* * $Id$ * * $Log$ * Revision 1.1 2000/06/19 20:00:31 eugenio * Initial revision * * Revision 1.1.1.1 1994/11/22 16:57:03 zfiles * first version of korb in CVS * * #include "sys/CLEO_machine.h" #include "pilot.h" *CMZ : 2.00/00 21/01/93 15.42.34 by Alan Weinstein *-- Author : SUBROUTINE $ DPHTRE(DGAMT,HV,PN,PAA,PIM1,AMPA,PIM2,AMPB,PIPL,AMP3,KEYT,MNUM) C ---------------------------------------------------------------------- * IT SIMULATES A1 DECAY IN TAU REST FRAME WITH * Z-AXIS ALONG A1 MOMENTUM * it can be also used to generate K K pi and K pi pi tau decays. * INPUT PARAMETERS * KEYT - algorithm controlling switch * 2 - flat phase space PIM1 PIM2 symmetrized statistical factor 1/2 * 1 - like 1 but peaked around a1 and rho (two channels) masses. * 3 - peaked around omega, all particles different * other- flat phase space, all particles different * AMP1 - mass of first pi, etc. (1-3) * MNUM - matrix element type * 0 - a1 matrix element * 1-6 - matrix element for K pi pi, K K pi decay modes * 7 - pi- pi0 gamma matrix element C ---------------------------------------------------------------------- COMMON / PARMAS / AMTAU,AMNUTA,AMEL,AMNUE,AMMU,AMNUMU * ,AMPIZ,AMPI,AMRO,GAMRO,AMA1,GAMA1 * ,AMK,AMKZ,AMKST,GAMKST C REAL*4 AMTAU,AMNUTA,AMEL,AMNUE,AMMU,AMNUMU * ,AMPIZ,AMPI,AMRO,GAMRO,AMA1,GAMA1 * ,AMK,AMKZ,AMKST,GAMKST COMMON / DECPAR / GFERMI,GV,GA,CCABIB,SCABIB,GAMEL REAL*4 GFERMI,GV,GA,CCABIB,SCABIB,GAMEL REAL HV(4),PT(4),PN(4),PAA(4),PIM1(4),PIM2(4),PIPL(4) REAL PR(4) REAL*4 RRR(5) DATA PI /3.141592653589793238462643/ DATA ICONT /0/ XLAM(X,Y,Z)=SQRT(ABS((X-Y-Z)**2-4.0*Y*Z)) C AMRO, GAMRO IS ONLY A PARAMETER FOR GETING HIGHT EFFICIENCY C C THREE BODY PHASE SPACE NORMALISED AS IN BJORKEN-DRELL C D**3 P /2E/(2PI)**3 (2PI)**4 DELTA4(SUM P) PHSPAC=1./2**17/PI**8 C TAU MOMENTUM PT(1)=0. PT(2)=0. PT(3)=0. PT(4)=AMTAU C CALL RANMAR(RRR,5) RR=RRR(5) C CALL CHOICE(MNUM,RR,ICHAN,PROB1,PROB2,PROB3, $ AMRX,GAMRX,AMRA,GAMRA,AMRB,GAMRB) IF (ICHAN.EQ.1) THEN AMP1=AMPB AMP2=AMPA ELSEIF (ICHAN.EQ.2) THEN AMP1=AMPA AMP2=AMPB ELSE AMP1=AMPB AMP2=AMPA ENDIF CAM RR1=RRR(1) AMS1=(AMP1+AMP2+AMP3)**2 AMS2=(AMTAU-AMNUTA)**2 * PHASE SPACE WITH