The role of $ρ-ω$ interference in semileptonic $B \to π^+ π^- \ell \bar ν_\ell$ decays

• DOI: 10.48550/arxiv.2401.08779
• Publication Date: 2024-01-01
• Authors: Florian U. Bernlo...; S. Wallner
• Keywords: Branching fraction; Bar (unit); Semileptonic decay

It is long known that interference effects play an important role in understanding the shape of $\pi^+\pi^-$ spectrum resonances near threshold. In this manuscript we investigate $\rho-\omega$ study semileptonic $B \to \pi^+ \pi^- \ell \bar \nu_\ell$ decays. We determine for first time strong phase between \rho^0 and \omega from a recent Belle measurement $m_{\pi\pi}$ \nu_\ell$. find $ \phi_{\rho-\omega} = \left( -46_{-67}^{+155} \right)\unicode{xb0}$ extract branching fraction $\mathcal{B}(B \nu_\ell) \left(1.41_{-0.38}^{+0.49} \right) \times 10^{-4} $. addition, set limit on $S$-wave component within mass window ranging $2 m_\pi$ to $1.02 \, \mathrm{GeV}$ 0.51 \,\, \mathrm{at} 90\% \mathrm{CL} also absolute value Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|_{\rho-\omega} 3.03^{+0.49}_{-0.44} 10^{-3}$, which takes into account interference.