-
K-F Chen,
I Adachi,
H Aihara,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich,
V Balagura,
E Barberio,
A Bay, [......],
R Wedd,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C C Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the rare decays B --> h(*)nunu[over ], where h(*) stands for a light meson. A data sample of 535 x 10{6} BB[over ] pairs collected with the Belle detector at the KEKB e{+}e{-} collider is used. Signal candidates are required to have an accompanying B meson fully reconstructed in a hadronic mode and signal side particles consistent with a single h(*) meson. No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level. The limits on B{0} --> K{*0}nunu[over ] and B{+} --> K{+}nunu[over ] decays are more stringent than the previous constraints, while the first searches for B{0} --> K{0}nunu[over ], pi{0}nunu[over ], rho{0}nunu[over ], varphinunu[over ] and B{+} --> K{*+}nunu[over ], rho{+}nunu[over ] are reported.
Physical Review Letters 12/2007; 99(22):221802. · 7.37 Impact Factor
-
A Matyja,
M Rozanska,
I Adachi,
H Aihara,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich,
V Balagura,
E Barberio, [......],
C H Wang,
P Wang,
Y Watanabe,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Z P Zhang,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report an observation of the decay B{0}-->D{*-}tau{+}nu{tau} in a data sample containing 535x10{6} BB pairs collected with the Belle detector at the KEKB asymmetric-energy e{+}e{-} collider. We find a signal with a significance of 5.2sigma and measure the branching fraction B(B{0}-->D{*-}tau{+}nu{tau})=(2.02{-0.37}{+0.40}(stat)+/-0.37(syst))%. This is the first observation of an exclusive B decay with a b-->ctaunu{tau} transition.
Physical Review Letters 12/2007; 99(19):191807. · 7.37 Impact Factor
-
O Tajima,
M Hazumi,
I Adachi,
H Aihara,
V Aulchenko,
T Aushev,
A M Bakich,
E Barberio,
A Bay,
I Bedny, [......],
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C Z Yuan,
Y Yusa,
C C Zhang,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report the first search for CP-violating decays of the Upsilon(4S) using a data sample that contains 535 x 10(6) Upsilon(4S) mesons with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. A partial reconstruction technique is employed to enhance the signal sensitivity. No significant signals were observed. We obtain an upper limit of 4 x 10(-7) at the 90% confidence level for the branching fractions of the CP violating modes, Upsilon(4S)-->B(0)B(0)-->J/psiK(S)(0)+J/psi(eta(c))K(S)(0). Extrapolating the result, we find that an observation with 5sigma significance is expected with a 30 ab(-1) data sample, which is within the reach of a future super B factory.
Physical Review Letters 12/2007; 99(21):211601. · 7.37 Impact Factor
-
C Z Yuan,
C P Shen,
P Wang,
S McOnie,
I Adachi,
H Aihara,
V Aulchenko,
T Aushev,
S Bahinipati,
V Balagura, [......],
Y Watanabe,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
C C Zhang,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.
Physical Review Letters 11/2007; 99(18):182004. · 7.37 Impact Factor
-
A Go,
A Bay,
K Abe,
H Aihara,
D Anipko,
V Aulchenko,
T Aushev,
A M Bakich,
E Barberio,
K Belous, [......],
J Wicht,
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The neutral B meson pair produced at the Upsilon(4S) should exhibit a nonlocal correlation of the type discussed by Einstein, Podolsky, and Rosen. We measure this correlation using the time-dependent flavor asymmetry of semileptonic B(0) decays, which we compare with predictions from quantum mechanics and two local realistic models. The data are consistent with quantum mechanics, and inconsistent with the other models. Assuming that some B pairs disentangle to produce B(0) and B(0) with definite flavor, we find a decoherent fraction of 0.029 +/ -0.057, consistent with no decoherence.
Physical Review Letters 10/2007; 99(13):131802. · 7.37 Impact Factor
-
X L Wang,
C Z Yuan,
C P Shen,
P Wang,
I Adachi,
H Aihara,
K Arinstein,
T Aushev,
A M Bakich,
E Barberio, [......],
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C C Zhang,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The cross section for e+ e- --> pi+ pi- psi(2S) between threshold and sqrt[s]=5.5 GeV is measured using 673 fb(-1) of data on and off the Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the pi+ pi- psi(2S) invariant-mass distribution, one at 4361 +/- 9 +/- 9 MeV/c2 with a width of 74 +/- 15 +/- 10 MeV/c2, and another at 4664 +/- 11 +/- 5 MeV/c2 with a width of 48 +/- 15 +/- 3 MeV/c2, if the mass spectrum is parametrized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states.
