%
% $Id: aipcheck.tex,v 1.7 2002/01/11 19:50:46 frank Exp $
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Testing for potential problems with this class
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\newif\ifproblem
\newif\iftimesok

\makeatletter
\def\IfStandaloneCheck{\def\next{aipcheck}
  \edef\currjob{\jobname}
  \edef\next{\meaning\next}
  \edef\currjob{\meaning\currjob}
  \ifx\currjob\next
    \expandafter\@firstoftwo
  \else
    \expandafter\@secondoftwo
  \fi
}
\makeatother

\typeout{***********************************************}
\typeout{*}
\typeout{* Testing if all files required for the aipproc}
\typeout{* class are available ...}
\typeout{*}
\typeout{***********************************************}

\typeout{*}
\typeout{* Looking for LaTeX2e ... }
\ifx\documentclass\undefined
 \typeout{*}
 \typeout{* Sorry this is a fatal error:}
 \typeout{*}
 \typeout{* The aipproc class can only be used with LaTeX2e which is}
 \typeout{* the standard LaTeX since 1994!}
 \typeout{*}
 \typeout{* Please make sure that your version of LaTeX is up-to-date}
 \typeout{* before attempting to use this class.}
 \typeout{*}
 \expandafter\stop
\else
 \typeout{* ... ok }
\fi


\def\next#1/#2/#3\next{#1#2}
\typeout{*}
\typeout{* Testing that LaTeX2e is not too old ... }
\ifnum\expandafter\next\fmtversion\next<199612 \relax
 \typeout{* ... what a vintage! }
 \typeout{*}
 \typeout{* Sorry this is a fatal error:}
 \typeout{*}
 \typeout{* The aipproc class can only be used with a recent version}
 \typeout{* of LaTeX2e. Your version is dated \fmtversion\space --- but}
 \typeout{* at least the 1996/12/01 version is required!}
 \typeout{*}
 \typeout{* Please make sure that your version of LaTeX is up-to-date}
 \typeout{* before attempting to use this class.}
 \typeout{*}
 \expandafter\stop
\else
 \ifnum\expandafter\next\fmtversion\next<199806 \relax
   \typeout{* ... probably ok }
   \typeout{*}
   \typeout{* Your version of LaTeX2e is quite old --- the aipproc class}
   \typeout{* hasn't been tested with your release.}
   \typeout{*}
   \typeout{* We believe that it will probably work, but if you encounter}
   \typeout{* problems you will need upgrade your installation.}
   \typeout{*}
   \typein{* Type <return> to continue ...}
   \problemtrue
 \else
   \typeout{* ... ok }
 \fi
\fi


\typeout{*}
\typeout{* Looking for aipproc.cls ... }
\IfFileExists{aipproc.cls}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* Before you can use the aipproc class you have to unpack}
     \typeout{* it from the documented source.}
     \typeout{*}
     \typeout{* Run LaTeX on the file 'aipproc.ins', e.g.,}
     \typeout{*}
     \typeout{* \space\space latex aipproc.ins}
     \typeout{*}
     \typeout{* or whatever is necessary on your installation to process}
     \typeout{* a file with LaTeX. This should unpack a number of files for you:}
     \typeout{*}
     \typeout{* aipproc.cls \space and \space aip-*.clo}
     \typeout{*}
     \typeout{* After that retry processing this guide.}
     \typeout{*}
     \stop
}

\typeout{*}
\typeout{* Looking for aipxfm.sty ... }
\IfFileExists{aipxfm.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The aipxfm.sty file which is part of the aipproc distribution}
     \typeout{* must be installed in a directory which is searched by LaTeX.}
     \typeout{*}
     \typeout{* Please install this file and retry.}
     \typeout{*}
     \stop
}

\typeout{*}
\typeout{* Looking for aip-8s.clo ... }
\IfFileExists{aip-8s.clo}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The aip-8s.clo file which is part of the aipproc distribution}
     \typeout{* must be installed in a directory which is searched by LaTeX.}
     \typeout{*}
     \typeout{* Please install this file and retry.}
     \typeout{*}
     \stop
}

\typeout{*}
\typeout{* Looking for aip-8d.clo ... }
\IfFileExists{aip-8d.clo}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The aip-8d.clo file which is part of the aipproc distribution}
     \typeout{* must be installed in a directory which is searched by LaTeX.}
     \typeout{*}
     \typeout{* Please install this file and retry.}
     \typeout{*}
     \stop
}


\typeout{*}
\typeout{* Looking for aip-6s.clo ... }
\IfFileExists{aip-6s.clo}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The aip-6s.clo file which is part of the aipproc distribution}
     \typeout{* must be installed in a directory which is searched by LaTeX.}
     \typeout{*}
     \typeout{* Please install this file and retry.}
     \typeout{*}
     \stop
}


\typeout{*}
\typeout{* Looking for aip-arlo.clo ... }
\IfFileExists{aip-arlo.clo}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The aip-arlo.clo file which is part of the aipproc distribution}
     \typeout{* must be installed in a directory which is searched by LaTeX.}
     \typeout{*}
     \typeout{* Please install this file and retry.}
     \typeout{*}
     \stop
}

\typeout{*}
\typeout{* Looking for fixltx2e.sty ... }
\IfFileExists{fixltx2e.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found, trying fix2col.sty instead ... }
     \typeout{*}
     \IfFileExists{fix2col.sty}
	 {
	  \typeout{* ... ok }
	 }
	 {
	  \typeout{* ... not found! }
	  \typeout{*}
	  \typeout{* Sorry this is a fatal error:}
	  \typeout{*}
	  \typeout{* Your LaTeX distribution contains neither fixltx2e.sty}
	  \typeout{* nor fix2col.sty.}
	  \typeout{*}
	  \typeout{* This means that it is either too old or incompletely}
	  \typeout{* installed.}
	  \typeout{*}
	  \typeout{* fixltx2e.sty is part of the standard LaTeX distribution}
	  \typeout{* since 1999; fix2col.sty is an earlier version of this}
	  \typeout{* package.}
	  \typeout{*}
	  \typeout{* Best solution is to get the latest LaTeX distribution.}
	  \typeout{* If this is impossible for you, download fix2col.sty.}
	  \typeout{* You can get this software from a CTAN host.}
          \typeout{* Refer to http://www.ctan.org and search for "fix2col".}
	  \typeout{*}
	  \typeout{* After you have updated your LaTeX distribution}
	  \typeout{* retry processing this guide.}
	  \stop
     }
}

\typeout{*}
\typeout{* Looking for fontenc.sty ... }
\IfFileExists{fontenc.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The fontenc package, which is part of standard LaTeX}
     \typeout{* (base distribution) has to be installed at the site to}
     \typeout{* run the aipproc class.}
     \typeout{*}
     \typeout{* The fact that it cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* improperly.}
     \typeout{*}
     \typeout{* Please make sure that your version of LaTeX is okay}
     \typeout{* before attempting to use this class. The LaTeX distribution}
     \typeout{* contains the file "ltxcheck.tex" which can be used to}
     \typeout{* test the basic functionality and integrity of your installation.}
     \typeout{*}
     \stop
    }

