Quarkonium Working Group Workshop (Nara, NWU, December 2-5/2008) Charged Zs at Ruslan Chistov (ITEP, Moscow) Representing the Belle Collaboration c D1*+ D0 d Introduction Observation of Z(4430)+ + at Belle

Observation of Z+1,2+c1 at Belle u c Update of Z(4430)+ at Belle (NEW) Summary 1 L> 870 fb-1 High Luminosity has permitted us to obtain unexpected non-trivial results on charm spectroscopy, particularly with charmonium in the final state. This has modified our understanding of

known and predicted charmonia levels 2 Observed and predicted charmonia A number of unexpected exotic states above DD(*) thresholds that do not fit into available cc slots Described well the observed spectrum of cc states 3

The mechanisms of new particle production at Bfactories From B-decays, e.g. B+X(3872)K+ In double charmonium production, e.g. e+e-J/ X(3940) In fusion, e.g. c(2S) or Z(3930) Can charged Z be in principle produced here?

Yes yet unknown (e+eX+Y- ??) No In radiative return, e.g. e+e- ISRY(4260) J/ +- No Since only neutrals can be produced 4

Observation of the first manifestly exotic state + Z(4430) at Belle (2007) 5 Z(4430)+ at Belle PRL 100, 142001 (2008) Study of BK+: l+l- and J/+- (M()>0.44 GeV); B-candidates inv. mass is

kinematically constrained to mB (experim. resolution for M(+)~2.5 MeV); Horizontal band K*(1430) K*(892) Study it 6 Z(4430) at Belle + Veto PRL 100, 142001 (2008)

Veto Fit: S-wave Breit-Wigner + Background with kinematic thresholds Cross-checks: Z(4430)+ is present in both subsamples Total significance: 6.5 M = (443341) MeV = (44+17-13+30-11) MeV Br(BKZ)xBr(Z(2S)+)= (4.11.01.3)10-5 7 Z(4430)+ at Belle

B+Z+Ks or B0Z-K+ PRL 100, 142001 (2008) Z(2S)S) Charged, I=1 A variety of interpretations: - threshold effect (J.L.Rosner 0708.3496, D.V.Bugg, 0709.1254); - D*D1 molecular state (X. Liu and Y.R. Liu, 0711.0494); - radially excited tetraquark (L.Maiani, A.D.Polosa, V.Riquer, 0708.3997); - baryonium state (C.F.Qiao, 0709.4066 ); - hadro-charmonium (S.Dubinskiy,M.B.Voloshin,0803.2224);

Cannot be a conventional charmonium or hybrid state Should contain light quarks in addition to cc. 8 Belle continued the study of other B(cc) +K- decays New charged Zs decaying +

into c1 PRD 78, 072004 (2008) 9 Study of BK-+c1 Similar selection, then look at DP: B-signal Horizontal band Study it K*(892) K*(1430) 10

Isobar Fit to entire Dalitz Plot: All known K*s below 1900 MeV + K*(892) + K*(1410) + K*0(1430) + K*2(1430) + K*(1680) + K*3(1780) + (Zs) + Interference Efficiency over Dalitz Plot is included 11 The fit results in DP slices without any Zs:

A B C A B C D D Confidence level of this fit: 3x10-10

12 The fit results in DP slices A with one Z: A B C B D C

D Confidence level of this fit: 0.5% Try an additional Z 13 The fit results in DP slices with two Zs: A A B C

B D C D Confidence level of this fit: 42% 14 Parameters of the new EXOTIC Z+1,2 +c1 states and Mass(+c1) distribution No discrimination between J=0 or 1 are the same order as

obtained for other, possibly exotic X,Y,Z states. 15 Systematics and significances (incl. d.o.f.) from various fit models: The worst case, but the params of this new K* are far from those for all known K*s 16 Full Dalitz Plot analysis of BK-+ Data sample from original analysis is used

The same fitting technique as in BKc1 is used New results on Z(4430) + 17 Dalitz Plot slices: Fit without a Z resonance: CL=0.1% No K*3(1780) in the fit model: A

B C D A B C D E E

Introduce Z 18 A results on Z(4430)+ from Dalitz plot NEW fit B C D E

A B C D E The results of the DP fit in its slices with Z: Confidence Level of the fit WITH Z(4430)+ is a

c fi i gn .4 i S 6 is e c n of Z 19

Different fit models and the significance of Z(4430)+ Significance of Z(4430)+ in different fit models is always larger than 5 20 Updated parameters of Z(4430)+ from Dalitz plot fit Sum of 3 slices (K*s veto) P re

li m in ar y Belle confirms the original result on Z(4430)+ Width is larger than original but uncertainties are large 21 Summary of Belle results on manifestly exotic states 2007: Belle observed first charged charmoniumlike

state, Z(4430)+ decaying into + 2008: Belle continued the study of BK(cc) decays and observed two new charged charmoniumlike states Z(4050)+ and Z(4250)+, decaying into +c1 Update on Z(4430)+: Dalitz Plot analysis confirms original observation. The Z(4430)+ has a significance of 6.4. These states have similar character: have non-zero electric charge and decay into ordinary charmonia and +. The current options for their nature include tetraquark, 22 Back-up slides

23 K-+c1 Dalitz Plot Formalism The decay BKc1 is described by 6 variables, M(c1), M(K), helicity angles c1, J/ and angles btw the production and Integrate over all angles; reconstruction decay planes c1, J/ Fitting function: efficiency is uniform over full angle ranges and interference terms between different c1 helicity states are negligibly small. Amplitude for BKc1 via 2-body

intermediate res.R and c1 in hel. Angle dependent term: Signal event density 24 M(K) description in BK+c1 M(K) description in BK+ 25 Cross-Check: angular distributions + K+ the c1 and J/ M(Kof ) description

in Bin KB c1 Data and predictions from the default fit model agree very well and little discrimination between spin 0 and 1 26 M(K) description in BK+ 27 Results of Dalitz Plot fit with two Zs in BK+

Significance of two Zs over one Z is 3.9 Preliminary 28 Dalitz Plot efficiency in BK+c1 29