# The 16th International Workshop on Tau Lepton Physics (TAU2021) (Virtual Edition)

September 27, 2021 to October 1, 2021
Indiana University
America/Indiana/Indianapolis timezone

## New results on the use of the operator product expansion in finite-energy sum rules for light-quark correlators

Sep 29, 2021, 11:40 AM
20m
Virtual (Indiana University)

### Virtual

#### Indiana University

Oral contribution Tau2021 Abstracts

### Speaker

Maarten Golterman (San Francisco State University)

### Description

Tau-based finite-energy sum rule (FESR) analyses often assume that scales
s_0~m_tau^2 are large enough that (i) integrated duality violations (DVs)
can be neglected, and (ii) contributions from non-perturbative OPE
condensates of dimension D scale as ~(Lambda_{QCD}/m_tau )^D, allowing the
OPE series to be truncated at low dimension. The latter assumption is not
true in general since the OPE series is not convergent, while the former
is open to question given experimental results for the electromagnetic,
I=1 vector (V), I=1 axial vector (A) and I=1 V+A current spectral functions,
which show clear DV oscillations with amplitudes comparable in size to the
corresponding alpha_s-dependent perturbative contributions at hadronic
invariant mass-squareds s~2-3 GeV^2. In this talk, we (1) introduce, and
illustrate the utility of, a new strategy for assessing the numerical
relevance of omitted higher-D OPE and/or residual DV contributions, (2) use
large N_c and analyticity arguments to derive the expected large-s form for
DV contribution to the I=1, V spectral function, under the assumption that
the leading behavior is Regge-like at large s, and (3) use this form to
explore the level of suppression of residual integrated DV contributions
in I=1, V channel FESRs.