Process definition and generation

Process definition

define_process_rcl(npr,process,order)

Defines a process via the process string process at order order and assigns the process id npr to it.

Coupling power selection

The orders associated to couplings for a given theory define a power-counting according to which amplitudes are ordered and computed. For theories with an SM-like gauge group the electric charge \(e\) and the strong coupling constant \(g_\mathrm{s}\) are identified as fundamental couplings. They define the fundamental order and the derived order for other couplings and counterterm parameters:

Coupling	Order
\(g_\mathrm{s}\)	\(\mathrm{QCD}^1\)
\(\alpha_\mathrm{s}\)	\(\mathrm{QCD}^2\)
\(e\)	\(\mathrm{QED}^1\)
\(\alpha\)	\(\mathrm{QED}^2\)
…

Processes can be defined requesting a particular order in fundamental couplings. For SM-like gauge group it is enough to select specific powers of \(g_\mathrm{s}\) and the corresponding valid orders in \(e\) are automaically selected. The selections are applied using one of the following functions:

select_all_gs_powers_BornAmpl_rcl(npr)	Selects all the contribution to the Born amplitude for the process with process number npr.
unselect_all_gs_powers_BornAmpl_rcl(npr)	Unselects all the contribution to the Born amplitude for the process with process number npr.
select_gs_power_BornAmpl_rcl(npr,gspower)	Selects the contribution to the Born amplitude with \(g_\mathrm{s}\) power gspower for the process with process number npr.
unselect_gs_power_BornAmpl_rcl(npr,gspower)	Unselects the contribution to the Born amplitude with \(g_\mathrm{s}\) power gspower for the process with process number npr.
select_all_gs_powers_LoopAmpl_rcl(npr)	Selects all the contribution to the Born amplitude for the process with process number npr.
unselect_all_gs_powers_LoopAmpl_rcl(npr)	Unselects all the contribution to the Born amplitude for the process with process number npr.
select_gs_power_LoopAmpl_rcl(npr, gspower)	Selects the contribution to the Loop amplitude with \(g_\mathrm{s}\) power gspower for the process with process number npr.
unselect_gs_power_LoopAmpl_rcl(npr,gspower)	Unselects the contribution to the Loop amplitude with \(g_\mathrm{s}\) power gspower for the process with process number npr.

For theories with more than two fundamental orders or in EFT the following functions should be used:

select_power_BornAmpl_rcl(npr,cid,pow)	Selects for the process with process number npr the contribution to the Born amplitude with power pow in the fundamental order cid.
unselect_power_BornAmpl_rcl(npr,cid,pow)	Selects the contributions to the Born amplitude with power power of the fundanmetal order cid for the process with identifier npr.
select_all_powers_BornAmpl_rcl(npr)	Selects all contributions to the Born amplitude with any power of orders.
unselect_all_powers_BornAmpl_rcl(npr)	Unselects all contributions to the Born amplitude with any power of orders.
select_power_LoopAmpl_rcl(npr,cid,pow)	Selects for the process with process number npr the contribution to the Loop amplitude with power power in the fundamental order cid.
unselect_power_LoopAmpl_rcl()	Selects all contributions to the Loop amplitude with any power of orders.
select_all_powers_LoopAmpl_rcl(npr)	Selects all contributions to the Loop amplitude with any power of orders.
unselect_all_powers_LoopAmpl_rcl(npr)	Unselects all contributions to the Loop amplitude with any power of orders.

Resonance selection

set_resonant_squared_momentum_rcl(npr,res,ps)	Sets for the resonance with resonance number res for the process with process number npr the squared momentum of the denominator of the resonant propagator to ps.
set_resonant_particle_rcl(pname)	Tags the particle with name pname as resonant.
switchon_resonant_selfenergies_rcl	Sets the value of resSE to .true.
switchoff_resonant_selfenergies_rcl	Sets the value of resSE to .true.

Quark-flow selection

set_quarkline_rcl(npr,q1,q2)

Enforces a quark-flow between two quarks q1 and q2.

Process generation

generate_processes_rcl()	Generates processes which were defined using define_process_rcl().
process_exists_rcl(npr)	Returns whether a process with id npr exists after generation generate_processes_rcl().