-
N Gabyshev,
K Abe,
I Adachi,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
A M Bakich,
U Bitenc,
I Bizjak, [......],
H Yamamoto,
Y Yamashita,
M Yamauchi, Heyoung Yang,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: Using a sample of 152 x 10(6) BB pairs accumulated with the Belle detector at the KEKB e+e- collider, we study the decay mechanism of three-body charmed decay B- --> Lambdac+ ppi-. The intermediate two-body decay B--->Sigmac (2455)0 p is observed for the first time with a branching fraction of (3.7 +/- 0.7 +/- 0.4 +/- 1.0) x 10(-5) and a statistical significance of 8.4sigma. We also observe a low-mass enhancement in the (Lambdac+p) system, which can be parametrized as a Breit-Wigner function with a mass of (3.35(-0.02)(+0.01) +/-0.02) GeV/c2 and a width of (0.07(-0.03)(+0.04) +/-0.04) GeV/c2. We measure its branching fraction to be (3.9(-0.7)(+0.8) +/- 0.4 +/- 1.0) x 10(-5) with a statistical significance of 6.2sigma. The errors are statistical, systematic, and that of the Lambdac+-->pK- pi+ decay branching fraction.
Physical Review Letters 12/2006; 97(24):242001. · 7.37 Impact Factor
-
A Garmash,
K Abe,
I Adachi,
H Aihara,
Y Asano,
T Aushev,
T Aziz,
S Bahinipati,
A M Bakich,
M Barbero, [......],
Y Watanabe,
E Won,
Q L Xie,
A Yamaguchi,
M Yamauchi, Heyoung Yang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report results on a Dalitz analysis of three-body charmless B+/- --> K+/-pi+/-pi+/- decay including searches for direct CP violation. We report the first observation of the decay B+/- --> f2(1270)K+/- with a statistical significance above 6sigma. We also observe first evidence for large direct CP violation in the B+/- --> rho(770)0K+/- channel. The results are obtained with a data sample that contains 386 10(6) BB pairs collected at the Y(4s) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
Physical Review Letters 07/2006; 96(25):251803. · 7.37 Impact Factor
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I Bizjak,
K Abe,
H Aihara,
Y Asano,
S Bahinipati,
A M Bakich,
Y Ban,
E Barberio,
M Barbero,
A Bay, [......],
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi, Heyoung Yang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element /Vub/, based on 253 fb(-1) of data collected by the Belle detector at the KEKB e+ e- asymmetric collider. Events are tagged by fully reconstructing one of the B mesons, produced in pairs from Gamma(4S). The signal for b --> u semileptonic decay is distinguished from the b --> c background using the hadronic mass Mx, the leptonic invariant mass squared q2 and the variable P+ [triple bond] Ex - /px/. The results are obtained for events with p(l)* > or = 1 GeV/c, in three kinematic regions (1) Mx < 1.7 GeV/c2, (2) Mx < 1.7 GeV/c2 combined with q2 > 8 GeV2/c2, and by (3) P+ < 0.66 GeV/c. The matrix element /Vub/ is found to be (4.09 +/- 0.19 +/- 0.20(+0.14) -0.15 +/- 0.18) x 10(-3), where the errors are statistical, systematic including Monte Carlo modeling, theoretical, and from shape function parameter determination, respectively.
Physical Review Letters 12/2005; 95(24):241801. · 7.37 Impact Factor
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K Abe,
I Adachi,
H Aihara,
K Arinstein,
Y Asano,
T Aushev,
A M Bakich,
Y Ban,
E Barberio,
M Barbero, [......],
A Yamaguchi,
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We present a new measurement of the time-dependent CP-violating parameters in B(0)--> pi(+)pi(-) decays with 275 x 10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Gamma(4S) resonance. We find 666 +/- 43 B(0) --> pi(+)pi(-) events and measure the CP-violating parameters: S(pipi) = -0.67 +/- 0.16(stat) +/- 0.06(syst) and A(pipi) = +0.56 +/- 0.12(stat) +/- 0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any S(pipi) value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2) of 0 degree < phiv(2) < 19 degrees and 71 degrees < phi(2) < 180 degrees.
