Search for a Charged Partner of the X(3872) in the B Meson Decay B -- X- K, X- -- Jpsi pi-
a r X i v :h e p -e x /0412051v 1 18 D e c 2004
B A B A R -PUB-04/043SLAC-PUB-10903
Search for a Charged Partner of the X (3872)in the B Meson Decay B →X ?K ,X ?→J/ψπ?π0
B.Aubert,1R.Barate,1D.Boutigny,1F.Couderc,1Y.Karyotakis,1J.P.Lees,1V.Poireau,1V.Tisserand,1A.Zghiche,1E.Grauges-Pous,2A.Palano,3A.Pompili,3J.
C.Chen,4N.
D.Qi,4G.Rong,4P.Wang,4Y.S.Zhu,4G.Eigen,5I.Ofte,5B.Stugu,5G.S.Abrams,6A.W.Borgland,6A.B.Breon,6D.N.Brown,6J.Button-Shafer,6R.N.Cahn,6
E.Charles,6C.T.Day,6M.S.Gill,6A.V.Gritsan,6Y.Groysman,6R.G.Jacobsen,6R.W.Kadel,6
J.Kadyk,6L.T.Kerth,6Yu.G.Kolomensky,6G.Kukartsev,6G.Lynch,6L.M.Mir,6P.J.Oddone,6T.J.Orimoto,6M.Pripstein,6N.A.Roe,6M.T.Ronan,6W.A.Wenzel,6M.Barrett,7K.E.Ford,7T.J.Harrison,7A.J.Hart,7C.M.Hawkes,7S.E.Morgan,7A.T.Watson,7M.Fritsch,8K.Goetzen,8T.Held,8H.Koch,8B.Lewandowski,8M.Pelizaeus,8T.Schroeder,8M.Steinke,8J.T.Boyd,9N.Chevalier,9W.N.Cottingham,9M.P.Kelly,https://www.sodocs.net/doc/bd15544408.html,tham,9F.F.Wilson,9T.Cuhadar-Donszelmann,10C.Hearty,10N.S.Knecht,10T.S.Mattison,10J.A.McKenna,10D.Thiessen,10A.Khan,11P.Kyberd,11L.Teodorescu,11A.E.Blinov,12V.E.Blinov,12V.P.Druzhinin,12V.B.Golubev,12V.N.Ivanchenko,12E.A.Kravchenko,12A.P.Onuchin,12S.I.Serednyakov,12Yu.I.Skovpen,12E.P.Solodov,12A.N.Yushkov,12D.Best,13M.Bruinsma,13
M.Chao,13I.Eschrich,13D.Kirkby,https://www.sodocs.net/doc/bd15544408.html,nkford,13M.Mandelkern,13R.K.Mommsen,13W.Roethel,13D.P.Stoker,13C.Buchanan,14B.L.Hart?el,14A.J.R.Weinstein,14S.D.Foulkes,15J.W.Gary,15O.Long,15
B.C.Shen,15K.Wang,15D.del Re,16H.K.Hadavand,16E.J.Hill,16D.B.MacFarlane,16H.P.Paar,16
Sh.Rahatlou,16V.Sharma,16J.Adam Cunha,17J.W.Berryhill,17C.Campagnari,17B.Dahmes,17T.M.Hong,17
A.Lu,17M.A.Mazur,17J.D.Richman,17W.Verkerke,17T.W.Beck,18A.M.Eisner,18C.A.Heusch,18J.Kroseberg,18W.S.Lockman,18G.Nesom,18T.Schalk,18
B.A.Schumm,18A.Seiden,18P.Spradlin,18
D.C.Williams,18M.G.Wilson,18J.Albert,19
E.Chen,19G.P.Dubois-Felsmann,19A.Dvoretskii,19D.G.Hitlin,19
I.Narsky,19T.Piatenko,19F.C.Porter,19A.Ryd,19A.Samuel,19S.Yang,19S.Jayatilleke,20G.Mancinelli,20B.T.Meadows,20M.D.Sokolo?,20F.Blanc,21P.Bloom,21S.Chen,21W.T.Ford,21U.Nauenberg,21A.Olivas,21P.Rankin,21W.O.Ruddick,21J.G.Smith,21K.A.Ulmer,21J.Zhang,21L.Zhang,21A.Chen,22E.A.Eckhart,22J.L.Harton,22A.So?er,22W.H.Toki,22R.J.Wilson,22F.Winklmeier,22Q.Zeng,22B.Spaan,23D.Altenburg,24
T.Brandt,24J.Brose,24M.Dickopp,24E.Feltresi,24A.Hauke,https://www.sodocs.net/doc/bd15544408.html,cker,24R.Nogowski,24
