Yonit Hochberg

The SIMPlest Miracle

It has recently been proposed that dark matter could be a thermal relic of 3-to-2 scatterings in a strongly coupled hidden sector. We present explicit classes of strongly coupled gauge theories that admit this behavior. These are QCD-like theories of dynamical chiral symmetry breaking, where the pions play the role of dark matter. The number-changing 3-to-2 process, which sets the dark matter relic abundance, arises from the Wess-Zumino-Witten term. The theories give an explicit relationship between the 3-to-2 annihilation rate and the 2-to-2 self-scattering rate, which alters predictions for structure formation. This is a simple calculable realization of the strongly-interacting-massive-particle (SIMP) mechanism.

Superconducting Detectors for Superlight Dark Matter

We propose and study a new class of superconducting detectors that are sensitive to O(meV) electron recoils from dark matter-electron scattering. Such devices could detect dark matter as light as the warm dark-matter limit, m(X)≳1  keV. We compute the rate of dark-matter scattering off of free electrons in a (superconducting) metal, including the relevant Pauli blocking factors. We demonstrate that classes of dark matter consistent with terrestrial and cosmological or astrophysical constraints could be detected by such detectors with a moderate size exposure.

Vacuum (meta)stability beyond the MSSM

We study the stability of the Higgs potential in the framework of the effective Lagrangian beyond the minimal supersymmetric standard model (MSSM). While the leading nonrenormalizable operators can shift the Higgs boson mass above the experimental bound, they also tend to render the scalar potential unbounded from below. The destabilization is correlated with the Higgs mass increase, so that if quantum corrections are small the problem is severe. We show that a supersymmetric subleading correction stabilizes the potential within the domain of validity of the effective theory. Constraints on MSSM parameters as well as on higher dimensional operators are derived, ensuring that our vacuum has a lifetime longer than the present age of the Universe. In addition we show that when effective operators are responsible for evading the LEP bound, stability constraints imply an upper bound on the scale of new physics in the few TeV range.

Implications of the CDF tt¯ forward–backward asymmetry for boosted top physics

Abstract New physics at a high scale Λ can affect top-related observables at O ( 1 / Λ 2 ) via the interference of effective four quark operators with the SM amplitude. The ( u ¯ γ μ γ 5 T a u ) ( t ¯ γ μ γ 5 T a t ) operator modifies the large M t t ¯ forward–backward asymmetry, and can account for the recent CDF measurement. The ( u ¯ γ μ T a u ) ( t ¯ γ μ T a t ) operator modifies the differential cross section, but cannot enhance the cross section of ultra-massive boosted jets by more than 60%. The hint for a larger enhancement from a recent CDF measurement may not persist future experimental improvements, or may be a QCD effect that is not accounted for by leading order and matched Monte Carlo tools or naive factorization. If it comes from new physics, it may stem from new light states or an O ( 1 / Λ 4 ) new physics effect.

Implications of the CDF

The CDF collaboration has recently reported a large deviation from the standard model of the

t\bar{t}

t\bar{t}

forward-backward asymmetry for hard top physics

forward-backward asymmetry in the high invariant mass region. We interpret this measurement as coming from new physics at a heavy scale Λ, and perform a model-independent analysis up to

Relating direct CP violation in D decays and the forward-backward asymmetry in tt[over ¯] production.

\mathcal{O}\left( {{{1} \left/ {{{\Lambda^4}}} \right.}} \right)

Flavor changing processes in supersymmetric models with hybrid gauge- and gravity-mediation

. A simple formalism to test and constrain models of new physics is provided. We find that a large asymmetry cannot be accommodated by heavy new physics that does not interfere with the standard model. We show that a smoking gun test for the heavy new physics hypothesis is a significant deviation from the standard model prediction for the

What if \( \mathrm{BR}\left( {h\to \mu \mu } \right)/\mathrm{BR}\left( {h\to \tau \tau } \right)\ne m_{\mu}^2/m_{\tau}^2 \) ?

t\bar{t}