Measurement of the Branching Fraction for D^+ to K^- pi^+ pi^+
a r X i v :h e p -p h /9403382v 1 29 M a r 1994
CLNS 94/1267
CLEO 94-2
February 1,2008
Measurement of the branching fraction for D +→K ?π+π+
R.Balest,1K.Cho,1M.Daoudi,1W.T.Ford,1D.R.Johnson,1K.Lingel,1M.Lohner,1P.Rankin,1J.G.Smith,1J.P.Alexander,2C.Bebek,2K.Berkelman,2K.Bloom,2T.E.Browder,2?D.G.Cassel,2H.A.Cho,2D.M.Co?man,2P.S.Drell,2R.Ehrlich,2P.Gaiderev,2M.Garcia-Sciveres,2B.Geiser,2B.Gittelman,2S.W.Gray,2D.L.Hartill,2
B.K.Heltsley,2
C.
D.Jones,2S.L.Jones,2J.Kandaswamy,2N.Katayama,2P.C.Kim,2
D.L.Kreinick,2G.S.Ludwig,2J.Masui,2J.Mevissen,2N.B.Mistry,2C.R.Ng,2
E.Nordberg,2J.R.Patterson,2D.Peterson,2D.Riley,2S.Salman,2M.Sapper,2
F.W¨u rthwein,2P.Avery,3A.Freyberger,3J.Rodriguez,3R.Stephens,3S.Yang,3J.Yelton,3D.Cinabro,4S.Henderson,4T.Liu,4M.Saulnier,4R.Wilson,4H.Yamamoto,4T.Bergfeld,5B.I.Eisenstein,5
G.Gollin,5B.Ong,5M.Palmer,5M.Selen,5J.J.Thaler,5
A.J.Sado?,6R.Ammar,7S.Ball,7P.Baringer,7A.Bean,7D.Besson,7D.Coppage,7N.Copty,7R.Davis,7N.Hancock,7M.Kelly,7N.Kwak,https://www.wendangku.net/doc/0b19364096.html,m,7Y.Kubota,https://www.wendangku.net/doc/0b19364096.html,ttery,8J.K.Nelson,8S.Patton,8D.Perticone,8R.Poling,8V.Savinov,8S.Schrenk,8R.Wang,8M.S.Alam,9I.J.Kim,9
B.Nemati,9J.J.O’Neill,9H.Severini,9
C.R.Sun,9M.M.Zoeller,9G.Crawford,10C.M.Daubenmier,10R.Fulton,10
D.Fujino,10K.K.Gan,10K.Honscheid,10H.Kagan,10R.Kass,10J.Lee,10R.Malchow,10Y.Skovpen,10?M.Sung,10
C.White,10F.Butler,11X.Fu,11G.Kalb?eisch,11W.R.Ross,11P.Skubic,11J.Snow,11
P.L.Wang,11M.Wood,11D.N.Brown,12J.Fast ,12R.L.McIlwain,12T.Miao,12
https://www.wendangku.net/doc/0b19364096.html,ler,12M.Modesitt,12D.Payne,12
E.I.Shibata,12I.P.J.Shipsey,12P.N.Wang,12M.Battle,13J.Ernst,13Y.Kwon,13S.Roberts,13E.H.Thorndike,13C.H.Wang,13J.Dominick,https://www.wendangku.net/doc/0b19364096.html,mbrecht,14S.Sanghera,14V.Shelkov,14T.Skwarnicki,14
R.Stroynowski,14I.Volobouev,14G.Wei,14P.Zadorozhny,14M.Artuso,15M.Goldberg,15
D.He,15N.Horwitz,15R.Kennett,15R.Mountain,15G.C.Moneti,15F.Muheim,15Y.Mukhin,15S.Playfer,15Y.Rozen,15S.Stone,15M.Thulasidas,15G.Vasseur,15G.Zhu,15
J.Bartelt,16S.E.Csorna,16Z.Egyed,16V.Jain,16K.Kinoshita,17K.W.Edwards,18M.Ogg,18D.I.Britton,19E.R.F.Hyatt,19D.B.MacFarlane,19P.M.Patel,19D.S.Akerib,20
B.Barish,20M.Chadha,20S.Chan,20D.F.Cowen,20G.Eigen,https://www.wendangku.net/doc/0b19364096.html,ler,20
C.O’Grady,20J.Urheim,20A.J.Weinstein,20
D.Acosta,21M.Athanas,21G.Masek,21H.P.Paar,21J.Gronberg,22R.Kutschke,22S.Menary,22R.J.Morrison,22S.Nakanishi,22
H.N.Nelson,22T.K.Nelson,22C.Qiao,22J.D.Richman,22A.Ryd,22H.Tajima,22
D.Sperka,22M.S.Witherell,22and M.Procario 23
(CLEO Collaboration)
1University of Colorado,Boulder,Colorado80309-0390
2Cornell University,Ithaca,New York14853
3University of Florida,Gainesville,Florida32611
4Harvard University,Cambridge,Massachusetts02138
