A narrow resonance peak was observed at $1.54 \pm 0.01$ GeV/$c^2$ as an exotic baryon with strangeness $S = +1$ in the $\gamma + n \rightarrow K^+ + K^- + n$ reaction on $^{12}$C. The new state have a width smaller than $0.025$ GeV/$c^2$ and a Gaussian significance of $4.6\sigma$. It can not be interpreted as three quark state and is consistent with the lightest member of an antidecuplet of baryons predicted by the chiral soliton model.
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\begin{center}

{\bfseries EXOTIC STATE SEARCHES AT THE SPRING-8:
\\
OBSERVATION OF A PENTAQUARK STATE $\Theta^+$ BARYON}

\vskip 5mm

Yuji Ohashi on behalf of the LEPS collaboration
\vskip 5mm

{\small

 {\it
 SPring-8\\
Japan Synchrotron Radiation Research Institute\\
Mikazuki, Sayo, Hyogo, 679-5198, Japan\\
}
\vskip 5mm
%$\dag$
 {\it

E-mail: ohashi@spring8.or.jp

}}

\end{center}

\vskip 5mm



\begin{abstract}

A narrow resonance peak was observed at $1.54 \pm 0.01$ GeV/$c^2$ as an exotic baryon with strangeness $S = +1$ in the $\gamma + n \rightarrow K^+ + K^- + n$ reaction on $^{12}$C. The new state have a width smaller than $0.025$ GeV/$c^2$ and a Gaussian significance of $4.6\sigma$. It can 
not be interpreted as three quark state and is consistent with the lightest member of an antidecuplet of baryons predicted by the chiral soliton model.

\end{abstract}



\vskip 8mm
\vspace{4mm}
\begin{center}
{\large \bf INTRODUCTION}
\end{center}

The constituent quark model has been remarkably successful to 
describe most of the experimentally observed mesons and baryons. 
Beyond conventional hadrons, exotic states such as glueballs, hybrid 
mesons, and other multi-quark states are not prohibited in QCD.
There is a different approach by the Skyrme model~\cite{s1} that is 
originated in the same QCD.
In this direction, following the pioneering works~\cite{s2,s3}, 
Diakonov, Petrov and Polyakov (DPP) proposed a possible 
existence of the $S = +1\  J^P = 1/2^+$ resonance at $1.53$ 
GeV/$c^2$ with a width less than $0.015$ GeV/$c^2$ using the 
chiral soliton model~\cite{dpp}. The $\Theta^+$ (originally denoted 
the $Z^+$) is the lightest member of the anti-decuplet which appears 
as the third rotational excitation states. Their model simply assumes the 
relatively well established nucleon resonance $N (1710, 1/2^+) $ as 
a nucleon-like member of the anti-decuplet. The mass formula for the 
members of the antidecuplet is proposed as
\begin{eqnarray}
M = [1.89 -Y \times 0.18\ ]  \ GeV/c^2
\end{eqnarray}
where Y is a hypercharge.
 
Motivated by the resonance-like structure appeared 
around $K^+$ momentum of $1$ GeV/$c$ in 
both $K^+p$ and $K^+n$ total cross-sections, experimental 
studies on the $K^+N$ reactions started from 1960's. It is to be noted 
that most of the searches were performed in the mass range 
between 1.74 and 2.16 GeV/$c^2$. Although the possible $Z^*$ baryon 
resonances were reviewed in the 1986 baryon listings 
by the PDG~\cite{pdg}, evidence of their existence was concluded as poor.

One of our experimental goal is to search various kinds of 
exotic states through photo-nuclear reactions. The present 
experiment was motivated in part by the DPP prediction mentioned 
above, and the experimental result was published in the 
article~\cite{nprl}. We describe this paper including some issues 
that were not mentioned at the workshop or appeared afterward.

\vspace{6mm}
\begin{center}
{\large \bf EXPERIMENTAL METHOD}
\end{center}

\begin{wrapfigure}{R}{7.5cm}

\mbox{\epsfig{figure=yof1.eps,width=7cm}}

{\small{Figure 1.} Energy spectrum of a Laser-Electron Photon beam.\\
\ }

\end{wrapfigure}

The experiment was carried out at the Laser-Electron Photon facility 
at the SPring-8 (LEPS)~\cite{nnpa}. 
Photon beam is produced by Compton scattering of laser photons 
on the circulating 8 GeV electrons and beam energy is tagged by 
analyzing scattered electron momentum. 
The maximum photon energy is determined by the wave length 
of the laser, and it is 2.4 GeV when a 351 $n$m Ar laser is used. 

Energy spectrum of a photon beam is relatively flat as shown 
in Fig. 1 and photons are highly polarized when laser photons 
are polarized. Un-collimated beam size in standard 
deviation($\sigma$) is 3 mm vertcally and 8 mm horizontally 
at the target position about 70 m downstream of the Compton scattering region.
Typical tagged photon flux above 1.5 GeV was $\sim1 \times 10^6$ per second.

\begin{wrapfigure}{R}{9.5cm}
\vspace{-3mm}
\hspace{2mm}
\mbox{\epsfig{figure=yof2.epsf,width=8.1cm}}

