1 //--------------------------------------------------------------------------
4 // This software is part of the EvtGen package developed jointly
5 // for the BaBar and CLEO collaborations. If you use all or part
6 // of it, please give an appropriate acknowledgement.
8 // Copyright Information: See EvtGen/COPYRIGHT
9 // Copyright (C) 1998 Caltech, UCSB
11 // Module: EvtbTosllAmp.cc
13 // Description: Routine to implement semileptonic decays to pseudo-scalar
16 // Modification history:
18 // DJL April 17,1998 Module created
20 //------------------------------------------------------------------------
22 #include "EvtGenBase/EvtPatches.hh"
23 #include "EvtGenBase/EvtPatches.hh"
24 #include "EvtGenBase/EvtParticle.hh"
25 #include "EvtGenBase/EvtGenKine.hh"
26 #include "EvtGenBase/EvtPDL.hh"
27 #include "EvtGenBase/EvtReport.hh"
28 #include "EvtGenBase/EvtVector4C.hh"
29 #include "EvtGenBase/EvtTensor4C.hh"
30 #include "EvtGenBase/EvtDiracSpinor.hh"
31 #include "EvtGenModels/EvtbTosllAmp.hh"
32 #include "EvtGenBase/EvtId.hh"
33 #include "EvtGenBase/EvtAmp.hh"
34 #include "EvtGenBase/EvtScalarParticle.hh"
35 #include "EvtGenBase/EvtVectorParticle.hh"
36 #include "EvtGenBase/EvtDiLog.hh"
38 double EvtbTosllAmp::CalcMaxProb( EvtId parent, EvtId meson,
39 EvtId lepton1, EvtId lepton2,
40 EvtbTosllFF *FormFactors,
43 //This routine takes the arguements parent, meson, and lepton
44 //number, and a form factor model, and returns a maximum
45 //probability for this semileptonic form factor model. A
46 //brute force method is used. The 2D cos theta lepton and
47 //q2 phase space is probed.
49 //Start by declaring a particle at rest.
51 //It only makes sense to have a scalar parent. For now.
52 //This should be generalized later.
54 EvtScalarParticle *scalar_part;
55 EvtParticle *root_part;
57 scalar_part=new EvtScalarParticle;
59 //cludge to avoid generating random numbers!
60 scalar_part->noLifeTime();
64 p_init.set(EvtPDL::getMass(parent),0.0,0.0,0.0);
65 scalar_part->init(parent,p_init);
66 root_part=(EvtParticle *)scalar_part;
67 root_part->setDiagonalSpinDensity();
69 EvtParticle *daughter, *lep1, *lep2;
75 listdaug[1] = lepton1;
76 listdaug[2] = lepton2;
78 amp.init(parent,3,listdaug);
80 root_part->makeDaughters(3,listdaug);
81 daughter=root_part->getDaug(0);
82 lep1=root_part->getDaug(1);
83 lep2=root_part->getDaug(2);
85 //cludge to avoid generating random numbers!
86 daughter->noLifeTime();
91 //Initial particle is unpolarized, well it is a scalar so it is
94 rho.setDiag(root_part->getSpinStates());
98 double m = root_part->mass();
100 EvtVector4R p4meson, p4lepton1, p4lepton2, p4w;
103 double q2, elepton, plepton;
105 double erho,prho,costl;
107 double maxfoundprob = 0.0;
113 for (massiter=0;massiter<3;massiter++){
115 mass[0] = EvtPDL::getMeanMass(meson);
116 mass[1] = EvtPDL::getMeanMass(lepton1);
117 mass[2] = EvtPDL::getMeanMass(lepton2);
119 mass[0] = EvtPDL::getMinMass(meson);
122 mass[0] = EvtPDL::getMaxMass(meson);
123 if ( (mass[0]+mass[1]+mass[2])>m) mass[0]=m-mass[1]-mass[2]-0.00001;
126 q2max = (m-mass[0])*(m-mass[0]);
129 //cout << "m " << m << "mass[0] " << mass[0] << " q2max "<< q2max << endl;
131 //want to avoid picking up the tail of the photon propagator
132 q2 = ((i+1.5)*q2max)/26.0;
134 if (i==0) q2=4*(mass[1]*mass[1]);
136 erho = ( m*m + mass[0]*mass[0] - q2 )/(2.0*m);
138 prho = sqrt(erho*erho-mass[0]*mass[0]);
140 p4meson.set(erho,0.0,0.0,-1.0*prho);
141 p4w.set(m-erho,0.0,0.0,prho);
143 //This is in the W rest frame
144 elepton = (q2+mass[1]*mass[1])/(2.0*sqrt(q2));
145 plepton = sqrt(elepton*elepton-mass[1]*mass[1]);
151 costl = 0.99*(j - 1.0);
153 //These are in the W rest frame. Need to boost out into
155 p4lepton1.set(elepton,0.0,
156 plepton*sqrt(1.0-costl*costl),plepton*costl);
157 p4lepton2.set(elepton,0.0,
158 -1.0*plepton*sqrt(1.0-costl*costl),-1.0*plepton*costl);
160 EvtVector4R boost((m-erho),0.0,0.0,1.0*prho);
161 p4lepton1=boostTo(p4lepton1,boost);
162 p4lepton2=boostTo(p4lepton2,boost);
164 //Now initialize the daughters...