Physical Review Letters 10/2007; 99(14):142002. · 7.37 Impact Factor
-
S-W Lin,
P Chang,
K Abe,
I Adachi,
H Aihara,
D Anipko,
V Aulchenko,
T Aushev,
S Bahinipati,
A M Bakich, [......],
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Y Yusa,
C C Zhang,
Z P Zhang,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report measurements of branching fractions for B --> K pi and B --> pi pi decays based on a data sample of 449 x 10(6) BB[over] pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We also measure the ratios of partial widths for B-->Kpi decays, namely R(c) identical with 2Gamma(B(+) --> K(+) pi(0))/Gamma(B(+) --> K(0) pi(+)) = 1.08+/-0.06+/-0.08 and R(n) identical with Gamma(B(0) --> K(+) pi(-))/2 Gamma(B(0) --> K(0) pi(0)) = 1.08+/-0.08+/-0.08, where the first and the second errors are statistical and systematic, respectively. These ratios are sensitive to enhanced electroweak penguin contributions from new physics; the new measurements are, however, consistent with standard model expectations.
Physical Review Letters 09/2007; 99(12):121601. · 7.37 Impact Factor
-
L M Zhang,
Z P Zhang,
I Adachi,
H Aihara,
V Aulchenko,
T Aushev,
A M Bakich,
V Balagura,
E Barberio,
A Bay, [......],
Y Watanabe,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C Z Yuan,
C C Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of D0-D(0) mixing parameters in D(0) --> K(s)(0) pi(+) pi(-) decays using a time-dependent Dalitz-plot analysis. We first assume CP conservation and subsequently allow for CP violation. The results are based on 540 fb(-1) of data accumulated with the Belle detector at the KEKB e(+)e(-) collider. Assuming negligible CP violation, we measure the mixing parameters x = (0.80 +/- 0.29(-0.07-0.14)(+0.09+0.10))% and y = (0.33+/-0.24(-0.12-0.08)(+0.08+0.06))%, where the errors are statistical, experimental systematic, and systematic due to the Dalitz decay model, respectively. Allowing for CP violation, we obtain the CP-violating parameters |q / p| = 0.86(-0.29-0.03)(+0.30+0.06) +/- 0.08 and arg(q/p) = (-14(-18-3-4)(+16+5+2)) degrees .
Physical Review Letters 09/2007; 99(13):131803. · 7.37 Impact Factor
-
K Belous,
M Shapkin,
A Sokolov,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
V Aulchenko,
T Aushev, [......],
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The mass of the tau lepton has been measured in the decay mode tau-->3pinutau using a pseudomass technique. The result obtained from 414 fb-1 of data collected with the Belle detector is Mtau=[1776.61+/-0.13(stat)+/-0.35(sys)] MeV/c2. The upper limit on the relative mass difference between positive and negative tau leptons is |Mtau+-Mtau-|/Mtau<2.8 x 10-4 at 90% confidence level.
Physical Review Letters 07/2007; 99(1):011801. · 7.37 Impact Factor
-
M Staric,
B Golob,
K Abe,
I Adachi,
H Aihara,
K Arinstein,
T Aushev,
T Aziz,
S Bahinipati,
A M Bakich, [......],
H Yamamoto,
Y Yamashita,
M Yamauchi,
C Z Yuan,
Y Yuan,
C C Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We observe evidence for D(0)-D(0) mixing by measuring the difference in the apparent lifetime when a D(0) meson decays to the CP eigenstates K(+)K(-) and pi(+)pi(-) and when it decays to the final state K(-)pi(+). We find the relative difference of the lifetimes y(CP) to be [1.31+/-0.32(stat)+/-0.25(syst)]%, 3.2 standard deviations from zero. We also search for a CP asymmetry between D(0) and D(0) decays; no evidence for CP violation is found. These results are based on 540 fb(-1) of data recorded by the Belle detector at the KEKB e(+)e(-) collider.
