#include <CMSCGEN.h>

Public Member Functions
	CMSCGEN ()

double	cos_theta ()

double	dNdEmudEnu (double Enu, double Emu, double theta)

double	flux ()

int	generate ()

int	generateNuMu ()

int	initialize (double, double, double, double, CLHEP::HepRandomEngine *, bool, bool)

int	initialize (double, double, double, double, int, bool, bool)

int	initializeNuMu (double, double, double, double, double, double, double, double, double, CLHEP::HepRandomEngine *)

int	initializeNuMu (double, double, double, double, double, double, double, double, double, int)

double	momentum_times_charge ()

	~CMSCGEN ()

Public Attributes
double	AR

double	dNdEmudEnuMax

double	negabs

double	negfrac

double	ProdAlt

double	Rnunubar

double	sigma

Private Attributes
double	b0

double	b0c [3]

double	b1

double	b1c [3]

double	b2

double	b2c [3]

double	c

double	c1

double	c2

double	cemax

double	cmax

double	cmax_in

double	cmax_max

double	cmax_min

double	cmin

double	cmin_in

double	corr [101]

bool	delRanGen

double	enumax

double	enumin

int	initialization

double	integrated_flux

double	Lfac

double	Lmax

double	Lmin

double	pe [9]

double	pmax

double	pmin

double	pmin_max

double	pmin_min

double	pq

CLHEP::HepRandomEngine *	RanGen2

bool	TIFOnly_const

bool	TIFOnly_lin

double	xemax

double	xemin

Detailed Description

Definition at line 30 of file CMSCGEN.h.

Constructor & Destructor Documentation

CMSCGEN::CMSCGEN ( )

Definition at line 13 of file CMSCGEN.cc.

                  : initialization(0), RanGen2(0), delRanGen(false)
 {
 }

CMSCGEN::~CMSCGEN ( )

Definition at line 17 of file CMSCGEN.cc.

References delRanGen, and RanGen2.

 {
   if (delRanGen)
     delete RanGen2;
 }

Member Function Documentation

double CMSCGEN::cos_theta ( )

Definition at line 462 of file CMSCGEN.cc.

References c, gather_cfg::cout, and initialization.

Referenced by CosmicMuonGenerator::nextEvent().

 {
   
   if(initialization==1)
     { 
       // here convert between coordinate systems:
       return -c;
     }
   else
     {
       std::cout << " >>> CMSCGEN <<< warning: not initialized" << std::endl;
       return -0.9999;
     }
 
 }

double CMSCGEN::dNdEmudEnu	(	double	Enu,
		double	Emu,
		double	theta
	)

Definition at line 577 of file CMSCGEN.cc.

References alpha, AR, funct::cos(), epsilon, N_A, funct::pow(), ProdAlt, Rearth, sigma, funct::sin(), and SurfaceOfEarth.

Referenced by generateNuMu(), and initializeNuMu().

                                                                 {
   double cthetaNu = 1. + ctheta; //swap cos(theta) from down to up range
   double thetas = asin(sin(acos(cthetaNu))*(Rearth-SurfaceOfEarth)/(Rearth+ProdAlt));
   double costhetas = cos(thetas);
   double dNdEnudW = 0.0286*pow(Enu,-2.7)*(1./(1.+(6.*Enu*costhetas)/115.)+0.213/(1.+(1.44*Enu*costhetas)/850.)); //cm^2*s*sr*GeV
   double dNdEmudEnu = N_A*sigma/alpha*dNdEnudW*1./(1.+Emu/epsilon)*
     (Enu-Emu+AR/3*(Enu*Enu*Enu-Emu*Emu*Emu)/(Enu*Enu));
   return dNdEmudEnu;
 }

double CMSCGEN::flux ( )

Definition at line 478 of file CMSCGEN.cc.

References gather_cfg::cout, initialization, and integrated_flux.

 {
   
   if(initialization==1)
     { 
       return integrated_flux;
     }
   else
     {
       std::cout << " >>> CMSCGEN <<< warning: not initialized" << std::endl;
       return -0.9999;
     }
   
 }

int CMSCGEN::generate ( )

Definition at line 256 of file CMSCGEN.cc.