166 daughter->init(meson,p4meson);
167 lep1->init(lepton1,p4lepton1);
168 lep2->init(lepton2,p4lepton2);
170 CalcAmp(root_part,amp,FormFactors);
172 //Now find the probability at this q2 and cos theta lepton point
173 //and compare to maxfoundprob.
175 //Do a little magic to get the probability!!
177 //cout <<"amp:"<<amp.getSpinDensity()<<endl;
179 prob = rho.normalizedProb(amp.getSpinDensity());
181 //cout << "prob:"<<q2<<" "<<costl<<" "<<prob<<endl;
186 //probclt contains prob at ctl=-1,0,1.
187 //prob=a+b*ctl+c*ctl^2
190 double b=0.5*(probctl[2]-probctl[0]);
191 double c=0.5*(probctl[2]+probctl[0])-probctl[1];
194 if (probctl[1]>prob) prob=probctl[1];
195 if (probctl[2]>prob) prob=probctl[2];
198 double ctlx=-0.5*b/c;
200 double probtmp=a+b*ctlx+c*ctlx*ctlx;
201 if (probtmp>prob) prob=probtmp;
206 //report(DEBUG,"EvtGen") << "prob,probctl:"<<prob<<" "
207 // << probctl[0]<<" "
208 // << probctl[1]<<" "
209 // << probctl[2]<<endl;
216 if ( prob > maxfoundprob ) {
220 //cout << "q2,maxfoundprob:"<<q2<<" "<<maxfoundprob<<endl;
223 if ( EvtPDL::getWidth(meson) <= 0.0 ) {
224 //if the particle is narrow dont bother with changing the mass.
230 root_part->deleteTree();
232 poleSize=0.04*(maxpole/maxfoundprob)*4*(mass[1]*mass[1]);
236 //cout <<"maxfoundprob,maxpole,poleSize:"<<maxfoundprob<<" "
237 // <<maxpole<<" "<<poleSize<<endl;
246 EvtComplex EvtbTosllAmp::GetC7Eff(double q2, bool nnlo)
249 if (!nnlo) return -0.313;
251 double shat = q2/mbeff/mbeff;
264 A9 = 4.287 + (-0.218);
266 A10 = -4.592 + 0.379;
279 Lmu = log(muscale/mbeff);
281 EvtComplex uniti(0.0,1.0);
293 // change energy scale to 5.0 for full NNLO calculation below shat = 0.25
298 A9 = 4.174 + (-0.035);
299 A10 = -4.592 + 0.379;
305 Lmu = log(muscale/mbeff);
309 EvtComplex k7100(-0.68192,-0.074998);
310 EvtComplex k7101(0.0,0.0);
311 EvtComplex k7110(-0.23935,-0.12289);
312 EvtComplex k7111(0.0027424,0.019676);
313 EvtComplex k7120(-0.0018555,-0.175);
314 EvtComplex k7121(0.022864,0.011456);
315 EvtComplex k7130(0.28248,-0.12783);
316 EvtComplex k7131(0.029027,-0.0082265);
317 f71 = k7100 + k7101*logshat + shat*(k7110 + k7111*logshat) +
318 shat*shat*(k7120 + k7121*logshat) +
319 shat*shat*shat*(k7130 + k7131*logshat);
320 F71 = (-208.0/243.0)*Lmu + f71;
324 EvtComplex k7200(4.0915,0.44999);
325 EvtComplex k7201(0.0,0.0);
326 EvtComplex k7210(1.4361,0.73732);