Physical Review Letters 06/2007; 98(21):211803. · 7.37 Impact Factor
-
S Fratina,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
T Aushev,
A M Bakich,
E Barberio,
A Bay, [......],
Y Watanabe,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C C Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report measurements of the branching fraction and CP violation parameters in B(0)-->D+ D- decays. The results are based on a data sample that contains 535 x 10(6) BB pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain [1.97+/-0.20(stat) +/- 0.20(syst)] x 10(-4) for the branching fraction of B0-->D+D-. The measured values of the CP violation parameters are S=-1.13+/-0.37+/-0.09, A=0.91+/-0.23+/-0.06, where the first error is statistical and the second is systematic. We find evidence of CP violation in B0-->D+D- at the 4.1sigma confidence level. While the value of S is consistent with expectations from other measurements, the value of the parameter A favors large direct CP violation at the 3.2sigma confidence level, in contradiction to standard model expectations.
Physical Review Letters 06/2007; 98(22):221802. · 7.37 Impact Factor
-
A Kusaka,
C C Wang,
H Ishino,
K Abe,
I Adachi,
H Aihara,
D Anipko,
V Aulchenko,
T Aushev,
A M Bakich, [......],
R Wedd,
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of CP asymmetry using a time-dependent Dalitz plot analysis of B0-->pi+pi-pi0 decays based on a 414 fb(-1) data sample containing 449 x 10(6) BB pairs. The data was collected on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider. Combining our analysis with information on charged B decay modes, we perform a full Dalitz and isospin analysis and obtain a constraint on the CKM angle phi2, 68 degrees < phi2 < 95 degrees as the 68.3% confidence interval for the phi2 solution consistent with the standard model (SM). A large SM-disfavored region also remains.
Physical Review Letters 06/2007; 98(22):221602. · 7.37 Impact Factor
-
R Mizuk,
K Abe,
I Adachi,
H Aihara,
D Anipko,
V Aulchenko,
T Aushev,
A M Bakich,
V Balagura,
E Barberio, [......],
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C Z Yuan,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report the results of several studies of the Lambda(c)(+)pi(+)pi(-)X final state in continuum e(+)e(-) annihilation data collected by the Belle detector. An analysis of angular distributions in Lambda(c)(2880)(+)-->Sigma(c)(2455)(0,++)pi(+,-) decays strongly favors a Lambda(c)(2880)(+) spin assignment of 5/2 over 3/2 or 1/2. We find evidence for Lambda(c)(2880)(+)-->Sigma(c)(2520)(0,++)pi(+,-) decay and measure the ratio of Lambda(c)(2880)(+) partial widths Gamma(Sigma(c)(2520)pi)/Gamma(Sigma(c)(2455)pi)=0.225+/-0.062+/-0.025. This value favors the Lambda(c)(2880)(+) spin-parity assignment of 5/2(+) over 5/2(-). We also report the first observation of Lambda(c)(2940)(+)-->Sigma(c)(2455)(0,++)pi(+,-) decay and measure Lambda(c)(2880)(+) and Lambda(c)(2940)(+) mass and width parameters. These studies are based on a 553 fb(-1) data sample collected at or near the Upsilon(4S) resonance at the KEKB collider.
Physical Review Letters 06/2007; 98(26):262001. · 7.37 Impact Factor
-
H Ishino,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
T Aushev,
A M Bakich,
E Barberio,
M Barbero, [......],
C-H Wu,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report a new measurement of the time-dependent CP-violating parameters in B(0)-->pi(+)pi(-) decays with 535 x 10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Upsilon(4S) resonance. We find 1464+/-65 B(0)-->pi(+)pi(-) events and measure the CP-violating parameters S(pipi)=-0.61+/-0.10(stat)+/-0.04(syst) and A(pipi)=+0.55+/-0.08(stat)+/-0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any S(pipi) value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2)=(97+/-11) degrees for the solution consistent with the standard model and exclude the range 11 degrees <phi(2)<79 degrees at the 95% confidence level.
Physical Review Letters 05/2007; 98(21):211801. · 7.37 Impact Factor
-
S-W Lin,
P Chang,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
V Aulchenko,
T Aushev,
T Aziz, [......],
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
C C Zhang,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: Using 449x10(6) BB[over ] pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider, we observe clear signals for B(+)-->K[over ](0)K(+) and B(0)-->K[over ](0)K(0) decays with 5.3sigma and 6.0sigma significance, respectively. We measure the branching fractions B(B(+)-->K[over ](0)K(+))=(1.22(-0.28-0.16)(+0.32+0.13))x10(-6) and B(B(0)-->K[over ](0)K(0))=(0.87(-0.20)(+0.25)+/-0.09)x10(-6), and partial-rate asymmetries A(CP)(B(+)-->K[over ](0)K(+))=0.13(-0.24)(+0.23)+/-0.02 and A(CP)(B(0)-->K[over ](0)K(0))=-0.58(-0.66)(+0.73)+/-0.04. From a simultaneous fit, we also obtain B(B(+)-->K(0)pi(+))=(22.8(-0.7)(+0.8)+/-1.3)x10(-6) and A(CP)(B(+)-->K(0)pi(+))=0.03+/-0.03+/-0.01. The first and second error in the branching fractions and the partial-rate asymmetries are statistical and systematic, respectively. No signal is observed for B(0)-->K(+)K(-) decays, and for this branching fraction, we set an upper limit of 4.1x10(-7) at the 90% confidence level.