References b0, b0c, b1, b1c, b2, b2c, c, cemax, cmax, cmin, corr, gather_cfg::cout, alignCSCRings::e, initialization, gen::k, dttmaxenums::L, Lfac, Lmin, siStripFEDMonitor_P5_cff::Max, siStripFEDMonitor_P5_cff::Min, pe, pq, diffTwoXMLs::r1, diffTwoXMLs::r2, RanGen2, mathSSE::sqrt(), TIFOnly_const, TIFOnly_lin, xemax, xemin, and detailsBasic3DVector::z.

Referenced by CosmicMuonGenerator::nextEvent().

 {
 
   if(initialization==0)
     {
       std::cout << " >>> CMSCGEN <<< warning: not initialized" << std::endl;
       return -1;
     }
   
   // note: use historical notation (fortran version l3cgen.f)
 
   //
   // +++ determine x = 1/e**2
   //
   //  explanation: the energy distribution 
   //        dn/d(1/e**2) = dn/de * e**3 = dn/dlog10(e) * e**2
   //     is parametrized by a polynomial. accordingly xe = 1/e**2 is sampled
   //     and e calculated 
   //
   //     need precise random variable with high precison since for 
   //     emin = 3 GeV energies around 3000 GeV are very rare!
   //
 
   double r1, r2, r3;
   double xe, e, ce, L, L2;
   int k;    
   double prob; 
   
   double c_max;
   double z, z_max;
   
   while (1)
     {
       prob = RanGen2->flat();
       r1 = double(prob);
       prob = RanGen2->flat();
       r2 = double(prob);
       
       xe = xemin+r1*(xemax-xemin);
       
       if( (1./sqrt(xe)<3) && TIFOnly_const == true) { //generate constant energy dependence for E<2GeV, only used for TIF
     //compute constant to match to CMSCGEN spectrum
     e=3.;      
     L = log10(e);
     L2 = L*L;
     
     ce = (((((((pe[8]*L
             +pe[7])*L
            +pe[6])*L
           +pe[5])*L
          +pe[4])*L
         +pe[3])*L
            +pe[2])*L
           +pe[1])*L
       +pe[0];
     
     k = int ((L-Lmin)*Lfac+1.);
     k = TMath::Max(1,TMath::Min(k,100));
     ce = ce * corr[k];
     
     e = 1./sqrt(xe);  
     if(r2 < ( e*e*e*ce/(cemax*3.*3.*3.) )) break;
       
       }else if( (1./sqrt(xe)<3) && TIFOnly_lin == true) { //generate linear energy dependence for E<2GeV, only used for TIF
     //compute constant to match to CMSCGEN spectrum
     e=3.;      
     L = log10(e);
     L2 = L*L;
     
     ce = (((((((pe[8]*L
             +pe[7])*L
            +pe[6])*L
           +pe[5])*L
          +pe[4])*L
         +pe[3])*L
            +pe[2])*L
           +pe[1])*L
       +pe[0];
       
     k = int ((L-Lmin)*Lfac+1.);
     k = TMath::Max(1,TMath::Min(k,100));
     ce = ce * corr[k];
       
     e = 1./sqrt(xe);  
     if(r2 < ( e*e*e*e*ce/(cemax*3.*3.*3.*3.) )) break;
       
       }else{ //this is real CMSCGEN energy-dependence
 
     e = 1./sqrt(xe);       
     L = log10(e);
     L2 = L*L;
     
     ce = (((((((pe[8]*L
             +pe[7])*L
            +pe[6])*L
           +pe[5])*L
          +pe[4])*L
         +pe[3])*L
            +pe[2])*L
           +pe[1])*L
       +pe[0];
     
     k = int ((L-Lmin)*Lfac+1.);
     k = TMath::Max(1,TMath::Min(k,100));
     ce = ce * corr[k];
     
     if(cemax*r2 < ce) break;
 
       } //end of CMSCGEN energy-dependence
     } //end of while
   
   pq = e;
   
   //
   // +++ charge ratio 1.280
   //
   prob = RanGen2->flat();
   r3 = double(prob);
   
   double charg = 1.;
   if(r3 < 0.439) charg=-1.;
   
   pq = pq*charg;
   
   //
   //  +++ determine cos(angle)
   //
   //  simple trial and rejection method
   //
   
