pd_delta_dalitz.C

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// p + d -> p + Delta0 -> p + n + p + pgamma* -> p + n + p + e- + e+
// This macro tests:
//   1. The deuteron Fermi sampling
//   2. The mass-dependent width Breit-Wigner distribution of the Delta 
//   3. The anisotropic (s+p wave) production angle for the pn->pDelta channel
//   4. The dilepton mass for Delta Dalitz decay
 
{
    gROOT->Reset();
 
    PParticle *p1 = new PParticle("p", 1.);          // projectile   = 1 GeV/u
    PParticle *p2 = new PParticle("d");             // target
    PParticle *p3 = new PParticle("p");
    PParticle *p4 = new PParticle("p");
    PParticle *delta = new PParticle("D0");
    
    PParticle *p5 = new PParticle("n");
    PParticle *dl = new PParticle("dilepton");
    
    PParticle *em = new PParticle("e-");
    PParticle *ep = new PParticle("e+");
    
    PParticle *q = new PParticle(*p1 + *p2);   // composite p+d
    
    PParticle *s1[4] = {q,p3,delta,p4};
    PParticle *s2[3] = {delta,p5,dl};
    PParticle *s3[3] = {dl,em,ep};
    
    PChannel *c1 = new PChannel(s1,3);
    PChannel *c2 = new PChannel(s2);
    PChannel *c3 = new PChannel(s3);
    PChannel *cc[] = {c1,c2,c3};
    
    PReaction *r = new PReaction(cc, "pd_delta_dalitz", 3, 1);
 
    r->Print();
    r->loop(100000);
    
    //data->Draw("M()","pid==34"); //Delta
 
}