1,373 research outputs found
Recent Results in Bottomonium
No full textGreat strides have been made in the understanding of bound states of the bottom quark, b, and its antiquark, (b) over bar, since the discovery of the first Upsilon resonances in 1977. These bound states, known as bottomonium, have a rich spectrum whose masses and transition amplitudes shed valuable light on the strong interactions. We review some recent developments in bottomonium physics, including the discovery of the spin-singlet states eta(b) (1S, 2S) and h(b) (1P, 2P), the first D-wave states, one or more candidates for spin-triplet.XbJ(3P) excitations, and above-threshold states with strong transitions to states below threshold. We also present information about transitions, production, and signatures of new physics
Search for violation in decays and observation of the Cabibbo-suppressed decay
No full textWe search for violation by measuring a -odd asymmetry in the
Cabibbo-suppressed decay, and
in the Cabibbo-favored and
decays. We use 980 of data collected by the Belle detector running at the KEKB
asymmetric-energy collider. The -violating -odd parameter
is measured to be
and
where the first
uncertainty is statistical and the second is systematic. We also report the
first observation of the Cabibbo-suppressed decay . The branching fraction is measured relative to
that of the analogous Cabibbo-favored decay :
Measurement of the branching fractions for Cabibbo-suppressed decays D+→K+K−π+π0 and D(s)+→K+π−π+π0 at Belle
No full textWe present measurements of the branching fractions for the singly Cabibbo-suppressed decays D+→K+K−π+π0 and D+s→K+π−π+π0, and the doubly Cabibbo-suppressed decay D+→K+π−π+π0, based on 980 fb−1 of data recorded by the Belle experiment at the KEKB e+e− collider. We measure these modes relative to the Cabibbo-favored modes D+→K−π+π+π0 and D+s→K+K−π+π0. Our results for the ratios of branching fractions are B(D+→K+K−π+π0)/B(D+→K−π+π+π0)=(11.32±0.13±0.26)%, B(D+→K+π−π+π0)/B(D+→K−π+π+π0)=(1.68±0.11±0.03)%, and B(D+s→K+π−π+π0)/B(D+s→K+K−π+π0)=(17.13±0.62±0.51)%, where the uncertainties are statistical and systematic, respectively. The second value corresponds to (5.83±0.42)×tan4θC, where θC is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for B(D+→K−π+π+π0) and B(D+s→K+K−π+π0) yields B(D+→K+K−π+π0)=(7.08±0.08±0.16±0.20)×10^−3, B(D+→K+π−π+π0)=(1.05±0.07±0.02±0.03)×10^−3, and B(D+s→K+π−π+π0)=(9.44±0.34±0.28±0.32)×10^−3, where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction
Angular analysis of the low K+K− invariant mass enhancement in B+→K+K−π+ decays
No full textWe study the decay B+→K+K−π+ and investigate the angular distribution of K+K− pairs with invariant mass below 1.1 GeV/c2. This region exhibits both a strong enhancement in signal and very large direct CP violation. We construct a coherent sum model for the angular distribution of S- and P-wave, and report the ratio of their amplitudes, the relative phase and the forward-backward asymmetry. We also report absolute differential branching fractions and direct CP asymmetry for the decay in bins of MK+K− and the differential branching fractions in bins of MK+π−. The results are based on a data sample that contains 772×10^6 BB ̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The measured overall branching fraction and the direct CP asymmetry are (5.38±0.40±0.35)×10^−6 and −0.170±0.073±0.017, respectively, where the first uncertainties are statistical and the second are systematic
Angular analysis of the low K+ K- invariant mass enhancement in B+ →K+ K- π+ decays
No full textWe study the decay B+→K+K-π+ and investigate the angular distribution of K+K- pairs with invariant mass below 1.1 GeV/c2. This region exhibits both a strong enhancement in signal and very large direct CP violation. We construct a coherent sum model for the angular distribution of the S- and P-wave, and report the ratio of their amplitudes, the relative phase and the forward-backward asymmetry. We also report absolute differential branching fractions and direct CP asymmetry for the decay in bins of MK+K- and the differential branching fractions in bins of MK+π-. The results are based on a data sample that contains 772×106 BB ̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The result favors the presence of S- and D-waves in low MK+K- region to the detriment of a P-wave
Measurement of branching fraction and direct asymmetry in charmless decays at Belle
No full textWe report a study of the charmless hadronic decay of the charged meson to the three-body final state . The results are based on a data sample that contains pairs collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider. The measured inclusive branching fraction and the direct asymmetry are and , respectively, where the first uncertainties are statistical and the second are systematic. The invariant mass distribution of the signal candidates shows an excess in the region below GeV/, which is consistent with the previous studies from BaBar and LHCb. In addition, strong evidence of a large direct asymmetry is found in the low-invariant-mass region
Measurement of the branching fraction and search for CP violation in decays at Belle
No full text9 pages, 4 figures, to be submitted to Phys. Rev. DInternational audienceWe measure the branching fraction for the Cabibbo-suppressed decay and search for violation via a measurement of the asymmetry as well as the -odd triple-product asymmetry . We use 922 fb of data recorded by the Belle experiment, which ran at the KEKB asymmetric-energy collider. The branching fraction is measured relative to the Cabibbo-favored normalization channel ; the result is , where the first uncertainty is statistical, the second is systematic, and the third is from uncertainty in the normalization channel. We also measure , and . These results show no evidence of CP violation
Observation of and
No full textInternational audienceWe report the study of B+→pΛ¯K+K- and B+→p¯ΛK+K+ decays using a 772×106 BB¯ pair data sample recorded on the ϒ(4S) resonance with the Belle detector at KEKB. The following branching fractions are measured: B(B+→pΛ¯K+K-)=(4.10-0.43+0.45±0.50)×10-6, B(B+→p¯ΛK+K+)=(3.70-0.37+0.39±0.44)×10-6, B(ηc→pΛ¯K-+c.c.)=(2.83-0.34+0.36±0.35)×10-3 and B(B+→pΛ¯ϕ)=( 7.95±2.09±0.77)×10-7, where c.c. denotes the corresponding charge-conjugation process. The intermediate resonance decays are excluded in the four-body decay measurements. We also find evidence for B(ηc→Λ(1520)Λ¯+c.c.)=(3.48±1.48±0.46)×10-3 and B(B+→Λ(1520)Λ¯K+)=( 2.23±0.63±0.25)×10-6. No significant signals are found for J/ψ→Λ(1520)Λ¯+c.c. and B+→Λ¯(1520)ΛK+; we set the 90% confidence level upper limits on their decay branching fractions as <1.80×10-3 and <2.08×10-6, respectively
Search for Violation and Measurement of the Branching Fraction in the Decay
No full textWe report a study of the decay using 921~fb of data collected at or near the and resonances with the Belle detector at the KEKB asymmetric-energy collider. The measured time-integrated CP asymmetry is and the branching fraction is = (1.32 0.02 0.04 0.04) 10, where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode () used in the analysis. These results are significantly more precise than previous measurements for this mode. The measurement is consistent with the Standard Model expectation
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