Weak-U(1) × strong-U(1) effective gauge field theories and electron-monopole scattering

Abstract

We present a gauge and Lorentz invariant model for the scattering of matter off magnetic poles, which justifies the presence of velocity-dependent magnetic charges as an effective description of either the behaviour of monopoles in scattering with matter or their production from matter particles at colliders. Hence, in such an approach, perturbativity of the magnetic charge is ensured for relative low velocities of monopoles with respect to matter particles. The model employs a U(1) weak × U(1) strong effective gauge field theory under which electrons and monopoles (assumed to be fermions) are appropriately charged. The non-perturbative quantum effects of the strongly coupled sector of the theory lead to dressed effective couplings of the monopole/dyon with the electromagnetic photon, due to non-trivial wave-function renormalization effects. For slowly-moving monopole/dyons, such effects lead to weak coupling, thus turning the bare non-perturbative magnetic charge, which is large due to the Dirac/Schwinger quantization rule, into a perturbative effective, velocity-("β")-dependent magnetic coupling. Our work thus offers formal support to previous conjectural studies, employing effective U(1)-electromagnetic gauge field theories for the description of monopole production from Standard Model matter, which are used in contemporary collider searches of such objects. This work necessarily pertains to composite monopoles, as seems to be the case of all known monopoles so far, that are solutions of specific particle physics models. This is a consequence of the fact that the wave-function renormalization of the (slowly-moving) monopole fermion turns out to violate unitarity bounds that would characterise asymptotic elementary particle states.

MoEDAL-MAPP - Detectors specialised for LLP searches

“…This large monopole-photon coupling invalidates any perturbative treatment of the cross-section calculation and hence any result based on it is indicative only. One way to resolve this problem is to use resummation techniques in monopoles [65] and HECOs [66]. Another way to evade it is the Schwinger production in heavy-ion collisions [67].…”

Results and future plans of the MoEDAL experiment

“…MoEDAL is designed to fully exploit the energy-loss mechanisms of magnetically charged particles [11][12][13][14] in order to optimise its potential to discover these messengers of new physics. Various theoretical scenarios foresee the production of magnetic charge at the LHC [4,15]: (light) 't Hooft-Polyakov monopoles [13,14,16], electroweak monopoles [17][18][19][20][21][22][23], global monopoles [24][25][26][27][28][29][30] and monopolium [12,[31][32][33][34][35], a monopole-pair bound state. Magnetic monopoles and dyons, possessing both magnetic and electric charge [36], are fascinating hypothetical particles.…”

MoEDAL, MAPP and future endeavours

“…MoEDAL is designed to fully exploit the energy-loss mechanisms of magnetically charged particles [22][23][24][25] in order to optimise its potential to discover these elusive particles. Various theoretical scenarios foresee the production of magnetic charge at the LHC [7,26]: (light) 't Hooft-Polyakov monopoles [24,25,27], electroweak monopoles [28][29][30][31][32][33], global monopoles [34][35][36][37][38][39][40], monopoles in Born-Infeld theory [41,42] and monopolium [23,[43][44][45][46][47], a monopole-pair bound state. Magnetic monopoles and dyons -the latter possessing both magnetic and electric charge [48] -are fascinating hypothetical particles.…”