SAMPLING FOR A1 RESONANCE ALP1=ATAN((AMS1-AMRX**2)/AMRX/GAMRX) ALP2=ATAN((AMS2-AMRX**2)/AMRX/GAMRX) ALP=ALP1+RR1*(ALP2-ALP1) AM3SQ =AMRX**2+AMRX*GAMRX*TAN(ALP) AM3 =SQRT(AM3SQ) PHSPAC=PHSPAC*((AM3SQ-AMRX**2)**2+(AMRX*GAMRX)**2)/(AMRX*GAMRX) PHSPAC=PHSPAC*(ALP2-ALP1) C MASS OF (REAL/VIRTUAL) RHO - RR2=RRR(2) AMS1=(AMP2+AMP3)**2 AMS2=(AM3-AMP1)**2 IF (ICHAN.LE.2) THEN * PHASE SPACE WITH SAMPLING FOR RHO RESONANCE, ALP1=ATAN((AMS1-AMRA**2)/AMRA/GAMRA) ALP2=ATAN((AMS2-AMRA**2)/AMRA/GAMRA) ALP=ALP1+RR2*(ALP2-ALP1) AM2SQ =AMRA**2+AMRA*GAMRA*TAN(ALP) AM2 =SQRT(AM2SQ) C --- THIS PART OF THE JACOBIAN WILL BE RECOVERED LATER --------------- C PHSPAC=PHSPAC*(ALP2-ALP1) C PHSPAC=PHSPAC*((AM2SQ-AMRA**2)**2+(AMRA*GAMRA)**2)/(AMRA*GAMRA) C---------------------------------------------------------------------- ELSE * FLAT PHASE SPACE; AM2SQ=AMS1+ RR2*(AMS2-AMS1) AM2 =SQRT(AM2SQ) PHF0=(AMS2-AMS1) ENDIF * RHO RESTFRAME, DEFINE PIPL AND PIM1 ENQ1=(AM2SQ-AMP2**2+AMP3**2)/(2*AM2) ENQ2=(AM2SQ+AMP2**2-AMP3**2)/(2*AM2) PPI= ENQ1**2-AMP3**2 PPPI=SQRT(ABS(ENQ1**2-AMP3**2)) C --- this part of jacobian will be recovered later PHF1=(4*PI)*(2*PPPI/AM2) * PI MINUS MOMENTUM IN RHO REST FRAME CALL SPHERA(PPPI,PIPL) PIPL(4)=ENQ1 * PI0 1 MOMENTUM IN RHO REST FRAME DO 30 I=1,3 30 PIM1(I)=-PIPL(I) PIM1(4)=ENQ2 * A1 REST FRAME, DEFINE PIM2 * RHO MOMENTUM PR(1)=0 PR(2)=0 PR(4)=1./(2*AM3)*(AM3**2+AM2**2-AMP1**2) PR(3)= SQRT(ABS(PR(4)**2-AM2**2)) PPI = PR(4)**2-AM2**2 * PI0 2 MOMENTUM PIM2(1)=0 PIM2(2)=0 PIM2(4)=1./(2*AM3)*(AM3**2-AM2**2+AMP1**2) PIM2(3)=-PR(3) PHF2=(4*PI)*(2*PR(3)/AM3) * OLD PIONS BOOSTED FROM RHO REST FRAME TO A1 REST FRAME EXE=(PR(4)+PR(3))/AM2 CALL BOSTR3(EXE,PIPL,PIPL) CALL BOSTR3(EXE,PIM1,PIM1) RR3=RRR(3) RR4=RRR(4) CAM THET =PI*RR3 THET =ACOS(-1.+2*RR3) PHI = 2*PI*RR4 CALL ROTPOL(THET,PHI,PIPL) CALL ROTPOL(THET,PHI,PIM1) CALL ROTPOL(THET,PHI,PIM2) CALL ROTPOL(THET,PHI,PR) C * NOW TO THE TAU REST FRAME, DEFINE A1 AND NEUTRINO MOMENTA * A1 MOMENTUM PAA(1)=0 PAA(2)=0 PAA(4)=1./(2*AMTAU)*(AMTAU**2-AMNUTA**2+AM3**2) PAA(3)= SQRT(ABS(PAA(4)**2-AM3**2)) PPI = PAA(4)**2-AM3**2 PHSPAC=PHSPAC*(4*PI)*(2*PAA(3)/AMTAU) * TAU-NEUTRINO MOMENTUM