hijing/src/lufowo.f

0001
0002 C*********************************************************************
0003
0004       SUBROUTINE LUFOWO(H10,H20,H30,H40)
0005
0006 C...Purpose: to calculate the first few Fox-Wolfram moments.
0007       COMMON/LUJETS/N,K(9000,5),P(9000,5),V(9000,5)
0008       SAVE /LUJETS/
0009       COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200)
0010       SAVE /LUDAT1/
0011       COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4)
0012       SAVE /LUDAT2/
0013
0014 C...Copy momenta for particles and calculate H0.
0015       NP=0
0016       H0=0.
0017       HD=0.
0018       DO 110 I=1,N
0019       IF(K(I,1).LE.0.OR.K(I,1).GT.10) GOTO 110
0020       IF(MSTU(41).GE.2) THEN
0021         KC=LUCOMP(K(I,2))
0022         IF(KC.EQ.0.OR.KC.EQ.12.OR.KC.EQ.14.OR.KC.EQ.16.OR.
0023      &  KC.EQ.18) GOTO 110
0024         IF(MSTU(41).GE.3.AND.KCHG(KC,2).EQ.0.AND.LUCHGE(K(I,2)).EQ.0)
0025      &  GOTO 110
0026       ENDIF
0027       IF(N+NP.GE.MSTU(4)-MSTU(32)-5) THEN
0028         CALL LUERRM(11,'(LUFOWO:) no more memory left in LUJETS')
0029         H10=-1.
0030         H20=-1.
0031         H30=-1.
0032         H40=-1.
0033         RETURN
0034       ENDIF
0035       NP=NP+1
0036       DO 100 J=1,3
0037   100 P(N+NP,J)=P(I,J)
0038       P(N+NP,4)=SQRT(P(I,1)**2+P(I,2)**2+P(I,3)**2)
0039       H0=H0+P(N+NP,4)
0040       HD=HD+P(N+NP,4)**2
0041   110 CONTINUE
0042       H0=H0**2
0043
0044 C...Very low multiplicities (0 or 1) not considered.
0045       IF(NP.LE.1) THEN
0046         CALL LUERRM(8,'(LUFOWO:) too few particles for analysis')
0047         H10=-1.
0048         H20=-1.
0049         H30=-1.
0050         H40=-1.
0051         RETURN
0052       ENDIF
0053
0054 C...Calculate H1 - H4.
0055       H10=0.
0056       H20=0.
0057       H30=0.
0058       H40=0.
0059       DO 120 I1=N+1,N+NP
0060       DO 120 I2=I1+1,N+NP
0061       CTHE=(P(I1,1)*P(I2,1)+P(I1,2)*P(I2,2)+P(I1,3)*P(I2,3))/
0062      &(P(I1,4)*P(I2,4))
0063       H10=H10+P(I1,4)*P(I2,4)*CTHE
0064       H20=H20+P(I1,4)*P(I2,4)*(1.5*CTHE**2-0.5)
0065       H30=H30+P(I1,4)*P(I2,4)*(2.5*CTHE**3-1.5*CTHE)
0066       H40=H40+P(I1,4)*P(I2,4)*(4.375*CTHE**4-3.75*CTHE**2+0.375)
0067   120 CONTINUE
0068
0069 C...Calculate H1/H0 - H4/H0. Output.
0070       MSTU(61)=N+1
0071       MSTU(62)=NP
0072       H10=(HD+2.*H10)/H0
0073       H20=(HD+2.*H20)/H0
0074       H30=(HD+2.*H30)/H0
0075       H40=(HD+2.*H40)/H0
0076
0077       RETURN
0078       END