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QQbar_threshold
constants.hpp File Reference

Physical constants. More...

Go to the source code of this file.

Namespaces

 QQbar_threshold
 

Functions

double axial_Z_coupling (double T3, double)
 Axial vector coupling of fermion to Z boson. More...
 
double vector_Z_coupling (double T3, double e)
 Vector coupling of fermion to Z boson. More...
 

Variables

constexpr double alpha_s_mZ = 0.1184
 Default value for strong coupling at the scale mZ.
 
constexpr double alpha_mZ = 1/128.944
 QED coupling at the scale mZ.
 
constexpr double alpha_Y = 1/132.274
 QED coupling at the scale mu_alpha_Y.
 
constexpr double mu_alpha_Y = 10.2
 Typical scale for Y resonances.
 
constexpr double mZ = 91.1876
 Mass of the Z boson.
 
constexpr double mW = 80.385
 Mass of the W boson.
 
constexpr double me = 0.0005109989461
 Electron mass.
 
constexpr double G_F = 0.000011663787
 Fermi constant - this is exclusively used for calculating the top width.
 
constexpr double m_Higgs = 125.
 Default value for mass of the Higgs boson.
 
constexpr double alpha_QED = 1/137.035999074
 Fine structure constant.
 
constexpr double e_u = 2./3.
 Electric charge of the top quark in units of the positron charge.
 
constexpr double e_d = -1./3.
 Electric charge of the bottom quark in units of the positron charge.
 
constexpr double e = -1
 Electric charge of the electron in units of the positron charge.
 
constexpr double cw2 = mW*mW/(mZ*mZ)
 cosine of the weak mixing angle squared
 
constexpr double sw2 = 1 - cw2
 sine of the weak mixing angle squared
 
constexpr double T3_nu = 1./2.
 Weak isospin of neutrino.
 
constexpr double T3_e = -1./2.
 Weak isospin of electron.
 
constexpr double T3_u = 1./2.
 Weak isospin of top.
 
constexpr double T3_d = -1./2.
 Weak isospin of bottom.
 
constexpr double mb_SI = 4.203
 Reference scale-invariant mass for bottom quarks.
 
constexpr double mu_thr = 2*mb_SI
 Decoupling threshold for bottom quarks.
 
constexpr int nl_bottom = 4
 Number of light flavours for bottom-related functions.
 
constexpr int nl_top = 5
 Number of light flavours for top-related functions.
 
constexpr double mu_f_bottom = 2.
 Default PS scale for bottom.
 
constexpr double mu_f_top = 20.
 Default PS scale for top.
 
constexpr double invGeV2_to_pb = 389379300.
 Conversion factor from 1/GeV^2 to picobarn.
 

Detailed Description

Physical constants.

Changes to the constants may require a recompilation of the whole QQbar_threshold library to take effect. Wherever possible, it is recommended to change settings via the options parameter of the QQbar_threshold functions instead.

Author
Andreas Maier a.mai.nosp@m.er@t.nosp@m.um.de
Version
2.2.0

LICENSE

Copyright 2014, 2015, 2016 Andreas Maier

This file is part of the QQbar_threshold library.

The QQbar_threshold library is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

The QQbar_threshold library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with the QQbar_threshold library. If not, see http://www.gnu.org/licenses/.