Lattice QCD results for the topological up-quark mass contribution: too small to rescue the $m_u=0$ solution to the strong CP problem
| Autor: | Lena Funcke, Constantia Alexandrou, Jacob Finkenrath, Karl Jansen, Bartosz Kostrzewa, Ferenc Pittler, Carsten Urbach |
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| Rok vydání: | 2021 |
| Předmět: |
topological [mass]
Yukawa [coupling] High Energy Physics::Lattice FOS: Physical sciences conservation law: CP mass: twist nonperturbative symmetry: CP CP [strong interaction] quark High Energy Physics - Lattice High Energy Physics - Phenomenology (hep-ph) twist [mass] quantum chromodynamics ddc:530 fermion: mass: twist mass: topological lattice CP [conservation law] High Energy Physics::Phenomenology High Energy Physics - Lattice (hep-lat) CP [symmetry] lattice field theory up: coupling effect: topological coupling [up] High Energy Physics - Phenomenology mass: twist [fermion] current algebra instanton topological [effect] strong interaction: CP charm coupling: Yukawa |
| Zdroj: | Proceedings of Science / International School for Advanced Studies (LATTICE2021), 352 (2022). doi:10.22323/1.396.0352 38th International Symposium on Lattice Field Theory, Lattice 2021, Online, United States, 2021-07-26-2021-07-30 |
| DOI: | 10.48550/arxiv.2111.00288 |
| Popis: | 38th International Symposium on Lattice Field Theory, Lattice 2021, Online, United States, 26 Jul 2021 - 30 Jul 2021; Proceedings of Science / International School for Advanced Studies (LATTICE2021), 352 (2022). doi:10.22323/1.396.0352 A vanishing Yukawa coupling of the up quark could in principle solve the strong CP problem. To render this solution consistent with current algebra results, the up quark must receive an alternative mass contribution that conserves CP symmetry. Such a contribution could be provided by QCD through non-perturbative topological effects, including instantons. In this talk, we present the first direct lattice computation of this topological mass contribution, using gauge configurations generated by the Extended Twisted Mass collaboration. We use the Iwasaki gauge action, Wilson twisted mass fermions at maximal twist, and dynamical up, down, strange and charm quarks. Our result for the topological mass contribution is an order of magnitude too small to account for the phenomenologically required up-quark mass. This rules out the 'massless' up-quark solution to the strong CP problem, in accordance with previous results relying on $\chi$PT fits to lattice data. The talk is based on [Alexandrou et al., PRL 125, 232001 (2020)], where more details can be found. Published by SISSA, Trieste |
| Databáze: | OpenAIRE |
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