327 EvtComplex k7211(-0.016454,-0.11806);
328 EvtComplex k7220(0.011133,1.05);
329 EvtComplex k7221(-0.13718,-0.068733);
330 EvtComplex k7230(-1.6949,0.76698);
331 EvtComplex k7231(-0.17416,0.049359);
332 f72 = k7200 + k7201*logshat + shat*(k7210 + k7211*logshat) +
333 shat*shat*(k7220 + k7221*logshat) +
334 shat*shat*shat*(k7230 + k7231*logshat);
335 F72 = (416.0/81.0)*Lmu + f72;
338 F78 = (-32.0/9.0)*Lmu + 8.0*EvtConst::pi*EvtConst::pi/27.0 + (-44.0/9.0)
339 + (-8.0*EvtConst::pi/9.0)*uniti +
340 (4.0/3.0*EvtConst::pi*EvtConst::pi - 40.0/3.0)*shat +
341 (32.0*EvtConst::pi*EvtConst::pi/9.0 - 316.0/9.0)*shat*shat +
342 (200.0*EvtConst::pi*EvtConst::pi/27.0 - 658.0/9.0)*shat*shat*shat +
343 (-8.0*logshat/9.0)*(shat + shat*shat + shat*shat*shat);
345 c7eff = A7 - alphas/(4.0*EvtConst::pi)*(C1*F71 + C2*F72 + A8*F78);
351 EvtComplex EvtbTosllAmp::GetC9Eff(double q2, bool nnlo, bool btod)
354 if (!nnlo) return 4.344;
356 double shat = q2/mbeff/mbeff;
371 A9 = 4.287 + (-0.218);
373 A10 = -4.592 + 0.379;
386 Lmu = log(muscale/mbeff);
389 EvtComplex uniti(0.0,1.0);
393 xarg = 4.0*mchat/shat;
394 hc = -4.0/9.0*log(mchat*mchat) + 8.0/27.0 + 4.0*xarg/9.0;
398 hc = hc - 2.0/9.0*(2.0 + xarg)*sqrt(fabs(1.0 - xarg))*
399 (log(fabs((sqrt(1.0 - xarg)+1.0)/(sqrt(1.0 - xarg) - 1.0))) -
404 hc = hc - 2.0/9.0*(2.0 + xarg)*sqrt(fabs(1.0 - xarg))*
405 2.0*atan(1.0/sqrt(xarg - 1.0));
410 h1 = 8.0/27.0 + 4.0*xarg/9.0;
413 h1 = h1 - 2.0/9.0*(2.0 + xarg)*sqrt(fabs(1.0 - xarg))*
414 (log(fabs((sqrt(1.0 - xarg)+1.0)/(sqrt(1.0 - xarg) - 1.0))) -
419 h1 = h1 - 2.0/9.0*(2.0 + xarg)*sqrt(fabs(1.0 - xarg))*
420 2.0*atan(1.0/sqrt(xarg - 1.0));
425 h0 = 8.0/27.0 - 4.0*log(2.0)/9.0 + 4.0*uniti*EvtConst::pi/9.0;
428 // X=V_{ud}^* V_ub / V_{td}^* V_tb * (4/3 C_1 +C_2) * (h(\hat m_c^2, hat s)-
429 // h(\hat m_u^2, hat s))
430 EvtComplex Vudstar(1.0 - 0.2279*0.2279/2.0, 0.0);
431 EvtComplex Vub((0.118+0.273)/2.0, -1.0*(0.305+0.393)/2.0);
432 EvtComplex Vtdstar(1.0 - (0.118+0.273)/2.0,(0.305+0.393)/2.0);
433 EvtComplex Vtb(1.0,0.0);
436 Xd = (Vudstar * Vub / Vtdstar * Vtb) * (4.0/3.0*C1 + C2) * (hc - h0);
439 EvtComplex c9eff=4.344;
442 c9eff = A9 + T9*hc + U9*h1 + W9*h0;
451 // change energy scale to 5.0 for full NNLO calculation below shat = 0.25
454 A9 = 4.174 + (-0.035);
461 Lmu = log(muscale/mbeff);
465 EvtComplex k9100(-11.973,0.16371);
466 EvtComplex k9101(-0.081271,-0.059691);
