Branching fraction limits for
B
0
decays to
0
,
0
0
and
0
B. Aubert,
1
R. Barate,
1
D. Boutigny,
1
F. Couderc,
1
Y. Karyotakis,
1
J. P. Lees,
1
V. Poireau,
1
V. Tisserand,
1
A. Zghiche,
1
E. Grauges,
2
A. Palano,
3
M. Pappagallo,
3
J. C. Chen,
4
N. D. Qi,
4
G. Rong,
4
P. Wang,
4
Y. S. Zhu,
4
G. Eigen,
5
I. Ofte,
5
B. Stugu,
5
G. S. Abrams,
6
M. Battaglia,
6
D. S. Best,
6
D. N. Brown,
6
J. Button-Shafer,
6
R. N. Cahn,
6
E. Charles,
6
C. T. Day,
6
M. S. Gill,
6
A. V. Gritsan,
6,
*
Y. Groysman,
6
R. G. Jacobsen,
6
J. A. Kadyk,
6
L. T. Kerth,
6
Yu. G. Kolomensky,
6
G. Kukartsev,
6
G. Lynch,
6
L. M. Mir,
6
P. J. Oddone,
6
T. J. Orimoto,
6
M. Pripstein,
6
N. A. Roe,
6
M. T. Ronan,
6
W. A. Wenzel,
6
M. Barrett,
7
K. E. Ford,
7
T. J. Harrison,
7
A. J. Hart,
7
C. M. Hawkes,
7
S. E. Morgan,
7
A. T. Watson,
7
M. Fritsch,
8
K. Goetzen,
8
T. Held,
8
H. Koch,
8
B. Lewandowski,
8
M. Pelizaeus,
8
K. Peters,
8
T. Schroeder,
8
M. Steinke,
8
J. T. Boyd,
9
J. P. Burke,
9
W. N. Cottingham,
9
D. Walker,
9
T. Cuhadar-Donszelmann,
10
B. G. Fulsom,
10
C. Hearty,
10
N. S. Knecht,
10
T. S. Mattison,
10
J. A. McKenna,
10
A. Khan,
11
P. Kyberd,
11
M. Saleem,
11
L. Teodorescu,
11
V. E. Blinov,
12
A. D. Bukin,
12
A. Buzykaev,
12
V. P. Druzhinin,
12
V. B. Golubev,
12
A. P. Onuchin,
12
S. I. Serednyakov,
12
Yu. I. Skovpen,
12
E. P. Solodov,
12
K. Yu Todyshev,
12
M. Bondioli,
13
M. Bruinsma,
13
M. Chao,
13
S. Curry,
13
I. Eschrich,
13
D. Kirkby,
13
A. J. Lankford,
13
P. Lund,
13
M. Mandelkern,
13
R. K. Mommsen,
13
W. Roethel,
13
D. P. Stoker,
13
S. Abachi,
14
C. Buchanan,
14
S. D. Foulkes,
15
J. W. Gary,
15
O. Long,
15
B. C. Shen,
15
K. Wang,
15
L. Zhang,
15
D. del Re,
16
H. K. Hadavand,
16
E. J. Hill,
16
H. P. Paar,
16
S. Rahatlou,
16
V. Sharma,
16
J. W. Berryhill,
17
C. Campagnari,
17
A. Cunha,
17
B. Dahmes,
17
T. M. Hong,
17
J. D. Richman,
17
T. W. Beck,
18
A. M. Eisner,
18
C. J. Flacco,
18
C. A. Heusch,
18
J. Kroseberg,
18
W. S. Lockman,
18
G. Nesom,
18
T. Schalk,
18
B. A. Schumm,
18
A. Seiden,
18
P. Spradlin,
18
D. C. Williams,
18
M. G. Wilson,
18
J. Albert,
19
E. Chen,
19
G. P. Dubois-Felsmann,
19
A. Dvoretskii,
19
D. G. Hitlin,
19
I. Narsky,
19
T. Piatenko,
19
F. C. Porter,
19
A. Ryd,
19
A. Samuel,
19
R. Andreassen,
20
G. Mancinelli,
20
B. T. Meadows,
20
M. D. Sokoloff,
20
E. A. Antillon,
21
F. Blanc,
21
P. C. Bloom,
21
S. Chen,
21
W. T. Ford,
21
J. F. Hirschauer,
21
A. Kreisel,
21
U. Nauenberg,
21
A. Olivas,
21
W. O. Ruddick,
21
J. G. Smith,
21
K. A. Ulmer,
21
S. R. Wagner,
21
J. Zhang,
21
A. Chen,
22
E. A. Eckhart,
22
A. Soffer,
22
W. H. Toki,
22
R. J. Wilson,
22
F. Winklmeier,
22
Q. Zeng,
22
D. D. Altenburg,
23
E. Feltresi,
23
A. Hauke,
23
H. Jasper,
23
B. Spaan,
23
T. Brandt,
24
V. Klose,
24
H. M. Lacker,
24
R. Nogowski,
24
A. Petzold,
24
J. Schubert,
24
K. R. Schubert,
24
R. Schwierz,
24
J. E. Sundermann,
24
A. Volk,
24
D. Bernard,
25
G. R. Bonneaud,
25
P. Grenier,
25,†
E. Latour,
25
Ch. Thiebaux,
25
M. Verderi,
25
D. J. Bard,
26
P. J. Clark,
26
W. Gradl,
26
F. Muheim,
26
S. Playfer,
26
Y. Xie,
26
M. Andreotti,
27
D. Bettoni,
27
C. Bozzi,
27
R. Calabrese,
27
G. Cibinetto,
27
E. Luppi,
27
M. Negrini,
27
L. Piemontese,
27
F. Anulli,
28
R. Baldini-Ferroli,
28
A. Calcaterra,
28
R. de Sangro,
28
G. Finocchiaro,
28
S. Pacetti,
28
P. Patteri,
28
I. M. Peruzzi,
28,‡
M. Piccolo,
28
A. Zallo,
28
A. Buzzo,
29
R. Capra,
29
R. Contri,
29
M. Lo Vetere,
29
M. M. Macri,
29
M. R. Monge,
29
S. Passaggio,
29
C. Patrignani,
29
E. Robutti,
29
A. Santroni,
29
S. Tosi,
29
G. Brandenburg,
30
K. S. Chaisanguanthum,
30
M. Morii,
30
J. Wu,
30
R. S. Dubitzky,
31
J. Marks,
31
S. Schenk,
31
U. Uwer,
31
W. Bhimji,
32
D. A. Bowerman,
32
P. D. Dauncey,
32
U. Egede,
32
R. L. Flack,
32
J. R. Gaillard,
32
J. A. Nash,
32
M. B. Nikolich,
32
W. Panduro Vazquez,
32
X. Chai,
33
M. J. Charles,
33
W. F. Mader,
33
U. Mallik,
33
V. Ziegler,
33
J. Cochran,
34
