nPDF Class Reference

A derived class for nuclear PDFs. Needs a pointer for (free) proton PDFs. More...

#include <PartonDistributions.h>

Inheritance diagram for nPDF:

Public Member Functions
	nPDF (int idBeamIn=2212, PDFPtr protonPDFPtrIn=0)
	Constructor.
void	xfUpdate (int id, double x, double Q2) override
	Update parton densities. More...
virtual void	rUpdate (int, double, double)=0
	Update nuclear modifications.
void	initNPDF (int idBeamIn, PDFPtr protonPDFPtrIn=0)
	Initialize the nPDF-related members. More...
int	getA ()
	Return the number of protons and nucleons.
int	getZ ()
void	setMode (double zaIn)
void	resetMode ()
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 double	xGamma ()
	Return the sampled value for x_gamma.
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	sampleQ2gamma (double)
virtual double	fluxQ2dependence (double)
virtual double	xfMax (int id, double x, double Q2)
	Normal PDFs unless gamma inside lepton -> an overestimate for sampling.
virtual double	xfSame (int id, double x, double Q2)
	Normal PDFs unless gamma inside lepton -> Do not sample x_gamma.
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)

Protected Attributes
double	ruv
double	rdv
double	ru
double	rd
double	rs
double	rc
double	rb
double	rg
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

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.

Detailed Description

A derived class for nuclear PDFs. Needs a pointer for (free) proton PDFs.

Member Function Documentation

void initNPDF	(	int	idBeamIn,
		PDFPtr	protonPDFPtrIn = 0
	)

Initialize the nPDF-related members.

Inherited class for nuclear PDFs. Needs a proton PDF as a baseline.

Derive mass number and number of protons.

Normalized number of protons and neutrons in nuclei.

Initialize proton PDF pointer.

No modifications yet.

void setMode ( double  zaIn )

inline

Set (and reset) the ratio of protons to nucleons to study nuclear modifications of protons (= 1.0) and neutrons (= 0.0). By default Z/A.

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

overridevirtual

Update parton densities.

Updates the nPDF using provided proton PDF and nuclear modification.

Update the proton PDFs and nuclear modifications.

u(bar) and d(bar) pdfs for proton.

Neutron nPDFs using isospin symmetry.

idSav = 9 to indicate that all flavours reset.

Implements PDF.

Member Data Documentation

double ruv

protected

The nuclear modifications for each flavour, modified by derived nPDF classes.

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

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