5 * Revision 1.1.1.1 1995/10/24 10:19:58 cernlib
9 #include "geant321/pilot.h"
10 *CMZ : 3.21/02 29/03/94 15.41.44 by S.Giani
15 *=== twopar ===========================================================*
17 SUBROUTINE TWOPAR(E1,E2,P1,P2,COD1,COD2,COF1,COF2,SIF1,SIF2,
18 1IT1,IT2,UMOO,ECM,P,N,AM1,AM2)
20 #include "geant321/dblprc.inc"
21 #include "geant321/dimpar.inc"
22 #include "geant321/iounit.inc"
23 C ******************************************************
24 C QUASI TWO PARTICLE PRODUCTION
25 C TWOPAR CALCULATES THE ENERGYS AND THE MOMENTA
26 C FOR THE CREATED PARTICLES OR RESONANCES IT1 AND IT2
28 C COD1,COD2,COF1,COF2,SIF1,SIF2 ARE THE ANGLES FOR
29 C SPHERICAL COORDINATES
30 C ******************************************************
31 COMMON /FKGAMR/ REDU,AMO,AMM(15 )
32 COMMON/FKABLT/AM(110),GA(110),TAU(110),ICH(110)
33 *,IBAR(110),K1(110),K2(110)
40 E1=(S-AMB2+AMA2)/(2.D0*UMOO)
41 E2=(S-AMA2+AMB2)/(2.D0*UMOO)
42 AMTE=MAX(E1*E1-AMA2,ZERZER)
47 C / P2 / = / P1 / BUT OPPOSITE DIRECTIONS
48 C DETERMINATION OF THE ANGLES
49 C COS(THETA1)=COD1 COS(THETA2)=COD2
50 C SIN(PHI1)=SIF1 SIN(PHI2)=SIF2
51 C COS(PHI1)=COF1 COS(PHI2)=COF2
52 C PHI IS UNIFORMLY DISTRIBUTED IN ( 0,2*PI )
56 C CALCULATION OF THETA1
57 CALL TCHOIC(TR,P,P1,ECM,E1,IT1,IT2,N,AM1,AM2)
58 COD1=(TR-AMA2-AM(N)*AM(N)+2.D0*ECM*E1)/(2.D0*P*P1+1.D-18)
59 IF (ABS(COD1) .GT. 1.D+00) COD1 = SIGN (ONEONE,COD1)