New States Containing Charm at BABAR PHENO 06 Symposium A.J. Edwards - Stanford University May 15

Outline Λc(2880)+ and Λc(2940)+ → D0p Ξcc+ and Ξcc++ New measurements of the Λc(2880)+ First observation of the Λc(2940)+ Ξcc+ and Ξcc++ Are double-charm baryons among us? D*sJ(2317)+ and DsJ(2458)+ An update on their properties; absolute BFs for DsJ(2458)+ X(3872) and Y(4260) Update & confirmation of X(3872) C-parity Searches for new Y(4260) decay modes 2

Λc(2940)+ 3

Charm Baryon Spectroscopy Two new observations in cc continuum of particles with decays to D0p Discovery of Λc(2940)+ The first observation of Λc(2880)+ → D0p Λc(2880)+ D0p Threshold π 4

A New Decay Mode, Mass and width hep-ex/0603052 (sub. to PRL) 287 fb–1, A New State Λc(2880)+ N=2280±310 (>7 σ) Λc(2940)+ M = (2939.8±1.3±1.0) MeV/c2 Γ = (17.5±5.2±5.9) MeV Λc(2940)+ A New Decay Mode, Mass and width Λc(2880)+ M = (2881.9±0.1±0.5) MeV/c2 Γ = (5.8±1.5±1.1) MeV Wrong sign D0p PDG04: M=2880.9±2.3 MeV/c2 Γ < 8 MeV D0 mass sidebands 5

Λc(2940)+ Sascha Migura et al. hep-ph/0602153 hep-ex/0603052 Three Λc states predicted at mass ~2940 MeV/c2: JP= (1/2)+, (1/2)–, and (3/2)– The Λc(2880)+ is near a predicted (3/2)– state. Λc(2940)+ not observed in Λc+π+π–. Suppression not understood. Expected signal size Neither signal in D+p distribution → both states are Λc’s 6

Doubly Charmed Baryons 7

Doubly Charmed Baryons SU(4) 20'-plet Theoretically Ξcc & Ωcc should exist. The SELEX experiment (hyperon beam) reports Ξcc evidence (with 1,630 Λc) The FOCUS experiment (photon beam) sees no Ξcc evidence (with 19,500 Λc) Strangeness Charm I3 Can they be found in e+e– → qq production? Ξc0→Ξ–π+ 232 fb–1 Large numbers of single charm baryons in 232 fb–1 data set e.g. ~600,000 Λc+ and ~12,000 Ξc0 Double charm baryon e+e– cross section predictions: 1 - 250 fb Theoretical BFs to Λc+K-π+, Λc+K-π+π+, Ξc0π+, Ξc0π+π+ ~ a few percent Λc+→pK–π+ 232 fb–1 8

Doubly Charmed Baryons SELEX Ξcc+ Λc+→pK–π+ 232 fb–1 Λc+K–π+ p*>2.3 GeV/c Λc Sidebands 95% C.L. SELEX Ξcc++ Λc+K–π+π– p*>2.3 GeV/c < 95% C.L. With some assumptions about branching fractions: < 1.5 pb @ 95% C.L. (p* > 2.3 GeV/c) < 1.3 pb @ 95% C.L. (p* > 2.3 GeV/c) This does not rule out any theoretical production cross sections. 9

Doubly Charmed Baryons SELEX Ξcc+ Ξc0π+ p*> 2 GeV/c < 1.3 fb 95% C.L. SELEX Ξcc++ < 3.4 fb 95% C.L. Ξc0π+π+ p*> 2 GeV/c Ξc0→Ξ–π+ 232 fb–1 With some assumptions about branching fractions: The production cross section limits for doubly charmed baryons are near or below σ(e+e– → Ξc0X) 10

DsJ*(2317) and DsJ(2460) 11

Charm-Strange Mesons DsJ*(2317) and DsJ(2460) first observed by BABAR and CLEO in cc continuum events, and by Belle in B decays Both masses unexpectedly low: below DK and D*K threshold, respectively Only isospin-violating or electromagnetic decays kinematically allowed  narrow widths Decay pattern and decay angular distributions consistent with interpretation as JP=0+ and JP=1+, respectively D*K D0K BABAR: 91 fb-1 PRL 90, 242001 (2003) CLEO: 13.5 fb-1 PRD 68, 032002 (2003) Belle: 124M BB PRL 91, 262002 (2003) 12

