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New Hadron Results from the B Factories

New Hadron Results from the B Factories. Brian Meadows University of Cincinnati. B Factory Luminosities. Peak luminosity 1.00 10 34 cm –2 s –1 Integrated luminosity 299 fb –1. Peak luminosity 1.58 10 34 cm –2 s –1 Integrated luminosity 488 fb –1. e + e - (3.1 x 9.0 GeV/c).

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New Hadron Results from the B Factories

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  1. New Hadron Results from the B Factories Brian Meadows University of Cincinnati Brian Meadows, U. Cincinnati.

  2. B Factory Luminosities Peak luminosity 1.001034 cm–2s–1 Integrated luminosity 299 fb–1 Peak luminosity 1.581034 cm–2s–1 Integrated luminosity 488 fb–1 e+ e- (3.1 x 9.0 GeV/c) e+ e- (3.5 x 8.0 GeV/c) 1 fb-1 ~1.1M BB events Brian Meadows, U. Cincinnati

  3. BaBar and Belle e+ (3.5 GeV/c) e- (8 GeV/c) • Main purpose: Study CP violation in asymmetric e+e- (4S)  BB • A major difference between the two detectors is the PID system: • Babar: Dirc ring imaging C • Belle: TOF and Threshold C with aerogel v v Brian Meadows, U. Cincinnati

  4. Hadrons - Friends or Foes? • Hadrons may get in the way of the “really interesting” quark and lepton interactions, but they can also aid in understanding them … … for example, in finding the CKM angles … Brian Meadows, U. Cincinnati

  5. PRD 71: 032005 (2005) 89 fb-1 CKM Angle  and Hadrons • To measure sin 2β - the golden channel is B0 J/Ks • Leads to a four-fold ambiguity in the determination of the angle β. • Babar used B 0 J/K-+ to find sign of cos 2 • An amplitude analysis was made of the K-+ system to determine the relative phase between S- and P-wave contributions to the decay • A clear choice agrees with the LASS data Brian Meadows, U. Cincinnati

  6. M 2+ M 2+ M 2- M 2- CKM Angle g from Direct CP Violationin B§D 0K§ =rb ei ( B§ )x § K0+- § § K0+- § f(m2- ,m2+ ) f(m2+ ,m2- ) • Angle  relates the two decays B- D 0K-andB-  D 0K- • WhenD0(D 0) K-(K 0) +- • If CP conserved in D0 decay, Dalitz plot for D0 is identical except that+  - • Thefinal states are indistinguishable  The two Dalitz plots interfere f(m2+ ,m2- ) + rbe i(B§)f(m2- ,m2+ )  (, rb, B) Brian Meadows, U. Cincinnati

  7. PRL 95: 121802 (2005) and hep-ex/0504039 205 fb-1 D0 K0+- Dalitz Plot Analysis • Use large available sample of D0 from e+e-cc continuum to determine the Dalitz plot density for D 0 • Two models used: • “Breit-Wigner Isobar model” Requires 13 resonances including “(500)” and “(1000)” • K-matrix model (fit shown) better way to describe the  S-wave – no ’s needed Brian Meadows, U. Cincinnati

  8. New DsJ Mesons A New Form of Matter? Brian Meadows, U. Cincinnati

  9. SQ L Sq Heavy-Light Systems areSomewhat Like the Hydrogen Atom • When mQ ! 1, sQ is fixed. • So jq = L­sq is separately conserved • Total spin J = jq­sQ • Ground state (L=0) is doublet with jq=1/2 • Orbital excitations (L>0) – two doublets (jq=l+1/2 and jq=l-1/2). • For decays to ground state (L=1)! (L=0) +  : • for jq=3/2 state, final hadrons are in orbital D wave !jq= 3/2 states are narrow. • for decay of DJ(jq=1/2) state, final hadrons are in orbital S wave !jq=1/2 states are expected to be broad. Brian Meadows, U. Cincinnati

  10. Heavy-Light Systems (2) 2jqLJ  JP • Narrow statesare easy to find. • Two wide states are harder. • Since charm quark is not infinitely heavy, some jq=1/2, 3/2 mixing can occur for the JP=1+ states. jq = 3/2 2+ small 3P2 large 1+ 1P1 L = 1 1+ 3P1 small jq = 1/2 1P0 0+ large tensor spin-orbit jq = 1/2 1- small 1S1 L = 0 small 0- 1S0 Brian Meadows, U. Cincinnati

