#include <PartonDistributions.h>

Inheritance diagram for Lepton2gamma:

Public Member Functions
	Lepton2gamma (int idBeamIn, double m2leptonIn, double Q2maxGamma, PDFPtr gammaPDFPtrIn, Info *infoPtrIn)
	Constructor.

void	xfUpdate (int id, double x, double Q2) override
	Overload the member function definitions where relevant. More...

double	xGamma () override
	Return the sampled value for x_gamma.

double	xfMax (int id, double x, double Q2) override

double	xfSame (int id, double x, double Q2) override

double	sampleQ2gamma (double Q2min) override
	Sample the Q2 value.

Public Member Functions inherited from PDF
	PDF (int idBeamIn=2212)
	Constructor.

virtual	~PDF ()
	Virtual destructor.

virtual bool	init (int, string, int, Logger *)

bool	isSetup ()
	Confirm that PDF has been set up (important for LHAPDF and H1 Pomeron).

virtual void	setBeamID (int idBeamIn)
	Switch to new beam particle identities; for similar hadrons only.

void	resetValenceContent ()
	Set valence content. More...

void	setValenceContent (int idVal1In, int idVal2In, int idVal3In)

virtual void	setExtrapolate (bool)
	Allow extrapolation beyond boundaries. This is optional.

double	xf (int id, double x, double Q2)
	Read out parton density. More...

double	xfVal (int id, double x, double Q2)
	Read out valence and sea part of parton densities. More...

double	xfSea (int id, double x, double Q2)
	Only sea part of parton densities. More...

virtual bool	insideBounds (double, double)
	Check whether x and Q2 values fall inside the fit bounds (LHAPDF6 only).

virtual double	alphaS (double)
	Access the running alpha_s of a PDF set (LHAPDF6 only).

virtual double	mQuarkPDF (int)
	Return quark masses used in the PDF fit (LHAPDF6 only).

virtual int	nMembers ()
	Return number of members of this PDF family (LHAPDF6 only).

virtual void	calcPDFEnvelope (int, double, double, int)
	Calculate PDF envelope.

virtual void	calcPDFEnvelope (pair< int, int >, pair< double, double >, double, int)

virtual PDFEnvelope	getPDFEnvelope ()

virtual double	gammaPDFxDependence (int, double)
	Approximate photon PDFs by decoupling the scale and x-dependence.

virtual double	gammaPDFRefScale (int)
	Provide the reference scale for logarithmic Q^2 evolution for photons.

virtual int	sampleGammaValFlavor (double)
	Sample the valence content for photons.

virtual double	xfIntegratedTotal (double)
	The total x-integrated PDFs. Relevant for MPIs with photon beams.

virtual void	xPom (double=-1.0)
	Keep track of pomeron momentum fraction.

virtual double	xfFlux (int, double, double)
	Return accurate and approximated photon fluxes and PDFs.

virtual double	xfApprox (int, double, double)

virtual double	xfGamma (int, double, double)

virtual double	intFluxApprox ()

virtual bool	hasApproxGammaFlux ()

virtual double	getXmin ()
	Return the kinematical limits and sample Q2 and x.

virtual double	getXhadr ()

virtual double	sampleXgamma (double)

virtual double	fluxQ2dependence (double)

virtual void	setVMDscale (double=1.)
	Allow for new scaling factor for VMD PDFs.

bool	sSymmetric () const
	Return if s/sbar, c/cbar, and b/bbar PDFs are symmetric.

bool	cSymmetric () const

bool	bSymmetric () const

void	sSymmetric (bool sSymmetricIn)
	Set s/sbar, c/cbar, and b/bbar PDFs symmetric.

void	cSymmetric (bool cSymmetricIn)

void	bSymmetric (bool bSymmetricIn)

Additional Inherited Members
Protected Member Functions inherited from PDF
void	printErr (string loc, string errMsg, Logger *loggerPtr=nullptr)
	Small routine for error printout, depending on loggerPtr existing or not.

double	xfRaw (int id) const
	Get the raw stored value for the quark variable corresponding to the id. More...

bool	isValence (int id) const
	Check whether the specified id is a valence quark.

Protected Attributes inherited from PDF
int	idBeam
	Store relevant quantities.

int	idBeamAbs

int	idSav

int	idVal1

int	idVal2

int	idVal3

double	xSav

double	Q2Sav

double	xu
	Stored quantities.

double	xd

double	xs

double	xubar

double	xdbar

double	xsbar

double	xc

double	xb

double	xcbar

double	xbbar

double	xg

double	xlepton

double	xgamma

bool	isSet

bool	isInit

int	beamType

bool	hasGammaInLepton
	True if a photon beam inside a lepton beam, otherwise set false.

bool	sSymmetricSave = false
	Whether to treat flavoured PDFs as symmetric, for efficiency.

bool	cSymmetricSave = true

bool	bSymmetricSave = true

Detailed Description

Convolution with photon flux from leptons and photon PDFs. Photon flux from equivalent photon approximation (EPA). Contains a pointer to a photon PDF set and samples the convolution integral event-by-event basis. Includes also a overestimate for the PDF set in order to set up the phase-space sampling correctly.

Member Function Documentation

double xfMax	(	int	id,
		double	x,
		double	Q2
	)

overridevirtual

Approximate the maximum of convoluted PDF to correctly set up the sampling of the phase space.

Find the maximum x value at given Q2max and sqrt(s).

Set PDFs to zero outside allowed x values.

Pre-calculate some logs.

Find approximate x-behaviour for each flavour. Optimized for CJKL.

Direct photons in usual lepton PDFs.

Return the approximation.

Reimplemented from PDF.

double xfSame	(	int	id,
		double	x,
		double	Q2
	)

overridevirtual

Return PDF without sampling x_gamma values to compute cross section with rescaled sHat. Not very elegant but no need to modify the xfUpdate call.

Reimplemented from PDF.

void xfUpdate	(	int	id,
		double	x,
		double	Q2
	)

overridevirtual

Overload the member function definitions where relevant.

Update PDFs and sample a value for x_gamma.

Find the maximum x value at given Q2max and sqrt(s).

If outside allowed x values set PDFs to zero.

Pre-calculate some logs.

Sample x_gamma.

Evaluate the PDFs at x/x_gamma.

Calculate the Q^2_min for sampled x_gamma.

Correct with weight.

Calculate the PDF value.

Photon inside electron not currently implemented (Use point-like lepton).

idSav = 9 to indicate that all flavours reset.

Implements PDF.

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

include/Pythia8/PartonDistributions.h
src/PartonDistributions.cc

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation