Scalar Representations and Minimal Flavor Violation

TL;DR

The work classifies new scalar states capable of renormalizable couplings to quarks under minimal flavor violation, including color sextets and anti-sextets, and builds explicit tree-level Lagrangians for cases V–XII where these couplings do not require insertions of SM Yukawas. It demonstrates that gauge symmetry together with MFV often enforces baryon-number conservation and analyzes the resulting phenomenology, showing that EWPD and LEP II impose $m_S\gtrsim 100$ GeV while Tevatron dijet searches push viable masses higher for sizable couplings; the scalars can also influence Higgs production and decay via loop-induced effective operators. The framework makes concrete predictions for collider signatures, including dijet resonances, multi-jet final states, and potential modifications to Higgs signals, and highlights the LHC’s potential to discover or constrain these MFV-consistent colored scalars with early data. Collectively, the paper provides a predictive, flavor-safe avenue to explore diquark-like scalars at high-energy colliders and integrates collider, electroweak, and low-energy constraints within MFV.

Abstract

We discuss the representations that new scalar degrees of freedom (beyond those in the minimal standard model) can have if they couple to quarks in a way that is consistent with minimal flavor violation. If the new scalars are singlets under the flavor group then they must be color singlets or color octets. In this paper we discuss the allowed representations and renormalizable couplings when the new scalars also transform under the flavor group. We find that color \bar{3} and 6 representations are also allowed. We focus on the cases where the new scalars can have renormalizable Yukawa couplings to the quarks without factors of the quark Yukawa matrices. The renormalizable couplings in the models we introduce automatically conserve baryon number.

Figures (2)

• Figure 1: The oblique corrections of the colored scalars of cases V thru XII.
• Figure 2: The one loop joint fits of cases $V,VI,VIII,X$ and the Higgs mass (that is floated at one loop in the EWPD according to the procedure described in Burgess:2009wm). The red (solid grey) region is the $68 \%$ confidence region defined through the cumulative distribution function while the blue (dotted black) region is the $95 \%$ confidence region. Only case VI allows the fitted value of the Higgs mass to be raised significantly when the LEPII direct production bound of $m_S > 105 \, {\rm GeV}$ is imposed. The cases VII,IX not shown have a negligible impact on the fitted value of the Higgs mass at one loop. More dramatic effects on the fitted value of the Higgs mass are possible for cases I-IV and XIII-XIV due to the possibility of positive contributions of $\Delta {\rm T}$.