Outline: Absolute Charm Branching Fractions D0 and D+ Rare and inclusive modes Final states with KS or KL. Anders Ryd Cornell University Presented at

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1 Determination of Hadronic Branching Ratios and New Modes Anders Ryd Cornell University Presented at FPCP Bled, Slovenia May 12-16, 2007 Outline: Absolute Charm Branching Fractions D0 and D+ Ds Rare and inclusive modes Final states with KS or KL Page: 1

2 Absolute Hadronic D0 and D+ Branching Fractions Important to establish the branching fraction scale Directly impact determination of e.g. Vcb from exclusive modes Need to 'count' the number of produced D mesons Different techniques used _ Y(4S) cc-threshold - K - D e+ - 0 B e- '' e+ D+ D*- D0 e- B0 Tag by full reconstruction of one D l+ + Tag by partial reconstruction of lepton and slow pion (works only for D0) Page: 2

3 CLEO-c Hadronic BrFr. Use a 'double tag' technique, pioneered by MARK III N i= i Bi N D D N j = j B j N D D N ij = ij B i B j N D D N D D= N i N j ij N ij i j N ij j Bi = N j ij The following final states are used D0: K- +, K- + 0, and K D+: K- + +, Ks +, K- 0, KS _+, KS 0, and K-K+ + Determine separately the D and D yields 18 single tag yields 45 (=32+62) double tag yields _ In a combined 2 fit we extract 9 branching fractions and D0D0 and D+D- yields. The fit includes the _ systematic errors. Many systematics cancel in the DD yield (e.g. tracking eff., PID eff.). 56 pb-1 (PRL 96, ) Page: 3

4 Single Tag Yields (281 pb-1) Extract yields from 2 m BC= Ebeam PD2 ~52k ~80k ~26k ~101k ~26k ~16k ~78k ~11k ~7k Lineshape includes Detector resolution ISR in e+e- (3770) (3770) lineshape Beam energy spread Linear scale D+ K- 2 2 E p beam D Page: 4

5 MBC(D0) GeV Double Tag Yields (281 pb-1) _ D+ K + + vs. D- K events (~8600 D+Dtags in total) Data D0D0 ~13600 events MBC(D0) GeV Very clean signals in fully reconstructed events The statistical errors on the double tag yields set the scale of errors on the branching fractions Page: 5

6 Preliminary Results for 281 pb-1 Page: 6

7 BABAR arxiv: fb-1 D K With (K )=39.96% Wrong-charge B(D0 K- Page: 7

8 D K Summary Systematics limited: Statistical: ~1% Systematic: % Many systematic uncertainties at 1% level Some uncertainties that are determined in data will improve with more statistics, e.g., tracking efficiencies and particle identification. CLEO-c doubly double Cabibbo suppressed decays Final state radiation is a 2-3% effect, rely on MC simulations. BABAR needs to understand background shapes very well. Page: 8

9 CLEO-c Ds Branching Fractions Use same technique as for the D0 and D+ branching fractions Pairs of Ds and Ds* Used 195 pb-1 of data e+ recorded at (or near) Ecm=4170 MeV We study the final states: KSK+ - K+ Ds- e- Ds+ Ds*+ K+K- + K+K ' + Take DsDs* data at 4170 Page: 9

10 -1 Single Tag Yields (195 pb ) Mode DS+ DS- K sk ±39 928±37 K + K - π+ 4316± ±89 K+K-π+π 1160± ±84 π+π-π+ 970±80 947±78 ηπ+ 547±50 570±50 η'π+ 362±23 372±24 Page: 10

11 Double Tag Yields 471 signal events Yields from cut-andcount in blue signal region Page: 11

12 Ds Hadronic Branching Fractions Pr eli m in ar y Analysis is statistics limited We have 300 pb-1 on tape Final results this summer Plan to take ~300 pb-1 before CLEO-c running ends Page: 12

13 Belle Ds+ K+K- Using 0.55 ab-1 Belle partially reconstructs e+e- Ds*Ds1 N(Ds*+)=N(e+e- Ds*Ds1) (Ds,,K)Br(Ds) D*- D*- + K Ds1- e+ Ds+ K+ Ds1- eds*+ N(Ds1-)=N(e+e- Ds*Ds1) (D*,,K)Br(D*) e+ eds+ Ds*+ Page: 13

14 Belle Ds KK _ Ds1 D*0K _ Ds1 D*0K Ds1 D*-KS Ds1 D*-KS 45 8 B(Ds+ - CLEO-c (preliminary): B(Ds+ - Page: 14

15 BABAR Ds Using B D*Ds* BABAR has previously measured PRD (2005) B(Ds Using events in which one B meson is fully reconstructed and and either a D(*) or D(*)s(J) is reconstructed they use a missing mass technique to identify the final states Ds arxiv:hep-ex/ v fb-1 B + e D S Btag e- 290,000 B0 tags 463,000 B+ tags Page: 15

