Search for heavy neutrinos at Belle Arinstein, K.; Aulchenko, V.; Bakich, A. M. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
04/2013, Letnik:
87, Številka:
7
Journal Article
Odprti dostop
We report on a search for heavy neutrinos in B-meson decays. The results are obtained using a data sample that contains 772 x 10 super(6) BB pairs collected at the Upsilon(4S) resonance with the ...Belle detector at the KEKB asymmetric-energy e super(+)e super(-) collider. No signal is observed and upper limits are set on mixing of heavy neutrinos with left-handed neutrinos of the Standard Model in the mass range 0.5-5.0 GeV/c super(2).
Abstract We present the first model-independent measurement of the CKM unitarity triangle angle ϕ 3 using B ± → D( K S 0 $$ {K}_{\mathrm{S}}^0 $$ π + π − π 0) K ± decays, where D indicates either a D ...0 or D ¯ $$ \overline{D} $$ 0 meson. Measurements of the strong-phase difference of the D → K S 0 $$ {K}_{\mathrm{S}}^0 $$ π + π − π 0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106 B B ¯ $$ \overline{B} $$ events collected at the Υ(4S) resonance. We obtain ϕ 3 = ( 5.7 − 8.8 + 10.2 $$ {5.7}_{-8.8}^{+10.2} $$ ±3.5±5.7) ° and the suppressed amplitude ratio r B = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ 3 is (−29.7, 109.5) ° , which is consistent with the current world average.
Measurements of inclusive differential cross sections for charged pion and kaon production in e⁺e⁻ annihilation have been carried out at a center-of-mass energy of √s=10.52 GeV. The measurements were ...performed with the Belle detector at the KEKB e⁺e⁻ collider using a data sample containing 113×106 e⁺e⁻→qq¯ events, where q={u,d,s,c}. We present charge-integrated differential cross sections dσh±/dz for h±={π±,K±} as a function of the relative hadron energy z=2Eh/√s from 0.2 to 0.98. The combined statistical and systematic uncertainties for π± (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 Z⁰ resonance used by the experiments at LEP and SLC.
Measurements of inclusive differential cross sections for charged pion and kaon production in e+e- annihilation have been carried out at a center-of-mass energy of s=10.52 GeV . The measurements were ...performed with the Belle detector at the KEKB e+e- collider using a data sample containing 113×106 e+e-→q q¯ events, where q= { u,d,s,c } . We present charge-integrated differential cross sections dσh±/dz for h±= { π±,K± } as a function of the relative hadron energy z=2Eh/s from 0.2 to 0.98. The combined statistical and systematic uncertainties for π± ( 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 Z0 resonance used by the experiments at LEP and SLC.
Evidence for B¯s0→Λc+Λ¯π Adachi, I.; Asner, D. M.; Aushev, T. ...
Physics letters. B,
08/2013, Letnik:
726, Številka:
1-3
Journal Article
Recenzirano
Odprti dostop
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.
We search for bottomonium states in $\Upsilon(2S)$ → ($\bar{bb}$) gamma decays with an integrated luminosity of 24.7fb-1 recorded at the $\Upsilon(2S)$ resonance with the Belle detector at KEK, ...containing (157.8 ± 3.6) X 106 $\Upsilon(2S)$ events. The ($\bar{bb}$) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and $K^0_S$ mesons. We find no evidence for the state recently observed around 9975 MeV ($X_{\bar{bb}}$) in an analysis based on a data sample of 9.3 X 106 $\Upsilon(2S)$ events collected with the CLEO III detector. We set a 90 % confidence-level upper limit on the branching fraction $Β$$\Upsilon(2S)$ → $X_{\bar{bb}\gamma}$ X $\sum_i$ $B$$X_{\bar{bb}}$ → $h_i$ $<$ 4.9 X 10-6, summed over the exclusive hadronic final states employed in our analysis. This result is an order of magnitude smaller than the measurement reported with CLEO data. We also set an upper limit for the $\eta_b(1S)$ state of $B$$\Upsilon(2S)$ → $\eta_b(1S)\gamma$ X $\sum_i$B$\eta_b(1S)$ → $h_i$ $<$ 3.7 X 10-6.
PDF
