-
Belle Collaboration,
V. Bhardwaj,
K. Miyabayashi,
I. Adachi,
H. Aihara,
D. M. Asner,
V. Aulchenko,
T. Aushev,
T. Aziz,
A. M. Bakich, [......],
J. Yamaoka,
Y. Yamashita,
S. Yashchenko,
Y. Yook,
C. Z. Yuan,
C. C. Zhang,
Z. P. Zhang,
V. Zhilich,
V. Zhulanov,
A. Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report measurements of $B \to \chi_{c1} \gamma K$ and $\chi_{c2} \gamma K$
decays using $772 \times 10^{6}$ $B\bar{B}$ events collected at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy
$e^+e^-$ collider. Evidence of a new resonance in the $\chi_{c1} \gamma$ final
state is found with a statistical significance of $3.8 \sigma$. This state has
a mass of $3823.1 \pm 1.8 {(stat)} \pm 0.7 {(syst)}$ MeV/$c^2$, a value that is
consistent with theoretical expectations for the previously unseen $1^3 D_2$
$c\bar{c}$ meson. We find no other narrow resonance and set upper limits on the
branching fractions of the $X(3872) \to \chi_{c1} \gamma$ and $\chi_{c2}
\gamma$ decays.
04/2013;
-
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;
-
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;
-
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;
-
Belle Collaboration,
J. Stypula,
M. Rozanska,
I. Adachi,
K. Adamczyk,
H. Aihara,
D. M. Asner,
T. Aushev,
A. M. Bakich,
V. Bhardwaj, [......],
J. Wiechczynski,
K. M. Williams,
E. Won,
B. D. Yabsley,
H. Yamamoto,
Y. Yamashita,
Z. P. Zhang,
V. Zhilich,
V. Zhulanov,
A. Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report measurements of the decays B- -> Ds(*)+ K- l- nubar in a data
sample containing 657x10^6 BBbar pairs collected with the Belle detector at the
KEKB asymmetric-energy e+e- collider. We observe a signal with a significance
of 6 sigma for the combined Ds and Ds* modes and find the first evidence of the
B- -> Ds+ K- l- nubar decay with a significance of 3.4 sigma. We measure the
following branching fractions: BF(B- -> Ds+ K- l nubar) = (0.30 +/- 0.09(stat)
+0.11 -0.08(syst)) x 10^-3 and BF(B- -> Ds*+ K- l- nubar) = (0.59 +/-
0.12(stat) +/- 0.15(syst)) x 10^-3 and set an upper limit BF(B- -> Ds*+ K- l-
nubar) < 0.56 x 10^-3 at the 90% confidence level. We also present the first
measurement of the Ds+K- invariant mass distribution in these decays, which is
dominated by a prominent peak around 2.6 GeV/c^2.
07/2012;
-
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;
-
Belle Collaboration,
C. -L. Hsu,
P. Chang,
I. Adachi,
H. Aihara,
K. Arinstein,
D. M. Asner,
V. Aulchenko,
T. Aushev,
A. M. Bakich, [......],
P. Wang,
M. Watanabe,
Y. Watanabe,
K. M. Williams,
E. Won,
H. Yamamoto,
Y. Yamashita,
Z. P. Zhang,
V. Zhilich,
V. Zhulanov
[show abstract]
[hide abstract]
ABSTRACT: We report a search for $B^{0}$ decays into invisible final states using a
data sample of $657 \times 10^{6}$ $B\bar{B}$ pairs collected at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$
collider. The signal is identified by fully reconstructing a hadronic decay of
the accompanying $B$ meson and requiring no other particles in the event. No
significant signal is observed, and we obtain an upper limit of $1.3 \times
10^{-4}$ at the 90% confidence level for the branching fraction of invisible
$B^{0}$ decay.
06/2012;
-
Belle collaboration,
J. H. Kim,
M. Nakao,
I. Adachi,
K. Adamczyk,
H. Aihara,
D. M. Asner,
V. Aulchenko,
T. Aushev,
A. M. Bakich, [......],
M. Watanabe,
Y. Watanabe,
K. M. Williams,
E. Won,
H. Yamamoto,
Y. Yamashita,
Z. P. Zhang,
V. Zhilich,
V. Zhulanov,
A. Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report on a search for the charmless decays $B^{+} \to\phi\pi^{+}$ and
$B^{0} \to\phi \pi^{0}$ that are strongly suppressed in the Standard Model. The
analysis is based on a data sample of $657 \times 10^6$ $B \bar{B}$ pairs
collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB
asymmetric-energy $e^+ e^-$ collider. We find no significant signal and set
upper limits of $3.3 \times 10^{-7}$ for $B^{+} \to \phi \pi^{+}$ and $1.5
\times 10^{-7}$ for $B^0 \to \phi \pi^0$ at the 90% confidence level.
