A known spacing between two peaks, imposed as a Gaussian penalty. More...

Public Attributes
TString	channel
	Channel the two peaks belong to.
Int_t	peak_hi = 1
	Index of the upper peak.
Int_t	peak_lo = 0
	Index of the lower peak.
Double_t	delta = 0
	Known separation, in the observable's units.
Double_t	sigma = 0
	Uncertainty on delta; must be positive.

Detailed Description

A known spacing between two peaks, imposed as a Gaussian penalty.

Applies a penalty on mu_hi - mu_lo instead of fixing either centroid.

Note: Locking two centroids and constraining their separation are different statements. Locking pins the pair to an absolute energy scale as well; this leaves the pair free to slide together and forbids only the stretch between them.; sigma is the uncertainty on delta, which keeps the constraint a measurement rather than a hard equality. Set it to the literature error on the spacing.

Definition at line 243 of file RooFitUtils.hpp.