3,116 research outputs found
Measurement of the τ-lepton Lifetime at Belle
The lifetime of the τ lepton is measured using the process e+e−→τ+τ−, where both τ leptons decay to 3πντ. The result for the mean lifetime, based on 711 fb−1 of data collected with the Belle detector at the ϒ(4S) resonance and 60 MeV below, is τ=(290.17±0.53(stat)±0.33(syst))×10−15 s. The first measurement of the lifetime difference betweenτ+ and τ− is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ\u3c7.0×10−3 at 90% C.L
The Concept Of Deep Learning: Recognizing Elements In Cartographic Images
In the process of digitizing archives, there is a problem of transferring the obtained data to a vector image to further work with the obtained result, for example, take the cartographic schemes of hydraulic structures. To solve this problem, consider deep learning. Deep learning, in turn, is a class of machine learning algorithms that uses a multilayer system of nonlinear filters to separate the required characteristics with transformations. Consider how deep learning works, on the example of recognizing elements in a cartographic image
Search for the h_c meson in B^+- ->h_c K^+-
We report a search for the meson via the decay chain , \etac \gamma with and
. No significant signals are observed. We obtain upper limits on the
branching fractions for in bins of the
invariant mass. The results are based on an analysis of 253
fb of data collected by the Belle detector at the KEKB
collider.Comment: 12 pages, 6 figures, submitted to Phys. Rev.
Evidence for Direct CP Violation in and Observation of
We report measurements of the branching fractions and CP asymmetries for B^+-
-> eta h^+- (h = K or pi) and the observation of the decay B^0 -> eta K^0 from
the final data sample of 772x10^6 BBbar pairs collected with the Belle detector
at the KEKB asymmetric-energy e^+e^- collider. The measured branching fractions
are Br(B^+- -> eta K^+-) = (2.12 +- 0.23 +- 0.11)x10^-6}, Br(B^+- -> eta pi^+-)
= (4.07 +- 0.26 +- 0.21)x10^{-6} and Br(B^0 -> eta K^0) = (1.27^{+0.33}_{-0.29}
+- 0.08)x10^-6, where the last decay is observed for the first time with a
significance of 5.4 standard deviations (\sigma). We also find evidence for CP
violation in the charged B modes, A_{CP}(B^+- -> eta K^+-) = -0.38 +- 0.11 +-
0.01 and A_{CP}(B^+- -> eta pi^+- = -0.19 +- 0.06 +- 0.01 with significances of
3.8 sigma and 3.0 sigma, respectively. For all measurements, the first and
second uncertainties are statistical and systematic, respectively.Comment: 6 pages, 3 figures, 1 tabl
Measurement of CP asymmetries in decays
We report measurements of CP violation parameters in
decays based on a data sample of pairs collected
with the Belle detector at the KEKB asymmetric-energy collider. We
use decays for both mixing-induced and direct
violating asymmetry measurements and decays for the
direct CP violation measurement. The CP violation parameters obtained are and
. The
branching fraction of decay is measured to be
. The observed value
differs by 1.9 standard deviations from the value expected from an isospin sum
rule.Comment: 6 pages, 3 figure
Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions
We report measurements of CP violation parameters in B0->Ks pi0 gamma
transitions based on a data sample of 535x10^6 BB pairs collected with the
Belle detector at the KEKB asymmetric-energy e+ e- collider. One neutral B
meson is fully reconstructed in the B0->Ks pi0 gamma mode. The flavor of the
accompanying B meson is identified from its decay products. For a Ks pi0
invariant mass up to 1.8 GeV/c^2, we obtain S = -0.10 +- 0.31 +- 0.07 and A =
-0.20 +- 0.20 +- 0.06. For a Ks pi0 invariant mass near the K*0(892) resonance,
we obtain S = -0.32 +0.36-0.33 +-0.05 and A=-0.20 +-0.24 +-0.05.Comment: 6 pages, 3 figures, accepted by PR
Search for CP Violation in the Decays
We have searched for CP violation in the decays
where denotes a neutral pseudo-scalar meson which is either a ,
, or using KEKB asymmetric-energy collision data
corresponding to an integrated luminosity of 791 fb collected with the
Belle detector. No evidence of significant CP violation is observed. We report
the most precise CP asymmetry measurement in the decay to date: . We also report the first measurements of
CP asymmetries in the decays and : and , respectively
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