Analysis of the Kpi hadronic state interaction using D into K-pi+mu+nu semileptonic decays from the FOCUS experiment

TL;DR

This paper analyzes the semileptonic decay D+ into K-pi+mu+nu, measuring resonance parameters, scalar contributions, and setting upper limits on certain decay modes, providing insights into hadronic interactions in charm decays.

Contribution

It provides detailed measurements of resonance parameters and scalar contributions in D+ semileptonic decays, with new limits on specific decay channels, enhancing understanding of hadronic effects.

Findings

Scalar contribution of 5.30% with uncertainties

K*(892) resonance mass and width measured

Upper limits set for K*(1680) and K*_0(1430) decay ratios

Abstract

We present a four-body semileptonic charm decay D^+ into K^-pi^+mu^+nu analysis in the range of 0.65 GeV/c^2 < mkpi < 1.5 GeV/c^2. We observe a low mass scalar contribution of 5.30 +- 0.74 + 0.99 - 0.96 % with respect to the total D^+ into K^-pi^+mu^+nu decay, compatible with the phase shift found by the LASS elastic scattering experiment. For the K*(892) resonance, we obtain a mass of 895.41 +- 0.32 + 0.35 - 0.43 MeV/c^2, a width of 47.79 +- 0.86 + 1.32 - 1.06 MeV/c^2, and a Blatt-Weisskopf damping factor parameter of 3.96 +- 0.54 + 1.31 - 0.90 GeV^(-1). We also report 90% CL upper limits of 4% and 0.64% for the branching ratios Gamma(D^+ into K*(1680)mu^+nu)/Gamma(D^+ into K^-pi^+mu^+nu) and Gamma(D^+ into K*_0(1430)mu^+nu)/Gamma(D^+ into K^-pi^+mu^+nu), respectively.