  Measuring the abundances of neutron-capture elements in Galactic disk stars
is an important part of understanding key stellar and galactic processes. In
the optical wavelength regime a number of different neutron-capture elements
have been measured, however from the infrared H-band only the s-process
dominated element cerium has been accurately measured for a large sample of
disk stars. The more r-process dominated element ytterbium has only been
measured in a small subset of stars so far. In this study we aim to measure the
ytterbium (Yb) abundance of local disk giants using the Yb II line at
$\lambda_\text{air}$=16498\AA. We also compare the resulting abundance trend
with Ce and Eu abundances for the same stars to analyse the s- and r-process
contributions. We analyse 30 K-giants with high-resolution H-band spectra using
spectral synthesis. The very same stars have already been analysed using
high-resolution optical spectra using the same method, but the abundance of Yb
was not possible to determine from those spectra due to blending issues for
stars with [Fe/H]>-1. In this present analysis, we utilise the stellar
parameters determined from the optical analysis. We determined the Yb
abundances with an estimated uncertainty for [Yb/Fe] of 0.1 dex. From
comparison, the trend of [Yb/Fe] follows closely the [Eu/Fe] trend and has
clear s-process enrichment in identified s-rich stars. From the comparison,
both the validity of the Yb abundances are ensured, and the theoretical
prediction of a roughly 40/60 s-/r-process contribution to Yb's origin is
supported. These results show that with a careful and detailed analysis of
infrared spectra, reliable Yb abundances can be derived for a wider sample of
cooler giants in the range -1.1<[Fe/H]<0.3. This is promising for further
studies of the production of Yb and for the r-process channel, key for
Galactochemical evolution, in the infrared.
