Measurement of the $\Lambda^0_b$ lifetime in the exclusive decay $\Lambda^0_b\rightarrow J/\psi\Lambda^0$ in $p\bar p$ collisions at $\sqrt s=1.96$ $\text{TeV}$

Abstract

We measure the $\Lambda^0_b$ lifetime in the fully reconstructed decay $\Lambda^0_b\rightarrow J/\psi\Lambda^0$ using $10.4 \text{fb}^{−1}$ of $p\bar p$ collisions collected with the D0 detector at $\sqrt s=1.96 \text{TeV}$. The lifetime of the topologically similar decay channel $B^0\rightarrow J/\psi K^0_S$ is also measured. We obtain $\tau(\Lambda^0_b)=1.303±0.075(\text{stat})±0.035(\text{syst}) \text{ps}$ and $\tau(B^0)=1.508±0.025(\text{stat})±0.043(\text{syst}) \text{ps}$. Using these measurements, we determine the lifetime ratio of $\tau(\Lambda^0_b)/\tau(B^0)=0.864±0.052(\text{stat})±0.033(\text{syst})$.