16 BABAR Ds Recoil mass against D or D* Recoil mass against Ds or Ds* Page: 16

17 What about Ds The resonance is not well defined Ds interferes with Ds f0 B(Ds ) is not well defined and CLEO-c are not quoting it. We calculate a partial br. fr. in a mkk window around the mass A detailed Dalitz study needed to separate out the Ds fit fractions Ds Κ+Κ π+ partial BF: CLEO-c (±10 MeV around φ) 1.98±0.12±0.09 CLEO-c (±20 MeV around φ) 2.25±0.13±0.12 (Preliminary) For reference: Ds φπ+ PDG06: 4.4±0.6 BaBar: 4.62±0.38±0.50 (1.008<M(K+K-)<1.035 GeV) CLEO-c 195 pb-1 CLEO-c 195 pb-1 f0 Page: 17

18 Inclusive, ', and Production in D and Ds Decays at CLEO c Tag one D or Ds and look at rest of event 281 pb-1 for D0 and D+ 195 pb-1 for Ds As expected, we see that the production of, ', and is larger in Ds decays than in D decays. Important branching fractions for studying Bs decays. B η (%) PDG D0 9.5 ± 0.4 ± 0.8 <13% D+ 6.3 ± 0.5 ± 0.5 <13% Ds ± 3.1 ± 2.0 B - η (%) PDG D ± 0.17± D ± 0.16± Ds+ 8.7 ± 1.9 ± φ (%) PDG B D ± 0.08± ± 0.8 D ± 0.10±0.07 <1.8 Ds ± 1.2 ±1.1 - Page: 18

19 D+ K+ 0 CLEO-c and BABAR has measured this doubly Cabibbo suppressed decay Normalize to D+ K- + + CLEO-c (281 pb-1) BaBar (124 fb-1) Yield = 148±23 B(D K π )= (2.24±0.36 ±0.15±0.08)x B(D+ K+π0)= (2.52±0.46 ±0.24±0.08) x 10-4 Page: 19

20 D KS and D KL It is often assumed that (D KSX)= (D KLX), but this is not strictly true due to interference effects. c s w+ D0 d u u u K0 π0 The physical states of the KS and KL have different rates due to interference Cabibbo-allowed c d w+ D0 s u u u K0 π0 Cabibbo-suppressed Based on factorization Bigi and Yamamoto (PLB 349, 363 (1995)) Predict Page: 20

21 P 0 0 Measuring D KL relimin ary CLEO-c is uniquely positioned to measure D0 KL 0 In tagged events, look at recoil against 0 and veto KS Correcting for Quantum Correlations B D 0 K 0L 0 = 0.940±0.046±0.032 % B D 0 K 0S 0 = 1.212±0.016±0.039 % D 0 K S D0 K L 0 0 D K S D K L =0.122±0.024±0.030 In agreement with theory (factorization) Page: 21

22 Prel D+ KL vs. D+ KS Look for recoil mass against pion in tagged events Missing Mass Squared Missing Mass Squared Yield Efficency BF (%) KS,Lπ+ 4428± ± ±0.056 KLπ+ 2023± ± ±0.040 R D = D + K S D + K L + + D K S D K L ary Extra trk/π0 Veto (removes most Ks) No Veto + imin =0.030±0.023±0.025 Dao-Neng Gao arxiv:hep-ph/ v2 Predicts: R(D+)=0.035 to Page: 22

23 Conclusion For D0 mesons new measurements from both Y(4S) and the (3770) are making improvements to the understanding of the absolute branching fractions. Systematics are limiting the measurements at both energies now. For the D+ branching fractions measured with tags at the (3770) provides the cleanest measurements. Also limited by systematics. The Ds branching fractions at CLEO are not yet systematics limited. The clean environment at CLEO allows studies of modes with KL. Page: 23

24 Backup Slides Page: 24

25 Tracking Efficiencies Events that can be fully reconstructed can be used for very clean studies of tracking efficiencies Look at recoil mass against D0-tag and pion see how often kaon is found In data we find =( )% Kaon found Kaon not found Page: 25

26 Results from 56 pb-1 (PRL 95, ) Our branching fractions are corrected for FSR (so they include 's) -1 Using our measured luminosity of 55.8±0.6 pb we obtain: + + e + e D0 D 0 = 3.60±0.07±0.07 nb e e D D = 2.79±0.07±0.10 nb e + e D D = 6.39±0.10±0.17 nb CLEO-c inclusive: e + e 3770 hadrons = 6.38± nb 0.30 Page: 26

27 BABAR Systematics Page: 27

28 Quantum Correlations PRD (2006) Asner and Sun The two D0 mesons are correlated: C=-1 f f_ l+ RM (1+r2(2-z2)) CP + CP - Correction to BR as compared to incoherent decay 2 R M = x 2 y 2 /2 1+r (2-z ) l- 1 1 CP + 1+rz 1 0 CP - 1-rz X 1+rzy 1 1-y 1+y 2 m y= f 2 x= r ei = D0 K D K z =2cos For CP vs CP eigenstates the correlation is a large effect E.g the decay D0 KS 0 where the other D decays generically (single tag) N D0 K S0 0 =2ND D B D0 K S0 0 1 y 0 0 Where the other D is a flavor tag D f N D0 K S0 0 =ND D B D0 K S r f cos f 0 0 Page: 28