of 13
arXiv:1407.7244v2 [hep-ex] 15 Dec 2014
B
A
B
AR
-PUB-13/019
SLAC-PUB-16048
Study of
B
±
,
0
J/ψK
+
K
K
±
,
0
and search for
B
0
J/ψφ
at
B
A
B
AR
J. P. Lees, V. Poireau, and V. Tisserand
Laboratoire d’Annecy-le-Vieux de Physique des Particules
(LAPP),
Universit ́e de Savoie, CNRS/IN2P3, F-74941 Annecy-Le-Vie
ux, France
E. Grauges
Universitat de Barcelona, Facultat de Fisica, Departament
ECM, E-08028 Barcelona, Spain
A. Palano
ab
INFN Sezione di Bari
a
; Dipartimento di Fisica, Universit`a di Bari
b
, I-70126 Bari, Italy
G. Eigen and B. Stugu
University of Bergen, Institute of Physics, N-5007 Bergen,
Norway
D. N. Brown, L. T. Kerth, Yu. G. Kolomensky, M. J. Lee, and G. Lyn
ch
Lawrence Berkeley National Laboratory and University of Ca
lifornia, Berkeley, California 94720, USA
H. Koch and T. Schroeder
Ruhr Universit ̈at Bochum, Institut f ̈ur Experimentalphys
ik 1, D-44780 Bochum, Germany
C. Hearty, T. S. Mattison, J. A. McKenna, and R. Y. So
University of British Columbia, Vancouver, British Columb
ia, Canada V6T 1Z1
A. Khan
Brunel University, Uxbridge, Middlesex UB8 3PH, United Kin
gdom
V. E. Blinov
ac
, A. R. Buzykaev
a
, V. P. Druzhinin
ab
, V. B. Golubev
ab
, E. A. Kravchenko
ab
, A. P. Onuchin
ac
,
S. I. Serednyakov
ab
, Yu. I. Skovpen
ab
, E. P. Solodov
ab
, K. Yu. Todyshev
ab
, and A. N. Yushkov
a
Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630
090
a
,
Novosibirsk State University, Novosibirsk 630090
b
,
Novosibirsk State Technical University, Novosibirsk 6300
92
c
, Russia
A. J. Lankford and M. Mandelkern
University of California at Irvine, Irvine, California 926
97, USA
B. Dey, J. W. Gary, and O. Long
University of California at Riverside, Riverside, Califor
nia 92521, USA
C. Campagnari, M. Franco Sevilla, T. M. Hong, D. Kovalskyi, J. D. Rich
man, and C. A. West
University of California at Santa Barbara, Santa Barbara, C
alifornia 93106, USA
A. M. Eisner, W. S. Lockman, W. Panduro Vazquez, B. A. Schumm, a
nd A. Seiden
University of California at Santa Cruz, Institute for Parti
cle Physics, Santa Cruz, California 95064, USA
D. S. Chao, C. H. Cheng, B. Echenard, K. T. Flood, D. G. Hitlin, T. S.
Miyashita, P. Ongmongkolkul, and F. C. Porter
California Institute of Technology, Pasadena, California
91125, USA
R. Andreassen, Z. Huard, B. T. Meadows, B. G. Pushpawela, M. D.
Sokoloff, and L. Sun
University of Cincinnati, Cincinnati, Ohio 45221, USA
P. C. Bloom, W. T. Ford, A. Gaz, U. Nauenberg, J. G. Smith, and S. R
. Wagner
University of Colorado, Boulder, Colorado 80309, USA
R. Ayad
a
and W. H. Toki
2
Colorado State University, Fort Collins, Colorado 80523, U
SA
B. Spaan
Technische Universit ̈at Dortmund, Fakult ̈at Physik, D-44
221 Dortmund, Germany
R. Schwierz
Technische Universit ̈at Dresden, Institut f ̈ur Kern- und T
eilchenphysik, D-01062 Dresden, Germany
D. Bernard and M. Verderi
Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS
/IN2P3, F-91128 Palaiseau, France
S. Playfer
University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
D. Bettoni
a
, C. Bozzi
a
, R. Calabrese
ab
, G. Cibinetto
ab
, E. Fioravanti
ab
,
I. Garzia
ab
, E. Luppi
ab
, L. Piemontese
a
, and V. Santoro
a
INFN Sezione di Ferrara
a
; Dipartimento di Fisica e Scienze della Terra, Universit`a
di Ferrara
b
, I-44122 Ferrara, Italy
A. Calcaterra, R. de Sangro, G. Finocchiaro, S. Martellotti,
P. Patteri, I. M. Peruzzi,
b
M. Piccolo, M. Rama, and A. Zallo
INFN Laboratori Nazionali di Frascati, I-00044 Frascati, I
taly
R. Contri
ab
, E. Guido
ab
, M. Lo Vetere
ab
, M. R. Monge
ab
, S. Passaggio
a
, C. Patrignani
ab
, and E. Robutti
a
INFN Sezione di Genova
a
; Dipartimento di Fisica, Universit`a di Genova
b
, I-16146 Genova, Italy
B. Bhuyan and V. Prasad
Indian Institute of Technology Guwahati, Guwahati, Assam,
781 039, India
M. Morii
Harvard University, Cambridge, Massachusetts 02138, USA
A. Adametz and U. Uwer
Universit ̈at Heidelberg, Physikalisches Institut, D-691
20 Heidelberg, Germany
H. M. Lacker
Humboldt-Universit ̈at zu Berlin, Institut f ̈ur Physik, D-
12489 Berlin, Germany
P. D. Dauncey
Imperial College London, London, SW7 2AZ, United Kingdom
U. Mallik
University of Iowa, Iowa City, Iowa 52242, USA
C. Chen, J. Cochran, W. T. Meyer, and S. Prell
Iowa State University, Ames, Iowa 50011-3160, USA
H. Ahmed
Physics Department, Jazan University, Jazan 22822, Kingdo
m of Saudia Arabia
A. V. Gritsan
Johns Hopkins University, Baltimore, Maryland 21218, USA
N. Arnaud, M. Davier, D. Derkach, G. Grosdidier, F. Le Diberder,
A. M. Lutz, B. Malaescu,
c
P. Roudeau, A. Stocchi, and G. Wormser
Laboratoire de l’Acc ́el ́erateur Lin ́eaire, IN2P3/CNRS et
Universit ́e Paris-Sud 11,
Centre Scientifique d’Orsay, F-91898 Orsay Cedex, France
D. J. Lange and D. M. Wright
3
Lawrence Livermore National Laboratory, Livermore, Calif
ornia 94550, USA
J. P. Coleman, J. R. Fry, E. Gabathuler, D. E. Hutchcroft, D. J. P
ayne, and C. Touramanis
University of Liverpool, Liverpool L69 7ZE, United Kingdom
A. J. Bevan, F. Di Lodovico, and R. Sacco
Queen Mary, University of London, London, E1 4NS, United Kin
gdom
G. Cowan
University of London, Royal Holloway and Bedford New Colleg
e, Egham, Surrey TW20 0EX, United Kingdom
J. Bougher, D. N. Brown, and C. L. Davis
University of Louisville, Louisville, Kentucky 40292, USA
A. G. Denig, M. Fritsch, W. Gradl, K. Griessinger, A. Hafner, E. Pre
ncipe,
d
and K. R. Schubert
Johannes Gutenberg-Universit ̈at Mainz, Institut f ̈ur Ker
nphysik, D-55099 Mainz, Germany
R. J. Barlow
e
and G. D. Lafferty
University of Manchester, Manchester M13 9PL, United Kingd
om
R. Cenci, B. Hamilton, A. Jawahery, and D. A. Roberts
University of Maryland, College Park, Maryland 20742, USA
