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Belle Collaboration,
I. Adachi,
K. Adamczyk,
H. Aihara,
K. Arinstein,
Y. Arita,
D. M. Asner,
T. Aso,
V. Aulchenko,
T. Aushev, [......],
L. M. Zhang,
Z. P. Zhang,
L. Zhao,
V. Zhilich,
P. Zhou,
V. Zhulanov,
T. Zivko,
A. Zupanc,
N. Zwahlen,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the time-dependent CP violation parameters in B0
-> pi+ pi- decays. The results are obtained from the final data sample
containing 772 million BBbar pairs collected at the Upsilon(4S) resonance with
the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the
CP violation parameters Acp = +0.33 +/- 0.06 (stat) +/- 0.03 (syst) and Scp =
-0.64 +/- 0.08 (stat) +/- 0.03 (syst), where Acp and Scp represent direct and
mixing-induced CP violation, respectively. From an isospin analysis including
results from other Belle measurements, we rule out 23.8 < phi2 < 66.8 degrees
at the 1 sigma level.
02/2013;
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I. Adachi,
K. Adamczyk,
H. Aihara,
K. Arinstein,
Y. Arita,
D. M. Asner,
T. Aso,
V. Aulchenko,
T. Aushev,
T. Aziz, [......],
L. M. Zhang,
Z. P. Zhang,
L. Zhao,
V. Zhilich,
P. Zhou,
V. Zhulanov,
T. Zivko,
A. Zupanc,
N. Zwahlen,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a study of the branching fraction of the decay B^0 -> rho^0 rho^0
and the fraction of longitudinally polarized \rho^0 mesons in this decay. The
results are obtained from the final data sample containing $772 \times 10^{6}$
$B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle
detector at the KEKB asymmetric-energy e^+e^- collider. We find $166 \pm 59$
B^0 -> rho^0 rho^0 events, corresponding to a branching fraction of ${\cal
B}(B^0 -> rho^0 rho^0) = (1.02\pm 0.30 (\rm stat) \pm 0.22 (\rm syst))\times
10^{-6} $ with a longitudinally polarization fraction $f_L =
0.21^{+0.18}_{-0.22} (\rm stat) \pm 0.11 (\rm syst)$. The branching fraction's
upper limit is ${\cal B}(B^0 -> rho^0 rho^0) < 1.5 \times 10^{-6}$ at 90%
confidence level. We use the longitudinal polarization fraction to determine
the Cabibbo-Kobayashi-Maskawa matrix angle $\phi_2 = (91.0 \pm 7.2)^{\circ}$
through an isospin analysis in the $B\to\rho\rho$ system. We furthermore obtain
${\cal B}(B^0 -> rho^0 f_0) \times {\cal B}(f_0 -> \pi^+\pi^-) = (0.86 \pm 0.27
(\rm stat) \pm 0.15 (\rm syst))\times 10^{-6}$, corresponding to $149 \pm 49$
$B^0 -> rho^0 f_0$ events with a significance of 3.0 standard deviations and
upper limits at 90% confidence level on the (product) branching fractions for
possible decays with the same final state, ${\cal B}(B^0 -> pi^+\pi^-pi^+\pi^-)
< 11.7 \times 10^{-6} $, ${\cal B}(B^0 -> rho^0 pi^+\pi^-) < 12.2 \times
10^{-6}$, ${\cal B}(B^0 -> f_0 pi^+\pi^-) \times {\cal B}(f_0->\pi^+\pi^-) <
3.1 \times 10^{-6}$ and ${\cal B}(B^0 -> f_0 f_0) \times {\cal
B}(f_0->\pi^+\pi^-)^{2} < 0.2 \times 10^{-6}$.
