Final (main) Block A, describing $q_1 q_2 \to p_1 + p_2 + X$.

$q_1$ and $q_2$ are Bjorken fractions, $p_1$ and $p_2$ are the 4-momenta of the visible particles produced in the process.

This Block addresses the change of variables needed to pass from the standard phase-space parametrization to the $\frac{1}{16\pi^{2} E_1 E_2} d \theta_1 d \theta_2 d \phi_1 d \phi_2 \times J$ parametrization, where $\theta_1$ and $\theta_2$ are the polar angles and $\phi_1$ and $\phi_2$ are the azimuthal angles of the particles labeled with 1 and 2.

The balanced modules $|p_1|$ and $|p_2|$ of the visible particles are computed based on the following set of equations:

• $|p_1| sin \theta_1 cos \phi_1 + |p_2| sin \theta_2 cos \phi_2 = -p_{x}^{branches}$
• $|p_1| sin \theta_1 sin \phi_1 + |p_2| sin \theta_2 sin \phi_2 = -p_{y}^{branches}$ i.e. balance of the transverse momentum $p_{T}^{branches}$ of the particles present in the process.

Only one solution ( $|p_1|, |p_2|$) is possible.

Integration dimension

This module requires 0 phase-space point.

Global parameters

Inputs

Outputs

Note

This block has been validated and is safe to use.

See also

Looper module to loop over the solutions of this Block

Definition at line 78 of file BlockA.cc.