Is supersymmetry dead?

[wolram]

Super symmetry has lasted a long time and has been searched for with bigger and bigger colliders,
And the particles seem to get more and more massive as time goes by, I'm no expert but it seems unlikely
That thees super heavy particles exist.

https://www.forbes.com/sites/starts...hysics-that-need-to-die-already/#b263f3257b7f

 

[lekh2003]

Super symmetry has lasted a long time and has been searched for with bigger and bigger colliders,
And the particles seem to get more and more massive as time goes by, I'm no expert but it seems unlikely
That thees super heavy particles exist.

https://www.forbes.com/sites/starts...hysics-that-need-to-die-already/#b263f3257b7f

Quite the opposite. Super-symmetry is a plausible theory. The problem is that we do not have the resources to find this particles. Massive amounts of energy are required and we don't have it.

Just because we can't see it doesn't mean it might not be there.

 

[haushofer]

Quite the opposite. Super-symmetry is a plausible theory. The problem is that we do not have the resources to find this particles. Massive amounts of energy are required and we don't have it.

Just because we can't see it doesn't mean it might not be there.

Well, no, but the same goes for faries and goblins.

The plausability of SUSY depends heavily on theoretical argument of which we know they served us very well in the past. But the lack of experimental findings should make you doubt the validity of these lessons from the past.

 

[lekh2003]

Well, no, but the same goes for faries and goblins.

The plausability of SUSY depends heavily on theoretical argument of which we know they served us very well in the past. But the lack of experimental findings should make you doubt the validity of these lessons from the past.

That's an interesting approach, but that's the beauty of a theory. It is perfectly correct until proven wrong.

 

[wolram]

It makes me wonder if supersymmetry is a valid theory now, surly there can not be particles with this mass, I just read this http://www.theworldin.com/article/12781/so-long-susy?fsrc=scn/tw/wi/bl/ed/ and it seems to re enforce my limited understanding of the subject.

 

[MathematicalPhysicist]

Nothing really dies, you'll find reincarnations of this and that in every new theory.

My problem is with the notion of "particles", every theory suggest new particles, does that mean there are infinite number of particles?
Does that mean that as you partition space you'll find more and more particles?

I mean in the far future I can see even greater particles' colliders, heck some may say the universe began as such an experiment (big bang).
(Obviously as I believe there's no beginning, it's just another experiment).

 

[bapowell]

That's an interesting approach, but that's the beauty of a theory. It is perfectly correct until proven wrong.

Perfectly correct? No, it's just "not wrong".

 

[haushofer]

That's an interesting approach, but that's the beauty of a theory. It is perfectly correct until proven wrong.

In which sense? Mathematically or correct as in "describes our reality"?

 

[lekh2003]

Perfectly correct? No, it's just "not wrong".

Once an idea has the status of being "not wrong", it is called a theory. A theory is a theory and just that, not a fixed idea, which is called a law.

Super symmetry physicists have not called super symmetry a law but a theory. They are entitled to a theory. And it could be wrong but that's because its a theory.

 

[bapowell]

Once an idea has the status of being "not wrong", it is called a theory. A theory is a theory and just that, not a fixed idea, which is called a law.

This is not what a theory is. This is a "theory" the way creationists dismiss evolution as "just a theory", as in, just a proposed, hypothetical, untested set of ideas. No, a scientific theory is a rigorously-tested collection of ideas, well-supported by evidence. (see https://www.scientificamerican.com/article/just-a-theory-7-misused-science-words/)

 

[lekh2003]

This is not what a theory is. This is a "theory" the way creationists dismiss evolution as "just a theory", as in, just a proposed, hypothetical, untested set of ideas. No, a scientific theory is a rigorously-tested collection of ideas, well-supported by evidence. (see https://www.scientificamerican.com/article/just-a-theory-7-misused-science-words/)

Ok, I guess we can then say the validity of supersymmetry is dependent on how you treat the evidence.

 

[bapowell]

Ok, I guess we can then say the validity of supersymmetry is dependent on how you treat the evidence.

Yes. As with any scientific proposal, its success depends on how well it squares with the evidence.

 

[PAllen]

I would say supersymmetry is an attractive hypothesis, not a theory at all. Similarly for all BSM and quantum gravity proposals. Of course, attractiveness is in the eye of the beholder. To me, supersymmetry proposal is attractive. Over time, the tense of the last sentence’s verb may change, if evidence fails to materialize.