12/2012;
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I. Adachi,
K. Adamczyk,
H. Aihara,
K. Arinstein,
Y. Arita,
D. M. Asner,
T. Aso,
V. Aulchenko,
T. Aushev,
T. Aziz, [......],
L. M. Zhang,
Z. P. Zhang,
L. Zhao,
V. Zhilich,
P. Zhou,
V. Zhulanov,
T. Zivko,
A. Zupanc,
N. Zwahlen,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We report preliminary results on the analysis of the three-body Y(10860)=> B
barB pi, Y(10860) => (B barB* + c.c.) pi and Y(10860)=> B* barB* pi decays
including an observation of the Y(10860)=> Zb(10610)+- pi-+ => [B barB*+c.c]+-
pi-+ and Y(10860)=> Zb(10650)+- pi-+ => [B* barB*]+- pi-+ decays as
intermediate channels. We measure branching fractions of the three-body decays
to be Br(Y(10860)=> [B barB*+c.c.]+- pi-+)=(28.3+-2.9+-4.6)x10^{-3} and
Br(Y(10860)=> [B* barB*]+- pi-+)=(14.1+-1.9+-2.4)x10^{-3} and set 90% C.L.
upper limit Br(Y(10860)=> [B barB]+- pi-+)<4.0x10^{-3}. We also report results
on the amplitude analysis of the three-body Y(10860)=>Y(nS)pi+pi-, n=1,2,3
decays and the analysis of the internal structure of the three-body
Y(10860)=>hb(mP)pi+pi-, m=1,2 decays. The results are based on a 121.4 1/fb
data sample collected with the Belle detector at a center-of-mass energy near
the Y(10860).
09/2012;
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I. Adachi,
K. Adamczyk,
H. Aihara,
K. Arinstein,
Y. Arita,
D. M. Asner,
T. Aso,
V. Aulchenko,
T. Aushev,
T. Aziz, [......],
L. M. Zhang,
Z. P. Zhang,
L. Zhao,
V. Zhilich,
P. Zhou,
V. Zhulanov,
T. Zivko,
A. Zupanc,
N. Zwahlen,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of Y(5S) -> Y(1,2S) pi0 pi0 decays. Evidence
for the Zb0(10610) with 4.9sigma significance is found in a Dalitz plot
analysis of Y(5S) -> Y(2S) pi0 pi0 decays. The results are obtained with a
121.4 fb^-1 data sample collected with the Belle detector at the Y(5S)
resonance at the KEKB asymmetric-energy e+e- collider.
07/2012;
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T Abe,
I. Adachi,
K. Adamczyk,
S Ahn,
H. Aihara,
K. Akai,
M. Aloi,
L. Andricek,
K Aoki,
Y Arai, [......],
Z P Zhang,
J Zhao,
L Zhao,
Z Zhao,
V. Zhilich,
P Zhou,
V. Zhulanov,
T. Zivko,
A. Zupanc,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector. Comment: Edited by: Z. Dole\v{z}al and S. Uno
11/2010;
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L Widhalm,
I Adachi,
H Aihara,
T Aushev,
A M Bakich,
V Balagura,
E Barberio,
A Bay,
I Bedny,
V Bhardwaj, [......],
Y Watanabe,
R Wedd,
E Won,
B D Yabsley,
H Yamamoto,
Y Yamashita,
Z P Zhang,
V Zhilich,
A Zupanc,
O Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the branching fraction B(D{s}{+}-->mu{+}nu{mu}) using a 548 fb{-1} data sample collected by the Belle experiment at the KEKB e{+}e{-} collider. The D{s} momentum is determined by reconstruction of the system recoiling against DKgammaX in events of the type e{+}e{-}-->D{s}{*}DKX, D{s}{*}-->D{s}gamma, where X represents additional pions or photons from fragmentation. This full-reconstruction method provides high resolution in the neutrino momentum and thus good background separation, equivalent to that achieved by experiments at the tau-charm factories. We obtain the branching fraction B(D{s}{+}-->mu{+}nu{mu})=[6.44+/-0.76(stat)+/-0.57(syst)]x10{-3}, implying a D{s} decay constant of f{D{s}}=[275+/-16(stat)+/-12(syst)] MeV.
