  Solar energetic particles (SEPs) in the energy range 10s KeV/nucleon - 100s
MeV/nucleon originate from Sun. Their high flux near Earth may damage the space
borne electronics and generate secondary radiations harmful for the life on
Earth and thus understanding their energization on Sun is important for space
weather prediction. Impulsive (or ${}^{3}$He-rich) SEP events are associated
with the acceleration of charge particles in solar flares by magnetic
reconnection and related processes. The preferential acceleration of heavy ions
and the extra-ordinary abundance enhancement of ${}^3$He in the impulsive SEP
events are not understood yet. In this paper, we study ion acceleration in
magnetic reconnection by two dimensional hybrid-kinetic plasma simulations
(kinetic ions and inertial electron fluid). All the ions species are treated
self-consistently in our simulations. We find that heavy ions are
preferentially accelerated to energies many times larger than their initial
thermal energies by a variety of acceleration mechanisms operating in
reconnection. Most efficient acceleration takes place in the flux pileup
regions of magnetic reconnection. Heavy ions with sufficiently small values of
charge to mass ratio ($Q/M$) can be accelerated by pickup mechanism in outflow
regions even before any magnetic flux is piled up. The energy spectra of heavy
ions develop a shoulder like region, a non-thermal feature, as a result of the
acceleration. The spectral index of the power law fit to the shoulder region of
the spectra varies approximately as $(Q/M)^{-0.64}$. Abundance enhancement
factor, defined as number of particles above a threshold energy normalized to
total number of particles, scales as $(Q/M)^{-\alpha}$ where $\alpha$ increases
with the energy threshold. We discuss our simulation results in the light of
the SEP observations.
