of 7
Measurement of the Branching Fractions of

B
!
D




Decays in Events Tagged
by a Fully Reconstructed
B
Meson
B. Aubert,
1
M. Bona,
1
Y. Karyotakis,
1
J. P. Lees,
1
V. Poireau,
1
E. Prencipe,
1
X. Prudent,
1
V. Tisserand,
1
J. Garra Tico,
2
E. Grauges,
2
L. Lopez,
3a,3b
A. Palano,
3a,3b
M. Pappagallo,
3a,3b
G. Eigen,
4
B. Stugu,
4
L. Sun,
4
G. S. Abrams,
5
M. Battaglia,
5
D. N. Brown,
5
R. N. Cahn,
5
R. G. Jacobsen,
5
L. T. Kerth,
4
Yu. G. Kolomensky,
5
G. Lynch,
5
I. L. Osipenkov,
5
M. T. Ronan,
5,
*
K. Tackmann,
5
T. Tanabe,
5
C. M. Hawkes,
6
N. Soni,
6
A. T. Watson,
6
H. Koch,
7
T. Schroeder,
7
D. Walker,
8
D. J. Asgeirsson,
9
B. G. Fulsom,
9
C. Hearty,
9
T. S. Mattison,
9
J. A. McKenna,
9
M. Barrett,
10
A. Khan,
10
V. E. Blinov,
11
A. D. Bukin,
11
A. R. Buzykaev,
11
V. P. Druzhinin,
11
V. B. Golubev,
11
A. P. Onuchin,
11
S. I. Serednyakov,
11
Yu. I. Skovpen,
11
E. P. Solodov,
11
K. Yu. Todyshev,
11
M. Bondioli,
12
S. Curry,
12
I. Eschrich,
12
D. Kirkby,
12
A. J. Lankford,
12
P. Lund,
12
M. Mandelkern,
12
E. C. Martin,
12
D. P. Stoker,
12
S. Abachi,
13
C. Buchanan,
13
J. W. Gary,
14
F. Liu,
14
O. Long,
14
B. C. Shen,
14,
*
G. M. Vitug,
14
Z. Yasin,
14
L. Zhang,
14
V. Sharma,
15
C. Campagnari,
16
T. M. Hong,
16
D. Kovalskyi,
16
M. A. Mazur,
16
J. D. Richman,
16
T. W. Beck,
17
A. M. Eisner,
17
C. J. Flacco,
17
C. A. Heusch,
17
J. Kroseberg,
17
W. S. Lockman,
17
T. Schalk,
17
B. A. Schumm,
17
A. Seiden,
17
L. Wang,
17
M. G. Wilson,
17
L. O. Winstrom,
17
C. H. Cheng,
18
D. A. Doll,
18
B. Echenard,
18
F. Fang,
18
D. G. Hitlin,
18
I. Narsky,
18
T. Piatenko,
18
F. C. Porter,
18
R. Andreassen,
19
G. Mancinelli,
19
B. T. Meadows,
19
K. Mishra,
19
M. D. Sokoloff,
19
P. C. Bloom,
20
W. T. Ford,
20
A. Gaz,
20
J. F. Hirschauer,
20
M. Nagel,
20
U. Nauenberg,
20
J. G. Smith,
20
K. A. Ulmer,
20
S. R. Wagner,
20
R. Ayad,
20
A. Soffer,
21,
W. H. Toki,
21,
R. J. Wilson,
21
D. D. Altenburg,
22
E. Feltresi,
22
A. Hauke,
22
H. Jasper,
22
M. Karbach,
22
J. Merkel,
22
A. Petzold,
22
B. Spaan,
22
K. Wacker,
22
M. J. Kobel,
23
W. F. Mader,
23
R. Nogowski,
23
K. R. Schubert,
23
R. Schwierz,
23
J. E. Sundermann,
23
A. Volk,
23
D. Bernard,
24
G. R. Bonneaud,
24
E. Latour,
24
Ch. Thiebaux,
24
M. Verderi,
24
P. J. Clark,
25
W. Gradl,
25
S. Playfer,
25
J. E. Watson,
25
M. Andreotti,
26a,26b
D. Bettoni,
26a
C. Bozzi,
26a
R. Calabrese,
26a,26b
A. Cecchi,
26a,26b
G. Cibinetto,
26a,26b
P. Franchini,
26a,26b
E. Luppi,
26a,26b
M. Negrini,
26a,26b
A. Petrella,
26a,26b
L. Piemontese,
26a
V. Santoro,
26a,26b
R. Baldini-Ferroli,
27
A. Calcaterra,
27
R. de Sangro,
27
G. Finocchiaro,
27
S. Pacetti,
27
P. Patteri,
27
I. M. Peruzzi,
27,
x
M. Piccolo,
27
M. Rama,
27
A. Zallo,
27
A. Buzzo,
28a
R. Contri,
28a,28b
M. Lo Vetere,
28a,28b
M. M. Macri,
28a
M. R. Monge,
28a,28b
S. Passaggio,
28a
C. Patrignani,
28a,28b
E. Robutti,
28a
A. Santroni,
28a,28b
S. Tosi,
28a,28b
K. S. Chaisanguanthum,
29
M. Morii,
29
J. Marks,
30
S. Schenk,
30
U. Uwer,
30
V. Klose,
31
H. M. Lacker,
31
D. J. Bard,
32
P. D. Dauncey,
32
J. A. Nash,
32
W. Panduro Vazquez,
32
M. Tibbetts,
32
P. K. Behera,
33
X. Chai,
33
M. J. Charles,
33
U. Mallik,
33
J. Cochran,
34
H. B. Crawley,
34
L. Dong,
34
W. T. Meyer,
34
S. Prell,
34
E. I. Rosenberg,
34
A. E. Rubin,
34
Y. Y. Gao,
35
A. V. Gritsan,
35
Z. J. Guo,
35
C. K. Lae,
35
A. G. Denig,
36
M. Fritsch,
36
G. Schott,
36
N. Arnaud,
37
J. Be
́
quilleux,
37
A. D’Orazio,
37
M. Davier,
37
J. Firmino da Costa,
37
G. Grosdidier,
37
A. Ho
̈
cker,
37
V. Lepeltier,
37
F. Le Diberder,
37
A. M. Lutz,
37
S. Pruvot,
37
P. Roudeau,
37
M. H. Schune,
37
J. Serrano,
37
V. Sordini,
37,
k
A. Stocchi,
37
G. Wormser,
37
D. J. Lange,
38
D. M. Wright,
38
I. Bingham,
39
J. P. Burke,
39
C. A. Chavez,
39
J. R. Fry,
39
E. Gabathuler,
39
R. Gamet,
39
D. E. Hutchcroft,
39
D. J. Payne,
39
C. Touramanis,
39
A. J. Bevan,
40
C. K. Clarke,
40
K. A. George,
40
F. Di Lodovico,
40
R. Sacco,
40
