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Strong-Weak Bi-Adjoints, Gluon-W resonances, and new asymmetric LHC production processes

Linda M. Carpenter, Katherine Schwind

TL;DR

This work analyzes a novel color-octet, SU(2) triplet scalar in the (8,3,0) representation, coupled to SM gauge bosons via a dimension-5 operator L = \frac{1}{\Lambda} \phi^{ij} W^{\mu\nu}_{ij} G_{\mu\nu}. By constructing both real and complex bi-adjoint models, it derives mass spectra, decays (notably φ^{±} → Wg and φ^0 → Zg/γg), and a rich set of production channels at the LHC, with single production becoming dominant for TeV-scale masses. A key contribution is the proposal of an asymmetric LHC search channel in quark-gluon fusion producing φ^{±} in association with a forward jet, followed by φ^{±} → Wg, yielding a distinctive ℓνg + jet signature. HL-LHC projections indicate a 5σ discovery reach for m_{φ^{±}} up to about 3 TeV with Λ ~ 10 TeV, and 2σ sensitivity extending to higher cutoffs and masses, illustrating the potential to probe W-gluon portal dynamics for high-charge exotics. The study lays groundwork for broader EFT explorations of bi-adjoint states and motivates UV completions and searches for related exotics in future collider runs.

Abstract

We study a novel production and decay mechanism for a bi-adjoint spin zero particle in the ($8,3,0$) representation of the Standard Model gauge groups. This work is part of a series studying new production processes for exotic particles in higher representations of Standard Model color and weak charge. Here, we study a specific new dimension 5 effective operator model which couples an exotic bi-adjoint scalar field to the SU(3) and SU(2) field strength tensors. The W-gluon resonant decay of the charged component of this new exotic field is explored. We discuss LHC production modes of both the charged and neutral bi-adjoint states and find a new single production mode for the charged state. This is the dominant LHC production mode for TeV-scale masses. We introduce a new HL-LHC search in which a single bi-adjoint is produced in association with a hard forward quark jet from asymmetric W-gluon fusion. This search yields a 5-sigma discovery potential for bi-adjoint masses up to 3 TeV for 10 TeV scalar effective operator cutoffs. We also find 2-sigma sensitivity at the HL-LHC for bi-adjoint masses up to 4 TeV and effective cutoffs in the 15 TeV range for the full 3 inverse atto-barn data set.

Strong-Weak Bi-Adjoints, Gluon-W resonances, and new asymmetric LHC production processes

TL;DR

This work analyzes a novel color-octet, SU(2) triplet scalar in the (8,3,0) representation, coupled to SM gauge bosons via a dimension-5 operator L = \frac{1}{\Lambda} \phi^{ij} W^{\mu\nu}_{ij} G_{\mu\nu}. By constructing both real and complex bi-adjoint models, it derives mass spectra, decays (notably φ^{±} → Wg and φ^0 → Zg/γg), and a rich set of production channels at the LHC, with single production becoming dominant for TeV-scale masses. A key contribution is the proposal of an asymmetric LHC search channel in quark-gluon fusion producing φ^{±} in association with a forward jet, followed by φ^{±} → Wg, yielding a distinctive ℓνg + jet signature. HL-LHC projections indicate a 5σ discovery reach for m_{φ^{±}} up to about 3 TeV with Λ ~ 10 TeV, and 2σ sensitivity extending to higher cutoffs and masses, illustrating the potential to probe W-gluon portal dynamics for high-charge exotics. The study lays groundwork for broader EFT explorations of bi-adjoint states and motivates UV completions and searches for related exotics in future collider runs.

Abstract

We study a novel production and decay mechanism for a bi-adjoint spin zero particle in the () representation of the Standard Model gauge groups. This work is part of a series studying new production processes for exotic particles in higher representations of Standard Model color and weak charge. Here, we study a specific new dimension 5 effective operator model which couples an exotic bi-adjoint scalar field to the SU(3) and SU(2) field strength tensors. The W-gluon resonant decay of the charged component of this new exotic field is explored. We discuss LHC production modes of both the charged and neutral bi-adjoint states and find a new single production mode for the charged state. This is the dominant LHC production mode for TeV-scale masses. We introduce a new HL-LHC search in which a single bi-adjoint is produced in association with a hard forward quark jet from asymmetric W-gluon fusion. This search yields a 5-sigma discovery potential for bi-adjoint masses up to 3 TeV for 10 TeV scalar effective operator cutoffs. We also find 2-sigma sensitivity at the HL-LHC for bi-adjoint masses up to 4 TeV and effective cutoffs in the 15 TeV range for the full 3 inverse atto-barn data set.
Paper Structure (9 sections, 16 equations, 1 figure, 1 table)

This paper contains 9 sections, 16 equations, 1 figure, 1 table.

Table of Contents

  1. I. Introduction
  2. II. Model
  3. Parameter space benchmark
  4. III. Decays of the Bi-Adjoints
  5. IV. LHC Production modes
  6. Pair Production
  7. Single Production of Charged Bi-Adjoint Scalars
  8. V. LHC Search for Charged Bi-Adjoints
  9. VI. Conclusions

Figures (1)

  • Figure : Figure 7. Single Production modes of the charged ($8,3,0$) bi-adjoint at the LHC, with subsequent decay $\phi^{\pm}\rightarrow W^{\pm}g$.