Isolated Leptons and Missing PT: H1+ZEUS combination 

The search for events containing isolated leptons (electrons or muons) and
missing transverse momentum produced in $e^\pm p$ collisions 
is performed with the H1 and ZEUS detectors at HERA in the period
1994--2007. The analysed data sample corresponds to an integrated 
luminosity of 0.97~fb$^{-1}$. A total of 87 events are observed in the
data, compared to a Standard Model (SM) prediction of 
92.7~$\pm$~11.2, dominated by the single W production. 
At large hadronic transverse momentum $P_{T}^{X} >$~25~GeV, a total of 29
events are observed compared to a SM 
prediction of 25.3~$\pm$~3.2. In this kinematic region, 23 events are
observed in the $e^{+}p$ data compared to a SM prediction of 
14.6~$\pm$~1.9. This is the first common analysis of this event topology at
HERA. The excess with a significance of 3 sigma reported by 
the H1 collaboration is reduced to 1.8 sigma after the combination with
ZEUS result in the common phase space.