Measurement of Semileptonic
B
Decays into Orbitally Excited Charmed Mesons
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,
5
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
A. J. Martinez,
17
T. Schalk,
17
B. A. Schumm,
17
A. Seiden,
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,
21,
†
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
A. Volk,
23
D. Bernard,
24
G. R. Bonneaud,
24
E. Latour,
24
M. Verderi,
24
P. J. Clark,
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
A. Adametz,
30
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
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
N. Arnaud,
36
J. Be
́
quilleux,
36
A. D’Orazio,
36
M. Davier,
36
J. Firmino da Costa,
36
G. Grosdidier,
36
A. Ho
̈
cker,
36
V. Lepeltier,
36
F. Le Diberder,
36
A. M. Lutz,
36
S. Pruvot,
36
P. Roudeau,
36
M. H. Schune,
36
J. Serrano,
36
V. Sordini,
36,
k
A. Stocchi,
36
G. Wormser,
36
D. J. Lange,
37
D. M. Wright,
37
I. Bingham,
38
J. P. Burke,
38
C. A. Chavez,
38
J. R. Fry,
38
E. Gabathuler,
38
R. Gamet,
38
D. E. Hutchcroft,
38
D. J. Payne,
38
C. Touramanis,
38
A. J. Bevan,
39
C. K. Clarke,
39
K. A. George,
39
F. Di Lodovico,
39
R. Sacco,
39
M. Sigamani,
39
G. Cowan,
40
H. U. Flaecher,
40
D. A. Hopkins,
40
S. Paramesvaran,
40
F. Salvatore,
40
A. C. Wren,
40
D. N. Brown,
41
C. L. Davis,
41
A. G. Denig,
42
M. Fritsch,
42
W. Gradl,
42
G. Schott,
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
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
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. LoSecco,
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
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
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
0031-9007
=
09
=
103(5)
=
051803(7)
051803-1
Ó
2009 The American Physical Society
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
(
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
Dipartmento di Fisica, 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, Canada V6T 1Z1
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 Kernund 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
Dipartimento di Fisica, 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
Dipartimento di Fisica, Universita
`
di Genova, I-16146 Genova, Italy
29
Harvard University, Cambridge, Massachusetts 02138, USA
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
051803-2
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
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
37
Lawrence Livermore National Laboratory, Livermore, California 94550, USA
38
University of Liverpool, Liverpool L69 7ZE, United Kingdom
39
Queen Mary, University of London, London, E1 4NS, United Kingdom
40
University of London, Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, United Kingdom
41
University of Louisville, Louisville, Kentucky 40292, USA
42
Johannes Gutenberg-Universita
̈
t Mainz, Institut fu
̈
r Kernphysik, D-55099 Mainz, Germany
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, Canada H3A 2T8
48a
INFN Sezione di Milano, Dipartimento di Fisica, I-20133 Milano, Italy
48b
Dipartimento di Fisica, 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, Canada H3C 3J7
51
Mount Holyoke College, South Hadley, Massachusetts 01075, USA
52a
INFN Sezione di Napoli, Dipartimento di Scienze Fisiche, I-80126 Napoli, Italy
52b
Dipartimento di Scienze Fisiche, 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
Dipartimento di Fisica, Universita
`
di Padova, I-35131 Padova, Italy
58
Laboratoire de Physique Nucle
́
aire et de Hautes Energies, IN2P3/CNRS, Universite
́
Pierre et Marie Curie-Paris6,
Universite
́
Denis Diderot-Paris7, 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
Dipartimento di Fisica, Universita
`
di Perugia, I-06100 Perugia, Italy
61a
INFN Sezione di Pisa, Dipartimento di Fisica, I-56127 Pisa, Italy
61b
Dipartimento di Fisica, Universita
`
di Pisa, I-56127 Pisa, Italy
61c
Dipartimento di Fisica, 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
Dipartimento di Fisica, 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
CEA, Irfu, SPP, Centre de Saclay, F-91191 Gif-sur-Yvette, 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
Dipartimento di Fisica Sperimentale, Universita
`
di Torino, I-10125 Torino, Italy
75a
INFN Sezione di Trieste, Dipartimento di Fisica, I-34127 Trieste, Italy
75b
Dipartimento di Fisica, Universita
`
di Trieste, I-34127 Trieste, Italy
76
IFIC, Universitat de Valencia-CSIC, E-46071 Valencia, Spain
77
University of Victoria, Victoria, British Columbia, Canada V8W 3P6
78
Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
79
University of Wisconsin, Madison, Wisconsin 53706, USA
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
051803-3
(Received 5 August 2008; published 31 July 2009)
We present a study of
B
decays into semileptonic final states containing charged and neutral
D
1
ð
2420
Þ
and
D
2
ð
2460
Þ
. The analysis is based on a data sample of
208 fb
1
collected at the
ð
4
S
Þ
resonance
with the
BABAR
detector at the PEP-II asymmetric-energy
B
factory at SLAC. With a simultaneous fit to
four different decay chains, the semileptonic branching fractions are extracted from measurements of
the mass difference
m
¼
m
ð
D
Þ
m
ð
D
Þ
distributions. Product branching fractions are determined
to be
B
ð
B
þ
!
