Exploring flavor space of an economical SU(5) GUT in future proton decay measurements

We discuss the potential of future proton decay experiments on the exploration of the flavor space of grand unification. We focus on an eaconomical <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>S</a:mi><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mn>5</a:mn><a:mo stretchy="false">)</a:mo></a:math> grand unified model (GUT) with the fermion sector extended by including only one copy of 24-plet. Neutrino masses are generated via type-(<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mi mathvariant="normal">I</e:mi><e:mo>+</e:mo><e:mtext>III</e:mtext></e:mrow></e:math>) seesaw mechanism with the lightest neutrino massless. Gauge unification requires masses of fermions in the 24-plet to be hierarchical, in particular, the electroweak singlet and triplet heavy leptons to be around the canonical seesaw scale and TeV scale, respectively. We address how extra parameters in the flavor space which cannot be touched in flavor measurements can be tested by a multichannel analysis in future proton decay measurements. Published by the American Physical Society 2024