void dalitzplot(TString input=""){
	
	
	gStyle->SetOptStat(0);

	TLorentzVector * plamFit = new TLorentzVector();
	TLorentzVector * pKFit = new TLorentzVector();
	TLorentzVector * pXiFit = new TLorentzVector();
	
	TLorentzVector * plamData = new TLorentzVector();
	TLorentzVector * pKData = new TLorentzVector();
	TLorentzVector * pXiData = new TLorentzVector();
	 
	TLorentzVector lamkFit, llamFit, lkFit, lXiFit, lXiKFit;
	TLorentzVector lamkData, llamData, lkData, lXiData, lXiKData;
	
	
	TFile * inFile = new TFile(input, "READ");
	
	
	TTree * fit = (TTree*) inFile->Get("_fittedFourvecs");
	fit->SetBranchAddress("Lambda", &plamFit);
	fit->SetBranchAddress("K-",&pKFit);
	fit->SetBranchAddress("Xibar+", &pXiFit);
	TLeaf * w = fit->GetLeaf("weight");
	
	TTree * Data = (TTree*) inFile->Get("_dataFourvecs");
	Data->SetBranchAddress("Lambda", &plamData);
	Data->SetBranchAddress("K-",&pKData);
	Data->SetBranchAddress("Xibar+", &pXiData);

	int nevts = fit->GetEntriesFast();

	TH2D * hFit = new TH2D("hFit","#bar{#Xi}^{+} #Lambda K^{-} Fit ", 50,2.5,3.2,50,3.2,4.1);
	TH2D * hData = new TH2D("hData","#bar{#Xi}^{+} #Lambda K^{-} Data ", 50,2.5,3.2,50,3.2,4.1);

	for (int i=0; i<nevts; i++){
		fit->GetEntry(i);
		Data->GetEntry(i);

		lkFit.SetXYZT(pKFit->X(), pKFit->Y(), pKFit->Z(), pKFit->E());
		llamFit.SetXYZT(plamFit->X(), plamFit->Y(), plamFit->Z(), plamFit->E());
		lXiFit.SetXYZT(pXiFit->X(), pXiFit->Y(), pXiFit->Z(), pXiFit->E());
		
		double weight=w->GetValue(0);
		
		lamkFit = lkFit + llamFit;
		lXiKFit = lkFit + lXiFit;
		
		
		hFit->Fill(lamkFit.M2(), lXiKFit.M2(), weight);
		
		lkData.SetXYZT(pKData->X(), pKData->Y(), pKData->Z(), pKData->E());
		llamData.SetXYZT(plamData->X(), plamData->Y(), plamData->Z(), plamData->E());
		lXiData.SetXYZT(pXiData->X(), pXiData->Y(), pXiData->Z(), pXiData->E());
		
		lamkData = lkData + llamData;
		lXiKData = lkData + lXiData;		
		
		hData->Fill(lamkData.M2(), lXiKData.M2(), weight);
		
	}
	
	TCanvas * c = new TCanvas("c", "", 0,0,1500,1000);
	c->Divide(2,1);
	
	c->cd(1);
	hData->GetZaxis()->SetRangeUser(0,60);
	hData->Draw("COLZ");
	c->cd(2);
	hFit->Draw("COLZ");

	c->Print("Dalitzplots.pdf");
	c->Print("Dalitzplots.png");
	c->Print("Dalitzplots.root");

	
}