1 Hadron Spectroscopy at BABAR BY Usha Mallik (University of Iowa) Representing The BaBar Collaboration The International Light-Cone Workshop July 7, 2005 Cairns, Australia

2 Topics:  Hadron Spectroscopy: –D s (cs) States : Inclusive and Exclusive studies –Double Charmonium Production; the X and the Y –Pentaquarks –Charmed Baryon studies  Summary  What can we learn from each other ?

3 Plan to Double Dataset by Next Summer The BABAR Detector at PEP-II and the Dataset  E cm = GeV And Much More

4 D SJ (cs) Spectroscopy  New States D SJ (2317) + and D SJ (2460) + –First Observed Inclusively in e+e- Collisions  Previously Established States with Likely J PC D S (2112) +  1 -(+) S-Wave (c and s spins aligned) D s  also D S  0 D S (2536) +  1 +(+) P-Wave ( needs confirmation ) D*(2010 )+ K 0 D*(2007) 0 K + D S (2573) +  2 +(+) D-Wave ( consistent with) D0K+D0K+ Ground State D S (1969) + : J P =0 -, c and s spins opposite, in S-wave

5 Belle 87 fb -1 BaBar 125 fb -1 Discovery D s *  D s  Discovery of D sJ States e+e-  cc  D sJ + X D sJ (2317) +  D s +  0 D sJ (2460) +  D s *+  0 M(2460) – M(2112) BABAR, BELLE, CLEO mutually confirm, also CDF (2317) Caution: These Decays cross-feed

6 Decays violate isospin: mixing Look for radiative and dipion transitions If is, expect is forbidden is forbidden If is, expect is allowed is allowed (also D-Wave) (for a conventional meson)

7 D sJ (2460): 0 ± excluded Search for D sJ →D s  BaBar 125 fb -1 Excludes 0 ± if present D sJ (2317): compatible with 0 + BABAR: PRD 69 (2004) (R) ; BELLE : PRL 92 (2004) BABAR Belle 87 fb -1

8 D sJ (2460) → D s  0  Kinematics D sJ (2460) hep-ex/ BABAR

9 BELLE: PRL 91 (2003)262002

10 Exclusive Production of D * SJ in B ->D SJ (*)+ D (*)  Kinematic Constraints Help, Even though Lower Stats Reduces Backgrounds Measure Ratios of Branching Fractions Measure Br  Well-defined Initial State Test D SJ (*) Spin Assignments Reconstruct one B: other is a B for Study

11 B  D sJ (*)+ D (*) BABAR: PRL 93 (2004) Data sample: 122 million B pairs D sJ * (2317) +  D s  0 D sJ (2460) +  D s *  0 D sJ (2460) +  D s  m ES m(D sJ m(D sJ ) Full reconstruction of the exclusive  decay Sum over charged and neutral B’s 112 ± 14 events 139 ± 17events We measure: m ES m(D sJ m(D sJ ) BABAR

12 B  D sJ (*)+ D* Results B.F. (10 -3 ) D sJ *(2317) +  D s  0 D sJ (2460) +  D s *  0 D sJ (2460) +  D s  B0B0 1.5 ± 0.4 ± 0.2( )5.5 ± 1.2 ± 1.0( )2.3 ± 0.3 ± 0.3( ) B+B+ 0.9 ± 0.6 ± 0.2( )7.6 ± 1.7 ± 1.8( )1.4 ± 0.4 ± 0.3( ) B.F. Products for B  D sJ (*)+ D* m(D s +  0 )m(D s *+  0 )m(D s  ) B0B0 B0B0 B0B0 B+B+ B+B+ B+B+ D sJ (2317) D sJ (2460) BABAR BELLE: PRL 91 (2003) Data sample: ~124 million B pairs in agreement with Belle results

