LauBelleNR.cc

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// Copyright University of Warwick 2004 - 2013.
// 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 "LauBelleNR.hh"
#include "LauDaughters.hh"

ClassImp(LauBelleNR)


LauBelleNR::LauBelleNR(const TString& resName, const LauAbsResonance::LauResonanceModel resType,
                       const Double_t resMass, const Double_t resWidth, const Int_t resSpin,
                       const Int_t resCharge, const Int_t resPairAmpInt, const LauDaughters* daughters) :
        LauAbsResonance(resName, resMass, resWidth, resSpin, resCharge, resPairAmpInt, daughters),
        alpha_(0.0),
        model_(resType)
{
}

LauBelleNR::~LauBelleNR()
{
}

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

        if ( model_ != LauAbsResonance::BelleNR && model_ != LauAbsResonance::PowerLawNR ) {
                std::cerr << "WARNING in LauBelleNR::initialise : Unknown model requested, defaulting to exponential." << std::endl;
                model_ = LauAbsResonance::BelleNR;
        }

        // TODO - should the BelleNR ignore the momenta in the spin term?
}

LauComplex LauBelleNR::resAmp(Double_t mass, Double_t spinTerm)
{
        Double_t magnitude(1.0);

        if ( model_ == LauAbsResonance::BelleNR ) {
                magnitude = spinTerm * TMath::Exp(-alpha_*mass*mass);
        } else if ( model_ == LauAbsResonance::PowerLawNR ) {
                magnitude = spinTerm * TMath::Power(mass*mass, -alpha_);
        }

        LauComplex resAmplitude(magnitude, 0.0);

        return resAmplitude;
}

void LauBelleNR::setResonanceParameter(const TString& name, const Double_t value) 
{
        // Set various parameters for the lineshape
        if (name == "alpha") {
                this->setAlpha(value);
                std::cout << "INFO in LauBelleNR::setResonanceParameter : Setting parameter alpha = " << this->getAlpha() << std::endl;
        } else {
                std::cerr << "WARNING in LauBelleNR::setResonanceParameter: Parameter name not reconised.  No parameter changes made." << std::endl;
        }
}