Subroutine tnucth (jj1,jj2,kp,k,k0,cthnuc,tofth,mn) c *** see RH Landau, Program lpott, 1981 c tnucth calculates the theta dependent ampl in pi-nucleus frame c with angle dependent po Implicit Real*8 (a-h,i,k,m,o-z) Dimension nifty(20), bnuc(20), bnucf(20), bn(16), bnf(16), retij 1(14), imtij(14), tofth(8) Dimension km(4), qim(4), em(4), qm(2), pm(4), kapm(4), alph(4), 1 beta(4) Common /sec2/ bnuc,bn,bnucf,bnf,retij,imtij,hbarc,pi,mpi,xmn,nz, 1nes,nwaves,nifty,na c tofth(j) code, t = ...,for j=... c 1 retp-spinindep 2 imtp-spin indep c 3 retn- spin indep 4 imtn-spin indep c 5 retp-spin dependt 6 imtp-spin dep c 7 retn-soin dept 8 imtn spon-depend c statement functions now follow epi(p) = Sqrt(mpi2+p*p) en(p) = Sqrt(mn2+p*p) c the pi-nucleon c.o.m.. momemtum**2 for given s kcm2(s) = (s-(mpi+mn)**2)*(s-(mpi-mn)**2)/4./s c internal nucleon energy, new optimal definition eint(p,pp) = Sqrt(mn2+(rhl1**2)*p*p*0.25+(rhl2**2)*pp*pp*0.25-0.5* 1rhl1*rhl2*p*pp*cthnuc) c softh is the new,optimal,theta-dependent s softh(p,pp) = mpi2+mn2+rhl1*p*p-rhl2*p*pp*cthnuc+2.*epi(p)*eint(p, 1pp) nit = 1 amass = na*mn/xmn ma = na*xmn rhl1 = (amass+1.)/amass rhl2 = (amass-1.)/amass mn2 = mn*mn mpi2 = mpi*mpi m12 = (ma-mn)**2 rhl3 = mpi2-mn2 ma2 = ma*ma sin = softh(k,kp) sout = softh(kp,k) enin = eint(k,kp) enout = eint(kp,k) If ((nifty(5).gt.5).and.(nifty(5).ne.9)) GoTo 20 c calculate on-shell kappa with 2 body energy son = softh(k0,k0) kapon2 = kcm2(son) kapon = Sqrt(kapon2) kap2 = kcm2(sin) kap = Sqrt(kap2) kapp2 = kcm2(sout) kapp = Sqrt(kapp2) If (kapp.le.0.) kapp = 0.0001 If (kap.le.0.) kap = 0.0001 cthn = ((epi(kap)*epi(kapp)-epi(k)*epi(kp))/kapp/kap)+k*kp*cthnuc/ 1kap/kapp If (nifty(5).eq.2) cthn = cthnuc If (abs(cthn).le.2.) GoTo 10 Write (6,100) cthn 10 Continue gamth = Sqrt(epi(kap)*epi(kapp)*en(kap)*en(kapp)/(epi(k)*epi(kp)* 1enin*enout)) costh = cthn factor = gamth c choose defintion of energy c nifty(5)=0 % use softh(on shell k) c 1 use sin of theata (incoming momentum) c 9 use softh(on shell k)plus aay angles c 2 softh (on shell), no angle t.f. kape = kapon If (nifty(5).eq.1) kape = kap ekape = epi(kape)+en(kape) If (nifty(5).lt.5) GoTo 70 If (nifty(5).eq.9) GoTo 40 c 3 body def of energy c nifty(5)= 5: e3b with nonfolded or w0-folded t + old,optimal angle c =7: same as above yet with aay magic angle t.f.