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Recent developments in charm meson spectroscopy: Chaos, confusion and craziness.

Ted Barnes BNL Seminar 18 Mar. 2008. Recent developments in charm meson spectroscopy: Chaos, confusion and craziness. Basic hadronics Making charmonium Spectrum of charmonium Exciting new developments (2003-present): D * s0 , D s1 , X(3872),…(X,Y,Z), Y(4260), Z(4430).

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Recent developments in charm meson spectroscopy: Chaos, confusion and craziness.

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  1. Ted Barnes BNL Seminar 18 Mar. 2008 Recent developments in charm meson spectroscopy: Chaos, confusion and craziness. Basic hadronics Making charmonium Spectrum of charmonium Exciting new developments (2003-present): D*s0, Ds1, X(3872),…(X,Y,Z), Y(4260), Z(4430). Theory abstracted from T.Barnes, S.Godfrey and E.S.Swanson, PRD72, 054026 (2005). For BABAR, BELLE, BES, CLEO, GSI, … : All 40 cc states expected to 4.42 GeV, all 139 of their open flavor strong modes and partial widths, all 231 o.f. strong decay amplitudes, all 153 E1 and (some) M1 EM widths. Phew.

  2. 1. Basic hadronics.

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

  7. 2. Making charmonium.

  8. How to make charmonium? Hit things together. e+e- collisions (as in Beijing, Cornell, SLAC) “clean” theoretically but small cross sections and restricted quantum numbers hadron-hadron collisions e.g. pp Fermilab (past), GSI/Darmstadt (start 2013 AD) messy theoretically, large backgrounds, less restricted quantum numbers …some Feynman diagrams:

  9. e+e- collisions (1): e- g y hadrons e+ The traditional approach: s-channel annihilation. Restricted to JPC = 1 - - . s = O(a2). (May then use hadronic or radiative transitions to reach other states.)

  10. e+e- collisions (2): “Two-photon collisions”. Forms positive C-parity charmonia. (esp. JPC = 0 - +, 0 + +, 2 + +). Quite small cross sections, s = O(a4), so requires high intensity e+e- beams.

  11. e+e- collisions (3): “B factories” bb Surprisingly effective for making charmonia. The source of several recent discoveries in this field.

  12. pp collisions : Used at Fermilab (E760 and E835). Planned for GSI/Darmstadt (PANDA facility).

  13. 3. The spectrum of charmonium. Pre-dawn, a lava field near Carrizozo, New Mexico.

  14. 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.

  15. 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…

  16. 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

  17. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model blue = expt, red = theory. Two narrow states are expected, with JPC = 2- + and 2- -. The 1D multiplet is theoretically close to degenerate, near the 3D1 y(3770). L*S OGE – L*S conft, T OGE S*S OGE

  18. 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.

  19. Best recent LQCD ref for ccbar and cc-H spectroscopy: “Charmonium excited state spectrum in lattice QCD.” J.J.Dudek, R.G.Edwards, N.Mathur and D.G.Richards, arXiv:0707.4162 [hep-lat], Phys.Rev.D77:034501,2008. Results for cc still rather difficult to distinguish from quark model. Ambiguity in the 1- + exotic noted. (However other exotics again appear around 4.5 GeV.) (J - + spectrum) M [MeV]

  20. End of Introduction to cc

  21. 4. The new “XYZ” states: 2P cc? 3S cc? Molecules? cc hybrids? Nonresonant enhancements? Experimental errors? How to test these possibilities? Recommended reading: “The New Heavy Mesons: A Status Report” E.S.Swanson, Phys. Reports 429, 243-305 (2006). “What’s new with the XYZ mesons?” S.L.Olsen, arXiv:0801.1153v3 [hep-ex]13 Feb 2008. “The Exotic XYZ Charmonium-like Mesons.” S.Godfrey and S.L.Olsen, arXiv:0801.3867 [hep-ph] Jan 2008. submitted to Ann. Rev. Nucl. Part. Phys.

  22. “Selections from…” (Godfrey and Olsen review, list of new states):

  23. 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?

  24. … but first, the first of the new discoveries: new, unexpected, very long-lived mesons in the cs sector! D*s0 (2317) and Ds1(2457) cs mesons or DK molecules? (or both)

  25. e+e- collisions (3): “B factories” Surprisingly effective for making charmonia. The source of several recent discoveries in this field.

  26. Where it all started. BABAR: D*s0(2317)+ in Ds+p0 D.Aubert et al. (BABAR Collab.), PRL90, 242001 (2003). M = 2317 MeV (2 Ds channels), G < 9 MeV (expt. resolution) “Who ordered that !?” - I.I.Rabi, about the m- Since confirmed by CLEO, Belle and FOCUS. (Theorists expected L=1 cs states, e.g. JP=0+, but with a LARGE width and at a much higher mass.) …

  27. And another! CLEO: Ds1(2460)+ 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. A JP=1+partner of the 0+ D*s0(2317)+cs ?

  28. (Godfrey and Isgur potential model.) Prev. (narrow) expt. states in gray. DK threshold What caused large downwards mass shifts? Mixing with 2 meson continuum states? (Believed true.)