H. B. Crawley,
34
L. Dong,
34
V. Eyges,
34
W. T. Meyer,
34
S. Prell,
34
E. I. Rosenberg,
34
A. E. Rubin,
34
G. Schott,
35
N. Arnaud,
36
M. Davier,
36
G. Grosdidier,
36
A. Ho
̈
cker,
36
F. Le Diberder,
36
V. Lepeltier,
36
A. M. Lutz,
36
A. Oyanguren,
36
T. C. Petersen,
36
S. Pruvot,
36
S. Rodier,
36
P. Roudeau,
36
M. H. Schune,
36
A. Stocchi,
36
W. F. Wang,
36
G. Wormser,
36
C. H. Cheng,
37
D. J. Lange,
37
D. M. Wright,
37
C. A. Chavez,
38
I. J. Forster,
38
J. R. Fry,
38
E. Gabathuler,
38
R. Gamet,
38
K. A. George,
38
D. E. Hutchcroft,
38
D. J. Payne,
38
K. C. Schofield,
38
C. Touramanis,
38
A. J. Bevan,
39
F. Di Lodovico,
39
W. Menges,
39
R. Sacco,
39
C. L. Brown,
40
G. Cowan,
40
H. U. Flaecher,
40
D. A. Hopkins,
40
P. S. Jackson,
40
T. R. McMahon,
40
S. Ricciardi,
40
F. Salvatore,
40
D. N. Brown,
41
C. L. Davis,
41
J. Allison,
42
N. R. Barlow,
42
R. J. Barlow,
42
Y. M. Chia,
42
C. L. Edgar,
42
M. P. Kelly,
42
G. D. Lafferty,
42
M. T. Naisbit,
42
J. C. Williams,
42
J. I. Yi,
42
C. Chen,
43
W. D. Hulsbergen,
43
A. Jawahery,
43
D. Kovalskyi,
43
C. K. Lae,
43
D. A. Roberts,
43
G. Simi,
43
G. Blaylock,
44
C. Dallapiccola,
44
S. S. Hertzbach,
44
X. Li,
44
T. B. Moore,
44
S. Saremi,
44
H. Staengle,
44
S. Y. Willocq,
44
R. Cowan,
45
K. Koeneke,
45
G. Sciolla,
45
S. J. Sekula,
45
M. Spitznagel,
45
F. Taylor,
45
R. K. Yamamoto,
45
H. Kim,
46
P. M. Patel,
46
C. T. Potter,
46
S. H. Robertson,
46
A. Lazzaro,
47
V. Lombardo,
47
F. Palombo,
47
J. M. Bauer,
48
L. Cremaldi,
48
V. Eschenburg,
48
R. Godang,
48
R. Kroeger,
48
J. Reidy,
48
D. A. Sanders,
48
D. J. Summers,
48
H. W. Zhao,
48
S. Brunet,
49
D. Co
ˆ
te
́
,
49
M. Simard,
49
P. Taras,
49
F. B. Viaud,
49
H. Nicholson,
50
N. Cavallo,
51,
x
G. De Nardo,
51
F. Fabozzi,
51,
x
C. Gatto,
51
L. Lista,
51
D. Monorchio,
51
D. Piccolo,
51
C. Sciacca,
51
M. Baak,
52
H. Bulten,
52
G. Raven,
52
H. L. Snoek,
52
C. P. Jessop,
53
J. M. LoSecco,
53
T. Allmendinger,
54
G. Benelli,
54
K. K. Gan,
54
K. Honscheid,
54
D. Hufnagel,
54
P. D. Jackson,
54
H. Kagan,
54
R. Kass,
54
T. Pulliam,
54
A. M. Rahimi,
54
R. Ter-Antonyan,
54
Q. K. Wong,
54
N. L. Blount,
55
J. Brau,
55
R. Frey,
55
O. Igonkina,
55
M. Lu,
55
R. Rahmat,
55
N. B. Sinev,
55
D. Strom,
55
J. Strube,
55
E. Torrence,
55
F. Galeazzi,
56
A. Gaz,
56
M. Margoni,
56
M. Morandin,
56
A. Pompili,
56
M. Posocco,
56
M. Rotondo,
56
PHYSICAL REVIEW D
73,
071102(R) (2006)
RAPID COMMUNICATIONS
1550-7998
=
2006
=
73(7)
=
071102(8)$23.00
071102-1
©
2006 The American Physical Society
F. Simonetto,
56
R. Stroili,
56
C. Voci,
56
M. Benayoun,
57
J. Chauveau,
57
P. David,
57
L. Del Buono,
57
Ch. de la Vaissie
`
re,
57
O. Hamon,
57
B. L. Hartfiel,
57
M. J. J. John,
57
Ph. Leruste,
57
J. Malcle
`
s,
57
J. Ocariz,
57
L. Roos,
57
G. Therin,
57
P. K. Behera,
58
L. Gladney,
58
J. Panetta,
58
M. Biasini,
59
R. Covarelli,
59
M. Pioppi,
59
C. Angelini,
60
G. Batignani,
60
S. Bettarini,
60
F. Bucci,
60
G. Calderini,
60
M. Carpinelli,
60
R. Cenci,
60
F. Forti,
60
M. A. Giorgi,
60
A. Lusiani,
60
G. Marchiori,
60
M. A. Mazur,
60
M. Morganti,
60
N. Neri,
60
E. Paoloni,
60
M. Rama,
60
G. Rizzo,
60
J. Walsh,
60
M. Haire,
61
D. Judd,
61
D. E. Wagoner,
61
J. Biesiada,
62
N. Danielson,
62
P. Elmer,
62
Y. P. Lau,
62
C. Lu,
62
J. Olsen,
62
A. J. S. Smith,
62
A. V. Telnov,
62
F. Bellini,
63
G. Cavoto,
63
A. D’Orazio,
63
E. Di Marco,
63
R. Faccini,
63
F. Ferrarotto,
63
F. Ferroni,
63
M. Gaspero,
63
L. Li Gioi,
63
M. A. Mazzoni,
63
S. Morganti,
63
G. Piredda,
63
F. Polci,
63
F. Safai Tehrani,
63
C. Voena,
63
H. Schro
̈
der,
64
R. Waldi,
64
T. Adye,
65
N. De Groot,
65
B. Franek,
65
E. O. Olaiya,
65
F. F. Wilson,
65
S. Emery,
66
A. Gaidot,
66
S. F. Ganzhur,
66
G. Hamel de Monchenault,
66
W. Kozanecki,
66
M. Legendre,
66
B. Mayer,
66
G. Vasseur,
66
Ch. Ye
`
che,
66
M. Zito,
66
W. Park,
67
M. V. Purohit,
67
A. W. Weidemann,
67
J. R. Wilson,
67
M. T. Allen,
68
D. Aston,
68
