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Particle mystery: physicists confirm the muon is more magnetic than predicted

sciencemag.org

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Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#62

Can anyone recommend any pop-sci books? I haven't taken a science class since high school, and that is barely remembered. Mostly interested in getting philosophically up to date with the state of matter(?), it's different types, how these objects interact.

My personal favorite:

- Thirty Years that Shook Physics: The Story of Quantum Theory

Other great books:

- The Theory Of Everything

- The Quark and the Jaguar

- Six Easy Pieces

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#63

Physics noob question: is there any physical framework that does away with the concept of "force"? I know a bit about how it is reconceptualized as space-time deformation in the context of general relativity, but that's about it. It just seems like one of those inherently anthropocentric concepts that (potentially) holds us back from exploring something different?

Gravity isn’t a force in general relativity.

However other forces such as the strong nuclear and the electroweak are forces in theories such as the standard model.

Grand Unification theories often are trying to turn gravity into a force this is where mediating particles such as the graviton come into play but these aren’t very successful yet.

It may be that gravity isn’t a force at all and is just an emergent phenomenon from the geometric properties of space time, or it could be both basically two distinct phenomena that cause attraction between massive objects where on a larger scale it’s primarily dominated by the geometry of space time and on the quantum scales by a mediated force with its own field and quanta (particles).

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#64

Honestly feel sorry for particle physicists... Their entire gig is spending billions on fancy equipment, and hoping that observe something unexpected. If they see exactly what they expected to see, all that effort was basically wasted. Also, a lot of "discoveries" turn out to be equipment miscalibration - remember those particles which supposedly moved faster than light a few years back? Always struck me as an odd wa…

Remember, you can't solve the halting problem. This is progress. Sometimes science takes two steps back and one step forward. Sometimes that one step is bigger than you realized. And it wasn't backwards, it was projecting into a different spacial dimension. Or something. The point is, this is probably good news, honestly.

Two steps back, but the new step forward is in better direction.

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#65

Physics noob question: is there any physical framework that does away with the concept of "force"? I know a bit about how it is reconceptualized as space-time deformation in the context of general relativity, but that's about it. It just seems like one of those inherently anthropocentric concepts that (potentially) holds us back from exploring something different?

Lagrangian mechanics is equivalent to Newtonian mechanics, but doesn't involve force https://en.wikipedia.org/wiki/Lagrangian_mechanics

The idea of replacing a 'gravitational force' with spacetime curvature gave us General Relativity; extending this same idea to electromagnetism gives us Kaluza-Klein theory https://en.wikipedia.org/wiki/Kaluza%E2%80%93Klein_theory

The current state of the art is Quantum Field Theory (of which the Standard Model is an example) https://en.wikipedia.org/wiki/Quantum_field_theory

In QFT, "particles" and "forces" are emergent phenomena (waves of excitation in the underlying fields, and the couplings/interactions/symmetries of those fields). QFT tends to be modelled using Lagrangian mechanics too.

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#66
post #46
post #32

Earlier quoted context omitted.

To clarify, for those not familiar with this topic, this experiment is making measurements at such exquisite precision that even the calculations for the theoretical prediction are extremely non-trivial and require careful estimation of many many pieces which are then combined. Which is to say that debugging the theoretical prediction is (almost) as hard as debugging the experiment. So I would expect the particle phy…

it's not good to cherry-pick paragraphs from the whole artile. > But as the Brookhaven team accrued 10 times more data, their measurement of the muon’s g-factor stayed the same while the error bars around the measurement shrank. The discrepancy with theory grew back to three sigma by the time of the experiment’s final report in 2006.

> it's not good to cherry-pick paragraphs from the whole artile

Isn't that exactly what you just did?

There's nothing wrong with showing only small quotes, the problem would be cherry picking them in a way that leads people to draw incorrect conclusions about the whole.

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#67

Earlier quoted context omitted.

From a physicists standpoint, not seeing something unexpected is not a waste at all.

Can you expand on that? I was under the impression that many thought of it as a waste (Sabine Hossenfelder comes to mind, for example).

Theorizing a phenomenon and having experimental evidence of a phenomenon are very different things.

Re: Particle mystery: physicists confirm the muon is more magnetic than predicted

#69
post #52

Physics noob question: is there any physical framework that does away with the concept of "force"? I know a bit about how it is reconceptualized as space-time deformation in the context of general relativity, but that's about it. It just seems like one of those inherently anthropocentric concepts that (potentially) holds us back from exploring something different?

Yes, very much so. Forces are not really a thing in the Standard Model. There are symmetry groups attached to spacetime which lead to exchanges of gauge bosons which 'create' forces.

Aren’t forces in the standard model just fields which their quanta is gauge bosons (force carrying particles)?
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