BOSS_7.0.2: /home/bes3soft/bes3soft/Boss/7.0.2/dist/7.0.2/Generator/BesEvtGen/BesEvtGen-00-03-58/user/LcLc2.C Source File

00001 //---- read out the momentum for each particle, then using them to calculate the amplitude squared, for example:
00002 /*********** using the following decay cards ****************
00003 where spin for Lambda_c and anti-Lambda_c is assumed to be 3/2 for spin-test
00004 Particle vpho 4.6 0
00005 
00006 Decay vpho
00007 1 Lambda_c+ anti-Lambda_c- PHSP;
00008 Enddecay
00009 
00010 Decay Lambda_c+
00011 1 Lambda0 pi+  PHSP;
00012 Enddecay
00013 
00014 Decay anti-Lambda_c-
00015 1 anti-Lambda0 pi-  PHSP;
00016 Enddecay
00017 
00018 Decay Lambda0
00019 1 p+ pi- PHSP;
00020 Enddecay
00021 
00022 Decay anti-Lambda0
00023 1 anti-p- pi+ PHSP;
00024 Enddecay
00025 
00026 End
00027 */
00028 //----------------------------------
00029   EvtVector4R vpho,lambdac,lambdacbar,lambda,lambdabar,proton,antiproton;
00030   vpho      = part->getP4();              //vpho momentum  
00031   lambdac   = part->getDaug(0)->getP4();  //lambda_c+ momentum 
00032   lambdacbar= part->getDaug(1)->getP4();  //anti-Lambda_c-  momentum
00033   lambda    = part->getDaug(0)->getDaug(0)->getP4();  //Lambda momentum
00034   lambdabar = part->getDaug(1)->getDaug(0)->getP4();  //anti-Lambda momentum
00035 
00036   EvtHelSys angles0(vpho,lambdac);
00037   double theta0 = angles0.getHelAng(1);
00038   double phi0   = angles0.getHelAng(2);
00039  
00040   EvtHelSys angles1(lambdac,lambda);
00041   double theta1 = angles1.getHelAng(1);
00042   double phi1   = angles1.getHelAng(2);
00043 
00044   EvtHelSys angles2(lambdacbar,lambdabar);
00045   double theta2 = angles2.getHelAng(1);
00046   double phi2   = angles2.getHelAng(2);
00047   
00048   amps = myamps_(&theta0,&theta1,&theta2);