Public Member Functions
	__init__ (self, mass, eps)

	readPDGtable (self)

	interpolatePDGtable (self)

	Ree_interp (self, s)

	leptonicDecayWidth (self, lepton)

	leptonicBranchingRatio (self, lepton)

	hadronicDecayWidth (self)

	hadronicBranchingRatio (self)

	totalDecayWidth (self)

	cTau (self)

	lifetime (self)

	findBranchingRatio (self, decayString)

	allowedChannels (self)

	scaleNEventsIncludingHadrons (self, n)

Public Attributes
	mDarkPhoton

	epsilon

	dataEcm

	dataR

	PdgR

Detailed Description

Definition at line 20 of file darkphoton.py.

Constructor & Destructor Documentation

◆ init()

darkphoton.DarkPhoton.__init__	(	self,
		mass,
		eps
	)

Definition at line 23 of file darkphoton.py.

    def __init__(self, mass, eps):
        self.mDarkPhoton = mass
        self.epsilon = eps
        self.dataEcm,self.dataR = self.readPDGtable()
        self.PdgR = self.interpolatePDGtable()
 

Member Function Documentation

◆ allowedChannels()

darkphoton.DarkPhoton.allowedChannels ( self )

Definition at line 141 of file darkphoton.py.

    def allowedChannels(self):
        print("Allowed channels for dark photon mass = %3.3f"%self.mDarkPhoton)
        allowedDecays = {'A -> hadrons':'yes'}
        if self.mDarkPhoton > 2.*mass('e-'):
            allowedDecays.update({'A -> e- e+':'yes'})
            print("allowing decay to e")
        if self.mDarkPhoton > 2.*mass('mu-'):
            allowedDecays.update({'A -> mu- mu+':'yes'})
            print("allowing decay to mu")
        if self.mDarkPhoton > 2.*mass('tau-'):
            allowedDecays.update({'A -> tau- tau+':'yes'})
            print("allowing decay to tau")
                        
        return allowedDecays
                    
                            

◆ cTau()

darkphoton.DarkPhoton.cTau ( self )

 Dark Photon lifetime in cm

Definition at line 120 of file darkphoton.py.

    def cTau(self): # decay length in meters, dark photon mass in GeV
        """ Dark Photon lifetime in cm"""
        ctau=hGeV*ccm/self.totalDecayWidth()
        #print "ctau dp.py %.3e"%(ctau) 
        return ctau #GeV/MeV conversion
    

◆ findBranchingRatio()

darkphoton.DarkPhoton.findBranchingRatio	(	self,
		decayString
	)

Definition at line 129 of file darkphoton.py.

    def findBranchingRatio(self,decayString):
        br = 0.
        if   decayString == 'A -> e- e+': br = self.leptonicBranchingRatio('e-')
        elif   decayString == 'A -> mu- mu+': br = self.leptonicBranchingRatio('mu-')
        elif   decayString == 'A -> tau- tau+': br = self.leptonicBranchingRatio('tau-')
        elif   decayString == 'A -> hadrons': br = self.hadronicBranchingRatio()
        else:
            print('findBranchingRatio ERROR: unknown decay %s'%decayString)
            quit()
            
        return br
 

◆ hadronicBranchingRatio()

darkphoton.DarkPhoton.hadronicBranchingRatio ( self )

Definition at line 105 of file darkphoton.py.

    def hadronicBranchingRatio(self):
        return self.hadronicDecayWidth() / self.totalDecayWidth()
    

◆ hadronicDecayWidth()

darkphoton.DarkPhoton.hadronicDecayWidth ( self )

 Dark photon decay into hadrons

(mumu)*R

Definition at line 97 of file darkphoton.py.

    def hadronicDecayWidth(self):
        """ Dark photon decay into hadrons """
        """(mumu)*R"""
        gmumu=self.leptonicDecayWidth('mu-')
        tdw=gmumu*self.Ree_interp(self.mDarkPhoton)
        #print 'Hadronic decay width is %.3e'%(tdw)
        return tdw;
    

◆ interpolatePDGtable()

darkphoton.DarkPhoton.interpolatePDGtable ( self )

 Find the best value for R for the given center-of-mass energy

Definition at line 57 of file darkphoton.py.

    def interpolatePDGtable(self):
        """ Find the best value for R for the given center-of-mass energy """
        fun = r.Math.Interpolator(self.dataEcm.size(),r.Math.Interpolation.kLINEAR)
        fun.SetData(self.dataEcm,self.dataR);
        return fun
 

◆ leptonicBranchingRatio()

darkphoton.DarkPhoton.leptonicBranchingRatio	(	self,
		lepton
	)

Definition at line 94 of file darkphoton.py.

    def leptonicBranchingRatio(self,lepton):
        return self.leptonicDecayWidth(lepton) / self.totalDecayWidth()
        

◆ leptonicDecayWidth()

darkphoton.DarkPhoton.leptonicDecayWidth	(	self,
		lepton
	)

 Dark photon decay width into leptons, in GeV (input short name of lepton family)

Definition at line 78 of file darkphoton.py.