R. Bartoldus,
68
P. Bechtle,
68
N. Berger,
68
A. M. Boyarski,
68
R. Claus,
68
J. P. Coleman,
68
M. R. Convery,
68
M. Cristinziani,
68
J. C. Dingfelder,
68
D. Dong,
68
J. Dorfan,
68
D. Dujmic,
68
W. Dunwoodie,
68
R. C. Field,
68
T. Glanzman,
68
S. J. Gowdy,
68
V. Halyo,
68
C. Hast,
68
T. Hryn’ova,
68
W. R. Innes,
68
M. H. Kelsey,
68
P. Kim,
68
M. L. Kocian,
68
D. W. G. S. Leith,
68
J. Libby,
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
C. P. O’Grady,
68
V. E. Ozcan,
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
J. Stelzer,
68
D. Su,
68
M. K. Sullivan,
68
K. Suzuki,
68
S. K. Swain,
68
J. M. Thompson,
68
J. Va’vra,
68
N. van Bakel,
68
M. Weaver,
68
A. J. R. Weinstein,
68
W. J. Wisniewski,
68
M. Wittgen,
68
D. H. Wright,
68
A. K. Yarritu,
68
K. Yi,
68
C. C. Young,
68
P. R. Burchat,
69
A. J. Edwards,
69
S. A. Majewski,
69
B. A. Petersen,
69
C. Roat,
69
L. Wilden,
69
S. Ahmed,
70
M. S. Alam,
70
R. Bula,
70
J. A. Ernst,
70
V. Jain,
70
B. Pan,
70
M. A. Saeed,
70
F. R. Wappler,
70
S. B. Zain,
70
W. Bugg,
71
M. Krishnamurthy,
71
S. M. Spanier,
71
R. Eckmann,
72
J. L. Ritchie,
72
A. Satpathy,
72
R. F. Schwitters,
72
J. M. Izen,
73
I. Kitayama,
73
X. C. Lou,
73
S. Ye,
73
F. Bianchi,
74
M. Bona,
74
F. Gallo,
74
D. Gamba,
74
M. Bomben,
75
L. Bosisio,
75
C. Cartaro,
75
F. Cossutti,
75
G. Della Ricca,
75
S. Dittongo,
75
S. Grancagnolo,
75
L. Lanceri,
75
L. Vitale,
75
V. Azzolini,
76
F. Martinez-Vidal,
76
R. S. Panvini,
77,
k
Sw. Banerjee,
78
B. Bhuyan,
78
C. M. Brown,
78
D. Fortin,
78
K. Hamano,
78
R. Kowalewski,
78
I. M. Nugent,
78
J. M. Roney,
78
R. J. Sobie,
78
J. J. Back,
79
P. F. Harrison,
79
T. E. Latham,
79
G. B. Mohanty,
79
H. R. Band,
80
X. Chen,
80
B. Cheng,
80
S. Dasu,
80
M. Datta,
80
A. M. Eichenbaum,
80
K. T. Flood,
80
M. T. Graham,
80
J. J. Hollar,
80
J. R. Johnson,
80
P. E. Kutter,
80
H. Li,
80
R. Liu,
80
B. Mellado,
80
A. Mihalyi,
80
A. K. Mohapatra,
80
Y. Pan,
80
M. Pierini,
80
R. Prepost,
80
P. Tan,
80
S. L. Wu,
80
Z. Yu,
80
and H. Neal
81
(
B
A
B
AR
Collaboration)
1
Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France
2
Universitat de Barcelona, Fac. Fisica Dept. ECM, Avda Diagonal 647, 6a planta, E-08028 Barcelona, Spain
3
Dipartimento di Fisica and INFN, Universita
`
di Bari, I-70126 Bari, Italy
4
Institute of High Energy Physics, Beijing 100039, China
5
University of Bergen, Institute of Physics, N-5007 Bergen, Norway
6
Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720, USA
7
University of Birmingham, Birmingham, B15 2TT, United Kingdom
8
Ruhr Universita
̈
t Bochum, Institut fu
̈
r Experimentalphysik 1, D-44780 Bochum, Germany
9
University of Bristol, Bristol BS8 1TL, United Kingdom
10
University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
11
Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom
12
Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia
13
University of California at Irvine, Irvine, California 92697, USA
14
University of California at Los Angeles, Los Angeles, California 90024, USA
15
University of California at Riverside, Riverside, California 92521, USA
16
University of California at San Diego, La Jolla, California 92093, USA
17
University of California at Santa Barbara, Santa Barbara, California 93106, USA
18
University of California at Santa Cruz, Institute for Particle Physics, Santa Cruz, California 95064, USA
19
California Institute of Technology, Pasadena, California 91125, USA
20
University of Cincinnati, Cincinnati, Ohio 45221, USA
21
University of Colorado, Boulder, Colorado 80309, USA
22
Colorado State University, Fort Collins, Colorado 80523, USA
23
Universita
̈
t Dortmund, Institut fu
̈
r Physik, D-44221 Dortmund, Germany
24
Technische Universita
̈
t Dresden, Institut fu
̈
r Kern- und Teilchenphysik, D-01062 Dresden, Germany
B. AUBERT
et al.
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-2
25
