Speaker
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.
| What is your topic? | Hadronic decays |
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