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Exploring Charmonium Physics: The XYZs of CC

Delve into the realm of charmonium physics, from good old charmonium to the new states and exotic possibilities. Learn about QCD flux tubes, hybrid particles, and quark model mesons and baryons. Discover the spectrum of charmonium states and the decay mechanisms at play. Explore the theoretical models and experimental findings in this fascinating domain of particle physics.

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Exploring Charmonium Physics: The XYZs of CC

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  1. T. Barnes ORNL / UTenn SLAC HEP Seminar 23 Feb. 2006 The XYZs of cc: X(3943), Y(3943), Z(3931) and Y(4260) 1. Good old charmonium. 2. The new states: 3S cc? 2P cc? cc hybrids? How to test these possibilities. New theor. results mainly abstracted from: T.Barnes, S.Godfrey and E.S.Swanson, hep-ph/0505002, PRD72, 054026 (2005).

  2. 1. Good old charmonium.

  3. 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)

  4. (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” :

  5. 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

  6. 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).

  7. The (higher) cc spectrum Pre-dawn, a lava field near Carrizozo, New Mexico.

  8. Charmonium (cc) A nice example of a QQ spectrum. Expt. states (blue) 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.

  9. 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…

  10. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model blue = expt, red = theory. L*S OGE – L*S conft, T OGE as= 0.5538 b = 0.1422 [GeV2] mc = 1.4834 [GeV] s = 1.0222 [GeV] S*S OGE

  11. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model NR model (LHS) adjacent to GI model (RHS). 1F 2P GI NR S*S OGE

  12. cc from LGT A LGT e.g.: X.Liao and T.Manke, hep-lat/0210030 (quenched – no decay loops). Broadly consistent with the cc potential model. No cc radiative or strong decay predictions from LGT yet. <-1- + exotic cc-H at 4.4 GeV Small L=2 hfs. 1+ - cc has returned.

  13. Strong decays

  14. 4040 4415 3770 4160 Strong widths of cc resonances

  15. What are the total widths of cc states above 3.73 GeV? (These are dominated by open-flavor decays.) 43(15) MeV 78(20) MeV 52(10) MeV < 2.3 MeV X(3872) 23.6(2.7) MeV PDG values

  16. g0 g0 br vector confinement??? controversial Experimental R summary (2003 PDG) How do open-flavor strong decays happen at the QCD (q-g) level? Very interesting open theoretical question: Do strong decays use the3P0model decay mechanism orthe Cornell model decay mechanism or … ? e+e-, hence 1-- cc states only. “Cornell” decay model: (1980s cc papers) (cc) <-> (cn)(nc) coupling from qq pair production by linear confining interaction. Absolute norm of G is fixed!

  17. An alternative strong decay model The 3P0 decay model: 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.

  18. One success of strong decay models An historical SLAC puzzle explained: the weakness of y(4040) -> DD e.g. DD molecule? After restoring this “p3 phase space factor”, the BFs are: D0D0 : D0D*0 : D*0D*0 0.12 +/- 0.06 0.95 +/- 0.19 [1] +/- 0.31

  19. Theor R from the Cornell model. Eichten et al, PRD21, 203 (1980): 4415 4040 4159 D*D* DD* DD Y(4040) Y(4040) partial widths [MeV] (3P0 decay model): DD = 0.1 DD* = 32.9 D*D*= 33.4 [multiamp. mode] DsDs= 7.8 Y(4040) ->D*D* amplitudes (3P0 decay model): 1P1 = +0.034 5P1 = -0.151 = - 2 * 51/2 *1P1 5F1 = 0 famous nodal suppression of a 33S1Y(4040) cc-> DD std. cc and D meson SHO wfn. length scale

  20. 2. The new XYYZ states: 3S cc? 2P cc? cc hybrids? How to test these possibilities.

