1 / 35

From Heavy Q to Light q Systems

DOE NP Town Meeting Rutgers U. 12-14 Jan 2007. Ted Barnes Physics Div. ORNL Dept. of Physics and Astronomy, U.Tenn. From Heavy Q to Light q Systems. 1. What hadrons exist in nature? Quarkonia / Baryons / Hybrids / Glueballs / Multiquarks 2. Recent developments in c c (noises off)

wilmet
Download Presentation

From Heavy Q to Light q Systems

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. DOE NP Town Meeting Rutgers U. 12-14 Jan 2007 Ted Barnes Physics Div. ORNL Dept. of Physics and Astronomy, U.Tenn. From Heavy Q to Light q Systems 1. What hadrons exist in nature? Quarkonia / Baryons / Hybrids / Glueballs / Multiquarks 2. Recent developments in cc(noises off) 3. Where we will boldly go if time permits: Status of light qqH G (M) Next: J.Dudek (light mesons), A.Dzierba (on GlueX@Jlab) (Meson Spectroscopy Theory Overview)

  2. LGT simulation showing the QCD flux tube Color singlets and QCD exotica “confinement happens”. Q Q R = 1.2 [fm] “funnel-shaped” VQQ(R) linear conft. (str. tens. = 16 T) Coul. (OGE) QCD flux tube (LGT, G.Bali et al.; hep-ph/010032)

  3. (q2q2),(q4q),… (q3)n, (qq)(qq),(qq)(q3),… multiquark clusters nuclei / molecules dangerous e.g. Q(1540) ca. 106 e.g.s of (q3)n, maybe 1-3 others X(3872) = DD*! g2, g3,… qqg, q3g,… q2q2, q4q,… glueballs hybrids multiquarks maybe 1 e.g. maybe 1-3 e.g.s Physically allowed hadron states (color singlets) (naïve, valence) _ Conventional quark model mesons and baryons. qq q3 100s of e.g.s Basis state mixing may be very important in some sectors. “exotica” :

  4. Quarkonia qq mesonsstates The quark model treats conventional mesons as qq bound states. Since each quark has spin-1/2, the total spin is Sqq tot = ½ x ½ = 1 + 0 Combining this with orbital angular momentum Lqqgives states of total Jqq = Lqqspin singlets Jqq = Lqq+1, Lqq, Lqq-1spin triplets

  5. qq mesonsquantum numbers ParityPqq = (-1)(L+1) C-parity Cqq = (-1)(L+S) The resulting qq NL states N2S+1LJ have JPC= 1S: 3S11-- ; 1S00 -+ 2S: 23S11-- ; 21S00 -+ … 1P: 3P22+ + ; 3P11+ + ; 3P00+ + ; 1P11+-2P … 1D: 3D33- - ; 3D22- - ; 3D11- - ; 1D22-+2D … JPC forbidden to qq are called “JPC-exotic quantum numbers” : 0- - ; 0+ - ; 1- + ; 2+ - ; 3- + … Plausible JPC-exotic candidates = hybrids, glueballs (high mass), maybe multiquarks (fall-apart decays).

  6. Developments in the cc sector (noises off)

  7. Charmonium (cc) A nice example of a QQ spectrum. Expt. states are shown with the usual L classification. Above 3.73 GeV: Open charm strong decays (DD, DD* …): broader states except 1D2 2- +, 2- - 3.73 GeV Below 3.73 GeV: Annihilation and EM decays. (rp, KK* , gcc, gg, l+l-..): narrow states.

  8. Contact S*S from OGE; Implies S=0 and S=1 c.o.g. degenerate for L > 0. (Not true for vector confinement.) Minimal quark potential model physics: OGE + linear scalar confinement; Schrödinger eqn (often relativized) for wfns. Spin-dep. forces, O(v2/c2), treated perturbatively. Here…

  9. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model black = expt, red = theory. DD states fitted S*S OGE

  10. A LGT cc-sector spectrum e.g.: X.Liao and T.Manke, hep-lat/0210030 (quenched – no decay loops) Broadly consistent with the cc potential model. Need LGT cc radiative and strong decay predictions! cc and cc–H from LGT <-1- + exotic cc-H at 4.4 GeV n.b. The flux-tube model of hybrids has a lightest multiplet with 8 JPCs; 3 exotics and 5 nonexotics, roughly degenerate: (0,1,2) +- /-+, 1++,,1- -. Y(4260), Y(4350)? Small L=2 hfs.

  11. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model black = expt, red = theory. Y(4350) JPC = 1- - Y(4260) JPC = 1- - Z(3930) JPC = 2++ ; X(3940), Y(3940) C = (+) DD* X(3872) JPC = 1++ DD S*S OGE

  12. X(3872) Molecules and Multiquarks BelleCollab. K.Abe et al, hep-ex/0308029; S.-K.Choi et al, hep-ex/0309032, PRL91 (2003) 262001. B+ / - -> K+ / -p+p-J /Y n.b. molecule.ne.multiquark G < 2.3MeV M = 3872.0 +- 0.6 +- 0.5 MeV A DD* molecule?! M( Do + D*o) = 3871.5 +- 0.5 MeV n.b. M( D+ + D*-) = 3879.5 +- 0.7MeV Charm in nuclear physics???