  11. Charmed Meson Spectroscopy • This picture worked well prior to 2003 with all narrow L=0 and L=1 states found by 1995. • The wide, nonstrangejl=1/2 states were found in B decays by CLEO (1999) and BELLE (2002). Subsequently confirmed by BABAR in 2003. • Most potential model calculations had correctly predicted masses above threshold for  emission for these states, with broad widths. BUT they also • Generally agreed that strange jl=1/2 states 1Ds0,1Ds1 would be above threshold for K emission. Brian Meadows, U. Cincinnati

  12. Charmed Meson Spectroscopy c. 1995 Brian Meadows, U. Cincinnati

  13. Charmed Meson Spectroscopy pre 2003 D*0K+threshold D0K+threshold BABAR may have found these – but below threshold. Brian Meadows, U. Cincinnati

  14. Search for Ds Mesons by BaBar in 2003 • All pairs of ’s, each  having energy > 100 MeV, are fitted to a 0 with mass constraint. • Each 0 is fitted twice: • To the production vertex to investigate the Ds+0 mass. • To the K+K-+ vertex so that we can also use the Ds!K+K-+0 mode. D’s from B decays were removed: - each event was required to have pD* > 2.5 GeV/c Results from B decays are also in the literature now. Brian Meadows, U. Cincinnati

  15. K+K-+ Mass Spectrum Approx. 131,000 Ds+ events above large background. 4 3 2 1 0 X 103 X 103 60 40 20 0 D0! K+K- Events / 3 MeV/c2 1.75 1.85 1.95 m(K-K+) GeV/c2 1.8 1.9 2.0 m(K-K++) GeV/c2 Small bump at 2010 MeV/c2 from Brian Meadows, U. Cincinnati

  16. The Ds+ Dalitz Plot • Data sample: D*s(2112)+!Ds+: • NOTE • K* and  bands do not cross (no double counting). • cos2 distributions evident in vector bands. Selection essentially keeps events in the 4 peaks. Brian Meadows, U. Cincinnati

  17. Total K+K-+ Mass Spectrum • Sum of + and K¤*0K+ contributions is » 80,000 Ds+ above background. • We define signal region: 1954 < m(K+K-+) < 1980 MeV/c2 and two sideband regions: 1912 < m(K+K-+) < 1934 MeV/c2 1998 < m(K+K-+) < 2020 MeV/c2 Brian Meadows, U. Cincinnati

  18. The Ds(2317) and Ds(2460)see PRL 90, 242001 (2003) • When BaBar studied the Ds0 system he found a huge, unexpected peak. CLEO had discarded All these events. How did CLEO miss it?! Brian Meadows, U. Cincinnati

  19. Brief Summary (so far) • Real and it decays to Ds+0: Implies natural parity. • Narrow - consistent with BaBar resolution :  < 10MeV/c2. • If a normal Ds+ then this decay violates I - spin conservation. • This could explain the narrowness. • Mass below D0K+ threshold may force such a decay. JP = (-1)Lh1h2 = (-1)L Has a problem decaying! Brian Meadows, U. Cincinnati

  20. What Could it Be? • Could be the missing J P=0 + BUT if so, its mass is lower by » 170 MeV/c2 than expected by potential models. We label it “DsJ*(2317)+” • Could this be an “Exotic Meson”: • Four quark state –csuu, csud, csdd • DKbound state? • If exotic, should have I - spin partners. Brian Meadows, U. Cincinnati

  21. DsJ(2317) ? DsJ(2460) ? Ds+p- 232fb-1hep-ex/0604030 Ds+p+ DsJ’s - Overtly Exotic ? • No indication of overtly exotic charged states Circles are Ds side-bands • ForDsJ(2460) need to look inDs(*)+0+,-if J P= 1+ Brian Meadows, U. Cincinnati

  22. Search for Other DsJ+(2317) Decay Modes • We have studied the mass spectra for • Ds+0 0 • Ds+ • Ds+  • Ds*+(2112) • Ds+0  • In all cases, we require that: • The ’s are not part of any 0 candidate. • The combination has p* > 3.5 GeV/c. None of these found Brian Meadows, U. Cincinnati

  23. Ds+0, Ds*(2112)0- Other Possibilities No evidence for D*sJ(2317)+ either of these modes BUT … Events / 7 MeV/c2 Ds*(2112)0 See yet another state at ~ 2460 MeV/c2 !! m(Ds+0) Also seen in other modes …… Brian Meadows, U. Cincinnati

