World made up of 2nd & 3rd Generation particles

[Vanadium 50]

I just want to know what is the purpose of the 2nd and 3rd generation particles

What is the purpose of a giraffe? Or Pluto? Or earthquakes?

 

[nikkkom]

Thanks. I was thinking how to create a separate thread about higgless world without being banned. Good to know it already existed. Now for the goal of this thread. I just want to know what is the purpose of the 2nd and 3rd generation particles. I thought they could create stable worlds but many here gave good arguments why they can't. But why 3 generations. What would happen if there were no 2nd and 3rd generation particles. Would molecules and atoms still be stable or coherent or couldn't they exist at all?

Molecules and atoms would be almost the same.

The generations may have something to do with baryogenesis. Although we don't yet have a good model how that could have worked, CP symmetry violations can be responsible for it. IIRC with just one generation, SM has no CP-violating terms.

The number of flavors affects beta functions running. More flavors weaken QCD confinement. In one-generation Universe, confinement would be a bit stronger.

More importantly, in one-generation Universe, (unbroken) weak isospin force could exhibit confinement too! Not sure this would significantly affect a broken phase.

 

[nikkkom]

However, my hunch is that existence of three generation still awaits its explanation.

For me, most curious are the unexplained mass relationships between generations: Koide formula for leptons, its weaker quark cousins, top quark to Higgs Yukawa coupling being equal to exactly 1.00 within experimental measurement errors. There should be a reason for these.

 

[cube137]

However, my hunch is that existence of three generation still awaits its explanation.

For me, most curious are the unexplained mass relationships between generations: Koide formula for leptons, its weaker quark cousins, top quark to Higgs Yukawa coupling being equal to exactly 1.00 within experimental measurement errors. There should be a reason for these.

With only the Higgs discovered and possibly nothing more for the entire LHC run and even newer colliders in the future and for the duration of all physicists lifetimes. I guess the best thing theoretical physicists do (lacking any experimental guidance) is just guess. Please cite any papers that attempt to explain the reasons for the 3 generations. Also top quark is heavier than higgs.. what do you mean exactly 1.00. I know meaning of Yukawa coupling, please elaborate.

 

[nikkkom]

With only the Higgs discovered and possibly nothing more for the entire LHC run and even newer colliders in the future and for the duration of all physicists lifetimes. I guess the best thing theoretical physicists do (lacking any experimental guidance) is just guess.

Not at all. There is still much to do for experimentalists: measuring masses of particles, especially higgs, top, bottom, tau with higher precision. Measure neutrino masses. Measure CKM and PNMS matrix elements. Measure production and decay cross-sections and branching ratios. Muon magnetic moment. Proton spin distribution. And so on...

Also top quark is heavier than higgs.. what do you mean exactly 1.00. I know meaning of Yukawa coupling, please elaborate.

Yukava couplings of fermions are $y_f = \sqrt{2}m_f/v$, where v is Higgs VEV. For top, y_t = 0.996 +- 0.006

 

[cube137]

Not at all. There is still much to do for experimentalists: measuring masses of particles, especially higgs, top, bottom, tau with higher precision. Measure neutrino masses. Measure CKM and PNMS matrix elements. Measure production and decay cross-sections and branching ratios. Muon magnetic moment. Proton spin distribution. And so on...

Yukava couplings of fermions are $y_f = \sqrt{2}m_f/v$, where v is Higgs VEV. For top, y_t = 0.996 +- 0.006

But the above are just "more precise measurement". I remembered the words of Lord Kevin in the 1800s "There is nothing new to be discovered in physics now, All that remains is more and more precise measurement.".

The hottest thing now and in fact the LHC revolves around the Hierarchy Problem. This is also my main interests. Without Supersymmetry and Multiverse.. how are you supposed to solve for the Hierarchy Problem of the Higgs or why it doesn't reach Planck mass. This is why I'm interested in the 3 generations and others... to get clue to solve the Hierarchy Problem. If you have some ideas. Please post some in the BSM forum.

 

[nikkkom]

But the above are just "more precise measurement".

More precise measurements can give hints for new theories. If after more precise measurement top's Yukava will be not ~0.996(6), but say ~0.99999993(11), then it's clearly a hint that it's really exactly 1, and more theorists will start seriously looking for explanations why.

More precise measurements can find definite discrepancies with SM, which also would give theorists some work to do.

 

[mfb]

But the above are just "more precise measurement". I remembered the words of Lord Kevin in the 1800s "There is nothing new to be discovered in physics now, All that remains is more and more precise measurement.".