PN(1)=0 PN(2)=0 PN(4)=1./(2*AMTAU)*(AMTAU**2+AMNUTA**2-AM3**2) PN(3)=-PAA(3) C HERE WE CORRECT FOR THE JACOBIANS OF THE TWO CHAINS C ---FIRST CHANNEL ------- PIM1+PIPL AMS1=(AMP2+AMP3)**2 AMS2=(AM3-AMP1)**2 ALP1=ATAN((AMS1-AMRA**2)/AMRA/GAMRA) ALP2=ATAN((AMS2-AMRA**2)/AMRA/GAMRA) XPRO = (PIM1(3)+PIPL(3))**2 $ +(PIM1(2)+PIPL(2))**2+(PIM1(1)+PIPL(1))**2 AM2SQ=-XPRO+(PIM1(4)+PIPL(4))**2 C JACOBIAN OF SPEEDING FF1 = ((AM2SQ-AMRA**2)**2+(AMRA*GAMRA)**2)/(AMRA*GAMRA) FF1 =FF1 *(ALP2-ALP1) C LAMBDA OF RHO DECAY GG1 = (4*PI)*(XLAM(AM2SQ,AMP2**2,AMP3**2)/AM2SQ) C LAMBDA OF A1 DECAY GG1 =GG1 *(4*PI)*SQRT(4*XPRO/AM3SQ) XJAJE=GG1*(AMS2-AMS1) C ---SECOND CHANNEL ------ PIM2+PIPL AMS1=(AMP1+AMP3)**2 AMS2=(AM3-AMP2)**2 ALP1=ATAN((AMS1-AMRB**2)/AMRB/GAMRB) ALP2=ATAN((AMS2-AMRB**2)/AMRB/GAMRB) XPRO = (PIM2(3)+PIPL(3))**2 $ +(PIM2(2)+PIPL(2))**2+(PIM2(1)+PIPL(1))**2 AM2SQ=-XPRO+(PIM2(4)+PIPL(4))**2 FF2 = ((AM2SQ-AMRB**2)**2+(AMRB*GAMRB)**2)/(AMRB*GAMRB) FF2 =FF2 *(ALP2-ALP1) GG2 = (4*PI)*(XLAM(AM2SQ,AMP1**2,AMP3**2)/AM2SQ) GG2 =GG2 *(4*PI)*SQRT(4*XPRO/AM3SQ) XJADW=GG2*(AMS2-AMS1) C A1=0.0 A2=0.0 A3=0.0 XJAC1=FF1*GG1 XJAC2=FF2*GG2 IF (ICHAN.EQ.2) THEN XJAC3=XJADW ELSE XJAC3=XJAJE ENDIF IF (XJAC1.NE.0.0) A1=PROB1/XJAC1 IF (XJAC2.NE.0.0) A2=PROB2/XJAC2 IF (XJAC3.NE.0.0) A3=PROB3/XJAC3 C IF (A1+A2+A3.NE.0.0) THEN PHSPAC=PHSPAC/(A1+A2+A3) ELSE PHSPAC=0.0 ENDIF IF(ICHAN.EQ.2) THEN DO 70 I=1,4 X=PIM1(I) PIM1(I)=PIM2(I) 70 PIM2(I)=X ENDIF * ALL PIONS BOOSTED FROM A1 REST FRAME TO TAU REST FRAME * Z-AXIS ANTIPARALLEL TO NEUTRINO MOMENTUM EXE=(PAA(4)+PAA(3))/AM3 CALL BOSTR3(EXE,PIPL,PIPL) CALL BOSTR3(EXE,PIM1,PIM1) CALL BOSTR3(EXE,PIM2,PIM2) CALL BOSTR3(EXE,PR,PR) C PARTIAL WIDTH CONSISTS OF PHASE SPACE AND AMPLITUDE IF (MNUM.EQ.8) THEN CALL DAMPOG(PT,PN,PIM1,PIM2,PIPL,AMPLIT,HV) C ELSEIF (MNUM.EQ.0) THEN C CALL DAMPAA(PT,PN,PIM1,PIM2,PIPL,AMPLIT,HV) ELSE CALL DAMPPK(MNUM,PT,PN,PIM1,PIM2,PIPL,AMPLIT,HV) ENDIF IF (KEYT.EQ.1.OR.KEYT.EQ.2) THEN C THE STATISTICAL FACTOR FOR IDENTICAL PI'S IS CANCELLED WITH C TWO, FOR TWO MODES OF A1 DECAY NAMELLY PI+PI-PI- AND PI-PI0PI0 PHSPAC=PHSPAC*2.0 PHSPAC=PHSPAC/2. ENDIF DGAMT=1/(2.*AMTAU)*AMPLIT*PHSPAC END