Study of the decay $D^0\rightarrow \rho(770)^-e^+\nu_e$

TL;DR

This paper measures the branching fraction and form-factor ratios of the semileptonic decay D^0→ρ(770)^-e^+ν_e with high precision using BESIII data, providing valuable insights into charm meson decay dynamics.

Contribution

It provides the most precise measurement to date of the branching fraction and form-factor ratios for D^0→ρ(770)^-e^+ν_e decay, improving understanding of hadronic effects in charm semileptonic decays.

Findings

Branching fraction measured as (1.439 ± 0.033(stat) ± 0.027(syst)) ×10^{-3}

Form-factor ratio r_V = 1.548 ± 0.079(stat) ± 0.041(syst)

Form-factor ratio r_2 = 0.823 ± 0.056(stat) ± 0.026(syst)

Abstract

We present a study of the semileptonic decay $D^0\rightarrow \pi^-\pi^0e^{+}\nu_{e}$ using an $e^+e^-$ annihilation data sample of $7.93~\mathrm{fb}^{-1}$ collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The branching fraction of $D^0\to \rho(770)^-e^+\nu_e$ is measured to be $(1.439 \pm 0.033(\rm stat.) \pm 0.027(\rm syst.)) \times10^{-3}$, which is a factor 1.6 more precise than previous measurements. By performing an amplitude analysis, we measure the hadronic form-factor ratios of $D^0\to \rho(770)^-e^+\nu_e$ at $q^2=0$ assuming the single-pole-dominance parametrization: $r_{V}=V(0)/A_1(0)=1.548\pm0.079(\rm stat.)\pm0.041(\rm syst.)$ and $r_{2}=A_2(0)/A_1(0)=0.823\pm0.056(\rm stat.)\pm0.026(\rm syst.)$.