Physical Review Letters 10/2005; 95(10):101801. · 7.37 Impact Factor
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R Itoh,
Y Onuki,
K Abe,
I Adachi,
H Aihara,
Y Asano,
T Aushev,
A M Bakich,
Y Ban,
E Barberio, [......],
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: CP violation in B-->J/PsiK* decays is studied using an angular analysis in a data sample of 253 fb(-1) recorded with the Belle detector at the KEKB e(+)e(-) collider. The flavor separated measurements of the decay amplitudes indicate no evidence for direct CP violation. T-odd CP violation is studied using the asymmetries in triple product correlations, and the results are consistent with the standard model null predictions. The time-dependent angular analysis gives the following values of CP-violating parameters: sin(2phi(1) = 0.24 +/- 0.31 +/- 0.05 and cos(2phi(1)=0.56 +/- 0.79 +/- 0.11.
Physical Review Letters 09/2005; 95(9):091601. · 7.37 Impact Factor
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J Zhang,
K Abe,
I Adachi,
H Aihara,
K Arinstein,
Y Asano,
T Aushev,
T Aziz,
S Bahinipati,
A M Bakich, [......],
Y Watanabe,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita, Heyoung Yang,
J Ying,
L M Zhang,
Z P Zhang,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a study of the charmless vector-vector decay B+ --> rho+ K*0, based on 253 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. We obtain the branching fraction B(B+ --> rho+ K*0) = [8.9 +/- 1.7(stat) +/- 1.2(syst)] x 10(-6). We also perform a helicity analysis of the rho and K* vector mesons, and obtain the longitudinal polarization fraction f(L)(B+ --> rho+ K*0) = 0.43 +/- 0.11(stat)(-0.02)(+0.05) (syst).
Physical Review Letters 09/2005; 95(14):141801. · 7.37 Impact Factor
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Belle Collaboration,
Y. Enari,
N. Sato,
K. Abe,
H. Aihara,
Y. Asano,
V. Aulchenko,
S. Bahinipati,
A. M. Bakich,
I. Bedny, [......],
A. Yamaguchi,
Y. Yamashita,
M. Yamauchi, Heyoung Yang,
J. Ying,
J. Zhang,
L. M. Zhang,
Z. P. Zhang,
V. Zhilich,
D. Žontar
[show abstract]
[hide abstract]
ABSTRACT: We have searched for lepton flavor violating semileptonic
τ decays using a data sample of 153.8
fb-1 accumulated with the Belle detector at the KEKB
ee collider. For the six decay modes studied, the
observed yield is compatible with the estimated background and the
following upper limits are set at the 90% confidence level:
B(τ→eη)<2.3×10,
B(τ→μη)<1.5×10,
B(τ→eπ)<1.9×10,
B(τ→μπ)<4.1×10,
B(τ→eη)<10×10,
and
B(τ→μη)<4.7×10.
These results are 10 to 64 times more restrictive than previous limits.
Physics Letters B 08/2005; 622:218-228. · 3.95 Impact Factor
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K Sumisawa,
Y Ushiroda,
M Hazumi,
K Abe,
I Adachi,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
A M Bakich, [......],
A Yamaguchi,
H Yamamoto,
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of CP-violation parameters in the B0 --> K(s)0K(s)0K(s)0 decay based on a sample of 275 x 10(6) BB pairs collected at the upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in the decay B0 --> K(s)0K(s)0K(s)0, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distributions of the proper-time interval between the two B decays: S = +1.26 +/- 0.68(stat) +/- 0.20(syst) and [symbol: see text] = +0.54 +/- 0.34(stat) +/- 0.09(syst).