5University of Illinois,Champaign-Urbana,Illinois,61801
6Ithaca College,Ithaca,New York14850
7University of Kansas,Lawrence,Kansas66045
8University of Minnesota,Minneapolis,Minnesota55455
9State University of New York at Albany,Albany,New York12222
10Ohio State University,Columbus,Ohio,43210
11University of Oklahoma,Norman,Oklahoma73019
12Purdue University,West Lafayette,Indiana47907
13University of Rochester,Rochester,New York14627
14Southern Methodist University,Dallas,Texas75275
15Syracuse University,Syracuse,New York13244
16Vanderbilt University,Nashville,Tennessee37235
17Virginia Polytechnic Institute and State University,Blacksburg,Virginia,24061
18Carleton University,Ottawa,Ontario K1S5B6and the Institute of Particle Physics,Canada 19McGill University,Montr′e al,Qu′e bec H3A2T8and the Institute of Particle Physics,Canada 20California Institute of Technology,Pasadena,California91125
21University of California,San Diego,La Jolla,California92093
22University of California,Santa Barbara,California93106
23Carnegie-Mellon University,Pittsburgh,Pennsylvania15213
(February1,2008)
Abstract
Using the CLEO-II detector at CESR we have measured the ratio of branching
fractions,B(D+→K?π+π+)/B(D0→K?π+)=2.35±0.16±0.16.Our
recent measurement of B(D0→K?π+)then gives B(D+→K?π+π+)=
(9.3±0.6±0.8)%.
PAC numbers:13.20.Fc,13.25.Ft,14.40.Lb
Typeset using REVT E X
The decay D+→K?π+π+is the most commonly used mode for normalizing D+ yields,since it has a relatively large branching fraction and is one of the simplest to re-construct.Many current charm and bottom meson decay results are limited by the precision of B(D+→K?π+π+).Previous measurements of this decay mode were performed by the Mark III[1]and ACCMOR[2]collaborations.Mark III used the relative number of singly detected D±mesons to the number of reconstructed D+D?events to determine the branch-ing fraction.The ACCMOR collaboration measured the ratio of D+→K?π+π+relative to the total number of3-prong decays,and used topological branching ratios determined by other experiments to obtain a branching fraction.However,ACCMOR could not eas-ily distinguish D+,D+s andΛ+c decay vertices,and had to rely on estimates of the relative production ratios of these particles.In this analysis,we use the exclusive yields,N Kπand N Kππ,of the(D?+→D0π+,D0→K?π+)and the(D?+→D+π0,D+→K?π+π+)de-cay sequences,respectively,to measure the ratio,B(D+→K?π+π+)/B(D0→K?π+), and apply our measurement of the branching fraction for B(D0→K?π+)[3]to obtain B(D+→K?π+π+).
The data used in this analysis consist of1.79fb?1of e+e?collisions recorded with the CLEO-II detector operating at the Cornell Electron Storage Ring(CESR).The CLEO-II detector has been described in detail elsewhere[4].Data were recorded at theΥ(4S) resonance and in the continuum both below and above(the e+e?center of mass energies ranged from10.52to10.70GeV).