R. Cowan, D. Dujmic, and G. Sciolla
Massachusetts Institute of Technology, Laboratory for Nuc
lear Science, Cambridge, Massachusetts 02139, USA
R. Cheaib, P. M. Patel,
f
and S. H. Robertson
McGill University, Montr ́eal, Qu ́ebec, Canada H3A 2T8
P. Biassoni
ab
, N. Neri
a
, and F. Palombo
ab
INFN Sezione di Milano
a
; Dipartimento di Fisica, Universit`a di Milano
b
, I-20133 Milano, Italy
L. Cremaldi, R. Godang,
g
P. Sonnek, and D. J. Summers
University of Mississippi, University, Mississippi 38677
, USA
M. Simard and P. Taras
Universit ́e de Montr ́eal, Physique des Particules, Montr ́
eal, Qu ́ebec, Canada H3C 3J7
G. De Nardo
ab
, D. Monorchio
ab
, G. Onorato
ab
, and C. Sciacca
ab
INFN Sezione di Napoli
a
; Dipartimento di Scienze Fisiche,
Universit`a di Napoli Federico II
b
, I-80126 Napoli, Italy
M. Martinelli and G. Raven
NIKHEF, National Institute for Nuclear Physics and High Ene
rgy Physics, NL-1009 DB Amsterdam, The Netherlands
C. P. Jessop and J. M. LoSecco
University of Notre Dame, Notre Dame, Indiana 46556, USA
K. Honscheid and R. Kass
Ohio State University, Columbus, Ohio 43210, USA
J. Brau, R. Frey, N. B. Sinev, D. Strom, and E. Torrence
University of Oregon, Eugene, Oregon 97403, USA
E. Feltresi
ab
, M. Margoni
ab
, M. Morandin
a
, M. Posocco
a
, M. Rotondo
a
, G. Simi
ab
, F. Simonetto
ab
, and R. Stroili
ab
INFN Sezione di Padova
a
; Dipartimento di Fisica, Universit`a di Padova
b
, I-35131 Padova, Italy
S. Akar, E. Ben-Haim, M. Bomben, G. R. Bonneaud, H. Briand,
4
G. Calderini, J. Chauveau, Ph. Leruste, G. Marchiori, J. Ocariz, an
d S. Sitt
Laboratoire de Physique Nucl ́eaire et de Hautes Energies,
IN2P3/CNRS, Universit ́e Pierre et Marie Curie-Paris6,
Universit ́e Denis Diderot-Paris7, F-75252 Paris, France
M. Biasini
ab
, E. Manoni
a
, S. Pacetti
ab
, and A. Rossi
a
INFN Sezione di Perugia
a
; Dipartimento di Fisica, Universit`a di Perugia
b
, I-06123 Perugia, Italy
C. Angelini
ab
, G. Batignani
ab
, S. Bettarini
ab
, M. Carpinelli
ab
,
h
G. Casarosa
ab
, A. Cervelli
ab
, M. Chrzaszcz
ab
,
F. Forti
ab
, M. A. Giorgi
ab
, A. Lusiani
ac
, B. Oberhof
ab
, E. Paoloni
ab
, A. Perez
a
, G. Rizzo
ab
, and J. J. Walsh
a
INFN Sezione di Pisa
a
; Dipartimento di Fisica, Universit`a di Pisa
b
; Scuola Normale Superiore di Pisa
c
, I-56127 Pisa, Italy
D. Lopes Pegna, J. Olsen, and A. J. S. Smith
Princeton University, Princeton, New Jersey 08544, USA
R. Faccini
ab
, F. Ferrarotto
a
, F. Ferroni
ab
, M. Gaspero
ab
, L. Li Gioi
a
, and G. Piredda
a
INFN Sezione di Roma
a
; Dipartimento di Fisica,
Universit`a di Roma La Sapienza
b
, I-00185 Roma, Italy
C. B ̈unger, S. Dittrich, O. Gr ̈unberg, T. Hartmann, T. Leddig, C
. Voß, and R. Waldi
Universit ̈at Rostock, D-18051 Rostock, Germany
T. Adye, E. O. Olaiya, and F. F. Wilson
Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX
11 0QX, United Kingdom
S. Emery and G. Vasseur
CEA, Irfu, SPP, Centre de Saclay, F-91191 Gif-sur-Yvette, F
rance
F. Anulli,
i
D. Aston, D. J. Bard, J. F. Benitez, C. Cartaro, M. R. Convery, J
. Dorfan, G. P. Dubois-Felsmann,
W. Dunwoodie, M. Ebert, R. C. Field, B. G. Fulsom, A. M. Gabareen, M
. T. Graham, C. Hast,
W. R. Innes, P. Kim, M. L. Kocian, D. W. G. S. Leith, P. Lewis, D. Linde
mann, B. Lindquist, S. Luitz,
V. Luth, H. L. Lynch, D. B. MacFarlane, D. R. Muller, H. Neal, S. Nels
on, M. Perl, T. Pulliam,
B. N. Ratcliff, A. Roodman, A. A. Salnikov, R. H. Schindler, A. Snyder
, D. Su, M. K. Sullivan, J. Va’vra,
A. P. Wagner, W. F. Wang, W. J. Wisniewski, M. Wittgen, D. H. Wright,
H. W. Wulsin, and V. Ziegler
SLAC National Accelerator Laboratory, Stanford, Californ
ia 94309 USA
M. V. Purohit, R. M. White,
j
and J. R. Wilson
University of South Carolina, Columbia, South Carolina 292
08, USA
A. Randle-Conde and S. J. Sekula
Southern Methodist University, Dallas, Texas 75275, USA
M. Bellis, P. R. Burchat, and E. M. T. Puccio
Stanford University, Stanford, California 94305-4060, US
A
M. S. Alam and J. A. Ernst
State University of New York, Albany, New York 12222, USA
R. Gorodeisky, N. Guttman, D. R. Peimer, and A. Soffer
Tel Aviv University, School of Physics and Astronomy, Tel Av
iv, 69978, Israel
S. M. Spanier
University of Tennessee, Knoxville, Tennessee 37996, USA
J. L. Ritchie, A. M. Ruland, R. F. Schwitters, and B. C. Wray
University of Texas at Austin, Austin, Texas 78712, USA
J. M. Izen and X. C. Lou
5
University of Texas at Dallas, Richardson, Texas 75083, USA
F. Bianchi
ab
, F. De Mori
ab
, A. Filippi
a
, D. Gamba
ab
, and S. Zambito
ab
INFN Sezione di Torino
a
; Dipartimento di Fisica, Universit`a di Torino
b
, I-10125 Torino, Italy
L. Lanceri
ab
and L. Vitale
ab
INFN Sezione di Trieste
a
; Dipartimento di Fisica, Universit`a di Trieste
b
, I-34127 Trieste, Italy
F. Martinez-Vidal, A. Oyanguren, and P. Villanueva-Perez
IFIC, Universitat de Valencia-CSIC, E-46071 Valencia, Spa
in
J. Albert, Sw. Banerjee, F. U. Bernlochner, H. H. F. Choi, G. J. Kin
g, R. Kowalewski,
M. J. Lewczuk, T. Lueck, I. M. Nugent, J. M. Roney, R. J. Sobie, a
nd N. Tasneem
University of Victoria, Victoria, British Columbia, Canad
a V8W 3P6
T. J. Gershon, P. F. Harrison, and T. E. Latham
Department of Physics, University of Warwick, Coventry CV4
7AL, United Kingdom
H. R. Band, S. Dasu, Y. Pan, R. Prepost, and S. L. Wu
University of Wisconsin, Madison, Wisconsin 53706, USA
We study the rare
B
meson decays
B
±
,
0
J/ψK
+
K
K
±
,
0
,
B
±
,
0
J/ψφK
±
,
0
, and search for
B
0
J/ψφ
, using 469 million
B
B
events collected at the
Υ
(4
S
) resonance with the
B
A
B
AR
detector
at the PEP-II
e
+
e
asymmetric-energy collider. We present new measurements o
f branching
fractions and a study of the
J/ψφ
mass distribution in search of new charmonium-like states.
