2 C*********************************************************************
6 C...Purpose: to give the mass of a particle/parton.
7 COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200)
8 COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4)
11 C...Reset variables. Compressed code.
20 C...Guarantee use of constituent masses for internal checks.
21 IF((MSTJ(93).EQ.1.OR.MSTJ(93).EQ.2).AND.KFA.LE.10) THEN
23 IF(MSTJ(93).EQ.2) ULMASS=MAX(0.,ULMASS-PARF(121))
25 C...Masses that can be read directly off table.
26 ELSEIF(KFA.LE.100.OR.KC.LE.80.OR.KC.GT.100) THEN
29 C...Find constituent partons and their masses.
35 KFLR=MOD(KFA/10000,10)
40 C...Construct masses for various meson, diquark and baryon cases.
41 IF(KFLA.EQ.0.AND.KFLR.EQ.0.AND.KFLS.LE.3) THEN
42 IF(KFLS.EQ.1) PMSPL=-3./(PMB*PMC)
43 IF(KFLS.GE.3) PMSPL=1./(PMB*PMC)
44 ULMASS=PARF(111)+PMB+PMC+PARF(113)*PARF(101)**2*PMSPL
45 ELSEIF(KFLA.EQ.0) THEN
50 ULMASS=PARF(113+KMUL)+PMB+PMC
51 ELSEIF(KFLC.EQ.0) THEN
52 IF(KFLS.EQ.1) PMSPL=-3./(PMA*PMB)
53 IF(KFLS.EQ.3) PMSPL=1./(PMA*PMB)
54 ULMASS=2.*PARF(112)/3.+PMA+PMB+PARF(114)*PARF(101)**2*PMSPL
55 IF(MSTJ(93).EQ.1) ULMASS=PMA+PMB
56 IF(MSTJ(93).EQ.2) ULMASS=MAX(0.,ULMASS-PARF(122)-
59 IF(KFLS.EQ.2.AND.KFLA.EQ.KFLB) THEN
60 PMSPL=1./(PMA*PMB)-2./(PMA*PMC)-2./(PMB*PMC)
61 ELSEIF(KFLS.EQ.2.AND.KFLB.GE.KFLC) THEN
62 PMSPL=-2./(PMA*PMB)-2./(PMA*PMC)+1./(PMB*PMC)
63 ELSEIF(KFLS.EQ.2) THEN
66 PMSPL=1./(PMA*PMB)+1./(PMA*PMC)+1./(PMB*PMC)
68 ULMASS=PARF(112)+PMA+PMB+PMC+PARF(114)*PARF(101)**2*PMSPL
72 C...Optional mass broadening according to truncated Breit-Wigner
73 C...(either in m or in m^2).
74 IF(MSTJ(24).GE.1.AND.PMAS(KC,2).GT.1E-4) THEN
75 IF(MSTJ(24).EQ.1.OR.(MSTJ(24).EQ.2.AND.KFA.GT.100)) THEN
76 ULMASS=ULMASS+0.5*PMAS(KC,2)*TAN((2.*RLU(0)-1.)*
77 & ATAN(2.*PMAS(KC,3)/PMAS(KC,2)))
80 PMLOW=ATAN((MAX(0.,PM0-PMAS(KC,3))**2-PM0**2)/
82 PMUPP=ATAN(((PM0+PMAS(KC,3))**2-PM0**2)/(PM0*PMAS(KC,2)))
83 ULMASS=SQRT(MAX(0.,PM0**2+PM0*PMAS(KC,2)*TAN(PMLOW+
84 & (PMUPP-PMLOW)*RLU(0))))