Ecole Polytechnique, LLR, F-91128 Palaiseau, France
26
University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
27
Universita
`
di Ferrara, Dipartimento di Fisica and INFN, I-44100 Ferrara, Italy
28
Laboratori Nazionali di Frascati dell’INFN, I-00044 Frascati, Italy
29
Universita
`
di Genova, Dipartimento di Fisica and INFN, I-16146 Genova, Italy
30
Harvard University, Cambridge, Massachusetts 02138, USA
31
Universita
̈
t Heidelberg, Physikalisches Institut, Philosophenweg 12, D-69120 Heidelberg, 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
Universita
̈
t Karlsruhe, Institut fu
̈
r Experimentelle Kernphysik, D-76021 Karlsruhe, Germany
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, 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
University of Manchester, Manchester M13 9PL, United Kingdom
43
University of Maryland, College Park, Maryland 20742, USA
44
University of Massachusetts, Amherst, Massachusetts 01003, USA
45
Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, Massachusetts 02139, USA
46
McGill University, Montre
́
al, Que
́
bec, Canada H3A 2T8
47
Universita
`
di Milano, Dipartimento di Fisica and INFN, I-20133 Milano, Italy
48
University of Mississippi, University, Mississippi 38677, USA
49
Universite
́
de Montre
́
al, Physique des Particules, Montre
́
al, Que
́
bec, Canada H3C 3J7
50
Mount Holyoke College, South Hadley, Massachusetts 01075, USA
51
Universita
`
di Napoli Federico II, Dipartimento di Scienze Fisiche and INFN, I-80126, Napoli, Italy
52
NIKHEF, National Institute for Nuclear Physics and High Energy Physics, NL-1009 DB Amsterdam, The Netherlands
53
University of Notre Dame, Notre Dame, Indiana 46556, USA
54
Ohio State University, Columbus, Ohio 43210, USA
55
University of Oregon, Eugene, Oregon 97403, USA
56
Universita
`
di Padova, Dipartimento di Fisica and INFN, I-35131 Padova, Italy
57
Universite
́
s Paris VI et VII, Laboratoire de Physique Nucle
́
aire et de Hautes Energies, F-75252 Paris, France
58
University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
59
Universita
`
di Perugia, Dipartimento di Fisica and INFN, I-06100 Perugia, Italy
60
Universita
`
di Pisa, Dipartimento di Fisica, Scuola Normale Superiore and INFN, I-56127 Pisa, Italy
61
Prairie View A&M University, Prairie View, Texas 77446, USA
62
Princeton University, Princeton, New Jersey 08544, USA
63
Universita
`
di Roma La Sapienza, Dipartimento di Fisica and INFN, 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/Dapnia, CEA/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
74
Universita
`
di Torino, Dipartimento di Fisica Sperimentale and INFN, I-10125 Torino, Italy
75
Universita
`
di Trieste, Dipartimento di Fisica and INFN, I-34127 Trieste, Italy
76
IFIC, Universitat de Valencia-CSIC, E-46071 Valencia, Spain
77
Vanderbilt University, Nashville, Tennessee 37235, USA
*
Also with the Johns Hopkins University, Baltimore, MD 21218, USA
x
Also with Universita
`
della Basilicata, Potenza, Italy
†
Also at Laboratoire de Physique Corpusculaire, Clermont-Ferrand, France
k
Deceased
‡
Also with Universita
`
di Perugia, Dipartimento di Fisica, Perugia, Italy
BRANCHING FRACTION LIMITS FOR
B
0
DECAYS TO
0
,
0
0
and
0
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-3
78
University of Victoria, Victoria, British Columbia, Canada V8W 3P6
79
Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
80
University of Wisconsin, Madison, Wisconsin 53706, USA
81
Yale University, New Haven, Connecticut 06511, USA
(Received 7 March 2006; published 12 April 2006)
We describe searches for decays to two-body charmless final states
0
,
0
0
and
0
of
B
0
mesons
produced in
e
e
annihilation. The data, collected with the
BABAR
detector at the Stanford Linear
Accelerator Center, represent
232
10
6
produced
B
B
pairs. The results for branching fractions are, in
units of
10
6
(upper limits at 90% C.L.):
B
B
0
!
