# What is new with Koide sum rules?

1. Mar 13, 2018

### arivero

Hmm, I should avoid to type from the phone. Well, anyway, the point was that perhaps GUT scale is not relevant for Koide. It is amusing that the main argument that we have (had?) for GUT is another numerical coincidence, the one of the coupling constants, but there was nothing about coincidence of yukawas... at most, variations on the theme of Jarslkog and Georgi https://en.wikipedia.org/wiki/Georgi–Jarlskog_mass_relation.

Another problem for quarks is that the pole mass is not directly measurable. Worse, Koide formula seems to work better with MSbar masses. Taking as input 4.18 and 1.28 GeV, Koide formula predicts 168.9 GeV for the top quark, while taking the pole masses 4.78 and 1.67 the prediction goes off to 203.2 GeV. (we nail it with intermediate mixes, eg input 4.18 and 1.37 predicts 173.3). Note that we now suspect that the MSbar mass of the top has a very noticeable EW contribution; Jegerlehner says that it actually counterweights the QCD contribution.

Last edited: Mar 13, 2018
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