13 B  D sJ (*)+ D Results B.F. (10 -3 ) D sJ *(2317) +  D s  0 D sJ (2460) +  D s *  0 D sJ (2460) +  D s  B0B0 1.8 ± 0.4 ± 0.3( )2.8 ± 0.8 ± 0.5( )0.8 ± 0.2 ± 0.1( ) B+B+ 1.0 ± 0.3 ± 0.1( )2.7 ± 0.7 ± 0.5( )0.6 ± 0.2 ± 0.1( ) B.F. Products for B  D sJ (*)+ D in agreement with Belle results m(D s +  0 ) m(D s *+  0 ) m(D s  ) B0B0 B0B0 B0B0 B+B+ B+B+ B+B+ D sJ (2460) D sJ (2317) BABAR

14 Two body decay B  DD SJ forces D SJ to populate helicity zero only Analyze angular distribution (cos h ) of daughter of D SJ BELLE Finds from Angular Distribution – D SJ (2317)* J = 0 (Preliminary) hh B D sJ D  0 – Spin Analysis of B  DD SJ *

15 B  D sJ (2460) + D D sJ + (2460) DsDs  hh J=1 (  2 =4.0/4) preferred to J=2 (  2 =36.4/4) Data points from m(D s  fits corrected for detector acceptance and efficiency J=2 J=1 confirms Belle measurement BABAR

16 e.g. Godfrey-Isgur model S-wave P-wave Ds+Ds+ D s *+ D s1 (2536) + D sJ (2573) + D s0 (2317) D s1 (2460) D sJ * (2317) +, D sJ (2460) + –Observed by BaBar, Belle and CLEO –Unexpectedly below threshold for DK and D*K, respectively –Consistent with P-wave cs states but other interpretations not ruled out –If cs, observed decays D sJ * (2317) +  D s +   D sJ (2460) +  D s *+   are isospin violating  narrow –D sJ (2460) +  D s +  also observed (and used to determine J) Taking Stock of cs States Several other explanations exist e.g. Molecules or Hybrids

17 New Charmonium-like States X(3872)  J/  π + π - Average Mass ± 0.5 MeV Narrow  < % CL (D 0 D* 0 threshold at ± 1.0) CDF PRL (2004) BELLE PRL (2003) BABAR hep-ex/ D0 PRL (2004)

18 B +  X(3872) 0 K + Reconstruction Recent Update: BELLE (256 fb -1 ) hep-ex/ , BABAR hep-ex in preparation Background from B decays to same final state J/  K

19 About X(3872) Search for a Charged Partner From 212 fb -1 Data BABAR Observed No Signal for X - Phys. Rev. D71 : , 2005 B(B 0  X - K +, X -  J/  π - π 0 ) < 5.4 X 10 90% CL B(B -  X - K S, X -  J/  π - π 0 ) < 11 X 10 90% CL Charmonium State : no isospin partner expected (data) Molecule State (?) : highly suppressed B 0  X(3872) predicted Diquark-antidiquark State : different masses of X(3872) in B0 and B+ decays predicted, |  M| > 5 MeV E. Braten, M. Kusunoki hep-ph/ L. Maiani, F. Piccini, A.D. Polosa, V. Riquer PRD 71(2005)

20 B 0  X(3872) 0 K S Reconstruction Background

21 Other searches for X(3872) Search for X(3872) in events with initial state radiation (if J PC = 1 -- ) Search for X(3872) in B  X(3872)K in the spectrum recoiling against K from the B decays (with the other B fully reconstructed): B(X(3872) in B  X(3872)K, X(3872)  J/  ) < 3.2 X at 90% CL and so, BF(X(3872)  J/  +  - )  4.3 % m es of all the exclusively reconstructed B m ES : B mass using beam energy Use BABAR-BELLE average BF(B +  X(3872)K +, X(3872)  J/  ) = (13.2  2.2) x PRD 71 (2005) BABAR

