1,202 research outputs found
Search for CP violation in tau -> K^0_S pi nu_tau decays at Belle
We report on a search for CP violation in tau -> K^0_S pi nu_tau decays using
a data sample of 699 fb^{-1} collected in the Belle experiment at the KEKB
electron-positron asymmetric-energy collider. The CP asymmetry is measured in
four bins of the invariant mass of the K^0_S pi system and found to be
compatible with zero with a precision of O(10^{-3}) in each mass bin. Limits
for the CP violation parameter Im(eta_S) are given at a 90 % confidence level.
These limits are |Im(eta_S)|<0.026 or better, depending on the parameterization
used to describe the hadronic form factors and improve upon previous limits by
one order of magnitude
High resolution mapping of a novel late blight resistance gene Rpi-avll, from the wild Bolivian species Solanum avilesii
Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance (R) genes to late blight (Phytophthora infestans). Here, we focus on an R gene present in the diploid Bolivian species S. avilesii. The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1, which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl
Measurement of the decay and determination of
We present a measurement of the charmless semileptonic decay
using a data sample containing 657
events collected with the Belle detector at the KEKB
asymmetric-energy collider operating near the
resonance. We determine the total branching fraction of the decay,
. We also report a new precise measurement
of the differential decay rate, and extract the Cabibbo-Kobayashi-Maskawa
matrix element using model-independent and -dependent approaches.
From a simultaneous fit to the measured differential decay rate and lattice QCD
results, we obtain , where the error
includes both statistical and systematic uncertainties.Comment: 8 pages, 3 figures, Submitted to PRD(RC
Search for CP Violation in D Meson Decays to phi pi+
We search for CP violation in Cabibbo-suppressed charged D meson decays by
measuring the difference between the CP violating asymmetries for the
Cabibbo-suppressed decays D+ -> K+K-pi+ and the Cabibbo-favored decays Ds ->
K+K-pi+ in the K+K- mass region of the phi resonance. Using 955/fb of data
collected with the Belle detector we obtain A_CP(D+ -> phi pi+) = (+0.51 +-
0.28 +- 0.05)%. The measurement improves the sensitivity of previous searches
by more than a factor of five. We find no evidence for direct CP violation.Comment: submitted to PR
Evidence for the Suppressed Decay B- -> DK-, D -> K+pi-
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.Comment: 6 pages, 2 figures, 2 tables, accepted by Physical Review Letter
Observation of and search for in B decays
We report a study of and
decay modes using events collected at the
\Upsilon(4S)e^+ e^-X(3872) \to J/\psi \gamma\chi_{c2} \to J/\psi \gammaB\to (X_{c\bar{c}}\gamma) KX(3872) \to \psi' \gamma\mathcal{B}(B^{\pm} \to X(3872)
K^{\pm}) \mathcal{B}(X(3872) \to J/\psi\gamma)=(1.78^{+0.48}_{-0.44}\pm
0.12)\times 10^{-6}\mathcal{B} (B^{\pm} \to\chi_{c2} K^{\pm})=(1.11^{+0.36}_{-0.34} \pm 0.09) \times 10^{-5}\mathcal{B}(B^{\pm} \to
X(3872) K^{\pm}) \mathcal{B}(X(3872) \to \psi'\gamma)<3.45\times 10^{-6}$
(upper limit at 90% C.L.) and also provide upper limits for other searches.Comment: 6 pages, 3 figure
Observation of and Evidence for
We report the first observation of and first
evidence for , which are CP eigenstate decay modes.
These results are obtained from of data collected at
the resonance with the Belle detector at the KEKB
collider. We measure the branching fractions with a significance of , and
with a significance of . The last error
listed is due to uncertainty in the number of produced pairs.Comment: 5 pages, 2 figures, 2 tables, published in PR
Precision measurement of charged pion and kaon differential cross sections in electron-positron annihilation at Q = 10.52 GeV
Measurements of inclusive differential cross sections for charged pion and
kaon production in electron-positron annihilation have been carried out at a
center-of-mass energy of Q = 10.52 GeV. The measurements were performed with
the Belle detector at the KEKB electron-positron collider using a data sample
containing 113 million e+e- -> qqbar events, where q={u,d,s,c}. We present
charge-integrated differential cross sections d\sigma_h+-/dz for h+- = pi+-,
K+- as a function of the relative hadron energy z = 2*E_h / sqrt{s} from 0.2 to
0.98. The combined statistical and systematic uncertainties for pi+- (K+-) are
4% (4%) at z ~ 0.6 and 15% (24%) at z ~ 0.9. The cross sections are the first
measurements of the z-dependence of pion and kaon production for z > 0.7 as
well as the first precision cross section measurements at a center-of-mass
energy far below the Z^0 resonance used by the experiments at LEP and SLC.Comment: 7 pages, 3 figures. Ancillary file including all cross section and
uncertainty values with 10 pages, 5 figure
Semi-inclusive studies of semileptonic decays at Belle
We present an analysis of the semi-inclusive decays and , where denotes a final state that
may consist of additional hadrons or photons and is an electron or muon.
The studied decays are contained in the
data sample collected by the Belle detector at the KEKB
asymmetric-energy collider. The branching fractions of the decays are
measured to be and
, where the first two uncertainties
are statistical and systematic and the last is due to external parameters. The
measurement also provides an estimate of the
production cross-section, ,
at the center-of-mass energy .Comment: 13 pages, 2 figures, submitted to Phys. Rev.
Observation of
We report the first observation of the decays . The data sample of fb used in this analysis corresponds
to million pairs, collected at the resonance by
the Belle detector at the KEKB asymmetric-energy collider. We
observe and excesses of events for the two decay
modes and measure the branching fractions of and to be
and ,
respectively, where the first uncertainties are statistical and the second are
systematic. These results are not compatible with the predictions based on the
generalized factorization approach. In addition, a threshold enhancement in the
di-baryon () system is observed, consistent with that observed
in similar decays.Comment: 16 pages, 3 figures and 3 tables, submitted to PR
- …