  24. 125 fb-1 hep-ex/0408067 Ds+(2460)  Ds+ p*(Ds+) > 3.2 GeV/c E > 500 MeV Clear peak from DsJ(2460)+ DsJ(2460)+: 509  46 events Mass: 2457.2  1.6  1.3 MeV/c2 DsJ(2460)+ Ds*(2112)+ Ds+ Reflection Background subtracted Ds+  invariant mass (GeV/c2) Compatible with DsJ*(2317)+ JP =0+ Excludes JP=0+ for Ds*(2460)+ Brian Meadows, U. Cincinnati

  25. 125 fb-1 hep-ex/0408067 Ds+(2460)  Ds++ - p() > 250 MeV/c Ds1(2536)+ Clear peaks for both JP=1+ candidates: DsJ(2460)+andDs1(2536)+ DsJ(2460)+ DsJ(2460)+: 67  11 events Mass: 2460.1  0.3  1.2 MeV/c2 Ds+ + - invariant mass (GeV/c2) I-spin conserved BUT OZI suppressed Forbidden for DsJ*(2317)+ JP =0+ Excludes JP=0+ for Ds*(2460)+ Brian Meadows, U. Cincinnati

  26. Penta-Quarks A New Form of Matter ? Brian Meadows, U. Cincinnati

  27. Baryons with 3 Quarks • They must belong to {1}, {8} or {10} • Limits on possible Flavour/Charge combinations are possible. • For example, S=+1 is impossible ! • If S = -2 (two s quarks with Q=-2/3) then Q=0 or Q=–1 • If C = 1 (one c quark) then …. Brian Meadows, U. Cincinnati

  28. S = +1 Baryon +(1540) ? CLAS I Experiment Brian Meadows, U. Cincinnati

  29. S = +1 Baryon +(1540) ? CLAS II Experiment Brian Meadows, U. Cincinnati

  30. S = +1 Baryon +(1540) ? CLAS II Experiment Brian Meadows, U. Cincinnati

  31. S = -2 Penta-Quark ? Brian Meadows, U. Cincinnati

  32. Charm Penta-Quark ? • Seen in one experiment at DESY (Hamburg, Germany) • Not confirmed by other DESY experiment (ZEUS) Brian Meadows, U. Cincinnati

  33. Penta-Quark Models Possibility of Quark “Molecules” Brian Meadows, U. Cincinnati

  34. Fixed Target Experiments Too?Penta-Quark Searches BaBar Belle e-NK 0p Vertices • hep-ex/0507014: • (1540)/(1520) < 2.5% (90% CL) No (1540) pentaquark signal seen: Preliminary e- Be e- Be M (K0p) (GeV/c2) M (K0p) (GeV/c2) Brian Meadows, U. Cincinnati

  35. hep-ex/0408064 & 0502004 123 fb-1 BaBar Pentaquark Searches • No signal for 5(1540) • No signal for --(1860) • Pentaquark signals at least factor four below ordinary baryon production in e+e- annihilations Brian Meadows, U. Cincinnati

  36. Charm Baryons Brian Meadows, U. Cincinnati

  37. JP=1/2+ (L=0) JP=3/2+(L=0) Charm Isospin Strangeness JP=1/2+ (L=0) Charm Baryon States BUT - No JP are yet measured ! • |C| = 1: • L=0 Ground State – almost full: JP=1/2+: {6}qqSc(2455), Xc(2470), Wc(2698) All seen JP=1/2+: {3}qqLc(2285), X0c(2575) All seen JP=3/2+: {6}qqLc(2285), X0c(2575), ?? All but Wc* • L>1 – filling up ? JP=1/2-: – Lc(2593), Xc(2790), … JP=3/2-: – Lc(2625), Xc(2815), … • Several more new states from BaBar and Belle … and more … from CLEO 2 (or )c(2880), (or )c (2765) ?? Brian Meadows, U. Cincinnati

  38. Last Ground State Charm Baryon (2006) -+ • Theory expects c* (JP=3/2+) to be ~70 MeV/c2 above c (JP=1/2+) • We look for events like: e+ e- c0*  c0 • Several ways to look for c0 itself: c0  -+   -+ 0   -+ + - +   -K - + + -+0 -+-+  -  K-  p - -K-++  -  K-  p - All M = M (c*) – M (c) = 70.8 § 1.0 (stat) § 1.1 (syst) MeV/c2 Brian Meadows, U. Cincinnati

  39. 287fb-1hep-ex/0603052 First Charm Baryon  Charm MesonLc(2940) • Observed in cc continuum production inD0pdecay mode(D0 K-p+, K-p+p-p+) Λc(2940)+ : M = (2939.8±1.3±1.0) MeV/c2 Γ = (17.5±5.2±5.9) MeV Λc(2880)+ Λc(2940)+ New data on Λc(2880)+ : New Decay Mode D0p BaBar: M = (2881.9±0.1±0.5) MeV/c2 Γ = (5.8±1.5±1.1) MeV PDG: (“Could be Sc”) M = (2880.9±2.3) MeV/c2 ; Γ < 8 MeV Wrong sign D0p D0 mass sidebands Brian Meadows, U. Cincinnati