Physical Review Letters 06/2008; 100(24):241801. · 7.37 Impact Factor
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L Widhalm,
K Abe,
I Adachi,
H Aihara,
K Arinstein,
Y Asano,
T Aushev,
A M Bakich,
V Balagura,
E Barberio, [......],
Y Watanabe,
E Won,
B D Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
J Ying,
L M Zhang,
Z P Zhang,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: Using a 282 fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider, we study D0 decays to K-l+nu and pi-l+nu final states. The D0 flavor and momentum are tagged through a full reconstruction of the recoiling charm meson and additional mesons from fragmentation. The reconstruction method provides very good resolution in neutrino momentum and in q2=(pl+pnu)2. Normalizing to the total number of D0 tags, we measure the absolute branching fractions to be B(D0-->Klnu)=(3.45+/-0.07stat+/-0.20syst)% and B(D0-->pilnu)=(0.255+/-0.019stat+/-0.016syst)% and the semileptonic form factors (within the modified pole model) f+K(0)=0.695+/-0.007stat+/-0.022syst and f+pi(0)=0.624+/-0.020stat+/-0.030syst.
Physical Review Letters 08/2006; 97(6):061804. · 7.37 Impact Factor
-
Y Chao,
P Chang,
K Abe,
N Abe,
I Adachi,
H Aihara,
K Akai,
M Akatsu,
M Akemoto,
Y Asano, [......],
S L Zang,
C C Zhang,
J Zhang,
L M Zhang,
Z P Zhang,
Y Zheng,
V Zhilich,
T Ziegler,
D Zontar,
D Zürcher
[show abstract]
[hide abstract]
ABSTRACT: We report evidence for direct CP violation in the decay B0-->K+pi(-) with 253 fb(-1) of data collected with the Belle detector at the KEKB e(+)e(-) collider. Using 275x10(6) BB pairs we observe a B-->K+/-pi(-/+) signal with 2140+/-53 events. The measured CP violating asymmetry is A(CP)(K+pi(-))=-0.101+/-0.025(stat)+/-0.005(syst), corresponding to a significance of 3.9sigma including systematics. We also search for CP violation in the decays B+-->K+pi(0) and B+-->pi(+)pi(0). The measured CP violating asymmetries are A(CP)(K+pi(0))=0.04+/-0.05(stat)+/-0.02(syst) and A(CP)(pi(+)pi(0))=-0.02+/-0.10(stat)+/-0.01(syst), corresponding to the intervals -0.05<A(CP)(K+pi(0))<0.13 and -0.18<A(CP)(pi(+)pi(0))<0.14 at 90% confidence level.
Physical Review Letters 11/2004; 93(19):191802. · 7.37 Impact Factor
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J.R. Batley,
A.J. Culling,
G. Kalmus,
C. Lazzeroni,
D.J. Munday,
M.W. Slater,
S.A. Wotton,
R. Arcidiacono,
G. Bocquet,
N. Cabibbo, [......],
N. Cartiglia,
M. Clemencic,
S. Goy Lopez,
F. Marchetto,
H. Dibon,
M. Jeitler,
M. Markytan,
I. Mikulec,
G. Neuhofer, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: A search for direct CP-violation in K±→π±π0π0 decay based on 47.14 million events has been performed by the NA48/2 experiment at the CERN SPS. The asymmetry in the Dalitz plot linear slopes Ag=(g+−g−)/(g++g−) is measured to be Ag=(1.8±2.6)×10−4. The design of the experiment and the method of analysis provide good control of instrumental charge asymmetries in this measurement. The precision of the result is limited by statistics and is almost one order of magnitude better than that of previous measurements by other experiments.
Physics Letters B.
-
A. Lai,
D. Marras,
J.R. Batley,
A.J. Bevan,
R.S. Dosanjh,
T.J. Gershon,
G.E. Kalmus,
C. Lazzeroni,
D.J. Munday,
E. Olaiya, [......],
M. Szleper,
W. Wislicki,
S. Wronka,
H. Dibon,
M. Jeitler,
M. Markytan,
G. Neuhofer,
M. Pernicka,
A. Taurok, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: New measurements of the η and K0 masses have been performed using decays to 3π0 with the NA48 detector at the CERN SPS. Using symmetric decays to reduce systematic effects, the results M(η)=547.843±0.051 MeV/c2 and M(K0)=497.625±0.031 MeV/c2 were obtained.
