hi all ROOTers,
consider the following problem:
- you have a signal (e.g. missing-mass-spektrum) which is
parameterized by a Lorentz convoluted with a Gaus.
the signal is on some kind of background wich you emulate by a
cubic function. after the fit i get as a result (let's say) seven
parameters.
NO PROBLEM SOFAR: see the famous FittingDemo and langaus tutorials.
now the problem:
i now split my data considering another observable (let's say ten
missing-mass distributions as a function of an angle of an ejectile).
i now have to fit ten INDIVIDUAL histos, however physics tells me
that the fits are correlated:
- the parameters should be 'some' smooth function of the additional observable.
- the probability of the fits should be 'some' smooth function of the additional observable.
- the sum of all signals should match the integral of the total signal.
now the question:
how can i simultaniously fit the ten histos? is there a ROOT-class?
are there some examples? one could think of some
multi-constraint, iterative fitting method; or one could try to
fit the surface of a TH2F filled with
h->Fill(missingmass, angle, totalcountsofthisbin).
i'm currently working on this problem, but the output is not yet what i'm aiming for.
thanx in advance,
martin
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