# Frequency-splitting estimators for quark-line disconnected diagrams

#### Frequency-splitting estimators for quark-line disconnected diagrams

- Event time: 2:00pm
- Event date: 12th April 2019
- Speaker: Tim Harris (Università degli Studi di Milano Bicocca)
- Location: Room 4325A, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB

### Event details

In this talk I will present recent work on improved estimators for quark-line disconnected diagrams in lattice QCD.

The evaluation of these diagrams is required for many phenomenologically interesting observables, but suffers from large statistical errors due to vacuum contributions.

Multi-level integration schemes ameliorate such signal-to-noise ratio problems and have the potential to allow exponentially-improved precision in the computation of these observables.

To best exploit the multi-level for disconnected diagrams, the dominant noise due to auxiliary stochastic fields should be reduced below the gauge noise.

We have performed a theoretical analysis of the variances which has lead to new improved estimators, applicable with or without multi-level integration.

I will discuss the prospects of using such estimators in the context of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment.

### About Particle Physics Theory seminars

The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..