22 BELLE: 256 fb  C= +1 favored hep-ex/ X(3872) :  +  - Invariant Mass Distribution BELLE: hep-ex/ BABAR: hep-ex in prep. Di-pion mass consistent with  0   +  -, again C =+1 ; S-wave J/   favored: J ++ favored over J -+ Isospin violating: predicted D 0 D* 0 molecule, Swanson PLB 588 (2004) 189, Törnqvist PLB 590 (2004) 209 Also X(3872)  π + π - π 0 J/ 

23 X(3872): BELLE Finds Data Disfavors 0 ++ and 2 ++, Leaving 1 ++ cc ? 1 ++ is  c1 ’ X(3872) is too light M[Ge DDThreshold 3872

24 }C=+1 }C=-1  c,  c,  c (2S) J/ ,  (2S) G. T. Bodwin, E. Braaten & J. Lee PRD67, (2003) Study double charmonium in e + e - annihilation Double Charmonium Production Theorists predict the cross sections of the two processes to be comparable

25 Reconstruct J/  or  (2S) and Look at Recoil Mass BABAR: 124 fb -1, hep-ex/ cc  c ( 2S )  c0 BELLE: PRD 70 (2004) BABAR

26 Double Charmonium Production from BELLE From BELLE Evidence of X(3940): 4.5  m = 3940 ± 12 MeV,  < 96 MeV at 90% CL

27 8  : 253 fb -1 with 59 ±11 Events A Near-threshold  J/  Mass Enhancement in B  K  J/  at 3940 MeV/c 2 BELLE: Phys. Rev. Lett. 94: , 2005 Dominantly cc BELLE Is it the same as X(3940) ?

28 A Broad Structure in J/  π + π - Mass near 4.26 GeV e+e-   ISR J/  +  - in Initial State Radiation BABAR: 211 fb -1 (preliminary)  (2S)125±23 excess events Recoil Mass Consistent with zero hep-ex/ , submitted to PRL

29 In addition to  (2S) a Broad Structure is Observed in ISR Events J PC = 1 -- ; Can be Characterized by a single Resonance at 4.26 GeV and Width ~ 0.09 GeV Too low Statistics to Discern if Multiple States together - (e.g. S and D waves can mix)  +  - mass distribution from Y (4260) Y (4260)  J/  S-wave phase space Why no rise in R ? 4.26 D*D* threshold 3.77 BES, PRL 88 (2003), BABAR

30 Pentaquark searches Pentaquark discovery in 2003, (  confirmed by 13 experiments) (statistical significance of individual experiments is not high ~5-6  ) Also many negative searches reported, especially a recent high statistics study by CLAS Claims of exotic narrow baryons LEPS, CLAS, …: M=(1542±5)MeV/c 2  <21MeV/c 2 NA49: M=(1862±2)MeV/c 2  <18MeV/c 2 H1: M=(3099±6)MeV/c 2  <28MeV/c 2 S I3I3  5 (1540) + [uudds]  5 (1860)  [ddssu]  5c (3100)  [uuddc] The anti-decuplet for Pentaquarks

31 Inclusive and Exclusive Searches at BABAR  5 +,  5 --,  5 0,  5c 0

32 accepted by PRL e+e- annihilation (~123 fb -1 ) hep-ex/

33 accepted by PRL

34 Upper Limit

35 No Signal Observed by CLAS in this Mode with ~40 times Statistics, now repeating other modes BABAR studies electro- and hadro-production in interactions with the material of the inner detector ; Observes no signal So far, evidence of  5 claimed in — real/virtual photoproduction — hadroproduction photoproduction

36 Detector Tomography with pK S 0 vertices 230 fb -1 BABAR e-e- e+e+

37 pK s mass distribution Mass resolution ~2 MeV Clear K s from      Decays Selected Protons Selected from Particle ID BABAR

38 Associate p Ks Vertex with  ± and K ± BABAR  (1115)

39 No Pentaquark Observed by BABAR BABAR

40 Charmed Baryon Studies  Precision Mass Measurement of  C + (cud)  Production Process and Ratio of Branching Fractions of  C 0 (csd) cc or B   C 0 + X  Production Process and Ratio of Branching Fractions of  C 0 (css) cc or B   C 0 + X  C 0   -  +   -  +  -  +   - K -  +  +