  21. Expt. preview, M, G and modes,X(3943),Y(3943), Z(3931): J/y

  22. BGS, hep-ph/0505002, PRD72, 054026 (2005). Possible new cc states at these masses! Z;X,Y;Y Reminder: Three as yet unknown 1D states. Predicted to have G < 1 MeV! cc spectrum, potential models (dashed: nonrel L, Godfrey-Isgur R) vs data 2P or not 2P?

  23. cc spectrum, potential models (dashed: nonrel L, Godfrey-Isgur R) vs data Possible new C=(+) cc states from e+e- ! 2P or not 2P?

  24. An interesting new charmonium production mechanism! Allows access to C=(+) cc states in e+e- w/o using gg. X(3943) X(3943) hc’ hc c0 No c1or c2 !? [ref] = Belle, hep-ex/0507019, 8 Jul 2005. n.b. Eichten: X(3943) may be the 31S0 cchc’’.

  25. Strong Widths: 3P0 Decay Model 3S 33S1 74 [MeV] 31S0 80 [MeV] DD DD* D*D* DsDs X(3943) Maybe not 2P? X(3943) = 31S0hc” ? (Eichten) 52(10) MeV X(3872)

  26. Back to the main theme: Comparing expt. with theory for 2P cc states. 1st Strong decays (vs. expt.) 2nd EM (g and gg transitions)

  27. Trivial observations for 2P cc open-charm strong decays: Thresholds DD 3.73 GeV DD* 3.87 GeV (Ds Ds 3.94 GeV - small) JP-allowed D, D* modes (M < D*D*) c2’ 2++ 23P2 DD, DD* c1’ 1++ 23P1 DD* c0’ 0++ 23P0 DD hc’ 1+- 21P1 DD* but C = (-) Looking for both DD and DD* is a good filter! n.b. JP = 1+DD* final states have both S and D amps. Detailed 2P cc predictions…

  28. 2P cc Strong Widths: 3P0 Decay Model 23P2 80 [MeV] 23P1 165 [MeV] 23P030 [MeV] 21P1 87 [MeV] 2P DD DD* DsDs (assuming NR cc potential model masses; BGS, hep-ph/0505002, PRD72, 054026 (2005).)

  29. Y(3943) B-> KY(3943), Y->wJ/y [ref] = Belle, PRL94, 182002 (2005).

  30. Y(3943) Y(3943) = 23P1 cc?(Too light for cc-H.) Gtot Expt for Y(3943): B -> KY(3943), Y->wJ/y G= 87 +/- 22 MeV 1++ cc ->wJ/yis unusual; cc-> virtual DD* e.g. ->wJ/y ? n.b.c1IS seen in B decays theory expt. Theory for 23P1(3943): G= 135 MeV A strong DD* mode $? The only open-charm mode?

  31. Z(3931) gg->Z(3931)-> DD [ref] = Belle, hep-ex/0507033, 8 Jul 2005.

  32. Z(3931) Z(3931) = 23P2 cc ? (suggested by Belle) Expt for Z(3931): gg -> Z(3931) -> DD G = 20 +/- 8 +/- 3 MeV Ggg* BDD = 0.23 +/- 0.06 +/- 0.04 keV Theory for 23P2(3931): G= 47 MeV DD*/DD = 0.35 Ggg* BDD = 0.47 keV (Ggg from T.Barnes, IXth Intl. Conf. on gg Collisions, La Jolla, 1992.) The crucial test of Z(3931) = 23P2 cc : DD* mode $? Gtot thy expt Gggin http://web.utk.edu/~tbarnes/website/Barnes_twophot.pdf

  33. Expt for Z(3931): gg -> Z(3931) -> DD G= 20 +/- 8 +/- 3 MeV Ggg* BDD = 0.23 +/- 0.06 +/- 0.04 keV Theory for 23P0(3931): G: DD only o.c. mode, theor. tiny! (node) Annih. dominates? Recall G(c0)ca. 10MeV. Ggg ca. 2 keV (not calc.) Ggg* BDD << 2 keV. Another possibility for Z(3931)??? Z(3931) Another possibility for Z(3931)???