S.Otto,24A.Petzold,24J.Schubert,24K.R.Schubert,24R.Schwierz,24J.E.Sundermann,24D.Bernard,25G.R.Bonneaud,25P.Grenier,25S.Schrenk,25Ch.Thiebaux,25G.Vasileiadis,25M.Verderi,25D.J.Bard,26P.J.Clark,26F.Muheim,26S.Playfer,26Y.Xie,26M.Andreotti,27V.Azzolini,27D.Bettoni,27C.Bozzi,27R.Calabrese,27G.Cibinetto,27E.Luppi,27M.Negrini,27L.Piemontese,27A.Sarti,27E.Treadwell,28F.Anulli,29R.Baldini-Ferroli,29A.Calcaterra,29R.de Sangro,29G.Finocchiaro,29P.Patteri,29I.M.Peruzzi,29M.Piccolo,29
A.Zallo,29A.Buzzo,30R.Capra,30R.Contri,30G.Crosetti,30M.Lo Vetere,30M.Macri,30M.R.Monge,30
S.Passaggio,30C.Patrignani,30E.Robutti,30A.Santroni,30S.Tosi,30S.Bailey,31G.Brandenburg,31
K.S.Chaisanguanthum,31M.Morii,31E.Won,31R.S.Dubitzky,https://www.sodocs.net/doc/bd15544408.html,ngenegger,32J.Marks,32U.Uwer,32W.Bhimji,33D.A.Bowerman,33P.D.Dauncey,33U.Egede,33J.R.Gaillard,33G.W.Morton,33J.A.Nash,33M.B.Nikolich,33G.P.Taylor,33M.J.Charles,34G.J.Grenier,34U.Mallik,34J.Cochran,35H.B.Crawley,https://www.sodocs.net/doc/bd15544408.html,msa,35W.T.Meyer,35S.Prell,35E.I.Rosenberg,35A.E.Rubin,35J.Yi,35M.Biasini,36R.Covarelli,36M.Pioppi,36N.Arnaud,37M.Davier,37X.Giroux,37G.Grosdidier,37A.H¨o cker,37F.Le Diberder,37V.Lepeltier,37A.M.Lutz,37T.C.Petersen,37S.Plaszczynski,37M.H.Schune,37G.Wormser,37C.H.Cheng,https://www.sodocs.net/doc/bd15544408.html,nge,38M.C.Simani,38D.M.Wright,38A.J.Bevan,39C.A.Chavez,39J.P.Coleman,39I.J.Forster,39J.R.Fry,39E.Gabathuler,39R.Gamet,39D.E.Hutchcroft,39R.J.Parry,39D.J.Payne,39C.Touramanis,39C.M.Cormack,40F.Di Lodovico,40C.L.Brown,41G.Cowan,41R.L.Flack,41H.U.Flaecher,41M.G.Green,41P.S.Jackson,41T.R.McMahon,41S.Ricciardi,41F.Salvatore,41M.A.Winter,41D.Brown,42C.L.Davis,42J.Allison,43N.R.Barlow,43R.J.Barlow,43M.C.Hodgkinson,https://www.sodocs.net/doc/bd15544408.html,?erty,43J.C.Williams,43C.Chen,44A.Farbin,44W.D.Hulsbergen,44A.Jawahery,44D.Kovalskyi,https://www.sodocs.net/doc/bd15544408.html,e,44V.Lillard,44D.A.Roberts,44G.Blaylock,45C.Dallapiccola,45S.S.Hertzbach,45R.Ko?er,45V.B.Koptchev,45T.B.Moore,45S.Saremi,45H.Staengle,45S.Willocq,45R.Cowan,46K.Koeneke,46G.Sciolla,46S.J.Sekula,46F.Taylor,46R.K.Yamamoto,46P.M.Patel,47
S.H.Robertson,https://www.sodocs.net/doc/bd15544408.html,zzaro,48V.Lombardo,48F.Palombo,48J.M.Bauer,49L.Cremaldi,49V.Eschenburg,49 R.Godang,49R.Kroeger,49J.Reidy,49D.A.Sanders,49D.J.Summers,49H.W.Zhao,49S.Brunet,50D.C?o t′e,50 P.Taras,50H.Nicholson,51N.Cavallo,52,?F.Fabozzi,52,?C.Gatto,52L.Lista,52D.Monorchio,52P.Paolucci,52
D.Piccolo,52C.Sciacca,52M.Baak,53H.Bulten,53G.Raven,53H.L.Snoek,53L.Wilden,53C.P.Jessop,54
