Andreas Athenodorou - Welcome Room: Aula Leonardi

The nEDM @ Spallation Neutron Source experiment: our novel approach and other physics reach

• Kent Leung (Montclair State University)

Room: Aula Leonardi

Theta Dependence of QCD and QCD-like Theories

• Massimo D' Elia (University of Pisa)

Room: Aula Leonardi

Neutron electric dipole moment using lattice QCD

• Constantia Alexandrou (University of Cyprus)

Room: Remotely 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 we employ a fermionic definition by means of spectral projectors. We find a value of |𝑑⃗𝑁|=0.0009(24) 𝜃 𝑒⋅fm.

The LANL nEDM Experiment

• Takeyasu Ito (Los Alamos National Laboratory)

Room: Remotely

Cosmological implications of the Neutron Electric Dipole Moment

• Laura Covi (Georg-August-Universität Göttingen)

Room: Aula Leonardi

Topology in SU(N) gauge theories

• Michael Teper (University of Oxford)

Room: Remotely

Cluster decomposition, the index theorem, and the strong CP problem

• Carlos Tamarit (Technische Universität München)

Room: Aula Leonardi

EDMs and Baryogenesis

• Michael Ramsey-Musolf (University of Massachusetts)

Room: Remotely

The most stringent limit on the nEDM and future improvements at PSI

• Philipp Schmidt-Wellenburg (Paul Scherrer Institute)

Room: Aula Leonardi 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 EDM, |d_n |<1.8×10^(-26) ecm [4], from an experiment performed at the Paul Scherrer Institute by an international collaboration deploying Ramsey’s method of separated oscillating magnetic fields on stored ultra cold neutrons. I will motivate and discuss the most salient feature of the experiment, a 199Hg co-magnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic field changes. In a second part, I will present the design of the new instrument, n2EDM, currently mounted at PSI, which will further increase the sensitivity to about 1×10^(-27) ecm [5]. References [1] A.D. Sakharov. JETP Lett. 5, 24(1967) [2] C.L. Bennett, D. Larson, J. L. Weiland, et al., ApJS 208, 20 (2013) [3] D.E. Morrissey and M.J. Ramsey-Musolf, New J. Phys. 14, 125003 (2012) [4] C. Abel et al., PRL124, 081803 (2020) [5] N.J. Ayres et al., EPJC81, 512 (2021)

BeamEDM – A beam experiment to search for the neutron electric dipole moment

• Florian Piegsa (University of Bern)

Room: Aula Leonardi

Fermion correlations and absence of CP violation in the strong interactions

• Bjorn Garbrecht (Technical University Munich)

Room: Aula Leonardi

Calculation of neutron EDMs on the lattice

• Boram Yoon (Los Alamos National Laboratory)

Room: Remotely

Aspects of strong CP violation

• Ulf Meißner (University of Bonn)

Room: Aula Leonardi 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.

Estimating CP-violating nucleon matrix elements from CP-conserving ones

• Andre Walker-Loud (Lawrence Berkeley National Laboratory)

Room: Aula Leonardi

Neutron Electric Dipole Moment from the Theta Term with Overlap Fermions

• Keh-Fei Liu (University of Kentucky)

Room: Aula Leonardi 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 the physical point. Furthermore, by utilizing the partially-quenched chiral extrapolation formula, several valence pion points are added to better constrain the chiral extrapolation. With the help of the cluster decomposition error reduction (CDER) technique and a large amount of statistics accumulated, the statistical uncertainty is effectively controlled. We also carefully check the systematic uncertainties from the two-state fits, the momentum extrapolation, the chiral extrapolation and the CDER technique.

Neutron electric dipole moment from QCD?

• Gerrit Schierholz (DESY)

Room: Remotely 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.

Disentangling physics beyond the Standard Model with EDMs

• Emanuele Mereghetti (Los Alamos National Laboratory)

Room: Aula Leonardi

QCD Theta term contribution to nEDM with Stabilized Wilson Fermion on the lattice

• Jangho Kim (Forschungszentrum Juelich)

Room: Aula Leonardi

Updates on the PanEDM experiment and future outlook

• Skyler Degenkolb (Universität Heidelberg)

Room: Remotely

The Peccei-Quinn axion and QCD topology

• Claudio Bonanno (INFN Sezione di Firenze)

Room: Aula Leonardi 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 the axion scale through the misalignment mechanism, which in principle could also be probed by forthcoming experiments such as IAXO. The numerical non-perturbative computation of the temperature-behavior of the QCD topological susceptibility from lattice simulations is however an highly non-trivial task, being it plagued by serious computational problems, and many different strategies to overcome them have been proposed in the recent literature to this end. In this talk, after reviewing the main physical aspects of axion physics and of QCD topology, I will give an overview about the current status of lattice determinations of the QCD topological susceptibility at high temperatures and I will discuss possible future research directions.