467 EvtComplex k9110(-28.432,-0.25044);
468 EvtComplex k9111(-0.040243,0.016442);
469 EvtComplex k9120(-57.114,-0.86486);
470 EvtComplex k9121(-0.035191,0.027909);
471 EvtComplex k9130(-128.8,-2.5243);
472 EvtComplex k9131(-0.017587,0.050639);
473 f91 = k9100 + k9101*logshat + shat*(k9110 + k9111*logshat) +
474 shat*shat*(k9120 + k9121*logshat) +
475 shat*shat*shat*(k9130 + k9131*logshat);
476 F91 = (-1424.0/729.0 + 16.0*uniti*EvtConst::pi/243.0
477 + 64.0/27.0*log(mchat))*Lmu - 16.0*Lmu*logshat/243.0 +
478 (16.0/1215.0 - 32.0/135.0/mchat/mchat)*Lmu*shat +
479 (4.0/2835.0 - 8.0/315.0/mchat/mchat/mchat/mchat)*Lmu*shat*shat +
480 (16.0/76545.0 - 32.0/8505.0/mchat/mchat/mchat/mchat/mchat/mchat)*
481 Lmu*shat*shat*shat -256.0*Lmu*Lmu/243.0 + f91;
485 EvtComplex k9200(6.6338,-0.98225);
486 EvtComplex k9201(0.48763,0.35815);
487 EvtComplex k9210(3.3585,1.5026);
488 EvtComplex k9211(0.24146,-0.098649);
489 EvtComplex k9220(-1.1906,5.1892);
490 EvtComplex k9221(0.21115,-0.16745);
491 EvtComplex k9230(-17.12,15.146);
492 EvtComplex k9231(0.10552,-0.30383);
493 f92 = k9200 + k9201*logshat + shat*(k9210 + k9211*logshat) +
494 shat*shat*(k9220 + k9221*logshat) +
495 shat*shat*shat*(k9230 + k9231*logshat);
496 F92 = (256.0/243.0 - 32.0*uniti*EvtConst::pi/81.0
497 - 128.0/9.0*log(mchat))*Lmu + 32.0*Lmu*logshat/81.0 +
498 (-32.0/405.0 + 64.0/45.0/mchat/mchat)*Lmu*shat +
499 (-8.0/945.0 + 16.0/105.0/mchat/mchat/mchat/mchat)*Lmu*shat*shat +
500 (-32.0/25515.0 + 64.0/2835.0/mchat/mchat/mchat/mchat/mchat/mchat)*
501 Lmu*shat*shat*shat + 512.0*Lmu*Lmu/81.0 + f92;
504 F98 = 104.0/9.0 - 32.0*EvtConst::pi*EvtConst::pi/27.0 +
505 (1184.0/27.0 - 40.0*EvtConst::pi*EvtConst::pi/9.0)*shat +
506 (14212.0/135.0 - 32.0*EvtConst::pi*EvtConst::pi/3.0)*shat*shat +
507 (193444.0/945.0 - 560.0*EvtConst::pi*EvtConst::pi/27.0)*shat*shat*shat +
508 16.0*logshat/9.0*(1.0 + shat + shat*shat + shat*shat*shat);
510 Xd = (Vudstar * Vub / Vtdstar * Vtb) * (4.0/3.0*C1 + C2) * (hc - h0);
512 c9eff = A9 + T9*hc + U9*h1 + W9*h0 -
513 alphas/(4.0*EvtConst::pi)*(C1*F91 + C2*F92 + A8*F98);
522 EvtComplex EvtbTosllAmp::GetC10Eff(double /*q2*/, bool nnlo)
525 if (!nnlo) return -4.669;
527 A10 = -4.592 + 0.379;
535 double EvtbTosllAmp::dGdsProb(double mb, double ms, double ml,
538 // Compute the decay probability density function given a value of s
539 // according to Ali's paper
