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- Timestamp:
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Jan 6, 2019, 7:53:17 PM (6 years ago)
- Author:
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mosel
- Comment:
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v14
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v15
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39 | 39 | |
40 | 40 | == How to compute cross sections from the perturbative weights == |
41 | | The output file `FinalEvents.dat` contains all the events generated. Per event all the four-momenta of final state particles are listed together with the incoming neutrino energy and various other useful properties (see documentation for `FinalEvents.dat`). |
| 41 | The output file `FinalEvents.dat` contains all the events generated. Per event all the four-momenta of final state particles are listed together with the incoming neutrino energy, the 'perWeight' and various other useful properties (see documentation for `FinalEvents.dat`). In each event there is one nucleon with perweight=0 which represents the hit nucleon; for 2p2h processes the second initial nucleon is not written out. |
42 | 42 | |
43 | 43 | As an example we consider here the calculation of the CC inclusive differential cross section dsigma/dE_mu for a neutrino-induced reaction on a nucleus; E_mu is the energy of the outgoing muon. In `FinalEvents.dat` the lines with the particle number 902 contain all the muon kinematics as well as the perweight. In order to produce a spectrum one first has to bin the muon energies into energy bins. This binning process must preserve the connection between energy and perweight. Then all the perweights in a given energy bin are summed and divided by the bin width to obtain the differential cross section. If the GiBUU run used - for better statistics - a number of runs >1 at the same energies, then this number of runs has to be divided out to obtain the final differential cross section. |
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