J.M.LoSecco,54T.Allmendinger,55G.Benelli,55K.K.Gan,55K.Honscheid,55D.Hufnagel,55H.Kagan,55 R.Kass,55T.Pulliam,55A.M.Rahimi,55R.Ter-Antonyan,55Q.K.Wong,55J.Brau,56R.Frey,56O.Igonkina,56 M.Lu,56C.T.Potter,56N.B.Sinev,56D.Strom,56E.Torrence,56F.Colecchia,57A.Dorigo,57F.Galeazzi,57 M.Margoni,57M.Morandin,57M.Posocco,57M.Rotondo,57F.Simonetto,57R.Stroili,57C.Voci,57 M.Benayoun,58H.Briand,58J.Chauveau,58P.David,58Ch.de la Vaissi`e re,58L.Del Buono,58O.Hamon,58 M.J.J.John,58Ph.Leruste,58J.Malcles,58J.Ocariz,58L.Roos,58G.Therin,58P.K.Behera,59L.Gladney,59 Q.H.Guo,59J.Panetta,59C.Angelini,60G.Batignani,60S.Bettarini,60M.Bondioli,60F.Bucci,60G.Calderini,60 M.Carpinelli,60F.Forti,60M.A.Giorgi,60A.Lusiani,60G.Marchiori,60M.Morganti,60N.Neri,60E.Paoloni,60 M.Rama,60G.Rizzo,60G.Simi,60J.Walsh,60M.Haire,61D.Judd,61K.Paick,61D.E.Wagoner,61N.Danielson,62 P.Elmer,https://www.sodocs.net/doc/bd15544408.html,u,62C.Lu,62V.Miftakov,62J.Olsen,62A.J.S.Smith,62A.V.Telnov,62F.Bellini,63
G.Cavoto,62,63A.D’Orazio,63E.Di Marco,63R.Faccini,63F.Ferrarotto,63F.Ferroni,63M.Gaspero,63
L.Li Gioi,63M.A.Mazzoni,63S.Morganti,63M.Pierini,63G.Piredda,63F.Polci,63F.Safai Tehrani,63
C.Voena,63S.Christ,64H.Scroeder,64G.Wagner,64R.Waldi,64T.Adye,65N.De Groot,65B.Franek,65
G.P.Gopal,65E.O.Olaiya,65R.Aleksan,66S.Emery,66A.Gaidot,66S.F.Ganzhur,66P.-F.Giraud,66
G.Hamel de Monchenault,66W.Kozanecki,66M.Legendre,66G.W.London,66B.Mayer,66G.Schott,66
G.Vasseur,66Ch.Y`e che,66M.Zito,66M.V.Purohit,67A.W.Weidemann,67J.R.Wilson,67F.X.Yumiceva,67 T.Abe,68M.Allen,68D.Aston,68R.Bartoldus,68N.Berger,68A.M.Boyarski,68O.L.Buchmueller,68R.Claus,68 M.R.Convery,68M.Cristinziani,68G.De Nardo,68J.C.Dingfelder,68D.Dong,68J.Dorfan,68D.Dujmic,68 W.Dunwoodie,68S.Fan,68R.C.Field,68T.Glanzman,68S.J.Gowdy,68T.Hadig,68V.Halyo,68C.Hast,68 T.Hryn’ova,68W.R.Innes,68M.H.Kelsey,68P.Kim,68M.L.Kocian,68D.W.G.S.Leith,68J.Libby,68 S.Luitz,68V.Luth,68H.L.Lynch,68H.Marsiske,68R.Messner,68D.R.Muller,68C.P.O’Grady,68V.E.Ozcan,68
A.Perazzo,68M.Perl,68
B.N.Ratcli?,68A.Roodman,68A.A.Salnikov,68R.H.Schindler,68J.Schwiening,68
A.Snyder,68A.Soha,68J.Stelzer,68J.Strube,56,68D.Su,68M.K.Sullivan,68J.Thompson,68J.Va’vra,68 S.R.Wagner,68M.Weaver,68W.J.Wisniewski,68M.Wittgen,68D.H.Wright,68A.K.Yarritu,68C.C.Young,68 P.R.Burchat,69A.J.Edwards,69S.A.Majewski,69
B.A.Petersen,69
C.Roat,69M.Ahmed,70S.Ahmed,70 M.S.Alam,70J.A.Ernst,70M.A.Saeed,70M.Saleem,70F.R.Wappler,70W.Bugg,71M.Krishnamurthy,71 S.M.Spanier,71R.Eckmann,72H.Kim,72J.L.Ritchie,72A.Satpathy,72R.F.Schwitters,72J.M.Izen,73