Physical Review Letters 08/2005; 95(6):061801. · 7.37 Impact Factor
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Y-J Lee,
M-Z Wang,
K Abe,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich,
I Bedny, [......],
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Ying,
C C Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of the radiative hyperonic B decay B+ --> plambdagamma, using a 140 fb(-1) data sample recorded on upsilom(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured branching fraction is [symbol: see text](B+ --> plambdagamma) = (2.16(+0.58)(-0.53) +/- 0.20) x 10(-6). We examine its M(plambda) distribution and observe a peak near threshold. This feature is expected by the short-distance b --> sgamma transition. A search for B+ --> pepsilon0gamma yields no significant signal, and we set a 90% confidence-level upper limit on the branching fraction of [symbol: see textB+ --> pepsilon0gamma <4.6 x 10(-6).
Physical Review Letters 08/2005; 95(6):061802. · 7.37 Impact Factor
-
Belle Collaboration,
C. C. Kuo,
K. Abe,
I. Adachi,
H. Aihara,
Y. Asano,
V. Aulchenko,
T. Aushev,
S. Bahinipati,
A. M. Bakich, [......],
A. Yamaguchi,
Y. Yamashita,
M. Yamauchi, Heyoung Yang,
J. Ying,
L. M. Zhang,
Z. P. Zhang,
V. Zhilich,
D. Žontar,
D. Zürcher
[show abstract]
[hide abstract]
ABSTRACT: A high precision study of the process γγ→pp¯ has
been performed using a data sample of 89 fb-1 collected
with the Belle detector at the KEKB ee collider.
The cross section of pp¯ production has been measured at two-photon
center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in the c.m.
angular range of |cosθ|<0.6. Production of
γγ→η→pp¯ is observed and the
product of the two-photon width of the η and its
branching ratio to pp¯ is determined.
Physics Letters B 07/2005; 621:41-55. · 3.95 Impact Factor
-
G Majumder,
K Abe,
I Adachi,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich,
S Banerjee, [......],
A Yamaguchi,
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Ying,
C C Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We report evidence for B(0) --> D(0)D(-) and the first observation of the decay modes B(-) --> D(0)D(-) and B(-) --> D(0)D(*-) based on a sample of 152 x 10(6) BB events collected by the Belle detector at KEKB. The branching fractions for B(0) --> D(+) D(-), B--->D(0)D(-), and B--> D(0)D(*-) are found to be (1.91 +/- 0.51 +/- 0.30) x10(-4), (4.83 +/- 0.78 +/- 0.58) x 10(-4), and (4.57 +/- 0.71 +/- 0.56) x 10(-4), respectively. Charge asymmetries in the B---> D(0)D(-) and B(-) --> D(0)D(*-) channels are consistent with zero.
Physical Review Letters 07/2005; 95(4):041803. · 7.37 Impact Factor
-
K-F Chen,
K Abe,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich,
I Bedny,
U Bitenc, [......],
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Ying,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We present measurements of decay amplitudes and triple-product correlations in B-->phiK* decays based on 253 fb(-1) of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. The decay amplitudes for the three different helicity states are determined from the angular distributions of final-state particles. The longitudinal polarization amplitudes are found to be 0.45 +/- 0.05 +/- 0.02 for B0-->phiK(*0) and 0.52 +/- 0.08 +/- 0.03 for B+ -->phiK(*+) decays. CP- and T-odd CP-violating triple-product asymmetries are measured to be consistent with zero.