And later, exactly those more precise measurements lead to quantum mechanics, which revolutionized physics (and chemistry). Discoveries don't have to happen at higher energies, they can also occur at increased precision.

If you have some ideas. Please post some in the BSM forum.

The right place for new ideas are publications. We can then discuss the publications here (sometimes preprints are acceptable). Skipping the publication part doesn't work.

More precise measurements can give hints for new theories. If after more precise measurement top's Yukava will be not ~0.996(6), but say ~0.99999993(11), then it's clearly a hint that it's really exactly 1, and more theorists will start seriously looking for explanations why.

Well, we won't get more than about an order of magnitude precision with the LHC. The ILC could make even more precise measurements (~15 MeV, 10^-4 precision).

 

[arivero]

The right place for new ideas are publications

We could rephrase: "if you know of publications of new ideas, please post in the BSM forum".

 

[cube137]

And later, exactly those more precise measurements lead to quantum mechanics, which revolutionized physics (and chemistry). Discoveries don't have to happen at higher energies, they can also occur at increased precision.The right place for new ideas are publications. We can then discuss the publications here (sometimes preprints are acceptable). Skipping the publication part doesn't work.Well, we won't get more than about an order of magnitude precision with the LHC. The ILC could make even more precise measurements (~15 MeV, 10^-4 precision).

What ILC? Will they even continue with it? according to Wiki the initial motivations for it are:

"At the ILC physicists hope to be able to:

• Measure the mass, spin, and interaction strengths of the Higgs boson
• If existing, measure the number, size, and shape of any TeV-scale extra dimensions
• Investigate the lightest supersymmetric particles, possible candidates for dark matter "

With null results of the supersymmetric particles and no extra dimensions.. we only have the higgs and this doesn't fully tally with their initial motivation, would Japan even spend $10 billion dollars just to see the Higgs mass in more significant digits and other decay modes?

Also in the linear collider own website https://www.linearcollider.org/ILC/Why-do-we-need-the-ILC/The-science it is said:

"For now, though, our view is obscure by a lack of knowledge of Terascale physics. Data from ILC would bring the Terascale into focus and give us a telescope to the beyond. The ILC would provide a view of energies trillion times beyond its own – into the ultrahigh-energy realm where nature's force might become unified."

Without the supersymmetric particles and extra dimensions.. what would they peek at the Terascale? And the last sentences may be wrong.. it's saying the ILC can collide at GUT energies when it can't even reach 1 TeV. Wiki said:
"The International Linear Collider (ILC) is a proposed linear particle accelerator.[1] It is planned to have a collision energy of 500 GeV initially, with the possibility for a later upgrade to 1000 GeV (1 TeV)."

However, my hunch is that existence of three generation still awaits its explanation.

For me, most curious are the unexplained mass relationships between generations: Koide formula for leptons, its weaker quark cousins, top quark to Higgs Yukawa coupling being equal to exactly 1.00 within experimental measurement errors. There should be a reason for these.

Do you have a complete listing of coincidences as regards the 3 generations in terms of mass or other parameters?
Do you know of any savant physicist? Math Savants can see patterns that others can't (like why there are 3 generations or why SU(3)xSU(2)XU(1)). Remember they can solve for the square root of 20 plus digit numbers in split seconds without calculator. So in these desperate times where the nightmare scenario has come true, we need to avail the services of math savants!

 

[nikkkom]

Do you have a complete listing of coincidences as regards the 3 generations in terms of mass or other parameters?

arivero's observations on Koide-like mass relations for quarks:
http://viavca.in2p3.fr/presentations/koide_formula_beyond_charged_leptons.pdf

Top quark and Higgs boson mass, their running and vacuum stability:
https://arxiv.org/pdf/1512.01222v1.pdf

Coincidences... How about these?

$\sum m_f^2 + \sum m_b^2 = v^2$
A stronger version of the above, the two parts of the sum may in fact be equal:
$\sum m_f^2 = \sum m_b^2 = v^2/2$
If the above is true, then sum of all fermions' Yukavas' squares are 1: $\sum y_f^2 = 1$
(this should be better for vacuum stability than $y_t=1$).

$m_W^2 + m_Z^2 = m_H^2$
$2 m_W + m_Z = 2 m_H$

The above coincidences hold within, or close to 3-sigma bounds of current experimental error bars. Getting better experimental data on masses is interesting for strengthening or disproving them.