{\small{Figure 2.} The LEPS detector setup.
\vspace{2mm}
}

\end{wrapfigure}

Experimental setup was designed for the study of $\phi$ meson 
production from protons. 
Photons hit a liquid hydrogen target (LH$_2$) of 5 cm thick after 
passing through a charged particle veto counter (VC).
The LEPS detector consisted of a start trigger counter (SC), a 
silica aerogel ${\rm\check{C}}$erenkov counter (AC), a silicon-strip 
vertex detector (SSD), an upstream drift chamber, a 0.7T dipole magnet, 
two sets of downstream drift chambers, and a time-of-flight scintillator 
array(TOF) as shown in Fig. 2. 
The detector acceptance covered forward angle of $\pm$0.4 
and $\pm$0.2 rad in the horizontal and vertical directions, respectively. 
Typical detector resolutions in $\sigma$ for tagged $E_{\gamma}$, 
momentum, time-of-flight, and mass (momentum dependent) were 
0.015 GeV/$c^2$, 0.006 GeV/c at 1 GeV/c, 150 $p$sec for a flight length 
of  $\sim 4$ m from the target to the TOF,  and 0.01 GeV/$c^2$ 
for 1 GeV/c kaon, respectively. Particle identification was applied 
within 3 $\sigma$ in this analysis, and its effectiveness can be 
viewed in the mass spectrum in Fig. 3. 


\setcounter{figure}{2}

\begin{figure}[t]
\vspace{-5mm}
%\hspace{-8mm}
\centerline{\epsfysize=2.6in\epsfbox{yof3.epsf}}
\vspace{-10mm}
\caption{The Mass distribution.
\label{fig:mass2} }
\end{figure}

$e^+e^-$ pairs produced in the very forward angles were blocked by 
horizontal lead bars which were set in the median plane inside the magnet gap. 
The trigger simply required a hadron event by applying a tagging 
counter hit, no charged particle before the target, charged particles 
after the target, no signal in the AC, and at least one hit on the TOF wall.
AC fires for electrons and positrons, and for pions with momentum 
higher than 0.6 GeV/c by the choice of a refractive index of 1.03.
A typical trigger rate was about 20 events per second.
The data taking was carried out during December, 2000 to June, 2001. 
\vspace{5mm}
\begin{center}
{\large \bf DATA ANALYSIS}
\end{center}

\begin{wrapfigure}{R}{6.5cm}
\vspace{-6mm}
\hspace{3mm}
\mbox{\epsfig{figure=yof4.eps,width=5.5cm}}

{\small{Figure 4.} Vertex position for $K^+K^-$ events along the 
photon beam direction. Arrows indicate the cut position for SC 
or LH$_2$ events. SC events were used for exotic state search.}

\end{wrapfigure}

From the total amount of $4.3 \times 10^7$ triggers, $8.0 \times 10^3$ 
events with a $K^+K^-$ pair were reconstructed. Data reduction was carried out 
in the following scheme.\\
\ 
\\
(1) Vertex position cut

The SC, which was used as a neutron target for the search 
of  $\Theta^+$, was a 0.5 cm thick plastic scintillator (polystyrene) 
and was placed at 9.5 cm downstream of LH$_2$. 
$K^+K^-$ pair events from the SC were identified by selecting 
vertex position along beam direction. Events that originate from 
a reaction in the SC were clearly seen in Fig. 4.
Events from maximum photon energy region above 2.35 GeV 
were omitted in consideration of increasing background 
contribution to the signal with increasing energy.
These cuts reduced the data sample to $3.2 \times 10^3 K^+K^-$ events.
\\
(2) Missing mass cut
\begin{wrapfigure}{R}{7cm}
\vspace{-5mm}
\hspace{3mm}
\mbox{\epsfig{figure=yof5.eps,width=6.5cm}}

{\small{Figure 5.} Invariant $K^+K^-$ mass distributions for the SC events. 
$\phi$ meson contributions were cut for exotic state search as indicated by arrows.}

\end{wrapfigure}

In the reaction $\gamma N \rightarrow K^+ K^- X$, $M_X$ was 
required to be nucleon and the rest of carbon nucleus be spectator.
The missing mass $MM_{\gamma K^+K^-}$ in the above reaction 
was calculated by assuming a qusi-free $\gamma N$ scattering. 
A total of $1.8 \times 10^3$ events survived after applying 
$0.90 < MM_{\gamma K^+K^-} < 0.98$ GeV/$c^2$.
\\
(3) $\phi$ meson cut

Most of the remaining $K^+K^-$ events (~85\%), which were 
from $\phi$ meson photoproduction and were uninteresting 
events in this report, were cut by applying 
$1.00 < M(K^+K^-) < 1.04$ GeV/$c^{2}$ as in Fig. 5.
\\
(4) Proton cut

$K^+K^-$ events, of which reactions were originated from 
protons, were eliminated by requiring SSD hit. The direction 
and momentum of the nucleon in the final state was calculated 
from the $K^+$ and $K^-$ momenta. Events were rejected if 
the recoiled nucleon was out of the SSD acceptance or was 
the momentum smaller than 0.35 GeV/c since an uncertainty 
in the calculation becomes large for low momentum case.
108 events were eliminated by requiring that the hit position 
in the SSD agreed with the expected hit position within 45 mm. 
This distance was chosen to take the Fermi motion in $^{12}$C into account.  
A total of 109 events satisfied all the selection criteria ("signal sample").
\begin{wrapfigure}{R}{7cm}
\vspace{-9mm}
\hspace{3mm}
\mbox{\epsfig{figure=yof6.eps,width=6.5cm}}

