Muon G-2 Experiment at Fermilab Finds Hint of New Particles • Hacker News Board

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#11

Post by libraryofbabel » Thu, Apr 08, 2021, 4:19 PM UTC

There have been a bunch of articles near the top of HN on this result, but I found this one from Quanta magazine to be one of the best non-technical explanations.

Particularly interesting was the focus on an alternative theoretical calculation for the muon magnetic moment: the “BMW” approach, which uses a numerical lattice model and produces a number much closer to the Fermilab experiment.

For an outsider, one of the surprising things here must be just how hard the theoretical calculation actually is, especially as you get deeper into the decimal places and have to include the vacuum effects on the muon of basically all particles in the standard model, including hadrons which means trying to calculate the Strong Force. Back when I studied quantum field theory in college we never got anywhere near actually producing numbers for strong force effects; the equations weren’t soluble with the usual perturbation theory techniques. But it’s interesting to read about how it is possible to get useful numbers with these different cutting-edge theoretical/computational methods - but with some uncertainty about whether they’re actually right!

Curious to hear any practicing physicists on HN weigh in on the BMW calculation versus the orthodox theoretical approach that everyone’s comparing the Fermilab result against.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#12

Post by vecter » Thu, Apr 08, 2021, 4:26 PM UTC

ganzuul wrote: post #7

mseepgood wrote: post #3

Why does it take physicists so long to find the complete foundation of the universe? I want an answer in my lifetime.

Hilbert's tomb: Wir müssen wissen Wir werden wissen You should not be downvoted. Spare the world a little cruelty where we can.

He/she is being downvoted for demanding an answer, as if they're entitled to one but all the physicists out there are just too dumb to figure it out or refuse to give them what they are owed.

Perhaps that is not how this person actually feels. If so, a little humility and empathy in their communication would go a long way to rectify that.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#13

Post by DrBazza » Thu, Apr 08, 2021, 4:33 PM UTC

Regardless of whether this is a real result, I always had trouble "trusting" the "Standard Model" when I was at university. There are too many knobs to twiddle, and levers to pull in order to get the results. The mathematics is non-trivial. Just reading the article gives you an idea of how difficult it is to make predictions from the model.

Compare it to this comment about General Relativity:

"Widely acknowledged as a theory of extraordinary beauty, general relativity has often been described as the most beautiful of all existing physical theories." (via wikipedia - Landau & Lifshitz 1975, p. 228).

(ignoring the cosmological constant, of course).

Compared to most, or all, other physical theories, the Standard Model feels like there's something much simpler set of equations underneath waiting to be discovered.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#14

Post by tobmlt » Thu, Apr 08, 2021, 4:33 PM UTC

libraryofbabel wrote: post #11

There have been a bunch of articles near the top of HN on this result, but I found this one from Quanta magazine to be one of the best non-technical explanations. Particularly interesting was the focus on an alternative theoretical calculation for the muon magnetic moment: the “BMW” approach, which uses a numerical lattice model and produces a number much closer to the Fermilab experiment. For an outsider, one of the…

Can’t upvote you enough. This is driving me crazy-curious. It must be eating at the HEP folks... unless it isn’t, hah.

If this becomes a quagmire nested with the muon quagmire within the new physics quagmire. I will surely have to find a way to renormalize my self energy.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#15

Post by xxpor » Thu, Apr 08, 2021, 4:34 PM UTC

mseepgood wrote: post #3

Why does it take physicists so long to find the complete foundation of the universe? I want an answer in my lifetime.

120 years ago, we had no model of the atom, no quantum theory, no relativity, and only the first hints of figuring out radioactivity. Yet we were able to split the atom in 1942, create the MOSFET in 1959, and started launching the first GPS satellites in 1978.

It's hard to express how much progress we've made in such a small amount of time relative to the rest of history. It's a god damn miracle.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#16

Post by ganzuul » Thu, Apr 08, 2021, 4:34 PM UTC

vecter wrote: post #12

ganzuul wrote: post #7

Earlier quoted context omitted.

Hilbert's tomb: Wir müssen wissen Wir werden wissen You should not be downvoted. Spare the world a little cruelty where we can.

He/she is being downvoted for demanding an answer, as if they're entitled to one but all the physicists out there are just too dumb to figure it out or refuse to give them what they are owed. Perhaps that is not how this person actually feels. If so, a little humility and empathy in their communication would go a long way to rectify that.

Hilbert demanded an answer too. Gödel showed that his effort would never reach its goal. We are all still reeling from the blow.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#17

Post by xxpor » Thu, Apr 08, 2021, 4:36 PM UTC

MichaelApproved wrote: post #9

mhh__ wrote: post #5

Earlier quoted context omitted.

So far we're struggling to reverse engineer all the perl it was hacked together with

I know you’re joking around but does the universe seem hacked together to you? I feel like it’s incredibly elegant. All these low level rules are able to create such complex structures with beautiful order to it. It’s so orderly, we can play things backwards billions of years. We can look back to how things were just a fraction of a second after this version of the universe began. It’s astonishing.

It's too bad we'll almost certainly never be able to answer the meta question of how or why we ended up with the rules we did.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#18

Post by whimsicalism » Thu, Apr 08, 2021, 4:41 PM UTC

DrBazza wrote: post #13

Regardless of whether this is a real result, I always had trouble "trusting" the "Standard Model" when I was at university. There are too many knobs to twiddle, and levers to pull in order to get the results. The mathematics is non-trivial. Just reading the article gives you an idea of how difficult it is to make predictions from the model. Compare it to this comment about General Relativity: "Widely acknowledged as…

It doesn't seem obvious that the fundamental models of reality would just happen to match up with the mathematical constructs that we humans have come up with.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#19

Post by whimsicalism » Thu, Apr 08, 2021, 4:43 PM UTC

xxpor wrote: post #17

MichaelApproved wrote: post #9

Earlier quoted context omitted.

I know you’re joking around but does the universe seem hacked together to you? I feel like it’s incredibly elegant. All these low level rules are able to create such complex structures with beautiful order to it. It’s so orderly, we can play things backwards billions of years. We can look back to how things were just a fraction of a second after this version of the universe began. It’s astonishing.

It's too bad we'll almost certainly never be able to answer the meta question of how or why we ended up with the rules we did.

These questions are more metaphysics than science.

I, personally, am partial to the idea that the anthropic principle has a pretty big role to play, at least in terms of the fundamental constants.

Re: Muon G-2 Experiment at Fermilab Finds Hint of New Particles

#20

Post by rrss » Thu, Apr 08, 2021, 4:45 PM UTC

ganzuul wrote: post #16

vecter wrote: post #12

Earlier quoted context omitted.

He/she is being downvoted for demanding an answer, as if they're entitled to one but all the physicists out there are just too dumb to figure it out or refuse to give them what they are owed. Perhaps that is not how this person actually feels. If so, a little humility and empathy in their communication would go a long way to rectify that.

Hilbert demanded an answer too. Gödel showed that his effort would never reach its goal. We are all still reeling from the blow.

The tomb next to hilbert:

"I must know. Why do the mathematicians take so long to find out?"