06/2012;
-
Y Sato,
H Yamamoto,
H Aihara,
D M Asner,
V Aulchenko,
T Aushev,
T Aziz,
A M Bakich,
V Bhardwaj,
B Bhuyan, [......],
Y Watanabe,
J Wicht,
E Won,
B D Yabsley,
Y Yamashita,
Y Yusa,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the CP-violation parameter sin2φ1 at the Υ(5S) resonance using a new tagging method, called "B-π tagging." In Υ(5S) decays containing a neutral B meson, a charged B, and a charged pion, the neutral B is reconstructed in the J/ψK(S)(0) CP-eigenstate decay channel. The initial flavor of the neutral B meson at the moment of the Υ(5S) decay is opposite to that of the charged B and may thus be inferred from the charge of the pion without reconstructing the charged B. From the asymmetry between B-π(+) and B-π(-) tagged J/ψK(S)(0) yields, we determine sin2φ1=0.57±0.58(stat)±0.06(syst). The results are based on 121 fb(-1) of data recorded by the Belle detector at the KEKB e(+)e(-) collider.
Physical Review Letters 04/2012; 108(17):171801. · 7.37 Impact Factor
-
I Adachi,
H Aihara,
D M Asner,
V Aulchenko,
T Aushev,
T Aziz,
A M Bakich,
A Bay,
V Bhardwaj,
B Bhuyan, [......],
E Won,
B D Yabsley,
H Yamamoto,
Y Yamashita,
M Yamauchi,
Y Yusa,
Z P Zhang,
V Zhilich,
A Zupanc,
O Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a precise measurement of the CP violation parameter sin2φ1 and the direct CP violation parameter A(f) using the final data sample of 772×10(6) BB[over ¯] pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is reconstructed in a J/ψK(S)(0), ψ(2S)K(S)(0), χ(c1)K(S)(0), or J/ψK(L)(0) CP eigenstate and its flavor is identified from the decay products of the accompanying B meson. From the distribution of proper-time intervals between the two B decays, we obtain the following CP violation parameters: sin2φ1=0.667±0.023(stat)±0.012(syst) and A(f)=0.006±0.016(stat)±0.012(syst).
Physical Review Letters 04/2012; 108(17):171802. · 7.37 Impact Factor
-
A Bondar,
A Garmash,
R Mizuk,
D Santel,
K Kinoshita,
I Adachi,
H Aihara,
K Arinstein,
D M Asner,
T Aushev, [......],
B D Yabsley,
Y Yamashita,
M Yamauchi,
C Z Yuan,
Y Yusa,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc,
O Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of two narrow structures in the mass spectra of the π(±)Υ(nS) (n=1, 2, 3) and π(±)h(b)(mP) (m=1, 2) pairs that are produced in association with a single charged pion in Υ(5S) decays. The measured masses and widths of the two structures averaged over the five final states are M(1)=(10,607.2±2.0) MeV/c2, Γ(1)=(18.4±2.4) MeV, and M(2)=(10,652.2±1.5) MeV/c2, Γ(2)=(11.5±2.2) MeV. The results are obtained with a 121.4 fb(-1) data sample collected with the Belle detector in the vicinity of the Υ(5S) resonance at the KEKB asymmetric-energy e+ e- collider.
Physical Review Letters 03/2012; 108(12):122001. · 7.37 Impact Factor
-
Belle Collaboration,
I. Adachi,
H. Aihara,
D. M. Asner,
V. Aulchenko,
T. Aushev,
T. Aziz,
A. M. Bakich,
A. Bay,
V. Bhardwaj, [......],
E. Won,
B. D. Yabsley,
H. Yamamoto,
Y. Yamashita,
M. Yamauchi,
Y. Yusa,
Z. P. Zhang,
V. Zhilich,
A. Zupanc,
O. Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We present a precise measurement of the CP violation parameter sin2phi_1 and
the direct CP violation parameter A_f using the final data sample of 772x10^6
B\bar B pairs collected at the Upsilon(4S) resonance with the Belle detector at
the KEKB asymmetric-energy e+e- collider. One neutral B meson is reconstructed
in a J/psi K0S, psi(2S) K0S, chi_c1 K0S or J/psi K0L CP-eigenstate and its
flavor is identified from the decay products of the accompanying B meson. From
the distribution of proper time intervals between the two B decays, we obtain
the following CP violation parameters:
sin2phi_1=0.667+-0.023(stat)+-0.012(syst) and
A_f=0.006+-0.016(stat)+-0.012(syst).