Charm-Strange Mesons Assuming DsJ*(2317) and DsJ(2460) have JP = 0+ and 1+ respectively, the decay channels below are allowed or forbidden as indicated. All of the above decay modes have been searched for. All “Seen” modes are also “Allowed” 13

D*sJ(2317)+ Original D*sJ(2317) discovery mode update 232 fb-1 sub. to PRD No indication of neutral or doubly-charged signal, ruling out some exotic interpretations N=3180±80 2 MeV/c2 Bins Ds+π– Circles: Ds sidebands Ds*(2112) reflection Ds+π+ Dark shade: DsJ(2460) reflection 2317 MeV/c2 14

Open points: Ds sidebands DsJ(2460)+ DsJ(2460) decay channels Original: Ds* π0, Ds*→Ds+  Additional: Ds+ Additional: Ds+π+π- DsJ(2460)+Ds+π0 Dark shade: DsJ*(2317)+ reflection Open points: Ds sidebands Light shade: Ds*(2112)+ N=560±40 232 fb-1 sub. to PRD DsJ(2460) → Ds+π+π- DsJ*(2317) N=123±15 N=6±3 DsJ(2460)+Ds+  Backgrounds N=920±60 15

DsJ(2460)+ From the Ds+π+π– decay channel More precise BR measurements Limits set for additional decay channels. 16

DsJ(2460)+ Absolute Branching Fractions Sample with one B fully reconstructed (Breco) Study decays of other B  (D*+, D+, D*0, D0) X Observe DsJ(2460)- signals in the recoil mass (mX) hep-ex/0605036 e- D* p e+ Breco Bsignal D*0 D*+ D0 D+ X BF( ) = (0.88 ± 0.20 ± 0.14) % 17

DsJ(2460)+ Absolute Branching Fractions Combine with previously measured product branching fractions 230M BB and Using B(Ds→φπ)=4.62 % Sum of known branching fractions: 0.76±0.17 18

X(3872) and Y(4260) 19

Updated result from BABAR X(3872) → J/ψ π+ π– Updated result from BABAR Initial discovery of B– → X(3872)K– → J/ψ π+π– K– by Belle Confirmed by CDF, DØ and BABAR PRD 73, 011101 (2006), 232M BB hep-ex/0505038 N=49±8 N=61±15 (6.1 σ) Updated 256 fb-1 Solid Hist.: mES sidebands 20

X(3872) → J/ψ γ BABAR confirms X(3872) → γJ/ψ 287M BB N=19±6 (3.4 σ) BABAR confirms X(3872) → γJ/ψ This implies that X(3872) is a C=+1 state All evidence points towards X(3872) being an isoscalar 1++ state 21

Y(4260) → J/ψ π+ π– Searching for X(3872) in ISR events but found Y(4260) → JPC = 1– – 233 fb-1, PRL 95, 142001 (2005) (2S) Peak cross section: σ(e+e-Y)=(51±12) pb 22

CLEO results confirm Y(4260) Y(4260) → J/ψ π π CLEO results confirm Y(4260) hep-ex/0602034 Consistent with BABAR cross section No J/ψ π0 decay signal seen N=37 N=8 23

Y(4260) Searches in ISR Processes e+e– → γISR pp, (232 fb–1) PRD 73, 012005 (2006) e+e–→γISR DD (289 fb-1) To.b.subm.to PRL e+e–→γISRΦπ+π– (232 fb-1) To.b.subm.to PRD Y(4260) M(K+K-) ψ(3770) γISR detected γISR detection not required γISR detected 24

Summary 25

Summary Charm spectroscopy at BABAR is very active and pushing the boundaries of experimental knowledge. Λc(2940)+ first observation; absence in D+p is consistent with Λc interpretation. Λc(2880)+: first observation in D0p decay mode; improved (M,Γ); absence in D+p is consistent with Λc interpretation. Ξcc+ and Ξcc++ are searched for but not found; limits not theoretically restrictive. Updates on DsJ*(2317)+ and DsJ(2460)+; absolute branching fraction measurements for DsJ(2460)+ X(3872) update and confirmation of positive C parity from J/ψγ mode Y(4260): limits on DD, φπ+π–, and pp decay modes 26