WC in flavio

[amrashed]

Hello,

In this example https://github.com/flav-io/flavio-examples/blob/master/Plots_of_q2_dependent_observables.ipynb in cell 6 you said that CV_buenu': 0.2, 'CV_bumunu': 0.2 # increasing the b->ulnu amplitude by 20%, while in the example the manual in page 7 you wrote Wilson ({ ’ CVRR_bdbd ’: 1 e - 10 , ’ CVRR_bsbs ’: 1 e - 10} , scale =160 , eft = ’ WET ’ , basis = ’ flavio ’). What is the difference between the WC values in these two examples? To me, it looks like in the first example the WC values represent the ratio between the np and sm WC. While in the second example it looks like that the wc value is the absolute np wc value. Is that right?

Ahmed Rashed

[DavidMStraub]

This is how the WCs are defined:
https://wcxf.github.io/assets/pdf/WET.flavio.pdf

[amrashed]

Is there any way to access the values of the wc_sm of the observables, such as B+->K*mumu?

[DavidMStraub]

This is not easily accessible, and it is intentional as they are not as easy to define as the NP contributions. There are many subtleties as the SM WCs are really only well defined together with the matrix elements, and changing one without the other (e.g. the scheme or scale) is inconsistent. This is also why the SM WCs can't be easily changed.