In
addition, we search for the decay
B
0
J/ψφ
, and find no evidence of a signal.
PACS numbers: 13.25.Hw, 12.15.Hh, 11.30.Er
I. INTRODUCTION
Many charmonium-like resonances have been discov-
ered in the past, revealing a spectrum too rich to in-
terpret in terms of conventional mesons expected from
potential models [1]. In several cases, it has not been
possible to assign a spin-parity value to the resonance.
Some of them have been extensively investigated as pos-
sible candidates for non-conventional mesons, such as
tetraquarks, glueballs, or hybrids [2].
In a search for exotic states, the CDF experiment stud-
ied the decay
B
+
J/ψφK
+
[3], where
J/ψ
μ
+
μ
and
φ
(1020)
K
+
K
, claiming the observation of a res-
a
Now at the University of Tabuk, Tabuk 71491, Saudi Arabia
b
Also with Universit`a di Perugia, Dipartimento di Fisica, P
erugia,
Italy
c
Now at Laboratoire de Physique Nucl ́eaire et de Hautes Energ
ies,
IN2P3/CNRS, Paris, France
d
Now at Forschungszentrum J ̈ulich GmbH, D-52425 J ̈ulich, Ge
r-
many
e
Now at the University of Huddersfield, Huddersfield HD1 3DH,
UK
f
Deceased
g
Now at University of South Alabama, Mobile, Alabama 36688,
USA
h
Also with Universit`a di Sassari, Sassari, Italy
i
Also with INFN Sezione di Roma, Roma, Italy
j
Now at Universidad T ́ecnica Federico Santa Maria, Valparai
so,
Chile 2390123
onance labeled the
X
(4140) decaying to
J/ψφ
[4]. They
found evidence in the same decay mode for another res-
onance, labeled as the
X
(4270) [5]. Recently, the LHCb
experiment studied the decay
B
+
J/ψφK
+
in
pp
colli-
sions at 7 TeV, with a data sample more than three times
larger than that of CDF, and set an upper limit (UL)
incompatible with the CDF result [6]. The D0 and the
CMS experiments more recently made studies of the same
decay channel, leading to different conclusions [7, 8] than
the LHCb experiment. In this work we study the rare
decays
B
+
J/ψK
+
K
K
+
,
B
0
J/ψK
+
K
K
0
S
and
search for possible resonant states in the
J/ψφ
mass spec-
trum. We also search for the decay
B
0
J/ψφ
, which
is expected to proceed mainly via a Cabibbo-suppressed
and color-suppressed transition
̄
bd
̄
cc
̄
dd
. The absence
of a signal would indicate that the required rescattering
of
̄
dd
into ̄
ss
is very small.
This paper is organized as follows. In Sec. II we de-
scribe the detector and data selection and in Sec. III we
report the branching-fraction (BF) measurements. Sec-
tion IV is devoted to the resonance search, while Sec. V
summarizes the results.
II. THE
B
A
B
AR
DETECTOR AND DATA
SELECTION
We make use of the data set collected by the
B
A
B
AR
detector at the PEP-II
e
+
e
storage rings operating at
6
the
Υ
(4
S
) resonance. The integrated luminosity for this
analysis is 422.5 fb
1
, which corresponds to the produc-
tion of 469 million
B
B
pairs [9].
The
B
A
B
AR
detector is described in detail else-
where [10]. We mention here only the components of the
detector that are used in the present analysis. Charged
particles are detected and their momenta measured with
a combination of a cylindrical drift chamber (DCH) and
a silicon vertex tracker (SVT), both operating within the
1.5 T magnetic field of a superconducting solenoid. Infor-
mation from a ring-imaging Cherenkov detector (DIRC)
is combined with specific ionization measurements from
the SVT and DCH to identify charged kaon and pion
candidates. The efficiency for kaon identification is 90%
while the rate for a pion being misidentified as a kaon
is 2%. For low transverse momentum kaon candidates
that do not reach the DIRC, particle identification re-
lies only on the energy loss measurement, so that the
transverse momentum spectrum of identified kaons ex-
tends down to 150 MeV/
c
. Electrons are identified us-
ing information provided by a CsI(Tl) electromagnetic
calorimeter (EMC), in combination with that from the
SVT and DCH, while muons are identified in the Instru-
mented Flux Return (IFR). This is the outermost subde-
tector, in which muon/pion discrimination is performed.
Photons are detected, and their energies measured with
the EMC.
For each signal event candidate, we first reconstruct
the
J/ψ
by geometrically constraining to a common ver-
tex a pair of oppositely charged tracks, identified as either
electrons or muons, and apply a loose requirement that
the
χ
2
fit probability exceed 0.1%. For
J/ψ
e
+
e
we
use bremsstrahlung energy-loss recovery: if an electron-
associated photon cluster is found in the EMC, its three-
momentum vector is incorporated into the calculation of
the invariant mass
m
e
+
e
. The vertex fit for a
J/ψ
can-
didate includes a constraint to the nominal
J/ψ
mass
value [11].
