constants.hpp File Reference

Physical constants. More...

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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	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

1.1.0

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/.