I don’t think the picture has changed much from the following honest review by someone who finds the proposal attractive:

https://arxiv.org/abs/1309.0528

[edit: I add the following link for no other reason than its title:

https://arxiv.org/abs/1106.2164
]

 

[Urs Schreiber]

There was never any theory with deeper motivation that predicted the low-energy supersymmetry that is being highly constrained by LHC data. Even though, after a few decades, people behaved as if there is something in string theory that picks CY compactifications that yield low energy supersymmetry in the effective 4d-theory, in fact there is no such mechanism known in the theory.

There is one theory which predicts high energy supersymmetry: Namely it is a theorem that 1) assuming that particles are string excitations and 2) the existence of fermions in the string spectrum implies high-energy local target space supersymmetry, aka supergravity (which is different from the low energy supersymmetry constrained by LHC data). E.g. Duff: "The status of local supersymmetry" (hep-th/0403160).

Of course this does not imply that local/high energy supersymmetry is realized in nature, but it is good to be aware of the difference. There is a faint bit of preference for high energy supersymmetry from the Planck data: according to this.

 

[PAllen]

There was never any theory with deeper motivation that predicted the low-energy supersymmetry that is being highly constrained by LHC data. Even though, after a few decades, people behaved as if there is something in string theory that picks CY compactifications that yield low energy supersymmetry in the effective 4d-theory, in fact there is no such mechanism known in the theory.

There is one theory which predicts high energy supersymmetry: Namely it is a theorem that 1) assuming that particles are string excitations and 2) the existence of fermions in the string spectrum implies high-energy local target space supersymmetry, aka supergravity (which is different from the low energy supersymmetry constrained by LHC data). E.g. Duff: "The status of local supersymmetry" (hep-th/0403160).

Of course this does not imply that local/high energy supersymmetry is realized in nature, but it is good to be aware of the difference. There is a faint bit of preference for high energy supersymmetry from the Planck data: according to this.

Can you get very high energy supersymmetry to help with the hierarchy problem and provide plausible candidate particles for dark matter?

 

[rootone]

Well, no, but the same goes for faries and goblins.

... and, in my opinion, multiverse nonsense as well.

 

[haushofer]

... and, in my opinion, multiverse nonsense as well.

Well, this is not the topic to discuss the multiverse, but the plausibility of scientific hypotheses is of course not the same as hypotheses from fantasy novels.

And yes, the multiverse is science, whether it makes you feel uncomfortable or not.

 

[MathematicalPhysicist]

Well, this is not the topic to discuss the multiverse, but the plausibility of scientific hypotheses is of course not the same as hypotheses from fantasy novels.

And yes, the multiverse is science, whether it makes you feel uncomfortable or not.

And in other universes, fairies and goblins may be a reality... :->

 

[haushofer]

And in other universes, fairies and goblins may be a reality... :->

If they are solutions to the underlying equations :P

 

[MathematicalPhysicist]

If they are solutions to the underlying equations :P

What are the equations which their solutions dictate our existence?

 

[Haelfix]

Can you get very high energy supersymmetry to help with the hierarchy problem and provide plausible candidate particles for dark matter?

Not that I know off for the first. Yes for the second. High scale supersymmetry has interesting phenomenology. It helps with Leptogenesis, as well as inflationary and GUT scale model building. However the dark matter candidate (the LSP with R parity) must necessarily be relatively light to avoid overproduction in the early universe and so there will be a large hierarchy between that mass and the natural mass of the other superpartners. Scenarios like that have been explored quite a bit recently. Alternatively you also have models with mid scale supersymmetry (with superpartners at around the 100s or 1000s of TEV) and these naturally also provide a dark matter candidate without finetuning (the mass of the Higgs of course will be tuned at the 10^5-10^6 level). That's called split supersymmetry.

 

[TheOldFart]

... and, in my opinion, multiverse nonsense as well.

Except the multiverse isn't a theory, it's a consequence of some theories, right?

 

[haushofer]

What are the equations which their solutions dictate our existence?

I've developed an effective field theory which, as solutions, has humans. But I haven't published it yet, since I only obtain women, not men, due to a lack of spontaneous gendersymmetrybreaking.

