PYTHIA  8.303
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AlphaEM Class Reference

#include <StandardModel.h>

Public Member Functions

 AlphaEM ()
void init (int orderIn, Settings *settingsPtr)
 Initialization for a given order. More...
double alphaEM (double scale2)
 alpha_EM value. More...

Detailed Description

The AlphaEM class calculates the alpha_electromagnetic value at an arbitrary scale, given the value at 0 and m_Z, to zeroth or first order.

Member Function Documentation

double alphaEM ( double  scale2)

alpha_EM value.

Calculate alpha_EM value.

Fix alphaEM; for order = -1 fixed at m_Z.

Running alphaEM.

void init ( int  orderIn,
Settings settingsPtr 

Initialization for a given order.

Initialize alpha_EM calculation.

Order. Read in alpha_EM value at 0 and m_Z, and mass of Z.

AlphaEM values at matching scales and matching b value.

Step down from mZ to tau/charm threshold.

Step up from me to light-quark threshold.

Fit b in range between light-quark and tau/charm to join smoothly.

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