We report new measurements of the decays $B\toρ^+ γ$, $B \to ρ^0 γ$ and $B \to ωγ$ using a data sample of $657 \times 10^6$ $B$ meson pairs accumulated with the Belle detector at the KEKB $e^+ e^-$ collider. We measure branching fractions ${\cal B}(B^+ \to ρ^+ γ) = (8.7^{+2.9}_{-2.7}{}^{+0.9}_{-1.1})\times 10^{-7}$, ${\cal B}(B^0 \to ρ^0 γ) = (7.8^{+1.7}_{-1.6}{}^{+0.9}_{-1.0}) \times 10^{-7}$ and ${\cal B}(B^0 \to ωγ) = (4.0^{+1.9}_{-1.7} \pm 1.3) \times 10^{-7}$. We also report the isospin asymmetry $Δ(ργ) = -0.48^{+0.21}_{-0.19}{}^{+0.08}_{-0.09}$; and the first measurement of the direct CP-violating asymmetry $A_{CP}(B^+ \to ρ^+ γ) = -0.11\pm{0.32}\pm{0.09}$, where the first and second errors are statistical and systematic, respectively.
本文给出了B -> K（*）1 + 1-稀有衰变的新的BABAR测量结果，包括分支分数、同位旋不对称性、直接CP破坏和J/psi共振以上双轻子质量的轻子味普适性.在K1 + 1-和K* 1 + 1-衰变中都观察到出乎意料的大的同位旋不对称性。对于Kl +l-和K* l+l-的组合数据，发现与SM的预测有3.9 σ的显著偏差.此外，最近报道了BABAR在B -> K* l+l-的角分析结果，其中测量了J/psi共振以下和以上的双轻子质量的K* 纵向极化和轻子前后不对称性.最后，总结了最近从BABAR搜索B -> pil +1- $ from Belle and B -> K(*) nu anti nu$的结果。
Nucleon resonance contributions to the inclusive proton $F_2$ and $F_L$ structure functions are computed from resonance electroexcitation amplitudes in the mass range up to 1.75 GeV extracted from CLAS exclusive meson electroproduction data. Taking into account for the first time quantum interference effects, the resonance contributions are compared with inclusive proton structure functions evaluated from $(e,e'X)$ cross section data and the longitudinal to transverse cross section ratio. Contributions from isospin-1/2 and 3/2 resonances remain substantial over the entire range of photon virtu…
This work summarizes the current status of the measured semileptonic branching fractions $B^{0,+} \to X_c μν$. The sum of exclusive measurements is compared with the inclusive determination, accounting for isospin extrapolation. Further derived quantities are computed, taking into account different explanations for the unmeasured components of the total branching fraction. These quantities focus on the charge breakdown of the final states, and are designed for use as inputs or comparisons in future experimental measurements.
Measurement of the B0 --> pi- l+ nu and B+ --> pi0 l+ nu Branching Fractions and Determination of |V_ub| in Y(4S) Events Tagged by a Fully Reconstructed B Meson
We report measurements of isospin asymmetry $Δ_{0-}$ and difference of direct $CP$ asymmetries $ΔA_{CP}$ between charged and neutral $B \to X_s γ$ decays. This analysis is based on the data sample containing $772 \times 10^6 B\bar{B}$ pairs that was collected with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. Using a sum-of-exclusive technique with invariant $X_s$ mass up to 2.8~GeV/$c^2$, we obtain $Δ_{0-} = \bigl[-0.48 \pm 1.49 {\rm (stat.)} \pm 0.97 {\rm (syst.)} \pm 1.15 {(f_{+-}/f_{00})}\bigr]$\% and $ΔA_{CP} = \bigl[+3.69 \pm 2.65 {\rm (stat.)} \pm 0.76{\rm (syst.)…
Search for pair-production of vector-like quarks in lepton+jets final states containing at least one $b$-tagged jet using the Run 2 data from the ATLAS experiment
利用ATLAS Run 2数据在轻子+喷注末态搜索矢量类夸克对产生，排除质量低于1700 GeV的$T$夸克（100%衰变至$Wb$）及低于1360 GeV的同位旋单态。
Search for the reaction channel $e^+ e^- \to ηη\,J/ψ$ and the isospin partner of the $Z_c(3900)$ at center-of-mass energies $\sqrt{s} = 4.226-4.950$ GeV
We present measurements of partial branching fractions of inclusive semileptonic $B \to X_u \, \ell^+\, ν_{\ell}$ decays using the full Belle data set of 711 fb$^{-1}$ of integrated luminosity at the $Υ(4S)$ resonance and for $\ell = e, μ$. Inclusive semileptonic $B \to X_u \, \ell^+\, ν_{\ell}$ decays are CKM suppressed and measurements are complicated by the large background from CKM-favored $B \to X_c \, \ell^+\, ν_{\ell}$ transitions, which have a similar signature. Using machine learning techniques, we reduce this and other backgrounds effectively, whilst retaining access to a large fract…
