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genie::utils::kinematics::electromagnetic Namespace Reference

Functions

Range1D_t InelWLim (double El, double ml, double M)
Range1D_t InelQ2Lim_W (double El, double ml, double M, double W)
Range1D_t Inelq2Lim_W (double El, double ml, double M, double W)
Range1D_t InelQ2Lim (double El, double ml, double M)
Range1D_t Inelq2Lim (double El, double ml, double M)
Range1D_t InelXLim (double El, double ml, double M)
Range1D_t InelYLim (double El, double ml, double M)
Range1D_t InelYLim_X (double El, double ml, double M, double x)

Variables

static const double kMinQ2Limit = 0.02

Function Documentation

◆ InelQ2Lim()

Range1D_t genie::utils::kinematics::electromagnetic::InelQ2Lim ( double El,
double ml,
double M )

Definition at line 619 of file KineUtils.cxx.

621{
622// Computes Q2 (>0) limits irrespective of W for inelastic em interactions
623
624 Range1D_t Q2;
625 Q2.min = -1;
626 Q2.max = -1;
627
628 Range1D_t W = utils::kinematics::electromagnetic::InelWLim(El,ml,M);
629 if(W.min<0) return Q2;
630
631 Q2 = utils::kinematics::electromagnetic::InelQ2Lim_W(El,ml,M,W.min);
632 return Q2;
633}
genie::Range1D_t
A simple [min,max] interval for doubles.
Definition Range1.h:43
genie::utils::kinematics::electromagnetic::InelWLim
Range1D_t InelWLim(double El, double ml, double M)
Definition KineUtils.cxx:547
genie::utils::kinematics::electromagnetic::InelQ2Lim_W
Range1D_t InelQ2Lim_W(double El, double ml, double M, double W)
Definition KineUtils.cxx:569
genie::utils::kinematics::W
double W(const Interaction *const i)
Definition KineUtils.cxx:1101
genie::utils::kinematics::Q2
double Q2(const Interaction *const i)
Definition KineUtils.cxx:1077

References InelQ2Lim_W(), InelWLim(), genie::utils::kinematics::Q2(), and genie::utils::kinematics::W().

Referenced by Inelq2Lim(), and genie::KPhaseSpace::Q2Lim().

◆ Inelq2Lim()

Range1D_t genie::utils::kinematics::electromagnetic::Inelq2Lim ( double El,
double ml,
double M )

Definition at line 635 of file KineUtils.cxx.

637{
638// Computes Q2 (>0) limits irrespective of W for inelastic em interactions
639
640 Range1D_t Q2 = utils::kinematics::electromagnetic::InelQ2Lim(El,ml,M);
641 Range1D_t q2;
642 q2.min = - Q2.max;
643 q2.max = - Q2.min;
644 return q2;
645}
genie::Range1D_t::max
double max
Definition Range1.h:53
genie::Range1D_t::min
double min
Definition Range1.h:52
genie::utils::kinematics::electromagnetic::InelQ2Lim
Range1D_t InelQ2Lim(double El, double ml, double M)
Definition KineUtils.cxx:619

References InelQ2Lim(), genie::Range1D_t::max, genie::Range1D_t::min, and genie::utils::kinematics::Q2().

◆ InelQ2Lim_W()

Range1D_t genie::utils::kinematics::electromagnetic::InelQ2Lim_W ( double El,
double ml,
double M,
double W )

Definition at line 569 of file KineUtils.cxx.

