Simultaneous Fits and sPlot

Hi guys,

I am trying to perform a simultaneous fit to two independent sWeighted data sets in order to extract a shared parameter, but I am finding that the fit does not produce accurate results for the value of the parameter (which I know as I use its true value in order to generate the data). I was wondering if perhaps the simultaneous fit method does not properly account for the weights produced by sPlot or whether something else might be going on?

Any ideas would be much appreciated!

Thanks in advance.


The fit should work, also for weighted events. In case of weights you need to use a special procedure to get the right error, but this should not affect the central value.
It could be that the fit does not converge correctly.
If you can please post your code and the data needed to reproduce your fit

Best Regards


Hi Lorenzo,

Thank you for your reply. I have now fixed the problem and have the fit working properly. Regarding the special procedure you mentioned for the errors, how does this work?

Thank you.

Kind regards,


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