We calculate the $\textit{θ}$ dependence in a cousin of QCD, where the vacuum structure can be analyzed exactly. The theory is $$ \mathcal{N} $$ = 2 SU(2) gauge theory with $\textit{N}$ = 0, 1, 2, 3 flavors of fundamentals, explicitly broken to $$ \mathcal{N} $$ = 1 via an adjoint superpotential, and coupled to anomaly mediated supersymmetry breaking (AMSB). The hierarchy $\textit{m}$ ≪ $\textit{μ}$ ≪ Λ ensures the validity of our IR analysis. As expected from ordinary QCD, the vacuum energy is a function of $\textit{θ}$ which undergoes 1st order phase transitions between different vacua where the various dyons condense. For $\textit{N}$ = 0 we find the expected phase transition at $\textit{θ}$ = $\textit{π}$, while for $\textit{N}$ = 1, 2, 3 we find phase transitions at fractional values of $\textit{π}$.

United States

Csaba Csáki

Japan

Teruhiko Kawano

Hitoshi Murayama

Israel

Ofri Telem

Phase transitions at unusual values of $\textit{θ}$

We present a composite QCD axion model where the Peccei-Quinn symmetry emerges as a high-quality, accidental symmetry. The axion potential is only modified by eight-fermion, dimension-12 operators, which if present at the Planck scale, allow for axion dark matter from misalignment while solving the strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> problem. The model is an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>SU</mi><mo stretchy="false">(</mo><msub><mi>N</mi><mi>c</mi></msub><mo stretchy="false">)</mo></math> gauge theory with ten flavors where the Pati-Salam unified subgroup <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>SO</mi><mo stretchy="false">(</mo><mn>6</mn><mo stretchy="false">)</mo><mo>×</mo><mi>SO</mi><mo stretchy="false">(</mo><mn>4</mn><mo stretchy="false">)</mo><mo>⊂</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>10</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Sp</mi><mo stretchy="false">(</mo><mn>10</mn><mo stretchy="false">)</mo><mo>⊂</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>10</mn><msub><mo stretchy="false">)</mo><mi>R</mi></msub></math> are weakly gauged. The dynamics breaks <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>SU</mi><mo stretchy="false">(</mo><mn>10</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>10</mn><msub><mo stretchy="false">)</mo><mi>R</mi></msub><mo stretchy="false">→</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>10</mn><msub><mo stretchy="false">)</mo><mi>V</mi></msub></math> and the weakly gauged groups to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo><mo>⊃</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>3</mn><msub><mo stretchy="false">)</mo><mi>c</mi></msub><mo>×</mo><mi>SU</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi mathvariant="normal">U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>Y</mi></msub></math>, with the QCD axion identified as one of the Nambu-Goldstone bosons. This axion has a relatively large coupling to photons while a residual <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover><mi>eff</mi></msub></math> may be just below the current limit on the neutron electric dipole moment. If the dimension-12 operators are present near the grand unified theory scale, they can cause domain wall networks to decay, allowing for axion dark matter even for the postinflationary scenario.

Tony Gherghetta

Pablo Quílez

High-quality composite Pati-Salam axion

Inverse decays are an interesting avenue for producing dark matter in the early Universe. We study in detail various phases of dark matter parameter space where inverse decays control its abundance, expanding on our work of inverse decay (INDY) dark matter and going beyond. The role of initial conditions and the impact of departure from kinetic equilibrium are investigated as well. We show how these inverse decay phases can arise in theories of a kinetically mixed dark photon and dark Higgs, with promising prospects for detection at upcoming experiments.

Ronny Frumkin

Yonit Hochberg

Eric Kuflik

Phases of dark matter from inverse decays

We present exact nonperturbative vacuum solutions to chiral gauge theories based on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>E</mi><mn>6</mn></msub></math> gauge group and several matter fermions in the fundamental <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn mathvariant="bold">27</mn></mrow></math>-dimensional representation. They are obtained when supersymmetric versions are perturbed by small supersymmetry breaking by anomaly mediation. The universality classes obtained are very different from what can be conjectured by the tumbling hypothesis. In particular, the case with three <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn mathvariant="bold">27</mn><mi mathvariant="normal">s</mi></mrow></math> may have an unbroken SU(3) symmetry with massless composite fermions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn mathvariant="bold">10</mn></mrow></math> of SU(3). For this case, we employed numerical techniques to obtain the exact ground state.

Andrew Goh

Gup Singh

Bethany Suter

Jason Wong

Dynamics of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>E</mi><mn>6</mn></msub></math> chiral gauge theories

We present exact results in softly broken supersymmetric <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>SU</mi><mo stretchy="false">(</mo><msub><mi>N</mi><mi>C</mi></msub><mo stretchy="false">)</mo></math> chiral gauge theories with charged fermions in one antisymmetric, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>F</mi></msub></math> fundamental, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>C</mi></msub><mo>+</mo><msub><mi>N</mi><mi>F</mi></msub><mo>−</mo><mn>4</mn></math> antifundamental representations. We achieve this by considering the supersymmetric version of these theories and utilizing anomaly mediated supersymmetry breaking at a scale <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo>≪</mo><mi mathvariant="normal">Λ</mi></math> to generate a vacuum. The connection to nonsupersymmetric theories is then conjectured in the limit <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo stretchy="false">→</mo><mi>∞</mi></math>. For odd <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>C</mi></msub></math>, we determine the massless fermions and unbroken global symmetries in the infrared. For even <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>C</mi></msub></math>, we find global symmetries are nonanomalous and no massless fermions. In all cases, the symmetry breaking patterns differ from what the tumbling hypothesis would suggest.

Czechia

Jacob M. Leedom

Exact results in softly broken supersymmetric chiral gauge theories with flavor

We show that near the edges of the conformal window of supersymmetric SU($\textit{N}$ ) QCD, perturbed by Anomaly Mediated Supersymmetry Breaking (AMSB), chiral symmetry can be broken depending on the initial conditions of the RG flow. We do so by perturbatively expanding around Banks-Zaks fixed points and taking advantage of Seiberg duality. Interpolating between the edges of the conformal window, we predict that non-supersymmetric QCD breaks chiral symmetry up to $\textit{N}$ ≤ 3$\textit{N}$ − 1, while we cannot say anything definitive for $\textit{N}$ ≥ 3$\textit{N}$ at this moment.

Dan Kondo

Bea Noether

Digvijay Varier

Broken conformal window

We propose to use the nuclear spin excitation in the ferromagnetic A1 phase of the superfluid 3He for the axion dark matter detection. This approach is striking in that it is sensitive to the axion-nucleon coupling, one of the most important features of the QCD axion introduced to solve the strong CP problem. We review a quantum mechanical description of the nuclear spin excitation and apply it to the estimation of the axion-induced spin excitation rate. We also describe a possible detection method of the spin excitation in detail and show that the combination of the squeezing of the final state with the Josephson parametric amplifier and the homodyne measurement can enhance the sensitivity. It turns out that this approach gives good sensitivity to the axion dark matter with the mass of <math> <mi>O</mi> </math> $$ \mathcal{O} $$ (1) μeV depending on the size of the external magnetic field. We estimate the parameters of experimental setups, e.g., the detector volume and the amplitude of squeezing, required to reach the QCD axion parameter space.

So Chigusa

Risshin Okabe

Hiroyuki Sudo

Axion detection via superfluid 3He ferromagnetic phase and quantum measurement techniques

We present a nonperturbative recipe for directly computing the S-matrix in strongly-coupled QFTs. The method makes use of spectral data obtained in a Hamiltonian framework and can be applied to a wide range of theories, including potentially QCD. We demonstrate the utility of this prescription in the specific example of the 2+1d O(N) model at large N, using energy eigenstates computed with Hamiltonian truncation to reproduce the full 2 → 2 scattering amplitude for arbitrary (complex) center-of-mass energy.

Switzerland

Brian Henning

Francesco Riva

Jedidiah Thompson

Ireland

Matthew Walters

Towards a nonperturbative construction of the S-matrix

We propose a new thermal dark matter candidate whose abundance is determined by the freeze-out of inverse decays. The relic abundance depends parametrically only on a decay width, while matching the observed value requires that the coupling determining the width—and the width itself—should be exponentially small. The dark matter is therefore very weakly coupled to the standard model, evading conventional searches. This inverse decay dark matter can be discovered by searching for the long-lived particle that decays into the dark matter at future planned experiments.

Thermal Dark Matter from Freeze-Out of Inverse Decays

We introduce a systematic method to classify the Standard Model Effective Field Theory (SMEFT) operators based on their CP properties with the Hilbert series techniques. Our method makes it possible to enumerate operators violating CP symmetry in a few seconds. We present the complete classification of dimension eight operators under CP transformation, and the number of CP-odd or CP-violating operators are listed up to dimension 14. We also provide a companion code in Form that allows anybody to reproduce our results.

23, 381, 6242, 103268, 1743183, … : Hilbert series for CP-violating operators in SMEFT