B LHC findings -- 'Naturalness' and Many Worlds

[Quotidian]

In December 2015, scientists at the Large Hadron Collider (LHC) thought they may have seen a hint of a brand-new particle. This appeared by way of a couple of 'bumps' in the data, which triggered such an avalanche of interest that 500 papers followed. But, alas, subsequent research has shown that there really was no such particle:

'"The bad news is [the measurements] don't show anything," said theoretical physicist Matt Strassler. "The good news is that it did a really good job of not showing anything."

From here.

There's a good analysis on The Atlantic Monthly called Back to the Drawing Board which goes into some of the philosophical implications of this non-discovery. In brief, the story is as follows: whilst the discovery of the God Particle, er, Higgs Boson, was a triumph, it might also signal, according to some, the 'end of the road' for particle physics (I think this is the 'nightmare scenario'). It confirms many major aspects of the 'standard model', but the problem with that model is its 'unnaturalness'. There are many things about it which are 'just so', but for which there doesn't appear to be any explanation:

Aside from having a large number of different particles and forces, many of which seem surplus to requirement, [the Standard Model] is also very precariously balanced. If you change any of the 20+ numbers that have to be put into the theory even a little, you rapidly find yourself living in a universe without atoms. This spooky fine-tuning worries many physicists, leaving the universe looking as though it has been set up in just the right way for life to exist.

Harry Cliff
from here.

It was hoped that 'supersymmetry' might provide a deeper level of explanation, a 'why is it so', that would account for the spooky just-so-ness of the Higgs, among other things - but nothing has turned up; the excitement about the bump-that-dissappeared was that this might have been one such discovery. But no - and many are saying that it might be over for supersymmetry (hence the title of the Atlantic article).

The Atlantic likewise comments:

Many particle theorists now acknowledge a long-looming possibility: that the mass of the Higgs boson is simply unnatural—its small value resulting from an accidental, fine-tuned cancellation in a cosmic game of tug-of-war—and that we observe such a peculiar property because our lives depend on it. In this scenario, there are many, many universes, each shaped by different chance combinations of effects. Out of all these universes, only the ones with accidentally lightweight Higgs bosons will allow atoms to form and thus give rise to living beings. But this “anthropic” argument is widely disliked for being seemingly untestable.

I am curious as to why, 'in this scenario, there are many universes'. What is it about this theory that necessitates that? And what would we be forced to conclude if there were not 'many universes'?

 

[kodama]

the idea is that other universes have different higgs masses - we happen to live in one where it is 126 gev, which is stable.

 

[Quotidian]

What 'other universes'? Put it like this - imagine if for some reason it was declared that there could not be 'other universes' - then what would we be obliged to admit must be the case?

 

[kodama]

What 'other universes'? Put it like this - imagine if for some reason it was declared that there could not be 'other universes' - then what would we be obliged to admit must be the case?

the Higgs boson mass and stability remains unexplained with current theories. Apparently SUSY isn't doing that, given its non-appearance

 

[Quotidian]

But how does the idea of other universes explain those things? There obviously can't be a causal relationship.

 

[ChrisVer]

But how does the idea of other universes explain those things? There obviously can't be a causal relationship.

this becomes a loop: because if there are other universes, the Higgs mass is a float, and so we happen to be in such a universe with the mass we observed [and which is unnatural]... in one universe it is 10^18GeV in some other it's 10^16 GeV, in this one it's 125GeV.

 

[haushofer]

But how does the idea of other universes explain those things? There obviously can't be a causal relationship.

It doesn't really imo; it says we cannot expect a natural explanation.

 

[cube137]

Is Superposition valid for the Constants of Nature? Can we say they have all values and "collapse" to a particular value?

 

[ChrisVer]

Is Superposition valid for the Constants of Nature? Can we say they have all values and "collapse" to a particular value?

I am not an expert, but I wouldn't call it a collapse... rather they are turned [if you "accept" the multiverse explanation]

 

[cube137]

this becomes a loop: because if there are other universes, the Higgs mass is a float, and so we happen to be in such a universe with the mass we observed [and which is unnatural]... in one universe it is 10^18GeV in some other it's 10^16 GeV, in this one it's 125GeV.

If the value of the higgs being 125 Gev was an accident of this universe, how could it be stable for 13.8 billion years? The value was produced from random "quantum fluctuation" during the big bang? But fluctuation couldn't have lasted for 13.8 billion years... just a few nanoseconds like virtual particles...

 

[ChrisVer]

i found a typo in p#9: turned was supposed to be tuned.

f the value of the higgs being 125 Gev was an accident of this universe, how could it be stable for 13.8 billion years?

Why would it change? (if there is nothing crazy going on with the vacuum expectation value)..

I mean you can hold a gun and start moving it up and down, once you pull the trigger, the bullet is going to hit a specified spot... if the constants were determined by quantum fluctuations, then once the latter "stopped" the values of the constants were frozen.