Baryon Production and Pentaquark Searches at B Factories B.Mellado (University of Wisconsin-Madison) For the BaBar and Belle Collaborations FPCP04, Daegu, Rep. of Korea 10/08/04

Outline Introduction Charmless B decays into baryons Branching Fraction measurements Searches for the + and ++ pentaquarks Inclusive searches in e+e- for strange pentaquarks B decays into Baryons involving charm Search for charmed pentaquarks Structure in M(c+p) spectrum Studies of charmed Baryons (not covered) Belle-CONF-0463, BaBar-CONF-04/04, BaBar-CONF-04/22 Outlook and Conclusions Bruce Mellado, FPCP04 10/08/04

Baryon Production in B Decays Little is understood in Baryon production in B decays Significant input from data in recent years A lot of progress due to B factories BBaryons not saturated by BcX Dominance of multi-body final states Βr(B2body)<Βr(B3body)<Βr(B4body) Baryon-Antibaryon enhancements? Exotic states? Enhancements? Exotic states? ? Pentaquarks? Bruce Mellado, FPCP04 10/08/04

Pentaquark Searches Triggered by a prediction (Diakonov et al. Z.Phys. A359 (1997) 305-314) narrow peak in K+n invariant mass was observed M.Karliner Moriond04 Discovery of + (S=+1, uudds) has created a lot of excitement NA49 gave evidence of -- (S=-2, dsdsu, 1.862 GeV) H1 gave evidence of charmed c0 (ududc, 3.1 GeV) A number of experiments have reported negative results Bruce Mellado, FPCP04 10/08/04

Pentaquark Searches (cont) B-Factories is at (4S) threshold BB - Continuum Y (4S) B factories are also produce copiously u d s c quarks Additional production mechanisms in inclusive searches Bruce Mellado, FPCP04 10/08/04

KEKB/Belle Performance KEKB peak luminosity: 1.39 x 1034 sec-1cm-2 @ 1.2A x 1.6A 253 fb-1 on Y(4S) 28 fb-1 below Y(4S) 281 fb-1 3.5 GeV e+ 8 GeV e- Bruce Mellado, FPCP04 10/08/04

PEP-II/BaBar Performance PEP-II top luminosity: 9.2 x 1033cm-2s-1 221 fb-1 on Y(4S) 23 fb-1 below Y(4S) 244 fb-1 Run1 Run2 Run3 Run4 3.1 GeV e+ 9 GeV e- Bruce Mellado, FPCP04 10/08/04

B Signal Reconstruction In Υ(4S) rest frame: ∆E B Υ(4S) e- e- e+ e+ B MES Bruce Mellado, FPCP04 10/08/04

Searches for Strange pentaquarks B Charmless Decays Searches for Strange pentaquarks Bruce Mellado, FPCP04 10/08/04

First Observation of B+ΛΛK+ First charmless B decay with ΛΛ with 7.4  significance Probes the decay bsss Complementary to BφK(*) Threshold enhancement of ΛΛ 140 fb-1 Threshold enhancement Phase Space MC Bruce Mellado, FPCP04 10/08/04

Search for B+ΛΛ+ No evidence found with 140 fb-1 90% Confidence level set # of background 37.51, # of observed events 41 PRL92 131801, 2004 Bruce Mellado, FPCP04 10/08/04

First Observation of B+pΛ Preliminary Simultaneous fit on B+pΛ and B+p0 Signal yield for BpΛ with MpΛ<2.4GeV: 34.1 140 fb-1 bs MC pΛ Signal Threshold enhancement Bruce Mellado, FPCP04 10/08/04

Improved BF(B0ppKS) Measurement Preliminary +6.5 - 5.8 Re-analysis with 140 fb-1 with signal yield 28.6 with Mpp<2.85 GeV Threshold enhancement in pp PRL92 131801, 2004 Threshold enhancement Phase Space MC Bruce Mellado, FPCP04 10/08/04

Pentaquark + Search in B0ppKS Preliminary Search for a pKS resonance at ~1.54 GeV as observed in other experiments Corresponds to + (S=+1) with ududs Background shape from side-band data 1.53<M(pKS)<1.55 GeV Negative Search Bruce Mellado, FPCP04 10/08/04

Inclusive Pentaquark +pKS Search Preliminary 123 fb-1 Clean peak for c+pKS (52K events) but no narrow structure at 1.54 GeV Number of checks: stringent cuts on KS, require recoiling K- and/or anti-proton with all possible combinations. c+ visible but no pentaquark Bruce Mellado, FPCP04 10/08/04

Inclusive Pentaquark +pKS Search (cont) Preliminary Developed model independent limit setting Signal is extracted as a function of p* and corresponding 95% CL limit is calculated 95% CL UL BF< 182.8 (363.1) fb for =1 (8) MeV Bruce Mellado, FPCP04 10/08/04

Pentaquark +pKS Search Using K Interactions in the Detector Material Use secondary pK pairs. Projectile has low energy, similar to most experiments, which observed + (1520) yield is 15519±412 events Mass consistent with PDG No evidence of + found 155 fb-1 pKS pK- nothing (1520) 17cm p K Slide1 Bruce Mellado, FPCP04 10/08/04

Pentaquark +pKS Search K Using Interactions … (cont) 155 fb-1 Limit setting procedure Assume + is narrow Fit M(pKS) to resolution function (~2MeV) Fix mass at different points and scan wide mass interval Fit result for M(pKS) =1.54 GeV: N=29±65 events Upper Limit: N<94 events at 90%CL (Feldman-Cousins method) Yield Slide1 ZEUS-1 CLAS+1 m, GeV Search range Bruce Mellado, FPCP04 10/08/04

