  A search for single sneutrino production under the assumption that R-parity
is violated via a single dominant $LL\bar{E}$ coupling is presented. This
search considers the process ${\rm e} \gamma {\smash{\mathop{\to}}}
\tilde{\nu}\ell$ and is performed using the data collected by the ALEPH
detector at centre-of-mass energies from 189 GeV up to 209 GeV corresponding to
an integrated luminosity of 637.1 $\mathrm{pb}^{-1}$. The numbers of observed
candidate events are in agreement with Standard Model expectations and 95%
confidence level upper limits on five of the $LL\bar{E}$ couplings are given as
a function of the assumed sneutrino mass.