\typeout{*}
\typeout{* Looking for calc.sty ... }
\IfFileExists{calc.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Sorry this is a fatal error:}
     \typeout{*}
     \typeout{* The calc package, which is part of standard LaTeX}
     \typeout{* (tool distribution) has to be installed at the site}
     \typeout{* to run the aipproc class.}
     \typeout{*}
     \typeout{* The fact that it cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts.}
     \typeout{*}
     \typeout{* Please make sure that the tools distribution of LaTeX}
     \typeout{* is installed before attempting to use this class.}
     \typeout{*}
     \typeout{* (You might be able to get calc.sty separately for your}
     \typeout{* installation if you are unable to upgrade to a recent}
     \typeout{* distribution for some reason.)}
     \typeout{*}
     \stop
    }

\typeout{*}
\typeout{* Looking for varioref.sty ... }
\IfFileExists{varioref.sty}
    {
     \typeout{* ... ok }
     \gdef\variorefoptionifavailable{varioref,}
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Problem detected:}
     \typeout{*}
     \typeout{* The varioref package, which is part of standard LaTeX}
     \typeout{* (tool distribution) is not installed at this site.}
     \typeout{*}
     \typeout{* The fact that it cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts.}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you cannot make use of the options "varioref" or "nonvarioref".}
     \typeout{*}
     \typeout{* Please also note that the aipguide.tex documentation}
     \typeout{* normally uses the "varioref" option to show its}
     \typeout{* effects (which  will now fail).}
     \typeout{*}
     \typein{* Type <return> to continue ...}
     \problemtrue
     \gdef\variorefoptionifavailable{}
     \let\vpageref\pageref
     \let\vref\ref
    }

\typeout{*}
\typeout{* Looking for times.sty ... }
\IfFileExists{times.sty}
    {
     \begingroup
% load times and forget it immediately again
       \RequirePackage{times}
       \global\expandafter\let\csname ver@times.sty\endcsname\relax    
       \long\def\next{ptm}
       \ifx\rmdefault\next
         \typeout{* ... ok }
         \gdef\psnfssproblemoption{}
         \endgroup
         \timesoktrue
       \else
         \endgroup
     \typeout{* ... obsolete! }
     \typeout{*}
     \typeout{* Serious problem detected:}
     \typeout{*}
     \typeout{* The times package, which is part of standard LaTeX}
     \typeout{* (psnfss distribution) is obsolete at this site.}
     \typeout{*}
     \typeout{* The fact that it contains incorrect code either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts with old files remaining!}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but}
     \typeout{* you have to specify the option "cmfonts" which result in}
     \typeout{* documents which are not conforming to the AIP layout specification!}
     \typeout{*}
     \typeout{* You can also try using the class in the following way:}
     \typeout{*}
     \typeout{* \space\space \string\documentclass[cmfonts]{aipproc}}
     \typeout{* \space\space \string\usepackage{times}}
     \typeout{* \space\space ...}
     \typeout{*}
     \typeout{* With luck this will result in Times Roman output but chances}
     \typeout{* are that you will get a larger number of error messages in}
     \typeout{* which case you have to remove the \string\usepackage declaration.}
     \typeout{*}
     \typein{* Type <return> to continue ...}
          \problemtrue
          \gdef\psnfssproblemoption{cmfonts}
          \def\textdegree{$^\circ$}            % used below but now
                                               % not setup
       \fi
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Serious problem detected:}
     \typeout{*}
     \typeout{* The times package, which is part of standard LaTeX}
     \typeout{* (psnfss distribution) can not be found.}
     \typeout{*}
     \typeout{* The fact that this package cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts!}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you have to specify the option "cmfonts" which result in}
     \typeout{* documents which are not conforming to the AIP layout specification!}
     \typeout{*}
     \typein{* Type <return> to continue ...}
     \problemtrue
     \gdef\psnfssproblemoption{cmfonts,}
    }

\iftimesok % don't bother testing other font options if times already
           % bad

\typeout{*}
\typeout{* Looking for t1ptm.fd or T1ptm.fd ... }
\IfFileExists{t1ptm.fd}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found, trying T1ptm.fd ... }
     \IfFileExists{T1ptm.fd}
          {
           \typeout{* ... ok }
          }
          {
           \typeout{* ... not found}
           \typeout{* Serious problem detected:}
           \typeout{*}
           \typeout{* The times package, which is part of standard LaTeX}
           \typeout{* (psnfss distribution) is available but the corresponding}
           \typeout{* .fd file (defining how to load Times Roman) is missing.}
           \typeout{*}
           \typeout{* The fact that this package is only partially installed}
           \typeout{* means that you LaTeX installation is unable to use Times}
           \typeout{* Roman fonts!}
           \typeout{*}
           \typeout{* You can use the aipproc class without this package but }
           \typeout{* you have to specify the option "cmfonts" which result in}
           \typeout{* documents which are not conforming to the AIP layout}
           \typeout{* specification!}
           \typeout{*}
           \typein{* Type <return> to continue ...}
           \problemtrue
           \timesokfalse
           \gdef\psnfssproblemoption{cmfonts,}
          }
    }

\fi


\newcommand\CheckFDFile[3]{%
  \typeout{*}
  \typeout{* Looking for #1#3.fd or #2#3.fd ... }
  \IfFileExists{#1#3.fd}
    {
     \typeout{* ... ok }
    }
    {
     \IfFileExists{#2#3.fd}
      {
       \typeout{* ... ok }
      }
      {\problemtrue
       \typeout{* ... not found! }
      }
    }
}

\iftimesok % don't bother testing other font options if Times already bad

%\CheckFDFile{ot1}{OT1}{ot1ztmcm}
%\CheckFDFile{oml}{OML}{omlztmcm}
%\CheckFDFile{oms}{OMS}{omsztmcm}
%\CheckFDFile{omx}{OMX}{omxztmcm}