M. Sigamani,
40
G. Cowan,
41
H. U. Flaecher,
41
D. A. Hopkins,
41
S. Paramesvaran,
41
F. Salvatore,
41
A. C. Wren,
41
D. N. Brown,
42
C. L. Davis,
42
K. E. Alwyn,
43
D. Bailey,
43
R. J. Barlow,
43
Y. M. Chia,
43
C. L. Edgar,
43
G. Jackson,
43
G. D. Lafferty,
43
T. J. West,
43
J. I. Yi,
43
J. Anderson,
44
C. Chen,
44
A. Jawahery,
44
D. A. Roberts,
44
G. Simi,
44
J. M. Tuggle,
44
C. Dallapiccola,
45
X. Li,
45
E. Salvati,
45
S. Saremi,
45
R. Cowan,
46
D. Dujmic,
46
P. H. Fisher,
46
K. Koeneke,
46
G. Sciolla,
46
M. Spitznagel,
46
F. Taylor,
46
R. K. Yamamoto,
46
M. Zhao,
46
P. M. Patel,
47
S. H. Robertson,
47
A. Lazzaro,
48a,48b
V. Lombardo,
48a
F. Palombo,
48a,48b
J. M. Bauer,
49
L. Cremaldi,
49
V. Eschenburg,
49
R. Godang,
49,
{
R. Kroeger,
49
D. A. Sanders,
49
D. J. Summers,
49
H. W. Zhao,
49
M. Simard,
50
P. Taras,
50
F. B. Viaud,
50
H. Nicholson,
51
G. De Nardo,
52a,52b
L. Lista,
52a
D. Monorchio,
52a,52b
G. Onorato,
52a,52b
C. Sciacca,
52a,52b
G. Raven,
53
H. L. Snoek,
53
C. P. Jessop,
54
K. J. Knoepfel,
54
J. M. Lo Secco,
54
W. F. Wang,
54
G. Benelli,
55
L. A. Corwin,
55
K. Honscheid,
55
H. Kagan,
55
R. Kass,
55
J. P. Morris,
55
A. M. Rahimi,
55
J. J. Regensburger,
55
S. J. Sekula,
55
Q. K. Wong,
55
N. L. Blount,
56
J. Brau,
56
R. Frey,
56
O. Igonkina,
56
J. A. Kolb,
56
M. Lu,
56
R. Rahmat,
56
N. B. Sinev,
56
D. Strom,
56
J. Strube,
56
E. Torrence,
56
G. Castelli,
57a,57b
N. Gagliardi,
57a,57b
M. Margoni,
57a,57b
M. Morandin,
57a
M. Posocco,
57a
M. Rotondo,
57a
F. Simonetto,
57a,57b
R. Stroili,
57a,57b
C. Voci,
57a,57b
P. del Amo Sanchez,
58
E. Ben-Haim,
58
H. Briand,
58
G. Calderini,
58
J. Chauveau,
58
P. David,
58
L. Del Buono,
58
O. Hamon,
58
Ph. Leruste,
58
J. Ocariz,
58
A. Perez,
58
J. Prendki,
58
S. Sitt,
58
L. Gladney,
59
M. Biasini,
60a,60b
R. Covarelli,
60a,60b
E. Manoni,
60a,60b
C. Angelini,
61a,61b
G. Batignani,
61a,61b
S. Bettarini,
61a,61b
M. Carpinelli,
61a,61b,
**
A. Cervelli,
61a,61b
F. Forti,
61a,61b
M. A. Giorgi,
61a,61b
A. Lusiani,
61a,61c
G. Marchiori,
61a,61b
M. Morganti,
61a,61b
N. Neri,
61a,61b
E. Paoloni,
61a,61b
G. Rizzo,
61a,61b
J. J. Walsh,
61a
D. Lopes Pegna,
62
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
0031-9007
=
08
=
101(26)
=
261802(7)
261802-1
Ó
2008 The American Physical Society
C. Lu,
62
J. Olsen,
62
A. J. S. Smith,
62
A. V. Telnov,
62
F. Anulli,
63a
E. Baracchini,
63a,63b
G. Cavoto,
63a
D. del Re,
63a,63b
E. Di Marco,
63a,63b
R. Faccini,
63a,63b
F. Ferrarotto,
63a
F. Ferroni,
63a,63b
M. Gaspero,
63a,63b
P. D. Jackson,
63a
L. Li Gioi,
63a
M. A. Mazzoni,
63a
S. Morganti,
63a
G. Piredda,
63a
F. Polci,
63a,63b
F. Renga,
63a,63b
C. Voena,
63a
M. Ebert,
64
T. Hartmann,
64
H. Schro
̈
der,
64
R. Waldi,
64
T. Adye,
65
B. Franek,
65
E. O. Olaiya,
65
F. F. Wilson,
65
S. Emery,
66
M. Escalier,
66
L. Esteve,
66
S. F. Ganzhur,
66
G. Hamel de Monchenault,
66
W. Kozanecki,
66
G. Vasseur,
66
Ch. Ye
`
che,
66
M. Zito,
66
X. R. Chen,
67
H. Liu,
67
W. Park,
67
M. V. Purohit,
67
R. M. White,
67
J. R. Wilson,
67
M. T. Allen,
68
D. Aston,
68
R. Bartoldus,
68
P. Bechtle,
68
J. F. Benitez,
68
R. Cenci,
68
J. P. Coleman,
68
M. R. Convery,
68
J. C. Dingfelder,
68
J. Dorfan,
68
G. P. Dubois-Felsmann,
68
W. Dunwoodie,
68
R. C. Field,
68
A. M. Gabareen,
68
S. J. Gowdy,
68
M. T. Graham,
68
P. Grenier,
68
C. Hast,
68
W. R. Innes,
68
J. Kaminski,
68
M. H. Kelsey,
68
H. Kim,
68
P. Kim,
68
M. L. Kocian,
68
D. W. G. S. Leith,
68
S. Li,
68
B. Lindquist,
68
S. Luitz,
68
V. Luth,
68
H. L. Lynch,
68
D. B. MacFarlane,
68
H. Marsiske,
68
R. Messner,
68
D. R. Muller,
68
H. Neal,
68
S. Nelson,
68
C. P. O’Grady,
68
I. Ofte,
68
A. Perazzo,
68
M. Perl,
68
B. N. Ratcliff,
68
A. Roodman,
68
A. A. Salnikov,
68
R. H. Schindler,
68
J. Schwiening,
68
A. Snyder,
68
D. Su,
68
M. K. Sullivan,
68
K. Suzuki,
68
S. K. Swain,
68
J. M. Thompson,
68
J. Va’vra,
68
A. P. Wagner,
68
M. Weaver,
68
C. A. West,
68
W. J. Wisniewski,
68
M. Wittgen,
