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## LUMINOSITY

Define the transverse mesh size , number of bins, etc, for luminosity calculation. One luminosity command is needed for each combination of particles , e, e, right-going and left-going. Thus, there can be at most 9 LUMINOSITY commands. LUMINOSITY KIND=(,), [FREP=,] [W=(,[,]),] [E1=(,[,]), E2=(,[,]),] WX=([,]), WY=([,]), [HELICITY,] ;
,
Particle species of right and left-going beams.
Repetition frequency (Hz). Used for the luminosity scale only. Default=1Hz.
,,
Parameters for differential luminosity   with respect to the center-of-mass energy W. (,) is the range in eV and is the number of bins. If (,) is not given, the center-of-mass spectrum is not calculated. Default for is 50.
,,,,,
2-D differential luminosity . (, ) is the range in eV and is the number of bins. (j=1 for right-going beam and j=2 for left-going beam.) Both or none of E1 and E2 have to be specified. If none is specified, 2-D luminosity is not calculated. Default for is 50.
,
Full horizontal/vertical width of the mesh region (m). The origin is adjusted automatically from time to time.
,
Maximum width of the mesh region (m). If not given, is used throughout. If given, an increased size upto is used when a significant particle fraction gets out of the mesh region defined by . The number of mesh points is determined automatically.
HELICITY
Calculate luminosity for every combination of helicity, (++), (-+), (+-), (-).

All the LUMINOSITY commands must have the same value of ,,,, and . (Specify them at the first LUMINOSITY command.)

Note that the longitudinal mesh size, which is common to beam-beam field and luminosity calculations, has to be defined by the parameter Smesh  by the SET command.

The luminosity is actually computed by the PUSH-ENDPUSH loop. The calculated luminosity can be referred to by the following functions.   (If during the loop, the accumulated luminosity upto that moment is returned.)

Lum(,)
Luminosity of KIND=(,) in units of cmsec.
LumH(,,h)
Helicity luminosity : helicity combination (++) (h=1), (-+) (h=2), (+-) (h=3), (-) (h=4). h=0 will give the total luminosity Lum(,). (cmsec)
LumW(,,n)
Differential luminosity in the n-th bin.   (cmsec/bin)
LumWbin(,,n)
Bin center (eV) of the n-th bin. If n=0, the number of bins is returned. (Error if n<0 or n is larger than the number of bins.)
LumWH(,,n,h)
Differential helicity luminosity. (cmsec/bin)
LumEE(,,,)
2-D differential luminosity for the bin (,).
(cmsec/bin)
LumEEbin(,,l,n)
Bin center (eV) of the n-th bin of (l=1) or (l=2). If n=0, the number of bins is returned. (Error if n<0 or n is larger than the number of bins.)
LumEEH(,,,,h)
2-D differential helicity luminosity

These functions can be included in expressions. Thus, you can write the computed luminosity on a file. In particular, the only way to retrieve the 2-D luminosity is to use the above functions because PLOT LUMINOSITY command cannot plot it (KEK TopDrawer cannot draw 3-D plot). So, for example, to write ee luminosity,
S ET m1=LumEEbin(2,3,1,0), m2=LumEEbin(2,3,2,0);
W RITE ((LumEE(2,3,n1,n2),n1=1,m1),n2=1,m2),
F ORMAT=();

Next: PPINT Up: Commands Previous: EXTERNALFIELD

Toshiaki Tauchi
Thu Dec 3 17:27:26 JST 1998