Improved BF(B+ppK+) Measurement Preliminary Re-analysis with 140 fb-1 (Belle) and 89 fb-1 (BaBar) Results on BF consistent with PRL92 131801 (2004) Threshold enhancement in pp Mpp<2.85 GeV Full Mpp Range Belle Side Band Signal Bruce Mellado, FPCP04 10/08/04

Search for ++pK+ in B+ppK+ Preliminary Pentaquark *++pK+ (uuuds) predicted to lie in 1.43<M(pK+)<1.70 GeV No evidence was found for *++pK+, 90% CL limits were set Other experiments have also reported negative searches 1.6<M(pK+)<1.8 GeV Belle No background With background Bruce Mellado, FPCP04 10/08/04

Inclusive Search of Pentaquark 5---- and 50-+ 123 fb-1 Preliminary NA49 gave evidence of -- (S=+2, dsdsu, 1.862 GeV) Displaced Vertexes Two displaced vertexes with loose particle ID Select masses near nominal 0 and - Control samples (1530)*- and c(2470)0 Bruce Mellado, FPCP04 10/08/04

Inclusive Search of Pentaquark 5-… (cont) (1530)*- c(2470)0 Bruce Mellado, FPCP04 10/08/04

Charge conjugation is assumed Preliminary 123 fb-1 Other inclusive searches for other pentaquarks were performed 5-, 50, N50, N5+ in the 0K and 0K modes No evidence was found 5 Charge conjugation is assumed Bruce Mellado, FPCP04 10/08/04

Preliminary 123 fb-1 Bruce Mellado, FPCP04 10/08/04

B Decays Involving Charm Searches for Charmed Pentaquarks Bruce Mellado, FPCP04 10/08/04

B0D(*)-pp+ and B0 D(*)0pp New Observation Preliminary 112.5 fb-1 B0D*-pp+ 130 ± 14 B0D-pp+ 238 ± 22 B0D*0pp 13 ± 4 B0D0pp 96 ± 11 BaBar CLEO New Decay Belle Bruce Mellado, FPCP04 10/08/04

B0D(*)-pp+ and B0 D(*)0pp Estimate compatibility of data to phase space MC with Kolmogorov-Smirnov test in the four B decays Observe asymmetry between M(D0p) and M(D0p) in B0 D0pp decays. K-S prob.=3.5 10-4 B0 D0pp K-S prob.=0.77 M(D0p)+cc M(D0p)+cc MC uduuc MC uuduc Bruce Mellado, FPCP04 10/08/04

M(D0p)/M(D0p) asymmetry in B0 D0pp uduuc 112.5 fb-1 uuduc Bruce Mellado, FPCP04 10/08/04

Search for Charmed Pentaquarks in B0D(*)-pp+ and B0 D0pp 39321 Preliminary Look for c0 D(*)-p (ududc) and c*+ D0p (uuudc) No evidence of charmed pentaquark with mass 3.1 GeV (H1) 90% CL limit setting H1 Slide1 Bruce Mellado, FPCP04 10/08/04

BF(B-c+p-) Measurement Preliminary 140 fb-1 Observation of a new 2-body decay B-Sc02455 p ~25% of the BF 264±20 BF in units of 10-5 B-Lc+pp - 18.1 20.1±1.5 ±2.0±5.2 B-Sc02455 p 8.4  3.67±0.36 ±0.95 B-Sc02520 p 2.9  1.26±0.12 ±0.33 SC(2455)0 32.6 + 6.6 - 5.9 + 5.7 - 5.0 SC(2520)0 12.8 Bruce Mellado, FPCP04 10/08/04

M(c+p) structure in B-c+p- Preliminary 140 fb-1 (Lc+p) mass Low mass structure (LC+p) Phase space function B signals by DE fit for each mass bin M(Lc+p -)>2.6 & M(pp-) >1.6GeV/c2 to remove Sc(2455/2520) & D(1232) 6.2 s significance +0.02 -0.03 M = 3.34 ±0.02 GeV GBW = 0.09±0.04 ±0.04 GeV +0.77 - 0.72 BF = ( 3.87 ±0.43 ±1.01 ) x 10 - 5 SC0(LC+p-) Bruce Mellado, FPCP04 10/08/04

M(c+p) structure in 3-4 Body Decays Preliminary 140 fb-1 B-(c+p)- Four body decay BF B0(c+p)+- improved Is the 4-body decay consistent with phase space hypothesis? B0(c+p)+- Phase space MC Bruce Mellado, FPCP04 10/08/04

Outlook and Conclusions Wealth of data coming from the B factories on B decays involving Baryons First observation of B+ΛΛK+ (bsss) and B+pΛ reported. Limit set on B+ΛΛ+ decay. Improve a number of BF measurements First observation of B0D-pp+. Observe asymmetry between M(D0p) and M(D0p) in B0D0pp Confirm dominance of multi-body final states and baryon-antibaryon threshold enhancements Bruce Mellado, FPCP04 10/08/04

Outlook and Conclusions (cont) Pentaquark searches in B factories so far negative No evidence so far of strange (, 5, N5) and charmed (c) pentaquarks in both exclusive B decays and inclusive searches in e+e- Evidence reported by Belle on M(c+p) structure in B-(c+p)- with 6.2 significance M(c+p)3.3 GeV BW=0.090.040.04 GeV Bruce Mellado, FPCP04 10/08/04

Back-up Slides Bruce Mellado, FPCP04 10/08/04

B0D(*)-pp+ and B0 D(*)0pp (cont) Preliminary 112.5 fb-1 Pin down dynamics of B decay by looking into Dp & pp spectra Observe asymmetry between M(D0p) and M(D0p) in B0 D(*)0pp decays Probability that data is compatible with phase space MC Bruce Mellado, FPCP04 10/08/04