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%
\newcommand{\GeV}{\rm GeV}
\newcommand{\TeV}{\rm TeV}
\newcommand{\pb}{\rm pb}
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\newcommand{\hdick}{\noalign{\hrule height1.4pt}}
\newcommand{\rpv}{\slash\hspace{-2.5mm}{R}_{p}}
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\begin{document}

\pagestyle{empty}

\begin{titlepage}

\noindent
\begin{center}
\begin{small}
\begin{tabular}{llrr}
Submitted to & & &
\epsfig{file=/h1/www/images/H1logo_bw_small.epsi
,width=2.cm} \\[.2em] \hline
\multicolumn{4}{l}{{\bf
                31st International Conference 
                on High Energy Physics, ICHEP02},
                July~24,~2002,~Amsterdam} \\
                 & Abstract:        & {\bf 979}    &\\
                 & Parallel Session & {\bf 10}   &\\ \hline
 & \multicolumn{3}{r}{\footnotesize {\it
    www-h1.desy.de/h1/www/publications/conf/conf\_list.html}} \\[.2em]
\end{tabular}
\end{small}
\end{center}
\vspace*{2cm}



\begin{center}
  \begin{Large}                   
  {\bf Search for new physics phenomena in  
    {\boldmath $e q$} contact interactions at HERA}

  \vspace*{1cm}
    {H1 Collaboration}
  \end{Large} 
\end{center}



\begin{abstract} \noindent
Deep-inelastic $e^\pm p$ scattering at high momentum transfer $Q^2$  
is used to search for $eq$ contact interactions associated to scales 
not directly accessible at {\sc Hera}.
The cross section measurements $\rm d \sigma / \rm d Q^2$,
corresponding to integrated luminosities of $16.4~\pb^{-1}$ of $e^-p$ data
and $98.6~\pb^{-1}$ of $e^+p$ data,
are well described by the Standard Model and 
are analysed to set constraints on new phenomena.
For conventional contact interactions lower limits can be set on
compositeness scales $\Lambda$ at $1.8 - 5.4~\TeV$ and
on couplings to leptoquarks and $R$-parity violating squarks
of $M/\lambda > 0.3 - 1.4~\TeV$.
A search for low scale quantum gravity effects in models with large extra 
dimensions gives limits on the effective Planck scale of $M_S > 0.8~\TeV$.
A form factor analysis yields a radius of 
$R_q < 0.8\cdot 10^{-18}$~m for the light quarks.
\end{abstract}


\end{titlepage}

\section*{Explanation of the Measurement}

The results presented in this contribution correspond to an update of
our earlier publication \cite{ci}. Background information on contact
interaction phenomenology can be found in that publication. The 
experimental method is almst identical to that described there. 
The results presented in \cite{ci} were based on an integrated luminosity
smaller than those presented here by a factor of approximately three. 
The full available H1 data from the first phase of HERA running is now
used, including data from both $e^+p$ and $e^-p$ running.

Figure 1 shows comparisons of H1 high $Q^2$ neutral current 
deep-inelastic scattering cross sections with standard model predictions. 
Figure 2 shows limits on compositeness scale parameters for various chiral
structures. In figure 3, the $Q^2$ dependence of the ratio of the data to
the standard model prediction is shown and also compared with the 
modified predictions based on VV models with compositeness scales at
the limits of those excluded. Figures 4 and 5 show the same thing for various
leptoquark scenarios and for large extra dimension models respectively. 
Limits on compositeness scales, leptoquark masses, $R$-parity violating 
couplings to supersymmetric squarks, the scale $M_s$ of models with large 
extra dimensions and quark radii are given
in tables 1-5. 




\begin{thebibliography}{99}

\bibitem{ci} H1 Collaboration, C. Adloff et al., Phys. Lett. {\bf B479} 
(2000) 358.

