Abstract
Anomalous self-interactions of non-abelian gauge fields can be described by higher dimensional operators featuring gauge-invariant combinations of the field strengths. In the case of QCD, the gluon self-interactions start to be modified at dimension six by operators of the type GGG, with G the gluon field strength tensor, possibly leading to deviations in all observables and measurements that probe strong interactions at very small distances. In this work we consider the sensitivity to the triple gluon operator of a series of observables at the LHC in di-jet, three- and multi-jet final states and heavy-quark production. We critically re-examine the robustness of long-standing as well as more recent proposals addressing issues such as the validity of the EFT expansion and the impact of higher order QCD corrections. Our results support the conclusion that multi-jet observables can reliably bound these anomalous interactions to the level that their impact on other key observables at the LHC, involving for example top quark and Higgs production, can be safely neglected. We also highlight the potential of using previously suggested angular observables in three-jet events at the LHC to further constrain these interactions.
Highlights
Which all respect the SM gauge symmetries
Λ is taken to be larger than both v, the Electr√o-Weak Symmetry Breaking (EWSB) scale in the SM, and the characteristic energy scale s at which the measurement is performed, i.e., v/Λ < 1 and s/Λ2 < 1
A first example is that of the four-light-quark interactions, that could be mediated by new bosons, either gauge or scalars, even at the tree level
Summary
The stringent bound set on OG in [13] using the high-multiplicity jet measurements is intriguing. 2.1 OG effects and jet multiplicity The first interesting observation of [13] is the fact that the sensitivity of ST on OG increases with the number of jets We have reproduced this observation, where we show results for the production of 2, 3 and 4 partonic jets in the SM, considering amplitudes with at most one OG operator insertion and including the O(1/Λ4) contribution from the square of these amplitudes. Contributions from the square of amplitudes for the subprocesses with two and four gluons and featuring exactly one OG operator insertion lead to terms of order O(1/Λ4), while the OG operator cannot contribute to the four-quark process Overall, this suppresses the OG contribution to di-jet production and make it small compared to the SM yield, especially for large Bjorken x’s where the quark-initiated processes dominate. Given the recent progress in quark/gluon discrimination, see, e.g., [15], we deem this could be an interesting direction to explore in the future
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