   // first calculate energy dependent coefficients b_i
 
   if(TIFOnly_const == true && e<3.){ //forTIF (when E<2GeV use angles of 2GeV cosmic)
     L = log10(3.);
     L2 = L*L;
   }
   if(TIFOnly_lin == true && e<3.){ //forTIF (when E<2GeV use angles of 2GeV cosmic)
     L = log10(3.);
     L2 = L*L; 
   }
   
   b0 = b0c[0] + b0c[1] * L + b0c[2]* L2;
   b1 = b1c[0] + b1c[1] * L + b1c[2]* L2;
   b2 = b2c[0] + b2c[1] * L + b2c[2]* L2;
   
   //
   // need to know the maximum of z(c)
   //
   // first calculate c for which c distribution z(c) = maximum 
   // 
   // (note: maximum of curve is NOT always at c = -1, but never at c = -0.1)   
   //
   
   // try extremal value (from z'(c) = 0), but only if z''(c) < 0  
   //
   // z'(c) = b1 + b2 * c   =>  at c_max = - b1 / (2 b_2) is z'(c) = 0
   //
   // z''(c) = b2 
   
   c_max = -1.;
   
   if(b2<0.) {
     c_max = - 0.5 * b1/b2;
     if(c_max < -1.) c_max = -1.;
     if(c_max > -0.1) c_max = -0.1;
   } 
   
   z_max = b0 + b1 * c_max + b2 * c_max * c_max;
 
   // again cut out explicitly regions of zero flux 
   double c_cut = -0.42 + L*0.35;
   if (c_cut > cmax) c_cut = cmax; 
   
   // now we throw dice:
   
   while (1)
     {
       prob = RanGen2->flat();
       r1 = double(prob);
       prob = RanGen2->flat();
       r2 = double(prob);
       c = cmin + (c_cut-cmin)*r1;    
       z = b0 + b1 * c + b2 * c*c;
       if (z > z_max*r2) break;
     }    
   
   return 0;
   
 }

int CMSCGEN::generateNuMu ( )

Definition at line 588 of file CMSCGEN.cc.

References c, cmax, cmin, gather_cfg::cout, dNdEmudEnu(), dNdEmudEnuMax, enumax, enumin, initialization, pmax, pmin, pq, RanGen2, scaleCards::rate, and Rnunubar.

Referenced by CosmicMuonGenerator::nextEvent().

                           {
   if(initialization==0) 
     {
       std::cout << " >>> CMSCGEN <<< warning: not initialized" << std::endl;
       return -1;
     }
   
   double ctheta, Emu;
   while (1) {
     ctheta = cmin + (cmax-cmin)*RanGen2->flat();
     Emu = pmin + (pmax-pmin)*RanGen2->flat();
     double Enu = enumin + (enumax-enumin)*RanGen2->flat();
     double rate = dNdEmudEnu(Enu, Emu, ctheta);
     if (rate > dNdEmudEnuMax*RanGen2->flat()) break;
   }
 
   c = -ctheta; //historical sign convention
 
   pq = Emu;
   //
   // +++ nu/nubar ratio (~1.2)
   //
   double charg = 1.; //nubar -> mu+
   if (RanGen2->flat() > Rnunubar/(1.+Rnunubar))
     charg = -1.; //neutrino -> mu-
 
   pq = pq*charg;
  
   
   //int flux += this event rate
 
   return 1;
 }

int CMSCGEN::initialize	(	double	pmin_in,
		double	pmax_in,
		double	thetamin_in,
		double	thetamax_in,
		CLHEP::HepRandomEngine *	rnd,
		bool	TIFOnly_constant,
		bool	TIFOnly_linear
	)

Definition at line 23 of file CMSCGEN.cc.

References b0, b0c, b1, b1c, b2, b2c, c1, c2, cemax, cmax, cmax_in, cmax_max, cmax_min, cmin, cmin_in, corr, gather_cfg::cout, delRanGen, initialization, integrated_flux, gen::k, dttmaxenums::L, Lfac, Lmax, Lmin, AlCaHLTBitMon_ParallelJobs::p, p1, p2, pe, pmax, pmin, pmin_max, pmin_min, funct::pow(), RanGen2, alignCSCRings::s, TIFOnly_const, TIFOnly_lin, xemax, and xemin.

Referenced by initialize(), and CosmicMuonGenerator::initialize().