For
B
+
J/ψK
+
K
K
+
candidates, we combine the
J/ψ
candidate with three loosely identified kaons and re-
quire a vertex-fit probability larger than 0.1%. Similarly,
for
B
0
J/ψK
K
+
K
0
S
candidates, we combine the
J/ψ
and
K
0
S
with two loosely identified kaons and require a
vertex-fit probability larger than 0.1%.
A
K
0
S
candidate is formed by geometrically constrain-
ing a pair of oppositely charged tracks to a common
vertex, with
χ
2
fit probability larger than 0.1%. The
pion mass is assigned to the tracks without particle-
identification (PID) requirements. The three-momenta
of the two pions are then added and the
K
0
S
energy is
computed using the nominal
K
0
S
mass. We require the
K
0
S
flight length significance with respect to the
B
0
ver-
tex to be larger than 3
σ
.
We further select
B
meson candidates using the en-
ergy difference ∆
E
E
B
s/
2 in the center-of-mass
frame and the beam-energy-substituted mass defined as
m
ES
((
s/
2 +
~p
i
·
~p
B
)
/E
i
)
2
~p
2
B
, where (
E
i
,~p
i
) is
the initial state
e
+
e
four-momentum vector in the labo-
ratory frame and
s
is the center-of-mass energy. In the
above expressions
E
B
is the
B
meson candidate energy in
the center-of-mass frame, and
~p
B
is its laboratory frame
momentum.
When multiple candidates are present, the combina-
tion with the smallest ∆
E
is chosen. We find that, af-
ter requiring
m
ES
>
5
.
2 GeV/
c
2
, the fraction of events
having multiple candidates is 1.3% for
B
+
and 8.6% for
B
0
. From simulation, we find that 99.6% of the time we
choose the correct candidate.
The final selection requires
|
E
|
<
30 MeV and
|
E
|
<
25 MeV for
B
+
and
B
0
decays, respectively; the
additional selection criterion
m
ES
>
5
.
2 GeV/
c
2
is re-
quired for the calculation of the BFs, while
m
ES
>
5
.
27
GeV/
c
2
is applied to select the signal region for the anal-
ysis of the invariant mass systems.
III. BRANCHING FRACTIONS
Figure 1 shows the
m
ES
distributions for (a)
B
+
J/ψK
+
K
K
+
and (b)
B
0
J/ψK
K
+
K
0
S
can-
didates after having applied the ∆
E
selections described
in Sec. II, while the corresponding ∆
E
distributions are
shown in Fig. 1(c) and Fig. 1(d), respectively, for
m
ES
>
5
.
27 GeV/
c
2
. Figure 2 shows the
K
+
K
invariant
mass distribution in the region
m
K
+
K
<
1.1 GeV/
c
2
for
(a)
B
+
and (b)
B
0
candidates. A clean
φ
(1020) signal
is present in both mass spectra. The background contri-
butions, estimated from the ∆
E
sidebands in the range
40
<
|
E
|
<
70 MeV, are shown as shaded histograms
in Fig. 2(a) and Fig. 2(b) and are seen to be small. In the
following we have ignored the presence of possible addi-
tional S-wave contributions in the
φ
(1020) signal region.
We select the
φ
(1020) signal region to be in the mass
range [1.004
1.034] GeV/
c
2
. Figure 2 shows the
m
ES
distribution for (c)
B
+
J/ψφK
+
and (d)
B
0
J/ψφK
0
S
candidates, respectively, for events in the
φ
mass region, which satisfy the ∆
E
selection criteria. Fig-
ures 2(e) and 2(f) show the ∆
E
distribution for
m
ES
>
5
.
27 GeV/
c
2
, when requiring the
K
+
K
invariant
mass to be in the
φ
(1020) signal region. The distributions
of Fig. 2(c) and Fig. 2(e) contain 212 events in the
m
ES
and ∆
E
signal region, with an estimated background of
23 events. Similarly, those of Fig. 2(d) and Fig. 2(f) con-
tain 50 events, with an estimated background of 9 events.
We search for the decay
B
0
J/ψφ
by constraining
a fitted
J/ψ
and two loosely identified kaon candidates
to a common vertex. Possible backgrounds originating
from the decay
B
0
J/ψK
0
(892),
K
0
(892)
K
π
+
,
and from the channel
B
0
J/ψK
1
(1270),
K
1
(1270)
K
π
+
π
0
are found consistent with zero, after applying
a dedicated selection as described in Sec. II and Sec. III.
Figure 3 shows the corresponding
m
ES
and ∆
E
distri-
butions. We do not observe a significant signal for this
decay mode.
For Figs. 1-3 an unbinned maximum likelihood fit to
each
m
ES
distribution is performed to determine the yield
7
)
2
(GeV/c
ES
m
5.2
5.21
5.22
5.23 5.24
5.25
5.26
5.27
5.28
5.29
2
Events / 2 MeV/c
0
20
40
60
80
100
120
(a)
)
2
(GeV/c
ES
m
5.2
5.21
5.22
5.23 5.24
5.25
5.26
5.27
5.28
5.29
2
Events / 2 MeV/c
0
10
20
30
40
50
60
70
(b)
E (GeV)
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Events / 5 MeV
0
10
20
30
40
50
60
70
80
90
(c)
E (GeV)
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Events / 5 MeV
0
10
20
30
40
50
(d)
FIG. 1: The
m
ES
distributions for (a)
B
+
J/ψK
+
K
K
+
and (b)
B
0
J/ψK
K
+
K
0
S
, for the ∆
E
regions indicated in the
text. The ∆
E
distributions for
m
ES
>
5
.
27 GeV/
c
2
are shown for (c)
B
+
J/ψK
+
K
K
+
and (d)
B
0
J/ψK
K
+
K
0
S
. The
continuous (red) curve represents the signal plus backgrou
nd, while the dotted (blue) curve represents the fitted backg
round.
Vertical (blue) lines indicate the selected signal regions
.
TABLE I: Event yields, efficiencies (
ǫ
) and BF measurements (
B
) for the different decay modes. For channels involving
K
0
S
, the
yields and efficiencies refer to
K
0
S
π
+
π
, the BF includes the corrections for
K
0
S
π
0
π
0
and
K
0
L
decay. The
B
0
J/ψφ
UL at 90% c.l. is listed at the end of the table.
B
channel
Event
ǫ
(%)
Corrected
B
(
×
10
5
)
yield
yield
B
+
J/ψK
+
K
K
+
290
±
22 15.08
±
0.04 1923
±
146 3.37
±
0.25
±
0.14
B
+
J/ψφK
+
189
±
14 13.54
±
0.04 1396
±
103 5.00
±
0.37
±
0.15
B
0
J/ψK
+
K
K
0
68
±
13 10.35
±
0.04 657
±
126 3.49
±
0.67
±
0.15
B
0
J/ψφK
0
41
±
7 10.10
±
0.04 406
±
69 4.43
±
0.76
±
0.19
B
0
J/ψφ
6
±
4 31.12
±
0.07
19
±
13
<
0
.
