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// ************************************************************************************************
//
// BornAgain: simulate and fit reflection and scattering
//
//! @file Base/Const/PhysicalConstants.h
//! @brief Defines the values of physical constants (SI).
//!
//! @homepage http://www.bornagainproject.org
//! @license GNU General Public License v3 or higher (see COPYING)
//! @copyright Forschungszentrum Jülich GmbH 2018
//! @authors Scientific Computing Group at MLZ (see CITATION, AUTHORS)
//
// ************************************************************************************************
#ifdef SWIG
#error no need to expose this header to Swig
#endif // SWIG
#ifndef BORNAGAIN_BASE_CONST_PHYSICALCONSTANTS_H
#define BORNAGAIN_BASE_CONST_PHYSICALCONSTANTS_H
#include <numbers>
//! Physical constants.
namespace PhysConsts {
constexpr double m_n = 1.67492749804e-27; //!< Neutron mass, kg
constexpr double h_bar = 1.054571817e-34; //!< Reduced Plank constant, J s
constexpr double mu_N = 5.0507837461e-27; //!< Nuclear magneton (\f$ \mu_N \f$), J/T
constexpr double mu_B = 9.2740100783e-24; //!< Bohr magneton (\f$ \mu_B \f$), J/T
constexpr double r_e = 2.8179403262e-15; //!< Thomson scattering length (\f$ r_e \f$), m
constexpr double gamma_n = 1.91304272; //!< \f$\gamma\f$ factor for neutron magnetic moment,
//!< \f$\mu_n = \gamma \cdot \mu_N\f$
constexpr double g_factor_n = -3.82608545; //!< neutron g-factor
constexpr double pi = std::numbers::pi;
} // namespace PhysConsts
#endif // BORNAGAIN_BASE_CONST_PHYSICALCONSTANTS_H
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