{\small{Figure 6.} The scatter plot of $MM_{\gamma K^+}$ 
$vs.$ $MM_{\gamma K^+\pi^-}$ for $K^+\pi^-$ photoproductions in the SC.
\vspace{2mm}
}

\end{wrapfigure}

A raw missing mass calculation done above was obtained 
without considering the Fermi motion in $^{12}$C. To evaluate 
this effect, well known process 
$\gamma n \rightarrow K^+\Sigma^- \rightarrow K^+\pi^-n$ was 
studied. Clear correlations are seen in the missing mass plots Fig. 6, where 
$MM_{\gamma K^+}$ and $MM_{\gamma K^+\pi^-}$ were obtained for 
the $\gamma N \rightarrow K^+X$ and $\gamma N \rightarrow K^+\pi^-N$ 
channels by assuming the nucleons at rest. This is understood by the 
fact that the nucleons in the two channels are identical. Considering the 
above missing mass correlation and setting the nucleon mass to $M_N$, 
the Fermi motion corrected missing mass $MM_{\gamma K^+}^c$ is obtained as
\begin{eqnarray}
MM_{\gamma K^+}^c = MM_{\gamma K^+} - MM_{\gamma K^+\pi^-} + M_N.
\end{eqnarray}
Eq. (2) compensates not only the Fermi motion but also the experimental 
resolutions and the binding energy of the nucleon in $^{12}$C. The Fermi 
motion effect is the major contribution in the analysis. 
Although there is only a smeared distribution in the raw 
$MM_{\gamma K^+}$ (dashed line in Fig.7), the 
$\Lambda$ and the $\Sigma^-$ peaks are separated after 
the correction (solid line in Fig.7). 
Note that this correction is not a good approximation for events 
with $MM_{\gamma K^+\pi^-}$ far from the nucleon rest mass, 
and is good in case of a decay with a small Q value. 
\setcounter{figure}{6}
\begin{figure}[t]
\centerline{\epsfxsize=2.7in\epsfbox{yof7.eps}}
\vspace{-5mm}
\caption{The corrected missing mass distribution 
$MM_{\gamma K^+}^c$ [Eq.(2)] for the $K^+\pi^-$ events from 
the SC (solid line) and for Monte Carlo events for the 
$\gamma n \rightarrow K^+\Sigma^-$ channel (dotted curve). 
The dashed line shows the missing mass distribution 
$MM_{\gamma K^+}$ which was obtained from the projection of the 
events in Fig. 6 on to the vertical axis without the Fermi-motion correction. 
\label{fig:sigma} }
\end{figure}
The latter effect is seen in the small width for the 
$\Lambda$ and the large width for the $\Sigma^-$ because of the 
imperfection of the correction due to a large Q value for the $\Sigma^-$.

The corrected missing mass $MM_{\gamma K^\pm}^c$  
for $K^+K^-$ events is given as
\begin{eqnarray}
MM_{\gamma K^\pm}^c = MM_{\gamma K^\pm} - MM_{\gamma K^+K^-} + M_N.
\end{eqnarray}


Fig. 8 shows no obvious peaks in a $MM_{\gamma K^+}^c$ 
distribution of the signal sample (109 events) that satisfied all 
the selection criteria (dotted line), and shows a clear peak due to the 
$\gamma p \rightarrow K^+\Lambda$(1520) $\rightarrow K^+K^-p$ 
process in the 108 events that agreed the proton hit in the SSD (solid line).
Effectiveness of a proton cut is verified that the $\Lambda$(1520) 
peak does not show up in the dotted line plot. 

\vspace{-4mm}
\begin{figure}[h]
\centerline{\epsfxsize=2.6in\epsfbox{yof8.eps}}
\vspace{-5mm}
\caption{The corrected missing mass distribution 
$MM_{\gamma K^+}^c$ [Eq.(3)] for the $K^+K^-$ productions for 
the signal sample (dotted line) and for events from the SC with a 
proton hit in the SSD (solid line).
\label{fig:sigma} }
\end{figure}

Fig. 9 shows the $MM_{\gamma K^-}^c$ distribution of the signal sample. 
A prominent peak at 1.54 GeV/$c^2$ is observed with 36 events in the 
peak region between 1.51 and 1.57 GeV/$c^2$. 
To estimate the background due to the non-resonant $K^+K^-$ 
production in the peak region defined above, 
the missing mass distribution of the signal sample in the 
region above 1.59 GeV/$c^2$ was fitted by a distribution of events 
from the LH$_2$. LH$_2$ sample required the same selection criteria 
except for the shifted $vtz$ window and a proton hit in the SSD.
Since the $\Lambda$(1520) contribution was removed from the signal 
sample, it was removed from LH$_2$ sample for 
$1.51 \leq MM_{\gamma K^+}^c < 1.53$ GeV/$c^2$.
The best fit with a $\chi^2$ of 7.2 for 8 degrees of freedom is obtained 
with a scale factor of 0.2 as shown with a dotted line in Fig. 9.
Resulting background level in the peak region is estimated to be 17.0 
$\pm$ 2.2 $\pm$ 1.8, 
where the first uncertainty is the error in the fitting in the region above 
1.59 GeV/$c^2$ and the second is a statistical uncertainty in the peak region. 
The combined uncertainty of the background level is $\pm$2.8. 
The estimated number of the signal events after subtracting 
background is 19.0 $\pm$ 2.8, which corresponds to a 
Gaussian significance of $4.6_{-1.0}^{+1.2} \sigma$ 
(19.0/$\sqrt{17.0} $). 
The signal region between 1.47 and 1.61 GeV/$c^2$ after background 
subtraction was compared with Monte Carlo simulations assuming a 
Breit-Wigner function for a resonance shape.
The best fit was 1.54 $\pm$ 0.01 (statistical) GeV/$c^2$. 
The systematic error was speculated to 0.005 GeV/$c^2$ by referring the 
known particle $\Sigma^-$, of which peak position was 0.005 GeV/$c^2$ 
smaller than the PDG value of 1.197 GeV/$c^2$. The width $\Gamma$ 
of the resonance cannot be determined by the fitting since the zero 
width gives the minimum $\chi^2$ of 1.6 for 4 degrees of freedom. 
The upper limit for the width was determined to be 0.025 GeV/$c^2$ 
with a confidence level of 90\%.
\vspace{-8mm}
\begin{figure}[h]
\centerline{\epsfxsize=4.2in\epsfbox{yof9.eps}}
\vspace{0mm}
\caption{The corrected missing mass distribution $MM_{\gamma K^-}^c$ 
[Eq.(3)] for the signal sample (solid line) and for events from the LH$_2$ 
(dotted line)  normalized by a hit in the region above 1.59 $GeV/c^2$.
\label{fig:sigma} }
\end{figure}
\\