101
TABLE II: Systematic uncertainty contributions (%) to the e
valuation of the BFs.
Source
B
+
J/ψK
+
K
K
+
B
+
J/ψφK
+
B
0
J/ψK
K
+
K
0
S
B
0
J/ψφK
0
S
B
0
J/ψφ
B
B
counting
0.6
0.6
0.6
0.6
0.6
Efficiency
0.04
0.04
0.04
0.04
0.07
Tracking
0.9
0.9
1.2
1.2
0.7
K
0
S
1.7
1.7
Secondary BFs
0.08
0.5
0.1
0.5
0.5
Decay model
0.4
0.9
1.0
pdfs
3.0
0.7
2.0
0.5
1.0
PID
2.5
2.5
3.0
3.0
2.0
Total contribution
4.1
3.0
4.2
4.4
2.7
and obtain a BF measurement [12]. We use the sum
of two functions to parametrize the
m
ES
distribution; a
Gaussian function describes the signal, and an ARGUS
function [13] the background. A study of the ∆
E
side-
bands did not show the presence of peaking backgrounds.
Table I summarizes the fitted yields obtained.
As a validation test, we fit the ∆
E
distributions shown
in Figs. 1-3, using a double-Gaussian model for the signal
8
)
2
(GeV/c
-
K
+
K
m
0.98
1
1.02
1.04
1.06
1.08
1.1
2
Events / 2 MeV/c
0
10
20
30
40
50
60
70
(a)
)
2
(GeV/c
-
K
+
K
m
0.98
1
1.02
1.04
1.06
1.08
1.1
2
Events / 2 MeV/c
0
2
4
6
8
10
12
14
16
18
20
(b)
)
2
(GeV/c
ES
m
5.2
5.21
5.22
5.23 5.24
5.25
5.26
5.27
5.28
5.29
2
Events / 2 MeV/c
0
10
20
30
40
50
60
70
(c)
)
2
(GeV/c
ES
m
5.2
5.21
5.22
5.23 5.24
5.25
5.26
5.27
5.28
5.29
2
Events / 2 MeV/c
0
2
4
6
8
10
12
14
16
18
20
(d)
E (GeV)
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Events / 5 MeV
0
10
20
30
40
50
60
70
(e)
E (GeV)
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Events / 5 MeV
0
2
4
6
8
10
12
14
16
18
20
(f)
FIG. 2: (a) The
K
+
K
mass spectrum, (c)
m
ES
, and (e) ∆
E
distribution for
B
+
J/ψφK
+
. (b) The
K
+
K
mass spectrum,
(d)
m
ES
, and (f) ∆
E
distribution for
B
0
J/ψφK
0
S
. The dots are the data points, the shaded (yellow) distribut
ions are
obtained from the ∆
E
sidebands. Vertical (blue) lines indicate the selected sig
nal regions. In (a) and (b) the
m
ES
and ∆
E
selection criteria described in Sec. II have been applied.
)
2
(GeV/c
ES
m
5.2
5.21
5.22
5.23 5.24
5.25
5.26
5.27
5.28
5.29
2
Events / 2 MeV/c
0
1
2
3
4
5
6
7
8
9
10
(a)
E (GeV)
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
Events / 5 MeV
0
1
2
3
4
5
6
7
8
9
10
(b)
FIG. 3: (a) The
m
ES
and (b) ∆
E
distribution for
B
0
J/ψφ
event candidates. The curves in (a) and (b) are the result of
the fits described in the text.
and a linear function for the background, and we obtain
yields consistent with those from the
m
ES
fits.
The signals in Fig. 1, corresponding to the
B
+
J/ψK
+
K
K
+
and the
B
0
J/ψK
+
K
K
0
S
decays,
yield 14.4
σ
and 5.5
σ
significance, respectively. Those in
Fig. 2, which restrict the invariant mass
m
K
+
K
to the
signal region of the
φ
(1020) meson, are observed with
significance 16.1
σ
and 5.6
σ
, respectively. In this pa-
per the statistical significance of the peaks is evaluated
as
2
ln
(
L
0
/L
max
), where
L
max
and
L
0
represent the
maximum likelihood values with the fitted signal yield
and with the signal yield fixed to zero, respectively.
We estimate the efficiency for the different channels us-
ing Monte Carlo (MC) simulations. For each channel we
perform full detector simulations where
B
mesons decay
uniformly over the available phase space (PHSP). These
9
)
4
/c
2
(GeV
2
+
K
φ
m
2.5
3
3.5
4
4.5
5
)
4
/c
2
(GeV
2
φψ
J/
m
17
18
19
20
21
22
23
0
0.05
0.1
0.15
0.2
0.25
(a)
)
4
/c
2
(GeV
2
+
K
φ
m
2.5
3
3.5
4
4.5
5
)
4
/c
2
(GeV
2
φψ
J/
m
17
18
19
20
21
22
23
0
0.05
0.1
0.15
0.2
0.25
(b)
FIG. 4: Efficiency distribution on the Dalitz plot for (a)
B
+
J/ψφK
+
and (b)
B
0
J/ψφK
0
S
.
)
2
(GeV/c
-
K
+
K
ψ
J/
m
4.2
4.3
4.4
4.5
4.6
4.7
2
Combinations / 10 MeV/c
0
5
10
15
20
25
30
(a)
)
2
(GeV/c
-
K
+
K
ψ
J/
m
4.2
4.3
4.4
4.5
4.6
4.7
2
Combinations / 10 MeV/c
0
2
4
6
8
10
12
14
16
(b)
FIG. 5: Invariant mass distribution
J/ψK
+
K
for (a)
B
+
J/ψK
+
K
K
+
and (b)
B
0
J/ψK
+
K
K
0
S
. The shaded
(yellow) histogram on each figure indicates the background e
stimated from the ∆
E
sidebands.
simulated events are then reconstructed and analyzed as
are the real data. These MC simulations are also used to
validate the analysis procedure and the BF extractions.
Table I reports the resulting integrated efficiencies for
the different channels, and the efficiency-corrected yields.
The efficiency is computed in two different ways. For
B
+
J/ψφK
+
and
B
0
J/ψφK
0
S
we make use of
a Dalitz-plot-dependent efficiency, where each event is
weighted by the inverse of the efficiency evaluated in the
appropriate cell of the Dalitz plot shown in Fig. 4. This
approach is particularly important because of the lower
efficiency observed at low
J/ψφ
invariant mass, where
the spectrum deviates from pure PHSP behavior. For
the
φ
channels, the “Corrected yield” values in Table
I are obtained as sums of inverse Dalitz-plot efficien-
cies for events in the
φ
signal regions with background-
subtraction taken into account as described in Sec. IV.