\typeout{*}
\typeout{* Looking for mathptm.sty ... }
\IfFileExists{mathptm.sty}
    {
     \typeout{* ... ok }
     \CheckFDFile{ot1}{OT1}{ptmcm}
     \CheckFDFile{oml}{OML}{ptmcm}
     \CheckFDFile{oms}{OMS}{pzccm}
     \CheckFDFile{omx}{OMX}{psycm}
     \ifproblem
      \typeout{*}
      \typeout{* Problem detected:}
      \typeout{*}
      \typeout{* The mathptm package, which is part of standard LaTeX}
      \typeout{* (psnfss distribution) was found but some or all of its}
      \typeout{* support files describing which fonts to load are missing!}
      \typeout{*}
      \typeout{*}
      \typeout{* The fact that this package is only partially installed}
      \typeout{* means that the mathptm package cannot be used!}
      \typeout{*}
      \typeout{* You can use the aipproc class without this package but }
      \typeout{* you have to specify the option "nomathfonts" so that}
      \typeout{* math formulas will be typeset using Computer Modern.}
      \typeout{*}
      \typein{* Type <return> to continue ...}
      \problemtrue
      \gdef\psnfssproblemoption{nomathfonts,}
     \else
      \typeout{*}
      \typeout{* Looking for mathptmx.sty ... }
      \IfFileExists{mathptmx.sty}
       {
        \typeout{* ... ok }
        \CheckFDFile{ot1}{OT1}{ztmcm}
        \CheckFDFile{oml}{OML}{ztmcm}
        \CheckFDFile{oms}{OMS}{ztmcm}
        \CheckFDFile{omx}{OMX}{ztmcm}
        \ifproblem
	  \typeout{*}
	  \typeout{* Problem detected:}
	  \typeout{*}
	  \typeout{* The mathptmx package, which is part of standard LaTeX}
	  \typeout{* (psnfss distribution) was found but some or all of its}
	  \typeout{* support files describing which fonts to load are missing!}
	  \typeout{*}
	  \typeout{*}
	  \typeout{* The fact that this package is only partially installed}
	  \typeout{* means that the mathptmx package cannot be used!}
	  \typeout{*}
	  \typeout{* You can use the aipproc class without this package but }
	  \typeout{* you have to specify the option "mathptm" (no x) so that}
	  \typeout{* math formulas use the older version with upright greek letters.}
	  \typeout{*}
	  \typein{* Type <return> to continue ...}
	  \problemtrue
	  \gdef\psnfssproblemoption{mathptm,}
        \fi
       }
       {
	\typeout{* ... not found! }
	\typeout{*}
	\typeout{* Problem detected:}
	\typeout{*}
	\typeout{* The mathptmx package, which is part of standard LaTeX}
	\typeout{* (psnfss distribution) can not be found.}
	\typeout{*}
	\typeout{* This is unfortunate but not a disaster as the older}
	\typeout{* version of the package "mathptm" (no x) seems to exist.}
	\typeout{*}
	\typeout{* You can use the aipproc class without this package but }
	\typeout{* you have to specify the option "mathptm" so that}
	\typeout{* math formulas use the older version with upright greek letters.}
	\typeout{*}
	\typein{* Type <return> to continue ...}
	\problemtrue
	\gdef\psnfssproblemoption{mathptm,}
       }
      \fi
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Problem detected:}
     \typeout{*}
     \typeout{* The mathptm package, which is part of standard LaTeX}
     \typeout{* (psnfss distribution) can not be found.}
     \typeout{*}
     \typeout{* The fact that this package cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts!}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you have to specify the option "nomathfonts" so that}
     \typeout{* math formulas will be typeset using Computer Modern.}
     \typeout{*}
     \typein{* Type <return> to continue ...}
     \problemtrue
     \gdef\psnfssproblemoption{nomathfonts,}
    }

\typeout{*}
\typeout{* Looking for mathtime.sty ... }
\IfFileExists{mathtime.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* The mathime package can not be found.}
     \typeout{*}
     \typeout{* This is not a serious problem because this package is}
     \typeout{* only of interest if you own the commerical MathTime fonts.}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you cannot use the "mathtime" option of the class.}
     \typeout{*}
     \typein{* Type <return> to continue ...}
     \problemtrue
    }
\else
\fi % iftimesok

\typeout{*}
\typeout{* Looking for graphicx.sty ... }
\IfFileExists{graphicx.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Problem detected:}
     \typeout{*}
     \typeout{* The graphics package, which is part of standard LaTeX}
     \typeout{* (graphics distribution) can not be found.}
     \typeout{*}
     \typeout{* The fact that this package cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts!}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you cannot use commands like \protect\includegraphics
                or \protect\resizebox}
     \typeout{* in this case.}
     \typeout{*}
     \typeout{* Please note that you will get a further error message below}
     \typeout{* about: "graphicx.sty not found" because the class will try}
     \typeout{* to load this package! Type return in response to that error.}
     \typeout{*}
     \typeout{* As a result the illustrations in aipguide will look strange.}
     \typeout{*}
     \typein{* Type <return> to continue ...}

     \gdef\resizebox##1##2{}
     \gdef\includegraphics{\textbf{graphics package missing:}}
     \problemtrue
    }

\typeout{*}
\typeout{* Looking for textcomp.sty ... }
\IfFileExists{textcomp.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Problem detected:}
     \typeout{*}
     \typeout{* The textcomp package, which is part of standard LaTeX}
     \typeout{* (base distribution) can not be found.}
     \typeout{*}
     \typeout{* The fact that this package cannot be found either means that}
     \typeout{* this LaTeX release is too old or that it was installed}
     \typeout{* only in parts!}
     \typeout{*}
     \typeout{* You can use the aipproc class without this package but }
     \typeout{* you will always get the error: "textcomp.sty not found"}
     \typeout{* because the class will try to load this package!}
     \typeout{* Type return in response to that error.}
     \typeout{*}
     \typein{* Type <return> to continue ...}

     \def\textdegree{$^\circ$}         % used below but now
                                       % not set up
     \problemtrue
    }


\typeout{*}
\typeout{* Looking for url.sty ... }
\IfFileExists{url.sty}
    {
     \typeout{* ... ok }
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Problem detected:}
     \typeout{*}
     \typeout{* The url package, which should be part of a good LaTeX}
     \typeout{* distribution, can not be found.}
     \typeout{*}
     \typeout{* Without this package you will not be able to use the \string\url}
     \typeout{* command. Try to download this package from a CTAN  host.}
     \typeout{* Refer to http://www.ctan.org and search for "url".}
     \typeout{*}
     \typein{* Type <return> to continue ...}

     \problemtrue
    }


\makeatletter

\typeout{*}
\typeout{* Looking for natbib.sty ... }
\IfFileExists{natbib.sty}
    {
     \IfStandaloneCheck
       {\begingroup
        \let\@listi\relax
        \let\thebibliography\@empty
        \let\bibstyle\@empty
        \RequirePackage{natbib}
        \@ifpackagelater{natbib}{1999/05/29}
	  {
           \typeout{* ... ok }
	  }{
           \typeout{* ... might be too old! }
           \typeout{*}
           \typeout{* Your version of the natbib package might be too}
           \typeout{* old to be usable. This class was designed to}
           \typeout{* work with the version 7.0 dated 1999/05/28}
           \typeout{*}
           \typeout{* If problems occur download a}
           \typeout{* recent version from a CTAN host.}
           \typeout{*}
           \typeout{* Refer to http://www.ctan.org and search for "natbib".}
           \typeout{*}
           \typein{* Type <return> to continue ...}