\end{thebibliography}



\pagenumbering{arabic}
%\mpara{hier ist eine Randnotiz}





\vfill
\clearpage

% Data Analysis cross sections
%
\begin{figure}[p] 
  \begin{center} \vspace*{-.5cm}
    \mbox{
      \epsfig{file=H1prelim-02-062.fig1a.eps,width=.49\textwidth,
        bbllx=0,bblly=0,bbury=570,bburx=420,clip}  \hfill
      \epsfig{file=H1prelim-02-062.fig1b.eps,width=.49\textwidth,
        bbllx=0,bblly=0,bbury=570,bburx=420,clip}
      }\\[1em]
    \mbox{
      \epsfig{file=H1prelim-02-062.fig1c.eps,width=.49\textwidth,
        bbllx=0,bblly=0,bbury=570,bburx=420,clip}  \hfill
      \epsfig{file=H1prelim-02-062.fig1d.eps,width=.49\textwidth,
        bbllx=0,bblly=0,bbury=570,bburx=420,clip}
      }
  \end{center} \vspace*{-.3cm}
  \caption{Differential cross sections
    ${\rm d}\sigma / {\rm d}Q^2$ at $\sqrt{s} = 318~\GeV$
    for $e^-p \rightarrow e^-X$ scattering (top) and 
    $e^+p \rightarrow e^+X$ scattering (bottom).
    H1 data are compared with Standard Model expectations 
    using CTEQ5D parton distributions.
    The errors include statistics and uncorrelated experimental systematics. 
    The normalisation uncertainties are 3\% ($e^-p$ data) 
    and 1.5\% ($e^+p$ data). }
  \label{cismxsec}
\end{figure} 


\begin{figure}[htb]
  \begin{center}
     \epsfig{file=H1prelim-02-062.fig2.eps,%
      bbllx=0,bblly=0,bbury=311,bburx=400,clip,%
      width=\textwidth}
  \end{center}
  \caption{Lower limits on compositeness scale parameters
    $\Lambda^\pm$ (95\% CL)
    from fits to the combined $e^+ p$ and $e^- p$ data.}
  \label{cilambda}
\end{figure} 

% illustration of VV model sensitivity
%
\begin{figure}[htb]
  \begin{center} 
    \mbox{
      \epsfig{file=H1prelim-02-062.fig3a.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth}
      \epsfig{file=H1prelim-02-062.fig3b.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth} }
  \end{center} %\vspace*{-.3cm}
  \caption{NC cross section ${\rm d}\sigma/{\rm d}Q^2$ at $\sqrt{s} = 318~\GeV$
    normalised to the Standard Model expectation.
    H1 data of  $e^-p$ and  $e^+p$ scattering
    are compared with VV compositeness models corresponding
    to 95\%~CL exclusion limits of $\Lambda^+$ and $\Lambda^-$. 
    The errors represent statistics and uncorrelated experimental systematics.}
  \label{civvxsec}
\end{figure} 


% Leptoquarks
%
\begin{figure}[htb]
  \begin{center} 
    \mbox{
      \epsfig{file=H1prelim-02-062.fig4a.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth}
      \epsfig{file=H1prelim-02-062.fig4b.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth} } \\[3ex]
    \mbox{
      \epsfig{file=H1prelim-02-062.fig4c.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth}
      \epsfig{file=H1prelim-02-062.fig4d.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth} }
  \end{center} %\vspace*{-.3cm}
  \caption{NC cross section ${\rm d}\sigma/{\rm d}Q^2$ at $\sqrt{s} = 318~\GeV$
    normalised to the Standard Model expectation. 
    H1 data of $e^-p$ and $e^+p$ scattering
    are compared with 95\%~CL exclusion limits of leptoquarks
    $S^L_{1}$ and $V^L_{1}$  (top), respectively
    $S^R_{1/2}$ and $V^R_{1/2}$ (bottom).
    The errors represent statistics and uncorrelated experimental systematics.}
  \label{cilqxsec}
\end{figure} 