  13. Isospin “violation” in molecule decays: a signature E.Swanson, hep-ph/0311229, PLB588, 189 (2004): 1+ + DoD*o + … molecule (additional comps. due to off-diagonal FSI rescattering). J/yro J/y“w” Predicted total width ca. = expt limit (2 MeV). Very characteristic mix of isospins: comparable J/yroandJ/y“w”decay modes expected. Now appears confirmed. (maybe) Nothing about the X(3872) is input: this all follows from OpE and C.I.

  14. The trouble with multiquarks: “Fall-Apart Decay” (actually not a decay at all: no HI) Multiquark models found that most channels showed short distance repulsion: E(cluster) > M1 + M2. Thus no bound states. Only 1+2 repulsive scattering. Exceptions: 2) E(cluster) < M1 + M2, bag model: u2d2s2 H-dibaryon, MH - MLL = - 80 MeV. n.b. LLhypernuclei exist, so this H was wrong. 1) nuclei and hypernuclei weak int-R attraction allows “molecules” “VLL(R)” VNN(R) -2mN -2mL 3) Heavy-light R R Q2q2 (Q = b, c?)

  15. Where it all started: The BABAR state D*sJ(2317)+ in Ds+p0 D.Aubert et al. (BABAR Collab.), PRL90, 242001 (2003). M = 2317 MeV (2 Ds channels), G < 9 MeV (expt. resolution) (Theorists expected L=1 cs states, e.g. JP=0+, but with a LARGE width and at a much higher mass.) …

  16. And another! The CLEO state D*sJ(2463)+ in Ds*+p0 D.Besson et al. (CLEO Collab.), PRD68, 032002 (2003). M = 2463 MeV, G < 7 MeV (expt. resolution) Since confirmed by BABAR and Belle. M = 2457 MeV. JP=1+partner of the D*s0(2317)+cs?

  17. (Godfrey and Isgur potential model.) Prev. (narrow) expt. states in gray. DK threshold

  18. Light ( = u,d,s,g) mesons What we theorists expect and will be proven wrong about.

  19. GlueX regime (ALL mesons in this range) Light qq (I=1 u,d shown) Approx. status, light (u,d,s) qq spectrum to ca. 2.1 GeV. I=1 shown, dashed = expected Well known to ca. 1.5 GeV, poorly known above (except for larger-J). n.b. ss is poorly known generally. Several recent candidates, e.g. a1(1700), a2(1750). Strong decays give M, G, JPCofqq candidates.

  20. (Light) Hybrids: New band of meson excitations predicted, starting at ca. 1.9 GeV. Flavor nonets x 8 JPC = 72 states. Includes 0+-, 1-+ and 2+- JPC-exotics.

  21. Strong Decays Open-charm strong decays: 3P0 decay model (Orsay group, 1970s) qq pair production with vacuum quantum numbers. LI = g y y . A standard for light hadron decays. It works for D/S in b1-> wp. The relation to QCD is obscure.

  22. Extensive strong decay tables(ca. 1985-present) Mainly light (u,d,s) hadrons in f.-t. or 3P0models. A few references: qq meson decays: S.Godfrey and N.Isgur, PRD32, 189 (1985). T.Barnes, F.E.Close, P.R.Page and E.S.Swanson, PRD55, 4157 (1997). [u,d mesons] T.Barnes, N.Black and P.R.Page, PRD68, 054014 (2003).[strange mesons][43 states, all 525 modes, all 891 amps.] T.Barnes, S.Godfrey and E.S.Swanson, PRD72, 054026 (2005). [charmonia: 1st 40 cc mesons, all open-charm strong decay amps, all E1 and many M1 transitions] F.E.Close and E.S.Swanson, PRD72, 094004 (2005). [open-charm mesons: D and Ds] qqq baryon decays: S.Capstick and N.Isgur, PRD34, 2809 (1986). S.Capstick and W.Roberts, PRD49, 4570 (1994); PPNP 45, S241-S331 (2000). [BPs, BV modes of u,d baryons] Example of the detailed theor. predictions for light qq meson strong decays:

  23. Some results for strange meson decays (BBP paper): 3F4 ss (max J) typically ARE dominated by the lowest few allowed modes. (Cent. barrier.) The five narrowest unknown (?) ssbar states below 2.2 GeV: stateGtotFavored modes[expt?] 1) 2- + 21D2 h2(1850)129 MeVKK*[WA102 h2(1617)-h2(1842): nn <-> ss mixing?] 2) 4+ + 13F4f4(2200)156 MeVK*K*, KK, KK*[LASS 2209; Serp. E173 2257] 3) 0- + 31S0hs(1950) 175 MeVK*K*, KK* 4)1+ + 21P1 h1(1850)193 MeV KK*, K*K*, hf [ss filter] 5)2- - 13D2f2(1850)214 MeV KK*, hf 3F2 ss -> K1(1273) K confirms Blundell and Godfrey. 3F3 ss -> K2*K dominant

