Recent content by mitchell porter

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    A Masses from modular symmetry

    It's not literally true, because of RG flow, as critics of the Koide formula like to remind us... They must mean is that the change between IR and UV is small enough, that mass ratios in the IR can still be a guide to the UV physics. (I'm not sure I'd agree, not for all masses, but it's the only...
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    B What's the distance metric for a compactified dimension?

    In more than four dimensions, the metric is written the same as in four dimensions, just with correspondingly more components. edit: I just noticed you're asking specifically about a compactified dimension... Well, once you have a compact space, the distance between points becomes...
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    The wrong turn of string theory: our world is SUSY at low energies

    One recurring theme in this thread, is the idea that the standard model might arise as the low energy limit of a theory which, at high energy, is a super-QCD (with quark superfields). I have run across a paper (and accompanying video) which studies a regime of SQCD which is promising from this...
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    A MOND theory primer

    That in formulating or judging a theory, one should bear in mind the main lines of evidence for dark matter and how dark matter accounts for them, and also the specific successes of MOND and how MOND accounts for those. The first step is because dark matter does more than account for galactic...
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    A MOND theory primer

    The astronomer Stacy McGaugh has become the most prominent public promoter of MOND (modified Newtonian dynamics) in recent years, on the grounds that it makes many successful predictions, yet according to the standard "LambdaCDM" (dark energy plus cold dark matter) paradigm, there's no reason it...
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    A New string formulae for Higgs mass and cosmological constant

    https://arxiv.org/abs/2106.04622 Calculating the Higgs Mass in String Theory Steven Abel, Keith R. Dienes [Submitted on 8 Jun 2021] There are at least two properties of the Higgs mass one might hope to explain with such a fundamental calculation: its criticality, and its participation in...
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    The wrong turn of string theory: our world is SUSY at low energies

    Koide's latest is a five-flavor preon theory! Although he only gets one generation at a time, and needs three further "family preons" to get three generations. And while some composite states are two flavor-preons plus a family preon, others are one flavor-preon plus two family-preons - whereas...
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    A The long awaited F theory book finally set out

    Not so strange if you think about it: "Applied data science": it's now common for people to use machine learning to search through sections of the string landscape for vacua of interest. Indeed, the author of the F-theory book himself now works as a data scientist. "Paper models": F-theory...
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    A Reviving Kaluza-Klein

    It's more that the "old" ideas are still far from completely explored. The apex of theoretical orthodoxy is that we are living somewhere in the landscape of solutions to string theory. This idea makes a great deal of sense, and actually brings more order to post-1970s theory than one had reason...
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    A Reviving Kaluza-Klein

    https://arxiv.org/abs/2105.02899 Higher-dimensional routes to the Standard Model bosons Joao Baptista [Submitted on 6 May 2021] https://arxiv.org/abs/2105.02901 Higher-dimensional routes to the Standard Model fermions Joao Baptista [Submitted on 6 May 2021]
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    It's a terrible thing. People understand the human tragedy of how her life ended, but I don't...

    It's a terrible thing. People understand the human tragedy of how her life ended, but I don't think they understand the intellectual loss. We've lost someone who had a unique and valuable place in the ecology of neo-minimalist theorists, and it's not even recognized.
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    A Just standard model and gravity, up to high energies? An update

    A recurring topic in particle physics, is the possibility of a "desert" above the electroweak scale: no new physics (new particles, new forces) until the grand unification scale or the Planck scale. It's important to remember that the Higgs boson mass was correctly predicted three years in...
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    Mass in motivic quantum gravity

    Marni Sheppeard, who posted here and in the physics blogosphere as @Kea, is believed dead. I think she was ahead of her time; we shall find out in the coming years.
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    A Octonions and the Standard Model

    Via @MTd2, I learned that a Perimeter Institute workshop on "Octonions and the Standard Model" has taken place in February. In the final slide of his presentation, Kirill Krasnov foreshadowed a paper that appeared this week, "Spin(11,3), particles and octonions". This is a version of the old...
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    I M-theory and Calabi-Yau compactifications

    I got confused about the isometry groups for a moment... @bayakiv is embedding one object in another and looking at the isometries of the combined object, I will discuss that in a moment. Normally (in Kaluza-Klein), one looks for a single compact manifold whose complete group of isometries is...
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