[BLAST_ANAWARE] Arenhoevel

From: Michael Kohl (kohlm@mit.edu)
Date: Wed Nov 19 2003 - 12:43:37 EST


Hi all, especially those who are interested in H. Arenhoevel's
calculations.

Professor Arenhoevel has shown me his script with which he is able to
produce calculations on any chosen grid of kinematical variables and to
e-mail it to a chosen person in an automized way. That's why he can do it
so fast. The grid density doesn't matter at all.

The grid of those calculations that we already have is quite coarse though
people may argue that the applied spline interpolation would work well. In
order to stand on safe ground, I would rather recommend to request new
calculations on a much finer grid of kinematical variables.
Prof. Arenhoevel encouraged us to ask for any grid of calculations that
appears useful to us.
So, I would like you to determine how fine a meaningful grid, and what
its extensions should be. Then we can request the calculations by email.

>From today, I will be away until Nov. 28, 2003.

Regarding the discussion about the target spin angle in the lab and cm
system: Prof. Arenhoevel confirmed that the spin angle referred to
as theta_d is always in the lab system, as is the case in the papers as
well as in preparing the experiment. The transformation only matters
internally in the calculation process when structure functions are
evaluated and combined to differential cross sections or asymmetries in
the cm frame.
In fact, for us Arenhoevel calculates only the f's, and these are not
functions of theta_d. Theta_d only occurs explicitly when combining f's to
build asymmetries or cross sections, and this is done by ourselves in the
lab system.

Regards,

  Michael

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