It also contains cats, so I can also explain half of the youtube content with it. :P

 

And in other universes, fairies and goblins may be a reality... :->

Even if fairies and globlins were reality in other multi universe.. their scientists may still not be able to detect them if they have the same mindset as our scientists which are:

1. Expecting the fairies and goblins and ghosts to knock on their doors
2. Only accepting doing experiments that conform to their preconceived ideas of how nature works...and if there are massive null results.. using arguments of Unnaturalness akin to Sabine who critiqued other physicists.. but just the same, she suffered the same bias of accepting only experiments that conform to the preconceived ideas of how nature works
3. Refusing to consider the possibility consciousness or sentience can develop in subtle matter such as dark matter
4. Refusing to do experiments where these sentient beings were invoked or call upon.. or doing any experiments that involves more complexities like accessing certain information contents to cause a physical shift or result... in addition to just colliding particles like in particle accelerators
4. Promoting Shut Up and Calculate in QM and QFT and ignoring any possible ontology (which may have new degree of freedom showing up) with the results one throws the baby with the bathwater
5. Treating all witnesses to them as mentally unstable.. including witnesses to giant dark matter entities known as UFOs.. They can't consider the possibility that just like living things can come in all sizes from dinosaurs to mosquities.. so can these entities.. and for those among them like the recent Pentagon official at CNN.. who acknowledge they perform feat not possible in aerodynamics.. and falsely attributing it to alien presence when dark matter entities can produce the same trick.

So for these other universe scientists to detect them.. they need reeducation if they think like us.. lol...
Hey, it's year end yuletide vacation period and time to relax the mind and accept some humor to release the tension and stress throughout the year. Merry Christmas everyone! :)

 

[websterling]

And in other universes, fairies and goblins may be a reality... :->

I would think that in a multiverse composed of a near infinite number of universes, that in some of those universes fairies and/or goblins would be required

if fairies and globlins were reality in other multi universe.. their scientists may still not be able to detect them

And that in some of those universes fairies and goblins would be the scientists.

fairies and globlins

And even some globlins!

 

I would think that in a multiverse composed of a near infinite number of universes, that in some of those universes fairies and/or goblins would be required



And that in some of those universes fairies and goblins would be the scientists.

You were assuming fresh and blood fairies and goblins in other "multiverse"? Even in physics.. we need to use the right definition to avoid confusion.. in our universe.. "fairies" and "goblins" are words to reserve creatures that are anything but flesh and blood. In my country, we mostly have so much reports of bad goblins possessing school children. This occurs elsewhere in other parts of the world too:

https://www.dailystar.co.uk/news/la...ession-priest-goblin-woman-scream-philippines

All right. You may think they are all simply deluded as this is what our physics can give us at this point in time. But note of this. Even if they are delusions, "fairies" and "goblins' were not flesh and blood in our universe. So we mustn't use the terms to refer to them as scientists in other multiverses.

This is just to illustrate semantics is important when comparisons are made or this or other multiverses (therefore this post is to clarify semantics and I'm not violating any forum rule).

Speaking of multiverses. What are good books related to string landscapes and multiverses, are they same? how do they differ?

To be scientific. Let's avoid talking about the fairies and golbins and narrow it down to multiverses and high scale supersymmetry. If there were high scale supersymmetry.. does it mean supersymmetry is still not dead?

And even some globlins!

 

[gdixon]

Every failure to find evidence is viewed optimistically,
giving rise to a clamor for more funding and higher
energies. It was never a beautiful idea; not even pretty.
Like GUTs, it arose out of nothing more fundamental
than a desire to extend an idea (standard symmetry
gauge groups) that was at the time novel, and giving
rise to multiple Nobel prizes. As a graduate student
I was pushed very hard to commit to SUSY. I saw
absolutely nothing elegant or beautiful in the idea,
so in the end disappointed my mentors by looking
elsewhere for Dirac’s mathematical beauty.

Want to assess its value accurately? Take a vote, but
take each yes vote and divide by some measure of how
much that person’s funding and reputation will be hurt
if it fails (and how many fruitless years (nay, decades)
they’ve committed to the idea).

 

[Quotidian]

I am not well educated in physics, but read articles about it in the popular press, New Scientist and the like. It seems that there has been no confirmation of the so-called SUSY model by the LHC since the announcement of the discovery of the Higgs Boson (although I note above that some say it's still 'out there' but we don't have/will never have enough power to detect it).

But at least some are saying that the model should be abandoned. So the question I have is this. SUSY was originally devised to solve a whole set of issues in fundamental physics, and apparently did so in a mathematically elegant manner. But if SUSY is regarded as being disconfirmed, then the issues that SUSY was supposed to be the solution for, remain as outstanding problems. What kinds of problems are they?