  40. 287fb-1hep-ex/0603052 New Baryon Lc(2940) • Neither Lc(2940) nor Lc(2880) seen in D+p system  Neither are Sc’s • Other observations: • Why not seen in Lcp+p- or Scp? • Three states predicted near this mass3/2-, ½+, ½- • Lc(2940) is 6 MeV/c2 belowD*pthreshold • Lc(2940) ispmass aboveLc(2880) c++’s ?? Brian Meadows, U. Cincinnati

  41. Phys.Lett.B628:18-24,2005 SELEX Search for cc States • Predicted in mass range 3.5 – 3.8 GeV/c2 • Predicted cross-sections from e+e- @ 10 GeV/c2 ~ 1-250 fb Double-charm cross-sections under-estimated by NRQCD  expect to produce 102 – 104 from 232 fb-1 SELEXreports state at 3.52 GeV/c2 - beam ~ 1,630 +c Not confirmed by FOCUS beam ~ 19,500 +c Nor BaBar, nor Belle e+e- ~ 106c+ Brian Meadows, U. Cincinnati

  42. Λc+K–π+ p*> 0 GeV/c 232fb-1hep-ex/0605075 Λc+K–π+ p*>2.3 GeV/c Λc+K–π+π+ p*> 0 GeV/c Λc+K–π+π+ p*>2.3 GeV/c Search for cc States cc+(+)c+K-+(+) Search made throughout ranges indicated • for both charge states, • with and without p*cuts 21 two-d fits: Gaussian signal on background in overlapping 10 MeV/c2 ranges. Results normalized to cross-section for producing c+ 95% C.L. limits: Brian Meadows, U. Cincinnati

  43. Ξc0π+ p*> 0 GeV/c 232fb-1hep-ex/0605075 Ξc0π+ p*> 2 GeV/c Ξc0π+π+p*> 0 GeV/c Ξc0π+π+p*> 2 GeV/c Search for cc States 95% C.L. limits: c c+(+)Xc0+(+) Search made throughout ranges indicated 50 fits: Double Gaussian signal on linear background in 10 MeV/c2 ranges. Results compare with Brian Meadows, U. Cincinnati

  44. 462 fb-1PRELIMINARY Search for Xcc States • Belle also found no evidence for the state seen by SELEX using an even larger sample. M(Lc+K-p+) (GeV/c2) Brian Meadows, U. Cincinnati

  45. 462 fb-1 462 fb-1PRELIMINARY Observation of Two New Xc(csu)States in cc Continuum Production • While searching for weak decay of • Xcc Lc+K- p+ •  pK-p+ • Found strong decays of new Xc* ‘s instead: • Xcx Lc+K- p+ No structure in Lc+ sidebands Nor in Lc+K+p- or Lc+K-p- wrong sign combinations. Brian Meadows, U. Cincinnati

  46. PRL 94, 122002, 2005 350 fb-1 p Observation of New Sc Triplet Tentative assignment to JP = 3/2 - Brian Meadows, U. Cincinnati

  47. Baryon Spin Measurements Brian Meadows, U. Cincinnati

  48. Xc0W-K+ 116 fb-1 Preliminary 230 fb-1 Preliminary Wc0W-p+ The Spin of The W- • The existence of large samples of charm baryons makes possible what was once incredibly difficult ! Earlier results from bubble chambers using small, unaligned samples of W- could only conclude that J>1/2. Assume the spin of charmed parent is ½: In the charm hyperon rest frame, the W- is produced with helicity § ½ independent of the W- spin J. Brian Meadows, U. Cincinnati

  49. 230 fb-1 Preliminary 116 fb-1 Preliminary Xc0W-K+ Wc0W-p+ J = 1/2 J = 3/2 J = 3/2 J = 5/2 The Spin of The W- • The W-L K - decay distribution in its “helicity frame” is then  Conclude J = 3/2 (if charmed parents are J=1/2). Brian Meadows, U. Cincinnati

  50. 357 fb-1hep-ex/0510074 (2005) How About Charm Baryons? • Information on charm baryon spins could come from decays like B+,0c0,-c+  -+ • So far (Belle 357 fb-1) only ~12 events where c0 -+  Not promising for determination of J Brian Meadows, U. Cincinnati

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