Experiments with a cooled p beam on an internal target

1. High Energy Storage Ring HESR p Pmax = 1.5-15 GeV/c Lmax = 2·1032 cm-2 s-1 Ø < 100 μm Δ p/p = 10-4 …10-5 e- cooler detector Experiments with a cooled p beam on an internal target • Physics program • Detector set-up

2. Charmonium spectroscopy Medium modifications of D mesons and J/Ψ in nuclei Hypernuclei Glueballs Hybrids CP violation Physics program

3. Charmonium spectroscopy • Charmonium gives information about QCD confinement potential. • Many states are still missing. • pp: direct formation of all states. • HESR allows investigation of states above DD threshold. • Cooled beams with Δp/p=10-4…10-5 allow high precision scan of resonances. Crystal Ball e+e- 40 keV

4. Charmonium spectroscopy Crystal Ball e+e-

5. Signal: exotic quantum numbers: partial wave analysis normal quantum numbers: model comparison (LGT) Glueballs Hybrids mixing with normal mesons charm sector: few resonances with small widths Meson Hybrid Glueball ggg qq qqg Normal meson: 2 fermions P = (-1)L+1 C = (-1)L+S Excited glue: bosonic degree of freedom → exotic quantum numbers eg. JPC=1-+, 0--, 0+-, 2+-… → normal quantum numbers

6. Glueballs Hybrids

7. Mass modifications of mesons pionic atoms π- 25 MeV π π+ KAOS/FOPI K+ K 100 MeV K- HESR D D- 50 MeV ? D+ vacuum nuclear medium ρ = ρ0 Medium modifications of D mesons and J/Ψ in nuclei Continuation of present GSI physics FOPI, KAOS, HADES, …HESR Signal: medium modification of production threshold, resonance width e.g. Ψ’, χ2 Absorption cross section of J/Ψ in nuclei (ρ=ρ0).

8. _ X 3 GeV/c p X- Hypernuclei K+K Trigger • X-(dss)p(uud)L(uds)L(uds) • study of L L interaction secondary target

9. Measure decay asymmetry of angular distribution of p relative to Λ-Hyperon momentum. Ip(θp) ~ 1+α cos(θp) for Λ Ip(θp) ~ 1+α cos(θp) for Λ CP conservation: α = - α Signal for CP violation: Theoretical prediction: Experiment: 1010 reconstructed ΛΛ L=2·1032 cm-2 s-1 → >1 year running p + p → Λ +Λ ↓ ↓ pπ- pπ+ CP violation in Hyperon decay

10. HESR-Detector Simulations Formation of Ψ’and decay in myons electrons similar → calorimeter for large angles. Ψ’→μ+μ- Ψ’→J/Ψ + X ↓ μ+μ-

11. HESR-detector target spectrometer forward spectrometer Internal target top view Heavy charmed mesons decay in light products with large pt. Solenoid is important.

12. side view HESR detector

13. Costs

14. Interest: LEAR, COSY, SATURNE community Munich Germany Bochum “ Giessen “ Dresden “ Erlangen “ Jülich “ Ferrara Italy Turin “ Krakow Poland Warsaw “ Evanston USA

17. 2 mio. forward pixels 100 x 150 μm 7.2 mio. barrel pixels 50 x 300 μm beam pipe pellet pipe Microvertex Detector

18. Detection of internally reflected Č-light (DIRC)