           \global\problemtrue
	  }
        \endgroup
        }{}
    }
    {
     \typeout{* ... not found! }
     \typeout{*}
     \typeout{* Serious problem detected:}
     \typeout{*}
     \typeout{* The natbib package, which should be part of a good LaTeX}
     \typeout{* distribution, can not be found.}
     \typeout{*}
     \typeout{* Without this package you will not be able to use certain}
     \typeout{* citation styles. See the aipguide documentation!}
     \typeout{*}
     \typeout{* Especially the layout for ARLO requires this package!}
     \typeout{*}
     \typeout{* Try to download this package from a CTAN  host.}
     \typeout{* Refer to http://www.ctan.org and search for "natbib".}
     \typeout{*}
     \typein{* Type <return> to continue ...}

     \problemtrue
    }

\makeatother


\typeout{*}
\typeout{* ... finished testing}
\typeout{*}
\ifproblem
\typeout{* The tests have revealed some problems in your TeX installation.}
\typeout{*}
\typeout{* Please review the above comments carefully and read the file}
\typeout{* README for further information.}
\typeout{*}
\typeout{*****************************************************************}
\typein{* Type <return> to continue ...}
\else
\typeout{****************************************************************}
\typeout{*}
\typeout{* The tests have reveiled no problems in your TeX installation.}
\typeout{*}
\typeout{****************************************************************}
\fi


% if this file is run standalone stop otherwise continue

\makeatletter
\IfStandaloneCheck
 {
\typeout{*}
\typeout{* This document only produces terminal output.}
\typeout{*}
\stop
 }
 {
\AtBeginDocument{\relax\ifx\xfm@address@loop\@undefined
  \typeout{***************************}
  \typeout{* Oooops ... you seem to have picked up an obsolete}
  \typeout{* aipproc.cls file from a previous installation!}
  \typeout{*}
  \typeout{* Please check that LaTeX finds the right one.}
  \typeout{*}
  \typeout{* Sorry have to give up ....}
  \typeout{***************************}
  \stop
 \fi}
 }
\makeatother

\endinput
%%
%% This is file `template-6s.tex',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% template.raw  (with options: `6s')
%% 
%% Template for the LaTeX class aipproc.
%% 
%% (C) 1998,2000,2001 American Institute of Physics and Frank Mittelbach
%% All rights reserved
%% 
%%
%% $Id: template.raw,v 1.8 2002/06/02 15:34:15 frank Exp $
%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Please remove the next line of code if you
%% are satisfied that your installation is
%% complete and working.
%%
%% It is only there to help you in detecting
%% potential problems.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\input{aipcheck}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% SELECT THE LAYOUT
%%
%% The class supports further options.
%% See aipguide.pdf for details.
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\documentclass[
%%    ,final            % use final for the camera ready runs
  ,draft            % use draft while you are working on the paper
%%  ,numberedheadings % uncomment this option for numbered sections
%%  ,                 % add further options here if necessary
  ]
  {aipproc}

\bibliographystyle{unsrt}
% A useful Journal macro
\def\Journal#1#2#3#4{{#1} {\bf #2}, #3 (#4)}
% Some useful journal names
\def\NCA{ Nuovo Cimento}
\def\NIM{ Nucl. Instrum. Methods}
\def\NIMA{{ Nucl. Instrum. Methods} A}
\def\NPA{{ Nucl. Phys.} A}
\def\NPB{{ Nucl. Phys.} B}
\def\NPBproc{{ Nucl. Phys.} B(Proc. Suppl.)}
\def\NaHP{{ Nucl. Hadr. Phys.} A}
\def\PLB{{ Phys. Lett.}  B}
\def\PRL{ Phys. Rev. Lett.}
\def\PRD{{ Phys. Rev.} D}
\def\ZPC{{ Z. Phys.} C}
\def\EUPJ{{ Eur. Phys. J.} C} 
\def\JPG{{ J. Phys. G:} Nucl. Part. Phys.} 

\newcommand{\states}{{\hspace{-0.5em}
    \begin{array}{c}
      \scriptscriptstyle\rightarrow\\[-3.5mm]
      \scriptscriptstyle\leftarrow
    \end{array}\hspace{-0.5em}}}
\newcommand{\etal}{{\it et al.}}
\renewcommand\baselinestretch{1.}
\newcommand{\ba}{\begin{eqnarray}}
\newcommand{\ea}{\end{eqnarray}}
\newcommand{\baa}{\begin{eqnarray*}}
\newcommand{\eaa}{\end{eqnarray*}}
\newcommand{\bea}{\begin{eqnarray*}}
\newcommand{\eea}{\end{eqnarray*}}
\newcommand{\bm}[1]{\mbox{\boldmath $#1$}}
\newcommand{\bb}{\begin{thebibliography}}
\newcommand{\eb}{\end{thebibliography}}
\newcommand{\Ds}{\displaystyle}
\newcommand{\ci}[1]{\cite{#1}}
\newcommand{\bit}[1]{\bibitem{#1}}


