Error in observable for Eta LFV decays

[Joro20]

Hello,

I was trying to estimate some LFV decays from eta/eta^{\prime} meson and was using the code available in the Flavio, but it seems complaining about the observable itself! The MWE is below:

import numpy as np
print('loading wilson and flavio')
from wilson import Wilson
import flavio
`print('done\n')

import random
for i in np.arange(1,50,0.5):,
random2=random.uniform(-2.5,-2.3),
ref_WC2=10**(-random2),
ref_scale = 1e3  #in GeV units,
WC2 = 'lq3_1223' ,
wc2  = Wilson({WC2: ref_WC2/ref_scale/ref_scale}, scale=ref_scale, eft='SMEFT', basis='Warsaw'),
BR_Etab1Smue=flavio.np_prediction('BR(eta_b(1S)->mue)',wc2),
print(ref_WC2,BR_Etab1Smue)
``` `


But the error message is

Keyerror:'BR(eta_b(1S)->mue)'

I'm not sure what is wrong! Please help.

[DavidMStraub]

Please check the docs for observables that exist: https://flav-io.github.io/docs/observables.html

[Joro20]

It is indeed a listed listed observable under the quarkonium lepton decays! Please see the attachment.

[peterstangl]

I'm not able to reproduce the error you see using the latest flavio version.

Which version of flavio are you using? You can check e.g. using print(flavio.__version__). The LFV quarkonium decays have been added in version 2.5.0 (see https://github.com/flav-io/flavio/releases/tag/v2.5.0). If you use an older version of flavio, these observables are not available.

[DavidMStraub]

@peterstangl could this be due to PyRunDec not having Python 3.13 wheels yet?

[peterstangl]

@DavidMStraub, yes it seems the problem is the missing rundec wheels for Python 3.13. I have opened PR DavidMStraub/rundec-python#16 to fix this.

[Joro20]

Should I then wait for the problem to be fixed ?

[peterstangl]

Should I then wait for the problem to be fixed ?

Everything should work on Python 3.6 - 3.12. So if you don't want to wait you can use any of those Python versions. If you want to use Python 3.13, you will have to wait until rundec-python (one of the dependencies of wilson) supports Python 3.13 (which was just released two weeks ago).

[Joro20]

Thank you for explaining the reason. I've been able to use Flavio with Python version 3.12 and now my main issue is also solved.