  34. EM transitions (How one might make 2P cc states.) What radiative partial widths do we expect from various initial 1- - cc states to 2P cc states?

  35. Strong Widths: 3P0 Decay Model 3S 33S1 74 [MeV] 31S0 80 [MeV] DD DD* D*D* DsDs X(3872) 52(10) [MeV]

  36. E1 Radiative Partial Widths 3S -> 2P 33S1->23P214 [keV] 33S1->23P139 [keV] 33S1->23P054 [keV] 31S0->21P1105 [keV] 3S -> 1P 33S1->3P2 0.7 [keV] 33S1->3P1 0.5 [keV] 33S1->3P0 0.3 [keV] 31S0->1P19.1[keV]

  37. Strong Widths: 3P0 Decay Model 23D3 148 [MeV] 23D2 92 [MeV] 23D1 74 [MeV] 21D2 111 [MeV] 2D DD DD* D*D* DsDs DsDs* 78(20) [MeV]

  38. E1 Radiative Partial Widths 23D3 -> 23P2239 [keV] 23D2->23P2 52 [keV] 23P1298 [keV] 23D1->23P2 6 [keV] 23P1168 [keV] 23P0483 [keV] 21D2->21P1 336 [keV] 2D -> 2P 2D -> 1F 23D3 -> 3F4 66 [keV] -> 3F3 5 [keV] -> 3F2 14 [keV] 23D2-> 3F3 44 [keV] 3F2 6 [keV] 23D1->3F251 [keV] 21D2->1F3 54 [keV] 23D3 -> 3P2 29 [keV] 23D2-> 3P2 7 [keV] 3P1 26 [keV] 23D1->3P2 1 [keV] 3P1 14 [keV] 3P0 27 [keV] 21D2->1P1 40 [keV] 2D -> 1P

  39. Y(4260)

  40. cc spectrum, potential models (dashed: nonrel L, Godfrey-Isgur R) vs data Possible 1- - state Y(4260). Note no plausible cc assignment exists. A1- - charmonium hybrid??

  41. Y(4260) e+e- -> Y(4260)ISR, Y -> p+p-J/y [ref] = BaBar, PRL95, 142001 (2005). Not seen in R. Hmmm?! log scale

  42. Y(4260) ? B- -> K- Y(4260), Y -> p+p-J/y [ref] = BaBar, hep-ex/0507090 (21 Jul 2005).

  43. cc-hybrids, theory

  44. Characteristics of cc-hybrids. (folklore, mainly abstracted from models, some LGT) States (flux-tube model): The lightest hybrid multiplet should be a roughly degenerate set containing 3 exoticand 5 nonexotic JPC; 0+-, 1-+, 2+-, 0-+,1+-,2-+, 1++,1-- Mass ca. 4.0 – 4.5 GeV, with LGT preferring the higher range. The 1-- should be visible in e+e- but with a suppressed width. (Hybrid models for different reasons predict ycc(r=0) = 0, suppressing Gee .) Decays (flux-tube model and f-t decay model): Dominant open-charm decay modes are of S+P type, not S+S. (e.g. DD1 not DD or DD*). n.b. p1(1600) ->p h’ argues against this model. LGT(UKQCD): Closed-charm modes like cc-H -> cc + light mesons are large! (Shown for bb-H; (bb) is preferentially P-wave, and “light mesons” = scalar pp.)

  45. E.I.Ivanov et al. (E852) PRL86, 3977 (2001). p1(1600) The (only) strong JPC-exotic H candidate signal. p-p ->p-h’p p1(1600) 1-+ exotic reported in p-h’ ph’is a nice channel because nn couplings are weak for once (e.g. the a2(1320) noted here). The reported exotic P-wave is dominant!

  46. 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. No LGT cc radiative or strong decay predictions yet. 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)? Small L=2 hfs.

  47. PRD52, 5242 (1995). Early cc-H mass estimates:

  48. cc-H mass result, 1995 BCS flux tube model calculation ([ref] on prev. slide):

  49. QQ-H closed-flavor decays from LGT:

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