Production properties of $K^\star(892)^\pm$ vector mesons and their spin alignment as measured in the NOMAD experiment

Abstract

First measurements of $K^\star(892)^\pm$ mesons production properties and their spin alignment in $\nu_\mu$ charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For ${K^\star}^+$ and ${K^\star}^-$ mesons produced in $\nu_\mu$ CC interactions and decaying into $K^0 \pi^\pm$ we have found the following yields per event: $(2.6\pm0.2(\text{stat.})\pm0.2(\text{syst.}))\%$ and $(1.6\pm0.1(\text{stat.})\pm0.1(\text{syst.}))\%$ respectively, while for the ${K^\star}^+$ and ${K^\star}^-$ mesons produced in $\nu\text{NC}$ interactions the corresponding yields per event are: $(2.5\pm0.3(\text{stat.})\pm0.3(\text{syst.}))\%$ and $(1.0\pm0.3(\text{stat.})\pm0.2(\text{syst.}))\%$. The results obtained for the $\rho_{00}$ parameter, $0.40\pm0.06(\text{stat.})\pm0.03(\text{syst.})$ and $0.28\pm0.07(\text{stat.})\pm0.03(\text{syst.})$ for $K^\star(892)^+$ and $K^\star(892)^-$ produced in $\nu_\mu$ CC interactions, are compared to theoretical predictions tuned on LEP measurements in $e^+e^-$ annihilation at the $Z^0$ pole. For $K^\star(892)^+$ mesons produced in $\nu\text{NC}$ interactions the measured $\rho_{00}$ parameter is $0.66\pm0.10(\text{stat.})\pm0.05(\text{syst.})$.