68
D. H. Wright,
68
H. W. Wulsin,
68
A. K. Yarritu,
68
K. Yi,
68
C. C. Young,
68
V. Ziegler,
68
P. R. Burchat,
69
A. J. Edwards,
69
S. A. Majewski,
69
T. S. Miyashita,
69
B. A. Petersen,
69
L. Wilden,
69
S. Ahmed,
70
M. S. Alam,
70
J. A. Ernst,
70
B. Pan,
70
M. A. Saeed,
70
S. B. Zain,
70
S. M. Spanier,
71
B. J. Wogsland,
71
R. Eckmann,
72
J. L. Ritchie,
72
A. M. Ruland,
72
C. J. Schilling,
72
R. F. Schwitters,
72
B. W. Drummond,
73
J. M. Izen,
73
X. C. Lou,
73
F. Bianchi,
74a,74b
D. Gamba,
74a,74b
M. Pelliccioni,
74a,74b
M. Bomben,
75a,75b
L. Bosisio,
75a,75b
C. Cartaro,
75a,75b
G. Della Ricca,
75a,75b
L. Lanceri,
75a,75b
L. Vitale,
75a,75b
V. Azzolini,
76
N. Lopez-March,
76
F. Martinez-Vidal,
76
D. A. Milanes,
76
A. Oyanguren,
76
J. Albert,
77
Sw. Banerjee,
77
B. Bhuyan,
77
H. H. F. Choi,
77
K. Hamano,
77
R. Kowalewski,
77
M. J. Lewczuk,
77
I. M. Nugent,
77
J. M. Roney,
77
R. J. Sobie,
77
T. J. Gershon,
78
P. F. Harrison,
78
J. Ilic,
78
T. E. Latham,
78
G. B. Mohanty,
78
H. R. Band,
79
X. Chen,
79
S. Dasu,
79
K. T. Flood,
79
Y. Pan,
79
M. Pierini,
79
R. Prepost,
79
C. O. Vuosalo,
79
and S. L. Wu
79
(The
B
A
B
AR
Collaboration)
1
Laboratoire de Physique des Particules, IN2P3/CNRS et Universite
́
de Savoie, F-74941 Annecy-Le-Vieux, France
2
Universitat de Barcelona, Facultat de Fisica, Departament ECM, E-08028 Barcelona, Spain
3a
INFN Sezione di Bari, Dipartmento di Fisica, I-70126 Bari, Italy;
3b
Universita
`
di Bari, I-70126 Bari, Italy
4
University of Bergen, Institute of Physics, N-5007 Bergen, Norway
5
Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720, USA
6
University of Birmingham, Birmingham, B15 2TT, United Kingdom
7
Ruhr Universita
̈
t Bochum, Institut fu
̈
r Experimentalphysik 1, D-44780 Bochum, Germany
8
University of Bristol, Bristol BS8 1TL, United Kingdom
9
University of British Columbia, Vancouver, British Columbia, V6T 1Z1 Canada
10
Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
11
Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia
12
University of California at Irvine, Irvine, California 92697, USA
13
University of California at Los Angeles, Los Angeles, California 90024, USA
14
University of California at Riverside, Riverside, California 92521, USA
15
University of California at San Diego, La Jolla, California 92093, USA
16
University of California at Santa Barbara, Santa Barbara, California 93106, USA
17
University of California at Santa Cruz, Institute for Particle Physics, Santa Cruz, California 95064, USA
18
California Institute of Technology, Pasadena, California 91125, USA
19
University of Cincinnati, Cincinnati, Ohio 45221, USA
20
University of Colorado, Boulder, Colorado 80309, USA
21
Colorado State University, Fort Collins, Colorado 80523, USA
22
Technische Universita
̈
t Dortmund, Fakulta
̈
t Physik, D-44221 Dortmund, Germany
23
Technische Universita
̈
t Dresden, Institut fu
̈
r Kern- und Teilchenphysik, D-01062 Dresden, Germany
24
Laboratoire Leprince-Ringuet, CNRS/IN2P3, Ecole Polytechnique, F-91128 Palaiseau, France
25
University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
26a
INFN Sezione di Ferrara, Dipartimento di Fisica, I-44100 Ferrara, Italy
26b
Universita
`
di Ferrara, I-44100 Ferrara, Italy
27
INFN Laboratori Nazionali di Frascati, I-00044 Frascati, Italy
28a
INFN Sezione di Genova, Dipartimento di Fisica, I-16146 Genova, Italy
28b
Universita
`
di Genova, I-16146 Genova, Italy
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-2
29
Harvard University, Cambridge, Massachusetts 02138, USA
30
Universita
̈
t Heidelberg, Physikalisches Institut, Philosophenweg 12, D-69120 Heidelberg, Germany
31
Humboldt-Universita
̈
t zu Berlin, Institut fu
̈
r Physik, Newtonstr. 15, D-12489 Berlin, Germany
32
Imperial College London, London, SW7 2AZ, United Kingdom
33
University of Iowa, Iowa City, Iowa 52242, USA
34
Iowa State University, Ames, Iowa 50011-3160, USA
35
