D. Rubin, S.Isaacman, A.Long
<br>March 21, 2005.
<p>
<h1>Pretzel dependence</h1>
<p>
<h3>Introduction</h3>
In the standard cesr-c optics, <a href="hibetainj_20040628_v01.html">
hibetainj_20040628_v01.lat</a>,
we find no significant effect of crossing angle, 
pretzel, and parasitic crossings on specific luminosity.
<p>
<h3> Model</h3>
In our machine model we set horizontal separators to
zero and exclude all parasitic beambeam interactions.
Vertical separation at L3 remains and beams are brought
into collision as usual using VNOSEING 1,2 and PRETZING 13.
<h3> Simulation </h3>
The simulated luminosity vs current with pretzel off
is <a href="../beambeam/270205-1_080105-1.gif"> plotted </a>
along with results with standard pretzel and 9X5 bunches. 
There is no significant difference. 
The number of the initial 200 macroparticles that are lost
during the course of the 100k turns as a function of bunch current
is shown <a href="../beambeam/lost_particles_270205-1_080105-1.gif"> here </a>.
The loss of a single particle corresponds to a lifetime of about 50 seconds.