pSPSS: Phenomenological symmetry protected seesaw

The pSPSS describes the interactions of a pseudo-Dirac pair of two Majorana degrees of freedom generically appearing in low-scale seesaw models.

SPSS: Symmetry protected seesaw

MadGraph patch

In order to generate events with heavy neutrino-antineutrino oscillations it is necessary to patch the ./bin/internal/common_run_interface.py file with

for event in lhe:
    leptonnumber = 0
    write_event = True
    for particle in event:
        if particle.status == 1:
            if particle.pid in [11, 13, 15]:
                leptonnumber += 1
            elif particle.pid in [-11, -13, -15]:
                leptonnumber -= 1
    for particle in event:
        id = particle.pid
        width = param_card['decay'].get((abs(id),)).value
        mass splitting = param_card.get_value('FRBLOCK', 1)
        if width:
            if id in [8000011, 8000012]:
                tau0 = random.expovariate(width / cst)|\label{ln:tau0}|
                if 0.5 * (1 + math.cos(mass splitting * tau0 / cst)) >= random.random():
                    write_event = (leptonnumber == 0)
                else:
                    write_event = (leptonnumber != 0)
                vtim = tau0 * c|\label{ln:convert_tau0}|
            else:
                vtim = c * random.expovariate(width / cst)
            if vtim > threshold:
                particle.vtim = vtim
    # write this modify event
    if write_event:
        output.write(str(event))
output.write('</LesHouchesEvents>\n')
output.close()