To make sure that the observed peak is not due to a fake one, the mass 
cut on one of the kaons was tightened from 3 $\sigma$ to 2 $\sigma$, 
and also the kaon mass was intentionally assigned for the pions in the 
missing mass calculations. The peak was not affected in both cases, 
and it was also confirmed that the peak is not due to the effect of the 
tails of the $\phi$ mesons.

\vspace{6mm}
\begin{center}
{\large \bf DISCUSSION}
\end{center}

After we announced the evidence of $\Theta^+$, significant deal of 
activities have been reported in both experimental and theoretical fields.
Because of the peculiar nature and relatively small statistical 
significance of the new state, experimental confirmation was seriously 
awaited. Several experimental results appeared in succession from the 
DIANA collaboration at the ITEP~\cite{diana}, CLAS collaboration at the 
JLab~\cite{clas}, SAPHIR collaboration at the ELSA~\cite{saphir}, and a 
neutrino experiment~\cite{nu}. in all cases the mass is near 1.54 GeV/$c^2$ 
and the width is smaller than 0.025 GeV/$c^2$. There are informal announces 
of again consistent observations of $\Theta^+$ from HERMES and ZEUS. 
It is instructive that the DIANA collaboration reanalyzed almost 15 years 
old data which was obtained in the direct $s$-channel $K^+N$ 
measurements with $X_e$ bubble chamber. 

The most surprising point was the narrowness of the $\Theta^+$ 
width which is claimed to be smaller than 0.009 GeV/$c^2$~\cite{diana}. 
Recent partial wave analysis on $K^+N$ elastic scattering by Arndt, 
Strakovsky and Workman indicated that the width of $\Theta^+$ is likely 
smaller than 0.001 GeV/$c^2$~\cite{psa}. One of the speculation required 
$\Theta^+$ to be isotensor, and the isospin violating decay causes 
the narrow width~\cite{isot}. This explanation seems unlike if isospin 
of $\Theta^+$ is confirmed to be zero~\cite{saphir,iso0}. 

In fact we only know the $\Theta^+$ mass but not other quantum 
numbers. Spin and parity of $\Theta^+$ can be determined in 
principle by measuring the decay angular distribution and nucleon 
polarization as in the textbook. This is extremely difficult to do 
experimentally in straightforward way. To determine quantum 
numbers is our crucial task now on~\cite{qn1,qn2,qn3}. 

It is natural to ask whether $\Theta^+$ is a resonance or a 
baryon-meson molecular like state. It seems unusual to 
assume $\Theta^+$ to be a baryon-meson molecular state 
because of its narrow width according to Jaffe and Wilczek (JW)~\cite{jw}.

A discovery of the $\Theta^+$ was certainly guided by the prediction 
based on the chiral soliton model by DPP. On the other hand quark 
model approaches have been reported recently with highly correlated 
diquak-diquark~\cite{jw} and diquark-triquark~\cite{kl} schemes. If $\Theta^+$ 
mass is set to experimentally measured value of 1.54 GeV/$c^2$ in 
each model, expected exotic $\Xi$ mass is quite different between 
correlated quark model and chiral soliton model predictions. 
Exotic $\Xi$ mass is at 1.75 GeV/$c^2$ by a quark model of 
JW, although it is at 2.07 GeV/$c^2$ from eq.(1) with S = -2 by 
a chiral soliton model by DDP. DDP predicts the width to be 
greater than 0.14 GeV/$c^2$ in addition.
Recently reported observation of exotic $\Xi$ by NA49 collaboration 
indicates that the mass is at 1.862 GeV/$c^2$ with a width narrower 
than 0.018 GeV/$c^2$~\cite{exi}. The measured mass does not fit in 
any predictions, and Diakonov and Petrov proposes a revised model~\cite{dp}. 
There have been significant discoveries recently in meson spectroscopy 
field from the B-collider experiments. Unusually narrow meson states were 
observed in the BABAR, BELLE and other detectors~\cite{ds}. 
These states may be attributed to exotic tetraquark states. Further 
researches on the $\Theta^+$ and exotic $\Xi$ baryons together 
with the exotic mesons will boost in understanding the nature of the exotic states.