I.Kitayama,73X.C.Lou,73S.Ye,73F.Bianchi,74M.Bona,74F.Gallo,74D.Gamba,74L.Bosisio,75C.Cartaro,75
F.Cossutti,75
G.Della Ricca,75S.Dittongo,75S.Grancagnolo,https://www.sodocs.net/doc/bd15544408.html,nceri,75P.Poropat,75,?L.Vitale,75
G.Vuagnin,75F.Martinez-Vidal,2,76R.S.Panvini,77Sw.Banerjee,78B.Bhuyan,78C.M.Brown,78D.Fortin,78 P.D.Jackson,78R.Kowalewski,78J.M.Roney,78R.J.Sobie,78J.J.Back,79P.F.Harrison,79G.B.Mohanty,79 H.R.Band,80X.Chen,80B.Cheng,80S.Dasu,80M.Datta,80A.M.Eichenbaum,80K.T.Flood,80M.Graham,80
J.J.Hollar,80J.R.Johnson,80P.E.Kutter,80H.Li,80R.Liu,80A.Mihalyi,80Y.Pan,80R.Prepost,80 P.Tan,80J.H.von Wimmersperg-Toeller,80J.Wu,80S.L.Wu,80Z.Yu,80M.G.Greene,81and H.Neal81
(The B A B A R Collaboration)
1Laboratoire de Physique des Particules,F-74941Annecy-le-Vieux,France
2Universitad Autonoma de Barcelona,E-08193Bellaterra,Barcelona,Spain
3Universit`a di Bari,Dipartimento di Fisica and INFN,I-70126Bari,Italy
4Institute of High Energy Physics,Beijing100039,China
5University of Bergen,Inst.of Physics,N-5007Bergen,Norway
6Lawrence Berkeley National Laboratory and University of California,Berkeley,CA94720,USA
7University of Birmingham,Birmingham,B152TT,United Kingdom
8Ruhr Universit¨a t Bochum,Institut f¨u r Experimentalphysik1,D-44780Bochum,Germany
9University of Bristol,Bristol BS81TL,United Kingdom
10University of British Columbia,Vancouver,BC,Canada V6T1Z1
11Brunel University,Uxbridge,Middlesex UB83PH,United Kingdom
12Budker Institute of Nuclear Physics,Novosibirsk630090,Russia
13University of California at Irvine,Irvine,CA92697,USA
14University of California at Los Angeles,Los Angeles,CA90024,USA
15University of California at Riverside,Riverside,CA92521,USA
16University of California at San Diego,La Jolla,CA92093,USA
17University of California at Santa Barbara,Santa Barbara,CA93106,USA 18University of California at Santa Cruz,Institute for Particle Physics,Santa Cruz,CA95064,USA
19California Institute of Technology,Pasadena,CA91125,USA
20University of Cincinnati,Cincinnati,OH45221,USA
21University of Colorado,Boulder,CO80309,USA
22Colorado State University,Fort Collins,CO80523,USA
23Universit¨a t Dortmund,Institut fur Physik,D-44221Dortmund,Germany
24Technische Universit¨a t Dresden,Institut f¨u r Kern-und Teilchenphysik,D-01062Dresden,Germany
25Ecole Polytechnique,LLR,F-91128Palaiseau,France
26University of Edinburgh,Edinburgh EH93JZ,United Kingdom
27Universit`a di Ferrara,Dipartimento di Fisica and INFN,I-44100Ferrara,Italy
