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Non-standard mesons

Non-standard mesons. Stephen L. Olsen University of Hawai’i. Representing Belle. Fermilab seminar May 10, 2005. test of QCD: “running” a s. Probe QCD from other directions. non-qq or non-qqq hadron spectroscopies: Pentaquarks: e.g. an S=+1 baryon Glueballs:

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Non-standard mesons

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  1. Non-standard mesons Stephen L. Olsen University of Hawai’i Representing Belle Fermilab seminar May 10, 2005

  2. test of QCD: “running” as

  3. Probe QCD from other directions non-qq or non-qqq hadron spectroscopies: Pentaquarks: e.g. an S=+1 baryon Glueballs: gluon-gluon color singlet states Multi-quark mesons: qq-gluon hybrid mesons d u u d s u c u c c c

  4. Pentaquarks? “Seen” in many experiments but not seen in just as many others Compass Jlab p BES Belle BaBar CDF High interest: 1st pentaquark paper has ~500 citations

  5. Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L3 Jlab(CLAS) (gpK+Ksn) Yes: 17 No: 18

  6. Existence of Pentaquarksis not yet established

  7. Narrow multi-quark mesons? • DsJ(2317) & DsJ(2457) • X(3872)ppJ/y CLEO BaBar M(Ds*p) M(Dsp) Belle M(ppJ/y)

  8. What are the DsJ states? Belle found B D DsJ(2317)  D DsJ(2457) and DsJ(2457)gDs

  9. J=1 J=1 J=0 J=2 Angular analysis for B D DsJ DsJDsp(g) J=0 z Jz=0 (p) DsJ(2460) Ds  DsJ(2317) Ds0 DsJ(2317) = 0+ DsJ(2547) = 1+

  10. DsJ fit into cs spectrum(with a mass shift) DsJ(2547) = 1+ DsJ(2317) = 0+

  11. DsJ states are likelyordinary L=1 cs mesons(with perhaps some tetraquark mixture) Potential models got the masses wrong Chiral models seem to work OK See, e.g. Bardeen, Eichten & Hill PRD68, 054024

  12. non-standard mesons with “hidden charm” u c u • standard cc mesons are: • best understood theoretically • narrow & non overlapping • c + c systems are commonly produced in B meson decays. c (i.e containing c & c) c c c c Vcb b W- cosqC s CKM favored

  13. Thanks to KEKB, Belle has lots of B mesons(>1M BB pairs/day) >1fb -1/day Design: 10 34

  14. Is the X(3872) non-standard? BK p+p-J/y y’p+p-J/y X(3872)p+p-J/y M(ppJ/y) –M(J/y)

  15. Its existence is well establishedseen in 4 experiments PRL 93, 072001 CDF 9.4s 11.6s X(3872) PRL 93, 162002 D0 PRD 71, 071103(R) X(3872) hep-ex/0406022

  16. Is it a cc meson? Could it be one of these? 3872 MeV These states are already identified

  17. no obvious cc assignment hc” hc’ cc1’ y2 hc2 y3 M too low and G too small angular dist’n rules out 1+- 3872 G(gJ/y) way too small G(gcc1) too small;M(p+p-) wrong pp hc should dominate G( gcc2 & DD) too small SLO hep-ex/0407033

  18. go back to square 1 Determine JPC quantum numbers of the X(3872) with minimal assumptions

  19. JPC possibilities (for J ≤ 2)

  20. JPC possibilities0-- ruled out; JP=0+,1- & 2+ unlikely

  21. Areas of investigation • Search for radiative decays • Angular correlations in XppJ/y decays • Fits to the M(pp) distribution • Search for X(3872)D0D0p0

  22. Search for X(3872)g J/y

  23. Kinematic variables BK gJ/y Ecm/2 e+ e- B B ϒ(4S) Ecm/2 DE CM energy difference: BK gJ/y Beam-constrained mass: Mbc

  24. Select BKg J/y BKcc1; cc1g J/y X(3872)? M(gJ/y) Mbc Mbc 13.6 ± 4.4 X(3872)gJ/y evts (>4s significance) Bf(XgJ/y) Bf(XppJ/y) =0.14 ± 0.05

  25. Evidence for X(3872)p+p-p0 J/y(reported last summer hep-ex/0408116) B-meson yields vs M(p+p-p0) A virtual w(782)? M(p+p-p0) MeV 12.4 ± 4.2 evts Br(X3pJ/y) Br(X2pJ/y) Large (near max) Isospin violation!! = 1.0 ± 0.5

  26. C=+1 is established • Xg J/y only allowed for C=+1 • same for X”w”J/y (reported earlier) • M(pp) for Xp+p-J/y looks like a r CDF

  27. JPC possibilities (C=-1 ruled out)

  28. Angular Correlations J/y Jz=0 J=0 X3872 J=0 K z Rosner (PRD 70 094023) Bugg (PRD 71 016006) Suzuki, Pakvasa (PLB 579 67) pp

  29. Use 253 fb-1  ~275M BB prsexploit the excellent S/N X(3872)p+p-J/y y’p+p-J/y Signal (47 ev) Sidebands (114/10 = 11.4 ev)

  30. Example: 1-- J/y y’ Use BK y’ K z y’is 1-- dN/dcosq  sin2qKm pp y’: c2/dof = 8.9/9 qKm K compute angles in J/y restframe D.V. Bugg hep-ph/0410168v2

  31. |cosqKl| for X(3872) events c2/dof = 60.3/9 fit with sin2qKl + bkgd see 8 evts/bin expect 2~3evts/bin background scaled from sidebands X(3872) is not 1-- !