Coincidences are interesting, but without theories explaining them they are "only numerology". How about these?
Vacuum energy is zero, therefore corrections from fermions and bosons should cancel (doesn't it mean that $\sum m_f^2 = \sum m_b^2$?).
Higgs λ should run to exactly 0 in UV limit ("vacuum is stable").

Take these with a large grain of salt. I'm no physicist.

Do you know of any savant physicist? Math Savants can see patterns that others can't (like why there are 3 generations or why SU(3)xSU(2)XU(1)). So in these desperate times where the nightmare scenario has come true, we need to avail the services of math savants!

My understanding is that "nightmare scenario" phrase refers only to the fact that SUSY/superstring/supergravity people's hopes were dashed when LHC found no superpartner particles. I understand those guys - they spend some 30 years working on those theories, and SUSY does have very nice properties (for example, a recent paper where *five-loop* N=4 SYM was proven to be not merely renormalizable, but *finite*!). Supersymmetry would solve a lot of problems. It is a "nightmare" when you work on it for so long, and it gives you such promising results... and then it's not seen in experiments.

Re "savant physicists". I think most professional physicists are not exactly what you'd classify as "normal people" :)
How on Earth did Dirac see that relativistic electron wavefunction needs to be a four-component vector, not two-component?
Don't worry, they will crack it sooner or later.

 

[ohwilleke]

nikkkom has hit many of my favorites. But there are a few more of interest that bear mention:

The Gell-Mann-Okubo mass formula
https://en.wikipedia.org/wiki/Gell-Mann–Okubo_mass_formula

While the Higgs boson mass is significantly greater than the 123.11 GeV that is one half of the Higgs vev, one can get to a very close approximation of the true Higgs boson mass if you assume that 1/2 of the Higgs vev is the tree level approximation, and that higher loop corrections adjust its mass in approximately the same direction and magnitude as the tree-level mass of the W gauge boson MW = ½gv = 78.9 GeV does to its observed mass of 80.4 GeV. See http://arxiv.org/abs/1502.06438

Most of arivero's observations on Koide-like mass relations for quarks involves triples of two down-type and one-up type quarks, or two up-type and one-down type quarks. But, the error in the mass of the "odd man out" in the triples is pretty much across the board approximately equal to the mass of omitted down-type quark (in the two downs, one up triples), or the mass of the omitted up-type quark (in the two ups, one down triples) times the CKM matrix element for the "odd man out" in the triple to the omitted quark. This is suggestive of the notion that flavor changing W boson interactions may dynamically give rise to the relative masses of quarks and charged leptons.

Another nifty one was described in a poster presentation at the Neutrino 2016 Conference:

Poster session 3 – Wednesday 6 July

P3.037 Gravitationally confined relativistic neutrinos

C Vayenas1,2, A Fokas3,4 and D Grigoriou1

1University of Patras, Greece, 2Division of Natural Sciences, Greece, 3University of Cambridge, UK, 4University of Southern California, USA

Combining special relativity, the equivalence principle and Newton’s universal gravitational law with gravitational rather than rest masses, one computes that gravitational interactions between relativistic neutrinos with kinetic energies above 10 MeV are very strong and can lead to formation of gravitationally confined composite structures. One may model the formation of such composite structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution leads to composite state radii close to 1 fm and neutrino velocities so close to c, that the corresponding Lorentz factor, gamma, values are of the order of 5*109. It is thus found that when the neutrino rest masses are of the order of 0.05 eV/c2, then the mass, 3(gamma)mo, of such three rotating neutrinos structures is very similar to that of hadrons (~ 1 GeV/c2). The thermodynamics of the phase condensation of neutrinos to form such structures are compared with QCD calculations for the quark-gluon condensation temperature.

Using the same approach we find that the mass of relativistic rotating Ve – e+/- pairs is 81 GeV/c2, close to that of W+/-bosons.

It is possible to come up with a single constant parameterization of the CKM model (the single parameter is the Cabbio angle) that is very close to experimentally measured values (basically an elaboration of the Wolfenstein parameterization) even though it takes four parameters to do so for any reasonably general set of CKM matrix entries that aren't linked by a deeper theory. But, this is partially because the accuracy of the measurements some of the elements isn't all that precise.