D
0
1
‘
þ
‘
Þ
B
ð
D
0
1
!
D
þ
Þ¼ð
2
:
97
0
:
17
0
:
17
Þ
10
3
,
B
ð
B
þ
!
D
0
2
‘
þ
‘
Þ
B
ð
D
0
2
!
D
ðÞþ
Þ¼ð
2
:
29
0
:
23
0
:
21
Þ
10
3
,
B
ð
B
0
!
D
1
‘
þ
‘
Þ
B
ð
D
1
!
D
0
Þ¼ð
2
:
78
0
:
24
0
:
25
Þ
10
3
and
B
ð
B
0
!
D
2
‘
þ
‘
Þ
B
ð
D
2
!
D
ðÞ
0
Þ¼ð
1
:
77
0
:
26
0
:
11
Þ
10
3
.In
addition we measure the branching ratio
ð
D
2
!
D
Þ
=
ð
D
2
!
D
ðÞ
Þ¼
0
:
62
0
:
03
0
:
02
.
DOI:
10.1103/PhysRevLett.103.051803
PACS numbers: 13.20.He, 13.25.Ft, 14.40.Lb
Measurements of the Cabbibo-Kobayashi-Maskawa ma-
trix elements
j
V
cb
j
and
j
V
ub
j
rely on precise knowledge of
semileptonic
B
-meson decays. Decays with orbitally-
excited charm mesons (
D
) in the final state give a sig-
nificant contribution to the total semileptonic decay rate. A
better understanding of these decays will reduce the un-
certainty in the composition of the signal and backgrounds
for inclusive and exclusive measurements [
1
].
In the framework of heavy quark symmetry (HQS),
D
mesons form two doublets with
j
P
q
¼
1
=
2
and
j
P
q
¼
3
=
2
where
j
P
q
denotes the spin-parity of the light quark coupled
to the orbital angular momentum. The doublets with
j
P
q
¼
3
=
2
, namely, the
D
1
and
D
2
, have to decay via
D
wave to
conserve parity and angular momentum and therefore are
narrow with widths of order of 10 MeV [
2
]. The relative
contribution of the two doublets and the polarization of the
produced
D
mesons can be compared with QCD sum
rules [
3
] and predictions from heavy quark effective theory
[
4
].
In this Letter we describe a simultaneous measurement
of all
B
semileptonic decays to the two narrow orbitally-
excited charmed states, without explicit reconstruction of
the rest of the event. The CLEO collaboration has previ-
ously reported a branching fraction measurement for
B
þ
!
D
0
1
‘
þ
and an upper limit for
B
þ
!
D
0
2
‘
þ
[
5
].
Belle and
BABAR
have reported results using a technique
in which one of the
B
mesons in the process
ð
4
S
Þ!
B
B
is fully reconstructed [
6
].
In this analysis we use a sample with a total integrated
luminosity of
208 fb
1
, part of the complete data set
collected with the
BABAR
detector at the PEP-II storage
ring, operating at a center of mass energy of 10.58 GeV.
