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Tuesday, February 6, 2024

A Higgs Boson Anomaly?

Scientists analyzing all available Higgs boson data from the Large Hadron Collider (LHC) observe a 2 sigma tension between the Standard Model prediction for the coupling of quarks and leptons to the Higgs boson and the observed values of those couplings, but see no tension between the predicted and observed couplings of W and Z bosons to the Higgs boson.

This isn't all that significant. Two sigma tensions disappear all the time with later more precise measurements. But it is something to be on the lookout for in future measurements of Higgs boson properties.
We perform global fits of the Higgs boson couplings to the full Higgs datasets collected at the LHC with the integrated luminosities per experiment of approximately 5/fb at 7 TeV, 20/fb at 8 TeV, and up to 139/fb at 13 TeV. Our combined analysis based on the experimental signal strengths used in this work and the theoretical ones elaborated for our analysis reliably reproduce the results in the literature. 
We reveal that the LHC Higgs precision data are no longer best described by the SM Higgs boson taking account of extensive and comprehensive CP-conserving and CP-violating scenarios found in several well-motivated models beyond the SM. Especially, in most of the fits considered in this work, we observe that the best-fitted values of the normalized Yukawa couplings are about 2σ below the corresponding SM ones with the 1σ errors of 3-5%. On the other hand, the gauge-Higgs couplings are consistent with the SM with the 1σ errors of 2-3%. Incidentally, the reduced Yukawa couplings help to explain the excess of the H→Zγ signal strength of 2.2±0.7 recently reported by the ATLAS and CMS collaborations.
Yongtae Heo, Dong-Won Jung, Jae Sik Lee, "Higgs Precision Analysis of the Full LHC Run 1 and Run 2 Data" arXiv:2402.02822 (February 5, 2024).

16 comments:

  1. Plan for Europe's huge new particle collider takes shape
    Europe's CERN laboratory revealed more details Monday about its plans for a huge new particle accelerator that would dwarf the Large Hadron Collider (LHC), ramping up efforts to uncover the underlying secrets of the universe.

    If approved, the Future Circular Collider (FCC) would start smashing its first particles together around the middle of this century—and start its highest-energy collisions around 2070.

    https://phys.org/news/2024-02-europe-huge-particle-collider.html


    Large Hadron Collider's $17-Billion Successor Moves Forward

    5 years new tunnel


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  2. do you or Mitchell Porter have opinions on

    Quantum Holonomy theory physicist Jesper Grimstrup and mathematician Johannes Aastrup

    https://www.youtube.com/watch?v=fSVbWwivu5g

    https://www.reddit.com/r/TheoreticalPhysics/comments/m8l1nt/introduction_to_quantum_holonomy_theory/

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  3. why's a "Complete waste of time"

    what about Alain Connes’ non-commutative geometry?

    or Alain Connes’ non-commutative geometry + loop quantum gravity

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  4. Maybe I'm wrong. Write to the authors and ask them if their theory can describe a hydrogen atom. Or a particle moving in space. And if they say yes it can, make sure they show you the equation

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  5. Blogger Mitchell said...

    Maybe I'm wrong. Write to the authors and ask them if their theory can describe a hydrogen atom. Or a particle moving in space. And if they say yes it can, make sure they show you the equation

    could string theory do this ?

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  6. Re FCC: I think a pause might not be a bad idea. HEP is stuck right now and a new more powerful collider without any clear target isn't a very efficient way to do science.

    "could string theory do this?"

    String theory has pretty much failed already.

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  7. @ andreww

    seems like it will get funding

    @Mitchell


    Quantum Holonomy theory is based on Alain Connes’ non-commutative geometry
    spectral triple

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  8. @neo

    "could string theory do this ?"

    String theory has umpteen different calculations of strings moving around in various kinds of spaces. It can also describe various kinds of bound states.

    To get the exact hydrogen atom of our world, would await a string theory vacuum that truly gives us the standard model with the measured values of its parameters.

    Aastrup and Grimstrup seem to say they can already directly couple the standard model fields to quantum gravity. I want to see that this is more than just writing an algebraic formula with no solution.

    If calculating something for the full standard model is too hard, then let them show that can perform calculations for something simpler, like a Klein-Gordon scalar coupled to quantum gravity. Or for anything.

    That's what I want, OK? Some evidence that their formalism is actually capable of dynamical predictions, even for a toy universe.

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  9. @Mitchell

    okay

    what about the earlier goal of Alain Connes’ non-commutative geometry
    spectral triple and Loop Quantum Gravity

    Intersecting Connes Noncommutative Geometry with Quantum Gravity Authors: Johannes Aastrup, Jesper M. Grimstrup (Submitted on 18 Jan 2006) Abstract: An intersection of Noncommutative Geometry and Loop Quantum Gravity is proposed. Alain Connes' Noncommutative Geometry provides a framework in which the Standard Model of particle physics coupled to general relativity is formulated as a unified, gravitational theory. However, to this day no quantization procedure compatible with this framework is known. In this paper we consider the noncommutative algebra of holonomy loops on a functional space of certain spin-connections. The construction of a spectral triple is outlined and ideas on interpretation and classical limit are presented.

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  10. You remember what Urs and I have said about LQG, right? It's a formalism that leads nowhere. Aastrup and Grimstrup looks the same. I told you the evidence I would need, in order to think otherwise.

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  11. okay
    what about Alain Connes’ non-commutative geometry
    spectral triple and Noncommutative standard model

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  12. is Alain Connes’ non-commutative geometry
    spectral triple and Noncommutative standard model credible ?

    how would you include quantum gravity in non-commutative geometry

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  13. Noncommutative standard model claims to obtain gauge fields, gravity, and the Higgs all at the same time, from the same construction. It seems odd to me that the Higgs could show up this way, I don't understand how the Higgs would obtain its specific gauge charges, but I might be missing something.

    Whether or not it works, the noncommutative standard model does not explain how the parameters of the standard model obtain their values - they are free parameters in the noncommutative framework too - so it doesn't look like a final theory. It's also not clear to me if the quantum gravity obtained this way is any improvement on ordinary perturbative quantum gravity.

    A number of papers have been written on introducing noncommutativity to Ashtekar gravity. I can't say if any of them are promising.

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  14. @Mitchell

    thanks

    Connes predicted mass of the Higgs 176gev was wrong

    gravity in non-commutative geometry is classical gr

    yes I have seen the number of papers have been written on introducing noncommutativity to Ashtekar gravity as well which is why I ask



    I wonder if you could combining noncommutativity to Ashtekar gravity to get the Noncommutative standard model with octonions and clifford algebra to get 3 generation of fermions with twisters in 4d with ads/cft

    ReplyDelete