Paper

{
  "raw_xml": "<entry>\n    <id>http://arxiv.org/abs/2603.02994v1</id>\n    <title>Kaon leptonic and semileptonic decays with $N_f=2+1+1$ HISQ fermions</title>\n    <updated>2026-03-03T13:46:15Z</updated>\n    <link href='https://arxiv.org/abs/2603.02994v1' rel='alternate' type='text/html'/>\n    <link href='https://arxiv.org/pdf/2603.02994v1' rel='related' title='pdf' type='application/pdf'/>\n    <summary>Precision tests of the Standard Model (SM) currently show a deficit in first-row Cabibbo-Kobayashi-Maskawa (CKM) unitarity. In this talk, we discuss progress towards a correlated analysis of the lattice-QCD inputs needed to test this relation with kaon data using highly improved staggered quarks (HISQ) on the MILC $N_{f}=2+1+1$ configurations. We present the status of a new analysis of light-meson decay constant data where chiral-continuum fits are guided by staggered chiral perturbation theory (SChPT). The goal of SChPT is twofold: it allows us to use data not only at physical pion mass but also at unphysical masses. Moreover, it provides values of ChPT low energy constants (LECs) as well as their correlations. We also present a reanalysis of our previous kaon semileptonic form factor calculation, aiming to estimate correlations between the form factor and light-meson decay constants. We discuss the new methodology, new data included, and present some preliminary results.</summary>\n    <category scheme='http://arxiv.org/schemas/atom' term='hep-lat'/>\n    <published>2026-03-03T13:46:15Z</published>\n    <arxiv:comment>10 pages, 5 figures. Proceedings of the 42nd International Symposium on Lattice Field Theory (Lattice 2025), TIFR Mumbai, India, 2025</arxiv:comment>\n    <arxiv:primary_category term='hep-lat'/>\n    <author>\n      <name>Ramón Merino</name>\n    </author>\n    <author>\n      <name>Alexei Bazavov</name>\n    </author>\n    <author>\n      <name>Claude W. Bernard</name>\n    </author>\n    <author>\n      <name>Carleton DeTar</name>\n    </author>\n    <author>\n      <name>Aida X. El-Khadra</name>\n    </author>\n    <author>\n      <name>Elvira Gámiz</name>\n    </author>\n    <author>\n      <name>Steven Gottlieb</name>\n    </author>\n    <author>\n      <name>Anthony V. Grebe</name>\n    </author>\n    <author>\n      <name>Urs M. Heller</name>\n    </author>\n    <author>\n      <name>Leon Hostetler</name>\n    </author>\n    <author>\n      <name>William I. Jay</name>\n    </author>\n    <author>\n      <name>Andreas S. Kronfeld</name>\n    </author>\n  </entry>"
}