41 Mass Measurement of  C + Using Low-Q-value Decay Modes of  C +   K S K + and  C +   0 K S K + m(  C +   K s K + ) = ± (stat.) ± (sys.) MeV/c 2 m(  C +   0 K s K + ) = ± (stat.) ± (sys.) MeV/c2 BABAR Result : m(  C + ) = ± 0.14 MeV/c 2 PDG Value ± 0.6 MeV/c 2 Cross-checks: m(  C +  pK  + ) = ± 0.12 (stat.) ± 0.45 (sys.) MeV/c 2 m(  C +  pK s ) = ± 0.03 (stat.) ± 0.43 (sys.) MeV/c2 m(  ) = ± 0.01 (stat.) ± 0.04 (sys.) MeV/c 2 PDG Value = ± MeV/c 2 m(K S ) = ± 0.04 (stat.) ± 0.26 (sys.) MeV/c2 PDG Value = ± MeV/c 2 BABAR hep-ex/ , submitted to PRD

fb -1 c0-π+c0-π+ c0-K+c0-K+ B(  c 0   -K+) B(  c 0   -π+) = ± ± Goals: Measure Ratio of Decay BFs : Study Production Mechanism BABAR hep-ex/ , submitted to PRL

43 Study  c 0 Momentum (p*) in e+e- rest frame  c 0 from B Decays  c 0 peak from B’s absent in off-peak B (B   c 0 X) B (  c 0   -  +) = 2.11 ± 0.19(stat.) ± 0.25(syst.) X c0-π+c0-π+  (e+e-   C 0 X) B (  c 0   -  + ) = 388 ± 39(stat.) ± 41(syst.) fb Results: Efficiency Corrected BABAR 116 fb -1 hep-ex/ , submitted to PRL

44 Inclusive  c 0 Studies Branching Fractions and Production Mechanism from p* Spectrum Decay Modes of  C 0 Studied   -  +,  -  +  -  +, and  - K -  +  +  C 0   -  + P* > 2.8 GeV/c 225 fb -1 Results: BABAR SLAC-PUB-11323, hep-ex/

45 The p* Spectrum from  - π + Mode Off-peak only On & Off-peak Not Corrected for Efficiency B   C 0 Production (First Observation) Analysis in Progress BABAR SLAC-PUB hep-ex/

46 Summary & Conclusion  Unfolding cs spectroscopy  New States X(3872), Y(3940)… and Y(4260)?  Copious Double Charmonium Production  Pentaquark Fading ?  Exciting Charmed Baryon Spectroscopy  What can we Provide ?

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51 Kaon momentum spectrum

52 Kinematics Mutual cross feed widths are consistent with zero No evidence for Belle 87 fb -1 BaBar 125 fb -1

53 D sJ (2460): 0 ± excluded Search for D sJ →D s  BaBar 125 fb -1 Belle 87 fb -1 Excludes 0 ± if present D sJ (2317): compatible with 0 + BABAR: PRD 69 (2004) (R) ; BELLE : PRL 92 (2004) BABAR

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58 Search in Inclusive B  XK Reconstruction

59 Branching fractions from b  xk study

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61 D s +  f p +  Results D * and g  selection analogous to inclusive analysis D s +   (  K + K  )   fully reconstructed measure branching fraction product: Signal 212 ±19 Dividing by our measurement of B (B 0  D s *+ D* - ), we obtain B (D s +  + ) = (3.6 ± 0.9)% (CLEO) to be compared with Readjustment of many results needed! Not used yet for other results in this talk B (B 0  D s *+ D *  ) x B (D s +  + ) = (8.71  0.78 (stat) ) x10 -4 B (D s +  + ) = (4.71 ± 0.47 (stat) ±0.35 (syst) )%

62 Electroproduction in e - Be BABAR