Stop-lepton associated production at hadron colliders

Abstract

At hadron colliders, the search for R-parity violating supersymmetry can probe scalar masses beyond what is covered by pair production processes. We evaluate the next-toleading order SUSY-QCD corrections to the associated stop or sbottom production with a lepton through R-parity violating interactions. We show that higher order corrections render the theoretical predictions more stable with respect to variations of the renormalization and factorization scales and that the total cross section is enhanced by a factor up to 70% at the Tevatron and 50% at the LHC. We investigate in detail how the heavy supersymmetric states decouple from the next-to-leading order process, which gives rise to a theory with an additional scalar leptoquark. In this scenario the inclusion of higher order QCD corrections increases the Tevatron reach on leptoquark masses by up to 40 GeV and the LHC reach by up to 200 GeV.

Novel leptoquark pair production at LHC

“…As it turns out, the t-channel contribution of figure 1 towards the leptoquark pair production at LHC becomes relevant only when the leptoquark interacts very strongly, i.e., with the couplings of order one, to the quarks of the first generation [55]. However, in this particular regime other processes such as a single leptoquark production [55][56][57][58], induced by the diagrams in panels (b) and (c) of figure 1, the Drell-Yan di-lepton production [59][60][61][62][63][64], and/or a resonant leptoquark production [65][66][67][68] might become equally capable of or even more important in constraining the leptoquark parameter space. Moreover, one also needs to take into account the experimental constraints from flavor physics, such as the Atomic Parity Violation ones, for a given l-q-LQ scenario to ensure its viability, especially within a large Yukawa coupling regime [69] space see ref.…”

Lepton-quark fusion at Hadron colliders, precisely

“…However, the production of two leptoquarks becomes quickly phase-space suppressed with increasing leptoquark mass. Therefore, often discussed in the literature is the single leptoquark plus lepton production from quark-gluon scattering [23,[37][38][39]. A representative Feynman diagram is shown in figure 1 (b).…”

Revisiting scalar leptoquark at the LHC

“…The results for three different production cross-sections are shown: q g → φ + X in green, b g → φ ν in red and c g → φ µ in blue. The k-factor of 1.5 has been taken into account [39]. The leptoquark will decay to combinations of quark and lepton.…”