\newcommand{\ttbs}{\char'134}
\newcommand{\AmS}{{\protect\the\textfont2
  A\kern-.1667em\lower.5ex\hbox{M}\kern-.125emS}}
\newcommand{\aiNN}{\scriptscriptstyle a_{1}NN}
\newcommand{\aipp}{\scriptscriptstyle a_{1}pp}
\newcommand{\bi}{\scriptstyle b_{1}}
\newcommand{\biNN}{\scriptscriptstyle b_{1}NN}
\newcommand{\hi}{\scriptscriptstyle h_{1}}
\newcommand{\hiNN}{\scriptscriptstyle h_{1}NN}
\newcommand{\hit}{h_{1}(1170)}
\newcommand{\hitNN}{\scriptstyle h_{1}(1170)NN}
\newcommand{\eps}{\varepsilon}
\newcommand{\no}{\nonumber}
\newcommand{\nnn}{\nonumber}
\newcommand{\nn}{\nonumber \\}
\newcommand{\M}{{\cal M}}
\newcommand{\dela}{\delta q^a}
\newcommand{\dels}{\delta q^s}
\newcommand{\delv}{\delta q^v}
\newcommand{\talpha}{\tilde{\alpha}}
\newcommand{\tmu}{\tilde{\mu}}
\newcommand{\ai}{\scriptstyle a_{1}}
\newcommand{\lambdap}{\lambda^\prime}
\newcommand{\Lambdap}{\Lambda^\prime}
\newcommand{\bgi}{\begin{itemize}}
\newcommand{\eni}{\end{itemize}}
\newcommand{\ii}{\item[\color{red}$\bullet$]}
\newcommand{\gmnn}{g_{\mbox{$\scriptscriptstyle {\M N N}$}}}
\newcommand{\ep}{e^\prime}
\newcommand{\gp}{g^\prime}
\newcommand{\cf}{{\it cf.}}
\newcommand{\e}{{\rm e}}
\newcommand{\be}{\begin{eqnarray}}
\newcommand{\ee}{\end{eqnarray}}
\newcommand{\yp}{y^\prime}
\newcommand{\ypp}{y^{\prime\prime}}
\newcommand{\xp}{x^\prime}
\newcommand{\spr}{s^\prime}
\newcommand{\xpp}{x^{\prime\prime}}
\newcommand{\xppp}{x^{\prime\prime\prime}}
\newcommand{\dy}{(dy)}
\newcommand{\dw}{(dw)}
\newcommand{\dz}{(dz)}
\newcommand{\dzi}{(dz_1)}
\newcommand{\dzii}{(dz_2)}
\newcommand{\dxi}{(dx_1)}
\newcommand{\dxii}{(dx_2)}
\newcommand{\dyi}{(dy_1)}
\newcommand{\dyii}{(dy_2)}
\newcommand{\pp}{p^{\prime} }
\newcommand{\ppp}{p^{\prime\prime}}
\newcommand{\ppi}{p^{\prime}_{1} }
\newcommand{\ppii}{p^{\prime}_{2} }
\newcommand{\dx}{(dx)}
\newcommand{\dxp}{(dx^{\prime})}
\newcommand{\dxpp}{(dx^{\prime\prime})}
\newcommand{\dxppp}{(dx^{\prime\prime\prime})}
\newcommand{\dyp}{(dy^{\prime})}
\newcommand{\dypp}{(dy^{\prime\prime})}
\newcommand{\dslash}{\gamma\partial}
\newcommand{\Dslash}{D \hskip -0.7em /}
\newcommand{\Mslash}{M \hskip -0.7em /}
\newcommand{\Vslash}{V \hskip -0.7em /}
\newcommand{\vslash}{v \hskip -0.5em /}
\newcommand{\pslash}{\gamma p}
\newcommand{\Pslash}{P \hskip -0.5em /}
\newcommand{\omslash}{\omega \hskip -0.7em /}
\newcommand{\Aslash}{\gamma A}
\newcommand{\Bslash}{\gamma B}
\newcommand{\bAslash}{\gamma \bar{A}}
\newcommand{\bBslash}{\gamma \bar{B}}
\newcommand{\aslash}{{\cal A} \hskip -0.45em /}
\newcommand{\bslash}{{\cal B} \hskip -0.6em /}
\newcommand{\Q}{{\cal Q}}
\newcommand{\T}{{\cal T}}
\newcommand{\HH}{{\cal H}}
\newcommand{\V}{{\cal V}}
\newcommand{\PP}{{\cal P}}

\newcommand{\tr}{{\rm tr}}
\newcommand{\se}{{\mathsf{\epsilon}}}
\newcommand{\cq}{{{\mathsf{q}}_1\cdot{\mathsf{q}}_2}}
\newcommand{\wq}{{{\mathsf{q}}_1\bbox{\times}{\mathsf{q}}_2}}
\newfont{\fib}{cmfi10 at 10pt}
\newcommand{\ps}{\mbox{\fib{s}}}
\newcommand{\pt}{\mbox{\fib{t}}}
\newcommand{\ce}{{\mathsf{c}}}
\newcommand{\tpt}{\tilde{\mathsf\pt}}
\newcommand{\nx}{\bbox{n}\cdot\bbox{x}}
\newcommand{\Tr}{{\rm Tr}}
\newcommand{\Det}{{\rm Det}}
\newcommand{\La}{{\cal L}}
\newcommand{\A}{{\cal A}}
\newcommand{\B}{{\cal B}}
\newcommand{\bA}{{\bar{A}}}
\newcommand{\bB}{{\bar{B}}}
\newcommand{\tD}{{\tilde{D}}}
\newcommand{\tA}{\tilde{A}}
\newcommand{\tB}{\tilde{B}}
\newcommand{\D}{{\cal D}}
\newcommand{\N}{{\cal N}}
\newcommand{\J}{{\cal J}}
\newcommand{\K}{{\cal K}}
\newcommand{\W}{{\cal W}}
\newcommand{\ie}{{\it i.e.}\ }
\newcommand{\eg}{{\it e.g.}\ }
\newcommand{\hwf}{{{\cal H}_{lh}^{a}}}
\renewcommand{\thefootnote}{\arabic{footnote}}
\newcommand{\fg}{\hspace{.1cm}^{\ast}F}
\newcommand{\jg}{\hskip .05cm ^{\ast}\hskip -.07cm j}
\newcommand{\Jg}{\hskip .05cm ^{\ast}\hskip -.07cm J}
\newcommand{\Gg}{\hspace{.1cm}^{\ast}G}
\newcommand{\da}{\left[{\rm d}\A\right]}
\newcommand{\dbpsi}{\left[{\rm d}\bar{\psi}\right]}
\newcommand{\dpsi}{\left[{\rm d}\psi\right]}
\newcommand{\dbchi}{\left[{\rm d}\bar{\chi}\right]}
\newcommand{\dchi}{\left[{\rm d}\chi\right]}
\newcommand{\dphi}{\left[{\rm d}\phi\right]}
\newcommand{\dphip}{\left[{\rm d}\phi^\prime\right]}
\newcommand{\TxI}{{\rm T}^{\infty}_x\, }


\layoutstyle{6x9}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% FRONTMATTER
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

\title{Transversity in Exclusive and Inclusive Processes}


\author{Leonard Gamberg}{
  address={Division of Science,
Penn State-Berks Lehigh Valley College, Reading, PA 19610,
USA}
\footnote{
Supported by a Research Development
Grant, Penn State Berks. 
Based on talk given at $15^{\rm th}$
International Spin Physics Symposium (SPIN 2002), 9-14 September, 2002.}}

\author{Gary R. Goldstein}{
  address={Department of Physics
          and Astronomy, Tufts University,
           Medford, MA 02155, USA}
\footnote{Supported by the US Department
of Energy DE-FG02-29ER40702.}
}

\author{Karo A. Oganessyan}{
 address={INFN-Laboratori Nazionali di Frascati, Enrico Fermi 40,
  I-00044 Frascati, Italy}
  ,altaddress={DESY, Notkestrasse 85, 22603 Hamburg, Germany}
}


\begin{abstract}
Both meson photoproduction and semi-inclusive deep
inelastic scattering can potentially probe transversity
properties of the nucleon.  We explore how that potential can be
realized dynamically.  The role of rescattering in
both exclusive and inclusive meson production as a source
for single spin asymmetries is examined.
Using a dynamical model, we evaluate the spin independent $\cos 2\phi$
asymmetry associated with transversity of quarks inside unpolarized
hadrons, at HERMES kinematics.
We also explore the effects of rescattering on the 
transversity distribution of the nucleon.
\end{abstract}