Physics Letters B.
-
T. Uglov,
K Abe,
T Abe,
H. Aihara,
M. Akatsu,
Y Asano,
T Aso,
V. Aulchenko,
A. Bakich,
Y Ban, [......],
A Yamaguchi,
Y Yamashita,
M Yamauchi,
Heyoung Yang,
J. Ying,
Y. Yusa,
C Zhang,
V. Zhilich,
D. Žontar,
Belle Collaboration
-
L Widhalm,
I. Adachi,
H. Aihara,
T. Aushev,
A. M. Bakich,
V. Balagura,
E Barberio,
A. Bay,
I. Bedny,
V. Bhardwaj, [......],
Y Watanabe,
R. Wedd,
E. Won,
B. D. Yabsley,
H Yamamoto,
Y Yamashita,
Z P Zhang,
V. Zhilich,
A. Zupanc,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the branching fraction B(Ds+→μ+νμ ) using a 548fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider. The Ds momentum is determined by reconstruction of the system recoiling against DKγX in events of the type e+e-→Ds*DKX, Ds*→Dsγ, where X represents additional pions or photons from fragmentation. This full-reconstruction method provides high resolution in the neutrino momentum and thus good background separation, equivalent to that achieved by experiments at the tau-charm factories. We obtain the branching fraction B(Ds+→μ+νμ)=[6.44±0.76(stat)±0.57(syst)] ×10-3, implying a Ds decay constant of fDs=[275±16(stat) ±12(syst)]MeV. © 2008 The American Physical Society.
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L Widhalm,
K Abe,
I. Adachi,
H. Aihara,
K. Arinstein,
Y Asano,
T. Aushev,
A. Bakich,
V. Balagura,
E Barberio, [......],
E. Won,
B. Yabsley,
A Yamaguchi,
Y Yamashita,
M Yamauchi,
J. Ying,
L Zhang,
Z Zhang,
D. Zürcher,
Belle Collaboration
-
A. Lai,
D. Marras,
A. Bevan,
R.S. Dosanjh,
T.J. Gershon,
B. Hay,
G.E. Kalmus,
C. Lazzeroni,
D.J. Munday,
E. Olaiya, [......],
S. Wronka,
H. Dibon,
G. Fischer,
M. Jeitler,
M. Markytan,
I. Mikulec,
G. Neuhofer,
M. Pernicka,
A. Taurok, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: In data taken with the NA48 experiment at the CERN SPS in 1999, 730 candidates of the weak radiative hyperon decay Ξ0→Λγ have been found with an estimated background of 58±8 events. From these events the Ξ0→Λγ decay asymmetry has been determined to α(Ξ0→Λγ)=−0.78±0.18stat±0.06syst, which is the first evidence of a decay asymmetry in Ξ0→Λγ. The branching fraction of the decay has been measured to be Br(Ξ0→Λγ)=(1.16±0.05stat±0.06syst)×10−3.
Physics Letters B.
-
J.R. Batley,
A.J. Culling,
G. Kalmus,
C. Lazzeroni,
D.J. Munday,
M.W. Slater,
S.A. Wotton,
R. Arcidiacono,
G. Bocquet,
N. Cabibbo, [......],
N. Cartiglia,
M. Clemencic,
S. Goy Lopez,
F. Marchetto,
H. Dibon,
M. Jeitler,
M. Markytan,
I. Mikulec,
G. Neuhofer, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the direct CP violation asymmetry parameter Ag in charged kaon decays K±→π±π+π− by the NA48/2 experiment at the CERN SPS. The experiment has been designed not to be limited by systematics in the asymmetry measurement. Using 1.67×109 such decays collected during the 2003 run, the charge asymmetry in the Dalitz plot linear slope parameter g has been measured to be Ag=(1.7±2.9)×10−4. The precision of the result is limited by the statistics used.
Physics Letters B.