Do first generation fermion masses arise from the self-interactions of those particles? http://www1.jinr.ru/Pepan/2011_v42/v-42-5/04_boya.pdf

Frank Wilczek teased in an interview conducted early this year that he is on the verge of proving for the first time in a mathematically rigorous manner that renormalization really is a valid mathematical technique with broad implications:

What I’ve been thinking about today specifically is something of a potential breakthrough in understanding our fundamental theories of physics. We have something called a standard model, but its foundations are kind of scandalous. We have not known how to define an important part of it mathematically rigorously, but I think I have figured out how to do that, and it’s very pretty. I’m in the middle of calculations to check it out...

It’s a funny situation where the theory of electroweak or weak interactions has been successful when you calculate up to a certain approximation, but if you try to push it too far, it falls apart. Some people have thought that would require fundamental changes in the theory, and have tried to modify the theory so as to remove the apparent difficulty. What I’ve shown is that the difficulty is only a surface difficulty. If you do the mathematics properly, organize it in a clever way, the problem goes away. It falsifies speculative theories that have been trying to cure a problem that doesn’t exist. It’s things like certain kinds of brane-world models, in which people set up parallel universes where that parallel universe's reason for being was to cancel off difficulties in our universe—we don’t need it. It's those kinds of speculations about how the foundations might be rotten, so you have to do something very radical. It’s still of course legitimate to consider radical improvements, but not to cure this particular problem. You want to do something that directs attention in other places.

Better measurements of fundamental constants may make it possible to test "quark-lepton complementarity" which is the idea that the CKM matrix and PMNS matrix when expressed in comparable parameterizations can be used to predict each other from some sort of simple relationship. https://arxiv.org/abs/1203.1563

There is also a huge amount of physics to be done simply better understanding the Standard Model, and in particular, the implications of QCD calculated from first principles. For example, we still only a dimly understand why we observe the scalar and axial vector mesons with the masses that we observe, we don't observe glueballs at the masses where they are predicted to be, and we still can't calculate parton distribution functions of hadrons from first principles, even though, in principle if the SM is correct, all of these things should be possible to deduce purely from the SM Lagrangian and the values of already reasonably accurately measured fundamental constants. Many of the mathematical barriers involved to doing calculations in QCD are also shared with those involved in doing quantum gravity calculations, because self-interacting carrier bosons makes the path integrals involved converge much more slowly than they would otherwise. A lot of new physics could be hinted at if the strong force coupling constant behaves differently at high energies than predicted by renormalization in the SM.

 

[cube137]

arivero's observations on Koide-like mass relations for quarks:
http://viavca.in2p3.fr/presentations/koide_formula_beyond_charged_leptons.pdf

Top quark and Higgs boson mass, their running and vacuum stability:
https://arxiv.org/pdf/1512.01222v1.pdf

Coincidences... How about these?

$\sum m_f^2 + \sum m_b^2 = v^2$
A stronger version of the above, the two parts of the sum may in fact be equal:
$\sum m_f^2 = \sum m_b^2 = v^2/2$
If the above is true, then sum of all fermions' Yukavas' squares are 1: $\sum y_f^2 = 1$
(this should be better for vacuum stability than $y_t=1$).

$m_W^2 + m_Z^2 = m_H^2$
$2 m_W + m_Z = 2 m_H$

The above coincidences hold within, or close to 3-sigma bounds of current experimental error bars. Getting better experimental data on masses is interesting for strengthening or disproving them.

Coincidences are interesting, but without theories explaining them they are "only numerology". How about these?
Vacuum energy is zero, therefore corrections from fermions and bosons should cancel (doesn't it mean that $\sum m_f^2 = \sum m_b^2$?).
Higgs λ should run to exactly 0 in UV limit ("vacuum is stable").

Take these with a large grain of salt. I'm no physicist.
My understanding is that "nightmare scenario" phrase refers only to the fact that SUSY/superstring/supergravity people's hopes were dashed when LHC found no superpartner particles. I understand those guys - they spend some 30 years working on those theories, and SUSY does have very nice properties (for example, a recent paper where *five-loop* N=4 SYM was proven to be not merely renormalizable, but *finite*!). Supersymmetry would solve a lot of problems. It is a "nightmare" when you work on it for so long, and it gives you such promising results... and then it's not seen in experiments.

Re "savant physicists". I think most professional physicists are not exactly what you'd classify as "normal people" :)
How on Earth did Dirac see that relativistic electron wavefunction needs to be a four-component vector, not two-component?
Don't worry, they will crack it sooner or later.