0
0
:
2
0
:
7
0
:
5
0
:
4
<
1
:
7
,
B
B
0
!
0
0
:
6
0
:
5
0
:
4
0
:
1
<
1
:
3
, and
B
B
0
!
0
0
0
:
8
0
:
8
0
:
6
0
:
1
<
2
:
1
. The first error quoted is statistical and
the second systematic.
DOI:
10.1103/PhysRevD.73.071102
PACS numbers: 13.25.Hw, 11.30.Er, 12.15.Hh
We present the results of searches for neutral
B
meson
decays to
0
,
0
and
0
0
, with a data sample ex-
panded by about a factor of 2.6 over the one used for our
previous measurements [1,2]. In the standard model (SM)
the processes that contribute to these decays are described
by color-suppressed tree and one-loop gluonic, electro-
weak or flavor-singlet penguin amplitudes. For
B
0
!
0
0
and
B
0
!
0
the color-suppressed tree diagram is
also suppressed by approximate cancellation between the
amplitudes for the
0
and for the isoscalar meson to
contain the spectator quark, resulting from the mesons’
isospin couplings to the quarks. Estimates of the branching
fractions for these modes have been obtained from calcu-
lations based on QCD factorization [3,4], perturbative
QCD (for
B
0
!
0
0
) [5], soft collinear effective theory
[6], and flavor-SU(3) symmetry [7,8]. The expectations lie
in the approximate ranges
0
:
2
–
1
:
0
10
6
for
B
0
!
0
0
, and
0
:
3
–
2
10
6
for
B
0
!
0
.
These decays are also of interest in constraining the
expected value of the time-dependent
CP
-violation asym-
metry parameter
S
f
in the decay with
f
0
K
0
S
[7,9,10].
The leading-order SM calculation gives the equality
S
0
K
0
S
S
J= K
0
S
, where the latter has been precisely mea-
sured [11], and equals
sin2
in the SM. The
CP
asymme-
try in the charmless modes is sensitive to contributions
from new physics, but also to contamination from sublead-
ing SM amplitudes. The most stringent constraint on such
contamination in
S
0
K
0
S
comes from the measured branch-
ing fractions of the three decay modes studied in this paper
[7,9,10]. Recently it has also been suggested [12,13] that
B
0
!
0
0
and
B
0
!
0
can be used to constrain the
contribution from isospin-breaking effects on the value of
sin2
in
B
0
!
decays.
The results presented here are based on data collected
with the
BABAR
detector [14] at the PEP-II asymmetric
e
e
collider [15] located at the Stanford Linear
Accelerator
Center.
An
integrated
luminosity
of
211 fb
1
, corresponding to
232
10
6
B
B
pairs, was re-
corded at the
4
S
resonance (center-of-mass energy
s
p
10
:
58 GeV
).
Charged particles from the
e
e
interactions are de-
tected, and their momenta measured, by a combination of
five layers of double-sided silicon microstrip detectors and
a 40-layer drift chamber, both operating in the 1.5 T mag-
netic field of a superconducting solenoid. Photons and
electrons are identified with a CsI(Tl) electromagnetic
calorimeter (EMC). Further charged particle identification
(PID) is provided by the average energy loss (
dE=dx
)in
the tracking devices and by an internally reflecting ring
imaging Cherenkov detector (DIRC) covering the central
region.
We establish the event selection criteria with the aid of a
detailed Monte Carlo (MC) simulation of the
B
production
and decay sequences, and of the detector response [16].
These criteria are designed to retain signal events with high
efficiency. Applied to the data, they result in a sample
much larger than the expected signal, but with well-
characterized backgrounds. We extract the signal yields
from this sample with a maximum likelihood (ML) fit.
The
B
-daughter candidates are reconstructed through
their decays
0
!
,
!
(
),
!
0
(
3
),
0
!
(
0
), and additionally for
0
modes,
0
!
0
(
0
), where
0
!
. Table I lists
the requirements on the invariant mass of these particles’
final states. Secondary charged pions in
0
and
candi-
dates are rejected if classified as protons, kaons, or elec-
trons by their DIRC,
dE=dx
, and EMC PID signatures.
We reconstruct the
B
-meson candidate by combining the
four-momenta of a pair of daughter mesons, with a vertex
TABLE I. Selection requirements on the invariant masses of
resonances and the laboratory energies of photons from their
decay.
State
Invariant mass (MeV)
E
(MeV)
0
120
<m
<
150
>
50
490
<m
<
600
>
100
3
520
<m
0
<
570
>
30
0
910
<m
<
1000
>
100
0
910
<m
<
1000
>
200
0
510
<m
<
1000
-
B. AUBERT
et al.
