D and Ds Hadronic Branching Fractions at B Factories Page: 1 of 8
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D and Ds hadronic branching fractions at B factories
M. Pappagallo(on behalf of the B4B4? Collaboration)
University of Bari and I.N.FN., 70126 Bari, Italy
Recent measurements of hadronic branching fractions of D and D. mesons, performed by the BABAR and Belle
experiments at the asymmetric e+e- B factories colliders PEP II and KEKB, are reviewed.
Hadronic branching fractions of D and D, decays
are used as references mode in many measurements of
branching fractions of D and B-meson decays as well.
A precise measurement of such values improves our
knowledge of D and B-meson properties, and of fun-
damental parameters of the Standard Model, such as
the magnitude of the Cabibbo-Kobayashi-Maskawa 
2. Absolute branching fraction of
Do - K -+
BABAR collaboration measures the absolute branch-
ing fraction B(Do -> K-r+)l using Do -> K-r+
decays in a sample of D0 mesons preselected by their
production in D*+ decays, obtained with partial re-
construction of the decay B0 -> D*+Xf-t, with
D*+ - D0r+ . Such measurement is extremely
important because many of the past and current D
and B branching fraction measurements are indeed
systematically limited by the precision of B(D0 -
A sample of partially reconstructed B mesons in
the channel B0 -> D*+Xf-t is selected by retaining
events containing a charged lepton (f e, p) and a
low momentum pion (soft pion, or) which may arise
from the decay D*+ - D07rf . This sample of events
is referred to as the "inclusive sample".
Using conservation of momentum and energy, the
invariant mass squared of the undetected neutrino is
My (Ebeam ED* EF)2 (D* -+&)2,
where Ebeam is half the total center-of-mass energy,
Et (ED* ), it (iD*) are the energy and momentum
of the lepton (the D* meson) and the magnitude of
the B meson momentum, pB, is considered negligible
compared to pt and PD*. Figure 1 shows the M2 dis-
tribution and the results of a minimum X2 fit aiming
to determine the signal and background contribution.
'Charge conjugation is implied through the paper.
The number of signal events with Mv > -2 GeV2/c4
results Nincl = (2170.64 3.04(stat) 18.1(syst)) x 103.
-10 -8 -6 -4 2-2 0 2 42
Figure 1: The M distribution of the inclusive sample, for
right-charge (a) and wrong-charge (b) samples. The data
are represented by solid points with error. The MC fit
results are overlaid to the data, as explained in the figure.
The D0 -> K--r+ decays in the inclusive sam-
ple are selected requiring events in the mass range
1.82 < MK, < 1.91 GeV/c2 and 142.4 < AM < 149.9
MeV/c2 where AM M(K-r+x<)-M(K-r+) and
7j is the slow pion from D*+ decay. The exclusive se-
lection yields NexCl 33810 290 signal events, where
the error is statistical only.
The branching fraction is computed as
(D K + NincE
where e(K- +) is the D0 reconstruction efficiency as
computed in the simulation, and ( is the selection bias
introduced by the partial reconstruction.
The main systematic uncertainty on Ninca and Nexcl
are respectively due to the non-peaking combinatorial
BB background and the charged-track reconstruction
efficiency. The complete set of systematic uncertain-
ties is listed in Tab. I. The absolute branching fraction
of D0 -> K--r+ decay results
13(D0 - K--r+) (4.007 0.037 0.070)%,
Contributed to International Workshop on Charm Physics (Charm 2007), 8/5/2007-8/8/2007, Ithaca, NY, USA
Work supported in part by US Department of Energy contract DE-AC02-76SF00515
D 9 -> D*IV (a)
other Peakingob nttn u
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Pappagallo, Marco. D and Ds Hadronic Branching Fractions at B Factories, article, January 7, 2008; [Menlo Park, California]. (digital.library.unt.edu/ark:/67531/metadc898142/m1/1/: accessed February 19, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.