28Florida A&M University,Tallahassee,FL32307,USA
29Laboratori Nazionali di Frascati dell’INFN,I-00044Frascati,Italy
30Universit`a di Genova,Dipartimento di Fisica and INFN,I-16146Genova,Italy
31Harvard University,Cambridge,MA02138,USA
32Universit¨a t Heidelberg,Physikalisches Institut,Philosophenweg12,D-69120Heidelberg,Germany
33Imperial College London,London,SW72AZ,United Kingdom
34University of Iowa,Iowa City,IA52242,USA
35Iowa State University,Ames,IA50011-3160,USA
36Universit`a di Perugia,Dipartimento di Fisica and INFN,I-06100Perugia,Italy
37Laboratoire de l’Acc′e l′e rateur Lin′e aire,F-91898Orsay,France
38Lawrence Livermore National Laboratory,Livermore,CA94550,USA
39University of Liverpool,Liverpool L6972E,United Kingdom
40Queen Mary,University of London,E14NS,United Kingdom
41University of London,Royal Holloway and Bedford New College,Egham,Surrey TW200EX,United Kingdom
42University of Louisville,Louisville,KY40292,USA
43University of Manchester,Manchester M139PL,United Kingdom
44University of Maryland,College Park,MD20742,USA
45University of Massachusetts,Amherst,MA01003,USA
46Massachusetts Institute of Technology,Laboratory for Nuclear Science,Cambridge,MA02139,USA
47McGill University,Montr′e al,QC,Canada H3A2T8
48Universit`a di Milano,Dipartimento di Fisica and INFN,I-20133Milano,Italy
49University of Mississippi,University,MS38677,USA
50Universit′e de Montr′e al,Laboratoire Ren′e J.A.L′e vesque,Montr′e al,QC,Canada H3C3J7
51Mount Holyoke College,South Hadley,MA01075,USA
52Universit`a di Napoli Federico II,Dipartimento di Scienze Fisiche and INFN,I-80126,Napoli,Italy
53NIKHEF,National Institute for Nuclear Physics and High Energy Physics,NL-1009DB Amsterdam,The Netherlands 54University of Notre Dame,Notre Dame,IN46556,USA
55Ohio State University,Columbus,OH43210,USA
56University of Oregon,Eugene,OR97403,USA
57Universit`a di Padova,Dipartimento di Fisica and INFN,I-35131Padova,Italy 58Universit′e s Paris VI et VII,Laboratoire de Physique Nucl′e aire et de Hautes Energies,F-75252Paris,France
59University of Pennsylvania,Philadelphia,PA19104,USA
60Universit`a di Pisa,Dipartimento di Fisica,Scuola Normale Superiore and INFN,I-56127Pisa,Italy
61Prairie View A&M University,Prairie View,TX77446,USA
62Princeton University,Princeton,NJ08544,USA
63Universit`a di Roma La Sapienza,Dipartimento di Fisica and INFN,I-00185Roma,Italy
64Universit¨a t Rostock,D-18051Rostock,Germany
65Rutherford Appleton Laboratory,Chilton,Didcot,Oxon,OX110QX,United Kingdom
