )/GeV J/ψ χcχc ψ‘ψ‘ HccHcc D Π Σ G. Bali et al., hep-lat/ G. Bali, hep-ph/

6 Klaus Peters - pbar Requirements for Panda Z + (4433) arXiv:

7 Klaus Peters - pbar Requirements for Panda X(3872) and Confirmation hep-ex/ σ 11.6 σ BABAR Phys. Rev. Lett. 91(2003) Mill. BB

8 Klaus Peters - pbar Requirements for Panda Mass Differences in ψππ and DDπ X(3872) in (ψππ) K + Bellem=3872±0.6±0.5 Babar m=3871.3±0.6±0.1 X(3872) in (ψππ) K S Bellem=3871.8±1.1±0.6 Babarm=3868.6±1.2±1.2 Γ<2.3 X(3872) in DDπ K Bellem=3875.4± Babarm= ±0.5 Γ= ±0.9 m D0D0* =3871.8±0.3 m D+D-* =3879.9±0.3 E. Braaten, only D 0 D 0* threshold considered about 3 MeV between final states

9 Klaus Peters - pbar Requirements for Panda Mass and Width Determination D sJ (*) (2xxx) Deduce mass and width from excitation function Many channels, but all require e-cooling at large energies threshold D s0 *D s0 *threshold D s D s0 * possible experimental result

10 Klaus Peters - pbar Requirements for Panda Experimental Questions - Charmonium Do Charmonium hybrids exist? Like 1 -+ (expected to be the lightest spin-exotic state) Are there J PC exotics in Charmonium? Some observed states are extremely narrow… Like X(3872), D sJ * (2317), D sJ (2459), … What is the real width? Some are observed near thresholds Like X(3872) (DD*), Y(4260) (D s D sJ * ), … What is the line shape, dispersive/coupled channel effects? There is one charged candidate– multiquark candidate Z + (4433) Are there neutral partners? Are there more? What is the line shape? Is it a real resonance?

11 Klaus Peters - pbar Requirements for Panda Experimental techniques - Charmonium Do Charmonium hybrids exist? Like 1 -+ (expected to be the lightest spin-exotic state) Are there J PC exotics in Charmonium? Some observed states are extremely narrow… Like X(3872), D sJ * (2317), D sJ (2459), … What is the real width? Some are observed near thresholds Like X(3872) (DD*), Y(4260) (D s D sJ * ), … What is the line shape, dispersive/coupled channel effects? There is one charged candidate – multiquark candidate Z + (4433) Are there neutral partners? Are there more? What is the line shape? Is it a real resonance? Charmonium production w/ light recoil particles [large p p (15 GeV/c)] Charmonium formation [Δp ~ keV] Charmonium production w/ light recoil threshold (e.g. Z + π - ) [p p >10 GeV/c, Δp ~ keV] Charmonium formation w/ anisotrop momentum steps

12 Klaus Peters - pbar Requirements for Panda pp cross sections PANDA Crystal BarrelE760/E835 Obelix PS185 Jetset CITATION: W.-M. Yao et al., J. Phys. G 33,1 (2006)

13 Klaus Peters - pbar Requirements for Panda pp cross sections – exclusive final states 100 mb 10 mb 1 mb 100 μ b 10 μ b 1 μ b 100 nb 10 nb 1 nb ΛΛ 3π03π0 ΞΞ ΩΩ Ξ*ΞΞ*Ξ Ω*ΩΩ*Ω Λ*cΛcΛ*cΛc drop of cross section due to disconnected quark lines s dependence σ~s -X for large phase space (e.g. 2π 0 σ~s χ cJ )

14 Klaus Peters - pbar Requirements for Panda pp cross sections – exclusive final states 100 mb 10 mb 1 mb 100 μ b 10 μ b 1 μ b 100 nb 10 nb 1 nb ηcηc χ c0 χ c2 ηcπ0ηcπ0 Hybrids Glueballs X (3872) Example X (3872) peak ~50 nb (E. Braaten) DDπ/ψππ ~10:1  ψππ 250 pb (ee and μμ)  DDπ 500 pb (multiple channels) includes eff. and BR L=2·10 31, duty ε=0.5 ∫ (L*ε) = 0.86 pb -1 /d  2 d/point  peak (~400 ev. ψππ/~800 ev. DDπ) x 20 points  40 days

15 Klaus Peters - pbar Requirements for Panda Experimental Method in pp Scans The cross section for the process: pp  cc  final state is given by the Breit-Wigner formula: The production rate ν is a convolution of the BW cross section and the beam energy distribution function f(E,ΔE): The resonance mass M R, total width Γ R and product of branching ratios into the initial and final state B in B out can be extracted by measuring the formation rate for that resonance as a function of the cm energy E.

