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<A NAME=MSHELL>

<TITLE>MSHELL</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>MSHELL</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>command</B><P>
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The <em>mshell</em> command puts particles on the mass shell in high-energy 
physics calculations. 
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syntax: </H3>
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<em>mshell</em>&lt;vector-var&gt;{,&lt;vector-var&gt;}* 
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&lt;vector-var&gt; must have had a mass attached to it by a 
<A HREF=r37_0413.html>mass</A> 
declaration. 
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 <P> <H3> 
examples: </H3>
<P><PRE><TT>
vector v1,v2; 

mass v1=m,v2=q; 

mshell v1; 

v1.v1; 

   2
  M  


v2.v2; 

  V2.V2 


mshell v2; 

v1.v1*v2.v2; 

   2  2
  M *Q

</TT></PRE><P>Even though a mass is attached to a vector variable representing a
 
particle, the replacement does not take place until the <em>mshell</em> 
declaration is given for that vector variable. 
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