Johns Hopkins University, Baltimore, Maryland 21218, USA
36
Universita
̈
t Karlsruhe, Institut fu
̈
r Experimentelle Kernphysik, D-76021 Karlsruhe, Germany
37
Laboratoire de l’Acce
́
le
́
rateur Line
́
aire, IN2P3/CNRS et Universite
́
Paris-Sud 11, Centre Scientifique d’Orsay,
B. P. 34, F-91898 Orsay Cedex, France
38
Lawrence Livermore National Laboratory, Livermore, California 94550, USA
39
University of Liverpool, Liverpool L69 7ZE, United Kingdom
40
Queen Mary, University of London, London, E1 4NS, United Kingdom
41
University of London, Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, United Kingdom
42
University of Louisville, Louisville, Kentucky 40292, USA
43
University of Manchester, Manchester M13 9PL, United Kingdom
44
University of Maryland, College Park, Maryland 20742, USA
45
University of Massachusetts, Amherst, Massachusetts 01003, USA
46
Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, Massachusetts 02139, USA
47
McGill University, Montre
́
al, Que
́
bec, H3A 2T8, Canada
48a
INFN Sezione di Milano, Dipartimento di Fisica, I-20133 Milano, Italy
48b
Universita
`
di Milano, I-20133 Milano, Italy
49
University of Mississippi, University, Mississippi 38677, USA
50
Universite
́
de Montre
́
al, Physique des Particules, Montre
́
al, Que
́
bec, H3C 3J7, Canada
51
Mount Holyoke College, South Hadley, Massachusetts 01075, USA
52a
INFN Sezione di Napoli, Dipartimento di Scienze Fisiche, I-80126 Napoli, Italy
52b
Universita
`
di Napoli Federico II, I-80126 Napoli, Italy
53
NIKHEF, National Institute for Nuclear Physics and High Energy Physics, NL-1009 DB Amsterdam, The Netherlands
54
University of Notre Dame, Notre Dame, Indiana 46556, USA
55
Ohio State University, Columbus, Ohio 43210, USA
56
University of Oregon, Eugene, Oregon 97403, USA
57a
INFN Sezione di Padova, Dipartimento di Fisica, I-35131 Padova, Italy
57b
Universita
`
di Padova, I-35131 Padova, Italy
58
Laboratoire de Physique Nucle
́
aire et de Hautes Energies, IN2P3/CNRS, Universite
́
Pierre et Marie Curie-Paris 6,
Universite
́
Denis Diderot-Paris 7, F-75252 Paris, France
59
University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
60a
INFN Sezione di Perugia, Dipartimento di Fisica, I-06100 Perugia, Italy
60b
Universita
`
di Perugia, I-06100 Perugia, Italy
61a
INFN Sezione di Pisa, Dipartimento di Fisica, I-56127 Pisa, Italy
61b
Universita
`
di Pisa, I-56127 Pisa, Italy
61c
Scuola Normale Superiore di Pisa, I-56127 Pisa, Italy
62
Princeton University, Princeton, New Jersey 08544, USA
63a
INFN Sezione di Roma, Dipartimento di Fisica, I-00185 Roma, Italy
63b
Universita
`
di Roma La Sapienza, I-00185 Roma, Italy
64
Universita
̈
t Rostock, D-18051 Rostock, Germany
65
Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, United Kingdom
66
DSM/Irfu, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France
67
University of South Carolina, Columbia, South Carolina 29208, USA
68
Stanford Linear Accelerator Center, Stanford, California 94309, USA
69
Stanford University, Stanford, California 94305-4060, USA
70
State University of New York, Albany, New York 12222, USA
71
University of Tennessee, Knoxville, Tennessee 37996, USA
72
University of Texas at Austin, Austin, Texas 78712, USA
73
University of Texas at Dallas, Richardson, Texas 75083, USA
74a
INFN Sezione di Torino, Dipartimento di Fisica Sperimentale, I-10125 Torino, Italy
74b
Universita
`
di Torino, I-10125 Torino, Italy
75a
INFN Sezione di Trieste, Dipartimento di Fisica, I-34127 Trieste, Italy
75b
Universita
`
di Trieste, I-34127 Trieste, Italy
76
IFIC, Universitat de Valencia-CSIC, E-46071 Valencia, Spain
77
University of Victoria, Victoria, British Columbia, V8W 3P6, Canada
78
Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-3
79
University of Wisconsin, Madison, Wisconsin 53706, USA
(Received 4 August 2008; published 23 December 2008)
We report a measurement of the branching fractions of

