1 / 18

Hybrids and Glueballs in the light of antiproton reactions

Hybrids and Glueballs in the light of antiproton reactions. pBar Workshop GSI, 5.4.2002 Klaus Peters Ruhr-Universität Bochum. Light Mesons are complicated. naive quark-antiquark-picture is wrong for light mesons “leading“ meson-term is only the simplest of many Fock-states exception:

felton
Download Presentation

Hybrids and Glueballs in the light of antiproton reactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hybrids and Glueballs in the light of antiproton reactions pBar WorkshopGSI, 5.4.2002 Klaus PetersRuhr-Universität Bochum

  2. Light Mesons are complicated • naive quark-antiquark-picture is wrong for light mesons • “leading“ meson-term is only the simplest of many Fock-states • exception: • narrow states • (small mixing of states) • exotic quantum numbers • (reduced density of states) Klaus Peters - pBar Workshop - GSI

  3. Spectroscopy of Light Mesons • No/small problem with statistics • Interpretation biased by models(poles, couplings) • Problem: interpretation of measured states • less precise predictions • density of states • width of states • mixing of states Klaus Peters - pBar Workshop - GSI

  4. Exotic-Production via FSI Klaus Peters - pBar Workshop - GSI

  5. LQCD-Potentials • Comparison between quenched/unquenched • shows compatibility for bbBar-Potentials • sfD(stat) = 1% • unquenched calc:200 PCs for 3 months • Vital field • with large algorithmic improvements and improved systematic corrections Klaus Peters - pBar Workshop - GSI

  6. Gluonic Degrees of Freedom - Hybrids • Gluonic excitations of the quark-antiquark-potential may lead to bound states • LQCD: mH ~ 4.2-4.5 GeV • Light charmed hybrids could be as narrow as® O(5-50 MeV) • selection rules • small # of charmed final states (Zweig-Rule) Klaus Peters - pBar Workshop - GSI

  7. Charmed Hybrids • Fluxtube ® DD** , but if mH<4,29 GeV ®GH<50 MeV • Some exotics can decay neither to DD nor to DD* • e.g.: JPC(H)=0+- • fluxtube allowed J/yf2, J/y(pp)S,h1ch • fluxtube forbiddencc0w,cc0f, cc2w,cc2f, hch1 • Small # of final states with small phasespace CLEO-II B®J/yfK(S)(±) Klaus Peters - pBar Workshop - GSI

  8. Density of states (e.g. for Vector Mesons) • Light mesons have usually larger widths • Since NQ=3 for (uds) combinatorics yieldsvery many states • Ideal: charm-Sectorwith a much reduced density of states Klaus Peters - pBar Workshop - GSI

  9. Exotic Production in Proton-Antiproton • High production yields for exotic mesons (or with a large fraction of it) • f0(1500)p® ~25 % in 3p0 • f0(1500)p® ~25 % in 2hp0 • p1(1400)p® >10 % in p±p0h • Interference with other (conventional) states is mandatory for the phase analysis • Exotics are present ! Klaus Peters - pBar Workshop - GSI

  10. Hybrid Formation inin Proton-Antiproton • Gluon rich process creates gluonic excitation directly • since ccBar requires the quarks to annihilate (no rearrangement) • yields comparable to production of excited charmonium • 2 complementary techniques • Formation (Broad- and Fine-Scans) • Production (Fixed-Momentum) • Momentum for an complete survey p®~15 GeV Klaus Peters - pBar Workshop - GSI

  11. Mass regions and p momentum • Neccesary momentum span is driven by the charm-exotics • Hybrids (HC) • HC non-exotic JPCFormation ®10 GeV/c • HC exotic JPCProduction ®15 GeV/c • D(s)-Hybrids • DsDs+1 GeV/c ~12 GeV/c • Charmed Multiquarks (MC) • MCl+l-®15 GeV/c Perfect Resolution +Recoil-Particle +Phsp. Klaus Peters - pBar Workshop - GSI

  12. Gluonic Degrees of Freedom - Glueballs • Light gg/ggg-systems are complicated to identify • Exotic heavy glueballs • m(0+-) = 4140(50)(200) MeV • m(2+-) = 4740(70)(230) MeV • Width unknown, but! nature invests more likely in mass than in momentum • Flavour-blindness predicts decays into charmed final states • Same run period as hybrids • In addition: scan m>2 GeV/c2 Morningstar und Peardon, PRD60 (1999) 034509 Morningstar und Peardon, PRD56 (1997) 4043 Klaus Peters - pBar Workshop - GSI

  13. 4-Quark Formation with DiLepton-Tag • Proton-Antiproton contains already a 4-Quark-System • Idea: Dilepton-Tag from Drell-Yan-Production • Advantages • trigger • less JPC-Ambiguities • 1200 E./day @ 12 GeV/c • 300 E./day @ 5-8 GeV/c • antiproton-Beam • (for L=1032cm-2s-1) Klaus Peters - pBar Workshop - GSI

  14. 3p0 Emin Eg cosq Lessons from LEAR • Full solid angleno missing particles (photons!) • Low thresholdelectromagnetic detector • KS-Trigger • Kaon ID @ high Energies Klaus Peters - pBar Workshop - GSI

  15. Annihilation in Flight – no longer a challenge! Peters, NPA 692 (2001)295 • Crystal Barrel has prooven that the annihilation in flight can be analyzed unambiguously • Formation: • twobody decays, where at least one particle carries spin! • Production: • integration of the production process or • small recoil momenta may reduce the available phsp. and the contributing waves dramatically Klaus Peters - pBar Workshop - GSI

  16. Channels, Signatures, Potential Problems • “Leading charmonia” • J/y, y‘, h(‘)c, ccj [DDbar] a.o.m.? • DiLeptons • e+e- (Ecal,Trk) [c.m.: usually fast, but slow for 4-Quark-Tag] • m+m- (Trk,Hcal) • Photon-Pairs • gg from ccBar (Ecal,no-Trk) • gg from p0 and h (Ecal) • f (f)-Tag • ff and recoil f (Trk,Cherenkov) Most information needed on trigger level ! Klaus Peters - pBar Workshop - GSI

  17. Required Features • “Usual” omni purpose features • Forward spectrometry: cosq ® 1for low multiplicity charged final states[low and medium energy scans] • Mandatory!“Fast” particle id (guess) for trigger purposes[hard and/or soft] • Threshold Cherenkov? In addition to a multi purpose device (DIRC)? Klaus Peters - pBar Workshop - GSI

  18. Summary • Exotics are present in proton-antiproton reactions • Light exotics are complicated to measure and to classify • Heavy exotics will show a clearer signature • Charged and neutral tracking together with efficient particle id e±/p± m±/p± and p±/K±and V0-finder is mandatory • Exclusiveness with flat efficieny for the full solid angle Klaus Peters - pBar Workshop - GSI

More Related