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-4
constraint if the ultimate final state includes at least two
charged particles. Since the natural widths of the
,
0
, and
0
are much smaller than the resolution, we also constrain
their masses to nominal values [17] in the fit of the
B
candidate. From the kinematics of
4
S
decay we deter-
mine the energy-substituted mass
m
ES
1
4
s
p
2
B
1
=
2
and
energy difference
E
E
B
1
2
s
p
, where
E
B
;
p
B
is the
B
-meson 4-momentum vector, and all values are expressed
in the
4
S
frame. The resolution in
m
ES
is 3.0 MeV and
in
E
is 24 –50 MeV, depending on the decay mode. We
require
5
:
25 GeV
<m
ES
<
5
:
29 GeV
and
j
E
j
<
0
:
3 GeV
(
<
0
:
2 GeV
for
0
).
Backgrounds arise primarily from random combinations
of particles in continuum
e
e
!
q
q
events (
q
u;d;s;c
). We reduce these with requirements on the angle
T
between the thrust axis of the
B
candidate in the
4
S
frame and that of the rest of the charged tracks and neutral
calorimeter clusters in the event. The distribution is sharply
peaked near
j
cos
T
j
1
for
q
q
jet pairs, and nearly
uniform for
B
-meson decays. The requirement, which
optimizes the expected signal yield relative to its
background-dominated statistical error, is
j
cos
T
j
<
0
:
7
–
0
:
9
depending on the mode.
In the ML fit we discriminate further against
q
q
back-
ground with a Fisher discriminant
F
that combines several
variables which characterize the energy flow in the event
[1]. It provides about 1 standard deviation of separation
between
B
decay events and combinatorial background
[see Fig. 1(d)].
We also impose restrictions on decay angles to exclude
the most asymmetric decays where soft-particle back-
grounds concentrate and the acceptance changes rapidly.
We define the decay angle
k
dec
for a meson
k
as the angle
between the momenta of a daughter particle and the me-
son’s parent, measured in the meson’s rest frame. We
require for the
0
decays
j
cos
dec
j
<
0
:
9
and for
0
0
j
cos
0
dec
j
<
0
:
95
.For
B
0
!
0
the require-
ment is
j
cos
dec
j
<
0
:
86
to suppress the background
B
!
K
.
The average number of candidates found per selected
event is in the range 1.06 –1.23, depending on the final
state. We choose the candidate with the smallest value of a
2
constructed from the deviations from expected values of
one or more of the daughter resonance masses. From the
simulation we find that this algorithm selects the correct-
combination candidate in about two thirds of the events
containing multiple candidates, and that it induces negli-
gible bias.
We obtain yields for each channel from a maximum
likelihood fit with the input observables
E
,
m
ES
,
F
,
and
m
1
;
2
, the daughter invariant mass spectrum of the
and/or
0
candidate. The selected sample sizes are given in
the second column of Table II. Besides any signal events
they contain
q
q
(dominant) and
B
B
with
b
!
c
combina-
torial background, and a fraction that we estimate from the
simulation to be less than 0.2% of feed-across from other
charmless
B
B
modes. The latter events have ultimate final
states different from the signal, but with similar kinematics
so that broad peaks near those of the signal appear in some
observables, requiring a separate component in the proba-
bility density function (PDF). The likelihood function is
L
exp
X
j
Y
j
Y
N
i
X
j
Y
j
P
j
m
ES
i
P
j
E
i
P
j
F
i
P
j
m
i
1
P
j
m
i
2
;
(1)
where
N
is the number of events in the sample, and for each
component
j
,
Y
j
is the yield of events and
P
j
x
i
the PDF
for observable
x
in event
i
. For the modes
B
0
!
0
we
found no need for the
B
B
background component. The
factored form of the PDF indicated in Eq. (1) is a good
approximation, particularly for the combinatorial
q
q
com-
ponent, since correlations among observables measured in
the data (dominantly this component) are small.
Distortions of the fit results caused by this approximation
are measured in simulation and included in the bias cor-
rections and systematic errors discussed below.
We determine the PDFs for the signal and
B
B
back-
ground components from fits to MC data. We calibrate the
E [GeV]
∆
-0.3 -0.2 -0.1 0
0.1 0.2 0.3
Events / 40 MeV
0
50
100
150
200
250
300
350
400
(a)
[GeV]
ES
m
5.25
5.26
5.27
5.28
5.29
Events / 2 MeV
0
50
100
150
200
250
300
(b)
[GeV]
’
η
m
0.92 0.94 0.96 0.98
1
Events / 2.5 MeV
0
20
40
60
80
100
120
140
160
180
200
’
(c)
Fisher discriminant
-3 -2 -1 0
1
2
3
4
Events / bin
0
100
200
300
400
500
600
(d)
FIG. 1 (color online).
Plots of the
B
0
!
0
0
data distri-
bution projected on each of the fit variables: (a)
E
, (b)
m
ES
,
(c)
0
mass, and (d)
F
. The solid line represents the result of the
fit, and the dashed line the background contribution. (The
absence of signal here nearly hides the dashed curve.) The dotted
line illustrates the expected shape for signal, with a normaliza-
tion, chosen for clarity, that corresponds to a branching fraction
of
50
10
6
.
BRANCHING FRACTION LIMITS FOR
B
0
DECAYS TO
0
,
0
0
and
0
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-5
resolutions in
E
and
m
ES
with large control samples of
B
decays to charmed final states of similar topology (e.g.
B
!
D
K
). For the combinatorial background the
PDFs are determined in the fits to the data. However the
functional forms are first deduced from fits of that compo-
nent alone to sidebands in
m
ES
;
E
, so that we can
validate the fit before applying it to data containing the
signal.