 

[Urs Schreiber]

Can you get very high energy supersymmetry to [...] provide plausible candidate particles for dark matter?

Yes, supergravity KK-models predict axions (the "B-field") generically. While standard cold WIMP dark matter models work excellently on cosmological scales, they have severe problems on galactic scales (whence "MOND"). But ultralight axions are getting much attention these days (under various names, such as BEC/superfluid/fuzzy dark matter ) since they would naturally explain a phase shift of behaviour that dark matter (if any) needs to exhibit at around the scale of galaxies.

See Hui-Tremaine-Ostriker-Witten 16 between equations (3) and (5).

 

[Martin0001]

Nothing new up to 10^16 GeV, maybe up to 10^19 GeV. So new physics might be there but under event horizons.
OK, we are not building any particle accelelators size of Solar System (to get 10^16 GeV) or hundreds of light years across to get 10^19 GeV anytime soon.
Boys, time to pack your toys and go home on dinner. Mama is calling. Nothing to see here.

 

[bluecap]

Nothing new up to 10^16 GeV, maybe up to 10^19 GeV. So new physics might be there but under event horizons.
OK, we are not building any particle accelelators size of Solar System (to get 10^16 GeV) or hundreds of light years across to get 10^19 GeV anytime soon.
Boys, time to pack your toys and go home on dinner. Mama is calling. Nothing to see here.

In 1 Billion A.D. Can we already reach 10^16 GeV or say 3 Billion A.D.? How many billions of years later before we can probe the Planck scale?

Anyway. A hundred years from now.. when building more accelerators would no longer be viable due to financial, environment, political or military catastrophe. Can we at least do one last experiment never before tried (at least officially)...

There may be a Particle Desert where nothing occurs below 10^16 GeV and above those already explored. So let the last final experiment be about testing non-thermal based symmetry breaking. Perhaps all those missing particles would suddenly popping up. In many unofficial experiments now. They detected exotic particles even monopoles by initiating non-thermal phase transition but no other scientists want to even try duplicating any of it. So before we dismantle the last particle accelerator on Earth and before the last particle physicists get into other fields like banking or telecommunications industry.. can we at least try this one last experiment? Perhaps we would see results the world has never seen before..

 

[Urs Schreiber]

Interesting to read Gordon Kane, who keeps going all in with yesterday's

Exciting implications of LHC Higgs Boson Data
(arXiv:1802.05199)

The content is not entirely new, in itself it seems to be a (somewhat hasty) writeup of a talk given already in January 2017 on occasion of Kane receiving the Sakurai prize 2017 "For instrumental contributions to the theory of the properties, reactions, and signatures of the Higgs boson."

The prize announcement knows that "Dr. Kane made important early contributions to the study of the Higgs Bosons, including an upper limit on the Higgs boson mass..." (this refers to his bold claim of a Higgs mass prediction via the $G_2$-MSSM in Kane 11, a useful informed comment is here), "...to the study of dark matter and its detection and to string theory phenomenology. His more recent work has been in the development of testable models based on string theory, in particular those based on $G_2$ compactifications of M-theory, a predictive approach that explains the hierarchy between the weak scale and the Planck scale. Dr. Kane has argued that these ideas form a consistent framework with a non-thermal cosmological history of the universe."

The article discusses four "clues" obtained from the LHC data and argued to be clues for the presence of low-scale supersymmetry. The third clue claims that some model of low scale susy is still consistent with observation, the first clue recalls that the observed Higgs mass is close to the upper limit constrained by low-scale susy, while the fourth clue claims that the observed Higgs potential is inconsistent without low-scale susy, which would cure the apparent vacuum instability.

I suppose that whether or not low-scale susy is the answer, there is a point to be made, re the fourth clue, that the apparent vacuum instability of the experimentally observed Higgs potential is in contrast to the often heard claim that "nothing new or interesting" for HEP has come out of the observation of the Higgs at LHC.

 

[bluecap]

Interesting to read Gordon Kane, who keeps going all in with yesterday's

Exciting implications of LHC Higgs Boson Data
(arXiv:1802.05199)

The content is not entirely new, in itself it seems to be a (somewhat hasty) writeup of a talk given already in January 2017 on occasion of Kane receiving the Sakurai prize 2017 "For instrumental contributions to the theory of the properties, reactions, and signatures of the Higgs boson."