16 Klaus Peters - pbar Requirements for Panda Exotic Charmonium Production Expected cross sections are O(1nb) typical channels involve DD or J/ψ  leptons BR lead to small yields O(1-few %) Reconstruction ε~10-40% L=2·10 32, duty ε=0.5 ∫ (L*ε) = 8.6 pb -1 /d Example η 1 η [1 nb]  χ c1 ππη  l + l - 7γ [10 pb incl. ε, multichannel l + l - /η] Goal: minimum 10k for PWA  116 d or 1 fb -1 Ideal: 50k  ~600 d or 5 fb -1 Strategy 1 p-year running (~200 d) at p p =15 GeV/c for a survey additional running at optimized * (slightly lower) momentum to improve PWA sensitivity (final goal: total ~600 d, 3 p-year) * ) depending on findings

17 Klaus Peters - pbar Requirements for Panda Hypernuclear Limiting factor charged particle load on central detector ( )·10 7 L=(3-5)·10 30 cm -2 s -1 p re-storage <6·10 6 Ξ-Ξ- Secondary Target 3 GeV/c Trigger K+K Carbon Wire ø 10 μm Ξ - (dss)p(uud)  Λ(uds)Λ(uds) # Neutrons # Protons Minium 8 months full running

18 Klaus Peters - pbar Requirements for Panda Crossed-channel Compton scattering Cross section σ ≈ 2.5 s≈10 GeV 2 L = 2·10 32 cm -2 s -1 → 10 3 Events/Month Electromagnetic form factor of the proton (time-like)

19 Klaus Peters - pbar Requirements for Panda p [GeV/c] √s [GeV/c 2 ] Physics3· · >1.4>2.23ΛΛ151 keV51 keV15 keV5 keV ~2~2.4Light Quarks ηcηc 336 keV112 keV34 keV11 keV X(3872)504 keV168 keV50 keV17 keV D s D s0 *(2317)574 keV192 keV58 keV19 keV Charm Production 755 keV252 keV77 keV25 keV Resolution for various various p p few 100 keV 100 keV keV 100 keV <1 MeV

20 Klaus Peters - pbar Requirements for Panda Resolution for various various p p x x GeV/c Δp/pLumi Lowest Δp/p required for charm-state scans Relaxed for detector resolution dominated cases Light Quarks Hyper- nuclei Narrow Charm Nucleon Structure Exotic Charm

21 Klaus Peters - pbar Requirements for Panda various p p x x GeV/c Δp/pLumi Light Quarks Hyper- nuclei Narrow Charm Nucleon Structure Exotic Charm Highest luminosity required for exotic charm discoveries and nucleon structure physics detector saturation

22 Klaus Peters - pbar Requirements for Panda Target considerations General for p in HESR (circ. 574 m) 2·10 32 require target thickness d LOI =3.8·10 15 H/cm 2 Cluster-Jet-Target achieved 1·10 15 (EU-FP6), final goal (realistic) (3-5) ·10 15 (EU-FP7) if 5·10 15 could be achieved the exp. p loss during the spill could be partly compensated Pellet-Target achieved 2·10 15 H/cm 2 main problems: pellet yield, luminosity variations (25 μm pellets, pellet has 6·10 19 H/cm 2 )

23 Klaus Peters - pbar Requirements for HESR PANDA Maximum beam 7-10 GeV/c should not exceed 3 · ideal 1 · to be safe at small and large momenta should not exceed 3 · · respectively 7-10 GeV/c (high prec. mode) minimum ideally ~2·10 31 at small momenta may be enough, but physics is limited then at large momenta minimum ideally >2 · to increase discovery potential and reasonable nucleon structure measurements Running time ≥200 d/year  Detector maintainance ~3 m/year