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0795afa3 | 1 | #include "isajet/pilot.h" |
2 | SUBROUTINE SSHGM1(TAU,IFFF,RFFF) | |
3 | C----------------------------------------------------------------------- | |
4 | C | |
5 | C This subroutine uses the tau variable of the Higgs Hunters' | |
6 | C Guide. Many other authors, including the paper cited in | |
7 | C Higgs Hunters' Guide (PR. D. 38(11): 3481) and Collider Physics | |
8 | C by Barger and Phillips use the variable lambda | |
9 | C LAMBDA = ( MASS OF PARTICLE IN LOOP / MASS OF HIGGS )**2 | |
10 | C TAU = 4.0 * LAMBDA | |
11 | C Note also that what is defined as the f function by different | |
12 | C authors varies by a constant factor. For example, | |
13 | C f(Barger and Phillips) = -2 * f(Higgs Hunters' Guide) | |
14 | C | |
15 | C Bisset's FFF | |
16 | C----------------------------------------------------------------------- | |
17 | #if defined(CERNLIB_IMPNONE) | |
18 | IMPLICIT NONE | |
19 | #endif | |
20 | DOUBLE PRECISION TAU,IFFF,RFFF,ETAP,ETAM,PI | |
21 | C | |
22 | PI=3.1415926536 | |
23 | IFFF=0.0 | |
24 | RFFF=0.0 | |
25 | IF(TAU.GE.1.0) THEN | |
26 | RFFF=(DASIN(DSQRT(1.0/TAU)))**2 | |
27 | IFFF=0.0D0 | |
28 | ELSE IF (TAU.LT.1.0) THEN | |
29 | ETAP=1.0D0+SQRT(1.0D0-TAU) | |
30 | ETAM=1.0D0-SQRT(1.0D0-TAU) | |
31 | RFFF=-((DLOG(ETAP/ETAM))**2-PI**2)/4.0D0 | |
32 | IFFF=PI*DLOG(ETAP/ETAM)/2.0D0 | |
33 | ENDIF | |
34 | RETURN | |
35 | END |