Standard Model + Wprime

This model implements the SM supplemented by an interaction term with a \(\mathrm{W}'\) based on [Sul02], [DS12]

\[V_{\mathrm{W}'} = k_\pm \frac{g}{\sqrt{2}} W_\mu' \left(K_{ij} \bar \nu^i \gamma^\mu w^\pm l^j + V_{ij}^\pm \bar u^i \gamma^\mu w^\pm d^j\right) + \mathrm{H.c.},\]

The NLO Recola2 model file has been built using the extended Lagrangian as implemented in WprimeUFO.

Parameter conventions

Parameter Recola identifier default value
\(k_+\), \(k_-\) 'kR', 'kL' 1.0, 0.1
\(V_{11}^-\), \(V_{12}^-\), .. 'CLq1x1', 'CLq1x2', .. \(V_\mathrm{CKM}\)
\(V_{11}^+\), \(V_{12}^+\), .. 'CRq1x1', 'CRq1x2', .. \(V_\mathrm{CKM}\)
\(K_{11}^-\), \(K_{12}^-\), .. 'CLl1x1', 'CLl1x2', .. \(I_3\)
\(K_{11}^+\), \(K_{12}^+\), .. 'CRl1x1', 'CRl1x2', .. \(I_3\)

The SMWP doesn’t come with a dedicated interface, thus, parameters need to be set with the generic function set_parameter_rcl().

Field conventions

Fields Recola identifier
\(\mathrm{W}'^+\), \(\mathrm{W}'^-\) 'Wp+', 'Wp-'

Snippet code using the SMWP

from pyrecola import *

set_print_level_squared_amplitude_rcl(2)

# enable to draw off-shell currents
# set_draw_level_branches_rcl(1)

define_process_rcl(1, 'u d~ -> t b~', 'NLO')
unselect_power_LoopAmpl_rcl(1, 'QCD', 0)

# generate a sample PSP using RAMBO
generate_processes_rcl()

p1 = [500., 0., 0.,  500.]
p2 = [500., 0., 0., -500.]

# generate a sample PSP using RAMBO
p = set_outgoing_momenta_rcl(1, [p1, p2])

# compute tree squared and tree one-loop interference
compute_process_rcl(1, p, 'NLO')

reset_recola_rcl()
use recola

implicit none
integer, parameter :: dp = kind (23d0)
real(dp) :: p(0:3,1:4), A2(2)

call set_print_level_squared_amplitude_rcl(2)

! enable to draw off-shell currents
! call set_draw_level_branches_rcl(1)

call define_process_rcl(1, 'u d~ -> t b~', 'NLO')
call unselect_power_LoopAmpl_rcl(1, 'QCD', 0)

call generate_processes_rcl

p(:,1) = [500d0, 0d0, 0d0,  500d0]
p(:,2) = [500d0, 0d0, 0d0, -500d0]
! generate a sample PSP using RAMBO
call set_outgoing_momenta_rcl(1, p(:,1:2), p)

! compute tree squared and tree one-loop interference
call compute_process_rcl(1, p, 'NLO', A2)
#include "recola.hpp"

Recola::set_print_level_squared_amplitude_rcl(2);

// enable to draw off-shell currents
// Recola::set_draw_level_branches_rcl(1);

Recola::define_process_rcl(1, "u d~ -> t b~", "NLO");

Recola::unselect_power_LoopAmpl_rcl(1, "QCD", 0);

// generate it
Recola::generate_processes_rcl();

// generate a sample PSP using RAMBO
double pin[2][4] =
{{500., 0., 0., 500.},
 {500., 0., 0., -500.}};
double p[4][4];
Recola::set_outgoing_momenta_rcl(1, pin, p);

// compute tree squared and tree one-loop interference
double A2[2];
Recola::compute_process_rcl(1, p, "NLO", A2);

Releases Standard Model + Wprime

References

[DS12]Daniel Duffty and Zack Sullivan. Model independent reach for W-prime bosons at the LHC. Phys. Rev., D86:075018, 2012. arXiv:1208.4858, doi:10.1103/PhysRevD.86.075018.
[Sul02]Zack Sullivan. Fully Differential $W^\prime $ Production and Decay at Next-to-Leading Order in QCD. Phys. Rev., D66:075011, 2002. arXiv:hep-ph/0207290, doi:10.1103/PhysRevD.66.075011.