542 double delta, lambda, prob;
543 double f1, f2, f3, f4;
550 EvtComplex c9eff = EvtbTosllAmp::GetC9Eff(sh*mb);
551 EvtComplex c7eff = EvtbTosllAmp::GetC7Eff(sh*mb);
552 EvtComplex c10eff = EvtbTosllAmp::GetC10Eff(sh*mb);
554 double alphas = 0.119/
555 (1 + 0.119*log(pow(4.8,2)/pow(91.1867,2))*23.0/12.0/EvtConst::pi);
556 double omega9 = -2.0/9.0*EvtConst::pi*EvtConst::pi - 4.0/3.0*EvtDiLog::DiLog(sh)
557 - 2.0/3.0*log(sh)*log(1.0-sh)
558 - (5.0+4.0*sh)/(3.0*(1.0+2.0*sh)) * log(1.0-sh)
559 - 2.0*sh*(1.0+sh)*(1.0-2.0*sh)
560 /(3.0*pow(1.0-sh,2)*(1.0+2.0*sh)) * log(sh)
561 + (5.0+9.0*sh-6.0*sh*sh)/(6.0*(1.0-sh)*(1.0+2.0*sh));
562 double eta9 = 1.0 + alphas*omega9/EvtConst::pi;
563 double omega7 = -8.0/3.0*log(4.8/mb)
564 -4.0/3.0*EvtDiLog::DiLog(sh)
565 -2.0/9.0*EvtConst::pi*EvtConst::pi
566 -2.0/3.0*log(sh)*log(1.0-sh)
567 -log(1-sh)*(8.0+sh)/(2.0+sh)/3.0
568 -2.0/3.0*sh*(2.0 - 2.0*sh - sh*sh)*log(sh)/pow((1.0 - sh),2)/(2.0 + sh)
569 -(16.0 - 11.0*sh - 17.0*sh*sh)/18.0/(2.0 + sh)/(1.0 - sh);
570 double eta7 = 1.0 + alphas*omega7/EvtConst::pi;
572 double omega79 = -4.0/3.0*log(4.8/mb)
573 -4.0/3.0*EvtDiLog::DiLog(sh)
574 -2.0/9.0*EvtConst::pi*EvtConst::pi
575 -2.0/3.0*log(sh)*log(1.0-sh)
576 -1.0/9.0*(2.0+7.0*sh)*log(1.0 - sh)/sh
577 -2.0/9.0*sh*(3.0 - 2.0*sh)*log(sh)/pow((1.0 - sh),2)
578 +1.0/18.0*(5.0 - 9.0*sh)/(1.0 - sh);
579 double eta79 = 1.0 + alphas*omega79/EvtConst::pi;
581 double c7c9 = abs(c7eff)*real(c9eff);
582 c7c9 *= pow(eta79,2);
583 double c7c7 = pow(abs(c7eff),2);
586 double c9c9plusc10c10 = pow(abs(c9eff),2) + pow(abs(c10eff),2);
587 c9c9plusc10c10 *= pow(eta9,2);
588 double c9c9minusc10c10 = pow(abs(c9eff),2) - pow(abs(c10eff),2);
589 c9c9minusc10c10 *= pow(eta9,2);
591 lambda = 1.0 + sh*sh + pow(msh,4) - 2.0*(sh + sh*msh*msh + msh*msh);
593 f1 = pow(1.0-msh*msh,2) - sh*(1.0 + msh*msh);
594 f2 = 2.0*(1.0 + msh*msh) * pow(1.0-msh*msh,2)
595 - sh*(1.0 + 14.0*msh*msh + pow(msh,4)) - sh*sh*(1.0 + msh*msh);
596 f3 = pow(1.0-msh*msh,2) + sh*(1.0 + msh*msh) - 2.0*sh*sh
597 + lambda*2.0*mlh*mlh/sh;
598 f4 = 1.0 - sh + msh*msh;
600 delta = ( 12.0*c7c9*f1 + 4.0*c7c7*f2/sh ) * (1.0 + 2.0*mlh*mlh/sh)
602 + 6.0*mlh*mlh*c9c9minusc10c10*f4;
604 prob = sqrt(lambda*(1.0 - 4.0*mlh*mlh/sh)) * delta;
609 double EvtbTosllAmp::dGdsdupProb(double mb, double ms, double ml,
612 // Compute the decay probability density function given a value of s and u