01/2012;
-
I Adachi,
H Aihara,
K Arinstein,
D M Asner,
T Aushev,
T Aziz,
A M Bakich,
E Barberio,
K Belous,
V Bhardwaj, [......],
C H Wang,
X L Wang,
Y Watanabe,
J Wicht,
E Won,
B D Yabsley,
Y Yamashita,
C Z Yuan,
V Zhilich,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report the first observations of the spin-singlet bottomonium states h(b)(1P) and h(b)(2P). The states are produced in the reaction e(+)e(-)→h(b)(nP)π(+)π(-) using a 121.4 fb(-1) data sample collected at energies near the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We determine M[h(b)(1P)]=(9898.2(-1.0-1.1)(+1.1+1.0)) MeV/c(2) and M[h(b)(2P)]=(10,259.8±0.6(-1.0)(+1.4)) MeV/c(2), which correspond to P-wave hyperfine splittings ΔM(HF)=(+1.7±1.5) and (+0.5(-1.2)(+1.6)) MeV/c(2), respectively. The significances of the h(b)(1P) and h(b)(2P) are 5.5σ and 11.2σ, respectively. We find that the production of the h(b)(1P) and h(b)(2P) is not suppressed relative to the production of the Υ(1S), Υ(2S), and Υ(3S).
Physical Review Letters 01/2012; 108(3):032001. · 7.37 Impact Factor
-
Belle Collaboration,
Y. Sato,
H. Yamamoto,
H. Aihara,
D. M. Asner,
V. Aulchenko,
T. Aushev,
T. Aziz,
A. M. Bakich,
V. Bhardwaj, [......],
Y. Watanabe,
J. Wicht,
E. Won,
B. D. Yabsley,
Y. Yamashita,
Y. Yusa,
Z. P. Zhang,
V. Zhilich,
V. Zhulanov,
A. Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the CP-violation parameter sin2$\phi_1$ at the
$\Upsilon(5S)$ resonance using a new tagging method, called "$B$-$\pi$
tagging." In $\Upsilon(5S)$ decays containing a neutral $B$ meson, a charged
$B$, and a charged pion, the neutral $B$ is reconstructed in the $J/\psi K_S^0$
CP-eigenstate decay channel. The initial flavor of the neutral $B$ meson at the
moment of the $\Upsilon(5S)$ decay is opposite to that of the charged $B$ and
may thus be inferred from the charge of the pion without reconstructing the
charged $B$. From the asymmetry between $B$-$\pi^+$ and $B$-$\pi^-$ tagged
$J/\psi K_S^0$ yields, we determine sin2$\phi_1$ = 0.57 $\pm$ 0.58(stat) $\pm$
0.06(syst). The results are based on 121 fb$^{-1}$ of data recorded by the
Belle detector at the KEKB $e^+ e^-$ collider.
01/2012;
-
E Won,
B R Ko,
I Adachi,
H Aihara,
K Arinstein,
D M Asner,
T Aushev,
A M Bakich,
E Barberio,
A Bay, [......],
Y Watanabe,
K M Williams,
B D Yabsley,
Y Yamashita,
M Yamauchi,
Z P Zhang,
V Zhilich,
V Zhulanov,
A Zupanc,
O Zyukova
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of the doubly Cabibbo-suppressed decays D(+)→K(+)η((')) using a 791 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The ratio of the branching fractions of doubly Cabibbo-suppressed relative to singly Cabibbo-suppressed D(+)→π(+)η((')) decays are B(D(+)→K(+)η)/B(D(+)→π(+)η)=(3.06±0.43±0.14)% and B(D(+)→K(+)η')/B(D(+)→π(+)η')=(3.77±0.39±0.10)%. From these, we find that the relative final-state phase difference between the tree and annihilation amplitudes in D(+) decays, δ(TA), is (72±9)° or (288±9)°. We also report the most precise measurements of CP asymmetries to date: A(CP)(D(+)→π(+)η)=(+1.74±1.13±0.19)% and A(CP)(D(+)→π(+)η')=(-0.12±1.12±0.17)%.
Physical Review Letters 11/2011; 107(22):221801. · 7.37 Impact Factor
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P Chen,
M. -Z. Wang,
I. Adachi,
H. Aihara,
D. M. Asner,
V. Aulchenko,
T. Aushev,
A. M. Bakich,
E Barberio,
K. Belous, [......],
K E Varvell,
C H Wang,
X L Wang,
Y Watanabe,
K M Williams,
E. Won,
B. D. Yabsley,
Y Yamashita,
M Yamauchi,
Z P Zhang
[show abstract]
[hide abstract]
ABSTRACT: We study B- meson decays to pbar Lambda D(*)0 final states using a sample of
657 * 10^6 B Bbar events collected at the Upsilon(4S) resonance with the Belle
detector at the KEKB asymmetric-energy e+ e- collider. The observed branching
fraction for B- to pbar Lambda D0 is (1.43^ +0.28_-0.25 +- 0.18)*10^-5. with a
significance of 8.1 standard deviations, where the uncertainties are
statistical and systematic, respectively. Most of the signal events have the
pbarLambda mass peaking near threshold. No significant signal is observed for
B- to pbar Lambda D*0 and the corresponding upper limit on the branching
fraction is 4.8 * 10^-5 at the 90% confidence level.
