1. July 7, 2008SLAC Annual Program ReviewPage 1 New Charmonium-like States Arafat Gabareen Mokhtar SLAC Group-EC (B A B AR ) DOE Review Meeting July 8 th, 2008

2. July 7, 2008SLAC Annual Program ReviewPage 2 Outline *Charmonium spectroscopy from Initial State Radiation (ISR) processes: –e + e - → γ ISR Y(4260)→J/ψπ + π - –e + e - → γ ISR Y(4350)→ψ(2S)π + π - *Charmonium spectroscopy from B-meson decay: –B→KX(3872), X(3872) →J/ψπ + π -, D 0 D 0*, J/ψγ –B→KY(3940), Y(3940) →J/ψω –B→KZ - (4430), Z - (4430)→ψ(2S)π - *Summary and outlook

3. July 7, 2008SLAC Annual Program ReviewPage 3 Charmonium spectroscopy from ISR processes *Initial State Radiation (ISR) can lead to the production of charmonium states at lower c.m. energy (i.e. via radiative return) e.g. ~18M J/ψ events and ~6M ψ(2S) events have been produced by ISR e+e+ e-e- γ ISR γ*γ* J/ψ,ψ(2S),ψ(3770), etc

4. July 7, 2008SLAC Annual Program ReviewPage 4 The Y(4260) *Observed in ISR events –γ ISR detection is not required –J PC = 1 -- m Y =4259 ± 8 +2 -6 MeV/c2 Γ Y =88 ± 23 +6 -4 MeV *Г Y,ee. BF(Y(4260)→J/ψπ + π - ) = (5.5±1.0 +0.8-0.7) eV e + e - →γ ISR J/ψππ 233 fb -1 B A B AR : PRL 95, 142001 (2006) ψ(2S) Background from J/ψ mass sideband Confirmed by:  CLEO-c (scan): PRL 96, 162003 (2006) The observed rate to J/ψπ 0 π 0 confirms I=0  CLEO III (ISR) : PRD 74, 091104 (2006)  BELLE (ISR): PRL 99, 142002 (2007) No evidence for Y(4260)→ππφ, DD, pp

5. July 7, 2008SLAC Annual Program ReviewPage 5 The Y(4350) *After the Y(4260)→J/ψπ + π - discovery, it was natural to search for the decay e + e - →γ ISR Y(4260), Y(4260)→ψ(2S)π + π - *However, the B A B AR analysis found a new peak that does not match the Y(4260) mass/width –m = 4324 ± 24 MeV/c 2 –Γ = 172 ± 33 MeV *e + e - requires this state to have J PC =1 -- *Seems impossible to assign both as charmonium; however, there are two towers of cc 1 -- states, which might mix to yield the observed spectrum B A B AR : PRL 98, 212001 (2007) Y(4350) has been confirmed (BELLE): PRL 99, 142002 (2007)

6. July 7, 2008SLAC Annual Program ReviewPage 6 Charmonium spectroscopy from B-meson decay *Many conventional Charmonium states observed; J/ψ, ψ(2S), ψ(3770),  c,,  c (2S),  c0,  c1, *In addition, new “charmonium-like” states observed with a recoil K: –X(3872) –Y(3940) –Z - (4430) J/ψ, ψ(2S),  c,  c,... Typical BF ~(0.5 – 1.0) x 10 -3 K -, K 0, K * (890),K 1 (1270),K 1 (1410),... Color suppressed

7. July 7, 2008SLAC Annual Program ReviewPage 7 The X(3872) (I) *Discovered by BELLE: PRL 91, 262001 (2003) *Confirmed by: –CDF: PRL 93, 072001 (2004) –D0: PRL 93, 162002 (2004) –BABAR: PRD 71, 071103 (2004) (data: 117 fb -1 ) –BABAR: PRD 73, 011101 (2006) (data: 211 fb -1 ) –BABAR: PRD 77, 111101 (2008) (full data set: 413 fb -1, final result) B +  X(3872)K + B 0  X(3872)K S 8.6  2.3  413 fb -1

8. July 7, 2008SLAC Annual Program ReviewPage 8 m(J/ψγ) (GeV/c 2 ) The X(3872) (II) *X(3872) decays into J/ψγ: BABAR (PRD 74, 071101 (2006))  implies positive C- parity: C=+1 –being updated to full statistics; –Search for decay ψ(2S)γ under internal review *No evidence for charged partner (X - ) BR(B 0 →X - (J/ψπ 0 π - )K + )<5.4x10 -6 @ 90% C.L. B+B+ B0B0 B A B AR : PRD 71, 031501 (2005) 212 fb -1  I = 0

9. July 7, 2008SLAC Annual Program ReviewPage 9 The X(3872) (III) B A B AR : PRD 77, 011102 (2008) 347 fb -1 No X  D  D  ψ(3770) X(3872) Evidence for X(3872)→D 0 D 0* BF(B 0 →X(3872)K 0, X(3872)→D 0 D 0* ) = (2.22±1.05±0.42)x10 -4 BF(B + →X(3872)K +, X(3872)→D 0 D 0* ) = (1.67±0.36±0.47)x10 -4 This, and absence in DD, consistent with unnatural J P