Physical Review Letters 05/2007; 98(18):181804. · 7.37 Impact Factor
-
G Pakhlova,
K Abe,
I Adachi,
H Aihara,
D Anipko,
V Aulchenko,
T Aushev,
A M Bakich,
V Balagura,
E Barberio, [......],
Y Watanabe,
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
C C Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the exclusive e+e- -->D(*)+/-D*-/+ cross section as a function of center-of-mass energy near the D(*)+/-D*-/+ threshold with initial-state radiation. A partial reconstruction technique is used to increase the efficiency and to suppress background. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 547.8 fb(-1).
Physical Review Letters 03/2007; 98(9):092001. · 7.37 Impact Factor
-
M-C Chang,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
T Aushev,
A M Bakich,
E Barberio,
A Bay, [......],
E Won,
Q L Xie,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Y Yusa,
C C Zhang,
L M Zhang,
Z P Zhang,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of B(0)-->J/psieta decay. These results are obtained from a data sample that contains 449 x10(6) BB[over] pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We observe a signal with a significance of 8.1 sigma and obtain a branching fraction of (9.5+/-1.7(stat)+/-0.8(syst)) x 10(-6).
Physical Review Letters 03/2007; 98(13):131803. · 7.37 Impact Factor
-
O Tajima,
H Hayashii,
M Hazumi,
K Inami,
Y Iwasaki,
S Uehara,
K Abe,
I Adachi,
H Aihara,
D Anipko, [......],
J Wicht,
E Won,
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report results of a search for the invisible decay of the Upsilon(1S) via the Upsilon(3S)-->pi+ pi- Upsilon(1S) transition using a data sample of 2.9 fb-1 at the Upsilon(3S) resonance. The data were collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. No signal is found, and an upper limit for the branching fraction at the 90% confidence level is determined to be B(Upsilon(1S)-->invisible)<2.5 x 10(-3).
Physical Review Letters 03/2007; 98(13):132001. · 7.37 Impact Factor
-
K Abe,
I Adachi,
H Aihara,
K Arinstein,
Y Asano,
V Aulchenko,
T Aushev,
T Aziz,
A M Bakich,
V Balagura, [......],
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
J Ying,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
V Zhilich
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of a charmoniumlike state recoiling from the J/psi in the inclusive process e+e- -->J/psi+anything at a mass of (3.943+/-0.006+/-0.006) GeV/c{2}. We also observe the decay of this state into D*D[over ] and determine its intrinsic width to be less than 52 MeV/c{2} at the 90% C.L. These results are obtained from a 357 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 02/2007; 98(8):082001. · 7.37 Impact Factor
-
A Drutskoy,
K Abe,
I Adachi,
H Aihara,
D Anipko,
K Arinstein,
V Aulchenko,
T Aushev,
S Banerjee,
E Barberio, [......],
Q L Xie,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Y Yusa,
L M Zhang,
Z P Zhang,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The inclusive production of D(s), D(0), and J/psi mesons is studied using a 1.86 fb(-1) data sample collected on the Upsilon(5S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The number of bb events in this Upsilon(5S) data sample is determined. We measure the branching fractions B(Upsilon(5S)-->D(s)X)/2=(23.6+/-1.2+/-3.6)%, B(Upsilon(5S)-->D(0)X)/2=(53.8+/-2.0+/-3.4)%, and B(Upsilon(5S)-->J/psiX)/2=(1.030+/-0.080+/-0.067)%. From the D(s) and D(0) inclusive branching fractions the ratio f(s)=(18.0+/-1.3+/-3.2)% of B(s)(*)B(s)(*) to the total bb quark pair production at the Upsilon(5S) energy is obtained in a model-dependent way.
Physical Review Letters 02/2007; 98(5):052001. · 7.37 Impact Factor