08/2011;
-
A Vossen,
R Seidl,
I Adachi,
H Aihara,
T Aushev,
V Balagura,
W Bartel,
M Bischofberger,
A Bondar,
M Bračko, [......],
C H Wang,
M-Z Wang,
P Wang,
Y Watanabe,
E Won,
B D Yabsley,
Y Yamashita,
V Zhilich,
P Zhou,
V Zhulanov
[show abstract]
[hide abstract]
ABSTRACT: The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.
Physical Review Letters 08/2011; 107(7):072004. · 7.37 Impact Factor
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Y Horii,
K Trabelsi,
H Yamamoto,
I Adachi,
H Aihara,
K Arinstein,
V Aulchenko,
T Aushev,
V Balagura,
E Barberio, [......],
M Watanabe,
Y Watanabe,
J Wicht,
E Won,
B D Yabsley,
Y Yamashita,
D Zander,
Z P Zhang,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The suppressed decay chain B(-)→DK(-), D→K(+)π(-), where D indicates a D(¯)(0) or D(0) state, provides important information on the CP-violating angle ϕ(3). We measure the ratio R(DK) of the decay rates to the favored mode B(-)→DK(-), D→K(-)π(+) to be R(DK)=[1.63(-0.41)(+0.44)(stat)(-0.13)(+0.07)(syst)]×10(-2), which indicates the first evidence of the signal with a significance of 4.1σ. We also measure the asymmetry A(DK) between the charge-conjugate decays to be A(DK)=-0.39(-0.28)(+0.26)(stat)(-0.03)(+0.04)(syst). The results are based on the full 772×10(6) BB(¯) pair data sample collected at the Υ(4S) resonance with the Belle detector.
Physical Review Letters 06/2011; 106(23):231803. · 7.37 Impact Factor
-
Belle Collaboration,
Y Horii,
K. Trabelsi,
H Yamamoto,
I. Adachi,
H. Aihara,
K. Arinstein,
V. Aulchenko,
T. Aushev,
V. Balagura, [......],
M Watanabe,
Y Watanabe,
J. Wicht,
E. Won,
B. D. Yabsley,
Y Yamashita,
D. Zander,
Z P Zhang,
V. Zhulanov,
A. Zupanc
[show abstract]
[hide abstract]
ABSTRACT: The suppressed decay chain B- -> DK-, D -> K+pi-, where D indicates a anti-D0
or D0 state, provides important information on the CP-violating angle phi_3. We
measure the ratio R_{DK} of the decay rates to the favored mode B- -> DK-, D ->
K-pi+ to be R_{DK} = [1.63^{+0.44}_{-0.41}(stat)^{+0.07}_{-0.13}(syst)] x
10^{-2}, which indicates the first evidence of the signal with a significance
of 4.1sigma. We also measure the asymmetry A_{DK} between the charge-conjugate
decays to be A_{DK} = -0.39^{+0.26}_{-0.28}(stat)^{+0.04}_{-0.03}(syst). The
results are based on the full 772 x 10^6 B anti-B pair data sample collected at
the Upsilon(4S) resonance with the Belle detector.
03/2011;
-
J Li,
H Aihara,
K Arinstein,
V Aulchenko,
T Aushev,
T Aziz,
A M Bakich,
V Balagura,
E Barberio,
K Belous, [......],
E Won,
B D Yabsley,
Y Yamashita,
D Zander,
C C Zhang,
Z P Zhang,
V Zhilich,
P Zhou,
V Zhulanov,
A Zupanc
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of B(s)⁰→J/ψf₀(980) and evidence for B(s)⁰→J/ψf₀(1370), which are CP eigenstate decay modes. These results are obtained from 121.4 fb⁻¹ of data collected at the Υ(5S) resonance with the Belle detector at the KEKB e(+)e⁻ collider. We measure the branching fractions B(B(s)⁰→J/ψf₀(980); f₀(980)→π(+)π⁻)=(1.16(-0.19)(+0.31)(stat)(-0.17)(+0.15)(syst)(-0.18)(+0.26)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 8.4σ, and B(B(s)⁰→J/ψf₀(1370); f₀(1370)→π(+)π⁻)=(0.34(-0.14)(+0.11)(stat)(-0.02)(+0.03)(syst)(-0.05)(+0.08)(N(B(s)((*))B(s)((*)))))×10⁻⁴ with a significance of 4.2σ. The last error listed is due to uncertainty in the number of produced B(s)((*))B(s)((*)) pairs.
Physical Review Letters 03/2011; 106(12):121802. · 7.37 Impact Factor