B
!
D




decays based on
417 fb

1
of data
collected at the

ð
4
S
Þ
resonance with the
BABAR
detector at the PEP-II
e
þ
e

storage rings. Events are
selected by fully reconstructing one of the
B
mesons in a hadronic decay mode. A fit to the invariant mass
differences
m
ð
D
ðÞ

Þ
m
ð
D
ðÞ
Þ
is performed to extract the signal yields of the different
D

states. We
observe the

B
!
D




decay modes corresponding to the four
D

states predicted by heavy quark
symmetry with a significance greater than 5 standard deviations including systematic uncertainties.
DOI:
10.1103/PhysRevLett.101.261802
PACS numbers: 13.20.He, 12.38.Qk, 14.40.Nd
Semileptonic
B
decays to orbitally excited
P
-wave
charm mesons (
D

) are of interest for several reasons.
Improved knowledge of the branching fractions for these
decays is important to reduce the systematic uncertainty in
the measurements of the Cabibbo-Kobayashi-Maskawa [
1
]
matrix elements
j
V
cb
j
and
j
V
ub
j
. For example, one of the
leading sources of systematic uncertainty on
j
V
cb
j
mea-
surements from

B
!
D




decays [
2
] is the limited
knowledge of the background due to

B
!
D




[
3
].
The
D

mesons contain one charm quark and one light
quark with relative angular momentum
L
¼
1
. According
to Heavy Quark Symmetry (HQS) [
4
], they form one
doublet of states with angular momentum
j

s
q
þ
L
¼
3
=
2
½
D
1
ð
2420
Þ
;D

2
ð
2460
Þ
and another doublet with
j
¼
1
=
2
½
D

0
ð
2400
Þ
;D
0
1
ð
2430
Þ
, where
s
q
is the light quark spin.
Parity and angular momentum conservation constrain the
decays allowed for each state. The
D
1
and
D

2
states decay
through a
D
-wave to
D


and
D
ðÞ

, respectively, and
have small decay widths, while the
D

0
and
D
0
1
states decay
through an
S
-wave to
D
and
D


and are very broad.

B
!
D




decays constitute a significant fraction of
B
semileptonic decays [
5
] and may help to explain the
discrepancy between the inclusive

B
!
X‘



rate and the
sum of the measured exclusive decay rates [
5
7
]. The
measured decay properties for

B
!
D




can be com-
pared with the predictions of the Heavy Quark Effective
Theory (HQET) [
8
]. QCD sum rules [
9
] imply the strong
dominance of
B
decays to the narrow
D

states over those
to the wide ones, while some experimental data show the
opposite trend [
10
,
11
].
In this Letter, we present the observation of
B
semi-
leptonic decays into the four excited
D
mesons predicted
by HQS and measure the
B
ð

B
!
D




Þ
branching
fractions. The analysis is based on data collected with the
BABAR
detector [
12
] at the PEP-II asymmetric-energy
e
þ
e

storage rings at SLAC. The data consist of a total
of
417 fb

1
recorded at the

ð
4
S
Þ
resonance, correspond-
ing to approximately
460

10
6
B

B
pairs. An additional
40 fb

1
, taken at a center-of-mass (c.m.) energy 40 MeV
below the

ð
4
S
Þ
resonance, is used to study background
from
e
þ
e

!
f

f
ð
f
¼
u;d;s;c;
Þ
continuum events. A
detailed
GEANT4
-based Monte Carlo (MC) simulation
[
13
]of
B

B
and continuum events is used to study the
detector response, its acceptance, and to validate the analy-
sis techniques. The simulation describes

B
!
D




decays using the ISGW2 model [
14
] and nonresonant

B
!
D
ðÞ
‘



decays using the model of Goity and Roberts
[
15
].
We select semileptonic

B
!
D




decays with
¼
e
,

in events containing a fully reconstructed
B
meson
(
B
tag
), which allows us to constrain the kinematics, reduce
the combinatorial background, and determine the charge
and flavor of the signal
B
meson.
D

mesons are recon-
structed in the
D
ðÞ


decay modes, and the different
D

states are identified by a fit to the invariant mass differ-
ences
m
ð
D
ðÞ

Þ
m
ð
D
ðÞ
Þ
.
We first reconstruct the semileptonic
B
decay, selecting
a lepton with momentum
p

in the c.m. frame larger than
0
:
6 GeV
=c
. We search for pairs of oppositely charged
tracks that form a vertex and remove those with an invari-
ant mass consistent with a photon conversion or a

0
Dalitz
decay. Candidate
D
0
mesons that have the correct charge
correlation with the lepton are reconstructed in the
K


þ
,
K


þ

0
,
K


þ

þ


,
K
0
S

þ


,
K
0
S

þ



0
,
K
0
S

0
,
K
þ
K

,

þ


, and
K
0
S
K
0
S
channels, and
D
þ
mesons in
the
K


þ

þ
,
K


þ

þ

0
,
K
0
S

þ
,
K
0
S

þ

0
,
K
þ
K


þ
,
K
0
S
K
þ
, and
K
0
S

þ

þ


channels. In events with multiple
D‘

combinations, the candidate with the best
D
-
vertex
fit is selected. Candidate
D

mesons are reconstructed by
combining a
D
candidate with a pion or a photon in the
D
!
D
0

þ
,
D
!
D
þ

0
,
D

0
!
D
0

0
, and
D

0
!
D
0

channels. In events with multiple
D


combinations,
we choose the candidate with the smallest

2
based on the
deviations from the nominal values of the
D
invariant mass
and the invariant mass difference between the
D

and the
D
, using the resolution measured in each mode.
We reconstruct
B
tag
decays [
16
] in charmed hadronic
modes

B
!
DY
, where
Y
represents a collection of had-
rons, composed of
n
1


þ
n
2
K

þ
n
3
K
0
S
þ
n
4

0
, where
n
1
þ
n
2
¼
1
,3,5,
n
3

2
, and
n
4

2
. Using
D
0
ð
D
þ
Þ
and
D

0
ð
D
Þ
as seeds for
B

ð

B
0
Þ
decays, we reconstruct
about 1000 different decay chains.
The kinematic consistency of a
B
tag
candidate with a
B
meson decay is evaluated using two variables: the beam-
energy substituted mass
m
ES