We use the following functional forms for the PDFs:
sum of two Gaussians for
P
sig
m
ES
,
P
sig
;B
B
E
, and the
sharper structures in
P
B
B
m
ES
and
P
j
m
k
; linear or
quadratic dependences for combinatorial components of
P
B
B;q
q
m
k
and for
P
q
q
E
; and a conjunction of two
Gaussian segments below and above the peak with differ-
ent widths, plus a broad Gaussian, for
P
j
F
. The
q
q
background in
m
ES
is described by the function
x
1
x
2
p
exp
1
x
2
, with
x
2m
ES
=
s
p
and pa-
rameter
. These are discussed in more detail in [1], and
some of them are illustrated in Fig. 1.
We allow the parameters most important for the deter-
mination of the combinatorial background PDFs to vary in
the fit, along with the yields for all components.
Specifically, the free background parameters are most or
all of the following, depending on the decay mode:
for
m
ES
, linear and quadratic coefficients for
E
, area and
slope of the combinatorial component for
m
k
, and the
mean, width, and width difference parameters for
F
.
Results for the yields are presented in the third column
of Table II for each sample.
We test and calibrate the fitting procedure by applying it
to ensembles of simulated
q
q
experiments drawn from the
PDF into which we have embedded the expected number of
signal and
B
B
background events randomly extracted from
the fully simulated MC samples. We find biases of 0 – 2
events, somewhat dependent on the signal size. The bias
values obtained for simulations that reproduce the yields
found in the data are given in the fourth column of Table II.
In Fig. 1 we show, as representative of the several fits,
the projections of the PDF and data for the
B
0
!
0
0
sample. The goodness-of-fit is further demonstrated by the
distribution of the likelihood ratio
L
sig
=
L
sig
P
L
bkg
for data and for simulation generated from the PDF model,
shown for the same decay mode in Fig. 2. We see good
agreement between the model and the data. By construc-
tion the background is concentrated near zero, while any
signal would appear in a peak near one.
Likelihood ratio
0
0.2
0.4
0.6
0.8
1
Events / bin
1
10
2
10
3
10
Likelihood ratio
0
0.2
0.4
0.6
0.8
1
Events / bin
1
10
2
10
3
10
FIG. 2.
The likelihood ratio
L
sig
=
L
sig
P
L
bkg
for
B
0
!
0
0
. The open circles represent a simulated signal compo-
nent (normalized as the signal curves in Fig. 1), the solid points
represent the data, the solid histograms are from samples of
simulated background (shaded) and background plus signal
(white, barely visible in the right-most bins, given the small
signal yield).
TABLE II.
Number of events
N
in the sample, fitted signal yield
Y
S
in events (ev.), measured
bias, detection efficiency
, daughter branching fraction product (
Q
B
i
), and measured
branching fraction
B
for each decay chain, and for the combined measurements the significance
S
(with systematic uncertainties included), branching fraction with statistical and systematic
error, and in parentheses the 90% C.L. upper limits. The number of produced
B
B
pairs is
231
:
8
2
:
6
10
6
.
Mode
N
(ev.)
Y
S
(ev.)
Bias (ev.)
(%)
Q
B
i
(%)
S
(
)
B
10
6
0
3
539
2
:
0
3
:
1
2
:
0
1
:
9
1
:
0
13.8
3.95
0
:
1
2
:
4
1
:
6
0
1448
2
:
1
3
:
5
2
:
2
0
:
7
0
:
4
22.3
6.89
0
:
4
1
:
0
0
:
6
0
3
8268
8
:
6
8
:
7
7
:
0
0
:
0
0
:
4
14.9
6.67
3
:
8
3
:
8
3
:
0
0
16861
1
:
5
10
:
5
8
:
5
0
:
0
0
:
5
21.8
11.63
0
:
2
1
:
8
1
:
4
0
0
:
40
:
2
0
:
7
0
:
5
0
:
4
(
<
1
:
7
)
3
0
2334
10
:
3
8
:
6
6
:
7
1
:
2
0
:
7
16.3
22.6
1
:
1
1
:
0
0
:
8
0
5493
6
:
5
11
:
5
9
:
6
1
:
2
0
:
8
20.7
39.4
0
:
3
0
:
6
0
:
5
0
1
:
30
:
6
0
:
5
0
:
4
0
:
1
(
<
1
:
3
)
0
0
3663
7
:
9
6
:
9
5
:
2
1
:
2
0
:
6
20.7
17.5
1
:
40
:
8
0
:
8
0
:
6
0
:
1
(
<
2
:
1
)
B. AUBERT
et al.
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-6
We determine the reconstruction efficiencies, given in
Table II, as the ratio of reconstructed and accepted events
in simulation to the number generated. We compute the
branching fraction for each channel by subtracting the fit
bias from the measured yield, and dividing the result by the
efficiency and the number of produced
B
B
pairs [1]. We
assume equal decay rates of the
4
S
to
B
B
and
B
0
B
0
.
Table II gives the numbers pertinent to these computations.
The statistical error on the signal yield or branching frac-
tion is taken as the change in the central value when the
quantity
2ln
L
increases by one unit from its minimum
value.
We combine results where we have multiple decay
channels by adding the functions
2ln
f
L
B
=
L
B
0
G
B
;0
;
0
g
, where
B
0
is the central value from the fit,
0
is the systematic uncertainty, and
G
denotes convolution
with a Gaussian function. We give the resulting final
branching fractions for each mode in Table II with the
significance, taken as the square root of the difference
between the value of
2ln
L
(with additive systematic
uncertainties included) for zero signal and the value at its
minimum. The 90% C.L. upper limits are taken to be the
branching fraction below which lies 90% of the total of the
likelihood integral in the positive branching fraction
region.
