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New types of sub-atomic particles

New types of sub-atomic particles. Stephen L. Olsen University of Hawai’i. d. u. u. d. s. u. c. u. c. c. c. History: (hadrons). chadwick. 1930’s: proton & neutron ..all we need??? 1950’s: ,,,,,… “Had I foreseen that, I would have gone into botany” – Fermi

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New types of sub-atomic particles

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  1. New types of sub-atomic particles Stephen L. Olsen University of Hawai’i d u u d s u c u c c c

  2. History:(hadrons) chadwick 1930’s: proton & neutron ..all we need??? 1950’s: ,,,,,… “Had I foreseen that, I would have gone into botany” – Fermi 1960’s: The 8-fold way “3 quarks for Müster Mark” 1970’s add charmed particles 1980’s & beauty 1990’s & (finally?) top Fermi Gell-Mann Zweig Richter Ting Lederman Peters Jones

  3. Hadron “zoo” mesons baryons

  4. Quarks restore economy(& rescue future Fermis from Botany?) 3 quarks (& 3 antiquarks) u+2/3 u-2/3 M. Gell-Mann d-1/3 s-1/3 d+1/3 s+1/3 Baryons: qqq Mesons: q q Zweig u+2/3 u+2/3 p: u+2/3 d-1/3 p+: d+1//3 u-2/3 u-2/3 u-2/3 p: p-: d+1/3 u+2/3

  5. Fabulously successful, but… • quarks are not seen • why only qqq and qq combinations? • What about spin-statistics?

  6. W- s-1/3 s-1/3 s-1/3 2 of these s-quarks are in the same quantum state Das ist verboten!!

  7. The strong interaction “charge” of each quark comes in 3 different varieties Y. Nambu O. Greenberg W- s-1/3 s-1/3 s-1/3 the 3 s-1/3 quarks in the W- have different color charges & evade Pauli

  8. QCD: Gauge theory for color charges Nambu Gell-Mann & Fritzsch generalization of QED QED QCD er eb eg scalar charge: e isovector charge: QED gauge Xform QCD gauge Xform   + ie A   + i ali Gi 1 vector field (photon) 8 vector fields (gluons) eight 3x3 SU(3) matrices

  9. Attractive configurations eijkeiejek i ≠ j ≠ k dijei ej same as the rules for combining colors to get white: add 3 primary colorsoradd color+complementary color quarks: eiejek color charges antiquarks: anticolor charges ei ej ek Hence the name: Quantum Chromodynamics

  10. Difference between QED & QCD QED: photons have no charge QCD: gluons carry color charges gluons interact with each other

  11. QEDQCD difference Coupling strength a distance

  12. Test QCD with 3-jet events(& deep inelastic scattering) as gluon rate for 3-jet events should decrease with Ecm

  13. “running” as Why are these people smiling?

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

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

  16. Experimental situation is messy(many contradictory results) NA49 pp @ Ecm=17 GeV (fixed tgt) (PRL92, 052301: 237+ citations!) COMPASS mp @ Em =160 GeV (fixed tgt) X(1862): qqssd 1862 ± 2 MeV FWHM = 17 MeV  = 5.6 100sof X(1530)s but no hint of X(1862) hep-ex/0503033

  17. Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L3 Yes: 17 No: 17

  18. Existence of Pentaquarksis not yet established

  19. This talk: search for 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

  20. Thanks to KEKB we have lots of B mesons(>1M BB pairs/day) >1fb -1/day Design: 10 34

  21. Is the X(3872) non-standard? BK p+p-J/y y’p+p-J/y X(3872)p+p-J/y S.K. Choi et al PRL 91, 262001 M(ppJ/y)

  22. Its existence is well establishedseen in 4 experiments CDF 9.4s 11.6s X(3872) D0 X(3872) hep-ex/0406022

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

  24. 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

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

  26. JPC possibilities (for J ≤ 2)

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

  28. 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

  29. Search for X(3872)g J/y

  30. 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

  31. 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 (>5s significance) Bf(XgJ/y) Bf(XppJ/y) =0.14 ± 0.05

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

  33. C=+1 is established • B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

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

  35. Angular Correlations r Jz=0 J=0 X3872 J=0 K z J/y

  36. Strategy: for each JPC, find a distrib 0if we see any events there, we can rule it out Rosner (PRD 70 094023) Bugg (PRD 71 016006) Suzuki, Pakvasa (PLB 579 67)

  37. Use 250 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)

  38. 0-+ c2/dof=18/9 0-+ : sin2q sin2y q |cosq| c2/dof=34/9 y |cosy| safe to rule out 0-+

  39. 0++ In the limit where X(3872), pp, & J/y rest frames coincide: dG/dcosqlp sin2qlp qlp c2/dof = 41/9 |cosqlp| rule out 0++

  40. 1++ compute angles in X(3872) restframe 1++: sin2ql sin2c c2/dof = 11/9 ql K |cosql| c2/dof = 5/9 c |cosc| 1++ looks okay!

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

  42. Fits to the M(pp)Distribution J/y XrJ/y in P-wave has a q*3 centrifugal barrier q* X r q*

  43. 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

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

  45. Search for XD0D0p0

  46. 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|

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

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

  49. 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) Theory: ~ 40 Expt: 0.14 ± 0.05 cc1’ component of the X(3872) is ≤ few %

  50. 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?

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