The events in the
φ
signal region account for about 65%
of the data in the four-body final states. There is no evi-
dence of structure in the remaining
35% of these events,
and so they are corrected according to their average effi-
ciency obtained from MC simulation of four-body PHSP
samples. For these channels,
B
+
J/ψK
+
K
K
+
and
B
0
J/ψK
+
K
K
0
S
, the PHSP corrected yield is added
to the
φ
signal region corrected yield to obtain the “Cor-
rected yield” values in lines 1 and 3 of Table I. The effi-
ciency values in the third column of Table I correspond
to “Event yield” divided by “Corrected yield”.
Systematic uncertainties affecting the BF measure-
ments are listed in Table II. The evaluation of the in-
tegrated luminosity is performed using the method of
B
B
counting [10], and we assign a uniform 0.6% un-
certainty to all the final states. The uncertainty on
the efficiency evaluation related to the size of the MC
simulations is negligible with respect to the other con-
tributions. The systematic uncertainty on the recon-
struction efficiency of charged-particle tracks is estimated
from the comparison of data samples and full detector
simulations for well-chosen decay modes. In a similar
way we obtain a 1.7% systematic uncertainty in the re-
construction of
K
0
S
meson decays. In the case of the
B
0
J/ψφK
0
S
and
B
+
J/ψφK
+
decay modes, since
the
J/ψ
and the
φ
are vector states, we compute the
efficiency also under the assumption that the two vec-
tor mesons are transversely or longitudinally polarized.
We consider the uncertainties related to the choice of
the probability density functions (pdf) in the fit proce-
dure, by varying fixed parameters by
±
1
σ
in their un-
certainties. We also evaluate the efficiency variations
for different charged-particle-track PID. All uncertain-
ties are added in quadrature. We note that the BF for
B
+
J/ψφK
+
and that for
B
0
J/ψφK
0
are in
agreement with their previous
B
A
B
AR
measurements [14],
which already dominate the PDG average values [11], but
now we obtain more than four times better precision. The
combination of these decay modes was observed first by
the CLEO Collaboration [15]. Our BF value for the decay
B
+
J/ψK
+
K
K
+
is the first measurement. For the
10
decay
B
0
J/ψK
+
K
K
0
, the LHCb Collaboration has
obtained a BF value (2
.
02
±
0
.
43
±
0
.
17
±
0
.
08)
×
10
5
[16],
which is consistent with our result.
We estimate an upper limit (UL) at 90% confidence
level (c.l.) for the BF of the decay
B
0
J/ψφ
. The
signal yield obtained from the fit to the
m
ES
distribu-
tion is 6
±
4 events (Fig. 3(a)), corresponding to an UL at
90% c.l. of 14 events. The Feldman-Cousins method [17]
is used to evaluate ULs on BFs. Ensembles of pseudo-
experiments are generated according to the pdfs for a
given signal yield (10000 sets of signal and background
events), and fits are performed. We obtain an UL on
the
B
0
J/ψφ
BF of 1.01
×
10
6
. The Belle Collabora-
tion reported a limit of 0
.
94
×
10
6
[18], while a recent
analysis from the LHCb Collaboration lowers this limit
to 1
.
9
×
10
7
[19].
We compute the ratios
R
+
=
B
(
B
+
J/ψK
+
K
K
+
)
B
(
B
+
J/ψφK
+
)
= 0
.
67
±
0
.
07
±
0
.
03 (1)
and
R
0
=
B
(
B
0
J/ψK
+
K
K
0
)
B
(
B
0
J/ψφK
0
)
= 0
.
79
±
0
.
20
±
0
.
05
,
(2)
and they are consistent with being equal within the un-
certainties. We also compute the ratios
R
φ
=
B
(
B
0
J/ψφK
0
)
B
(
B
+
J/ψφK
+
)
= 0
.
89
±
0
.
17
±
0
.
04 (3)
and
R
2
K
=
B
(
B
0
J/ψK
+
K
K
0
)
B
(
B
+
J/ψK
+
K
K
+
)
= 1
.
04
±
0
.
21
±
0
.
06
.
(4)
On the basis of the simplest relevant color-suppressed
spectator quark model diagrams (e.g. Fig.1 of Ref. [15]),
it would be expected that
R
+
=
R
0
and
R
φ
R
2
K
1.
Our measured values of these ratios are consistent with
these expectations.
IV. SEARCH FOR RESONANCE PRODUCTION
We plot in Fig. 5(a) the
J/ψK
+
K
mass distribution
for
B
+
J/ψK
+
K
K
+
and in Fig. 5(b) that for
B
0
J/ψK
K
+
K
0
S
; the signal regions are defined by the ∆
E
selections indicated in Sec. II and
m
ES
>
5
.
27 GeV/
c
2
.
No prominent structure is observed in both mass spectra.
We select events in the
φ
signal regions and search for
the resonant states reported by the CDF Collaboration
in the
J/ψφ
mass spectrum [5]. The mass and the width
values are fixed to
m
=4143.4 MeV/
c
2
and Γ=15.3 MeV
for the
X
(4140), and
m
=4274.4 MeV/
c
2
and Γ= 32.3
MeV for the
X
(4270) resonance. We evaluate the mass
resolution using MC simulations and obtain 2 MeV/
c
2
resolution in the mass region between 4100 MeV/
c
2
and
4300 MeV/
c
2
. Therefore resolution effects can be ignored
because they are much smaller than the widths of the
resonances under consideration.
We estimate the efficiency on each quasi-three-body
Dalitz plot as the ratio between the reconstructed and
generated distributions, where the values are generated
according to PHSP. Figure 4 shows the resulting dis-
tributions evaluated over the
m
2
J/ψφ
vs m
2
φK
plane for
the charged (a) and neutral (b)
B
decay, respectively.
The lower efficiency at low
J/ψφ
mass is due to the
lower reconstruction efficiency for low kaon momentum
in the laboratory frame, as a result of energy loss in the
beampipe and SVT material.
We test the agreement between data and MC by us-
ing a full MC simulation where the
B
+
J/ψφK
+
and
B
0
J/ψφK
0
S
decays are included with known branch-
ing fractions. We repeat the entire analysis on these sim-
ulated data and find good agreement between generated
and reconstructed branching fractions. Resolution effects
are small and are computed using MC simulations. We
obtain average values of 2.9 MeV for (
J/ψφ
) and 2.2 MeV
for (
J/ψK
). These small values do not produce bias in
the evaluation of the efficiency and the measurement of
the branching fractions.