  32. 0++ M eJ/y·er In the limit where X(3872), pp, & J/y rest frames coincide: dN/dcosqlp sin2qlp qlp c2/dof = 34/9 rule out 0++ |cosqlp|

  33. 0-+ M  pJ/y· (eJ/yxer) c2/dof=18/9 0-+ : sin2q sin2y q |cosq| c2/dof=34/9 y |cosy| safe to rule out 0-+

  34. 1++ M | eX xeJ/yxer| dN/dcosqdcosc sin2ql sin2c c2/dof = 11/9 ql K |cosql| c c2/dof = 5/9 1++ looks okay! |cosc| compute angles in X(3872) restframe

  35. JPC possibilities (0-+ & 0++ ruled out)

  36. Fits to the M(pp)Distribution J/y XrJ/y has a q*(2l+1) centrifugal barrier q* X q* r

  37. M(pp) can distinguish r-J/y S- & P-waves P-wave: c2/dof = 71/39 S-wave: c2/dof = 43/39 (CL=0.1%) (CL= 28%) q* roll-off q*3 roll-off Shape of M(pp) distribution near the kinematic limit favors S-wave

  38. Possible JPC values (J-+ ruled out)

  39. X(3872)D0D0p0?

  40. Select BKD0D0p0 events D*0D0p0? M(D0D0p0) 11.3±3.6 sig.evts (5.6s) Bf(BKX)Bf(XDDp)=2.2±0.7±0.4x10-4 Preliminary |DE| |DE|

  41. X(3872)DDp rules out 2++ • 1++ : DD* in an S-wave  q* • 2++ : DDp in a D-wave  q*5 Strong threshold suppression

  42. Eliminate all other factors and the one which remains must be the truth Sherlock HolmesThe Sign of Four

  43. Possible JPC values (2++ ruled out) 1++ 1++

  44. can it be a 1++ cc state? 1++ cc1’ • Mass is ~100 MeV off • cc1’  r J/y not allowed by isospin. Expect: Bf(cc1’ppJ/y)<0.1% BaBar measurement: Bf(XppJ/y)>4% 3872 -G(cc1’gJ/y) / G(cc1’ppJ/y) Expect: ~ 40 cc1’ component of X(3872) is ≤ few% • G(X3872gJ/y) / G(X3872ppJ/y) • Measure: 0.14 ± 0.05

  45. From BaBar: D(*)p+ e+e-B+B- K-X0 fully reconstructed Jon Coleman Moriond-QCD March 2005 244 fb-1 • Can measure absolute B.F.’s of B-K-X0 J/y Lower limit on BF(XJ/ypp) > 4.3% @ 90% C.L cc2 cc1 cc0 Very clear J/y and hc signals N J/y=258+- 42 N hc =266 +-42 • cc2,cc0<<cc1 • X(3872) production much lower than for other Charmonium states: • can set lower limit on B.F.

  46. Intriguing fact lowest mass charmed meson MX3872 =3872 ± 0.6 ± 0.5 MeV mD0 + m D0* = 3871.2 ± 1.0 MeV lowest mass spin=1 charmed meson X(3872) is very near DD* threshold. is it somehow related to that?

  47. D0D*0 bound state (deuson)? Voloshin & Okun JETP Lett 23, 333 (1976) Bander et al PRL 36, 695(1976) DeRujula et al PRL 38, 317 (1977) Manohar & Wise, NP B339, 17 (1993) Tornqvist, Z Phys C61, 525(1994) Tornqvist hep-ph/0308277 deuteron: deuson: attractive nuclear force attractive force?? c c p n D p D* p u u 2 loosely bound qqq color singlets with Md = mp+mn- e 2 loosely bound qq color singlets with M= mD + mD* - d

  48. X(3872) = D0D*0 bound state? • JPC = 1++ is favored • M ≈ mD0 + mD0* • Maximal isospin violation is natural (& was predicted): |I=1; Iz= 0> =1/2(|D+D*->+ |D0D*0>) |I=0; Iz= 0> =1/2(|D+D*-> - |D0D*0>)  |D0D*0> = 1/2(|10> - |00>) • G(XgJ/y) < G(XppJ/y) was predicted Tornqvist PLB 590, 209 (2004) Equal mixture of I=1 & I =0 Swanson PLB 588, 189 (2004) Swanson PLB 598, 197 (2004)

  49. X(3872) conclusion • JPC = 1++ • cc content is small • matches all(?) expectations for a D0D*0 bound state C C u c u c a non-qq meson

  50. Are there others?Is the X(3872) a one-of-a-kind curiousity? or the 1st entry in a new spectroscopy? Look at other B decays  hadrons+J/y: BK h J/y BK p J/y BK w J/y

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