LauPolNR.cc

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// Copyright University of Warwick 2004 - 2014.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

// Authors:
// Thomas Latham
// John Back
// Paul Harrison

#include <iostream>

#include "TMath.h"

#include "LauPolNR.hh"
#include "LauDaughters.hh"

ClassImp(LauPolNR)


LauPolNR::LauPolNR(LauResonanceInfo* resInfo, const Int_t resPairAmpInt, const LauDaughters* daughters) :
        LauAbsResonance(resInfo, resPairAmpInt, daughters),
        omega_(0.0),
        order_(0)
{
}

LauPolNR::~LauPolNR()
{
}

void LauPolNR::initialise()
{
        const LauDaughters* daughters = this->getDaughters();
        Int_t resPairAmpInt = this->getPairInt();
        if ( daughters->gotSymmetricalDP() && resPairAmpInt != 3 ) {
                std::cerr << "WARNING in LauPolNR::initialise : Dalitz plot is symmetric - this lineshape is not appropriate." << std::endl;
        }

        // Make the spin term purely the Legendre polynomial of the cos(helicity angle)
        this->setSpinType( LauAbsResonance::Legendre );

        Double_t omega = 0.5*(daughters->getMassParent()+(1.0/3.0)*(daughters->getMassDaug1()+daughters->getMassDaug2()+daughters->getMassDaug3()));
        this->setOmega( omega );

        TString name = this->getResonanceName();
        if (name.EndsWith("0",TString::kExact)){
                order_ = 0;
        }
        else if (name.EndsWith("1",TString::kExact)){
                order_ = 1;
        }
        else if (name.EndsWith("2",TString::kExact)){
                order_ = 2;
        }
        else if (name.EndsWith("3",TString::kExact)){
                order_ = 3;
        }
        else{
                std::cerr << "ERROR in LauPolNR::initialise : Resonance order unknown (known orders : 0, 1, 2 and 3)" << std::endl;
                std::cerr << "                              : Defaulting to 0." << std::endl;
        }
}

LauComplex LauPolNR::resAmp(Double_t mass, Double_t spinTerm)
{
        Double_t magnitude( spinTerm );

        Double_t massDiff = mass - omega_;
        for ( UInt_t i(0); i < order_; ++i ) {
                magnitude *= massDiff;
        }

        LauComplex resAmplitude(magnitude, 0.0);

        return resAmplitude;
}