\relax 
\citation{DPP}
\citation{Pompyt}
\citation{DiffVM}
\citation{WWA}
\@writefile{toc}{\contentsline {section}{\numberline {1}Introduction}{1}}
\@writefile{lof}{\contentsline {figure}{\numberline {1}{\ignorespaces Generic diagrams for the two processes, contributing to exclusive photoproduction of $\rho $ mesons associated with leading neutrons at HERA. (a) Double peripheral process, involving $\pi $-exchange at the proton vertex, which is considered as a {\em  signal} in present analysis. (b) Diffractive scattering in which neutron may be produced as a part of the proton dissociation system, $M_Y$, and which is treated as {\em  background} to the events of class (a).}}{1}}
\newlabel{fig:FD}{{1}{1}}
\@writefile{toc}{\contentsline {section}{\numberline {2}Analysis Outline and Main Results}{1}}
\citation{RS}
\citation{H1_rho}
\citation{ZEUS_rho}
\citation{pi_flux}
\citation{pi_flux}
\citation{gpiPN}
\newlabel{RS_rho}{{1}{2}}
\newlabel{OPE}{{2}{2}}
\citation{ZEUS_rho}
\citation{ZEUS_pi2p}
\citation{DPP}
\bibcite{DPP}{1}
\@writefile{toc}{\contentsline {section}{\numberline {3}Summary}{3}}
\bibcite{Pompyt}{2}
\bibcite{DiffVM}{3}
\bibcite{WWA}{4}
\bibcite{RS}{5}
\bibcite{H1_rho}{6}
\bibcite{ZEUS_rho}{7}
\bibcite{pi_flux}{8}
\bibcite{gpiPN}{9}
\bibcite{ZEUS_pi2p}{10}
\citation{H1_rho}
\citation{ZEUS_rho}
\citation{H1_rho}
\citation{ZEUS_rho}
\citation{pi_flux}
\citation{pi_flux}
\citation{DPP}
\citation{DPP}
\@writefile{lof}{\contentsline {figure}{\numberline {2}{\ignorespaces Distributions of $p_t^2$ and $\eta $ of $\rho ^0$, $x_L$ of neutron and $W_{\gamma p}$ for data and Monte Carlo simulations normalised to the data. Data points are shown with statistical errors only. The shaded green band indicates the uncertainty in the estimated background fraction.}}{5}}
\newlabel{fig:CP}{{2}{5}}
\@writefile{lof}{\contentsline {figure}{\numberline {3}{\ignorespaces Mass distribution of the $\pi ^+\pi ^-$ system for elastic $\rho ^0$ production with $p_t^2<1.0$ GeV$^2$. The data points are corrected for the detector efficiency. The curves represent different components contributing to the measured distribution and the BW resonant part extracted from the fit to the data. Analysis region $0.6<M_{\pi ^+\pi ^-}<1.1$ GeV is indicated by vertical arrows.}}{6}}
\newlabel{fig:mass}{{3}{6}}
\@writefile{lof}{\contentsline {figure}{\numberline {4}{\ignorespaces Ross-Stodolsky skewing parameter, $n_{RS}$, as a function of $p_t^2$ of $\pi ^+\pi ^-$ system. Values measured in this analysis are compared to previously obtained results for elastic photoproduction of $\rho ^0$ mesons, $\gamma p \to \rho ^0 p$, by H1\nobreakspace  {}\cite  {H1_rho} and ZEUS\cite  {ZEUS_rho} Collaborations.}}{7}}
\newlabel{fig:nRS}{{4}{7}}
\@writefile{lof}{\contentsline {figure}{\numberline {5}{\ignorespaces Differential cross section d$\sigma _{\gamma p}/{\rm  d}x_L$ compared to the predictions based on different versions of pion fluxes\nobreakspace  {}\cite  {pi_flux}. The data points are shown with statistical (inner error bars) and total (outer error bars) uncertainties, excluding overall normalisation error of $5.9\%$. All predictions are normalised to the data.}}{8}}
\newlabel{fig:dsdxl}{{5}{8}}
\@writefile{lof}{\contentsline {figure}{\numberline {6}{\ignorespaces Elastic cross section $\sigma ^{\rm  el}({\gamma \pi ^+} \to \rho ^0\pi ^+)$ as a function of photon-pion energy, $W_{\gamma \pi }$. The inner error bars represent the total experimental uncertainty and the outer error bars are experimental and model uncertainties added in quadrature, where the model error is due to pion flux uncertainties ($\sim 25\%$).}}{9}}
\newlabel{fig:sigma_gpi}{{6}{9}}
\@writefile{lof}{\contentsline {figure}{\numberline {7}{\ignorespaces Cross section of the reaction $\gamma p \to \rho ^0 n \pi ^+$ as a function of $W_{\gamma p}$ compared to prediction from POMPYT MC, which is normalised to the data. The dashed curve represents the Regge motivated fit $\sigma \sim W^{\delta }$ with $\delta = -0.33 \pm 0.06_{\rm  stat}\pm 0.13_{\rm  sys}$. The data points are shown with statistical (inner error bars) and total uncertainties (outer error bars) excluding overall normalisation error of $5.9\%$}}{10}}
\newlabel{fig:wgp}{{7}{10}}
\@writefile{lof}{\contentsline {figure}{\numberline {8}{\ignorespaces Differential cross section d$\sigma _{\gamma p}/{\rm  d}\eta $ compared to prediction from POMPYT MC. Inner error bars represent statistical errors and the outer error bars are total errors excluding overall normalisation uncertainty of $5.9\%$. Different $W$ dependence in data and Monte Carlo is reflected in pseudorapidity distribution of $\rho $ meson.}}{11}}
\newlabel{fig:eta}{{8}{11}}
\@writefile{lof}{\contentsline {figure}{\numberline {9}{\ignorespaces Differential cross section d$\sigma _{\gamma p}/{\rm  d}p_t^2$ of $\rho ^0$ mesons fitted with the sum of two exponential functions. The values of slopes are characteristic for double peripheral processes\nobreakspace  {}\cite  {DPP} in which an exchange of two Regge trajectories is involved.}}{12}}
\newlabel{fig:pt2}{{9}{12}}