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
s=
4
j
p

B
j
2
q
, and the en-
ergy difference

E

E

B

ffiffiffi
s
p
=
2
. Here,
ffiffiffi
s
p
is the total
c.m. energy, and
p

B
and
E

B
denote the momentum and
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-4
energy of the
B
tag
candidate in the c.m. frame. For correctly
identified
B
tag
decays, the
m
ES
distribution peaks at the
B
meson mass, while

E
is consistent with zero. We select
B
tag
candidates in the signal region defined as
5
:
27 GeV
=c
2
<m
ES
<
5
:
29 GeV
=c
2
, excluding those
with daughter particles in common with the charm meson
or the lepton from the semileptonic
B
decay. In the case of
multiple
B
tag
candidates in an event, we select the one with
the smallest
j

E
j
value. The
B
tag
and the
D
ðÞ
candidates
are required to have the correct charge-flavor correlation.
We account for mixing effects in the

B
0
sample as de-
scribed in Ref. [
17
]. Cross-feed effects, i.e.,
B

tag
ð

B
0
tag
Þ
candidates erroneously reconstructed as a neutral
(charged)
B
, are subtracted using estimates from the
simulation.
We reconstruct
B

!
D
ðÞþ





and

B
0
!
D
ðÞ
0

þ



decays starting from the corresponding
B
tag
þ
D
ðÞ

combinations. We select events with only
one additional reconstructed charged track, correctly
matched to the
D
ðÞ
flavor, that has not been used for the
reconstruction of the
B
tag
, the signal
D
ðÞ
, or the lepton.
D
ð
D

Þ
candidates are selected within
2

(
1
:
5
2
:
5

, de-
pending on the
D

decay mode) of the
D
mass (
D


D
mass difference), where the resolution

is typically
around 8
ð
1
7
Þ
MeV
=c
2
. For the

B
0
!
D
ðÞ
0

þ



de-
cay, we additionally require the invariant mass difference
m
ð
D
0

þ
Þ
m
ð
D
0
Þ
to be greater than
0
:
18 GeV
=c
2
to veto

B
0
!
D



events.
Semileptonic

B
!
D




decays are identified by the
missing mass squared in the event,
m
2
miss
¼f
p
½

ð
4
S
Þ
p
ð
B
tag
Þ
p
ð
D
ðÞ

Þ
p
ð
Þg
2
, defined in terms of the par-
ticle four momenta. For correctly reconstructed signal
events, the only missing particle is the neutrino, and
m
2
miss
peaks at zero. Other
B
semileptonic decays, where
one particle is not reconstructed (feed-down) or is erro-
neously added to the charm candidate (feed-up), exhibit
higher or lower values in
m
2
miss
[
7
]. In feed-down cases
where both a
D
and a
D

candidate have been recon-
structed, we keep only the latter candidate.
The
m
2
miss
selection criteria are listed in Table
I
.
The
m
2
miss
region between 0.2 and
1 GeV
2
=c
4
for

B
!
D‘



events is dominated by feed-down from

B
!
D

ð!
D


Þ



semileptonic decays where the soft
pion from the
D

decay is not reconstructed. In order to
retain these events, we apply an asymmetric cut on
m
2
miss
for these modes. As a cross check, we repeat the analysis
using a symmetric cut on
m
2
miss
for each event sample,
obtaining results consistent with the ones presented below.
The signal yields for the

B
!
D




decays are ex-
tracted through a simultaneous unbinned maximum like-
lihood fit to the four
m
ð
D
ðÞ

Þ
m
ð
D
ðÞ
Þ
distributions.
With the current statistics, validation studies on MC
samples show that our sensitivity to nonresonant

B
!
D
ðÞ
‘



decays is limited. Including hypotheses for
these components results in a fitted contribution that is
consistent with zero. Thus, we assume that these nonreso-
nant contributions are negligible. The probability that

B
!
D

ð!
D


Þ



decays are reconstructed as

B
!
D

ð!
D
Þ



is determined with the MC simulation
to be 26%(59%) for the
B

ð

B
0
Þ
sample and held fixed in
the fit.
The Probability Density Functions (PDFs) for the
D

signal components are determined using MC

B
!
D




signal events. A convolution of a Breit-Wigner
function with a Gaussian, whose resolution is determined
from the simulation, is used to model the
D

resonances.
The
D

masses and widths are fixed to measured values
[
5
]. We rely on the MC prediction for the shape of the
combinatorial and continuum background. A nonparamet-
ric KEYS function [
18
] is used to model this component
for the
D

‘



sample, while for the
D‘



sample,
we use the convolution of an exponential with a Gaussian
to model the tail from virtual
D

mesons. The combinato-
rial and continuum background yields are estimated from
data. We fit the hadronic
B
tag
m
ES
distributions for

B
!
D




events as described in [
7
], and we obtain the
number of background events from the integral of the
background function in the
m
ES
signal region.
Table
II
summarizes the results from two fits: one in
which we fit the charged and neutral
B
samples separately,
and one in which we impose the isospin constraints
B
ð
B

!
D




Þ
=
B
ð

B
0
!
D




Þ¼

B

=

B
0
. The
latter fit yields a significance greater than 5 standard devi-
ations for all four
D

states including systematic uncer-
tainties. The results of this fit are shown in Fig.
1
.
The
D

2
contributes to both the
D
and the
D


samples. In the nominal fit, we fix the ratio
B
ð
D

2
!
D
Þ
=
B
ð
D

2
!
D


Þ
to 2.2 [
5
]. When we allow this ratio
to float, we obtain
1
:
9

0
:
6
.
To reduce systematic uncertainties, we measure the
ratios of the
B
ð

B
!
D




Þ
branching fractions to the
inclusive

B
0
and
B

semileptonic branching fractions. A
sample of

B
!
X‘



events is selected by identifying a
charged lepton with
p

>
0
:
6 GeV
=c
and the correct
charge correlation with the
B
tag
candidate. In the case of
multiple
B
tag
candidates in an event, we select the one
reconstructed in the decay channel with the highest purity,
defined as the fraction of signal events in the
m
ES
signal
region. Background components that peak in the
m
ES
signal region include cascade
B
meson decays (i.e., the
TABLE I.
m
2
miss
selection criteria.
Mode
Selection Criteria
B