\vspace{6mm}
\begin{center}
{\large \bf CONCLUSION}
\end{center}

The LEPS measurement provides the first evidence for the existence of a 
S = +1 narrow baryon resonance at 1.54 $\pm$ 0.01 GeV/$c^2$ in the 
$K^-$ missing mass spectrum of the $\gamma n \rightarrow K^+K^-n$ 
reaction on $^{12}$C. The Gaussian significance is estimated to be 
4.6 $\sigma$ and the width is smaller than 0.025 GeV/$c^2$. The result 
is surprisingly coincided with the DPP's prediction.
This state is certainly an exotic baryon with a quark configuration of $uudd\bar{s}$.

\vspace{6mm}
\begin{center}
{\large \bf ACKNOWLEDGMENTS}
\end{center}

I am grateful to the organizers of Spin2003 for their invitation. I would like 
to thank Dr. Atsushi Hosaka for stimulating discussions on 
exotic states. This research was supported in part by the Ministry of 
Education, Science, Sports and Culture of Japan, by the National Science 
Council of Republic of China (Taiwan), and by KOSEF of Republic of Korea.

\vspace{6mm}
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\bibitem{nnpa}

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\bibitem{clas}

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\bibitem{nu}

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P. Page, hep-ph/0310200.

\bibitem{iso0}

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\bibitem{qn1}

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\bibitem{qn2}

Q. Zhao, hep-ph/0310350.

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\end{thebibliography}


\end{document}

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}}

\def\WF@floathand{%
\ifx\parshape\WF@fudgeparshape \WF@fltmes\else
  \ifx\par\@@par\ifnum\@@parshape=\z@\ifdim\hangindent=\z@
    \setbox\z@\lastbox \begingroup
    \@@par \WF@@everypar{}\WF@putfigmaybe
    \endgroup % start wrapping
    \ifvoid\z@\else\box\z@\fi % replace indentation
  \else\WF@fltmes\fi\else\WF@fltmes\fi\else\WF@fltmes\fi\fi}

% Put fig here if it fits or if it can't float
\def\WF@putfigmaybe{%
\ifinner
  \vskip-\parskip \global\WF@floatfalse
  \let\pagetotal\maxdimen % kludge flag for "not top of page"
\else % outer page
  \@tempdima\pagedepth % save page depth
   {\advance\parskip\@tempdima\vskip-\parskip}% back up to baseline
   \penalty\interlinepenalty % update pg. parameters
   \@tempdimb\pagegoal \advance\@tempdimb-\pagetotal % room left on page
   \ifdim\@tempdimb<\z@ % \WF@info{Page overfull already;}%
      \global\WF@floatfalse
      \ifdim-\@tempdimb>\pageshrink \else \pagebreak \fi
   \else
      \ifdim\WF@size>\@tempdimb
%        \WF@info{Size \the\WF@size\space does not fit in \the\@tempdimb}%
         \ifWF@float \dimen@.5\baselineskip \else \dimen@ 2\baselineskip\fi
         \ifdim\pagestretch>\dimen@ \dimen@\pagestretch \fi
         \ifdim\pagefilstretch>\z@ \dimen@\@tempdimb \fi
         \ifdim\pagefillstretch>\z@ \dimen@\@tempdimb \fi
         \advance\dimen@.5\baselineskip
         \ifdim\dimen@>\@tempdimb % \WF@info{Page nearly full; can stretch}%
            \global\WF@floatfalse \pagebreak
         \fi
      \else % \WF@info{Fits in \the\@tempdimb;}%
         \global\WF@floatfalse
   \fi\fi
   \vskip\@tempdima\relax % (return erased page depth)
\fi
\noindent
\ifWF@float
  \WF@fltmes
\else % putting here;
  \WF@info{Put \WF@wfname here:}%
  {\ifodd\if@twoside\c@page\else\@ne\fi % assign l/r to i/o placement
    \lccode`i`l\lccode`o`r\else \lccode`i`r\lccode`o`l\fi
    \xdef\WF@place{\the\lccode\lccode\WF@place}}% twice to get only l or r
  \hbox to\z@{% llap or rlap depending on {l} or {r}; calc effective width
   \@tempdima\wd\WF@box \@tempdimb\WF@ovh
   \advance\@tempdima-\@tempdimb \advance\@tempdima\columnsep
   \@tempdimb\hsize \advance\@tempdimb-\@tempdima
   \ifnum `l=\WF@place % fig on left
    \hss % figure overlaps space to the left
    \def\@tempa{\kern\columnsep}% position to left of the gap
   \else  %  fig on right
    \@tempdima\z@ % no left indentation
    \kern\@tempdimb \kern\columnsep
    \def\@tempa{\hss}% figure overlaps space to the right
   \fi
   \ifdim\@tempdimb<\hsize
    \xdef\WF@wrapil{\the\@tempdima \the\@tempdimb}% indentation and length
   \else
    \xdef\WF@wrapil{\z@ \the\hsize}%
   \fi
   \ifdim\pagetotal=\z@ % \WF@info{Put \WF@wfname at top of p.\thepage}%
    \global\advance\WF@size-\inmytextsep
   \else % \WF@info{Putting \WF@wfname in middle of page}%
    \setbox\WF@box\hbox{\lower\inmytextsep\box\WF@box}%
   \fi \dp\WF@box\z@ \box\WF@box \@tempa
  }% end \hbox to 0pt
  \aftergroup\WF@startwrapping % after the \endgroup which immediately
follows
\fi}