    def leptonicDecayWidth(self,lepton): # mDarkPhoton in GeV
        """ Dark photon decay width into leptons, in GeV (input short name of lepton family) """
        ml = mass(lepton)
        #print 'lepton %s mass %.3e'%(lepton,ml)
        
        constant = (1./3.) * alphaQED * self.mDarkPhoton * pow(self.epsilon, 2.)
        if 2.*ml < self.mDarkPhoton:
            rad = math.sqrt( 1. - (4.*ml*ml)/(self.mDarkPhoton*self.mDarkPhoton) )
        else:
            rad = 0.
            
        par = 1. + (2.*ml*ml)/(self.mDarkPhoton*self.mDarkPhoton)
        tdw=math.fabs(constant*rad*par)
        #print 'Leptonic decay width to %s is %.3e'%(lepton,tdw)
        return tdw
    

◆ lifetime()

darkphoton.DarkPhoton.lifetime ( self )

Definition at line 126 of file darkphoton.py.

    def lifetime(self):
        return self.cTau()/ccm
 

◆ readPDGtable()

darkphoton.DarkPhoton.readPDGtable ( self )

 Returns R data from PDG in a easy to use format

Definition at line 29 of file darkphoton.py.

    def readPDGtable(self):
        """ Returns R data from PDG in a easy to use format """
        ecm=r.vector('double')()
        ratio=r.vector('double')()
        """ecm,ratio = [],[]"""
        with open(os.path.expandvars('$FAIRSHIP/input/rpp2012-hadronicrpp_page1001.dat'),'r') as f:
            for line in f:
                line = line.split()
                try:
                    numEcm = float(line[0])
                    numR = float(line[3])
                    strType = line[7]
                    strBis = line[8]
                    #if numEcm<2:
                    #   print numEcm,numR,strType
                    if (('EXCLSUM' in strType) or ('EDWARDS' in strType) or ('BLINOV' in strType)):
                        ecm.push_back(numEcm)
                        ratio.push_back(numR)
                        #print numEcm,numR,strType
                    if 'BAI' in strType and '01' in strBis:
                        ecm.push_back(numEcm)
                        ratio.push_back(numR)
                        #print numEcm,numR,strType
                except:
                    continue
        return ecm,ratio
 
 

◆ Ree_interp()

darkphoton.DarkPhoton.Ree_interp	(	self,
		s
	)

 Using PDG values for sigma(e+e- -> hadrons) / sigma(e+e- -> mu+mu-)

Definition at line 63 of file darkphoton.py.

    def Ree_interp(self,s): # s in GeV
        """ Using PDG values for sigma(e+e- -> hadrons) / sigma(e+e- -> mu+mu-) """
        # Da http://pdg.lbl.gov/2012/hadronic-xsections/hadron.html#miscplots
        #ecm = math.sqrt(s)
        ecm = s
        if ecm>=10.29:
            print('Warning! Asking for interpolation beyond 10.29 GeV: not implemented, needs extending! Taking value at 10.29 GeV')
            result=float(self.PdgR.Eval(10.29))
        elif ecm>=self.dataEcm[0]:
            result = float(self.PdgR.Eval(ecm))
        else:
            result=0
        #print 'Ree_interp for mass %3.3f is %.3e'%(s,result)
        return result
 

◆ scaleNEventsIncludingHadrons()

darkphoton.DarkPhoton.scaleNEventsIncludingHadrons	(	self,
		n
	)

 Very simple patch to take into account A' -> hadrons

Definition at line 157 of file darkphoton.py.

    def scaleNEventsIncludingHadrons(self,n):
        """ Very simple patch to take into account A' -> hadrons """
        brh = self.hadronicBranchingRatio()
        #print brh
        # if M > m(c cbar):
        if self.mDarkPhoton > 2.*mass('c'):
            visible_frac = 1.
        else:
            visible_frac = 2./3.
    
        increase = brh*visible_frac
        #print increase
        return n*(1. + increase)
            
            

◆ totalDecayWidth()

darkphoton.DarkPhoton.totalDecayWidth ( self )

 Total decay width in GeV

Definition at line 108 of file darkphoton.py.

    def totalDecayWidth(self): # mDarkPhoton in GeV
        """ Total decay width in GeV """
        #return hGeV*c / cTau(mDarkPhoton, epsilon)
        tdw = (self.leptonicDecayWidth('e-')
               + self.leptonicDecayWidth('mu-')
               + self.leptonicDecayWidth('tau-')
               + self.hadronicDecayWidth())
        
        #print 'Total decay width %e'%(tdw)
        
        return tdw
 

Member Data Documentation

◆ dataEcm

darkphoton.DarkPhoton.dataEcm

Definition at line 26 of file darkphoton.py.

◆ dataR

darkphoton.DarkPhoton.dataR

Definition at line 26 of file darkphoton.py.

◆ epsilon

darkphoton.DarkPhoton.epsilon

Definition at line 25 of file darkphoton.py.

◆ mDarkPhoton

darkphoton.DarkPhoton.mDarkPhoton

Definition at line 24 of file darkphoton.py.

◆ PdgR

darkphoton.DarkPhoton.PdgR

Definition at line 27 of file darkphoton.py.

The documentation for this class was generated from the following file:

python/darkphoton.py

Public Member Functions

Public Attributes