000003333 001__ 3333
000003333 005__ 20221129123645.0
000003333 037__ $$aBELLE2-CONF-PH-2022-029
000003333 041__ $$aeng
000003333 088__ $$aBELLE2-CONF-DRAFT-2022-029
000003333 100__ $$aMoritz Bauer
000003333 245__ $$aReconstruction of B→ρℓνℓ decays identified using hadronic decays of the recoil B meson in 2019 -- 2021 Belle II data
000003333 260__ $$a$$c2022-11-29
000003333 300__ $$amult. p
000003333 520__ $$aWe present results on the semileptonic decays $B^0 \to \rho^- \ell^+ \nu_\ell$ and $B^+ \to \rho^0 \ell^+ \nu_\ell$ in a sample corresponding to 189.9/fb of Belle II data at the SuperKEKB $e^- e^+$ collider. Signal decays are identified using full reconstruction of the recoil $B$ meson in hadronic final states. We determine the total branching fractions via fits to the distributions of the square of the "missing" mass in the event and the dipion mass in the signal candidate and find ${\mathcal{B}(B^0\to\rho^-\ell^+ \nu_\ell) = (4.12 \pm 0.64(\mathrm{stat}) \pm 1.16(\mathrm{syst})) \times 10^{-4}}$ and ${\mathcal{B}({B^+\to\rho^0\ell^+\nu_\ell}) = (1.77 \pm 0.23 (\mathrm{stat}) \pm 0.36 (\mathrm{syst})) \times 10^{-4}}$ where the dominant systematic uncertainty comes from modeling the nonresonant $B\to (\pi\pi)\ell^+\nu_\ell$ contribution. 
000003333 700__ $$aNadia Ejlal Toutounji
000003333 700__ $$aPablo Goldenzweig
000003333 700__ $$aKevin Varvell
000003333 8560_ $$fmoritz.bauer@kit.edu
000003333 8564_ $$uhttps://docs.belle2.org/record/3333/files/BELLE2-CONF-PH-2022-029.pdf