1. The CLEO Collaboration
B Meson Decays to Charm
Sheldon Stone
Syracuse University
USA
Representing
The CLEO Collaboration

2. Introduction
Understanding hadronic B decays is crucial to insuring that that decay modes used for measurement of CP violation truly reflect the underlying quark decay mechanisms expected theoretically
Yet only ~12% of the B decay rate into hadrons has been measured. This includes J/y K(*), D(*)Ds(*) and D(*)(np)-, 3 n 1
Here p-, r- and a1- dominate (quasi-two-body)
Since the averaged charged multiplicity in hadronic B decays is 5.8±0.1, where 2.9±0.1 comes from the D(*), we expect a large decay rate for 3 charged and 1 neutral pion (4p)-

3. The D*+p+p-p-po Final State
(a) DE sidebands
|3.0 – 5.0 s|
(b) DE around 0 ±2.0s fit with sideband shape fixed & norm allowed to float
Also signals in DoK-+ o and DoK-+ + - (not shown)
Fit B yield in bins of M(4p)
DoK-+
35829

4. The p+p- po Mass Distribution
What are the decay mechanisms for the (4p)- final state?
We examine the p+p-po mass spectrum (2 combinations/event). All 3 Do decay modes summed
Enlarged & Dalitz
plot exterior removed

5. The wp- Mass Distribution
Fit MB distribution in wp mass bins
D*wp-
D*+wp-
Breit-Wigner:
Mass = 1367±75
 = 439±135MeV
Mass = 1432±37
 = 376±47MeV
only DoK-+
All 3 Do
decays used
We also observed the omega pion enhancement at around 1400 MeV. What you see here are for charge and neutral D*, where in left plots, three D modes add together. Fitted with simple Breit-Wigner function, we get mass to be 1419 and width is close to 400 MeV.
Possible resonance (A) at M=141933 MeV, =38244 MeV

6. D*+(wp)- Angular Distributions
For a spin-0 A the D* & w would be fully polarized
Spin 0  c2/dof = 3.5 (cosqD*), 22 (cosqw)  Ruled out
Best fit  GL/G = 0.630.09 (D*+), 0.100.09 (w)
Spin-0 expectation
In order to identify this omega pion resonance, we performed angular study. Here only D*+ mode is shown.
What you see are distributions of theta D* and theta omega. The D* decay angle theta d* is defined as the angle between D in D* rest frame to D* boost. Similarly, theta omega is omega decay angle. These two distributions are efficiency corrected.
Both D* and omega are spin-1 particle. We perform a fit to determine its polarization. We get the longitudinal ratio to be 0.63, while omega is consistent with fully transverse polarization.
If omega pion resonance is spin-0, then both D* and omega are fully longitudinally polarized shown in red curve. They don’t agree with data, with chi2 to be 3.5 and 22 respectively. Thus we ruled out spin 0. We can not go further, since D* is spin-1. The angular study is quite complicated. In D case, it will be relative easier.

7. The Dwp- Final State D+wp- Dwp- 8814 9118
only D+K+- -
only DoK-+
Here are B mass spectra for the two modes. Shown on top are for energy side band, and bottom for signal.
We use ARGUS background function to fit side band spectrum. And in signal spectrum, we keep the shape from sideband and let overall scale floating. We use 2.7 MeV for signal width. For D0, we get 88 signals. And for charged D, we get similar number with much higher background.
Signal: |DE|<2s (18MeV) Sideband: 3s<|DE|<7s
No signal in w sidebands

8. The wp- Mass Distribution
Fit MB distribution in wp mass bins
Breit-Wigner:
Mass = 141543
=419110 MeV
In omega pion invariant mass spectrum, we see similar structure as in D* modes. What you seen here are dots for signal, solid and dotted lines for mass and energy sideband respectively. And the bin content of right plot is derived from fit of B mass spectrum in each bin. So it is, sort of, background free. With a simple Breit-Wigner fit, we get similar mass and width. For angular study, we consider only candidates from 1.1 – 1.7 GeV.
Combined Dwp- and D+wp- modes (179 events)
Consistent with D*wp result
Select ( GeV) for angular study (104 events)

9. The Angular Distributions in B  D A-: A-  w p- , w  pp+ p-
 between w in A frame & A boost direction
 between normal of w
decay plane & w boost
 between A & w decay planes
After the correction, the measurement are shown as dot with error bar. Colored curves are the expectations for different spin-parity assumptions. For 1+ and 2-, the longitudinal ratio is floating but consistent in all three fits.
The most interesting one is 1- which is in blue. You can see it is most favored. And 2+ which differs only in first plot as megenda.
Small efficiency corrections applied
For 1+ and 2-, the longitudinal ratio (GL/G) floats
1- preferred, c2/dof (1-) = 1.7, (2+) = 3.2
A- properties: mass = 14182619 MeV, G=3884132 MeV