 {
   if (delRanGen)
     delete RanGen2;
   RanGen2 = rnd;
   delRanGen = false;
 
   //set bools for TIFOnly options (E<2GeV with unphysical energy dependence)
   TIFOnly_const = TIFOnly_constant;
   TIFOnly_lin = TIFOnly_linear;
 
 
   // units: GeV
 
   // WARNING: coordinate system: 
   //   - to outside world define z axis downwards, i.e.
   //          muon coming from above, vertically: cos = 1
   //      (used for backward compatibility)
   //   - internally use frame with z axis upwards, i.e.
   //          muon coming from above, vertically: cos = -1
   //     (corresponds to CMS note definition)
 
   //set cmin and cmax, here convert between coordinate systems:
   cmin_in = - TMath::Cos(thetamin_in);//input angle already converted from Deg to Rad!
   cmax_in = - TMath::Cos(thetamax_in);//input angle already converted from Deg to Rad!
 
 
   //allowed energy range
   pmin_min = 3.;
   //pmin_max = 100.;
   pmin_max = 3000.;
   pmax = 3000.;
   //allowed angular range
   //cmax_max = -0.1,
   cmax_max = -0.01,
   cmax_min = -0.9999;
 
  if(TIFOnly_const == true || TIFOnly_lin == true) pmin_min = 0.; //forTIF
 
   // set pmin  
   if(pmin_in < pmin_min || pmin_in > pmin_max){ 
     std::cout << " >>> CMSCGEN.initialize <<< warning: illegal pmin_in =" << pmin_in;
     return(-1);
   } else if(pmax_in > pmax ){
     std::cout << " >>> CMSCGEN.initialize <<< warning: illegal pmax_in =" << pmax_in;
     return(-1);
   }else{     
     pmin = pmin_in;
     pmax = pmax_in;
     xemax = 1./(pmin*pmin);
     xemin = 1./(pmax*pmax); 
   }
 
 
   // set cmax and cmin
   if(cmax_in < cmax_min || cmax_in > cmax_max)
     { 
       std::cout << " >>> CMSCGEN.initialize <<< warning: illegal cmax_in =" << cmax_in;
       return(-1);
     }
   else 
     {
       cmax = cmax_in;
       cmin = cmin_in;
     }
 
 
   initialization = 1;
 
   if(TIFOnly_const == true || TIFOnly_lin == true) pmin_min = 3.; //forTIF
 
   //  Lmin = log10(pmin_min);
   Lmin = log10(pmin);
   Lmax = log10(pmax);
   Lfac = 100./(Lmax-Lmin);
 
   //
   // +++ coefficients for energy spectrum
   //
 
   pe[0] = -1.;
   pe[1] = 6.22176;
   pe[2] = -13.9404;
   pe[3] = 18.1643;
   pe[4] = -9.22784;
   pe[5] = 1.99234;
   pe[6] = -0.156434;
   pe[7] = 0.;
   pe[8] = 0.;
 
   //
   // +++ coefficients for cos theta distribution
   //
 
   b0c[0] = 0.6639;
   b0c[1] = -0.9587;
   b0c[2] = 0.2772;
   
   b1c[0] = 5.820;
   b1c[1] = -6.864;
   b1c[2] = 1.367;
   
   b2c[0] = 10.39;
   b2c[1] = -8.593;
   b2c[2] = 1.547;
   
   //
   // +++ calculate correction table for different cos theta dependence!
   //     reference range: c1  to  c2 
   //
   //  explanation: the parametrization of the energy spectrum as used above
   //    is the integral over the c = cos(zenith angle) range -1...-0.1 
   //    since the c distribution depends on energy, the integrated energy
   //    spectrum depends on this range. Here a correction factor is determined,
   //    based on the linear c dependence of the c distribution.
   //    The correction is calculated for 100 bins in L = log10(energy).
   //
   // +++ in same loop calculate integrated flux 
   //      (integrated over angles and momentum)
 
   c1 = -1.;
   c2 = -0.1;
   
   double cemax0 = 1.0;
   double L, L2; 
   double s;
   double p, p1, p2;
   double integral_here, integral_ref;
   double c_cut;
 
   integrated_flux = 0.;
   
   for(int k=1; k<=100; k++)
     {
       L = Lmin + (k-0.5)/Lfac;
       L2 = L*L;   
       p = pow(10,L);
       p1 = pow(10,L-0.5/Lfac);
       p2 = pow(10,L+0.5/Lfac);
       
       b0 = b0c[0] + b0c[1] * L + b0c[2]* L2;
       b1 = b1c[0] + b1c[1] * L + b1c[2]* L2;
       b2 = b2c[0] + b2c[1] * L + b2c[2]* L2;
 