\maketitle

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% MAINMATTER
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\subsection{Transversity}
\vskip-0.25cm
It is  well known that 
the  leading twist transversity distribution $h_1(x)$~\cite{jaffe91} 
and its first moment, the tensor charge, being  chiral
odd   cannot be accessed in deep inelastic scattering.
However, $h_1(x)$ can be probed when  at least two hadrons are
present, \eg Drell Yan~\cite{ralston79} or
semi-inclusive deep inelastic scattering (SIDIS). In the
latter process at leading twist, the property of quark transversity
can be measured via the azimuthal asymmetry
in the fragmenting hadron's momentum and spin distributions.
For example, spinless hadrons produced in
the so-called Collins asymmetry~\cite{cnpb92}
depend on the transverse momentum of quarks in the target, $k_T$,  
and fragmentation functions, $p_T$~\cite{kotz0}.  
Including transverse momentum
leads to an increase in the number of
leading twist distribution and fragmentation 
functions (\eg $h_{1T}(x,k_T), h_{1T}^\perp(x,k_T), H^{\perp}_1(z,p_T)$).
Allowing time reversal odd ($T$-odd) quark distribution 
functions~\cite{ANSL,cplb,mulders2},  
$h_1^\perp(x,k_T), \ f_{1T}^\perp(x,k_T)$
suggests they  enter the semi-inclusive  unpolarized momentum,
and polarized spin, asymmetries. 
That is, the distribution $f_{1T}^\perp(x,k_T)$ representing 
the number density of {\em unpolarized} quarks in transversely polarized
nucleons, maybe  entering the recent measurements of SSAs at
HERMES and SMC in semi-inclusive pion electroproduction~\cite{hermes}.
Alternatively, $h_1^\perp(x,k_T)$ which 
describes the transfer of  transversity to quarks inside unpolarized
hadrons may enter transverse momentum dependent asymmetries.
Beyond the $T$-odd properties, the existence of these distributions
are a signal of the {\em essential} role 
played by the intrinsic transverse quark
momentum and the corresponding angular momentum of quarks inside
the target and fragmenting hadrons  in these hard scattering processes.

Further insight into transversity has come from analyzing 
quark-target helicity flip 
amplitudes in deeply virtual Compton
scattering (DVCS)\cite{diehl}.  
%Written as 
%combinations of the generalized parton distribution, $H(x,\xi,t)$
%reduce in the forward limit to $h_1(x)$.  
Angular momentum conservation 
requires that helicity changes are
accompanied by transferring 1 or 2 units of 
orbital angular momentum; {\em again highlighting}
the essential role of intrinsic $k_{T}$ and
orbital angular momentum in determining transversity. 

\subsection{The Exchange Picture}
The interdependence of transversity on
quark {\em orbital} angular momentum and $k_{T}$
is more general than suggested in the above discussion 
on SSAs and the GPD analysis of
transversity. This behavior arises
in ref.~\cite{gamb_gold} where we study the
vertex function associated with the tensor charge
in exclusive meson production.
Again, angular momentum conservation results in  the transfer of
orbital angular momentum $\ell=1$ carried by the dominant
$J^{PC}=1^{+-}$
mesons  to compensate for the non-conservation of helicity across
the vertex.  Transverse momentum dependence arises from
the axial vector mesons that {\em dominate} the
tensor coupling (They are the $C$-odd -- $h_1$(1170), $h_1$(1380),
$b_1$(1235)).
These mesons are in the $\left(35\otimes \ell=1\right)$
multiplet of the
$SU(6)\otimes O(3)$ symmetry group that best represents the
mass symmetry among the low lying mesons.
Along with axial vector
dominance this symmetry results in the isoscalar and isovector
contribution to the tensor charge
{\small\be
\delta u(\mu^2) -\delta d(\mu^2)
=\frac{5}{6}\frac{g_A}{g_V}\frac{ M_{\ai}^2}{
M_{\bi}^2}\frac{\langle k_{T}^2\rangle}{ M_N M_{\bi}},
\quad \delta u(\mu^2)+\delta d(\mu^2)
=\frac{3}{5}\frac{M_{\bi}^2}{M_{\hi}^2}\delv .
\ee}
Each depends on two powers of the average intrinsic quark
momentum $\langle k_{T}^2\rangle$, because  the tensor couplings
involve helicty flips associated with  kinematic factors
of $3$-momentum transfer.
as required by angular momentum conservation.

The $k_{T}$ dependence can be understood on fairly general grounds
from the kinematics of the exchange picture
in exclusive pseudoscalar meson photoproduction. For large
$s$ and relatively small momentum transfer $t$ simple combinations of
the four helicity amplitudes involve definite parity exchanges.
The four independent helicity amplitudes can have
the minimum kinematically allowed powers,
{\small\be
f_1 = f_{1+,0+} \propto k_{T}^1 , \quad
f_2 = f_{1+,0-} \propto k_{T}^0 ,\quad
f_3 = f_{1-,0+} \propto k_{T}^2 , \quad
f_4 = f_{1-,0-} \propto k_{T}^1.  \nonumber
\ee}
However, in single hadron exchange (or Regge pole exchange)
parity conservation requires {\small $f_1 =\pm f_4 \quad {\rm and} \quad f_2 =\mp f_3$} for even/odd parity exchanges. These pair relations,
along with a single hadron exchange model,
force $f_2$ to behave like  $f_3$ for small
$t$. This introduces the $k_{T}^2$ factor into $f_2$. However for a
non-zero polarized target asymmetry  to arise there must be
interference between single helicity flip and non-flip and/or double
flip amplitudes. Thus this asymmetry must arise from rescattering
corrections (or Regge cuts or eikonalization or loop corrections) 
to single hadron exchanges. That is, one of the amplitudes in
{\small\be
P_y = \frac{2 Im (f_1^*f_3 - f_4^*f_2)}
{\sum_{j=1...4}|f_j|^2}
\ee}
must acquire a different phase.
In fact rescattering  reinstates $f_2 \propto k_{T}^0$ 
by integrating over loop $k_{T}$, which
effectively introduces a $\left< k_{T}^2 \right>$
factor~\cite{gold_owens}. This is true for the {\em inclusive process} 
as well, where only one final hadron is measured; a relative phase
in a helicity flip three body amplitude is required.
\subsection{Rescattering and SIDIS}
\vskip-.25cm
Recently a rescattering approach was applied to the calculation of
SSA in pion electroproduction, 
using a QCD motivated quark-diquark model of the 
nucleon~\cite{brodsky} (BHS).
In Ref.~\cite{ji,cplb} the rescattering effect
is interpreted as giving rise to the $T$-odd 
Sivers~\cite{sivers}  $f_{1T}^\perp$
function; the number density of unpolarized quarks in a transversely 
polarized target. 
Being $T$-odd, this asymmetry vanishes at
tree level. The important lesson beyond the model calculation, is that,
theoretically, final state interactions are essential for producing
non-zero SSAs. Furthermore, the phenomenological determination of quark
spin distributions can be disentangled from measurements of SSAs.

