Study of hadronic transitions between
states and observation of
ð
4
S
Þ!
ð
1
S
Þ
decay
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. Kukartsev,
5
G. Lynch,
5
I. L. Osipenkov,
5
M. T. Ronan,
5,
*
K. Tackmann,
5
T. Tanabe,
5
C. M. Hawkes,
6
N. Soni,
5
A. T. Watson,
5
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
L. Teodorescu,
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
A. Kreisel,
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
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. S. Bailey,
43
R. J. Barlow,
43
Y. M. Chia,
43
C. L. Edgar,
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. 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
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
J. Biesiada,
62
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
PHYSICAL REVIEW D
78,
112002 (2008)
1550-7998
=
2008
=
78(11)
=
112002(11)
112002-1
Ó
2008 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
W. Roethel,
65
F. F. Wilson,
65
S. Emery,
66
M. Escalier,
66
L. Esteve,
66
A. Gaidot,
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
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, 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 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, 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, I-16146 Genova, Italy
28b
Dipartimento di Fisica, Universita
`
di Genova, I-16146 Genova, Italy
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
B. AUBERT
et al.
PHYSICAL REVIEW D
78,
112002 (2008)
112002-2
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, Canada H3A 2T8
48a
INFN Sezione di Milano, 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, 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, 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, I-06100 Perugia, Italy
60b
Dipartimento di Fisica, Universita
`
di Perugia, I-06100 Perugia, Italy
61a
INFN Sezione di Pisa, I-56127 Pisa, Italy
61b
Dipartimento di Fisica, 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, 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
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
74a
INFN Sezione di Torino, I-10125 Torino, Italy
74b
Dipartimento di Fisica Sperimentale, Universita
`
di Torino, I-10125 Torino, Italy
75a
INFN Sezione di Trieste, I-34127 Trieste, Italy
75b
Dipartimento di Fisica, Universita
`
di Trieste, I-34127 Trieste, Italy
*
Deceased
k
Also with Universita
`
di Roma La Sapienza, I-00185 Roma, Italy.
x
Also with Universita
`
di Perugia, Dipartimento di Fisica, Perugia, Italy.
‡
Now at Tel Aviv University, Tel Aviv, 69978, Israel.
+
Now at Temple University, Philadelphia, PA 19122, USA.
{
Now at University of South Alabama, Mobile, AL 36688, USA.
STUDY OF HADRONIC TRANSITIONS BETWEEN
...
PHYSICAL REVIEW D
78,
112002 (2008)
112002-3
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
(Received 13 July 2008; published 11 December 2008)
We present a study of hadronic transitions between
ð
mS
Þ
(
m
¼
4
, 3, 2) and
ð
nS
Þ
(
n
¼
2
,1)
resonances based on
347
:
5fb
1
of data taken with the
BABAR
detector at the PEP-II storage rings. We
report the first observation of
ð
4
S
Þ!
ð
1
S
Þ
decay with a branching fraction
B
ð
ð
4
S
Þ!
ð
1
S
ÞÞ¼
ð
1
:
96
0
:
06
stat
0
:
09
syst
Þ
10
4
and measure the ratio of partial widths
ð
ð
4
S
Þ!
ð
1
S
ÞÞ
=
ð
ð
4
S
Þ!
þ
ð
1
S
ÞÞ¼
2
:
41
0
:
40
stat
0
:
12
syst
. We set 90% CL upper limits on the ratios
ð
ð
2
S
Þ!
ð
1
S
ÞÞ
=
ð
ð
2
S
Þ!
þ
ð
1
S
ÞÞ
<
5
:
2
10
3
and
ð
ð
3
S
Þ!
ð
1
S
ÞÞ
=
ð
ð
3
S
Þ!
þ
ð
1
S
ÞÞ
<
1
:
9
10
2
. We also present new measurements of the ratios
ð
ð
4
S
Þ!
þ
ð
2
S
ÞÞ
=
ð
ð
4
S
Þ!
þ
ð
1
S
ÞÞ¼
1
:
16
0
:
16
stat
0
:
14
syst
and
ð
ð
3
S
Þ!