571{
572// Computes Q2 limits (>0) @ the input W for inelastic em interactions
573
574 Range1D_t Q2;
575 Q2.min = -1;
576 Q2.max = -1;
577
578 double M2 = TMath::Power(M, 2.);
579 double ml2 = TMath::Power(ml, 2.);
580 double W2 = TMath::Power(W, 2.);
581 double s = M2 + 2*M*El + ml2; // added lepton mass squared to be used in s calculation (non-negligible mass for em interactions)
582
583 SLOG("KineLimits", pDEBUG) << "s = " << s;
584 SLOG("KineLimits", pDEBUG) << "El = " << El;
585 assert (s>0);
586
587 double auxC = 0.5*(s - M2 - ml2)/s; // subtract ml2 to account for the non-negligible mass of the incoming lepton
588 double aux1 = s + ml2 - W2;
589 double aux2 = aux1*aux1 - 4*s*ml2;
590
591 (aux2 < 0) ? ( aux2 = 0 ) : ( aux2 = TMath::Sqrt(aux2) );
592
593 Q2.max = -ml2 + auxC * (aux1 + aux2); // => 0
594 Q2.min = -ml2 + auxC * (aux1 - aux2); // => 0
595
596 // guard against overflows
597 Q2.max = TMath::Max(0., Q2.max);
598 Q2.min = TMath::Max(0., Q2.min);
599
600 // limit the minimum Q2
601 if(Q2.min < utils::kinematics::electromagnetic::kMinQ2Limit) {Q2.min = utils::kinematics::electromagnetic::kMinQ2Limit; } // use the relevant threshold for em scattering
602 if(Q2.max < Q2.min ) {Q2.min = -1; Q2.max = -1;}
603
604 return Q2;
605}
pDEBUG
#define pDEBUG
Definition Messenger.h:63
SLOG
#define SLOG(stream, priority)
A macro that returns the requested log4cpp::Category appending a short string (using the FUNCTION and...
Definition Messenger.h:84

References kMinQ2Limit, pDEBUG, genie::utils::kinematics::Q2(), SLOG, and genie::utils::kinematics::W().

Referenced by InelQ2Lim(), Inelq2Lim_W(), genie::KPhaseSpace::Q2Lim(), genie::KPhaseSpace::Q2Lim_W(), and genie::EmpiricalMECPXSec2015::XSec().

◆ Inelq2Lim_W()

Range1D_t genie::utils::kinematics::electromagnetic::Inelq2Lim_W ( double El,
double ml,
double M,
double W )

Definition at line 607 of file KineUtils.cxx.

609{
610// Computes q2 (<0) limits @ the input W for inelastic em interactions
611
612 Range1D_t Q2 = utils::kinematics::electromagnetic::InelQ2Lim_W(El,ml,M,W);
613 Range1D_t q2;
614 q2.min = - Q2.max;
615 q2.max = - Q2.min;
616 return q2;
617}

References InelQ2Lim_W(), genie::Range1D_t::max, genie::Range1D_t::min, genie::utils::kinematics::Q2(), and genie::utils::kinematics::W().

◆ InelWLim()

Range1D_t genie::utils::kinematics::electromagnetic::InelWLim ( double El,
double ml,
double M )

Definition at line 547 of file KineUtils.cxx.

548{
549// Computes W limits for inelastic em interactions
550//
551 double M2 = TMath::Power(M,2);
552 double ml2 = TMath::Power(ml,2); // added lepton mass squared to be used in s calculation
553 double s = M2 + 2*M*El + ml2; // non-negligible mass for em interactions
554 assert (s>0);
555
556 Range1D_t W;
557 W.min = kNeutronMass + kPhotontest;
558 W.max = TMath::Sqrt(s) - ml;
559 if(W.max<=W.min) {
560 W.min = -1;
561 W.max = -1;
562 return W;
563 }
564 W.min += controls::kASmallNum;
565 W.max -= controls::kASmallNum;
566 return W;
567}
genie::controls::kASmallNum
static const double kASmallNum
Definition Controls.h:40

References genie::controls::kASmallNum, genie::constants::kNeutronMass, genie::constants::kPhotontest, and genie::utils::kinematics::W().

Referenced by InelQ2Lim(), genie::KPhaseSpace::WLim(), and genie::EmpiricalMECPXSec2015::XSec().

◆ InelXLim()

Range1D_t genie::utils::kinematics::electromagnetic::InelXLim ( double El,
double ml,
double M )

Definition at line 647 of file KineUtils.cxx.

649{
650// Computes Bjorken x limits for inelastic em interactions
651
652 double M2 = TMath::Power(M, 2.);
653 double ml2 = TMath::Power(ml,2.);
654 double s = M2 + 2*M*El + ml2; // added lepton mass squared to be used in s calculation (non-negligible mass for em interactions)
655
656 SLOG("KineLimits", pDEBUG) << "s = " << s;
657 SLOG("KineLimits", pDEBUG) << "El = " << El;
658 assert (s > M2 + ml2); // added lepton mass squared to be used in s calculation (non-negligible mass for em interactions)
659
660 Range1D_t x;
661 x.min = ml2/(s - M2 - ml2) + controls::kASmallNum; // subtracted lepton mass squared to be used in s calculation (non-negligible mass for em interactions)
662 x.max = 1. - controls::kASmallNum;
663
664 return x;
665}

References genie::controls::kASmallNum, genie::Range1D_t::max, genie::Range1D_t::min, pDEBUG, and SLOG.