% Large Extra Dimensions
%
\begin{figure}[t]
  \begin{center} 
    \mbox{
      \epsfig{file=H1prelim-02-062.fig5a.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth}
      \epsfig{file=H1prelim-02-062.fig5b.eps,%
        bbllx=0,bblly=0,bbury=420,bburx=360,clip,%
        width=.5\textwidth} }
  \end{center} %\vspace*{-.3cm}
  \caption{NC cross section ${\rm d}\sigma/{\rm d}Q^2$ at $\sqrt{s} = 318~\GeV$
    normalised to the Standard Model expectation.
    H1 data of $e^-p$ and $e^+p$ scattering
    are compared to gravitational effects of large extra dimensions 
    at scales $M_S$ (95\%~CL lower limits)
    with positive ($\lambda = +1$) and negative ($\lambda = -1$) coupling.
    The errors represent statistics and uncorrelated experimental systematics.}
  \label{ledeffect}
\end{figure}

\clearpage


% compositeness scales
\begin{table}[htb]
\begin{center}
{\large\bf H1 preliminary} \\[0.2em] 
\begin{tabular}{l c c}
   \hdick \\[-1.5ex]
 coupling & \ $\Lambda^+~[\TeV]$  &  $\Lambda^-~[\TeV]$ \ \\[1ex]
   \hdick \\[-1.5ex]
 $LL$    &   2.8  & 2.3  \\[.2em] 
 $RR$    &   2.8  & 2.3  \\[.2em] 
 $LR$    &   3.2  & 1.8  \\[.2em]
 $RL$    &   3.2  & 1.9  \\[0.6ex]
 $VV$    &   5.1  & 5.4  \\[.2em]
 $AA$    &   2.5  & 3.9  \\[.2em]
 $VA$    &   2.9  & 2.9  \\[0.6ex]
 $LL+RR$ &   3.8  & 3.7  \\[.2em] 
 $RL+LR$ &   4.3  & 4.1  \\[.2em]
 \hline
\end{tabular}
\end{center}
\caption{
  Compositeness scale parameters 
  $\Lambda^\pm$ (95\%~CL lower limits) for various chiral structures. 
  Results are given %for the present analysis of $e^-p$ and $e^+p$ data 
  for a combined analysis including all HERA I data.}
\label{etafits}
\end{table}

% leptoquarks
\begin{table}[htb]
\begin{minipage}{8cm}
\begin{center}
{\large\bf H1 preliminary}

\begin{tabular}{l c c  }
  \hdick \\[-1.5ex]
    &         &    all $e^+ p$ \& $e^-p$ \\[.5ex]
   LQ & $F$ & $M_{LQ}/\lambda$  $\,[ \GeV ]$ \\[.5ex]
  \hdick \\[-1.5ex]
   $S_0^L$ & 2 & 720 \\[.2em]
   $S_0^R$ & 2 & 670 \\[.2em]
   $\tilde{S}_0^R$ & 2 & 330 \\[.2em]
   $S_{1/2}^L$ & 0 & 870 \\[.2em]
   $S_{1/2}^R$ & 0 & 370 \\[.2em]
   $\tilde{S}_{1/2}^L$ & 0 & 430 \\[.2em]
   $S_1^L$ & 2 & 480 \\[1ex]
  \hline
\end{tabular}
\end{center}\end{minipage}\begin{minipage}{8cm}
\begin{center}
{\large\bf H1 preliminary}

\begin{tabular}{l c c  }
  \hdick \\[-1.5ex]
    &         &    all $e^+ p$ \& $e^-p$ \\[.5ex]
   LQ & $F$ & $M_{LQ}/\lambda$  $\,[ \GeV ]$ \\[.5ex]
  \hdick \\[-1.5ex]
   $V_0^L$ & 0 & 770 \\[.2em]
   $V_0^R$ & 0 & 640 \\[.2em]
   $\tilde{V}_0^R$ & 0 & 1000 \\[.2em]
   $V_{1/2}^L$ & 2 & 420 \\[.2em]
   $V_{1/2}^R$ & 2 & 940 \\[.2em]
   $\tilde{V}_{1/2}^L$ & 2 & 1020 \\[.2em]
   $V_1^L$ & 0 & 1380 \\[1ex]
  \hline
\end{tabular}
\end{center}\end{minipage}
\caption{Fermion number $F$ 
  and 95\%~CL lower limits on $M_{LQ}/\lambda$ for scalar (S) and vector (V) 
  leptoquarks.
  Results are given for a combined analysis including all HERA I data.
  Notation:  {\em L, R} is the lepton chirality,
  subscript $I = 0,\ 1/2,\ 1$ is the weak isospin,
  $\tilde{S}$ and $\tilde{V}$ differ by two units of hypercharge from $S$ and $V$.
  Quantum numbers and helicities are given for $e^-q$ and $e^-\bar{q}$ states.}
\label{lqfits}
\end{table}



