English

Updated determination of $\alpha_s(m_\tau^2)$ from tau decays

High Energy Physics - Phenomenology 2016-10-12 v1 High Energy Physics - Experiment

Abstract

Using the most recent release of the ALEPH τ\tau decay data, we present a very detailed phenomenological update of the αs(mτ2)\alpha_s(m_\tau^2) determination. We have exploited the sensitivity to the strong coupling in many different ways, exploring several complementary methodologies. All determinations turn out to be in excellent agreement, allowing us to extract a very reliable value of the strong coupling. We find αs(nf=3)(mτ2)=0.328±0.012\alpha_{s}^{(n_f=3)}(m_\tau^2) = 0.328 \pm 0.012 which implies αs(nf=5)(MZ2)=0.1197±0.0014\alpha_{s}^{(n_f=5)}(M_Z^{2}) = 0.1197\pm 0.0014. We critically revise previous work, and point out the problems flawing some recent analyses which claim slightly smaller values.

Keywords

Cite

@article{arxiv.1606.07764,
  title  = {Updated determination of $\alpha_s(m_\tau^2)$ from tau decays},
  author = {Antonio Pich and Antonio Rodríguez Sánchez},
  journal= {arXiv preprint arXiv:1606.07764},
  year   = {2016}
}

Comments

Invited contribution to the MITP workshop on Determination of the Fundamental Parameters in QCD (Mainz, 7-11 March 2016). 15 pages, 8 figures