Physical Review Letters 06/2005; 94(22):221804. · 7.37 Impact Factor
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Y Ushiroda,
K Sumisawa,
M Hazumi,
K Abe,
I Adachi,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
A M Bakich, [......],
Q L Xie,
A Yamaguchi,
Y Yamashita,
M Yamauchi, Heyoung Yang,
J Ying,
J Zhang,
L M Zhang,
Z P Zhang,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We present a new measurement of CP-violation parameters in B(0)-->K(0)(S)pi(0)gamma decay based on a sample of 275 x 10(6) BB pairs collected at the Gamma(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. One of the B mesons is fully reconstructed in the B(0)-->K(0)(S)pi(0)gamma decay. The flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetry in the distribution of the proper time intervals between the two B decays. We obtain SK(0)(S)(pi(0)gamma) = -0.58(+0.46)(-0.38)(stat) +/- 0.11(syst) and AK(0)(S)(pi(0)gamma) = +0.03 +/- 0.34(stat) +/- 0.11(syst), for the K(0)(S)pi(0) invariant mass covering the full range up to 1.8 GeV/c2. We also measure the CP-violation parameters for the case B(0)-->K(*0)(-->K(0)(S)pi(0))gamma and obtain S(K(*0)gamma) = -0.79(+0.63)(-0.50)(stat) +/- 0.10(syst) for A(K(*0)gamma) fixed at 0.
Physical Review Letters 06/2005; 94(23):231601. · 7.37 Impact Factor
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R Mizuk,
K Abe,
H Aihara,
M Akatsu,
Y Asano,
V Aulchenko,
T Aushev,
A M Bakich,
V Balagura,
Y Ban, [......],
M Yamauchi, Heyoung Yang,
J Ying,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of an isotriplet of excited charmed baryons, decaying into Lambda(+)(c)pi(-), Lambda(+)(c)pi(0), and Lambda(+)(c)pi(+). We measure the mass differences M(Lambda(+)(c)pi)-M(Lambda(+)(c)) and widths to be 515.4(+3.2+2.1)(-3.1-6.0) MeV/c(2), 61(+18+22)(-13-13) MeV for the neutral state; 505.4(+5.8+12.4)(-4.6-2.0) MeV/c(2), 62(+37+52)(-23-38) MeV for the charged state; and 514.5(+3.4+2.8)(-3.1-4.9) MeV/c(2), 75(+18+12)(-13-11) MeV for the doubly charged state, where the uncertainties are statistical and systematic, respectively. These results are obtained from a 281 fb(-1) data sample collected with the Belle detector near the Upsilon(4S) resonance, at the KEKB asymmetric energy e(+)e(-) collider.
Physical Review Letters 05/2005; 94(12):122002. · 7.37 Impact Factor
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S-K Choi,
S L Olsen,
K Abe,
I Adachi,
H Aihara,
Y Asano,
S Bahinipati,
A M Bakich,
Y Ban,
I Bedny, [......],
M Yamauchi, Heyoung Yang,
Y Yuan,
Y Yusa,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of a near-threshold enhancement in the omegaJ/psi invariant mass distribution for exclusive B-->KomegaJ/psi decays. The results are obtained from a 253 fb(-1) data sample that contains 275 x 10(6) BB pairs that were collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. The statistical significance of the omegaJ/psi mass enhancement is estimated to be greater than 8sigma.
Physical Review Letters 05/2005; 94(18):182002. · 7.37 Impact Factor
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Y Chao,
P Chang,
K Abe,
H Aihara,
K Akai,
M Akatsu,
M Akemoto,
Y Asano,
T Aushev,
S Bahinipati, [......],
K Yokoyama,
M Yoshida,
S L Zang,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of the decay B0-->pi(0)pi(0), using a 253 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. The measured branching fraction is B(B0-->pi(0)pi(0))=(2.3(+0.4+0.2)(-0.5-0.3))x10(-6), with a significance of 5.8 standard deviations including systematic uncertainties. We also make a measurement of the direct CP violating asymmetry in this mode.