To search for the two resonances in the
J/ψφ
mass dis-
tributions, we perform unbinned maximum likelihood fits
to the
B
J/ψφK
decay Dalitz plots. We model the
resonances using S-wave relativistic Breit-Wigner (BW)
functions with parameters fixed to the CDF values. The
non-resonant contributions are represented by a constant
term, and no interference is allowed between the fit com-
ponents. We estimate the background contributions from
the ∆
E
sidebands, find them to be small and consistent
with a PHSP behavior, and so in the fits they are incorpo-
rated into the non-resonant PHSP term. The decay of a
pseudoscalar meson to two vector states may contain high
spin contributions which could generate non-uniform an-
gular distributions. However, due to the limited data
sample we do not include such angular terms, and assume
that the resonances decay isotropically. The amplitudes
are normalized using PHSP MC generated events with
B
parameters obtained from the fits to the data. The fit
functions are weighted by the the two-dimensional effi-
ciency computed on the Dalitz plots.
We perform fits separately for the charged
B
+
sample
and the combined
B
+
and
B
0
samples. Due to the very
limited statistics of the
B
0
sample we do not perform a
separate fit, but instead subtract the fit result for the
B
+
sample from that for the combined
B
+
and
B
0
sample.
In this case we make use of the two different efficiencies
for the two channels. In the MC simulation performed,
we make use of a weighted mean of the two efficiencies
evaluated on the respective Dalitz plots.
Table III summarizes the results of the fits. We report
the background-corrected fit fractions for the two reso-
nances,
f
X
(4140)
and
f
X
(4270)
, the two-dimensional (2D)
χ
2
computed on the Dalitz plot, and the one-dimensional
(1D)
χ
2
computed on the
J/ψφ
mass projection. For
this purpose, we use an adaptive binning method, and
11
TABLE III: Results of the fits to the
B
J/ψφK
Dalitz plots. For each fit, the table gives the fit fraction for
each resonance,
and the 2D and 1D
χ
2
values. The fractions are corrected for the background comp
onent.
Channel Fit
f
X
(4140)
(%)
f
X
(4270)
(%) 2D
χ
2
1D
χ
2
B
+
A 9.2
±
3.3 10.6
±
4.8 12.7/12 6.5/20
B 9.2
±
2.9
0.
17.4/13 15.0/17
C
0.
10.0
±
4.8 20.7/13 19.3/19
D
0.
0.
26.4/14 34.2/18
B
0
+
B
+
A 7.3
±
3.8 12.0
±
4.9 8.5/12 15.9/19
2
)
2
(GeV/c
2
φψ
J/
m
17
18
19
20
21
22
23
2
)
2
Events / 0.16 (GeV/c
0
5
10
15
20
25
(a)
2
)
2
(GeV/c
2
+
K
φ
m
2.5
3
3.5
4
4.5
5
2
)
2
Events / 0.07 (GeV/c
0
5
10
15
20
25
(b)
2
)
2
(GeV/c
2
+
K
ψ
J/
m
13
14
15
16
17
18
2
)
2
Events / 0.15 (GeV/c
0
5
10
15
20
25
(c)
FIG. 6: Dalitz plot projections for
B
+
J/ψφK
+
on (a)
m
2
J/ψφ
, (b)
m
2
φK
+
, and (c)
m
2
J/ψK
+
. The continuous (red) curves
are the results from fit model A performed including the
X
(4140) and
X
(4270) resonances. The dashed (blue) curve in (a)
indicates the projection for fit model D, with no resonances.
The shaded (yellow) histograms indicate the background est
imated
from the ∆
E
sidebands.
divide the Dalitz plot into a number of cells in such
a way that the minimum expected population per cell
is not smaller than 7. We generate MC simulations
weighted by the efficiency and by the results from the
fits. These are normalized to the event yield in data,
using the same bin definitions. We then compute the
χ
2
=
N
cells
i
=1
(
N
i
obs
N
i
exp
)
2
/N
i
exp
where
N
i
obs
and
N
i
exp
are the data and MC simulation event yields, respec-
tively. Indicating with
n
the number of free parameters,
corresponding to the number of resonances included in
the fit, the number of degrees of freedom is
ν
=
N
cells
n
.
In computing the 1D
χ
2
we rebin the
J/ψφ
mass projec-
tion into 25 bins, again with at least 7 entries per bin.
We perform the fits using models with two resonances
(labeled as model A), one resonance (models B and C),
and no resonances (model D). The fit projections for fit
A are displayed in Fig. 6, showing enhancements with a
statistical significance smaller than 3.2
σ
for all fit models.
All models provide a reasonably good description of the
data, with
χ
2
probability larger than 1%.
We estimate systematic uncertainties on the fractions
by varying the mass and the width values for both reso-
nances within their uncertainties. The results shown in
Table III are corrected by the fraction of background es-
timated in each sample. This results in correction factors
of 1.12 and 1.21 for the
B
+
and the
B
0
channels, respec-
tively. We obtain the following background-corrected
fractions for
B
+
:
f
X
(4140)
= (9
.
2
±
3
.
3
±
4
.
7)%
, f
X
(4270)
= (10
.
6
±
4
.
8
±
7
.
1)%
.
(5)
Combining statistical and systematic uncertainties in
quadrature, we obtain significances of 1.6 and 1.2
σ
for
the
X
(4140) and the
X
(4270), respectively.
Using the Feldman-Cousins method [17], we obtain the
ULs at 90% c.l.:
B
(
B
+
X
(4140)
K
+
)
× B
(
X
(4140)
J/ψφ
)
/
B
(
B
+
J/ψφK
+
)
<
0
.
133 (6)
B
(
B
+
X
(4270)
K
+
)
× B
(
X
(4270)
J/ψφ
)
/
B
(
B
+
J/ψφK
+
)
<
0
.
181
.
(7)
The Feldman-Cousin intervals are evaluated as explained
in Ref. [17] and in Sec. III. The
X
(4140) limit may be
compared with the CDF measurement of 0
.
149
±
0
.
039
±
0
.
024 [4] and the LHCb limit of 0.07 [6]. The
X
(4270)
limit may be compared with the LHCb limit of 0.08.
The fit projections on the
J/ψφ
mass spectrum using
fit model A with two resonances are shown in Fig. 7(a) for
B
+
, in Fig. 7(b) for
B
0
, and in Fig. 7(c) for the combined
B
+
and
B
0
sample. The fit results are summarized in
Table III.
The central values of mass and width of the two reso-
nances are also fixed to the values recently published by
the CMS Collaboration [8]. In this case we obtain, for the
B
+
data, the following background-corrected fractions:
f
X
(4140)
= (13
.
2
±
3
.
8
±
6
.
8)%
, f
X
(4270)
= (10
.
9
±
5
.
2
±
7
.
3)%
.
(8)
12
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Events / 20 MeV/c
0
5
10
15
20
25
(a)
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Events / 20 MeV/c
0
1
2
3
4
5
6
7
8
9
10
(b)
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Events / 20 MeV/c
0
5
10
15
20
25
(c)
FIG. 7: Projections on the
J/ψφ
mass spectrum from the Dalitz plot fit with the
X
(4140) and the
X
(4270) resonances for the
(a)
B
+
, (b)
B
0
, and (c) combined
B
+
and
B
0
data samples. The continuous (red) curves result from the fit
; the dashed (blue)
curve in (a) indicates the projection for fit model D, with no r
esonances. The shaded (yellow) histograms show the backgro
und
contributions estimated from the ∆
E
sidebands.
