2006/3/ /3/25 Moriond QCD 1 B -> Baryon decays in Belle Sheng-Wen Lin National Taiwan University

S.-W. Lin 2006/3/19 Moriond QCD 2 Introduction B meson can decay into baryonic final states due to its heavy mass, through b-> cW, b-> uW and b-> s gamma … There are several theoretical models to predict BRs. Topics 1.BR. Measurements for charmless and charmed decays 1.BR. Measurements for charmless and charmed decays New baryonic B decays through b-> s gamma and b->c(cs) New baryonic B decays through b-> s gamma and b->c(cs) 2.Low mass enhancements in 3-body charmless baryonic decays 2.Low mass enhancements in 3-body charmless baryonic decays Decay angle distribution  fragmentation picture Decay angle distribution  fragmentation picture 3.Glueball search 3.Glueball search 4.Study of J/ψ  pp and ΛΛin B  J/ψK decay 4.Study of J/ψ  pp and ΛΛin B  J/ψK decay 5.Intermediate states 5.Intermediate states Observation only in the charmed baryonic decays Observation only in the charmed baryonic decays

S.-W. Lin 2006/3/19 Moriond QCD 3 Status of charmless baryonic B decays HFAG uud dss suu uud suu sdd ss sss 2-body 3-body UL updated

S.-W. Lin 2006/3/19 Moriond QCD 4 B +  pΛγ PRL 95, , 2005 Simultaneous fit to B  pΛγ and B  pΣ 0 γ Signal Yield for B  pΛγ with M p Λ <2.4GeV/c 2 : 34.1 Statistical Significance: 8.6σ BF(B  pΛγ ): 2.16 ± 0.20x10 -6 BF( B  pΣ 0 γ ):<4.6 x fb -1 pΛγSignal ΔE=E B -E beam M bc =(E beam 2 -P B 2 ) 1/2

S.-W. Lin 2006/3/19 Moriond QCD 5 Angular distribution Fit results in bins of cosθ X with M pΛ <4.0GeV/c 2 (Assuming X  pΛ, calculated in X rest frame.) qq background Signal Yield X frame Λ γ p θxθx A=(N+/N-)/(N+-N-)= Short-distance b  sγ

S.-W. Lin 2006/3/19 Moriond QCD 6 Threshold Enhancements in b->s and b-> u modes PLB 617, , 2005 ppK + ppK 0 S p  - 140fb -1

S.-W. Lin 2006/3/19 Moriond QCD 7 Angular distribution: ppK + (b->s mode) b  s dominant process Fragmentation picture u s uud duu u s K+K+ pp p p K+K+ ӨpӨp X ppK signal in pp rest frame

S.-W. Lin 2006/3/19 Moriond QCD 8 Angular distribution: pΛ π - (b->u mode) π-π- Λ p ӨpӨp X in pΛ rest frame Λ p π-π- ӨpӨp X in p π - rest frame Fragmentation picture

S.-W. Lin 2006/3/19 Moriond QCD 9 Glueball Search in B->K p p The theoretician suggest a possible glueball resonance with mass around 2.3GeV/c 2 (PLB 544, 139, 2002) Scanning the mass region from 2.2 to 2.4 GeV/c 2 No significant signal is found. We set a 90% confidence-level upper limit: BF(B +  glueball K + ) x BF( glueball  pp) < 4.1x10 -7

S.-W. Lin 2006/3/19 Moriond QCD 10 J/Ψ helicity angle definition In general, the angular distribution of J/Ψ baryon anti- baryon pair can be written as θ : helicity angle α : constant J/Ψ momentum direction θ baryon anti-baryon

S.-W. Lin 2006/3/19 Moriond QCD 11 J / Ψ → p p helicity angle distribution ※ Efficiency corrected Likelihood fit 357fb -1

S.-W. Lin 2006/3/19 Moriond QCD 12 First observation of η c → ΛΛ Significance = 8.1σ Yield = 19.5 BR (ηc->ΛΛ) = 0.87 (stat.) (syst.) ±0.27(PDG)x

S.-W. Lin 2006/3/19 Moriond QCD 13 ccs Br=10% Br=1% cud 2-body 3-body 4-body 3-body 2-body Status of charmed baryonic B decays

S.-W. Lin 2006/3/19 Moriond QCD 14 B+  c c+B+  c c+ Br  a few if Br(  c 0   -  + ) ~ 1% ( NP B345 (97) 137 ) Large Br as 2-body decay (4.8 ±1.1±1.2)x Br(B +   c 0  c + )x Br(  c 0   +  - ) = B +/0   c 0  c +  0/-, B 0/+   c 0  c 0/+,  c 0/+   c +  -/0 bkgnd 8.7  29 evnts M(  c 0 ) M(  c + ) 357fb -1 Br(B 0   c + p) =(2.19 ±0.32±0.57)x10 -5 PRL90(03)

S.-W. Lin 2006/3/19 Moriond QCD 15 B0  c c+B0  c c+ ( 9.3 ±1.9±2.2 )x Br(B 0   c -  c + )x Br(  c +   -  +  + ) = Br ~ a few if Br(  c +   -  +  + ) ~ 1%. Br(B 0   c + p) =(2.19 ±0.32±0.57)x10 -5 PRL90(03) evnts 3.8  M(  c - ) M(  c + ) 357fb -1

S.-W. Lin 2006/3/19 Moriond QCD 16 B -  J/   p 17.2±4.1 events 11.1  Mbc  M B =M rec (B)-M B MBMB Br( B -  J/   p ) = Br( B -  J/    p ) Br( B 0  J/  p p ) < 1.1x10 -5 < 8.3x10 -7 UL at 90% CL 11.6 ±2.8(stat) (sys) x body invariant masses 253fb -1

S.-W. Lin 2006/3/19 Moriond QCD 17 B -   c   c + K - Br=(6.5 ±0.8±3.4)x events 15.4   c -  c +) M(  c - )M(  c + ) 357fb -1

S.-W. Lin 2006/3/19 Moriond QCD 18 B 0   c   c + K 0 Br=(7.9 ±1.2±4.2)x  c -  c +) hep-ex/ M(  c - )M(  c + ) 10.5 evts 6.6  357fb -1

S.-W. Lin 2006/3/19 Moriond QCD 19 Summary BF(2-body) < BF(3-body) Low mass enhancement of di-baryon and decay angle distribution supports fragmentation picture Observation of B + pΛγ(b -> sγ mode) Charmless baryonic decays : Charm baryonic decays : BF(2-body) < BF(3-body) < BF(4-body) Observation of double charmed decays