þ
ð
2
S
ÞÞ
=
ð
ð
3
S
Þ!
þ
ð
1
S
ÞÞ¼
0
:
577
0
:
026
stat
0
:
060
syst
.
DOI:
10.1103/PhysRevD.78.112002
PACS numbers: 14.40.Gx, 13.25.Gv
I. INTRODUCTION
Hadronic transitions between bound states of heavy
quarkonia [
1
] are generally studied using the QCD multi-
pole expansion model (QCDME) [
2
]. This succeeds in
explaining the relative rates of the
c
ð
2
S
Þ!
J=
c
and
c
ð
2
S
Þ!
J=
c
transitions and the
invariant mass
distributions in
c
ð
2
S
Þ!
J=
c
,
ð
2
S
Þ!
ð
1
S
Þ
,
ð
3
S
Þ!
ð
2
S
Þ
and the recently observed
ð
4
S
Þ!
þ
ð
1
S
Þ
decays [
3
,
4
]. Until recently the only feature
that QCDME could not explain was the dipion invariant
mass distribution in the
ð
3
S
Þ!
ð
1
S
Þ
transition [
5
],
for which a number of possible explanations have been
proposed [
6
]. The dipion invariant mass distribution in
ð
4
S
Þ!
þ
ð
2
S
Þ
[
3
] is also in disagreement with
the QCDME prediction and was not predicted either by
the alternative explanations proposed for the
ð
3
S
Þ!
þ
ð
1
S
Þ
. This implies that additional experimental
input is needed to understand hadronic transitions. In
QCDME the gluon radiation from a heavy
q
q
bound state
is calculated in terms of chromo-electric and chromo-
magnetic fields, in analogy to electromagnetism.
Transitions between colorless hadrons require the emission
of at least two gluons. The
ð
mS
Þ!
ð
nS
Þ
transitions
(
m
3
S
1
!
n
3
S
1
in spectroscopic notation [
7
]) are
E1E1, i.e. transitions where both gluons are in an E1 state.
The decays
ð
mS
Þ!
ð
nS
Þ
(
m
3
S
1
!
n
3
S
1
) proceed
either via E1M2 or M1M1 transitions; the E1M2 transition
is expected to dominate. The
b
b
system offers unique
opportunities: there are five known
m
3
S
1
!
n
3
S
1
tran-
sitions and also four kinematically allowed transitions
involving an
meson. Of the latter only the
ð
2
S
Þ!
ð
1
S
Þ
has been recently observed by CLEO [
8
], with a
branching fraction
B
ð
ð
2
S
Þ!
ð
1
S
ÞÞ¼ð
2
:
1
þ
0
:
7
0
:
6
0
:
5
Þ
10
4
.
In this paper we present improved measurements of the
ð
4
S
Þ!
ð
nS
Þ
transitions, a search for
ð
mS
Þ!
ð
1
S
Þ
and new measurements of
ð
3
S
Þ!
þ
ð
nS
Þ
and
ð
2
S
Þ!
þ
ð
1
S
Þ
partial widths.
We also measure the ratios of partial widths
ð
ð
mS
Þ!
ð
1
S
ÞÞ
=
ð
ð
mS
Þ!
þ
ð
1
S
ÞÞ
and
ð
ð
mS
Þ!
þ
ð
2
S
ÞÞ
=
ð
ð
mS
Þ!
þ
ð
1
S
ÞÞ
(
m
¼
3
, 4), for
which a number of systematic uncertainties cancel.
The
ð
mS
Þ!
þ
ð
nS
Þ
and
ð
mS
Þ!
ð
nS
Þ
transitions, denoted by
mS
!
nS
and
mS
!
nS
,
respectively, are studied by reconstructing the
ð
nS
Þ
me-
sons via their leptonic decay to
þ
or
e
þ
e
. The
meson is reconstructed via its
þ
0
decay. With the
choice of this particular
decay mode all final states
contain the same charged particles, resulting in larger
cancellations of the systematic uncertainties for the ratios
of partial widths. Events where the
decays to
are not
considered in this work because the
‘‘
final state has a
smaller signal to background ratio than the
‘
þ
‘
þ
0
final state.