\def\WF@startwrapping{%
 \ifx\WF@wli\@empty
  {\advance\WF@size1.1\baselineskip
  \divide\WF@size\baselineskip \global\c@WF@wrappedlines\WF@size}%
 \else
  \setcounter{WF@wrappedlines}{\WF@wli}\global\advance\c@WF@wrappedlines\@ne
 \fi
 \ifnum\c@WF@wrappedlines>\@ne
  \let\parshape\WF@fudgeparshape \let\WF@pspars\@empty \let\WF@@par\par
  \def\@setpar##1{\def\WF@@par{##1}}\def\par{\@par}\let\@par\WF@mypar
  \xdef\WF@restoretol{\tolerance\the\tolerance}\tolerance9999
 \fi}

\def\WF@wraphand{%
\ifnum\c@WF@wrappedlines<\tw@ \WF@finale
\else \begingroup % Create \parshape command:
 \@tempcnta\@ne \let\WF@wrapil\relax \gdef\WF@ps{}%
 \@whilenum \@tempcnta<\c@WF@wrappedlines\do{% repeated indentation, length
  \xdef\WF@ps{\WF@ps\WF@wrapil}\advance\@tempcnta\@ne
 }\endgroup
 \ifx\WF@pspars\@empty
  \@@parshape\c@WF@wrappedlines \WF@ps \WF@noil
 \else % use external `parshape' values to modify my parshape
  \WF@modps
\fi\fi}

\def\WF@mypar{\relax
 \WF@@par % what the rest of LaTeX expects \par to be (usually \@@par)
 \ifnum\@@parshape=\z@ \let\WF@pspars\@empty \fi % reset `parshape'
 \global\advance\c@WF@wrappedlines-\prevgraf \prevgraf\z@
 \ifnum\c@WF@wrappedlines<\tw@ \WF@finale \fi}

\def\WF@modps{\begingroup
  \afterassignment\@tempdimb \@tempdima\WF@pspars % a=ind, b=wid
  \afterassignment\dimen@\advance\@tempdima\WF@wrapil
  \advance\@tempdimb\dimen@ \advance\@tempdimb-\hsize
  \def\WF@wrapil{\the\@tempdima \the\@tempdimb}%
  \edef\@tempb{\@@parshape\c@WF@wrappedlines \WF@ps \WF@pspars}%
  \expandafter\endgroup\@tempb}

\let\@@setpar\@setpar
\def\WF@noil{\z@ \hsize}
\let\WF@pspars\@empty

\def\WF@fudgeparshape{\relax \ifnum\c@WF@wrappedlines<\tw@ \WF@finale
  \else \afterassignment\WF@fudgeparshapee \fam \fi}
\def\WF@fudgeparshapee{\ifnum\fam=\@ne \expandafter \WF@parshapeee \else
  \WF@conflict \@@parshape\fam \fi}
\def\WF@parshapeee#1#2{\begingroup
  \delimitershortfall#1\nulldelimiterspace#2\edef\@tempa{%
   \def\noexpand\WF@pspars{\the\delimitershortfall
\the\nulldelimiterspace}}%
  \expandafter\endgroup\@tempa \WF@wraphand}

\def\WF@finale{\ifx\parshape\WF@fudgeparshape
 \WF@restoretol \let\@setpar\@@setpar \let\par\WF@@par
 \WF@info{Finish wrapping text}%
 \ifx\par\@@par \def\@par{\let\par\@@par\par}\else \let\@par\WF@@par \fi
 \let\parshape\@@parshape
 \parshape\ifx\WF@pspars\@empty \z@ \else \@ne \WF@pspars\fi \fi
 \ifvoid\WF@box \ifx\everypar\WF@everypar
  \let\everypar\WF@@everypar \everypar\expandafter{\the\WF@everypar}%
 \fi\fi}

\newcommand{\WFclear}{\ifvoid\WF@box\else \vskip\bigskipamount \box\WF@box
 \let\everypar\WF@@everypar \everypar\expandafter{\the\WF@everypar}%
 \fi \global\c@WF@wrappedlines\z@ \WF@finale}

\begingroup
 \toks0={\let\everypar\WF@@everypar \everypar\expandafter{\the\WF@everypar}%
   \let\parshape\@@parshape \let\@setpar\@@setpar }
 \toks1=\expandafter{\@arrayparboxrestore}
 \toks2=\expandafter{\clearpage}
 \edef\@tempa{\def\noexpand\@arrayparboxrestore{\the\toks0 \the\toks1}%
      \def\noexpand\clearpage{\noexpand\protect\noexpand\WFclear
\the\toks2}}
 \expandafter
\endgroup\@tempa

\def\WF@conflict{\WF@warning
 {\WF@wfname used inside a conflicting environment}}
\def\WF@collision{\WF@warning{Collision between wrapping environments}}
\def\WF@fltmes{\ifWF@float \WF@info{\WF@wfname floats}%
 \else \WF@warning{Stationary \WF@wfname forced to float}\fi}

\let\WF@warning\@warning
\let\WF@info\@gobble

\@ifundefined{DeclareOption}{\endinput}{}

\def\WF@warning{\PackageWarning{mywrapfig}}
\ProvidesPackage{mywrapfig}[1995/11/02 \space  v 3.1, HPT Tolsma]
\DeclareOption{verbose}{\def\WF@info{\PackageInfo{mywrapfig}}}
\ProcessOptions
\AtEndDocument{\WFclear}

