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{\bf Abstract Registration Number 579} \\
{\bf Parallel sessions: 10} \\
{\bf Plenary sessions: 12}
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\abstractheader{\bf A Search for Leptoquark Bosons in DIS at High $Q^2$ 
at HERA \\
H1 Collaboration, DESY}

\abstractbody{
A search for new bosons possessing couplings to lepton-quark pairs is 
performed in the H1 experiment at HERA using 1994$\rightarrow$1997 data 
corresponding to an integrated luminosity of $37$\, pb$^{-1}$.
The very high $Q^2$ neutral (NC) and charged current (CC) data is compared 
to Standard Model expectations from deep inelastic scattering.
The excess of events previously observed with the 1994$\rightarrow$1996
data remains, although less significant.
The analysis is extended to cover also any direct positron-quark 
fusion processes leading to decays into lepton-quark pairs of either the 
first, the second, or the third generation. No event $\mu + jet$ or
$\tau + jet$ candidates are found to be compatible with two body decay
hypothesis of a leptoquark.
Assuming that the excess of NC-like events is due to a statistical 
fluctuation, the data is used to constrain the direct $s$-channel 
production of first generation leptoquarks.
Compared with earlier results, the exclusion limits are considerably 
improved for leptoquarks which could be produced via 
$e^+$-{\it valence~quark} fusion and extend far beyond the 
coupling-mass domain covered so far at other colliders for a small 
branching ratio in $e^+ q$. 
}

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