Strong signatures of right-handed compositeness

Abstract

Right-handed light quarks could be significantly composite, yet compatible with experimental searches at the LHC and precision tests on Standard Model couplings. In these scenarios, that are motivated by flavor physics, one expects large cross sections for the production of new resonances coupled to light quarks. We study experimental strong signatures of right-handed compositeness at the LHC, and constrain the parameter space of these models with recent results by ATLAS and CMS. We show that the LHC sensitivity could be significantly improved if dedicated searches were performed, in particular in multijet signals.

Light non-degenerate composite partners at the LHC

“…Sizable dijet contributions arise in the presence of a light color octet vector resonance in the effective theory [31,32,35,37]. Even if such a state is absent, as assumed here, new physics dijet sources are generically induced by unknown physics at the cut-off scale Λ ∼ 4πf .…”

“…The estimates for the partial widths of the singlet can be easily obtained from ref. [37]. In the limit of a light singlet mŨ < m ρ , m ρ being the gauge resonance mass, and for couplings among the heavy states of order m ρ /f , the decay channelŨ → hj is always dominant.…”

“…This possibility leads to a series of interesting experimental consequences which have been partially discussed in ref. [31,32,[34][35][36][37]. We focus here on analysing signals which could be already probed by direct searches at the LHC.…”

“…As pointed out in ref. [37], two higher-order effective operators can be relevant for the singlet decay. The first one is the loop-generated chromomagnetic operator, which leads to a decay into two jets (Ũ → qg).…”

“…In the partially composite case the combined 95% CL bounds for y x R = 1 are for up and charm partners, respectively. Reference [37] reported stringent bounds on the right-handed charm (and top) partners in cases where both strong dynamics mass parameters and right-handed mixings are flavor universal. These strong bounds are dominantly driven by the first generation partners whose production cross sections at hadron colliders are sustained by relatively large upquark PDFs.…”