% squarks
\begin{table}[htb]
\begin{center}
{\large\bf H1 preliminary}

\begin{tabular}{l c c }
  \hdick \\[-1.5ex]
    &         & all $e^+ p$ \& $e^-p$ \\[.5ex]
   $\rpv$ \ coupling & $\eta^q$ 
    & $M_{\tilde q}/\lambda'$\\[.5ex]
    & $[\lambda'^{\,2}/M_{\tilde q}^2]$ 
    & $[ \GeV ]$\\[1ex]
  \hdick \\[-1.5ex]
   %$S_0^L$  
   $\lambda'_{11k}$ \ \ \ $e^+ \bar u \to \bar{\tilde d}^{\,(k)}$ &
    \ $\eta^u_{LL} = +\frac{1}{2}$ \ & 720 \\[.2em]
   %$\tilde{S}_{1/2}^L$  
   $\lambda'_{1j1}$ \ \ \ $e^+ d \to \tilde{u}^{\,(j)}$ &
    \ $\eta^d_{LR} = -\frac{1}{2}$ \   & 430 \\[1ex]
  \hline
\end{tabular}
\end{center}
\caption{Coefficients $\eta^q_{ab}$
  and 95\%~CL lower limits on $M_{\tilde q}/\lambda'$ for 
  $R_p$ violating couplings to squarks.
  Results are given for a combined analysis 
  including all HERA I data. }
\label{sqfits}
\end{table}
 

% large extra dimensions
\begin{table}[htb]

\begin{center}
{\large\bf H1 preliminary}

\begin{tabular}{l c c c}
   \hdick \\[-1.5ex]
          & \ $e^- p$ $(318~\GeV)$ \ & \ $e^+ p$ $(318~\GeV)$ \
          & \ all $e^+ p$  \& $e^- p$   \\
 coupling \ \ & \ $M_S~[\TeV]$ \ & \ $M_S~[\TeV]$ \  & \ $M_S~[\TeV]$ \ \\[1ex]
  \hline \\[-1.5ex]
 $\lambda = +1$ & 0.58 & 0.77 & 0.83 \\[.2em]
 $\lambda = -1$ & 0.61 & 0.73 & 0.79 \\[.2em]
 \hline
\end{tabular}
\end{center}
\caption{
     Lower limits (95\%~CL) on the gravitational scale $M_S$ assuming
     positive ($\lambda = +1$) and negative ($\lambda = -1$) coupling from
     the present analysis of $e^-p$ and $e^+p$ data 
     and from a combined analysis including all HERA I data.}
\label{ledfits}
\end{table}


% quark radius
\begin{table}[htb]

\begin{center}
{\large\bf H1 preliminary}

\begin{tabular}{l c }
   \hdick \\[-1.5ex]
          & \ all $e^+ p$  \& $e^- p$   \\
 form factor \ \ & \ $R~[10^{-18}~\m]$ \ \\[1ex]
  \hline \\[-1.5ex]
 $f_e \equiv 1$ & 0.82 \\[.2em]
 $f_e = f_q$    & 0.57 \\[.2em]
 \hline
\end{tabular}
\end{center}

\caption{
     Lower limits (95\%~CL) on the quark radius
     assuming point-like leptons ($f_e \equiv 1$) 
     or common form factors ($f_e = f_q$)
     for the analysis including all HERA I data.}
\label{rqfits}
\end{table}


\end{document}

