PYTHIA  8.303
Public Member Functions | List of all members
Lepton2gamma Class Reference

#include <PartonDistributions.h>

Inheritance diagram for Lepton2gamma:
PDF

Public Member Functions

 Lepton2gamma (int idBeamIn, double m2leptonIn, double Q2maxGamma, PDFPtr gammaPDFPtrIn, Info *infoPtrIn)
 Constructor.
 
void xfUpdate (int id, double x, double Q2)
 Overload the member function definitions where relevant. More...
 
double xGamma ()
 Return the sampled value for x_gamma.
 
double xfMax (int id, double x, double Q2)
 
double xfSame (int id, double x, double Q2)
 
double sampleQ2gamma (double Q2min)
 Sample the Q2 value.
 
- Public Member Functions inherited from PDF
 PDF (int idBeamIn=2212)
 Constructor.
 
virtual ~PDF ()
 Destructor.
 
virtual bool isSetup ()
 Confirm that PDF has been set up (important for LHAPDF and H1 Pomeron).
 
virtual void newValenceContent (int idVal1In, int idVal2In)
 Dynamic choice of meson valence flavours for pi0, K0S, K0L, Pomeron.
 
virtual void setExtrapolate (bool)
 Allow extrapolation beyond boundaries. This is optional.
 
virtual double xf (int id, double x, double Q2)
 Read out parton density. More...
 
virtual double xfVal (int id, double x, double Q2)
 Read out valence and sea part of parton densities. More...
 
virtual 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 void setVMDscale (double=1.)
 Allow for new scaling factor for VMD PDFs.
 

Additional Inherited Members

- Protected Member Functions inherited from PDF
void setValenceContent ()
 Resolve valence content for assumed meson. Possibly modified later. More...
 
void printErr (string errMsg, Info *infoPtr=0)
 Small routine for error printout, depending on infoPtr existing or not.
 
- Protected Attributes inherited from PDF
int idBeam
 Store relevant quantities.
 
int idBeamAbs
 
int idSav
 
int idVal1
 
int idVal2
 
double xSav
 
double Q2Sav
 
double xu
 
double xd
 
double xs
 
double xubar
 
double xdbar
 
double xsbar
 
double xc
 
double xb
 
double xg
 
double xlepton
 
double xgamma
 
double xuVal
 
double xuSea
 
double xdVal
 
double xdSea
 
bool isSet
 
bool isInit
 
double xsVal
 More valence and sea flavors for photon PDFs.
 
double xcVal
 
double xbVal
 
double xsSea
 
double xcSea
 
double xbSea
 
bool hasGammaInLepton
 True if a photon beam inside a lepton beam, otherwise set false.
 

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 
)
virtual

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 
)
virtual

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 
)
virtual

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: