include/apfel/betaqcd.h

0001 //
0002 // APFEL++ 2017
0003 //
0004 // Author: Valerio Bertone: valerio.bertone@cern.ch
0005 //
0006
0007 #pragma once
0008
0009 namespace apfel
0010 {
0011   /**
0012    * @name QCD beta function
0013    * Coefficients of the QCD \f$\beta\f$ function.
0014    * Reference: https://arxiv.org/pdf/1701.01404.pdf
0015    */
0016   ///@{
0017   /**
0018    * @brief LO coefficient of the QCD \f$\beta\f$ function.
0019    * @param nf: the number of active flavours
0020    * @return \f$\beta_0(n_f)\f$
0021    */
0022   double beta0qcd(int const& nf);
0023
0024   /**
0025    * @brief NLO coefficient of the QCD \f$\beta\f$ function.
0026    * @param nf: the number of active flavours
0027    * @return \f$\beta_1(n_f)\f$
0028    */
0029   double beta1qcd(int const& nf);
0030
0031   /**
0032    * @brief NNLO coefficient of the QCD \f$\beta\f$ function.
0033    * @param nf: the number of active flavours
0034    * @return \f$\beta_2(n_f)\f$
0035    */
0036   double beta2qcd(int const& nf);
0037
0038   /**
0039    * @brief NNNLO coefficient of the QCD \f$\beta\f$ function.
0040    * @param nf: the number of active flavours
0041    * @return \f$\beta_3(n_f)\f$
0042    */
0043   double beta3qcd(int const& nf);
0044
0045   /**
0046    * @brief N4LO coefficient of the QCD \f$\beta\f$ function.
0047    * @param nf: the number of active flavours
0048    * @return \f$\beta_4(n_f)\f$
0049    */
0050   double beta4qcd(int const& nf);
0051   ///@}
0052 }