The
BABAR
detector [
7
] and event reconstruction [
8
] are
described in detail elsewhere. A Monte Carlo (MC) simu-
lation of the detector based on
GEANT4
[
9
] is used to
estimate signal efficiencies and to understand the back-
grounds. The sample of simulated
B
B
events is equivalent
to approximately 3 times the data sample and a dedicated
simulation of signal events based on the ISGW2 model
[
10
] has been produced with statistics equivalent to
roughly 5 times the expected signal yield contained in
the data.
D
decays are reconstructed in the decay chains
D
!
D
[
11
], and
D
!
D
. The former is accessible to
both narrow
D
states while the latter has no contribution
from the
D
1
. Intermediate
D
states are reconstructed in
D
!
D
0
and the
D
mesons are reconstructed exclu-
sively in
D
0
!
K
þ
and
D
þ
!
K
þ
þ
.
D
candi-
dates are then paired with reconstructed leptons and
required to be consistent with the semileptonic decays
B
!
D
‘
, as described in the following.
First, events which are most likely to contain a
semileptonic
B
decay are selected. We require that there
is a reconstructed
D
candidate and at least one lepton in
the event with a momentum greater than
800 MeV
=c
[
12
].
D
0
meson candidates are formed by
K
þ
combina-
tions requiring the invariant mass to be consistent with
the
D
0
mass:
1
:
846
<m
ð
K
Þ
<
1
:
877 GeV
=c
2
. This
asymmetric mass window is chosen to take into account
resolution effects of the detector. The selection is opti-
mized to maximize the significance of the selected
sample.
D
0
candidates are combined with charged and neutral
pions to form
D
candidates. For
D
0
the
0
is recon-
structed from a photon pair with an invariant mass of
115
<m
<
150 MeV
=c
2
. Those photon pairs are refit-
ted in a ‘‘mass-constrained’’ fit to match the nominal
mass of the
0
.
D
candidates are selected by their mass
difference to the
D
0
candidate:
144
<m
ð
D
0
þ
Þ
m
ð
D
0
Þ
<
148 MeV
=c
2
and
140
<m
ð
D
0
0
Þ
m
ð
D
0
Þ
<
144 MeV
=c
2
for charged and neutral
D
, respectively.
D
þ
candidates are formed from
K
þ
þ
combinations
with an invariant mass of
1
:
854
<m
ð
K
Þ
<
1
:
884 GeV
=c
2
. The
2
fit probability for the three tracks
to originate from a common vertex,
P
Vtx
, is required to be
P
Vtx
ð
K
Þ
>
0
:
01
.
Candidates for
D
and
D
are combined with charged
pions to form
D
candidates, and finally paired with
muons or electrons. The charge of the lepton is required
to match the charge of the kaon from the
D
decay.
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
051803-4
Part of the background is due to events where a
D
is
paired to a lepton from the other
B
. Thus we require that
the probability that the lepton and the pion emitted by the
D
originate from a common vertex exceeds 0.001, and
that the angle between the direction of flight of the
D
and
the lepton is more than 90 degrees.
A large fraction of the background events is due to
B
!
D
‘
decays where the
D
or its daughter
D
is paired to a
pion from the other
B
. To suppress this combinatorial
background, we make use of the variable
cos
BY
described
in the following. The energy and momentum of the
B
mesons from the
ð
4
S
Þ
decays are known from incident
beam energies. For correctly reconstructed
B
!
D
‘
decays, where the only missing particle is the neutrino,
the decay kinematics can be calculated, up to one angular
quantity, from the four-momentum of the visible decay
products (
Y
¼
D
‘
). The cosine of the angle between
the direction of flight of the
B
meson and its visible decay
product
Y
is given by
cos
BY
¼
2
E
B
E
Y
m
2
B
m
2
Y
2
j
~
p
B
jj
~
p
Y
j
;
where
E
,
j
~
p
j
and
m
are the energies, momenta, and masses
of the
B
and the
Y
, respectively. If the
Y
candidate is not
from a correctly reconstructed
B
!
D
‘
decay, the
quantity
cos
BY
no longer represents an angle, and can
take any value. We select candidates having
j
cos
BY
j
1
.
