Lepto parameters study
Problem: Real data shows the dependence on the nuclear target of the hadron transverse momentum pT2.
How to reproduce this dependence in simulation in order to make an acceptance correction ?
Fig.1 Transverse momentum squared distribution in the real data and simulated(generator output, not reconstructed) .
Parameter Tests
NOTE: distributions, corresponding to the parameters' settings in use correspond to the black curves through all the plots, the color shows the variation
1. Compare PDFs CTEQ2L and CTEQ2D (LST(15)):
2.Changing the primordial transverse momentum kT, using CTEQ2D (PARL(3)).
kT defualt value is 0.44(black), tried kTmin=0(green) and kTmax=2.5(red)
3. Changing the width of the Gaussian of transverse momentum rT of the target remnant (PARL(14)).
rT defualt value is 0.35 (black), the values tried are rT = 0.15, 0.7, 1. GeV.
4. Changing the scale in parton showers (LST(9)).
Default value is ~ dependence on pT2 for the x->0 and x->1.
Values tried are: ~pT2, ~x0W2 w/o non-perturbative part, ~W3/4 similar to color dipole cascade model
5. Changing the scale of Lamba_QCD (PARL(26)):
0.2(black) and 0.22 (green):
6. Inclusion of longitudial structure function(LST(11)):
Default is not included(black),inculsion (green).
7. Changing the scheme against cut-offs LST(20)+PARL(8&9):
8. Switching off(green) and on(black, blue) SCI (LST(34)):
9. Sea quark treatment: on(black) and off(green) (LST(35)) and on with different width of its virtuality(blue and red)(LST(35)+PARL(10)) :
10. Probabiltiy for SCI: 0.5(black), 0.1(green) and 0.9(blue)(PARL(7)):
11. Mass reduction for complex nuclei: 0.1(black), 0.01(green) and 0.8(blue):
12. Cut-off in the initial shower: 0.5 GeV(green) and 4. GeV(blue) (PYPAR(22)):
13.Cut-offs against divergencies in the matrix elements: min(green) and max(blue) (PARL(8) & PARL(9)).
Number of entries is different sine at min divergencies, it collapses:
14. Changing the specification for the first order QCD process (q-event, qg, qqbar):
15. Simulating very unphysical results
Left Plot: changing transverse primordial mom kT = 0.44(default), 5, 500 GeV
Right PLot: changing beam energy : E = 5.014 (default),6.3 , 7.4, 7.79 GeV