Physical Review Letters 05/2005; 94(18):181803. · 7.37 Impact Factor
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Heyoung Yang,
M Nakao,
K Abe,
H Aihara,
Y Asano,
T Aushev,
S Bahinipati,
A M Bakich,
Y Ban,
I Bedny, [......],
M Watanabe,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Y Yuan,
L M Zhang,
Z P Zhang,
V Zhilich,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of the radiative decay B+-->K1(1270)(+) gamma using a data sample of 140 fb(-1) taken at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. We find the branching fraction to be B(B+-->K1(1270)(+)gamma)=(4.3+/-0.9(stat.)+/-0.9(syst.))x10(-5) with a significance of 7.3sigma. We find no significant signal for B+-->K1(1400)(+)gamma and set an upper limit B(B+-->K1(1400)(+)gamma)<1.5 x 10(-5) at the 90% confidence level. We also measure inclusive branching fractions for B+-->K+pi+pi-gamma and B0-->K0pi+pi-gamma in the mass range 1 GeV/c(2)<M(K+(0)pi+pi-)<2 GeV/c(2).
Physical Review Letters 03/2005; 94(11):111802. · 7.37 Impact Factor
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J Li,
Z P Zhang,
A J Schwartz,
K Abe,
H Aihara,
M Akatsu,
Y Asano,
T Aushev,
A M Bakich,
A Bay, [......], Heyoung Yang,
J Ying,
Y Yuan,
Y Yusa,
S L Zang,
C C Zhang,
J Zhang,
L M Zhang,
Z Zheng,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We have searched for mixing in the D(0)-D (0) system by measuring the decay-time distribution of D(0) --> K(+) pi(-) decays. The analysis uses 90 fb(-1) of data collected by the Belle detector at the KEKB e(+) e(-) collider. We fit the decay-time distribution for the mixing parameters x' and y' and also for the parameter R(D), which is the ratio of the rate for the doubly-Cabibbo-suppressed decay D(0)--> K+ pi(-) to that for the Cabibbo-favored decay D(0)--> K-pi(+). We do these fits both assuming CP conservation and allowing for CP violation. We use a frequentist method to obtain a 95% C.L. region in the x'(2) - y' plane. Assuming no mixing, we measure R(D) = (0.381 +/- 0.017(+0.008)(-0.016))%.
Physical Review Letters 02/2005; 94(7):071801. · 7.37 Impact Factor
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J Zhang,
K Abe,
T Abe,
H Aihara,
Y Asano,
V Aulchenko,
T Aushev,
T Aziz,
S Bahinipati,
A M Bakich, [......],
M Yamauchi, Heyoung Yang,
J Ying,
Y Yusa,
S L Zang,
C C Zhang,
Z P Zhang,
V Zhilich,
T Ziegler,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the branching fraction for the decay B+ --> rho(+) pi(0) based on a 140 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric e(+)e(-) collider. We measure the branching fraction B(B(+) --> rho(+)pi(0)) = (13.2 +/- 2.3(stat)(+1.4)(-1.9)(syst)) x 10(-6), and the CP-violating asymmetry A(CP)(B-/+ -->rho(-/+)pi(0))=0.06 +/- 0.17(stat)(+0.04)(-0.05)(syst).
Physical Review Letters 01/2005; 94(3):031801. · 7.37 Impact Factor
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S U Kataoka,
K Abe,
I Adachi,
H Aihara,
M Akatsu,
Y Asano,
T Aushev,
S Bahinipati,
A M Bakich,
A Bay, [......],
J Ying,
Y Yuan,
S L Zang,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
T Ziegler,
D Zontar
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of CP asymmetry parameters in the decay B0(B (0))-->J/psipi(0), which is governed by the b-->cc d transition. The analysis is based on a 140 fb(-1) data sample accumulated at the Upsilon(4S) resonance by the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson in the J/psipi(0) final state is fully reconstructed for events used in this analysis. The accompanying B meson flavor is identified by its decay products. From the distribution of proper-time intervals between the two B decays, we obtain the following CP-violating parameters: S(J/psipi(0))=-0.72+/-0.42(stat)+/-0.09(syst) and A(J/psipi(0))=-0.01+/-0.29(stat)+/-0.03(syst).
Physical Review Letters 12/2004; 93(26 Pt 1):261801. · 7.37 Impact Factor