       // cut out explicitly regions of zero flux 
       // (for low momentum and near horizontal showers)
       // since parametrization for z distribution doesn't work here
       // (can become negative) 
       
       c_cut = -0.42 + L*0.35;
       
       if (c_cut > c2) c_cut = c2; 
       
       integral_ref = b0 * (c_cut - c1) 
     + b1/2. * (c_cut*c_cut - c1*c1) 
     + b2/3. * (c_cut*c_cut*c_cut - c1*c1*c1);
       
       if (c_cut > cmax) c_cut = cmax; 
       
       integral_here = b0 * (c_cut - cmin) 
     + b1/2. * (c_cut*c_cut - cmin*cmin) 
     + b2/3. * (c_cut*c_cut*c_cut - cmin*cmin*cmin);
   
       corr[k] = integral_here/integral_ref;
       
       s = (((((((pe[8]*L
          +pe[7])*L
         +pe[6])*L
            +pe[5])*L
           +pe[4])*L
          +pe[3])*L
         +pe[2])*L
        +pe[1])*L
     +pe[0];
     
       integrated_flux += 1./pow(p,3) * s * corr[k] * (p2-p1);
 
       /*
     std::cout << k << " " 
     << corr[k] << " " 
     << p << " " 
     << s << " " 
     << p1 << " " 
     << p2 << " " 
     << integrated_flux << " " 
     << std::endl;
       */
       
       // std::cout << k << " " << corr[k] << " " << std::endl;
     }
 
   integrated_flux *= 1.27E3;
   std::cout << " >>> CMSCGEN.initialize <<< " <<
     " Integrated flux = " << integrated_flux << " /m**2/s " << std::endl;
   
   //  find approximate peak value, for Monte Carlo sampling
   //      peak is near L = 2 
 
   double ce;
   
   ce = (((((((pe[8]*2.
           +pe[7])*2.
          +pe[6])*2.
             +pe[5])*2.
        +pe[4])*2.
       +pe[3])*2.
      +pe[2])*2.
     +pe[1])*2.
     +pe[0];
 
   // normalize to 0.5 (not 1) to have some margin if peak is not at L=2
   //
   ce = 0.5/ce;
 
   for (int k=0; k<9; k++)
     {
       pe[k] = pe[k]*ce;
     }
 
   cemax = cemax0*corr[50];      
 
   return initialization;
 }

int CMSCGEN::initialize	(	double	pmin_in,
		double	pmax_in,
		double	thetamin_in,
		double	thetamax_in,
		int	RanSeed,
		bool	TIFOnly_constant,
		bool	TIFOnly_linear
	)

Definition at line 247 of file CMSCGEN.cc.

References delRanGen, and initialize().

 {
   CLHEP::HepRandomEngine *rnd = new CLHEP::HepJamesRandom;
   //set seed for Random Generator (seed can be controled by config-file), P.Biallass 2006
   rnd->setSeed(RanSeed, 0);
   delRanGen = true;
   return initialize(pmin_in, pmax_in, thetamin_in, thetamax_in, rnd, TIFOnly_constant, TIFOnly_linear);
 }

int CMSCGEN::initializeNuMu	(	double	pmin_in,
		double	pmax_in,
		double	thetamin_in,
		double	thetamax_in,
		double	Enumin_in,
		double	Enumax_in,
		double	Phimin_in,
		double	Phimax_in,
		double	ProdAlt_in,
		CLHEP::HepRandomEngine *	rnd
	)

Definition at line 495 of file CMSCGEN.cc.

References AR, cmax, cmin, gather_cfg::cout, delRanGen, dNdEmudEnu(), dNdEmudEnuMax, alignCSCRings::e, enumax, enumin, i, initialization, integrated_flux, negabs, negfrac, pmax, pmin, ProdAlt, RanGen2, scaleCards::rate, Rnunubar, and sigma.

Referenced by CosmicMuonGenerator::initialize(), and initializeNuMu().

