interesting physics (2023 Update)

Did you read my original link? It seems that a pair of photons can collide and produce matter.

Sort of like a pair of particles colliding and making photons.

Of course, the smallest particle has a lot of mc^2 energy, so the photons would have to be very energetic.

I did. It seemed to involve colliding gold ions.

Jeroen Belleman

Ah now that is an insult, a clumsy one but you tried.

So according to your initial post it is "Brookhaven good, CERN bad", eh? Pathetic.

Cluck cluck. You have joined the village old biddies.

If I got it right it involved gold nuclei passing each other nearly at the speed of light thus producing enough EM field so the photons would have the energy it takes. A fine measurement.

I wonder if John knew they had done it at BNL and posted it because "BNL good CERN bad" you know :D. Or he just did not read that far and still "all colliders bad"....

Answer the question. Trying to be witty instead is just more pathetic. Or did you post the link without knowing how and where the experiment took place while waiting me to join your club.

I found the physics interesting, namely whether space is classical and linear. Both effects were predicted in theory decades ago.

Some people may think that the laws of the universe are regional. I don't. I sell to both BNL and to CERN.

You guys are such my-o-my old gossips. The physics doesn't care about your clucking.

So did you realize the link you were posting was about an experiment at BNL at the time of posting, yes or no please. We all know what the physics does not care about, clucking that sort of thing does not answer the questions I asked.

The other question was not to whom you sell, read it as many times as it takes.

While photons couple strongly with charged particles, photons are independent of matter - both exist, neither depending on the other for its existence.

As others have said, the experiment involved gold ions passing quite close to one another, but not actually colliding.

Joe Gwinn

I was wondering how did they do it - did they manage to make collisions unlikely enough (at that proximity... seems unlikely to me) or did they (likely) have both and just managed to measure what they were after.

I didn't pay much attention to where it was done. The photons don't care either.

What does it matter?

Of course it does not matter, the link was interesting. My initial question was with a smile, you got angry nonetheless and switched to insult mode - which is no big deal for me but my question "is it BNL good CERN bad" or is it "all colliders bad", based on our previous exchanges seemed amusing enough to me so I did not spare it to you. Was it so hard? Come on, give us a grin.

I would assume the latter, that they can tell the cases apart and ignore collisions. While I have not read the underlying data yet, it's hard to see how it could be done otherwise.

The bullets are gold nuclei, stripped of all electrons, and so are very strongly charged, and so will strongly repel one another. A direct collision will yield a shower of hadron et al debris. A very near miss will yield a large-angle deflection, but no debris.

Joe Gwinn

All I insulted was Big Money Physics.

;) or something?

I've been to SLAC, BNL, LLNL, NIF, LANL, Jlabs, Fermilab and designed a wire chamber system for CERN, but never went there. I don't think any of the big particle accelerators have returned much for their cost.

Since you want to see photons interacting in free space, without big physics, it's an example that involves fast gold ions, in a big-physics collider. That's why it matters.

Seeing a pair production without that impetus, is inconsistent with human lifespan.

My point is that you can't tell if you've got a photon until it has interacted with matter in a detector. Many would say that the photon had an independent existence before the interaction, but I adhere to the view that the photon *is* the interaction. Without interaction, there is no photon.

On these scales, the very concept of a 'collision' is vague. An ion is not a little solid clump of stuff. It has springiness, modes of vibration, rotation and it could even be said to be transparent. A 'collision' between two ions may result in anything from a mild deflection to a total destruction. Ions may end up vibrating or spinning after the interaction. Either way, this involves the exchange of photons and maybe other bosons beside. Again, a photon is merely the manifestation of an interaction. It has no independent existence.

Jeroen Belleman

He might have designed some of the electronics for a wire chamber system, which probably means that he was told exactly what the electronics had to do, with examples from other people's wire chambers. His "idea" of design seems to come close to doing what he was told to do, and documenting it.

John Larkin doesn't seem to think enough - he certainly doesn't know enough - to have a useful opinion. He certainly doesn't know enough to realise how uninteresting his opinions are.

While it's certainly true that we cannot detect any particle unless it blunders into something and changes it, it does not mean that such particles don't exist. Neutrinos are a classic example. And whatever Dark Matter turns out to be.

I suppose that for gravity waves there is no particle blundering into anything (instead we measure distortion of space), and yet gravity waves do exist.

This is certainly true.

The basic article is behind a paywall, so I don't know just how these issues are handled. Maybe there is an open pre-print somewhere.

But this is an assertion that may not follow from the above.

I fear we are falling into the "interpretations" swamp of quantum mechanics.

As many famous physicists have said, nobody understands QM, but it works spectacularly well, so just calculate and be happy.

Joe Gwinn

snipped-for-privacy@highlandsniptechnology.com wrote in news: snipped-for-privacy@4ax.com:

Sounds insulting to me. And you were the one pissing off about "cutting over to lame insults". You should watch what you dish for. And no that is not a typo.

Yeah and you ain't Steven Pinker.

That was the discussion before you got all personally analytical, and that down the wrong path.

Quite a lot. How many real scientists do you think are involved around the world with particle physics. It is a massive scalar boson. Science is a massive human undertaking. Has been throughout history.

Everything in life is one step at a time. Mothers spent hundreds or even thousands of years learning the intracies of child bearing and child rearing. All of those tid bits add up to our current knowledge. That is what humans do. We accumulate knowledge. Sometimes only one bit at a time, and some bits are very expensive to acquire, but we trudge on, nonetheless. You seem to be "sometheless". Always declaring that others are not discussing things or cannot or do not do what you can do. Does the side of your building have a big mural of you on it?

How much is anything which increases man's knowledge worth?

How do you even bean count the value of our endeavors?