II. DATA SAMPLES AND DETECTOR
We search for
ð
4
S
Þ
hadronic transitions using a sample
of
ð
383
:
2
4
:
2
Þ
10
6
ð
4
S
Þ
decays corresponding to an
integrated luminosity,
L
int
on
,of
347
:
5fb
1
acquired near the
peak of the
ð
4
S
Þ
resonance (‘‘on-peak,’’ nominal center-
of-mass energy,
ffiffiffi
s
p
of about 10.58 GeV) with the
BABAR
detector at the PEP-II asymmetric-energy
e
þ
e
storage
rings at SLAC. In addition, a data sample corresponding to
L
int
off
¼
36
:
6fb
1
, collected approximately 40 MeV below
the resonance (‘‘off-peak’’) is used to study some of the
backgrounds. Decays of
ð
3
S
Þ
and
ð
2
S
Þ
are studied in
events recorded ‘‘on-peak’’ and selected with an initial
state radiation (ISR) photon. The ISR photon, preferen-
tially emitted at small angle along the beam direction, is
not required to be detected.
The
BABAR
detector is described in detail elsewhere [
9
].
Charged-particle momenta are measured in a tracking
system consisting of a five-layer double-sided silicon ver-
tex tracker (SVT) and a 40-layer central drift chamber
**
Also with Universita
`
di Sassari, Sassari, Italy.
B. AUBERT
et al.
PHYSICAL REVIEW D
78,
112002 (2008)
112002-4
(DCH), both embedded in a 1.5-T axial magnetic field.
Charged-particle identification is based on the specific
energy loss measured in the SVT and DCH, and on a
measurement of the photons produced in the fused-silica
bars of the ring-imaging Cherenkov detector (DIRC). A
CsI(Tl) electromagnetic calorimeter (EMC) is used to
detect and identify photons and electrons, while muons
are identified in the instrumented flux return of the magnet
(IFR).
Simulated Monte Carlo (MC) events are generated using
the EvtGen package [
10
]. The angular distribution of gen-
erated dilepton decays incorporates the
ð
nS
Þ
polarization,
while dipion transitions are generated according to phase
space. In the simulation of
mS
!
1
S
we use the angular
distribution dictated by the quantum numbers for a vector
decay to a pseudoscalar and a vector. Secondary photon
emission is taken into account in the simulation of
ð
mS
Þ
produced in ISR. Simulated events are passed through a
detector simulation based on GEANT4 [
11
], and analyzed
in the same manner as data.
III. EVENT SELECTION
The events of interest have a lepton pair from the decay
of the
ð
nS
Þ
resonance of invariant mass,
M
‘‘
, compatible
with the known mass values of the
ð
nS
Þ
[
12
],
M
ð
nS
Þ
, and
a pair of oppositely charged pions.
The signature for
mS
!
nS
transition events is an
invariant mass difference
M
¼
M
‘‘
M
‘‘
compatible
with the difference of the masses of the two
resonances,
M
ð
mS
Þ
M
ð
nS
Þ
, where
M
‘‘
is the
þ
‘
þ
‘
invari-
ant mass.
The
mS
!
nS
events have two additional photons
from the
0
decay, a
þ
0
invariant mass,
m
3
, com-
patible with the known
mass,
M
ð
Þ
, and an invariant
mass difference,
M
¼
M
3
‘‘
M
‘‘
m
3
compatible
with
M
ð
mS
Þ
M
ð
nS
Þ
M
ð
Þ
, where
M
3
‘‘
is the
þ
0
‘
þ
‘
invariant mass.
The rms widths of the reconstructed
M
‘‘
,
m
3
,
M
, and
M
distributions are of the order of
75 MeV
=c
2
,
12 MeV
=c
2
,
7 MeV
=c
2
and
10 MeV
=c
2
, respectively.