In case a
D
is reconstructed in the decay chain, a veto is
applied against decays
B
!
D
‘
by calculating the vari-
able
cos
BY
0
which is defined as above, but the
Y
system is
redefined to contain only the
D
and the lepton:
Y
0
¼
D
‘
.
Background events are rejected by the requirement
cos
BY
0
<
1
since signal events
B
!
D
‘
tend to have
values less than
1
.
To reduce combinatorial backgrounds in the decay chain
D
!
D
, only the
D
‘
candidate with
~
m
2
closest to
zero is selected, where
~
m
2
is the neutrino mass squared,
calculated in the approximation
~
p
B
¼
0
:
~
m
2
¼
m
2
B
þj
~
p
Y
j
2
2
E
B
E
Y
. Events reconstructed in the
D
!
D
0
final state are rejected if the
D
0
can be paired with
any charged pion to form a
D
þ
candidate as described
above.
In about 2% of the events more than one
D
‘
candidate
is selected and if so all of them enter the analysis.
We determine the
D
2
signal yield in the channel
D
!
D
and the
D
1
and
D
2
signal yields in the channel
D
!
D
by a binned
2
fit to the
m
¼
m
ð
D
ðÞ
Þ
m
ð
D
0
Þ
distributions. To determine the individual contributions
from
D
1
and
D
2
in the
D
final state, we make use of
the helicity angle distribution of the
D
,
#
h
, which is
defined as the angle between the two pions emitted by
the
D
and the
D
in the rest frame of the
D
.Fora
D
from a
D
2
this distribution varies as
sin
2
#
h
, whereas for
D
1
decays, the helicity angle is distributed like
1
þ
A
D
1
cos
2
#
h
, where
A
D
1
is a parameter which depends on
the initial polarization of the
D
1
and a possible
S
-wave
contribution to the
D
1
decay. To exploit this feature, we
split the data for the two decay chains involving a
D
into
four subsamples, corresponding to four equal size bins in
j
cos
#
h
j
.
The resulting ten
m
distributions are fitted simulta-
neously to determine 12 parameters describing the signal
yields and distributions, and 22 parameters to adjust the
background yields and shapes. The mass differences for the
signal events are described by Breit-Wigner functions.
There are four parameters giving the signal yields for the
semileptonic decays involving the two narrow states,
charged and neutral. The masses of the states are also
fitted, but are constrained to be equal for charged and
neutral states, giving two parameters. Four additional pa-
rameters arise from the effective widths of the
D
states,
which represent a convolution of the intrinsic widths and
detector resolution effects. The latter contributes approxi-
mately
2
–
3 MeV
=c
2
, depending on the mode. The fit also
determines the
D
2
branching ratio
B
D=D
ðÞ
¼
ð
D
2
!
D
Þ
=
ð
ð
D
2
!
D
Þþ
ð
D
2
!
D
ÞÞ
and the
D
1
po-
larization amplitude
A
D
1
.
Backgrounds are modeled by cubic functions in
m
.
The background shape in the
D
channel is found to be
the same in all helicity bins for each final state. The fit thus
has three shape parameters for each decay chain, while the
number of background events is determined independently
in each bin.
The selection efficiency is deduced from a fit to the
simulation. This fit uses the same parametrization as the
fit determining the signal yield from data and is applied to
the sum of the full background simulation and for one
signal decay chain at a time. For a given decay mode the
efficiencies are found to be the same for
D
1
and
D
2
,
specifically:
ð
D
þ
Þ¼ð
6
:
89
0
:
12
Þ
%
,
ð
D
0
Þ¼
ð
5
:
34
0
:
12
Þ
%
,
ð
D
þ
Þ¼ð
12
:
88
0
:
96
Þ
%
and
ð
D
0
Þ¼ð
17
:
56
0
:
70
Þ
%
, where the quoted uncertain-
ties are the statistical uncertainties from the fit. For the
decays including a
D
the efficiency is multiplied by the
probability for a
D
to decay with a value of
j
cos
#
h
j
falling into a given bin. This factor includes the theoretical
distribution discussed above as well as corrections for the
different detector acceptances in the four helicity bins of up
to 10%. The total number of
B
mesons in the data sample
used for the present work is
N
B
B
¼ð
236
:
0
2
:
6
Þ
10
6
[
13
]. For the charged and neutral
B
mesons we assume
ð
ð
4
S
Þ!