\endinput

%%%%%  ----- End definitions ----- %%%%%

%%%%%  ----- Begin Instructions ----- %%%%%


W R A P F I G . S T Y  \ \  ver 3.1 \ \ (Nov 2, 1995)

Copyright (C) 1991,1992,1995 by Donald Arseneau  (asnd@Triumf.ca)

Wrapfig.sty provides the environments "wrapfigure" and "wraptable" for
typesetting a narrow float at the edge of the text, and making the text
wrap around it.  The "wrapfigure" and "wraptable" environments interact
properly with the "\caption" command to produce proper numbering, but
they are not regular floats like "figure" and "table", so (beware!) they
may be printed out of sequence with the regular floats.  There are four
parameters for "\begin{wrapfigure}", two optional and two required, plus
the text of the figure, with a caption perhaps:

   \begin{wrapfigure}[12]{r}[34pt]{5cm} <figure> \end{wrapfigure}
                      ==  =  ====  ===
   [number of narrow lines] {placement} [overhang] {width}

Some idiosyncrasies:

  - You must not specify a wrapfigure in any type of list environment or
    or immediately before or immediately after one.  It is OK to follow
    a list if there is a blank line ("\par") in between.

  - If you put a wrapfigure in a parbox or a minipage, or any other type
    of grouping, the text wrapping should end before the group does.

  - It does work in two-column format, but are your figures that small?

  - It may be out of sequence with regular floats.

  - The hlines that may be printed above and below floats are ignored;
    you must insert them manually if desired.

  - "\linewidth" is not adjusted within the wrapped text (because it can
    only be set for whole paragraphs at a time).  It is set within the
    figure.

\section{Placement and Floating}

Parameter "#2" (required) is the figure placement code, but the valid
codes are different from regular figures.  They come in pairs: an
uppercase version which allows the figure to float, and a lowercase
version that puts the figure ``exactly here''.

  r  R  -  the right side of the text
  l  L  -  the left side of the text
  i  I  -  the inside edge--near the binding (if "[twoside]" document)
  o  O  -  the outside edge--far from the binding

You should specify one code only, not a list.  The figure or table must
be on one side or the other; it cannot be in the middle with text on
both sides.  The "i" and "o" options refer to the inside and outside of
the whole page, not individual columns.

The ability to float is somewhat restricted, and you will get best results
by giving exact manual placement, but floating is more convenient while
revising the document.  Any changes to the formatting can ruin your manual
positioning so you should adjust the placement just before printing a
final copy.  Here are some tips for good placement:

  - The environment should be placed so as to not run over a page break.

  - The environment must not be placed in special places like lists.

  - Only plain text should wrap around the figure.  Section titles and
    big equations are bad; lists are bad if the figure is on the left.
    (These are legal, they just look poor.)  Small equations look fine.

  - It is convenient to begin the environment between paragraphs, but if
    you want placement in the middle of a paragraph, you must put the
    environment between two words where there is a natural line break.

When floating, \LaTeX\ tries to apply these rules.  More specifically,
a floated wrapping environment will only begin...

  - at the beginning of a paragraph,

  - when there is enough room on the page, or it is possible to go on
    the next page,

  - if the `paragraph' is not in a section title or a list,

  - if the paragraph is not wrapping around another figure,

  - in the main text (not in a minipage etc.)

It is possible that a non-floating wrapfigure will be forced to float
when an earlier one is still being processed.  A warning will be written
in that case.  You can have more information about the floating process
written to the log file by specifying "\usepackage[verbose]{wrapfig}".

If there is a lot of flexibility on a page, a floating wrapfigure may
be placed badly; you must turn to manual placement.  A rare problem is
that floats and footnotes specified within the wrapping text can also
cause poor placement and bad formatting.


\section {Sizing and optional overhang}

Parameter "#4" (the second required parameter) is the width of the figure
or table.  It is possible that the contents will be wider or narrower than
this value (if you use a tabbing environment or "\hbox") and the wrapped
text will use the greater of the specified and actual widths. \LaTeX\ will
wrap surrounding text around the figure, leaving a gap of "\inmytextsep" at
the top and bottom, and "\columsep" at the side, by producing a series of
shortened text lines beside the figure.  The indentation (shortening) of
the text is the figure width plus "\columnsep" minus overhang (if any; see
below).

\LaTeX\ calculates the number of short lines needed based on the height
of the figure and the length "\inmytextsep".  You can override this guess
by giving the first optional argument (parameter "#1") specifying the
number of shortened lines (counting each displayed equation as 3 lines).
This is particularly useful when the surrounding text contains extra
vertical spacing that is not accounted for automatically.

The second optional parameter ("#3") tells how much the figure should
hang out into the margin. The default overhang is given by the length
"\wrapoverhang", which is "0pt" normally but can be changed using
"\setlength".  For example, to have all wrapfigures use the space
reserved for marginal notes,

    \setlength{\wrapoverhang}{\marginparwidth}
    \addtolength{\wrapoverhang}{\marginparsep}

When you do specify the overhang explicitly for a particular figure, you
can use a special unit called "\width" meaning the width of the figure.
For example, "[0.5\width]" makes the center of the figure sit on the
edge of the text, and "[\width]" puts the figure entirely in the margin
(and the adjacent text is indented by just "\columnsep").


\section{Some Random Implementation Notes}

Unfortunately, \LaTeX's system of setting "\everypar" and "\par" is
unable to coexist peacefully with a wrapping environment, so I was
forced to subvert the "\@setpar" mechanism and "\everypar".  ("\everypar"
is already subverted once by NFSS.)