 {
   if (delRanGen)
     delete RanGen2;
   RanGen2 = rnd;
   delRanGen = false;
 
   ProdAlt = ProdAlt_in;
 
   Rnunubar = 1.2;
 
   sigma = (0.72*Rnunubar+0.09)/(1+Rnunubar)*1.e-38; //cm^2GeV^-1
 
   AR = (0.69+0.06*Rnunubar)/(0.09+0.72*Rnunubar);
 
 
   //set smin and smax, here convert between coordinate systems:
   pmin = pmin_in;
   pmax = pmax_in;
   cmin = TMath::Cos(thetamin_in);//input angle already converted from Deg to Rad!
   cmax = TMath::Cos(thetamax_in);//input angle already converted from Deg to Rad!
   enumin = (Enumin_in < 10.) ? 10. : Enumin_in; //no nu's below 10GeV
   enumax = Enumax_in;
 
 
   //do initial run of flux rate to determine Maximum
   integrated_flux = 0.;
   dNdEmudEnuMax = 0.;
   negabs = 0.;
   negfrac = 0.;
   int trials = 100000;
   for (int i=0; i<trials; ++i) {
     double ctheta = cmin + (cmax-cmin)*RanGen2->flat();
     double Emu = pmin + (pmax-pmin)*RanGen2->flat();
     double Enu = enumin + (enumax-enumin)*RanGen2->flat();
     double rate =  dNdEmudEnu(Enu, Emu, ctheta);
     //std::cout << "trial=" << i << " ctheta=" << ctheta << " Emu=" << Emu << " Enu=" << Enu 
     //      << " rate=" << rate << std::endl;
     //std::cout << "cmin=" << cmin << " cmax=" << cmax 
     //      << " pmin=" << pmin << " pmax=" << pmax 
     //      << " enumin=" << enumin << " enumax=" << enumax << std::endl;
     if (rate > 0.) {
       integrated_flux += rate;
       if (rate > dNdEmudEnuMax)
     dNdEmudEnuMax = rate;
     }
     else negabs++;
   }
   negfrac = negabs/trials;
   integrated_flux /= trials;
 
   std::cout << "CMSCGEN::initializeNuMu: After " << trials << " trials:" << std::endl;
   std::cout << "dNdEmudEnuMax=" << dNdEmudEnuMax << std::endl;
   std::cout << "negfrac=" << negfrac << std::endl;
 
   //multiply by phase space boundaries
   integrated_flux *= (cmin-cmax);
   integrated_flux *= (Phimax_in-Phimin_in);
   integrated_flux *= (pmax-pmin);
   integrated_flux *= (enumax-enumin);
   //remove negative phase space areas which do not contribute anything
   integrated_flux *= (1.-negfrac);
   std::cout << " >>> CMSCGEN.initializeNuMu <<< " <<
     " Integrated flux = " << integrated_flux << " units??? " << std::endl;
 
 
   initialization = 1;
 
   return initialization;
 
 } 

int CMSCGEN::initializeNuMu	(	double	pmin_in,
		double	pmax_in,
		double	thetamin_in,
		double	thetamax_in,
		double	Enumin_in,
		double	Enumax_in,
		double	Phimin_in,
		double	Phimax_in,
		double	ProdAlt_in,
		int	RanSeed
	)

Definition at line 567 of file CMSCGEN.cc.

References delRanGen, and initializeNuMu().

 {
   CLHEP::HepRandomEngine *rnd = new CLHEP::HepJamesRandom;
   //set seed for Random Generator (seed can be controled by config-file), P.Biallass 2006
   rnd->setSeed(RanSeed, 0);
   delRanGen = true;
   return initializeNuMu(pmin_in, pmax_in, thetamin_in, thetamax_in, Enumin_in, Enumax_in, Phimin_in, Phimax_in, ProdAlt_in, rnd);
 }

double CMSCGEN::momentum_times_charge ( )

Definition at line 447 of file CMSCGEN.cc.

References gather_cfg::cout, initialization, and pq.

Referenced by CosmicMuonGenerator::nextEvent().

 {
   
   if(initialization==1)
     { 
       return pq;
     }
   else
     {
       std::cout << " >>> CMSCGEN <<< warning: not initialized" << std::endl;
       return -9999.;
     }
 
 }