3 ms·

There's been plenty of significant discoveries, many, many. (O(10)s hadrons, consistent standard model discrepancies are really big news, those weren't expected

There's been plenty of significant discoveries, many, many. (O(10)s hadrons, consistent standard model discrepancies are really big news, those weren't expected) There hasn't been a significant new particle discovery, but none was expected other than Higgs, as far back as 2006 when I was still screwing around in graduate physics. I honestly can't remember the last time a new particle was randomly discovered by experiment that wasn't already proposed and agreed to as sound-in-theory. It's much cheaper and faster to do theory, then built what you need to verify, than to crank up energy as high as you can and hope for the best (I'd hazard a guess this ran out of steam by the 50s/60s at the latest)

T-A 2y ago
> There hasn't been a significant new particle discovery, but none was expected other than Higgs The word "expected" is doing a lot of work in that sentence. At least one kind of Higgs had to be found unless the mass generation mechanism of the Standard Model and all its proposed extensions (MSSM etc) was categorically wrong; the LHC was designed to cover the entire mass range where it had to be. In that sense, the Higgs was strictly expected. But if you had asked a bunch of phenomenologists "What new thing do you expect to be found first at the LHC?", most would have gone for one or more superpartners. The Higgs' hierarchy problem [1] was believed to require electroweak-scale SUSY, which in turn implied the existence of electroweak-scale supersymmetric partners to the known SM particles. Those would have been easier to find than the Higgs, so they would have shown up earlier in the data, before there was enough of it to also discern a Higgs bump. You could argue that superpartners were not expected with the same degree of certainty as some kind of Higgs, but the absence of any sign of SUSY was a big disappointment, and the beginning of the end for what had become the dominating scenario for Beyond Standard Model physics. [1] https://en.wikipedia.org/wiki/Hierarchy_problem#Supersymmetry https://en.wikipedia.org/wiki/Hierarchy_problem#Supersymmetr...
- MadnessASAP 2y ago
  I'm not much of a particles guy but isn't the lack of "expected" discoveries itself a discovery?
  - refulgentis 2y ago
    You nailed it. In addition, they're absolutely correct, some subset of particle researchers were wish-casting for SUSY stuff. In addition, there's a significant substantive difference between "$X was defined and built for discovering $Y" and "some subset of $X hoped for proof of their theory $Y via $Z being discovered" -- there was also some subset that hoped for proof of string theory, or innumerable other things. In general they're right and know their stuff if they're able to have this detailed of a take, but the actual claim "The word "expected" is doing a lot of work.", is doing a lot of work. And I was there. In a graduate physics lab with multiple faculty members on the LHC before it opened, including a big SUSY fan who thought that'd be a bank shot on a bank shot outcome, maybe. Hoped for by some? Yes. Expected by a majority? Absolutely not.
    - MadnessASAP 2y ago
      Neat! Thanks for sharing your insight and fancy words :)
    - T-A 2y ago
      Experimenters always were more skeptical; I hypothesized asking phenomenologists for a reason. I like Adam Falkowski's description of what it was like in [1] (about the end of dedicated SUSY working groups at CERN): the existence of SUSY was almost a fact for a bulk of researchers working on the topic. This certainly was reflected in hiring practices, and you had a large group of top researchers whose entire publication list was tied to supersymmetry [1] https://www.scientificamerican.com/article/supersymmetrys-long-fall-from-grace/ https://www.scientificamerican.com/article/supersymmetrys-lo...
      - refulgentis 2y ago
        I don't disagree but you choosing contrarianism to show you're clever and know a lot here (which worked!) made it sound like CERN was expecting a SUSY particle or whatever (which it wasn't)
        2y ago

T-A 2y ago

> There hasn't been a significant new particle discovery, but none was expected other than Higgs The word "expected" is doing a lot of work in that sentence. At least one kind of Higgs had to be found unless the mass generation mechanism of the Standard Model and all its proposed extensions (MSSM etc) was categorically wrong; the LHC was designed to cover the entire mass range where it had to be. In that sense, the Higgs was strictly expected. But if you had asked a bunch of phenomenologists "What new thing do you expect to be found first at the LHC?", most would have gone for one or more superpartners. The Higgs' hierarchy problem [1] was believed to require electroweak-scale SUSY, which in turn implied the existence of electroweak-scale supersymmetric partners to the known SM particles. Those would have been easier to find than the Higgs, so they would have shown up earlier in the data, before there was enough of it to also discern a Higgs bump. You could argue that superpartners were not expected with the same degree of certainty as some kind of Higgs, but the absence of any sign of SUSY was a big disappointment, and the beginning of the end for what had become the dominating scenario for Beyond Standard Model physics. [1] https://en.wikipedia.org/wiki/Hierarchy_problem#Supersymmetry https://en.wikipedia.org/wiki/Hierarchy_problem#Supersymmetr...

MadnessASAP 2y ago
I'm not much of a particles guy but isn't the lack of "expected" discoveries itself a discovery?
- refulgentis 2y ago
  You nailed it. In addition, they're absolutely correct, some subset of particle researchers were wish-casting for SUSY stuff. In addition, there's a significant substantive difference between "$X was defined and built for discovering $Y" and "some subset of $X hoped for proof of their theory $Y via $Z being discovered" -- there was also some subset that hoped for proof of string theory, or innumerable other things. In general they're right and know their stuff if they're able to have this detailed of a take, but the actual claim "The word "expected" is doing a lot of work.", is doing a lot of work. And I was there. In a graduate physics lab with multiple faculty members on the LHC before it opened, including a big SUSY fan who thought that'd be a bank shot on a bank shot outcome, maybe. Hoped for by some? Yes. Expected by a majority? Absolutely not.
  - MadnessASAP 2y ago
    Neat! Thanks for sharing your insight and fancy words :)
  - T-A 2y ago
    Experimenters always were more skeptical; I hypothesized asking phenomenologists for a reason. I like Adam Falkowski's description of what it was like in [1] (about the end of dedicated SUSY working groups at CERN): the existence of SUSY was almost a fact for a bulk of researchers working on the topic. This certainly was reflected in hiring practices, and you had a large group of top researchers whose entire publication list was tied to supersymmetry [1] https://www.scientificamerican.com/article/supersymmetrys-long-fall-from-grace/ https://www.scientificamerican.com/article/supersymmetrys-lo...
    - refulgentis 2y ago
      I don't disagree but you choosing contrarianism to show you're clever and know a lot here (which worked!) made it sound like CERN was expecting a SUSY particle or whatever (which it wasn't)
      - 2y ago