!
D






0
:
25
<m
2
miss
<
0
:
25 GeV
2
=c
4
B

!
D
þ






0
:
25
<m
2
miss
<
0
:
8 GeV
2
=c
4

B
0
!
D

0

þ




0
:
2
<m
2
miss
<
0
:
35 GeV
2
=c
4

B
0
!
D
0

þ




0
:
15
<m
2
miss
<
0
:
85 GeV
2
=c
4
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-5
lepton does not come directly from the
B
) and hadronic
decays, and are subtracted using the corresponding MC
predictions.
The total yield for the inclusive

B
!
X‘



decays is
obtained from a maximum likelihood fit to the
m
ES
distri-
bution of the
B
tag
candidates, as described in [
7
]. The fit
yields
198 897

1578
events for the
B

!
X‘



sample
and
120 168

1036
events for the

B
0
!
X‘



sample.
The ratios
B
ð

B
!
D




Þ
=
B
ð

B
!
X‘



Þ¼
ð
N
sig
=
sig
Þð
sl
=N
sl
Þ
are obtained by correcting the signal
yields for the reconstruction efficiencies (estimated from
B

B
MC events). Here,
N
sig
is the number of

B
!
D




signal events, reported in Table
II
together with the corre-
sponding reconstruction efficiencies
sig
,
N
sl
is the

B
!
X‘



signal yield, and
sl
is the corresponding recon-
struction efficiency including the
B
tag
reconstruction, equal
to 0.39% and 0.25% for the
B

!
X‘



and

B
0
!
X‘



decays, respectively. The absolute branching frac-
tions
B
ð

B
!
D




Þ
are then determined using the
semileptonic branching fraction
B
ð

B
!
X‘



Þ¼
ð
10
:
78

0
:
18
Þ
%
and the ratio of the

B
0
and the
B

life-
times

B

=

B
0
¼
1
:
071

0
:
009
[
5
].
Numerous sources of systematic uncertainties have been
investigated. The largest uncertainty is due to the determi-
nation of the

B
!
D




signal yields (resulting in 5.5–
17.0% relative systematic uncertainty depending on the
D

state). This uncertainty is estimated using ensembles
of fits to the data in which the input parameters are varied
within the known uncertainties in the PDF parameteriza-
tion (0.2–8.7%), the shape and yield of the combinatorial
and continuum background (0.2–10.4%), the modeling of
the broad
D

states (4.5–13.8%), and the
D

feed-down
rate (0.5–4.0%). We check that the combinatorial and con-
tinuum background shape is well reproduced by the simu-
lation by verifying that the MC samples of right-sign and
wrong-sign
D
ðÞ

combinations have similar shapes, and
that the wrong-sign distribution in the data agrees well with
that in the simulation. We observe an excess of events in
the low invariant mass difference region in the four
samples that is not accounted for by the background
PDF. We study

B
!
D
ðÞ
n‘



(
n>
1
) decays, that are
not included in our standard MC simulation, as a possible
source of this excess. We use different MC models for
these decays, and, assuming
B
ð

B
!
D
ðÞ
n‘



Þ¼ð
1

1
Þ
%
, we find that they account for about 30% of the
observed excess. We determine the systematic uncertainty
(0.1–3.2%), included in the yield uncertainty, by repeating
the fit using the different models and varying this back-
ground yield within the assumed branching fraction error.
The uncertainties due to the detector simulation are deter-
mined by varying, within bounds given by data control
samples, the charged track reconstruction efficiency (1.3–
2.0%), the photon reconstruction efficiency (0.2–4.8%), the
lepton identification efficiency (1.2–1.6%), and the recon-
struction efficiency for low momentum charged (1.2%) and
neutral pions (1.3%). We use an HQET model [
8
] to test
the model dependence of the

B
!
D




simulation
(0.8–2.5%). We include the uncertainty on the branching
fractions of the reconstructed
D
and
D

modes (3.0–4.5%),
and on the absolute branching fraction
B
ð

B
!
X‘



Þ
used for the normalization (1.9%). We also include a
systematic uncertainty due to differences in the efficiency
of the
B
tag
selection in the exclusive selection of

B
!
D




decays and the inclusive

B
!
X‘



reconstruc-
tion (4.0–5.6%).
In conclusion, we report the simultaneous observation of

B
!
D




decays into the four
D

states predicted by
HQS. The measured branching fractions are reported in
Table
II
. We find results consistent with Ref. [
7
] for the
sum of the different
D

branching fractions. The rate for
TABLE II. Results from the fits to data: the

B
!
D




signal yield, the corresponding reconstruction efficiency, the product of
branching fractions, where the first error is statistical and the second systematic. For the

B
!
D

2



decay, we report yields and
product of branching fractions for the
D

2
!
D
decay mode. For the isospin-constrained results (last two columns), the
B

branching
fraction products are reported. The statistical significances,
S
stat
, are obtained by computing the difference in the log likelihood
between the nominal fit and the fit in which we fix the different signal components to 0. The significances including the systematic
uncertainty,
S
tot
, are obtained by rescaling the statistical significances by

stat
=
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

2
stat
þ

2
syst
q
.
Decay Mode
Yield
sig
ð
10

4
Þ
B
ð

B
!
D




Þ
B
ð
D

!
D
ðÞ


Þ
%
S
tot
ð
S
stat
Þ
B
%
S
tot
ð
S
sitat
Þ
B

!
D
0
1



165

18
1.24
0
:
29

0
:
03

0
:
03
9.9 (12.7)
0
:
29

0
:
03

0
:
03
10.7 (15.2)
B

!
D

0
2



97

16
1.44
0
:
15

0
:
02

0
:
02
5.2 (7.3)
0
:
12

0
:
02

0
:
02
5.3 (7.4)
B

!
D
0
0
1



142

21
1.13
0
:
27

0
:
04

0
:
05
5.4 (8.0)
0
:
30

0
:
03

0
:
04
6.4 (10.0)
B

!
D

0
0



137

26
1.15
0
:
26

0
:
05

0
:
04
4.5 (5.8)
0
:
32

0
:
04

0
:
04
6.1 (8.3)

