  Since the first surprising results on the spin structure of the proton by the
EMC experiment in the late 1980s, much progress has been made in understanding
the origin of the proton spin. However, the sea quark contribution to the
proton spin, for example, the helicity distributions of the strange quark
(anti-quark), $s(\bar{s})$, is still not well constrained by experimental data.
Since the $s(\bar{s})$ is expected to carry a substantial fraction of the spin
of the $\Lambda(\bar{\Lambda})$ hyperon, measurements of the longitudinal spin
transfer, $D_{LL}$, of the $\Lambda(\bar{\Lambda}$) hyperon can thus shed light
on the helicity distribution of the $s(\bar{s})$ and the longitudinally
polarized fragmentation functions. In these proceedings, we will present the
status of the $\Lambda(\bar{\Lambda}$) $D_{LL}$ analysis using data collected
at RHIC-STAR in 2015, for the pseudo-rapidity $|\eta| < 1.2$ and transverse
momenta up to $8.0$ GeV$/c$. The $D_{LL}$ as a function of the longitudinal
momentum fraction of the $\Lambda(\bar{\Lambda})$ hyperon in the jet is also
investigated. This data set is about twice as large as the 2009 data used for
the previously published $D_{LL}$ results.