We obtain clean samples of D?mesons by requiring theπ0and theπ+emitted in their decays to ful?ll strict selection criteria.To reconstructπ0’s,we start with neutral showers which satisfy isolation cuts and cannot be matched to any charged track in the event.These photons candidates must have|cosθγ|≤0.71,(θγis the polar angle measured relative to the beam axis)to ensure that they lie in that portion of the electromagentic calorimeter which has the best e?ciency and resolution,and the least systematic uncertainty.In addition,photon energies have to be greater than30MeV.We then kinematically constrainγγcombinations with masses between125and145MeV/c2to the knownπ0mass to improve the momentum resolution.To reduceγγcombinatoric background,π0candidates are required to have momenta greater than200MeV/c.In addition,the kinematically constrainedπ0candidates must have|cosθπ0|≤0.70.Charged pions are selected if they have momentum greater than200MeV/c,and|cosθπ±|≤0.70.The polar angle cuts onπ+’s andπ0’s ensure that D?+mesons reconstructed with either charged or neutral pions have the same geometric acceptance.
The ratio N Kππ/N Kπof the measured yields can be expressed in terms of branching ratios and e?ciencies as,
N Kππ
(1)
N D?+B(D?+→D0π+)B Kπ?Kπ
where B Kππand B Kπare the relevant D+and D0branching fractions,respectively.The total number of D?+’s produced in the data sample is N D?+(which cancels in the ratio);?Kππand ?Kπare the e?ciencies for reconstructing D+→K?π+π+and D0→K?π+,respectively, with their respective D?+https://www.wendangku.net/doc/0b19364096.html,ing isospin invariance,the CLEO-II measurements of the D?+?D+and D?+?D0mass di?erences[5],and the fact that these decays are p-wave,we estimate the ratio[6]
B(D?+→π+D0)
B(D+→K?π+π+)
REFERENCES
[1]Mark III Collaboration,J.Adler et al.,Phys.Rev.Lett.60,89(1988)
[2]ACCMOR Collaboration,S.Barlag et al.,Z.Phys.C55,383(1992);S.Barlag et al.,
Z.Phys.C48,29(1990).
[3]CLEO Collaboration,D.Akerib et al.,Phys.Rev.Lett.71,3070(1993).
[4]CLEO Collaboration,Y.Kubota et al.,Nucl.Intr.and Meth.A320,66(1992).
[5]CLEO Collaboration,D.Bortoletto et al.,Phys.Rev.Lett.69,2046(1992).
[6]CLEO Collaboration,F.Butler et al.,Phys.Rev.Lett.69,2041(1992).
[7]The average momentum for slow pions emitted in D?decays which pass the selection
criteria is approximately260MeV/c,whereas the average momenta of the D decay daughters is approximately1.3GeV/c for D+and1.7GeV/c for D0.The e?ciency for reconstructing kaons and pions from D decays is known to an accuracy of±2%[3].
[8]Particle Data Group,K.Hikasa et al.,Phys.Rev.45,1(1992).
[9]The scale factor is such that the number of events in the sideband region is the same as
the number of events in the background under the mass di?erence signal.We investigated di?erent mass di?erence sidebands to estimate the systematic error associated with this technique.The yields quoted in the text are obtained from the sideband where the D?+?D mass di?erence is in the range146.6-155.6MeV/c2for D?+?D+,and151.4 -160.4MeV/c2for D?+?D0.
[10]The e?ect of?nal state decay radiation on D0→K?π+and D+→K?π+π+is to
reduce their reconstruction e?ciencies by approximately1%.Therefore,the ratio of the two e?ciencies,?Kπand?Kππis very insensitive to the e?ects of decay radiation.We used the program PHOTOS to estimate these e?ects-E.Barberio,B.van Eijk and Z.
Was,https://www.wendangku.net/doc/0b19364096.html,mun.66115(1991).
FIGURES
FIG.1.Mass distribution for D+→K?π+π+candidates tagged via D?+→D+π0decays;the histogram represent events in the mass di?erence signal region,triangles with error bars represent events in the(scaled)mass di?erence sideband region.The solid line is the?t to the data.
FIG.2.Mass distribution for D0→K?π+tagged via D?+→D0π+decays;the histogram represent events in the mass di?erence signal region,triangles represent events in the(scaled)mass di?erence sideband region.The solid line is the?t to the data.
This figure "fig1-1.png" is available in "png" format from: https://www.wendangku.net/doc/0b19364096.html,/ps/hep-ph/9403382v1
This figure "fig1-2.png" is available in "png" format from: https://www.wendangku.net/doc/0b19364096.html,/ps/hep-ph/9403382v1