We have investigated the 
rescattering contributions to the transversity distribution $h_1(x)$ and
the $T$-odd function $h_1^\perp(x)$ 
and corresponding asymmetries in SIDIS.  Collins~\cite{cnpb92} 
considered one such process, the production of pions from 
transversely polarized quarks in a transversely polarized target.
The corresponding SSA involves the convolution of
the transversity distribution function and the $T$-odd fragmentation
function, $h_1(x)\star H_1^\perp(z)$~\cite{kotz,boer}. The 
transversity distribution function is  defined through the light-cone
quark distribution with gauge link indicated,
{\small\be
s_T^i\Delta f_T(x,k_{T})&=&{\frac{1} {2}}\sum_n
\int {\frac{d\xi^- d^2\xi_\perp }
  {(2\pi)^3}} e^{-i(\xi^- k^+-\vec{\xi}_\perp \vec{k}_\perp)} 
\langle P|\overline{\psi}(\xi^-,\xi_\perp)|n\rangle
\nn &&
\langle n|\left(-ie_1\int^\infty_0 A^+(\xi^-,0) d\xi^-
   \right)\gamma^+ 
\gamma^i\gamma^5\psi(0)|P\rangle  + {\rm h. c.},
\ee}
where $e_1$ is the charge of the struck quark and
$n$ represents intermediate diquark states. 
Integration over $q^\mu$, the gluon momentum 
we obtain
{\small\be
&&s_{T}^i\Delta
f_T(x,k_{T})=\frac{e_1e_2g^2}{2(2\pi)^4}
\frac{1-x}{\Lambda(k_T^2)}
\left\{\left(S^i_T\Big[\bigg(m+xM\bigg)^2+k_T^2\bigg]
+2k^i_{T}\mathbf{S}_T\cdot\mathbf{k}_T\right)\right.
\no \\
&&\times\frac{1}{k^2_T+\Lambda(0)^2
+\lambda_g^2}
\left(\ln\frac{\Lambda(k^2_T)}{\Lambda(0)}
+\ln\frac{k^2_T+\lambda^2_g}{\lambda_g^2}\right)
-\left.
\left(S^i_T k_T^2+2k_T^i\mathbf{S}_T\cdot\mathbf{k}_T
\right)
\frac{1}{k_T^2}\ln\frac{\Lambda(k^2_T)}
{\Lambda(0)}
\right\},
\ee}
where {\small $\Lambda(k_{T}^2) = k_{T}^2 +
x(1-x)\left(-M^2+\frac{m^2}{x} + \frac{\lambda^2}{1-x}\right).$}
The (Abelian) gluon mass (usually chosen at $\lambda_g\approx 1\ GeV$)
is indicative of $\chi SB$ scale and appears here to regulate the IR
divergence.  This one loop contribution constitutes the next order term in an 
eikonalization. The first part has the same nucleon spin dependent 
structure as a tree level model calculation (modified 
by the log terms) - it  is leading twist and a 
combination of $h_{1T}(x,k_{T})$ and $h_{1T}^{\perp}(x,k_{T})$. 
The second part has a different structure than tree level - it appears 
as a rescattering effect only. It is IR finite and, in this model, is
proportional to the one loop result for $f_{1T}^{\perp}$~\cite{ji}
and ${\cal P}_y$ in BHS. The ratio of $h_{1T}(x,k_{T})$
to $h_{1T}^{\perp}(x,k_{T})$ will differ from the tree level.
When combined with a measure of transversely polarized quarks, the
fragmentation function $H_1^{\perp}(z)$, the
integrated $h_1(x)$ 
will contribute to the observable weighted meson azimuthal asymmetry 
from a transversely polarized nucleon~\cite{kotz0,boer}.

As mentioned in the introduction, the 
$T$-odd structure function $h_1^\perp(x,k_{T})$ is of great
interest theoretically,  since it vanishes at tree level, and 
experimentally, since its determination does not involve polarized
nucleons. Repeating the calculation above {\em without
nucleon polarization} leads to the result~\cite{gold_gam}
\small\be
\frac{\varepsilon_{+-\perp j}k_{T j}}{M}h_1^\perp(x,k_{T})&=&
\frac{e_1e_2g^2}{2(2\pi)^4}
\frac{(m+xM)(1-x)}{\Lambda(k^2_T)}
\varepsilon_{+-\perp j}k_{Tj}
\frac{1}{k_T^2}\ln\frac{\Lambda(k^2_T)}{\Lambda(0)}.
\ee\normalsize
It is  leading twist and IR finite. 
Being $T$-odd it will appear in SIDIS observables 
along with $T$-odd fragmentation functions.
In particular, the following weighted semi-inclusive 
DIS cross section projects out a leading
$\cos2\phi$ asymmetry~\cite{boer}, 
\small
\begin{equation}
{\langle {\vert P^2_{h{\perp}} \vert \over {M M_h}} \cos2\phi \rangle}_{UU}= 
\frac{\int d^2P_{h\perp} {\vert P^2_{h\perp}\vert \over {M M_h}}
\cos 2\phi d\sigma}
{\int d^2 P_{h\perp} d\sigma} = 
\frac{{8(1-y)} \sum_q e^2_q h^{\perp(1)}_1(x) z^2 H^{\perp(1)}(z)}
{{(1+{(1-y)}^2)}  \sum_q e^2_q f_1(x) D_1(z)}
\label{ASY} 
\end{equation}
\normalsize
where the subscript $UU$ indicates unpolarized beam and 
target(Note: The non-vanishing 
$\cos2\phi$ asymmetry originating from kinematical and 
dynamical effects only appears at order $1/Q^2$~\cite{CAHN,kotz0,OABD}).
The functions $h_1^{\perp (1)}(x)$ and $H_1^{\perp (1)}(z)$ are the weighted
moments of the distribution and fragmentation functions 
\small
\be
h^{\perp(1)}_1(x) \equiv \int d^2k_T \frac{k^2_T}{2M^2} h^{T}_1(x,k_T),\quad
H^{\perp(1)}_1(z) \equiv z^2 \int d^2p_T \frac{k^2_T}{2M^2_h} 
H^{T}_1(z,-p_T).
\ee\normalsize
\begin{figure}[t]
\includegraphics[height=6.0 cm]{xdep_cos2.eps} 
\includegraphics[height=6.0 cm]{zdep_cos2.eps}
\caption{Left Panel: The \protect{${\langle \cos2\phi \rangle}_{UU}$} 
asymmetry for 
\protect{$\pi^+$} production 
as a function of \protect{$x$}. Right Panel:
The \protect{${\langle \cos2\phi \rangle}_{UU}$} asymmetry for 
\protect{$\pi^+$} production 
as a function of \protect{$z$}.}
\label{A}
\end{figure}
$k_T$, $p_T$,  are the transverse momentum of the quark
in the target proton, and fragmenting quark respectively
and $M$, $M_h$ are the mass of the target proton and produced hadron.
We evaluate the ${\langle \cos2\phi \rangle}_{UU}$ asymmetry obtained 
from the  approximation,
\small\be
{\langle \cos2\phi \rangle}_{UU} \approx {{M M_h} \over 
{\langle P^2_{h\perp} \rangle} } {\langle {{\vert P^2_{h\perp} \vert} 
\over {M M_h}} \cos2\phi \rangle}_{UU} 
\label{EXP}
\ee
\normalsize
in the  HERMES kinematic range corresponding to 
$1$ GeV$^2$ $\leq Q^2 \leq 15$ GeV$^2$, $4.5$ GeV $\leq E_{\pi} \leq 13.5$ 
GeV, $0.2 \leq z \leq 0.7$, $0.2 \leq y \leq 0.8$, and taking $\langle 
P^2_{h\perp} \rangle = 0.25$ GeV$^2$ as input. 
The Collins ansatz~\cite{cnpb92,kotz0} for the analyzing power of 
transversely polarized quark fragmentation 
function $H^{\perp(1)}_1(z)$, has been  adopted~\cite{OBDN}. 
For $D_1(z)$, the simple parameterization from Ref.~\cite{REYA} was used. 
In Fig\ref{A} the ${\langle \cos2\phi \rangle}_{UU}$ of 
Eq.(\ref{ASY}) for $\pi^+$ production on a proton target is presented 
as a function of $x$ and $z$, respectively. 
Using $\Lambda_{QCD}=0.2\ GeV$ and $\mu=0.8\ GeV$,
Fig.\ref{A} indicates that the $\cos2\phi$ asymmetry related to  
is large enough (about $8\%$) to be measured~\cite{ggprep}.  
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% BACKMATTER
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Conclusions}
\vskip-.5cm
The interdependence of intrinsic transverse
quark momentum and angular momentum conservation are intimately
tied with the  studies of transversity. 
This is demonstrated from
analyses of the tensor charge in the context
of the vector dominance approach to exclusive meson photo-production,
to SSAs in SIDIS\cite{gamb_gold}.  
In the study of the tensor charge we find
 $\left< k_{T}^2 \right>$ factor that appears in
rescattering models in meson photoproduction
where interference phenomena are 
non-zero due to rescattering.
In the case of unpolarized beam and target we have predicted at HERMES
energies the sizable $\cos2\phi$ asymmetry associated with the
asymmetric distributions of transversely polarized quarks inside
of unpolarized hadrons.
{\small
\subsubsection{Acknowledgements}\vskip-.25cm
L.G. thanks the organizers of SPIN 2002 for the invitation to present
this work. I also thank 
Daniel Boer, Dennis Sivers and Feng Yuan for useful discussions.}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% You may have to change the BibTeX style below, depending on your
%% setup or preferences.
%%
%% If the bibliography is produced without BibTeX comment out the
%% following lines and see the aipguide.pdf for further information.
%%
%% For The AIP proceedings layouts use 
\bibliographystyle{aipproc}   % if natbib is available
%\bibliographystyle{aipprocl} % if natbib is missing