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Efficiency / 20 MeV/c
0
0.05
0.1
0.15
0.2
0.25
(a)
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Events / 20 MeV/c
0
50
100
150
200
250
(b)
)
2
(GeV/c
φψ
J/
m
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
2
Events / 20 MeV/c
0
50
100
150
200
250
(c)
FIG. 8: (a) Average efficiency distribution as a function of
J/ψφ
invariant mass for
B
+
J/ψφK
+
. (b) Efficiency-corrected
J/ψφ
mass spectrum for the combined
B
+
and
B
0
samples. The curve is the result from fit model A described in t
he
text. The shaded (yellow) histogram represents the efficienc
y-corrected background contribution. (c) Efficiency-corre
cted and
background-subtracted
J/ψφ
mass spectrum for the combined
B
+
and
B
0
samples.
These values are consistent within the uncertainties with
those obtained in Eq. (5). For comparison, CMS reported
a fraction of 0
.
10
±
0
.
03 for the X(4140), which is compat-
ible with the CDF, the LHCb and our value within the
uncertainties; CMS could not determine reliably the sig-
nificance of the second structure X(4270) due to possible
reflections of two-body decays.
Figure 8(a) shows the efficiency as a function of the
J/ψφ
mass, obtained from a PHSP simulation of the
B
+
J/ψφK
+
Dalitz plot. We observe a decrease of
the efficiency in the
J/ψφ
threshold region, as already
observed in Fig. 4.
Figure 8(b) shows the efficiency-corrected
J/ψφ
mass
spectrum for the combined
B
+
and
B
0
samples. To ob-
tain this spectrum, we weight each event by the inverse
of the efficiency evaluated on the respective
B
+
and
B
0
Dalitz plots. The curve is the result from fit model
A. The background contribution (shown shaded) is es-
timated from the ∆
E
sidebands, and has also been cor-
rected for efficiency. However, a few background events
fall outside the efficiency Dalitz plots, and to these we
assign the same efficiency as for
B
signal events.
Finally, Fig. 8(c) shows the efficiency-corrected and
background-subtracted
J/ψφ
mass spectrum for the com-
bined
B
+
and
B
0
samples.
V. SUMMARY
In summary, we perform a study of the decays
B
+
,
0
J/ψK
+
K
K
+
,
0
and
B
+
,
0
J/ψφK
+
,
0
, and
for the latter obtain much-improved BF measurements.
For
B
+
J/ψK
+
K
K
+
this is the first measurement.
We search for resonance production in the
J/ψφ
mass
spectrum and obtain significances below 2
σ
for both the
X
(4140) and the
X
(4270) resonances, with systematic
uncertainties taken into account. Limits on the prod-
uct Branching Ratio values for these resonances are ob-
tained. We find that the hypothesis that the events are
distributed uniformly on the Dalitz plot gives a poorer
description of the data. We also search for
B
0
J/ψφ
and derive an UL on the BF for this decay mode, which
is in agreement with theoretical expectations.
VI. ACKNOWLEDGEMENTS
We are grateful for the extraordinary contributions
of our PEP-II colleagues in achieving the excellent lu-
minosity and machine conditions that have made this
work possible. The success of this project also re-
lies critically on the expertise and dedication of the
13
computing organizations that support
B
A
B
AR
. The
collaborating institutions wish to thank SLAC for its
support and the kind hospitality extended to them.
This work is supported by the US Department of En-
ergy and National Science Foundation, the Natural Sci-
ences and Engineering Research Council (Canada), the
Commissariat `a l’Energie Atomique and Institut Na-
tional de Physique Nucl ́eaire et de Physique des Partic-
ules (France), the Bundesministerium f ̈ur Bildung und
Forschung and Deutsche Forschungsgemeinschaft (Ger-
many), the Istituto Nazionale di Fisica Nucleare (Italy),
the Foundation for Fundamental Research on Matter
(The Netherlands), the Research Council of Norway, the
Ministry of Education and Science of the Russian Federa-
tion, Ministerio de Ciencia e Innovaci ́on (Spain), and the
Science and Technology Facilities Council (United King-
dom). Individuals have received support from the Marie-
Curie IEF program (European Union), the A. P. Sloan
Foundation (USA) and the Binational Science Founda-
tion (USA-Israel).
[1] N. Brambilla
et al.
, Quarkonium Working Group Collab-
oration,
Yellow Report
, arXiv:0412158v2 [hep-ph](2005).
[2] N. Brambilla
et al.
, Eur. Phys. J. C
71
, 1534 (2011).
[3] The use of charge conjugate reactions is implied through
-
out this work.
[4] T. Aaltonen
et al.
(CDF Collaboration), Phys. Rev. Lett.
102
, 242002 (2009).
[5] T. Aaltonen
et al.
(CDF Collaboration), arXiv:1101.6058
[hep-ex].
[6] R. Aaij
et al.
(LHCb Collaboration), Phys. Rev. D
85
,
091103(R) (2012).
[7] V.M. Abazov
et al.
(D0 Collaboration), Phys. Rev. D
89
,
012004 (2014).
[8] S. Chatrchyan
et al.
(CMS Collaboration), Phy. Lett. B
734
, 261 (2014).
[9] J. P. Lees
et al.
(
B
A
B
AR
Collaboration), Nucl. Instrum.
Meth. Phys. Res., Sect. A
726
, 203 (2013).
[10] B. Aubert
et al.
(
B
A
B
AR
Collaboration), Nucl. Instrum.
Meth. Phys. Res., Sect. A
479
, 1 (2002);
ibid.
729
, 615
(2013).
[11] J. Beringer
et al.
(PDG Collaboration), Phys. Rev. D
86
,
010001 (2012).
[12] The BFs are calculated by dividing the efficiency-
corrected yields in Table I by the product of
N
B
̄
B
×
Π
i
BFS
i
, where BFS
i
= BF of particles involved
in the relevant
Υ
(4
S
) decay and in the corresponding
B
meson decay processes.
[13] H. Albrecht
et al.
(ARGUS Collaboration), Z. Phys. C
48
, 543 (1990).
[14] B. Aubert
et al.
(
B
A
B
AR
Collaboration), Phys. Rev.
Lett.
91
, 071801 (2003).
[15] A.Anastassov et al. (CLEO Collaboration), Phys. Rev.
Lett.
84
, 1393 (2000).
[16] R. Aaij et al. (LHCb Collaboration), JHEP
07
, 140
(2014).
[17] G. J. Feldman and R. D. Cousins, Phys. Rev. D.
57
,
3873 (1998).
[18] Y. Liu
et al.
(Belle Collaboration), Phys. Rev. D
78
,
011106 (2008).
[19] R. Aaij
et al.
(LHCb Collaboration), Phys. Rev. D
88
,
072005 (2013).