Events in the data sample with
M
‘‘
within
350 MeV
=c
2
of the known
M
ð
nS
Þ
values and
M
within
60 MeV
=c
2
of
the values expected for any of the
mS
!
nS
transitions
were not examined until the event selection criteria were
finalized. Events outside these regions were used to under-
stand the background. Simulated MC events were used to
model the signal.
Candidate events have at least 4 charged tracks with a
polar angle
within the fiducial volume of the tracking
system (
0
:
41
<<
2
:
54 rad
). Each lepton candidate is
required to have a center-of-mass momentum between
4
:
20 GeV
=c
and
5
:
25 GeV
=c
. At least one of the muons
of
ð
nS
Þ!
þ
candidates must be compatible with
the muon hypothesis based on the energy deposited in the
EMC and the hit pattern in the IFR along the track trajec-
tory. Similarly at least one of the electrons of
ð
nS
Þ!
e
þ
e
candidates must be compatible with the electron
hypothesis based on the energy deposit in the EMC, the
ratio of energy in the EMC to the track momentum, and the
energy loss in the detector material. We require
M
½
M
ee
to be within
200
½
350
;
þ
200
MeV
=c
2
of the nominal
ð
1
S
Þ
or
ð
2
S
Þ
mass. The asymmetric cut in the
e
þ
e
sample is due to bremsstrahlung, which causes a long tail
in the reconstructed
M
ee
distribution at low invariant
masses and that is partially recovered by an algorithm
that combines the energy of electron tracks with the energy
of nearby photons.
Pairs of oppositely charged tracks, not identified as
electrons and whose Cherenkov angle in the DIRC, when
measured, is within
3
of the value expected for a pion, are
selected to form a dipion candidate. The dilepton and the
dipion are constrained to a common vertex and the vertex
fit is required to have a
2
probability larger than
10
3
.
A large fraction of the remaining background is due to
e
þ
e
and
þ
events where a photon converts in the
detector material and the leptons are reconstructed as
pions. To reduce this background we reject events where
the opening angle of the charged pion candidates in the
laboratory reference frame has
cos
þ
>
0
:
95
, or where
the invariant mass of the charged tracks associated with the
pion candidates, calculated assuming the
e
mass hypothe-
sis, satisfies
m
conv
<
50 MeV
=c
2
. The distribution of
M
‘‘
vs
M
for candidate events after the preliminary selection
is shown in Fig.
1
.
In the case of
ð
4
S
Þ!
ð
nS
Þ
transitions the back-
ground is larger and the expected signal smaller. For this
reason we further restrict our selection to events where at
least one of the two charged pions has a transverse mo-
mentum greater than
100 MeV
=c
,
m
conv
>
100 MeV
=c
2
,
and the polar angle in the laboratory system of the
e
from
ð
nS
Þ!
e
þ
e
is larger than 0.7 rad, to reject radiative
Bhabha events.
Events with at least two candidate photons of
E
>
50 MeV
and invariant mass
110
<m
<
150 MeV
=c
2
are considered to be
nS
candidates if the
þ
0
invariant mass is within
35 MeV
=c
2
of the known
mass. To suppress possible cross-feed from the high sta-
tistics
mS
!
nS
transitions we require that
mS
!
nS
candidates have
M
more than
20 MeV
=c
2
(
3
) from any of the known
M
ð
mS
Þ
M
ð
nS
Þ
values.
We select
ð
2
S
Þ
and
ð
3
S
Þ
states produced via ISR,
requiring that the momentum of the reconstructed
‘
þ
‘
þ
½
0
in the center-of-mass rest frame,
p
cand
,
is within
150 MeV
=c
of the expected value of
ð
s
M
2
ð
mS
ÞÞ
=
ð
2
ffiffiffi
s
p
Þ
.For
ð
4
S
Þ
decays
p
cand
is required to be
<
200 MeV
=c
.
The average efficiency for each of the transitions is
given in Table
I
. The efficiency for the
þ
½
0
e
þ
e
final state is in all cases smaller than for the
þ
½
0
þ
final state due to a trigger-level ineffi-
STUDY OF HADRONIC TRANSITIONS BETWEEN
...
PHYSICAL REVIEW D
78,
112002 (2008)
112002-5