B
0
!
D
þ
1



88

14
0.70
0
:
27

0
:
04

0
:
03
7.0 (8.4)

B
0
!
D
2



29

13
0.91
0
:
07

0
:
03

0
:
02
(
<
0
:
12@90%CL
) 2.0 (2.5)

B
0
!
D
1



86

18
0.60
0
:
31

0
:
07

0
:
05
4.6 (5.8)

B
0
!
D
0



142

26
0.70
0
:
44

0
:
08

0
:
06
4.7 (6.0)
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-6
the
D

narrow states is in good agreement with recent
measurements [
19
]; the one for the broad states is in
agreement with DELPHI [
11
] but does not agree with the
D
0
1
limit of Belle [
10
]. The rate for the broad states is found
to be large. If these broad states are indeed due to

B
!
D
0
1



and

B
!
D

0



decays, this is in conflict with
the expectations from QCD sum rules.
We are grateful for the excellent luminosity and machine
conditions provided by our PEP-II colleagues, and for the
substantial dedicated effort from the computing organiza-
tions that support
BABAR
. The collaborating institutions
wish to thank SLAC for its support and kind hospitality.
This work is supported by DOE and NSF (USA), NSERC
(Canada), CEA and CNRS-IN2P3 (France), BMBF and
DFG (Germany), INFN (Italy), FOM (The Netherlands),
NFR (Norway), MIST (Russia), MEC (Spain), and STFC
(United Kingdom). Individuals have received support from
the Marie Curie EIF (European Union) and the A. P. Sloan
Foundation.
*
Deceased
Now at Temple University, Philadelphia, PA 19122, USA
Now at Tel Aviv University, Tel Aviv, 69978, Israel
x
Also with Universita
`
di Perugia, Dipartimento di Fisica,
Perugia, Italy
k
Also with Universita
`
di Roma La Sapienza, I-00185
Roma, Italy
{
Now at University of South Alabama, Mobile, AL 36688,
USA
**
Also with Universita
`
di Sassari, Sassari, Italy
[1] M. Kobayashi and T. Maskawa, Prog. Theor. Phys.
49
, 652
(1973).
[2] The charge conjugate state is always implied unless stated
otherwise.
[3] B. Aubert
et al.
(
BABAR
Collab.), Phys. Rev. D
77
,
032002 (2008).
[4] N. Isgur and M. B. Wise, Phys. Rev. Lett.
66
, 1130 (1991).
[5] W.-M. Yao
et al.
(Particle Data Group), J. Phys. G
33
,1
(2006).
[6] B. Aubert
et al.
(
BABAR
Collab.), Phys. Rev. D
76
,
051101 (2007).
[7] B. Aubert
et al.
(
BABAR
Collab.), Phys. Rev. Lett.
100
,
151802 (2008).
[8] A. K. Leibovich, Z. Ligeti, I. W. Stewart, and M. B. Wise,
Phys. Rev. D
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501
, 86 (2001).
[10] D. Liventsev
et al.
(Belle Collab.), Phys. Rev. D
77
,
091503 (2008).
[11] J. Abdallah
et al.
(DELPHI Collab.), Eur. Phys. J. C
45
,35
(2006).
[12] B. Aubert
et al.
(
BABAR
Collab.), Nucl. Instrum. Methods
Phys. Res., Sect. A
479
, 1 (2002).
[13] S. Agostinelli
et al.
, Nucl. Instrum. Methods Phys. Res.,
Sect. A
506
, 250 (2003).
[14] D. Scora and N. Isgur, Phys. Rev. D
52
, 2783 (1995); See
also N. Isgur
et al.
,
ibid.
39
, 799 (1989).
[15] J. L. Goity and W. Roberts, Phys. Rev. D
51
, 3459 (1995).
[16] B. Aubert
et al.
(
BABAR
Collab.), Phys. Rev. Lett.
92
,
071802 (2004).
[17] B. Aubert
et al.
(
BABAR
Collab.), Phys. Rev. D
69
,
111104 (2004).
[18] K. Cranmer, Comput. Phys. Commun.
136
, 198 (2001).
[19] V. Abazov
et al.
(D0 Collab.), Phys. Rev. Lett.
95
, 171803
(2005).
]
2
) [GeV/c
(*)
)-M(D
π
(*)
M(D
0.4
0.6
0.8
1
1.2
0
5
10
15
20
25
30
35
d)
)
2
Events/(20 MeV/c
10
20
30
40
50
c)
5
10
15
20
25
30
35
40
b)
20
40
60
80
100
ν
l
1
D
ν
l
1
D’
ν
l
2
D*
ν
l
0
D*
background
a)
FIG. 1 (color online). Fit to the
m
ð
D
ðÞ

Þ
m
ð
D
ðÞ
Þ
distribu-
tion for (a)
B

!
D





, (b)
B

!
D
þ





,
(c)

B
0
!
D

0

þ



, and (d)

B
0
!
D
0

þ



: the data
(points with error bars) are compared to the results of the overall
fit (sum of the solid distributions). The PDFs for the different fit
components are stacked and shown in different colors.
PRL
101,
261802 (2008)
PHYSICAL REVIEW LETTERS
week ending
31 DECEMBER 2008
261802-7