66DSM/Dapnia,CEA/Saclay,F-91191Gif-sur-Yvette,France
67University of South Carolina,Columbia,SC29208,USA
68Stanford Linear Accelerator Center,Stanford,CA94309,USA
69Stanford University,Stanford,CA94305-4060,USA
70State University of New York,Albany,NY12222,USA
71University of Tennessee,Knoxville,TN37996,USA
72University of Texas at Austin,Austin,TX78712,USA
73University of Texas at Dallas,Richardson,TX75083,USA
74Universit`a di Torino,Dipartimento di Fisica Sperimentale and INFN,I-10125Torino,Italy
75Universit`a di Trieste,Dipartimento di Fisica and INFN,I-34127Trieste,Italy
76Universitad de Valencia,E-46100Burjassot,Valencia,Spain
77Vanderbilt University,Nashville,TN37235,USA
78University of Victoria,Victoria,BC,Canada V8W3P6
79Department of Physics,University of Warwick,Coventry CV47AL,United Kingdom
80University of Wisconsin,Madison,WI53706,USA
81Yale University,New Haven,CT06511,USA
(Dated:February6,2008)
We search for a charged partner of the X(3872)in the decay B→X?K,X?→J/ψπ?π0,using
234million B
K0,X?→J/ψπ?π0)<22×10?6 at the90%con?dence level.
PACS numbers:13.25.Hw,14.40.Gx,12.39.Mk
The discovery of the X(3872)by the Belle Collabo-
ration[1],has been con?rmed by the CDF[2],D0[3]and
B A B A R[4]Collaborations.Numerous theoretical expla-
nations have been proposed for this high-mass,narrow-
width state decaying into J/ψπ+π?.The possibilities[5]
include a bound state of D?D0
threshold[6],a hybrid charmonium state[7],a diquark-
antidiquark state[8],and a conventional charmonium
state[9].The Cornell potential model[10]predicts a
3D2(J P C=2??)charmonium state with a3.830GeV/c2
mass.This state is expected to be very narrow since the
decay to D
B events(N
B
5
m ES ≡
n mc b )
[16],
where a ,the number
of standard deviations of signi?cance desired,was set to 3.Note that the maximum of this ratio is independent of the unknown signal branching fraction.This ratio was maximized by varying the selection criteria on ?E ,m ES ,
the X ?(J/ψπ?π0)mass,the K 0S (π+π?)mass,the K 0
S decay-length signi?cance,the γγinvariant mass,and the particle-identi?cation criteria for electrons,muons and charged kaons.When there was more than one candi-date per event after applying the optimized cuts (on aver-age there were 1.3candidates/event),the candidate with the smallest value of |?E |was chosen.The selections |m ES ?m B |<5MeV /c 2and |?E |<20MeV (signal-box region)were found to be optimal for selecting signal events.The plots that follow include only one candidate per event,except for the plots showing ?E itself.
