[u/mrichter/AliRoot.git] / TEvtGen / PHOTOS / phocha.F

      FUNCTION PHOCHA(IDHEP)
C.----------------------------------------------------------------------
C.
C.    PHOTOS:   PHOton radiation in decays CHArge determination
C.
C.    Purpose:  Calculate the charge  of particle  with code IDHEP.  The
C.              code  of the  particle  is  defined by the Particle Data
C.              Group in Phys. Lett. B204 (1988) 1.
C.
C.    Input Parameter:   IDHEP
C.
C.    Output Parameter:  Funtion value = charge  of  particle  with code
C.                       IDHEP
C.
C.    Author(s):  E. Barberio and B. van Eijk     Created at:  29/11/89
C.                                                Last update: 02/01/90
C.
C.----------------------------------------------------------------------
      IMPLICIT NONE
      REAL*8 PHOCHA
      INTEGER IDHEP,IDABS,Q1,Q2,Q3
C--
C--   Array 'CHARGE' contains the charge  of the first 101 particles ac-
C--   cording  to  the PDG particle code... (0 is added for convenience)
      REAL*8 CHARGE(0:100)
      DATA CHARGE/ 0.D0,
     &-0.3333333333D0,  0.6666666667D0, -0.3333333333D0, 0.6666666667D0,
     &-0.3333333333D0,  0.6666666667D0, -0.3333333333D0, 0.6666666667D0,
     & 2*0.D0, -1.D0, 0.D0, -1.D0, 0.D0, -1.D0, 0.D0, -1.D0, 6*0.D0, 
     & 1.D0, 12*0.D0, 1.D0, 63*0.D0/
      IDABS=ABS(IDHEP)
      IF (IDABS.LE.100) THEN
C--
C--   Charge of quark, lepton, boson etc....
        PHOCHA = CHARGE(IDABS)
      ELSE
C--
C--   Check on particle build out of quarks, unpack its code...
        Q3=MOD(IDABS/1000,10)
        Q2=MOD(IDABS/100,10)
        Q1=MOD(IDABS/10,10)
        IF (Q3.EQ.0) THEN
C--
C--   ...meson...
          IF(MOD(Q2,2).EQ.0) THEN
            PHOCHA=CHARGE(Q2)-CHARGE(Q1)
          ELSE
            PHOCHA=CHARGE(Q1)-CHARGE(Q2)
          ENDIF
        ELSE
C--
C--   ...diquarks or baryon.
          PHOCHA=CHARGE(Q1)+CHARGE(Q2)+CHARGE(Q3)
        ENDIF
      ENDIF
C--
C--   Find the sign of the charge...
      IF (IDHEP.LT.0.D0) PHOCHA=-PHOCHA
      IF (PHOCHA**2.lt.1d-6) PHOCHA=0.D0
      RETURN
      END
Commit	Line	Data
da0e9ce3	1	FUNCTION PHOCHA(IDHEP)
	2	C.----------------------------------------------------------------------
	3	C.
	4	C. PHOTOS: PHOton radiation in decays CHArge determination
	5	C.
	6	C. Purpose: Calculate the charge of particle with code IDHEP. The
	7	C. code of the particle is defined by the Particle Data
	8	C. Group in Phys. Lett. B204 (1988) 1.
	9	C.
	10	C. Input Parameter: IDHEP
	11	C.
	12	C. Output Parameter: Funtion value = charge of particle with code
	13	C. IDHEP
	14	C.
	15	C. Author(s): E. Barberio and B. van Eijk Created at: 29/11/89
	16	C. Last update: 02/01/90
	17	C.
	18	C.----------------------------------------------------------------------
	19	IMPLICIT NONE
	20	REAL*8 PHOCHA
	21	INTEGER IDHEP,IDABS,Q1,Q2,Q3
	22	C--
	23	C-- Array 'CHARGE' contains the charge of the first 101 particles ac-
	24	C-- cording to the PDG particle code... (0 is added for convenience)
	25	REAL*8 CHARGE(0:100)
	26	DATA CHARGE/ 0.D0,
	27	&-0.3333333333D0, 0.6666666667D0, -0.3333333333D0, 0.6666666667D0,
	28	&-0.3333333333D0, 0.6666666667D0, -0.3333333333D0, 0.6666666667D0,
	29	& 20.D0, -1.D0, 0.D0, -1.D0, 0.D0, -1.D0, 0.D0, -1.D0, 60.D0,
	30	& 1.D0, 120.D0, 1.D0, 630.D0/
	31	IDABS=ABS(IDHEP)
	32	IF (IDABS.LE.100) THEN
	33	C--
	34	C-- Charge of quark, lepton, boson etc....
	35	PHOCHA = CHARGE(IDABS)
	36	ELSE
	37	C--
	38	C-- Check on particle build out of quarks, unpack its code...
	39	Q3=MOD(IDABS/1000,10)
	40	Q2=MOD(IDABS/100,10)
	41	Q1=MOD(IDABS/10,10)
	42	IF (Q3.EQ.0) THEN
	43	C--
	44	C-- ...meson...
	45	IF(MOD(Q2,2).EQ.0) THEN
	46	PHOCHA=CHARGE(Q2)-CHARGE(Q1)
	47	ELSE
	48	PHOCHA=CHARGE(Q1)-CHARGE(Q2)
	49	ENDIF
	50	ELSE
	51	C--
	52	C-- ...diquarks or baryon.
	53	PHOCHA=CHARGE(Q1)+CHARGE(Q2)+CHARGE(Q3)
	54	ENDIF
	55	ENDIF
	56	C--
	57	C-- Find the sign of the charge...
	58	IF (IDHEP.LT.0.D0) PHOCHA=-PHOCHA
	59	IF (PHOCHA**2.lt.1d-6) PHOCHA=0.D0
	60	RETURN
	61	END