10. July 7, 2008SLAC Annual Program ReviewPage 10 The X(3872) (IV) *The mass of X(3872) from the D 0 D 0* is ~4.5σ higher than that from J/ψπ + π - *The quantum numbers of the X(3872) are either 1 ++ or 2 - + (CDF) *The shift in the mass can be explained if X(3872) is 2 - + (Dunwoodie & Zeigler PRL 100, 062006 (2008)) *The nature of X(3872) is not completely understood. Is it charmonium state? (mass is ok for 2 - + ground state) Molecule? Tetraquark? Hybrid (cc+gluon)?

11. July 7, 2008SLAC Annual Program ReviewPage 11 The Y(3940) (I) *The Y(3940) was discovered (BELLE: PRL 94, 182002 (2005)) in the decay B→Y(3940)K, Y(3940)→J/ψω *Confirmation of Y(3940) in B A B AR : arxiv:0711.2047 (accepted for publication in PRL) *The B A B AR data sample is ~1.4 times larger than BELLE’s data sample *Separate treatment for B + and B 0 *Branching fractions for B→Y(3940)K, and B →J/ψωK are obtained separately for B + and B 0 BABAR preliminary

12. July 7, 2008SLAC Annual Program ReviewPage 12 The Y(3940) (III) *The B + and B 0 signals are fitted simultaneously (χ 2 fit) with an S-wave Breit- Wigner for the resonant term and a Gaussian function for the non-resonant contribution *Lower mass and narrower width (relative to BELLE results) are obtained: –m = 3914.6 +3.8 -3.4 (stat) ± 2.0(syst) MeV/c 2 –Γ = 34 +12 -8 (stat) ± 5(syst) MeV (BELLE: m = 3943±11±13MeV/c 2 ; Γ = 87 ±22 ±26 MeV) *The ratio between B 0 and B + candidates in the Y(3940) region and in the non-resonant contributions are measured: –R Y =0.27 +0.28 -0.23 (stat) +0.04 -0.01 (syst) 3σ below the isospin expectation –R NR =0.97 +0.23 -0.22 (stat) +0.03 -0.02 (syst) B + →J/ψωK + B 0 →J/ψωK 0 BABAR preliminary

13. July 7, 2008SLAC Annual Program ReviewPage 13 The BELLE Z - (4430) *BELLE reported (PRL 100, 142001 (2008)) a resonance-like structure in ψ(2S)π ± ; m=4433 ± 4(stat) ± 2(syst); Γ=45 +18 -13 (stat)+ 30 -13 (syst) *If this resonance is confirmed  first evidence for a genuine ccud “tetraquark” state, since it is an isovector and carries hidden charm BELLE K * (892) and K * 2 (1430) veto used

14. July 7, 2008SLAC Annual Program ReviewPage 14 Remarks/questions on the Z - (4430) *How does the ψ(2S)π - distribution look for the events in the K * (890) and K * 2 (1430) region? *The assumption that the background under the Z - (4430) signal is polynomial is not realistic *No report on the decay Z - →J/ψπ - from BELLE *BF(B 0 →Z - K +, Z - →ψ(2S)π - )= (4.1 ± 1.0(stat) ± 1.4(syst))x10 -5 *In B A B AR, we use the full dataset (413 fb -1 ) to search for the Z - (4430) *The analysis is under internal review and the B A B AR collaboration will release the results soon

15. July 7, 2008SLAC Annual Program ReviewPage 15 Summary and outlook *The B-factories have played a leading role in the discovery of unexpected states, especially in the charmonium and charm (meson and baryon) sectors *Several new charmonium-like states have been discovered above open- charm threshold, but their nature is not yet understood *B A B AR will soon release new results on charmonium physics (including the search for the Z - (4430))

16. July 7, 2008SLAC Annual Program ReviewPage 16 Backup I: The Y(3940) (IV) *BF(B + →Y(3940)K +, Y(3940)→J/ψω)=(4.9 +1.0 -0.9 (stat) ± 0.5(syst))x10 -5 *BF(B 0 →Y(3940)K 0, Y(3940)→J/ψω)=(1.3 +1.3 -1.1 (stat) ± 0.2(syst))x10 -5 <3.9x10 -5 @ 95% C.L. BELLE: BR(B→Y(J/ψω)K)=(7.1 ± 1.3(stat) ± 3.1(syst))x10 -5 *Both B A B AR and BELLE agree well on the branching fraction of (B) B A B AR provides the first measurements on the total branching fractions: *BF(B + →J/ψωK + ) = (3.5 ± 0.2(stat) ± 0.6(syst) ) x 10 -4 *BF(B 0 →J/ψωK 0 ) = (3.1 ± 0.6(stat) ± 0.3(syst) ) x 10 -4