void reaction_LBL(void)
{
	TCanvas *c1 = new TCanvas("c1");
	c1->Range(-1.0, -1.0, +1.0, +1.0);
	
	gStyle->SetLineWidth(6);
	
	TCurlyLine *gamma1 = new TCurlyLine(-0.8, -0.0, -0.2, 0.0);
	gamma1->SetWavy();
	gamma1->SetWaveLength(0.08);
	AddEndArrowHead(gamma1);
	gamma1->Draw();

	TEllipse *proton = new TEllipse(-0.1, 0.0, 0.03, 0.03*7.0/5.0);
	proton->SetFillColor(kBlack);
	proton->Draw();
	
	TArrow *pip = new TArrow(-0.1, 0.0, 0.75, 0.75, 0.05, "->");
	pip->Draw();

	TArrow *pim = new TArrow(-0.1, 0.0, 0.75, +0.0, 0.05, "->");
	pim->Draw();

	TArrow *neutron = new TArrow(-0.1, 0.0, +0.75, -0.75, 0.05, "->");
	neutron->Draw();
	
	TLatex t;
	t.SetTextSize(0.2);

	t.DrawLatex(-0.95, -0.093, "#gamma");
	t.DrawLatex(0.761, -0.932, "#it{Z'}");
	t.DrawLatex(0.767, -0.089, "#pi^{-}");
	t.DrawLatex(0.767, 0.703, "#pi^{+}");
	t.DrawLatex(-0.207, -0.369, "#it{Z}");
	
	c1->SaveAs("reaction_LBL.png");
	c1->SaveAs("reaction_LBL.pdf");
}

void AddMiddleArrowHead(TCurlyLine *cl)
{
	double xmid = (cl->GetStartX() + cl->GetEndX())/2.0;
	double ymid = (cl->GetStartY() + cl->GetEndY())/2.0;
	double dX = (cl->GetEndX() - cl->GetStartX())/1000.0;
	double dY = (cl->GetEndY() - cl->GetStartY())/1000.0;
	
	xmid += 10.0*dX;
	ymid += 10.0*dY;

	TArrow *arrow = new TArrow(xmid, ymid, xmid+dX, ymid+dY, 0.05, "->-");
	arrow->Draw();
}

void AddEndArrowHead(TCurlyLine *cl)
{
	double xend = cl->GetEndX();
	double yend = cl->GetEndY();
	double dX = (cl->GetEndX() - cl->GetStartX())/1000.0;
	double dY = (cl->GetEndY() - cl->GetStartY())/1000.0;
		
	TArrow *arrow = new TArrow(xend-dX, yend-dY, xend, yend, 0.05, "->-");
	arrow->Draw();
}