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Ultra Minimal Technicolor and its Dark Matter TIMP

Thomas A. Ryttov, Francesco Sannino

TL;DR

The paper presents Ultra Minimal Technicolor (UMT), a near-conformal technicolor model with SU(2) gauge dynamics, two fundamental Dirac technifermions, and two adjoint Weyl fermions, achieving a minimal naive $S$ parameter while producing a Technicolor Interacting Massive Particle (TIMP) as a cold DM candidate. By employing the conjectured all-orders beta function, the authors justify the model's proximity to the conformal window and detail the global symmetry breaking pattern $G=SU(4) imes SU(2) imes U(1) \rightarrow H=Sp(4) imes SO(2) imes Z_2$, including a two-scale dynamics and an electroweak embedding. They construct both linear and non-linear low-energy effective Lagrangians, identify the composite spectrum via matrices $M_4$ and $M_2$, and derive mass eigenstates and ETC-induced mass terms, enabling SM interactions to be embedded within the global symmetries. The TIMP emerges as a viable DM candidate with potentially light mass accessible at the LHC, and relic-density considerations link TB/B to the SM lepton/baryon asymmetry, while CDMS constraints are evaded due to suppressed couplings. Overall, the work provides a coherent framework connecting EWSB, DM, and collider phenomenology through explicit symmetry breaking and EFT constructions.

Abstract

We introduce an explicit model with technifermion matter transforming according to multiple representations of the underlying technicolor gauge group. The model features simultaneously the smallest possible value of the naive S parameter and the smallest possible number of technifermions. The chiral dynamics is extremely rich. We construct the low-energy effective Lagrangian. We provide both the linearly and non-linearly realized ones. We then embed, in a natural way, the Standard Model (SM) interactions within the global symmetries of the underlying gauge theory. Several low-energy composite particles are SM singlets. One of these Technicolor Interacting Massive Particles (TIMP)s is a natural cold dark matter (DM) candidate. We estimate the fraction of the mass in the universe constituted by our DM candidate over the baryon one. We show that the new TIMP, differently from earlier models, can be sufficiently light to be directly produced and studied at the Large Hadron Collider (LHC).

Ultra Minimal Technicolor and its Dark Matter TIMP

TL;DR

The paper presents Ultra Minimal Technicolor (UMT), a near-conformal technicolor model with SU(2) gauge dynamics, two fundamental Dirac technifermions, and two adjoint Weyl fermions, achieving a minimal naive parameter while producing a Technicolor Interacting Massive Particle (TIMP) as a cold DM candidate. By employing the conjectured all-orders beta function, the authors justify the model's proximity to the conformal window and detail the global symmetry breaking pattern , including a two-scale dynamics and an electroweak embedding. They construct both linear and non-linear low-energy effective Lagrangians, identify the composite spectrum via matrices and , and derive mass eigenstates and ETC-induced mass terms, enabling SM interactions to be embedded within the global symmetries. The TIMP emerges as a viable DM candidate with potentially light mass accessible at the LHC, and relic-density considerations link TB/B to the SM lepton/baryon asymmetry, while CDMS constraints are evaded due to suppressed couplings. Overall, the work provides a coherent framework connecting EWSB, DM, and collider phenomenology through explicit symmetry breaking and EFT constructions.

Abstract

We introduce an explicit model with technifermion matter transforming according to multiple representations of the underlying technicolor gauge group. The model features simultaneously the smallest possible value of the naive S parameter and the smallest possible number of technifermions. The chiral dynamics is extremely rich. We construct the low-energy effective Lagrangian. We provide both the linearly and non-linearly realized ones. We then embed, in a natural way, the Standard Model (SM) interactions within the global symmetries of the underlying gauge theory. Several low-energy composite particles are SM singlets. One of these Technicolor Interacting Massive Particles (TIMP)s is a natural cold dark matter (DM) candidate. We estimate the fraction of the mass in the universe constituted by our DM candidate over the baryon one. We show that the new TIMP, differently from earlier models, can be sufficiently light to be directly produced and studied at the Large Hadron Collider (LHC).

Paper Structure

This paper contains 12 sections, 79 equations, 3 figures, 1 table.

Table of Contents

  1. Introduction
  2. From the Conformal Window to Ultra Minimal Technicolor
  3. The Model
  4. Low Energy Spectrum
  5. Linear Lagrangian
  6. Non-Linear Lagrangian
  7. The TIMP
  8. Summary and Outlook
  9. SU(4)$\times$SU(2)$\times$U(1) Generators
  10. Dark Matter Computations
  11. 2nd Order Phase Transition
  12. 1st Order Phase Transition

Figures (3)

  • Figure 1: Contour plot diagram in the $\xi$ and $m_{TB}$ parameter space representing different values assumed by the ratio $\Omega_{TB}/\Omega_B$. Within our approximations the regions depend on the ratio $T_{\ast}/m_{TQ}$. $T_{\ast}$ is the temperature below which the processes violating the baryon, technibaryon and lepton numbers cease to be relevant and $m_{TQ}$ the dynamical mass of the techniquarks. The plots correspond to eight distinct values of this ratio.
  • Figure 2: The expected number of counts in a Germanium detector for an effective exposure of $121.3\ (\text{kg}\ \text{day})$ and recoil energies in the range $5-100\ \text{keV}$. The dashed curve corresponds to $\Lambda_{TC} = 2\ \text{TeV}$ while the solid curve corresponds to $\Lambda_{TC} = 3\ \text{TeV}$.
  • Figure :