  29. L’oops [ J/y - M1M2 - J/y ] 3P0 decay model, std. params. and SHO wfns. M1M2 DM [J/y] PM1M2[J/y] DD- 23. MeV 0.021 DD*- 83. MeV 0.066 famous 1 : 4 : 7 ratio DD :DD* : D*D* D*D*- 132. MeV 0.094 DsDs - 21. MeV 0.015 DsDs*- 76. MeV 0.048 Ds*Ds*- 123. MeV 0.072 Sum =- 457. MeVPcc = 69.% VERY LARGEmass shift and large non-cc component! Can the QM really accommodate such large mass shifts??? Other “cc” states?

  30. L’oops [ cc - M1M2 - cc ] 3P0 decay model, std. params. and SHO wfns. Loops produce a roughly state-independent overall negative mass shift !

  31. L’oops [ cc - M1M2 - cc ] 3P0 decay model, std. params. and SHO wfns. Loop mass shifts of states within L,S cc multiplets are analytically identical if the initial masses are equal, if you sum over multiplets of loop spin states! (A theorem in:) “Hadron Loops: General Theorems and Application to Charmonium” T.Barnes and E.S.Swanson, arXiv:0711.2080 [hep-ph] (Nov.2007)

  32. X(3872) a charmed meson molecule?

  33. Fitted and predicted cc spectrum Coulomb (OGE) + linear scalar conft. potential model blue = expt, red = theory. Two narrow states are expected, with JPC = 2- + and 2- -. The 1D multiplet is theoretically close to degenerate, near the 3D1 y(3770). L*S OGE – L*S conft, T OGE S*S OGE

  34. BelleCollab. K.Abe et al, hep-ex/0308029; S.-K.Choi et al, hep-ex/0309032, PRL91 (2003) 262001. X(3872) from KEK B+ / - -> K+ / -p+p-J/ Y Alas the known y(3770) = 3D1cc. If the X(3872)is 1D cc, an L-excited multiplet is split much more than expected assuming scalar confinement. G < 2.3MeV M = 3872.0 +- 0.6 +- 0.5 MeV Accidental agreement? X = cc (2- + or 2- - or …), or a DD* molecule? M( Do + D*o) = 3871.5 +- 0.5 MeV n.b. M( D+ + D*-) = 3879.5 +- 0.7MeV

  35. CDF II Collab. D.Acosta et al, hep-ex/0312021, PRL. X(3872) confirmation (from Fermilab) n.b. most recent CDF II: M = 3871.3 pm 0.7 pm 0.4 MeV X(3872) also confirmed by D0Collab. at Fermilab. Perhaps also seen by BaBar OK, it’s real… n.b. molecule.ne.multiquark

  36. 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?)

  37. X(3872) 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 y(3770) = 3D1 cc. If the X(3872)is 1D cc, an L-multiplet is split much more than expected assuming scalar conft. G < 2.3MeV Accidental agreement? X = cc 2- + or 2- - or …, or a molecular (DD*) state? M = 3872.0 +- 0.6 +- 0.5 MeV M( Do + D*o) = 3871.5 +- 0.5 MeV n.b. M( D+ + D*-) = 3879.5 +- 0.7MeV Charm in nuclear physics???

  38. DD* molecule options This possibility is suggested by the similarity in mass, M(X) = 3872.0 +- 0.6 +- 0.5 MeV M( Do + D*o) = 3871.5 +- 0.5 MeV N.A.Tornqvist, PRL67, 556 (1991); hep-ph/0308277. F.E.Close and P.R.Page, hep-ph/0309253, PLB578, 119 (2004). C.Y.Wong, hep-ph/0311088. E.Braaten and M.Kusunoki, PRD69, 074005 (2004). E.S.Swanson, PLB588, 189 (2004); PLB589, 197 (2004). n.b. The suggestion of charm meson molecules dates back to 1976: Y(4040) as a D*D* molecule; (Voloshin and Okun; deRujula, Georgi and Glashow). n.b.2 Could the signal simply be a cusp due to new DD* channels opening?

  39. Interesting prediction of molecule decay modes: E.S.Swanson: 1+ +DoD*o molecule - maximally isospin violating! with additional comps. due to 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. Appears to be confirmed experimentally! Nothing about the X(3872) is input: this all follows from OpE and C.I.

  40. Z(3930) a 23P2 charmonium state?

  41. e+e- collisions (2): “Two-photon collisions”. Forms positive C-parity charmonia. (esp. JPC = 0 - +, 0 + +, 2 + +). Quite small cross sections, s = O(a4), so requires high intensity e+e- beams.

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

  43. 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

  44. X(3940) and double charmonium production

  45. e+e- collisions (5): Double charmonium production. J/y C=(+) cc The traditional approach, s-channel annihilation, but can now make C=(+) charmonia! JPC =JP+

  46. 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’’.

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

  48. Y(4260) a charmonium hybrid?

  49. 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!

  50. e+e- collisions (6): Initial state radiation (ISR) J/y The traditional approach, s-channel annihilation, but can use higher energy beams. Still restricted toJPC = 1 - -.

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