Referenced by InelYLim(), and genie::KPhaseSpace::XLim().

◆ InelYLim()

Range1D_t genie::utils::kinematics::electromagnetic::InelYLim ( double El,
double ml,
double M )

Definition at line 667 of file KineUtils.cxx.

668{
669// Computes y limits for inelastic v interactions
670
671 Range1D_t y;
672 y.min = 999;
673 y.max = -999;
674
675 Range1D_t xl = kinematics::electromagnetic::InelXLim(El,ml,M);
676 assert(xl.min>0 && xl.max>0);
677
678 const unsigned int N=100;
679 const double logxmin = TMath::Log10(xl.min);
680 const double logxmax = TMath::Log10(xl.max);
681 const double dlogx = (logxmax-logxmin) / (double)(N-1);
682
683 for(unsigned int i=0; i<N; i++) {
684 double x = TMath::Power(10, logxmin + i*dlogx);
685
686 Range1D_t y_x = kinematics::electromagnetic::InelYLim_X(El,ml,M,x);
687 if(y_x.min>=0 && y_x.min<=1) y.min = TMath::Min(y.min, y_x.min);
688 if(y_x.max>=0 && y_x.max<=1) y.max = TMath::Max(y.max, y_x.max);
689 }
690
691 if(y.max >= 0 && y.max <= 1 && y.min >= 0 && y.min <= 1) {
692 y.min = TMath::Max(y.min, controls::kASmallNum);
693 y.max = TMath::Min(y.max, 1 - controls::kASmallNum);
694 } else {
695 y.min = -1;
696 y.max = -1;
697 }
698 SLOG("KineLimits", pDEBUG) << "y = [" << y.min << ", " << y.max << "]";
699 return y;
700}
genie::utils::kinematics::electromagnetic::InelXLim
Range1D_t InelXLim(double El, double ml, double M)
Definition KineUtils.cxx:647
genie::utils::kinematics::electromagnetic::InelYLim_X
Range1D_t InelYLim_X(double El, double ml, double M, double x)
Definition KineUtils.cxx:702

References InelXLim(), InelYLim_X(), genie::controls::kASmallNum, genie::Range1D_t::max, genie::Range1D_t::min, pDEBUG, and SLOG.

Referenced by genie::KPhaseSpace::YLim().

◆ InelYLim_X()

Range1D_t genie::utils::kinematics::electromagnetic::InelYLim_X ( double El,
double ml,
double M,
double x )

Definition at line 702 of file KineUtils.cxx.

705{
706// Computes y limits @ the input x for inelastic em interactions
707
708 Range1D_t y;
709 y.min = -1;
710 y.max = -1;
711
712 double El2 = TMath::Power(El,2);
713 double ml2 = TMath::Power(ml,2);
714
715 SLOG("KineLimits", pDEBUG) << "x = " << x;
716 SLOG("KineLimits", pDEBUG) << "El = " << El;
717
718 assert (El>0);
719 assert (x>0&&x<1);
720
721 double a = 0.5 * ml2/(M*El*x);
722 double b = ml2/El2;
723 double c = 1 + 0.5*x*M/El;
724 double d = TMath::Max(0., TMath::Power(1-a,2.) - b);
725
726 double A = 0.5 * (1-a-0.5*b)/c;
727 double B = 0.5 * TMath::Sqrt(d)/c;
728
729 y.min = TMath::Max(0., A-B) + controls::kASmallNum;
730 y.max = TMath::Min(1., A+B) - controls::kASmallNum;
731
732 return y;
733}
a
const double a
Definition gUpMuFluxGen.cxx:164

References a, genie::controls::kASmallNum, genie::Range1D_t::max, genie::Range1D_t::min, pDEBUG, and SLOG.

Referenced by InelYLim(), and genie::KPhaseSpace::YLim_X().

Variable Documentation

◆ kMinQ2Limit

const double genie::utils::kinematics::electromagnetic::kMinQ2Limit = 0.02
static

Definition at line 114 of file KineUtils.h.

Referenced by genie::RESKinematicsGenerator::ComputeMaxXSec(), and InelQ2Lim_W().

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