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fe4da5cc | 1 | * |
2 | * $Id$ | |
3 | * | |
4 | * $Log$ | |
5 | * Revision 1.1.1.1 1995/10/24 10:19:58 cernlib | |
6 | * Geant | |
7 | * | |
8 | * | |
9 | #include "geant321/pilot.h" | |
10 | *CMZ : 3.21/02 29/03/94 15.41.44 by S.Giani | |
11 | *-- Author : | |
12 | *$ CREATE TWOPAR.FOR | |
13 | *COPY TWOPAR | |
14 | * | |
15 | *=== twopar ===========================================================* | |
16 | * | |
17 | SUBROUTINE TWOPAR(E1,E2,P1,P2,COD1,COD2,COF1,COF2,SIF1,SIF2, | |
18 | 1IT1,IT2,UMOO,ECM,P,N,AM1,AM2) | |
19 | ||
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 | |
27 | C IN THE CM - SYSTEM | |
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) | |
34 | 9 CONTINUE | |
35 | AMA=AM1 | |
36 | AMB=AM2 | |
37 | AMA2=AMA*AMA | |
38 | AMB2=AMB*AMB | |
39 | S=UMOO*UMOO | |
40 | E1=(S-AMB2+AMA2)/(2.D0*UMOO) | |
41 | E2=(S-AMA2+AMB2)/(2.D0*UMOO) | |
42 | AMTE=MAX(E1*E1-AMA2,ZERZER) | |
43 | 11 CONTINUE | |
44 | AMTE=AMTE | |
45 | P1=SQRT(AMTE) | |
46 | P2=P1 | |
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 ) | |
53 | CALL COSI(COF1,SIF1) | |
54 | COF2=-COF1 | |
55 | SIF2=-SIF1 | |
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) | |
60 | COD2=-COD1 | |
61 | RETURN | |
62 | END |