When checking the room left on the page, remember that if there is less
than "\baselineskip" the new paragraph will begin on the next page, even
if there is no page stretch. If non-floating, I force a bad page break
rather than have the figure hang into the bottom margin.

Here are notes on various variables and some macros; what info they
store and how they are used.

  \WF@wli - number-of-wrapped-lines parameter, saved for start of wrapping.
     Set globally by "\WF@wr" (set empty if no optional parameter given).
     The floating mechanism ignores this and uses the real size.

  \WF@ovh - margin overhang set globally by "\WF@rapt", saved until placing
     figure (but not reset).  Actually, the setting is very tricky so that
     the expected values are used when a figure floats. First, the
expression
     is saved without evaluation by "\WF@rapt" ("\begin{wrapfigure}")
because
     "\width" is still unknown.  Soon after that, "\endwrapfigure" executes
     "\WF@ovh" to evaluate the overhang and save the result (so that changes
     to "\wrapoverhang" while this figure is floating won't affect this
     figure). Finally, it is used by "\WF@putfigmaybe" when printing the
fig.

  \WF@place - a macro that is used as a number, giving the placement code.
     It might start out as "`I" and later be converted to "114" (r).

  \WF@box - tested for void at "\begin{wrapfigure}", to avoid collisions,
     by "\everypar" to do floating, and by "\WF@finale" before resetting
     "\everypar".  Voided globally when used by "\WF@putfigmaybe" (or by
     "\WF@wr" if an old figure must be dumped prematurely).

  \par - test if it is "\@@par" by "\begin{wrapfigure}" and "\WF@floathand"
     to float past special environments.  It is set to "\@par" ("\WF@mypar")
     by "\WF@startwrapping", and restored by an end-group (bad!) or by
     "\WF@finale" (good).  It is protected from change by redefining
     "\@setpar".

  \parshape - let to "\WF@fudgeparshape" by "\WF@startwrapping", so lists
     will continue wrapping; "\@@parshape" preserves the real "\parshape"
     command, and it is restored by "\WF@finale" or "\@parboxrestore".
     "\WF@floathand" and "\WF@wr" test if old wrapping is still in progress
     with "\ifx\parshape\WF@fudgeparshape". The value of "\@@parshape" is
     also tested to float past lists and other wrapping environments.

  \hangindent - tested to float past section titles etc.

  \c@WF@wrappedlines - the number of shortened lines + 1; set globally by
     "\WF@startwrapping" and decremented by "\par" ("\WF@mypar").  It is > 1
     only when wrapping is incomplete.  "\WF@wraphand", "\WF@fudgeparshape",
     and "\WF@mypar" test the number for calling "\WF@finale".  It may get
     stuck at some high value if "\par" is restored by an end-group, (and
     wrapping is terminated prematurely) so it is unwise to use this as a
     test for wrapping-complete.

  \pagetotal - one of many parameters used to compute floating.  When
     putting a wrapfigure in a parbox, I assign "\let\pagetotal\maxdimen"
     (locally!) to signal not-top-of-page and no floating.

  \WF@pspars - the "\parshape" parameters as LaTeX sets them for lists
     ("\WF@fudgeparshape"); when wrapping I test it and use it to modify my
     own real params for the paragraph.  They are also used when "\parshape"
     is restored after wrapping.

  \WF@finale - is performed by "\par" when wrapping should end.  However,
     that might happen inside a group (a list especially), so the subverted
     versions of "\par", "\parshape" etc. will be reinstated when the group
     ends.  Thus, they must themselves test "\c@WF@wrappedlines" < 2 to see
     when wrapping is over, and if so, they should just do "\WF@finale"
again.

These are the tests to see if a floating wrapfigure will fit at a particular
spot.  These tests are performed at the beginning of every paragraph after
the figure, except in lists etc.  ("\pagegoal" - "\pagetotal" is the room
left on the page.) 


  room_left := \pagegoal - \pagetotal
  if  room_left < 0  then page overfull already: put figure (on next page)
  else
     if  figure_size > room_left  then does not fit
        if  max(min_stretch, \pagestretch) + extra > room_left
           then page can stretch until full: put figure (at top of next
page)
        fi
     else figure fits: put figure
  fi fi
  <

Even if a wrapfigure is not floating, it will go through the same logic
to generate a "\pagebreak", and maybe an underfull page, when the current
page can stretch until full.  The "min_stretch" depends on whether it is
floating or not: ".5\baselineskip" (floating) "2\baselineskip" (not). The
"extra" is ".5\baselineskip" in either case.  These values can be adjusted.

There are some other `magic numbers' for floating that aren't really so
special, but you must change them together if you change them at all.
To make floating wrapfigures float less and fit on pages more frequently,
but not change the number of wrapped lines, decrease the "1.5" in
"\global\advance\WF@size1.5\baselineskip" and increase the "1.1" in
"\advance\WF@size1.1\baselineskip" by the same amount (and vice versa).
To make more (or fewer) wrapped lines for the same size figure, without
changing the floating, change "1.1" in "\advance\WF@size1.1\baselineskip"
unilaterally.

%%%%%  ----- End Instructions ----- %%%%%

Test file integrity:  ASCII 32-54, 55-126:  !"#$%&'()*+,-./0123456789
:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}�P




hep-ex0402005.extracted_bib
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