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Commit | Line | Data |
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fe4da5cc | 1 | |
2 | C********************************************************************* | |
3 | ||
4 | FUNCTION PYHFTH(SH,SQM,FRATT) | |
5 | ||
6 | C...Gives threshold attractive/repulsive factor for heavy flavour | |
7 | C...production. | |
8 | COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200) | |
9 | COMMON/PYPARS/MSTP(200),PARP(200),MSTI(200),PARI(200) | |
10 | COMMON/PYINT1/MINT(400),VINT(400) | |
11 | SAVE /LUDAT1/ | |
12 | SAVE /PYPARS/,/PYINT1/ | |
13 | ||
14 | C...Value for alpha_strong. | |
15 | IF(MSTP(35).LE.1) THEN | |
16 | ALSSG=PARP(35) | |
17 | ELSE | |
18 | MST115=MSTU(115) | |
19 | MSTU(115)=MSTP(36) | |
20 | Q2BN=SQRT(MAX(1.,SQM*((SQRT(SH)-2.*SQRT(SQM))**2+PARP(36)**2))) | |
21 | ALSSG=ULALPS(Q2BN) | |
22 | MSTU(115)=MST115 | |
23 | ENDIF | |
24 | ||
25 | C...Evaluate attractive and repulsive factors. | |
26 | XATTR=4.*PARU(1)*ALSSG/(3.*SQRT(MAX(1E-20,1.-4.*SQM/SH))) | |
27 | FATTR=XATTR/(1.-EXP(-MIN(50.,XATTR))) | |
28 | XREPU=PARU(1)*ALSSG/(6.*SQRT(MAX(1E-20,1.-4.*SQM/SH))) | |
29 | FREPU=XREPU/(EXP(MIN(50.,XREPU))-1.) | |
30 | PYHFTH=FRATT*FATTR+(1.-FRATT)*FREPU | |
31 | VINT(138)=PYHFTH | |
32 | ||
33 | RETURN | |
34 | END |