B
þ
B
Þ
=
ð
ð
4
S
Þ!
B
0
B
0
Þ¼
1
:
065
0
:
026
[
14
].
The fit procedure has been extensively validated. The
analysis procedure is tested on statistically independent
MC simulated data samples and was found to reproduce
the input signal parameters with a
2
=n
¼
12
:
66
=
12
,
where
n
is the number of signal parameters. Consistent
fit results were also obtained when the data sample was
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
051803-5
separated into subsamples representing specific data taking
periods, separated by lepton species or restricting it to
certain decay modes, using charged or neutral
D
only,
or combining the helicity bins. The results of the fit are
shown in Fig.
1
. As expected, the contribution of the
D
2
vanishes for large values of
j
cos
#
h
j
while the contribution
of the
D
1
is suppressed for
cos
#
h
close to zero. The
extracted yields are given in Table
I
.
Systematic uncertainties have been analyzed and their
impact on the fitted yields have been estimated taking into
account correlations between fit parameters. Efficiencies
for reconstructing and selecting the particles of the final
state are derived from Monte Carlo simulation. The simu-
lation of the tracking and the
0
reconstruction have been
studied by comparing
decays to one and three charged
tracks and with or without a neutral pion. Uncertainties
introduced by the particle identification for kaons and
leptons are studied using control samples with high purities
for the particles in question. The impact of the finite
statistics of the simulated signal events is deduced from
the fit error of the efficiency determination.
The uncertainty on the number of charged and neutral
B
mesons in the data set is determined as in [
13
,
14
] and the
branching fractions of the decays of the
D
and the
D
are
taken from [
15
].
Uncertainties introduced by the physics model which
was used to simulate the MC data have been addressed by
reweighting the signal MC calculations to an alternative
decay model based on HQET [
4
]. The fit was repeated with
efficiencies deduced from the reweighted signal MC data
and the deviations in the results are taken as systematic
uncertainties. A possible influence of the background de-
scription has been tested by varying the parametrizations.
TABLE I. Extracted yields for the four signal modes in the five
relevant
m
spectra.
Mode
j
cos
#
h
j
D
0
1
D
0
2
D
þ
1
D
þ
2
D
þ
½
0
:
00
j
0
:
25
344
273
212
152
D
þ
½
0
:
25
j
0
:
50
470
238
286
123
D
þ
½
0
:
50
j
0
:
75
699
170
439
83
D
þ
½
0
:
75
j
1
:
00
1027
67
668
31
D
þ
8414
3361
0
50
100
150
200
250
300
350
events/10 MeV/c
2
0
50
100
150
200
250
0.4
0.6
0.8
(a)
|
cos
θ
h
|<
0.25
(f)
0.4
0.6
0.8
(b)
0.25
<|
cos
θ
h
|<
0.5
(g)
0.4
0.6
0.8
(c)
0.5
<|
cos
θ
h
|<
0.75
(h)
0.4
0.6
0.8
(d)
0.75
<
|
cos
θ
h
|
(i)
∆
m (GeV/c
2
)
0
1
2
3
4
5
6
10
3
events/5 MeV/c
2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0.4
0.6
0.8
(e)
(k)
∆
m (GeV/c
2
)
FIG. 1.
m
spectra for the selected data and the results of the fitted functions. The solid line represents the complete fit function,
dotted (
D
1
) and dashed (
D
2
) lines for the signal and dash-dotted the for background. (a) to (d) show the mode
D
0
!
D
þ
with
increasing values for
j
cos
#
h
j
, (e) the mode
D
0
!
D
þ
. (f) to (i) show the corresponding bins in
j
cos
#
h
j
for the mode
D
þ
!
D
0
þ
and (k) the mode
D
þ
!
D
0
þ
.
TABLE II. Summary of systematic uncertainties of the deter-
mination of the semileptonic branching fractions.