(standard) c n.b. n(5)=7 is the standard case, whereas 6 is for trial c Dont use 6 If have w0-folded t s 20 Continue spinuc = epi(k0)+Sqrt(ma2+k0*k0) q2 = kp*kp+k*k-2.*kp*k*cthnuc qk = k*kp*cthnuc-k*k be = 5.*nifty(2) pkap2 = rhl2*rhl2*(k*k+q2/4.+174.*174.+qk) ekape = spinuc-be-Sqrt(pkap2+m12) ekape = ekape*ekape-pkap2 c e3b-folded t s being used c non reltv def for folding If (nifty(5).ne.6) GoTo 30 twomu = 2.*(mpi+mn)*(ma-mn)/(mpi+ma) ekape = spinuc-ma+mn+5-be-(k*k+(q2-k0*k0)/4.+qk)*rhl2*rhl2/twomu 30 rhl = 1. If (ekape.lt.0.) rhl = -1. ekape = rhl*Sqrt(rhl*ekape) If (nifty(5).eq.5) GoTo 70 c nifty(5) = 6,7,9 use magic vector prescription(aay) c 1st two components x,y of kin, 3rd 4th,x y of kout 40 rhl = Sqrt(1.-cthnuc**2) ki0 = epi(k)+eint(k,kp) kf0 = epi(kp)+eint(kp,k) km(1) = k km(2) = 0. km(3) = kp*cthnuc km(4) = kp*rhl Do 50 j=1,2 j2 = j+2 qm(j) = km(j2)-km(j) pm(j) = -km(j)/amass+rhl2*qm(j)/2. pm(j2) = pm(j)-qm(j) kapm(j) = km(j)+pm(j) kapm(j2) = kapm(j) alph(j) = rhl3/sin alph(j2) = rhl3/sout qim(j) = 0.5*(km(j)-pm(j)-alph(j)*kapm(j)) qim(j2) = 0.5*(km(j2)-pm(j2)-alph(j2)*kapm(j2)) beta(j) = qim(j)*kapm(j)/ki0/(ki0+Sqrt(sin)) beta(j2) = qim(j2)*kapm(j2)/kf0/(kf0+Sqrt(sout)) If (j.ne.2) GoTo 50 beta(1) = beta(1)+beta(2) beta(2) = beta(1) beta(3) = beta(3)+beta(4) beta(4) = beta(3) 50 Continue Do 60 j=1,4 em(j) = qim(j)-beta(j)*kapm(j) 60 Continue kap = Sqrt(em(1)**2+em(2)**2) kapp = Sqrt(em(3)**2+em(4)**2) costh = (em(1)*em(3)+em(2)*em(4))/kap/kapp factor = Sqrt(epi(kap)*epi(kapp)*en(kap)*en(kapp)/(epi(k)*epi(kp)* 1enin*enout)) c run with shifted pi n subenergy( for cex) 70 eshift = ekape If (nifty(1).eq.1) eshift = eshift+nifty(11) If (nifty(1).eq.0.or.nifty(1).eq.8) eshift = eshift+nifty(12) If (nifty(1).eq.4.or.nifty(1).eq.7) eshift = eshift+nifty(11) If (mn.lt.1000.) Call tnoff (jj1,jj2,kapp,kap,eshift,kp,k,cthnuc) c deactivate call for now c ---- If(mn.gt.1000.)Call tDoff(kapp,kap,eshift,kp,k,cthnuc) x = costh pl2 = 1.5*x*x-.5 pl3 = 2.5*x**3-1.5*x c indepentent amplitudes Do 80 j=1,4 tofth(j) = factor*(bn(j)+x*bn(j+4)+pl2*bn(j+8)+pl3*bn(j+12)) 80 Continue If (nifty(6).ne.3) Return c dependent amplitudes rhl = factor*Sqrt(abs(1.-x*x)) If (abs(x).gt.1.) rhl = -rhl pl2 = 3.*x pl3 = 0.5*(15.*x*x-3.) Do 90 j=1,4 tofth(j+4) = rhl*(bnf(j+4)+bnf(j+8)*pl2+bnf(j+12)*pl3) 90 Continue Return c 100 format (1x,' cos thea pi-n gt 2 = ',e15.3) End