We report chemical abundances of 14 young \alpha -rich stars including neutron-capture elements based on high-quality optical spectra from HIRES/Keck I and differential line-by-line analysis .
From the comparison of the abundance patterns of young \alpha -rich stars to those of nearby bright red giants with a similar metallicity range ( -0.7 < [ \mathrm { Fe / H } ] < -0.2 ) , we confirm their high \alpha -element abundances reported by previous studies based on near-infrared spectroscopy .
We reveal for the first time low abundances of s -process elements and high abundances of r -process elements .
All the abundances are consistent with those seen in typical \alpha -rich population of the Galactic disk , and no abundance anomalies are found except for Li-enhancement in one object previously reported and mild enhancement of Na in two stars .
In particular , the lack of s -process enhancement excludes the hypothesis that mass transfer from asymptotic giant branch stars plays an important role in the formation of young \alpha -rich stars .
The high frequency of radial velocity variation ( more than 50 \% ) is also confirmed .
We argue that mass transfer from low-mass red giants is the likely dominant formation mechanism for young \alpha -rich stars .