Source
B
ð
B
!
D
‘
Þ
=
B
ð
B
!
D
‘
Þ½
%
D
0
1
D
0
2
D
þ
1
D
þ
2
Tracking
1.76
1.39
1.03
1.14
0
efficiency
0.06
0.29
3.25
0.60
Particle identification 2.61
2.75
3.11
1.60
MC statistics
1.80
5.61
2.50
3.32
Helicity correction
0.65
0.14
0.17
0.31
Number of
B
mesons 2.68
2.68
2.68
2.68
B
ð
D
þ
!
D
0
þ
Þ
0.76
0.19
0.04
0.10
B
ð
D
0
!
D
0
0
Þ
0.11
0.45
5.07
0.93
B
ð
D
0
!
K
þ
Þ
1.89
0.42
1.78
2.03
B
ð
D
þ
!
K
þ
þ
Þ
0.07
2.67
0.24
0.54
Signal modeling
2.11
4.75
3.21
1.95
bkg. parametrization 1.93
1.68
3.20
2.71
Total
5.76
9.03
9.16
6.17
PRL
103,
051803 (2009)
PHYSICAL REVIEW LETTERS
week ending
31 JULY 2009
051803-6
The backgrounds are alternatively described by a square
root function,
f
ð
m
Þ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
m
m
0
p
, where
m
0
is the kine-
matic limit, multiplied by either polynomials or exponen-
tials in
m
.
Table
II
gives a summary of the various sources of
systematic uncertainty and their impact on the results.
Added in quadrature the total systematic uncertainties in
the semileptonic branching fractions are 6%–10%, depend-
ing on the
D
type.
In summary, we have measured the four branching
fractions of
B
mesons decaying semileptonically into nar-
row
D
states. The
D
decay rates are unknown; thus, we
can only determine the product branching fractions:
B
ð
B
þ
!
D
0
1
‘
þ
‘
Þ
B
ð
D
0
1
!
D
þ
Þ¼ð
2
:
97
0
:
17
stat
0
:
17
syst
Þ
10
3
;
B
ð
B
þ
!
D
0
2
‘
þ
‘
Þ
B
ð
D
0
2
!
D
ðÞþ
Þ¼ð
2
:
29
0
:
23
stat
0
:
21
syst
Þ
10
3
;
B
ð
B
0
!
D
1
‘
þ
‘
Þ
B
ð
D
1
!
D
0
Þ¼ð
2
:
78
0
:
24
stat
0
:
25
syst
Þ
10
3
;
B
ð
B
0
!
D
2
‘
þ
‘
Þ
B
ð
D
2
!
D
ðÞ
0
Þ¼ð
1
:
77
0
:
26
stat
0
:
11
syst
Þ
10
3
:
We observe all modes with significance greater than
5
,
among them evidence of the
D
2
contribution to the decay
B
!
D
‘
. For modes already observed we find results
in agreement with previous measurements, but achieve
better precisions [
5
,
6
,
16
].
For the decays of the
D
we measure the branching ratio
B
D=D
ðÞ
¼
0
:
62
0
:
03
stat
0
:
02
syst
. This ratio is in agree-
ment with theoretical predictions [
2
] and previous mea-
surements [
15
] but has a smaller uncertainty by a factor of
about four.
For the
D
1
we determine the polarization parameter to
be
A
D
1
¼
3
:
8
0
:
6
stat
0
:
8
syst
. It is the first measurement
of the
D
1
polarization, within the uncertainties consistent
with unpolarized
D
1
decaying purely via
D
wave, which
gives the prediction
A
D
1
¼
3
, but violates HQS [
4
].
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), MES (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
†
Present address: Temple University, Philadelphia,
Pennsylvania 19122, USA.
‡
Present address: Tel Aviv University, Tel Aviv, 69978,
Israel.
x
Also at Universita
`
di Perugia, Dipartimento di Fisica,
Perugia, Italy.
k
Also at Universita
`
di Roma La Sapienza, I-00185 Roma,
Italy.
{
Present address: University of South AL, Mobile, AL
36688, USA.
**
Also at Universita
`
di Sassari, Sassari, Italy.
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