Octet scalars shaping LHC distributions in 4-jet final states, by Bogdan A. Dobrescu, Max H. Fieg

SciPost Physics Home Authoring Refereeing Submit a manuscript About Octet scalars shaping LHC distributions in 4-jet final states Bogdan A. Dobrescu, Max H. Fieg SciPost Phys. 20, 087 (2026) · published 18 March 2026 doi: 10.21468/SciPostPhys.20.3.087 pdf BiBTeX RIS Submissions/Reports Abstract We study properties of a hypothetical scalar particle, $\Theta$, which is a color octet and an electroweak singlet. At hadron colliders, $\Theta$ is pair produced through its QCD coupling to gluons, so that its mass determines the cross section. It decays at tree level into $q\bar q$ through dimension-5 operators, and at one loop into gluons. Thus, the main LHC signature of $\Theta$ is a pair of dijets of equal invariant mass. The CMS search in this channel shows a $3.6\sigma$ excess over the QCD background for a dijet mass $M_{jj} ≈ 0.95$ TeV, which can be due to $\Theta$: its production cross section (65 fb for a real scalar) and the acceptance of the CMS event selection applied to $p p \to \Theta \Theta \to \! (q \bar q)(q \bar q)$ yield a rate consistent with the excess. Furthermore, the shape of the $d\sigma/d M_{jj}$ signal is in agreement with the CMS result. Given the data-driven background fit performed by CMS, we find that a complex scalar (whose production rate is twice as large) fits better the data than a real scalar. Besides the pair of dijets, testable LHC signals include a trijet-dijet topology, a $t\bar t$ pair plus a dijet resonance, as well as final states involving a Higgs, $W$ or $Z$ boson plus jets. × TY - JOURPB - SciPost FoundationDO - 10.21468/SciPostPhys.20.3.087TI - Octet scalars shaping LHC distributions in 4-jet final statesPY - 2026/03/18UR - https://scipost.org/SciPostPhys.20.3.087JF - SciPost PhysicsJA - SciPost Phys.VL - 20IS - 3SP - 087A1 - Dobrescu, Bogdan A.AU - Fieg, Max H.AB - We study properties of a hypothetical scalar particle, $\Theta$, which is a color octet and an electroweak singlet. At hadron colliders, $\Theta$ is pair produced through its QCD coupling to gluons, so that its mass determines the cross section. It decays at tree level into $q\bar q$ through dimension-5 operators, and at one loop into gluons. Thus, the main LHC signature of $\Theta$ is a pair of dijets of equal invariant mass. The CMS search in this channel shows a $3.6\sigma$ excess over the QCD background for a dijet mass $M_{jj} ≈ 0.95$ TeV, which can be due to $\Theta$: its production cross section (65 fb for a real scalar) and the acceptance of the CMS event selection applied to $p p \to \Theta \Theta \to \! (q \bar q)(q \bar q)$ yield a rate consistent with the excess. Furthermore, the shape of the $d\sigma/d M_{jj}$ signal is in agreement with the CMS result. Given the data-driven background fit performed by CMS, we find that a complex scalar (whose production rate is twice as large) fits better the data than a real scalar. Besides the pair of dijets, testable LHC signals include a trijet-dijet topology, a $t\bar t$ pair plus a dijet resonance, as well as final states involving a Higgs, $W$ or $Z$ boson plus jets.ER - × @Article{10.21468/SciPostPhys.20.3.087, title={{Octet scalars shaping LHC distributions in 4-jet final states}}, author={Bogdan A. Dobrescu and Max H. Fieg}, journal={SciPost Phys.}, volume={20}, pages={087}, year={2026}, publisher={SciPost}, doi={10.21468/SciPostPhys.20.3.087}, url={https://scipost.org/10.21468/SciPostPhys.20.3.087},} Ontology / Topics See full Ontology or Topics database. Gauge theory Jets Large Hadron Collider (LHC) Monte-Carlo simulations Authors / Affiliation: mappings to Contributors and Organizations See all Organizations. 1 Bogdan A. Dobrescu, 1 Max H. Fieg 1 Fermi National Accelerator Laboratory [Fermilab] Funder for the research work leading to this publication United States Department of Energy [DOE]