The delivery of radiofrequency (RF) energy through conventional catheter electrodes is often associated with coagulation necrosis at the tissue-electrode interface, with resultant impedance rise and ...limited lesion size. This study was performed to examine the effects of catheter tip cooling during RF delivery, to test the hypothesis that such cooling would decrease the likelihood if impedance rise and allow the creation of larger endomyocardial lesions.
The experiments were performed in eight open chest, anesthetized sheep. RF lesions were created within both ventricular chambers of each animal through a catheter tip that could be cooled with a saline perfusate. Assignment of cooled versus noncooled RF delivery to either ventricle was alternated from one animal to the next. In each set of experiments, lesion volumes relative to the mode of RF delivery were compared. The mean power delivered via the cooled electrode (22.04 +/- 4.51 W) was significantly higher than that delivered via the noncooled electrode (6.10 +/- 2.47 W; P < 0.001). The mean duration of RF delivery was 42.7 +/- 11.2 sec for noncooled lesions versus 49.2 +/- 6.8 sec for cooled lesions (P < 0.01). Mean lesion volume was 436.07 +/- 177.00 mm3 for noncooled RF delivery versus 1247.78 +/- 520.51 mm3 for cooled RF delivery (P < 0.001). This significantly larger lesion size with cooled RF delivery was associated with no instance of impedance rise in 27 attempts versus 11 impedance rises in 28 attempts with noncooled RF (P < 0.001).
Delivery of RF energy through a cooled catheter tip allows the creation of larger endomyocardial lesions by limiting the occurrence of impedance rise despite the delivery of greater energy. These observations suggest that, under certain conditions, resistive tissue heating at a distance from the site of current delivery may play an important role in RF ablation therapy.
The lifetime of the τ lepton is measured using the process e+ e- → τ+ τ- , where both τ leptons decay to 3πν(τ). 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 between τ+ and τ- is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ<7.0×10(-3) at 90% C.L.
In this work, we report new measurements of the total cross sections for e+e- → Υ ( n S ) π+π- ( n=1 , 2, 3) and e+e- → b b ¯ from a high-luminosity fine scan of the region s=10.63–11.05 GeV with the ...Belle detector. We observe that the Υ ( n S ) π+π- spectra have little or no nonresonant component and extract from them the masses and widths of Υ ( 10860 ) and Υ ( 11020 ) and their relative phase. We find M10860= ( 10891.1±3.2-1.7+0.6 ) MeV / c2 and Γ 10860= ( 53.7-5.6 -5.4+7.1 +1.3 ) MeV and report first measurements M11020= ( 10987.5-2.5 -2.1+6.4 +9.0 ) MeV / c2 , Γ 11020= ( 61-19 -20+9 +2 ) MeV , and Φ11020-Φ10860= ( -1.0±0.4-0.1+1.4 ) rad .
We report a search for B decays to selected final states with the ηc meson: B± → K±ηcπ+π-, B± → K±ηcω, B± → K±ηcη and B± → K±ηcπ0. The analysis is based on 772 × 106 BB-bar pairs collected at the ...Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We set 90% confidence level upper limits on the branching fractions of the studied B decay modes, independent of intermediate resonances, in the range (0.6–5.3) × 10-4. We also search for molecular-state candidates in the D0D*-bar0 - D-bar0D*0, D0D-bar0 + D-bar0D0 and D*0D*-bar0 + D*-bar0D*0 combinations, neutral partners of the Z(3900)± and Z(4020)±, and a poorly understood state X(3915) as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range (0.6–6.9) × 10-5.
Evidence for B¯s0→Λc+Λ¯π Solovieva, E.; Chistov, R.; Adachi, I. ...
Physics letters. B,
10/2013, Volume:
726, Issue:
1-3
Journal Article
Peer reviewed
Using 121.4 fb−1 of data collected with the Belle detector at the ϒ(5S) resonance at the KEKB asymmetric-energy e+e− collider, we report evidence for the B¯s0→Λc+Λ¯π− decay mode with a measured ...branching fraction (3.6±1.1stat.−0.5+0.3syst.±0.9Λc+±0.7NB¯s0)×10−4 and a significance of 4.4 standard deviations. This is the first evidence for a baryonic Bs0 decay.
Evidence for B¯s0→Λc+Λ¯π Adachi, I.; Asner, D. M.; Aushev, T. ...
Physics letters. B,
08/2013, Volume:
726, Issue:
1-3
Journal Article
Peer reviewed
Open access
Using 121.4 fb–1 of data collected with the Belle detector at the Y(5S) resonance at the KEKB asymmetric-energy e+e- collider, we report evidence for the B¯$^{0}_{s}$ → Λ$^{+}_{c}$Λ¯π– decay mode ...with a measured branching fraction (3.6 ± 1.1stat.$^{+0.3}_{-0.5}$syst. ± 0.9Λ$^{+}_{c}$ ± 0.7 NB¯$^{0}_{s}$) x 10–4 and a significance of 4.4 standard deviations. Here, this is the first evidence for a baryonic B$^{0}_{s}$ decay.
PDF