The systematic uncertainties on the branching fractions
arising from lack of knowledge of the PDFs have been
included in part in the statistical error since most back-
ground parameters are free in the fit. For the signal, the
uncertainties in PDF parameters are estimated from the
consistency of fits to MC and data in control modes.
Varying the signal-PDF parameters within these errors,
we estimate yield uncertainties of 0 – 2 events, depending
on the mode. The uncertainty from fit bias (Table II)
includes its statistical uncertainty from the simulated ex-
periments, and half of the correction itself, added in quad-
rature. Similarly we estimate the uncertainty from
modeling the
B
B
backgrounds by taking half of the con-
tribution of that component to the fitted signal yield, 0.2 –
1.2 events. These additive systematic errors are dominant
for these modes with little or no signal yield.
Uncertainties in our knowledge of the efficiency, found
from auxiliary studies, include
0
:
8%
N
t
and
1
:
5%
N
,
where
N
t
and
N
are the number of tracks and photons,
respectively, in the
B
candidate. The uncertainty in the total
number of
B
B
pairs in the data sample is 1.1%. Published
data [17] provide the uncertainties in the
B
-daughter prod-
uct branching fractions (0.7– 3.9%). The uncertainties in
the efficiency from the event selection are about 1%.
After combining the measurements we obtain the central
values and 90% C.L. upper limits for the branching frac-
tions:
B
B
0
!
0
0
:
2
0
:
7
0
:
5
0
:
4
10
6
<
1
:
7
10
6
;
B
B
0
!
0
0
:
6
0
:
5
0
:
4
0
:
1
10
6
<
1
:
3
10
6
;
and
B
B
0
!
0
0
0
:
8
0
:
8
0
:
6
0
:
1
10
6
<
2
:
1
10
6
:
We find no evidence for these decays, and our upper limits
represent two to three-fold improvement over the previous
measurements [1,2,18]. The range of sensitivity of these
measurements is comparable to the range of the theoretical
estimates.
These results can be used to constrain the expected value
of the
CP
asymmetry
S
f
in relation to
sin2
for the decay
B
0
!
0
K
0
[7,9,10]. Using the method proposed by
Gronau
et al.
[10], we estimate that our results will provide
approximately 20% improvement of the prediction for the
contribution of the color-suppressed tree amplitude in
B
0
!
0
K
0
decays. This translates into a 20% reduction
of this theoretical uncertainty in
S
0
K
0
S
. We find a similar
improvement in the corresponding uncertainty of
sin2
measured with
B
0
!
decays [12,13].
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), IHEP (China), CEA and CNRS-IN2P3 (France),
BMBF and DFG (Germany), INFN (Italy), FOM (The
Netherlands), NFR (Norway), MIST (Russia), and
PPARC (United Kingdom). Individuals have received sup-
port from CONACyT (Mexico), Marie Curie EIF
(European Union), the A. P. Sloan Foundation, the
Research Corporation, and the Alexander von Humboldt
Foundation.
[1] B. Aubert
et al.
(
BABAR
Collaboration), Phys. Rev. D
70
,
032006 (2004).
[2] B. Aubert
et al.
(
BABAR
Collaboration), Phys. Rev. Lett.
93
, 181806 (2004).
[3] M. Beneke
et al.
, Nucl. Phys.
B591
, 313 (2000).
[4] M. Beneke and M. Neubert, Nucl. Phys.
B675
, 333 (2003).
[5] H. Wang
et al.
, Nucl. Phys.
B738
, 243 (2006).
[6] A. Williamson and J. Zupan, hep-ph/0601214.
[7] C. W. Chiang, M. Gronau, and J. L. Rosner, Phys. Rev. D
68
, 074012 (2003).
BRANCHING FRACTION LIMITS FOR
B
0
DECAYS TO
0
,
0
0
and
0
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-7
[8] C. W. Chiang, M. Gronau, and J. L. Rosner, Phys. Rev. D
70
, 034020 (2004).
[9] Y. Grossman
et al.
, Phys. Rev. D
68
, 015004 (2003).
[10] M. Gronau, J. L. Rosner, and J. Zupan, Phys. Lett. B
596
,
107 (2004).
[11] B. Aubert
et al.
(
BABAR
Collaboration), Phys. Rev. Lett.
94
, 161803 (2005); K. Abe
et al.
(Belle Collaboration),
Phys. Rev. D
71
, 072003 (2005).
[12] M. Gronau and J. Zupan, Phys. Rev. D
71
, 074017 (2005).
[13] S. Gardner, Phys. Rev. D
72
, 034015 (2005).
[14] B. Aubert
et al.
(
BABAR
Collaboration), Nucl. Instrum.
Methods Phys. Res., Sect. A
479
, 1 (2002).
[15] PEP-II Conceptual Design Report, SLAC Report No. R-
418, 1993 (to be published).
[16] The
BABAR
detector Monte Carlo simulation is based on
GEANT4: S. Agostinelli
et al.
, Nucl. Instrum. Methods
Phys. Res., Sect. A
506
, 250 (2003).
[17] S. Eidelman
et al.
(Particle Data Group), Phys. Lett. B
592
, 1 (2004).
[18] P. Chang
et al.
, Phys. Rev. D
71
, 091106 (2005).
B. AUBERT
et al.
PHYSICAL REVIEW D
73,
071102 (2006)
RAPID COMMUNICATIONS
071102-8