The prize announcement knows that "Dr. Kane made important early contributions to the study of the Higgs Bosons, including an upper limit on the Higgs boson mass..." (this refers to his bold claim of a Higgs mass prediction via the $G_2$-MSSM in Kane 11, a useful informed comment is here), "...to the study of dark matter and its detection and to string theory phenomenology. His more recent work has been in the development of testable models based on string theory, in particular those based on $G_2$ compactifications of M-theory, a predictive approach that explains the hierarchy between the weak scale and the Planck scale. Dr. Kane has argued that these ideas form a consistent framework with a non-thermal cosmological history of the universe."

The article discusses four "clues" obtained from the LHC data and argued to be clues for the presence of low-scale supersymmetry. The third clue claims that some model of low scale susy is still consistent with observation, the first clue recalls that the observed Higgs mass is close to the upper limit constrained by low-scale susy, while the fourth clue claims that the observed Higgs potential is inconsistent without low-scale susy, which would cure the apparent vacuum instability.

I suppose that whether or not low-scale susy is the answer, there is a point to be made, re the fourth clue, that the apparent vacuum instability of the experimentally observed Higgs potential is in contrast to the often heard claim that "nothing new or interesting" for HEP has come out of the observation of the Higgs at LHC.

Very hopeful and encouraging.
Just a question Urs. Is there no existing work or papers about non-thermal symmetry breaking or phase transition whether in the quantum fields, quantum vacuum, spacetime or other stuff? If there is. What is the technical words used for non-thermal symmetry breaking. To illustrate the point. For the electroweak. We need very high temperature to put the symmetry back into place just like what we are doing at particle accelerating by colliding particles and reproducing the high temperature. Is there any concept where you can put the symmetry back into place for other particles by non-thermal means? If none. Why is it not possible?

 

[Urs Schreiber]

Very hopeful and encouraging.

By the way, the text has a bit of overlap with that of his book

• Gordon Kane,
  "String theory and the real world",
  Morgan & Claypool, 2017
  (doi:0.1088/978-1-6817-4489-6)

where it corresponds to sections 5.1 and 6.4.

Is there no existing work or papers about non-thermal symmetry breaking

Hm, it seems to me that the bulk of the literature is about supersymmetry breaking in non-thermal contexts. A few authors discuss thermal supersymmetry breaking, for brief exposition see for instance

• Claudio Lucchesi,
  "Symmetries at finite temperature"
  in F. Gieres et. al (eds.)
  "Symmetries in physics"
  Edition Frontieres (1997)

There is maybe some care advised regarding the difference between invoking high tempterature to argue that a system has high energy and having a genuinely thermal description, usually referred to as "QFT at finite temperature". The latter requires more work and is considered by fewer authors.

 

[bluecap]

By the way, the text has a bit of overlap with that of his book

• Gordon Kane,
  "String theory and the real world",
  Morgan & Claypool, 2017
  (doi:0.1088/978-1-6817-4489-6)

where it corresponds to sections 5.1 and 6.4.



Hm, it seems to me that the bulk of the literature is about supersymmetry breaking in non-thermal contexts. A few authors discuss thermal supersymmetry breaking, for brief exposition see for instance

• Claudio Lucchesi,
  "Symmetries at finite temperature"
  in F. Gieres et. al (eds.)
  "Symmetries in physics"
  Edition Frontieres (1997)

There is maybe some care advised regarding the difference between invoking high tempterature to argue that a system has high energy and having a genuinely thermal description, usually referred to as "QFT at finite temperature". The latter requires more work and is considered by fewer authors.

I was asking whether you can have a new gauge-like field or fundamental force (not electroweak or strong) that has similar symmetry breaking as SUSY breaking not dependent on spontaneous symmetry breaking (or Big Bang scale gauge fields) but could be for instance gravity or anomaly mediated (as applied to SUSY symmtry breaking see https://arxiv.org/pdf/hep-th/0601076.pdf) ... or in other words, are soft gauge-like forces possible also by some SUSY-like vacua dynamics?

I'm aware of the difference between gauge and susy symmetry breaking from http://people.sissa.it/~bertmat/lect7.pdf

Can you design a fundamental force of nature that has same symmetry breaking mechanism as proposed for SUSY and can initiate symmetry breaking far below the weak scale or even low energy?