-
A. Lai,
D. Marras,
J.R. Batley,
R.S. Dosanjh,
T.J. Gershon,
G.E. Kalmus,
C. Lazzeroni,
D.J. Munday,
E. Olaiya,
M.A. Parker, [......],
M. Szleper,
W. Wislicki,
S. Wronka,
H. Dibon,
M. Jeitler,
M. Markytan,
G. Neuhofer,
M. Pernicka,
A. Taurok, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: Using data taken during the year 2000 with the NA48 detector at the CERN SPS, a search for the CP violating decay KS→3π0 has been performed. From a fit to the lifetime distribution of about 4.9 million reconstructed decays, the CP violating amplitude η000=A(KS→3π0)/A(KL→3π0) has been found to be Re(η000)=−0.002±0.011±0.015 and Im(η000)=−0.003±0.013±0.017. This corresponds to an upper limit on the branching fraction of Br(KS→3π0)<7.4×10−7 at 90% confidence level. The result is used to improve knowledge of Re(ε) and the CPT violating quantity Im(δ) via the Bell–Steinberger relation.
Physics Letters B.
-
J.R. Batley,
A.J. Culling,
G. Kalmus,
C. Lazzeroni,
D.J. Munday,
M.W. Slater,
S.A. Wotton,
R. Arcidiacono,
G. Bocquet,
N. Cabibbo, [......],
F. Marchetto,
S. Bifani,
M. Clemencic,
S. Goy Lopez,
H. Dibon,
M. Jeitler,
M. Markytan,
I. Mikulec,
G. Neuhofer, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: As first observed by the NA48/2 experiment at the CERN SPS, the π0π0 invariant mass (M00) distribution from K±→π±π0π0 decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the ππ scattering lengths in the isospin I=0 and I=2 states, a0 and a2, respectively, has been recently reported. In the present work the Dalitz plot of this decay is fitted to a new empirical parameterization suitable for practical purposes, such as Monte Carlo simulations of K±→π±π0π0 decays.
Physics Letters B.
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J.R. Batley,
G.E. Kalmus,
C. Lazzeroni,
D.J. Munday,
M. Patel,
M.W. Slater,
S.A. Wotton,
R. Arcidiacono,
G. Bocquet,
A. Ceccucci, [......],
N. Cartiglia,
M. Clemencic,
E. Menichetti,
N. Pastrone,
W. Wislicki,
H. Dibon,
M. Jeitler,
M. Markytan,
G. Neuhofer, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: The decay rate of KS→πeν relative to the rate of KL→πeν has been measured by the NA48 Collaboration in a neutral kaon beam originating from 400 GeV proton-Be interactions at the CERN SPS. The result is 0.993±stat0.026±syst0.022, compatible with 1 in agreement with the Standard Model prediction at tree level. It implies BR(KS→πeν)=(7.05±stat0.18±syst0.16)×10−4.
Physics Letters B.
-
T. Uglov,
K Abe,
T Abe,
H. Aihara,
M. Akatsu,
Y Asano,
T Aso,
V. Aulchenko,
A. M. Bakich,
Y Ban, [......],
M Iwasaki,
Y Iwasaki,
J H Kang,
J. S. Kang Kapusta,
N Katayama,
H Kawai,
T Kawasaki,
H. Kichimi,
S Kumar,
H J Kim
-
A. Lai,
D. Marras,
A. Bevan,
R.S. Dosanjh,
T.J. Gershon,
B. Hay,
G.E. Kalmus,
C. Lazzeroni,
D.J. Munday,
M.D. Needham, [......],
W. Wislicki,
S. Wronka,
H. Dibon,
G. Fischer,
M. Jeitler,
M. Markytan,
G. Neuhofer,
M. Pernicka,
A. Taurok, L. Widhalm
[show abstract]
[hide abstract]
ABSTRACT: The decay rate of KL→π0γγ has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL→π0γγ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be (1.36±0.03(stat)±0.03(syst)±0.03(norm))×10−6 and the vector coupling constant av=−0.46±0.03(stat)±0.04(syst). This result suggests that the CP-violation effects are dominating in the KL→π0e+e− decay. An upper limit for the KL→π0γγ decay rate in the two photon mass region mγγ<mπ0 is also given.
Physics Letters B.
