  Many extensions of the Standard Model predict the existence of charged heavy
long-lived particles, such as $R$-hadrons or charginos. These particles, if
produced at the Large Hadron Collider, should be moving non-relativistically
and are therefore identifiable through the measurement of an anomalously large
specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived
particles through their track parameters in the vicinity of the interaction
vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns
to 30 ns. A search for such particles with the ATLAS detector at the Large
Hadron Collider is presented, based on a data sample corresponding to an
integrated luminosity of 18.4 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 8
TeV. No significant deviation from the Standard Model background expectation is
observed, and lifetime-dependent upper limits on $R$-hadrons and chargino
production are set. Gluino $R$-hadrons with 10 ns lifetime and masses up to
1185 GeV are excluded at 95$\%$ confidence level, and so are charginos with 15
ns lifetime and masses up to 482 GeV.