613 // according to Ali's paper
616 double f1sp, f2sp, f3sp;
618 double sh = s / (mb*mb);
620 EvtComplex c9eff = EvtbTosllAmp::GetC9Eff(sh*mb);
621 EvtComplex c7eff = EvtbTosllAmp::GetC7Eff(sh*mb);
622 EvtComplex c10eff = EvtbTosllAmp::GetC10Eff(sh*mb);
624 double alphas = 0.119/
625 (1 + 0.119*log(pow(4.8,2)/pow(91.1867,2))*23.0/12.0/EvtConst::pi);
626 double omega9 = - 2.0/9.0*EvtConst::pi*EvtConst::pi - 4.0/3.0*EvtDiLog::DiLog(sh)
627 - 2.0/3.0*log(sh)*log(1.0-sh)
628 - (5.0+4.0*sh)/(3.0*(1.0+2.0*sh)) * log(1.0-sh)
629 - 2.0*sh*(1.0+sh)*(1.0-2.0*sh)
630 /(3.0*pow(1.0-sh,2)*(1.0+2.0*sh)) * log(sh)
631 + (5.0+9.0*sh-6.0*sh*sh)/(6.0*(1.0-sh)*(1.0+2.0*sh));
632 double eta9 = 1.0 + alphas*omega9/EvtConst::pi;
633 double omega7 = -8.0/3.0*log(4.8/mb)
634 -4.0/3.0*EvtDiLog::DiLog(sh)
635 -2.0/9.0*EvtConst::pi*EvtConst::pi
636 -2.0/3.0*log(sh)*log(1.0-sh)
637 -log(1-sh)*(8.0+sh)/(2.0+sh)/3.0
638 -2.0/3.0*sh*(2.0 - 2.0*sh - sh*sh)*log(sh)/pow((1.0 - sh),2)/(2.0 + sh)
639 -(16.0 - 11.0*sh - 17.0*sh*sh)/18.0/(2.0 + sh)/(1.0 - sh);
640 double eta7 = 1.0 + alphas*omega7/EvtConst::pi;
642 double omega79 = -4.0/3.0*log(4.8/mb)
643 -4.0/3.0*EvtDiLog::DiLog(sh)
644 -2.0/9.0*EvtConst::pi*EvtConst::pi
645 -2.0/3.0*log(sh)*log(1.0-sh)
646 -1.0/9.0*(2.0+7.0*sh)*log(1.0 - sh)/sh
647 -2.0/9.0*sh*(3.0 - 2.0*sh)*log(sh)/pow((1.0 - sh),2)
648 +1.0/18.0*(5.0 - 9.0*sh)/(1.0 - sh);
649 double eta79 = 1.0 + alphas*omega79/EvtConst::pi;
651 double c7c9 = abs(c7eff)*real(c9eff);
652 c7c9 *= pow(eta79,2);
653 double c7c7 = pow(abs(c7eff),2);
656 double c9c9plusc10c10 = pow(abs(c9eff),2) + pow(abs(c10eff),2);
657 c9c9plusc10c10 *= pow(eta9,2);
658 double c9c9minusc10c10 = pow(abs(c9eff),2) - pow(abs(c10eff),2);
659 c9c9minusc10c10 *= pow(eta9,2);
660 double c7c10 = abs(c7eff)*real(c10eff);
661 c7c10 *= eta7; c7c10 *= eta9;
662 double c9c10 = real(c9eff)*real(c10eff);
663 c9c10 *= pow(eta9,2);
665 f1sp = ( pow(mb*mb-ms*ms,2) - s*s) * c9c9plusc10c10
666 + 4.0*( pow(mb,4) - ms*ms*mb*mb - pow(ms,4)*(1.0 - ms*ms/(mb*mb))
667 - 8.0*s*ms*ms - s*s*(1.0 + ms*ms/(mb*mb) ))*mb*mb*c7c7/s
670 - 8.0*(s*(mb*mb + ms*ms) - pow(mb*mb-ms*ms,2)) * c7c9
672 *(1.0 + 2.0*ml*ml/s);
674 f2sp = 4.0*s*c9c10 + 8.0*(mb*mb + ms*ms)*c7c10;
675 f3sp = - (c9c9plusc10c10)
676 + 4.0*(1.0 + pow(ms/mb,4)) * mb*mb*c7c7/s
678 *(1.0 + 2.0*ml*ml/s);
680 prob = (f1sp + f2sp*u + f3sp*u*u)/ pow(mb,3);