(I'll ponder on your computations above and slowly digest it).
At this point I just want to get your attention that I think you are misunderstanding something or underestimating something huge. The Nightmare scenario is not only for SUSY/superstring/supergravity people but for all of us. Why. First. Do you understand the meaning of the Hiearchy Problem of the Higgs or why its mass is so low in spite of quantum contributions from other particle including the Planck mass? Supersymmetry is best solution for it. If you are not into SUSY. How do you solve the Hiearchy Problem then? See intro material

http://stat-athens.aueb.gr/~jpan/Science_Higgs.pdf

"Many particle physicists say their greatest fear is that their grand new
machine—the Large Hadron Collider (LHC) under construction at the
European particle physics laboratory, CERN, near Geneva, Switzerland—
will spot the Higgs boson and nothing else. If so, particle physics
could grind to halt, they say. In fact, if the LHC doesn’t reveal a plethora
of new particles in addition to the Higgs, many say they would rather it
see nothing new at all."

The article above also mentioned about the ILC and why it could be more difficult for its approval if only the higgs was found.

Ladies and gentlemen.. we are in very dire situation now.. the Hierarchy Problem is a problem at the heart of physics.

 

[ohwilleke]

Ladies and gentlemen.. we are in very dire situation now.. the Hierarchy Problem is a problem at the heart of physics.

I totally disagree. The Hierarchy Problem is an artificial construct of physicists trying to second guess Nature's determination of the physical constants of the universe. And, if the physical constants of the universe look "unnatural" this simply means that the physicists are looking at the issue from the wrong perspective.

For example, if you see the origin of the Higgs mass in terms of conjectured formulas like ∑m^2f+∑m^2b=v^2 or ∑m^2f=∑m^2b=v2/2 (which may be sufficient to accomplish the cancelations that SUSY does far more crudely) then the Higgs boson mass doesn't look unnatural in the least. Similarly, if you look at the origin of the Higgs mass in terms of using renormalization to back out of a zero value at the Planck scale with an appropriate value for quantum gravity, again, there is no hierarchy problem.

Naturalness, the hierarchy problem and the strong CP problem are all faux problems of presumptuous physicists, instead of real problems with our understanding of physics. Trying to solve these non-problems just sends you down a rabbit hole and distracts you from what should really matter which is finding laws of physics that explain the empirically measured reality, rather than second guessing the laws of Nature that observation demonstrates.

Similarly, a lot of pretty bad physics is motivated by a desire to make baryon number and lepton number zero at the time of the Big Bang, but Nature is not obligated to oblige us with a universe that has those initial conditions, and all efforts to measure B and L number violating processes to truly stunning precision have come up empty handed again and again and again in multiple different contexts.

 

[cube137]

I totally disagree. The Hierarchy Problem is an artificial construct of physicists trying to second guess Nature's determination of the physical constants of the universe. And, if the physical constants of the universe look "unnatural" this simply means that the physicists are looking at the issue from the wrong perspective.

For example, if you see the origin of the Higgs mass in terms of conjectured formulas like ∑m^2f+∑m^2b=v^2 or ∑m^2f=∑m^2b=v2/2 (which may be sufficient to accomplish the cancelations that SUSY does far more crudely) then the Higgs boson mass doesn't look unnatural in the least. Similarly, if you look at the origin of the Higgs mass in terms of using renormalization to back out of a zero value at the Planck scale with an appropriate value for quantum gravity, again, there is no hierarchy problem.

Naturalness, the hierarchy problem and the strong CP problem are all faux problems of presumptuous physicists, instead of real problems with our understanding of physics. Trying to solve these non-problems just sends you down a rabbit hole and distracts you from what should really matter which is finding laws of physics that explain the empirically measured reality, rather than second guessing the laws of Nature that observation demonstrates.

Similarly, a lot of pretty bad physics is motivated by a desire to make baryon number and lepton number zero at the time of the Big Bang, but Nature is not obligated to oblige us with a universe that has those initial conditions, and all efforts to measure B and L number violating processes to truly stunning precision have come up empty handed again and again and again in multiple different contexts.

