<chapter name="Top Processes"> 
 
<h2>Top Processes</h2> 
 
Different ways to produce top quarks, singly or in pairs. 
 
<flag name="Top:all" default="off"> 
Common switch for the group of top production. 
</flag> 
 
<flag name="Top:gg2ttbar" default="off"> 
Scatterings <ei>g g &rarr; t tbar</ei>. 
Code 601. 
</flag> 
 
<flag name="Top:qqbar2ttbar" default="off"> 
Scatterings <ei>q qbar &rarr; t tbar</ei> by gluon exchange. 
Code 602. 
</flag> 
 
<flag name="Top:qq2tq(t:W)" default="off"> 
Scatterings <ei>q q' &rarr; t q''</ei> by <ei>t</ei>-channel exchange 
of a <ei>W^+-</ei> boson. 
Code 603. 
</flag> 
 
<flag name="Top:ffbar2ttbar(s:gmZ)" default="off"> 
Scatterings <ei>f fbar &rarr; t tbar</ei> by <ei>s</ei>-channel exchange 
of a <ei>gamma^*/Z^0</ei> boson. 
Code 604. 
</flag> 
 
<flag name="Top:ffbar2tqbar(s:W)" default="off"> 
Scatterings <ei>f fbar' &rarr; t q''</ei> by <ei>s</ei>-channel exchange 
of a <ei>W^+-</ei> boson. 
Code 605. 
</flag> 
 
<flag name="Top:gmgm2ttbar" default="off"> 
Scatterings <ei>gamma gamma &rarr; t tbar</ei>. 
Code 606. 
</flag> 
 
<flag name="Top:ggm2ttbar" default="off"> 
Scatterings <ei>g gamma &rarr; t tbar</ei>. 
Code 607 when <ei>g gamma &rarr; t tbar</ei> and 617 
when <ei>gamma g &rarr; t tbar</ei>. 
</flag> 
 
<p/> 
By default top always decays to a <ei>W</ei> and a down-type quark. 
It is possible to switch on the <ei>t &rarr; H+ b</ei> decay mode. 
Note that its partial width is calculated using the <ei>tan(beta)</ei> 
value stored in <code>HiggsHchg:tanBeta</code>, so that it can be used 
without having to read in a SUSY parameter file. For the <ei>H+</ei> to 
decay also <code>Higgs:useBSM = on</code> is necessary. 
 
</chapter> 
 
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