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Introduction. FAIR Facility Status of the PANDA Detector Brief Overview of the Physics Program (exotic) Charmonium (exotic) Open Charm Summary. Facility for Antiproton and Ion Research. SIS18. SIS100. p- Linac. HESR. Antiprotons Production Target. CR/RESR.
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Introduction • FAIR Facility • Status of the PANDA Detector • Brief Overview of the Physics Program • (exotic) Charmonium • (exotic) Open Charm • Summary
Facilityfor Antiproton and Ion Research SIS18 SIS100 p-Linac HESR Antiprotons Production Target CR/RESR
Facilityfor Antiproton and Ion Research Areal view July 27th, 2013
HESR with PANDA and Electron Cooler 1010 - 1011 Antiprotons stored Thick target 4·1015 cm-2 Δp/p ≤ 4·10-5 Lumi up to 2·1032 cm-2s-1 Phase space cooling beam life time: > 30 min COSY HESR
Electron Cooler, HESR Injection energies • HESR Injection energies (3.5 GeV/c) • 2 MV x 1 A • Installed in COSY in 2013
PANDA Detector Scenario • High background: exclusive event reconstruction essential simultaneous neutral and charged particles close to full 4p acceptance • Glueballs/Hybrids/etc.: high kaon yield PID over full forward hemisphere • Resonances/Molecular states/etc.: concurrent measurement of different decay branches MVD and EMC • Electromagnetic final states: e+/- and m+/- EMC and Muon Detectors
p Momentum [GeV/c] 0 2 4 6 8 10 12 15 ΛΛ ΣΣ ΞΞ ΩΩ DD ΛcΛc ΣcΣc ΞcΞc ΩcΩc DsDs qqqq ccqq nng,ssg ccg nng,ssg ccg ggg,gg ggg light qq π,ρ,ω,f2,K,K* cc J/ψ, ηc, χcJ 1 2 3 4 5 6 Mass [GeV/c2] PANDA Program • Meson spectroscopy • light mesons • charmonium • exotic states • glueballs • hybrids • molecules/multiquarks • open charm • Baryon/antibaryon production • Charm in nuclei • Strangeness physics • Hyperatoms • S = -2 nuclear system • Ξ− nuclei • ΛΛhyepernuclei • E.M. processes
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
c.f. Only JPC = 1-- allowed in e+e- (to 1st order) _ Particle production in pp collisions Formation: _ _ All JPC allowed for (qq) accessible in pp
High Mass/Width Resolution, e.g.: χc1,2 • Invariant mass reconstruction depends • on the detector resolution ≈ 10 MeV Formation: Resonance scan: Resolution depends on the beam resolution E760@Fermilab ≈ 240 keV PANDA ≈ 50 keV
Charmonium Spectroscopy _ • open questionsbelow DD thresholdwidths, branching • new „XYZ“ states (Belle, BaBar, CLEO, CDF, D0, LHCb…) • masses are poorly known; • often widths are just upper limits; • few final states have been studied; • statistics are poor; • quantum number assignment is possible for few states; • some resonances need confirmation… • newdegreesoffreedom: molecules, tetraquarks, gluonic excitations? • conventionalstatesabove DD • high Lstates: access in pp but not in e+e- _ _
New Charmonium-like Discoveries in addition: many new open charm states
_ Exotics production in pp collisions • Production: all JPC accessible Hybrids JPC exotic Exotic JPC would be clear signal G.Bali, EPJA 1 (2004) 1 (PS)
How can PANDA contribute? ε = 32 % S/N = 2 • simulation studies for several channels and √s: • J/ψπ+π-,J/ψπ0π0, χcγJ/ψγγ, J/ψγ, J/ψη, ηcγ • direct formation in pp: line shapes ! • d target: pn with p spectator tagging, e.g. Z-(4430) _ _ C. Hanhartet al., PRD 76 (2007) 034007 E. Braaten, M. Lu, PRD 77 (2008) 014029 J/yp+p- _ _ _ D0D*0 D0D*0 D0D0p0 ≈ 100 events/day ≈ 40 events/day S/N =25 Compare lineshapes in different final states! J/yp+p-
Open Charm: The DsSpectrum • Th./Expt. in qualitative agreement for D states, but some details open • Many new DJ mesons (LHCb) • new narrow states (2003): Ds*(2317) and Ds*(2460) , (and other broad states more recently) • masses significantly lower than quark model expectation, and just below DK and D*K threshold • Widths are only upper limits • Interpretation unclear: DK/D*K molecules, tetraquarks, chiral doublers, …? Sensitive to width
Ds0*(2317) Theoretical Predictions Pure cs state Tetraquark state DK had. molecule Dynamically gen. res. DK had. molecule
Method: Threshold Scan • reaction: • excitation function only depends on m and Γof Ds(2317) • experimental accuracy determined by beam quality (Δp, σp/p), not by detector resolution
Simulation Results: Energy Scan Msum = Mmiss(Ds) + M(Ds) G = 100 keV
Summary of MC Simulations Work in progress... Ds1'(2536)+ Ds0(2317)+ Ds1(2460)+ x100 x100 20% 16% 9% Ds+ D0 p0 30% 58% 60%
Summary • Many charmonium and open charm states recently discovered • Nature of these states is not clear, for some it seems to be connected to the width • Pbar-P also sensitive to exotic JPC states • PANDA will be able to perform high resolution • Resonance scans and • Threshold scans • FAIR and PANDA progressing well towards realization
Thank you for you attention and Goodbye to Nara
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