The ?E and m ES distributions for the neutral and charged B modes after we apply all the optimized cuts,FIG.1:The ?E (a)and m ES (b)distributions for the B 0→J/ψπ?π0K +mode and the ?E (c)and m ES (d)distributions
for the B ?→J/ψπ?π0K 0
S mode using the optimized cuts.The dotted line shows the same with the additional cut 0.67 ?E distribution and near 5.279GeV /c 2in the m ES dis-tribution.The other feature in the ?E plots is a wide peak near 0.2GeV which is due to B →J/ψK ?decays combined with a random pion. The Dalitz plots in Fig.2for the charged-and neutral-B modes use events in the signal-box region and in-clude a mass cut of 0.67 FIG.2:The m 2(J/ψρ?)versus the m 2(ρ?K +)distributions (a)for B 0→J/ψπ?π0K +and the m 2(J/ψρ?)versus the m 2(ρ?K 0S )distributions (b)for B ?→J/ψπ?π0K 0 S .A B →J/ψK 1signal can be seen,however there is no indication for an enhancement in the J/ψρ?mass spectrum. K 01(1270)→K +ρ?and K ?1(1270)→K 0S ρ? correspond-ing to the decays B ?→J/ψK ?1and B 0→J/ψK 01pre-viously observed by Belle [17]. The J/ψπ?π0mass spectra from the neutral and charged B modes are shown in Fig.3without a ρmass cut.No charged signal,X ?→J/ψπ?π0,is evident at 3.872GeV /c 2. FIG.3:The J/ψπ?π0invariant mass in 10MeV /c 2bins for (a)B 0→J/ψπ?π0K +and (b)for B ?→J/ψπ?π0K 0 S .No indication for the decay X ?→J/ψπ?π0 can be found. Extracting an upper limit for X ?→J/ψπ?π0requires examining the J/ψπ?π0mass,m ES ,and ?E distribu-tions.A signal from B →X ?K ,X ?→J/ψπ?π0should produce signal peaks in all three distributions.Back-ground from B →J/ψπ?π0K in which the J/ψπ?π0is nonresonant would produce peaks in the m ES and ?E distributions but have a ?at J/ψπ?π0mass distribution near 3.872GeV /c 2.The combinatoric background will not create peaks in any of the three distributions and should produce an m ES distribution whose shape can be parametrized by an ARGUS function [18].To estimate 6 the number of signal events(n S),we count the number of observed events(n obs)in the signal region and subtract the estimated number of combinatoric background events (n comb)and the estimated number of peaking background events(n peak). We obtain n obs by counting the number of events satisfying|m ES?m B|<5MeV/c2,|?E|<20MeV, and m(J/ψπ?π0)?3872 <12MeV/c2.We extract n comb from the m ES distribution obtained after requir- ing|?E|<20MeV,and m J/ψπ?π0 ?3872 < 12MeV/c2.These m ES distributions for the neutral and charged B modes are separately?t with the sum of a signal Gaussian function and an ARGUS function.The resulting ARGUS function is integrated over the m ES range,|m ES?m B|<5MeV/c2,to produce n comb.The errorσcomb is obtained from the?t error on the normal-ization of the ARGUS function.The resulting values for n comb andσcomb are listed in Table1. TABLE I:E?ciencies,number of signal-box events,and es-timated number of background events n b(n peak+n comb)for the neutral and charged B decays. Mode?n obs n peak±σpeak n comb±σcomb n b±σb We extract n peak from the m ES distribution ob- tained after requiring|?E|<20MeV,and48< m J/ψπ?π0 ?3872 <72MeV/c2which is twice the mass range of the signal band.These m ES distributions for the neutral-and charged-B modes are separately?t with the sum of a Gaussian function and an ARGUS function.We calculate n peak by counting the number of events in the|m ES?m B|<5MeV/c2region,subtract-ing the number of combinatoric events obtained from integrating the ARGUS function over the same range, |m ES?m B|<5MeV/c2,and?nally dividing the result by two.Note that the Gaussian distribution used in all ?ts has a width?xed to the value determined from a?t to the m ES distribution obtained using both the J/ψπ?π0 signal band and the J/ψπ?