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% You probably want to use your own bibtex database here
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\vskip-0.25
\bb{99}
\bibitem{jaffe91}
X.\ Artu and M.\ Mekhfi, Z. Phys. C45 (1990) 669;
R.\ L.\ Jaffe and X.\ Ji, Phys. Rev. Lett. 67 (1991) 552;
Nucl. Phys. B375 (1992) 527.
\bibitem{ralston79}
J. Ralston and D. E. Soper, Nucl. Phys. B152 (1979) 109.
\bit{cnpb92} J.C.~Collins, Nucl. Phys. B396, 161 (1993).
\bibitem{kotz0} A. M. Kotzinian, Nucl. Phys B441 (1995) 234.
\bit{ANSL} M. Anselmino and F. Murgia, Phys. Lett B442 (1998) 470;
M. Anselmino, V. Barone, A. Drago and F. Murgia, .
\bibitem{cplb} J. C. Collins, Phys. Lett. B536 (2002) 43.
\bibitem{mulders2} R. D. Tangerman and P. J. Mulders,
Phys. Lett. B352 (1995) 129; Phys. Rev. D51 (1995) 3357;
Nucl. Phys. B461 (1996) 197.
\bibitem{hermes} A. Airapetian {\it et al.}, Phys. Rev. Lett.
84 (2000) 4047; A. Bravar, Nucl. Phys. Proc. Suppl. 79
(1999) 520.
\bibitem{diehl} P. Hoodbhoy and X. Ji, Phys. Rev. D58 (1998) 054006;
M. Diehl, Eur. Phys. J. C19 (2001) 485.
\bibitem{gamb_gold} L. Gamberg and G. R. Goldstein, Phys.
Rev. Lett. 87 (2001) 242001.
\bibitem{gold_owens} G. R. Goldstein and J. F. Owens,
Phys. Rev. D7 (1973) 865; Nucl. Phys. B71 (1974) 461.
\bibitem{brodsky}
S. Brodsky, D.S. Hwang and I. Schmidt, Phys. Lett. B530 (2002) 99.
\bibitem{ji} X. Ji and F. Yuan, Phys. Lett. B543 (2002) 66; 
A.V. Belitsky, {\it et al.}, .
\bit{sivers} D. Sivers, Phys. Rev D 41 (1990) 83 ; Phys. Rev. D 43 (1991) 261.
\bibitem{kotz} A. M. Kotzinian and P. J. Mulders,
Phys. Lett. B406 (1997) 373.
\bibitem{boer} D. Boer and P. J. Mulders, Phys. Rev. D57 (1998) 5780.
\bibitem{gold_gam} G. R. Goldstein and L. Gamberg,
. 
\bit{CAHN} R.N. Cahn, Phys. Lett.  B78 (1978) 269; Phys. Rev. D40 (1989) 
3107. 
\bit{OABD} K.A.~Oganessyan, et.al., Eur. Phys. J.  C5 (1998) 681.
\bit{OBDN} K.A.~Oganessyan, N. Bianchi, E. De Sanctis, and 
W.D. Nowak, Nucl. Phys. A689 (2001) 784.
\bit{REYA} E.~Reya, Phys. Rep. 69 (1981) 195.  
\bibitem{ggprep} L. Gamberg, G. R. Goldstein and 
K.A.~Oganessyan,  in preparation.

\eb

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Just a reminder that you may have to run bibtex
%% All of it up to \end{document} can be removed
%% if you don't like the warning.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\IfFileExists{\jobname.bbl}{}
 {\typeout{}
  \typeout{******************************************}
  \typeout{** Please run "bibtex \jobname" to optain}
  \typeout{** the bibliography and then re-run LaTeX}
  \typeout{** twice to fix the references!}
  \typeout{******************************************}
  \typeout{}
 }

\end{document}

\endinput