  24. (Light) Hybrids Hybrid = qq“g” states (with q=u,d,s) span flavor nonets, hence there are many experimental possibilities. Models agree that the lightest hybrid multiplet contains JPC-exotics. f.t. model predicts 8 JPC x 9 flavors = 72 “extra” resonances at the hybrid threshold. 3/8 JPC are exotic, 0+-, 1-+, 2+-. The remainder, 0-+, 1+-, 2-+, 0+-, 1--, 1++ are “overpopulation” rel to the quark model. Mestm ca. 1.5 - 2.0 GeV. f.t. 1.9 GeV is famous. LGT mass similar to f.t. for 1-+ . JPC = 1-+ with I=1, “p1”, is especially attractive. It is predicted in the f.t. model to be relatively narrow and to have unusual decay modes.

  25. Hybrid Meson Decays: flux-tube model N.Isgur, R.Kokoski and J.Paton, PRL54, 869 (1985). Gluonic Excitations of Mesons: Why They Are Missing and Where to Find Them. HL=1 -> S+P p1 -> b1p, f1p

  26. Expt Hybrid mesons? The current best signal for a JPC = 1-+ exotic. (Can’t be qq.) E852@BNL, ca. 1996 p-p -> (p-h’) p (Current best of several reactions with claims of exotics.) p1(1600) a2(1320) qq n.b. NOT an “S+P” flux tube favored mode! exotic

  27. p2(2000) hybrid; b1p mode F.E.Close and P.R.Page, NPB443, 233 (1995). Close and Page: some notably narrow nonexotic hybrids in the f-t model w(2000) hybrid

  28. Hybrid baryons Spectrum of light (n=u,d) hybrid baryons. S.Capstick and P.R.Page, nucl-th/0207027, Phys. Rev. C66 (2002) 065204. (flux tube model) M (MeV) lightest hybrid baryons, flux tube model overpopulation of the qqq quark model, starting with 1/2+, 3/2+ ca. 1870 MeV

  29. Glueballs Theor. masses (LGT) The glueball spectrum from an anisotropic lattice study Colin Morningstar, Mike Peardon Phys. Rev. D60 (1999) 034509 New I=0 mesons starting with 1 scalar at ca. 1.6 GeV. Then no states until > 2 GeV. No JPC-exotics until 4 GeV.

  30. Scalar glueball discovery? Crystal Barrel expt. (LEAR@CERN, ca. 1995) pp->p0 p0 p0 Evidence for a scalar resonance, f0(1500) ->p0 p0 n.b. Some prefer a different scalar, f0(1710) -> hh, KK. PROBLEM: Neither f0 decays in a naïve glueball flavor-symmetric way to pp, hh, KK. qq<-> G mixing?

  31. (Light) Molecules: “Extra” hadrons just below two-hadron thresholds. S-waves easiest – look for quantum numbers of an S-wave pair. Nuclei are examples… MANY molecules exist! Can’t predict molecules w/o understanding soft 2 -> 2 hadron scattering. Add X(3872) to the list of molecules!

  32. L’oops Future: “Unquenching the quark model” Virtual meson decay loop effects, qq<-> M1 M2 mixing. e.g. DsJ* states (mixed cs<-> DK …, how large is the mixing?) Are the states close to |cs> or |DK>, or are both basis states important? A perennial question: accuracy of the valence approximation in QCD. Also LGT-relevant (they are often quenched too).

  33. Summary regarding meson spectroscopy: Theorists expect new types of mesons (glueballsand hybrids) starting at ca. 1.5 - 2 GeV. A few candidates exist. Looking for JPC-exotics is a good strategy. Also overpopulation - need to better establish the qq sector above 1.5 GeV and ss! Charm mesons (cs and cc sectors) have surprised people recently – low masses hence tiny widths; also perhaps new molecular states. Data on the spectrum is needed to compare with models and LGT. Strong and EM widths are also useful information. Strong decays are poorly understood in QCD. Exciting discoveries in meson spectroscopy are often serendipitous: J/Y Ds0*(2317) Ds1(2463) X(3872)

  34. Summary regarding GlueX at JLAB: (A.Dzierba presentation) • Photoproduction accesses exotic JPC easily (S=1 beam). • Several mechanisms, 2 are: • t-channel CEX, e.g. g (-> r0) + p+ - -> p1 • diffr., e.g. g + P -> 2 +- • (Also s- and u-channel baryon resonances.) • Detect ALL strong modes, hermetic, PWA. • You get the poorly explored ss sector for free. • Theorists can contribute by 1. LGT spectroscopy and decays, • 2. modeling photoproduction of both exotic and ordinary qq resonances • (CLAS data?).

  35. End

More Related