π0sideband.The errorσpeak is obtained by adding in quadrature the Poisson errors on the number of events in|m ES?m B|<5MeV/c2and the?t errors on the normalization of the ARGUS func-tion.The resulting values for n peak and σpeak are listed in Table I. The total background n b is the sum of the peaking and combinatoric backgrounds and its errorσb combines in quadrature the errors from the peaking and combina-toric backgrounds.The backgrounds and their errors are summarized in Table I. The e?ciencies?for the processes,B0→X?K+, X?→J/ψπ?π0and B?→X?K0 S ,X?→J/ψπ?π0 are determined by MC simulation with an X?signal of zero width,mass3.872GeV/c2,and a model consisting of the sequential isotropic two-body decays B→X?K, X?→J/ψρ?andρ?→π?π0. These e?ciencies are corrected to account for the small di?erences observed in PID,neutral-particle detection, and tracking e?ciency that are found by comparing well-understood control samples taken from data and MC. The?nal e?ciencies for each mode are listed in Table I. The systematic errors include uncertainties in the num-ber of B N B TOTAL(σsys)8.89.7 n obs+σ2 b +n2sσ2sys. The systematic error is added in quadrature and scales the errors on n obs and n b by the same fraction.We note the mean values n s,for the charged and neutral modes are consistent with zero,within errors. The number of events N90corresponding to the90% con?dence level(C.L.)upper limit is calculated using the Gaussian probability distribution with the assump-tion that the number of signal events is always greater 7 than zero.The integral of the distribution from zero to N90will be90%of the total area above https://www.sodocs.net/doc/bd15544408.html,-bining N90,?,N B B0?16.8±14.715.9<5.4?5.7±4.9 B?4.7±8.817.8<112.0±3.8 B events.The error combines the uncertainty on the branching frac-tion and the systematic errorσsys on our e?ciency.The probability distributions for the signal events and the es-timated background events are modeled as two uncorre-lated Gaussian functions.The probability of observing 96or fewer events(including background)with this prob-ability distribution is P(H1)=8.41×10?5. The likelihood ratio(λ)test of the null hypothesis rel-ative to the signal hypothesis yieldsλ=P(H0)/P(H1) =692.This corresponds to a probability of less than1 part in600that the isovector-X hypothesis is compat-ible with the outcome of our search for B0→X?K+, X?→J/ψπ?π0.Performing the same study in our search for B?→X?K0 S ,X?→J/ψπ?π0we obtain λ=17.The combined likelihood ratio is1.1×104.Our result does not support the hypothesis that the X(3872)is an isovector particle decaying to J/ψρ. In conclusion,we have performed a search for a charged partner of the X(3872)decaying to J/ψπ?π0. Our results set upper limits on the product branch-ing fractions of B(B0→X?K+,X?→J/ψπ?π0)< 5.4×10?6and B(B?→X? 8 Phys.Rev.D69,074005(2004);E.Swanson,Phys.Lett. B588,189(2004). [7]F.Close and S.Godfrey,Phys.Lett.B574,210(2003). [8]L.Maiani,F.Piccinini,A.D.Polosa,and V.Riquer,hep- ph/0412098 [9]E.Eichten,https://www.sodocs.net/doc/bd15544408.html,ne,and C.Quigg,Phys.Rev.Lett.89, 162002(2002);T.Barnes and S.Godfrey,Phys.Rev.D 69,054008(2004). [10]E.Eichten,https://www.sodocs.net/doc/bd15544408.html,ne,and C.Quigg,Phys.Rev.D69, 094019(2004). [11]Charge conjugate reactions are included implicitly throughout. [12]B A B A R Collaboration,B.Aubert et al.,Nucl.Instr.and Methods A479,1(2002). [13]B A B A R Collaboration,B.Aubert et al.,Phys.Rev.D65, 032001(2002). [14]B A B A R Collaboration,B.Aubert et al.,Phys.Rev.D66, 032003(2002). [15]Particle Data Group,S.Eidelman et al.,Phys.Lett.B 592,1(2004),see section32.2.1for a discussion of the likelihood ratio test. [16]G.Punzi,“Sensitivity of searches for new signals and its optimization,”eprint physics/0308063 [17]Belle Collaboration,K.Abe et al.,Phys.Rev.Lett.87, 161601(2001). [18]The original ARGUS function is described in H.Albrecht et al.,Phys.Lett.B185,218(1987);Phys.Lett.B241, 278(1990). [19]S.Pakvasa and M.Suzuki,Phys.Lett.B579,67(2004). In this reference the authors assume the relative orbital angular momentum between the J/ψand the di-pion state is L=0.This is justi?ed for di-pion events near the kinematic upper limit.