Scan over model parameters

Scan over a specified range of model parameters.

1. Running a Scan

First, you need to set up your model and process as usual. For example, if you want to scan over a simplified scalar dark matter model, you can do the following:

MadDM> import model eDMsimp_s_spin0
MadDM> define darkmatter xd
MadDM> generate direct
MadDM> output SCAN_example
MadDM> launch SCAN_example

At the launch prompt, set the parameters you want to scan, using set MXd scan: followed by a python array or range function. For instance, if you want to scan the dark matter mass (MXd) from 50 GeV to <700 GeV in steps of 25 GeV, you can do:

MadDM> set MXd scan:range(50,700,25)

If you want to scan only over some specific values, you can also use python arrays, as follows:

MadDM> set MXd scan:[0.01,0.02,0.04,0.10,0.20,0.4,0.8,1]

or you can use list comprehension. For example, to scan over a logarithmic scale from 10 MeV to 1 GeV you can do:

MadDM> set MXd scan:[10 ** (-2 + i * 0.2) for i in range(11)]

Then press Enter to start the scan. For scans, you will find in the output directory a run_XX_YY folder containing the maddm.out file for each YY iteration. You will also find a scan_run_XX.txt file that summarizes the scan parameters and results. You can also make a scan over multiple parameters at once. For example, if you want to scan over the dark matter mass MXd and the coupling ,``gsxd`` you can do:

MadDM> set MXd scan:[10 ** (-2 + i * 0.2) for i in range(11)]
MadDM> set gsxd scan:range(100,1000,100)

Then press Enter to start the scan. MadDM will generate one run for each combination of the parameters you specified, iterating first over the last parameter in the param_card.dat. Once all values of that parameter are exhausted, it steps the second-to-last parameter and repeats the process, and so on, like nested for loops, starting from the outermost (first) parameter to the innermost (last).

You will find the results of the scan in /SCAN_example/output/scan_run_01.txt. In this example, this file will contain the pvalues for XENON10 and XENON1T for each value of the dark matter mass and coupling you scanned.

Exiting MadDM

MadDM> quit