CIRCE2 structure completely screwed up

[Juergen Reuter]

Using CIRCE2 (not talking about polarized beam spectra) with polarized beams gives vanishing cross sections.

A possible input file is

process muonmuon  = e1,E1 => e2,E2
sqrts = 500 GeV
beams = e1,E1 => circe2 
beams_pol_density = @(1),@(-1)
beams_pol_fraction = 1.0,1.0
$circe2_file = "ilc500.circe"
$circe2_design = "ILC"
?circe2_polarized = false
integrate(muonmuon) {iterations = 10:50000,5:50000}

[Juergen Reuter]

Discussed this on the phone: will introduce a new flag that switches polarization on in the structure function.

[Juergen Reuter]

Ok, not the foggiest what this is is and where it comes from. It is NOT the sf_int quantum numbers, probably something funny. Won't do anything on this.

[Juergen Reuter]

There is no possiblity to use polarization, the following SINDARIN runs into a segmentation fault:

process muonmuon  = e1,E1 => e2,E2
sqrts = 500 GeV
beams = e1,E1 => circe2 
beams_pol_density = @(1),@(-1)
beams_pol_fraction = 0.8,0.3
$circe2_file = "teslagg_500_polavg.circe"
$circe2_design = "TESLA"
integrate(muonmuon) {iterations = 10:50000,5:50000}

[Juergen Reuter]

Furthermore the particles in the interaction seemed to be bypassed. One can even generate AA -> AA processes.

[Juergen Reuter]

This problem has to be solved until latest early next week..... (otherwise I cannot make any plots for the next talk)

[kilian]

Replying to jr_reuter:

This problem has to be solved until latest early next week..... (otherwise I cannot make any plots for the next talk)

Granted, will look. (PS: today is public holiday in NRW, won't be online later) W

[Juergen Reuter]

The problem seems to be the following (TO,WK please correct me if I'm wrong): CIRCE1 doesn't do polarization inside the beams, such that the polarization is given via helicity-dependent luminosities. Hence, polarization is set via the beams_pol constructor. CIRCE2, however, sets helicitiy luminosities, such that there is either no polarization or polarization fractions are directly given from the CIRCE2 beam spectrum. Switching beams_pol on in addition is wrong, and even results in a seg fault (this should be caught, however). Remains the case of a polarization averaged beam spectrum, where the user sets polarization by hand via beams_pol constructor. Up to now, this results in a zero cross section, as all the channel weights come out as zero. My guess is that one would have to have a polarization constructur in the circe2_init routine analogous to circe1_init in that case.

[kilian]

Reproduced, failed test is now in r7002

[kilian]

r7004: fixed. Allow user beam polarization for pol-averaged data file, with a warning. Disallow user beam polarization for polarized data file, because in that case the polarization is in the data.

[Juergen Reuter]

I still a segmentation fault with the following setup:

process muonmuon  = e1,E1 => e2,E2
sqrts = 500 GeV
beams = e1,E1 => circe2
beams_pol_density = @(1),@(-1)
beams_pol_fraction = 0.8,0.3
$circe2_file = "teslagg_500_polavg.circe"
# $circe2_file = "ilc500.circe"
$circe2_design = "TESLA"
?circe2_polarized = false
integrate(muonmuon) { iterations = 10:50000,5:50000}
sample_format = debug
n_events = 3
simulate (muonmuon)

[Juergen Reuter]

Ah, the reason for that is probably that the file teslagg_500_polavg.circe only contains photon luminosities and is indeed a photon collider spectrum. But that should be caught.

[kilian]

Replying to jr_reuter:

Ah, the reason for that is probably that the file teslagg_500_polavg.circe only contains photon luminosities and is indeed a photon collider spectrum. But that should be caught.

The sanity check was implemented but too late. Fixed in r7010.