We present results on the neutron electric dipole moment |𝑑⃗𝑁| using an ensemble of 𝑁𝑓=2+1+1 twisted mass clover-improved fermions with lattice spacing of 𝑎≃0.08 fm and physical pion mass (𝑚𝜋≃139 MeV). We compute the 𝐶𝑃-odd electromagnetic form factor 𝐹3(𝑄2→0) by expanding the action to leading order in 𝜃. This gives rise to correlation functions that involve the topological charge, for which...
As widely known, the discovery of an electric dipole moment (EDM) of the neutron would manifest the invariance time reversal and violate the combined symmetry of charge and parity (CP). At current experimental sensitivities an univocal signature of new physics, either induced by the QCD Theta-term or some beyond Standard Model mechanism.
I will present the most stringent limit on the neutron...
In this talk, I will explore consequences of the QCD θ-term in our Universe as well as in the Multiverse. First, I discuss the bounds set by element generation in the Big Bang on the value of θ. Then, I present precision results on various couplings of the axion to matter and also discuss a recent proposal of enhanced axiproduction via the ∆(1232) resonance.
We report our calculation of the neutron electric dipole moment (EDM) induced by the theta term. We use overlap fermions on three 2+1-flavor RBC/UKQCD domain wall lattices with pion mass ranging from ~300 to ~500 MeV. The use of lattice chiral fermions guarantees a correct chiral limit even at finite lattice spacings and enables us to reliably extrapolate our result from heavy pion masses to...
In this talk I will present a dynamical solution of the strong CP problem and discuss its consequences for the existence of a non-vanishing electric dipole moment of the neutron.
The Peccei-Quinn axion provides a simple solution to the strong-CP problem and is also a possible source of Dark Matter, being thus one of the most well-motivated extension of the Standard Model.
The simple relation between the axion mass and the QCD topological susceptibility allows, once the behavior of the latter quantity as a function of the temperature is known, to put useful bounds on...