effect on flux from target z-position smearing · simulation parameters g4lbne with...
TRANSCRIPT
Effect on flux from target z-position smearing
Timur BeremkulovBIWG meeting 07/11/2019
MotivationProton beam
Graphite target
2
Pions, kaons Neutrinos
● To measure the oscillation angle with desired precision flux needs to be constrained within 1-2%
● Need to know upper bound on z-position measurement precision for NA-61/SHINE
Simulation Parameters
● g4lbne with OptimizedEngineedredNov2017.mac● 2*10^6 protons @ 120 GeV● Graphite target 2.2 m long
3
4
Nominal NuMu flux at far detector
5
● Get info about particles that exit the target● Scramble the z-position of particles● Feed them back into the simulation
● Two ways how scrambling was done:○ Gaussian smearing: Z_new = gaus(Z_old, sigma)○ Smearing within bins: break 2.2 m into N-1 bins + 1
downstream bin, if z_old is in bin M => Z_new = uniform(length of bin M)
6
Example of Target Exit Z position plot, with gaussian smearing, sigma = 50cm
7
8
Example of Target Exit Z position plot, with gaussian smearing, sigma = 5cm
Relative difference in flux for gaussian smearing
9
(Flux_before_smearing - Flux_after_smearing)/Flux_before_smearing
Energy, GeV
Example of Target Exit Z position plot, with gaussian smearing, N_bins = 5
10
11
Relative difference in flux for smearing within bins
Energy, GeV
Summary
● Effect of gaussian smearing and smearing within bins on NuMu flux at far detector were studied.
● Both methods show that z-position should be known within 10 cm.
12