10. Identifying the A- with the r
Clegg & Donnachie: (t(4p)n, e+e-p+p-, p+p+p-p-) find two 1- states with (M, G)= (146325, 31162) MeV & (173030, 400100) MeV, mixed with non-qq states, only the lighter one decays to wp
Godfrey & Isgur: Predict first radial excited r at MeV, G=320 MeV, B (wp)=39%
So what is it?
Well, between 1 – 2 GeV, a rich variety of states are expected. And they are not well studied due to limited statistics and wide width.
Clegg and Donnachie reviewed datum of tau to 4pi nu, electron positron annihilate to 2 pion or 4 pion, including omega pi data. Their best explanation is that there are two wide 1- states. Only the lighter one decays into omega pi, this is quite consistent with what we observed. However, the situation is very complex. They conclude that these states must be mixed with non qqbar states.
Godfrey and Isgur predicte that the first radial excited rho at 1450 MeV, 320MeV wide and branching ratio to omega pi is close to 40%.
CLEO tau to omega pi nu analysis established that 1- states exist in the same region. The mass and width are fitted but they are model dependent.
Since we observed a wide 1- state in the mass region where the rho’ is expected, the most natural explanation is that for the first time we observe rho’ in B decays.

11. Evidence for r from t Decay
t-wp-n
t-pop-n
CLEO
CLEO r r’
w signal
w sidebands
Difficult to ascertain the Mass and Width

12. Summary & Discussion of Rates
r dominates the wp final state
G(BD) / G(BD) = 1.040.210.06
G(BD) / G(BD) = 1.100.310.06
G(BD) / G(BD) = 1.060.170.04
Consistent with Heavy Quark Symmetry prediction ( ratio = 1 )
With B (wp)=39%, G(BD(*)) ~ G(BD(*))
I listed here all the branching ratios we measured. I want to point out two interesting thing in this table.
First, the branching ratios of B to D omega pion quite close to D*omega pion, doesn’t matter if it is neutal D or charged D. As rho’ dominate omega pi final state. The ratio also represents that of D rho’. They are quite close to 1 for charged D and neutral D, and average. This is consistent with heavy quark symmetry, which predicate equal partial width.
Second, if we take the predicted branching ratio of 39%, the branching ratio of B to D D* rho’ is close to B to D D* rho.

13. Factorization Tests Using Polarization
GL/G (BD+h) = GL/G (BD+ln )|q2=mh2
Also use new BoD+Ds-, & old D+r data 
Final State
B(%)
D+Ds-
1.100.180.100.28
D+Ds -
1.820.370.240.46
D()+Ds**o
2.730.780.480.68 *
(Determined using
partial reconstruction)
D*+ +
GL/G (%) r-
87.85.3
r-
63  9
DS-
50.613.93.6 *

14. Using Factorization
G(BD+h) / dG/dq2 (BD+ln )|q2=mh2 = 6p2c12fh2 |Vud|2, c1=1.1±0.1
Measurement:
f2 B (wp) = ± GeV2
Godfrey & Isgur predict:
B (wp)=39%
Our measurment  f = 167 ± 23MeV
We also test factorization. The polarization is a very sensitive test. Factorization expect that the polarization ratio of D* in B to D*+ and a light meson is the same as that of B to D* l nu at the point where l nu invariant mass equal to light meson mass. We measured Longitudinal ratio to be 63%. Because there is no polarization measurement in D* l nu data, we use model predicated value. The predicted value various between 67 to 73%. They are consistent with the measurement.
The factorization also predict the branching ratio of B to D*+ plus a light meson is strongly correlated to differential branching ratio of B to D* l nu. Here c1 is QCD correction factor and f is decay constant of light meson.
As rho’ is poorly studied, we have neither the decay constant nor the branching ratio. Using factorization predication, we can get the product of these two parameter. Godfrey and Isgur predict the decay constant to be 80 MeV and branching ratio is 39%. As they indicated, f can vary by a factor of 2. But the branching ratio should be quite close to reality. If we use this branching ratio. We derived that f rho’ is 167MeV, much bigger than their expectation.

15. Potpourri of Results Using Exclusive Charmonium Decays
Y(4S) branching fractions using BJ/yK(*)
Yields: foo=0.490.020.01, f+-=0.510.020.01
Yields, using factorization fh = 33575 MeV
No CP asymmetry observed in c

16. Conclusions
Large ~ 1.8% branching rate D*p+p-p-po modes have been found
r seen for first time in B decays (hep-ex/ )
Coupling large, may be similar to r
Relatively clean place to establish rmass and width, we find M=1418±26±19 MeV, G=388±44±32 MeV
Factorization tests involving spin symmetry and polarization work for D*+r , r, and DS-
Ratio of charged/neutral B production at Y(4S) nearly equal.
No anomalies in charmonium decays found
No unexpected large CP asymmetries in y()K
“Reasonable” rate for hCK final states ~J/y K *