Can you write a paper at arxiv to placate us who are sympathizer with the nightmare scenario. Actually the first book I read about it is Lisa Randall Warped Passages. If there is some kind of extra dimensions.. she said "In fact, when energies reach about a TeV, the effects of five-dimensional gravity would be enormous..". So since extra dimensions and supersymmetry are not seen. Even Lisa Randall was worried. And if you use renormalization to back out of a zero value at the Planck scale.. what quantum gravity theory are you proposing that would solve the Hierarchy Problem? What is exactly your solution to the Hiearchy Problem? Please elaborate. Do you know Scale Symmetry? I posted a message at BSM about Scale symmetry but no one replied to it because people don't know what it is. I think scale symmetry is also called conformal symmetry. If you know a bit about it. Please share at thought or two at https://www.physicsforums.com/threads/what-you-think-of-scale-symmetry.883237/ And oh even Nobel Laurette David Gross is worried (while you arent'.. so please elaborate your solution to the Hierarchy Problem). I read in http://arxiv.org/pdf/1406.1441v1.pdf

"In his overview talk[1] at Strings 2013, David Gross discussed the “nightmare sce-
nario” in which the Standard Model Higgs boson is discovered at the LHC but no
other new short-distance physics, in particular no signal for SUSY, is seen. He called
it the “extreme pessimistic scenario” but also said it was looking more and more likely
and (if it is established) then, he acknowledged

“We got it wrong.” “How did we misread the signals?” “What to do?”.

He said that if it comes about definitively the field, and string theorists in particular,
will suffer badly. He said that it will be essential for theorists who entered the
field most recently to figure out where previous generations went wrong and also to
determine what experimenters should now look for."

 

[ohwilleke]

The point is that the hierarchy problem is not a "problem" in the ordinary sense of the word and therefore doesn't call for an answer.

The physical constants of Nature have various values that are a fact of life. And, as long at those particular values that really exist in Nature are internally consistent with each other (for example, leading to the sum of all possible results of each possible situation adding up to 100% in each case and not leading to contradictory answers, in which case we probably screwed up measuring something), physical constants just "are", and it is basically a category error to ask "why" they are that value and not another when they are axioms and not theorized conclusions that flow from some other axioms.

There is nothing that forbids Nature from having a dozen huge contributions to another value that almost, but not quite cancel out. Nature is under no obligation to have terms of order 1 or any other order it wishes. And, it is illogical and absurd to use a definition of "naturalness" that results in Nature being unnatural. When that happens, it means the chain of reasoning screwed up somewhere.

The "hierarchy problem" is solved because all of the contributions to the total add up just so. The inputs are not moveable. They stay the same for all of eternity, in all times and places. And, as long as they add up correctly, it is all cool. The fact that some physicists think that this is ugly is a sign of their lack of sophistication and good taste, and not a "problem" with Nature that needs to be solved.

Now, it could be (and probably is the case) that at least some of the experimentally measured constants of the Standard Model could be derived theoretically from some of the other experimentally measured constants of the Standard Model, if we only knew the functional relationship between them.

For example, I would bet all of the equity in my house that the mass of the tau lepton predicted by Koide's rule and the measured values of the muon mass and electron mass are a more accurate estimate the true mass of the tau lepton than the mass of the tau lepton that is measured experimentally. And, if Koide's rule is correct, then the Standard Model has one less experimentally measured parameter.

But, relationships like those are opportunities to discover new "within the Standard Model" physics, and not invitations to say that Nature screwed it up. Nature is always right and our challenge is to come up with simplified reasons consistent with the data why Nature is right, not to sit around trying to come up with reasons why Nature is wrong, which is essentially what you are doing when you call the "hierarchy problem" a problem in the first place.

I'm not saying that physicists having Nightmares are less qualified physicists than I am. I'm saying that their natural philosophy is leading them astray, and they would be well advised to worry about something different instead.

 

[cube137]

The point is that the hierarchy problem is not a "problem" in the ordinary sense of the word and therefore doesn't call for an answer.

The physical constants of Nature have various values that are a fact of life. And, as long at those particular values that really exist in Nature are internally consistent with each other (for example, leading to the sum of all possible results of each possible situation adding up to 100% in each case and not leading to contradictory answers, in which case we probably screwed up measuring something), physical constants just "are", and it is basically a category error to ask "why" they are that value and not another when they are axioms and not theorized conclusions that flow from some other axioms.

There is nothing that forbids Nature from having a dozen huge contributions to another value that almost, but not quite cancel out. Nature is under no obligation to have terms of order 1 or any other order it wishes. And, it is illogical and absurd to use a definition of "naturalness" that results in Nature being unnatural. When that happens, it means the chain of reasoning screwed up somewhere.

The "hierarchy problem" is solved because all of the contributions to the total add up just so. The inputs are not moveable. They stay the same for all of eternity, in all times and places. And, as long as they add up correctly, it is all cool. The fact that some physicists think that this is ugly is a sign of their lack of sophistication and good taste, and not a "problem" with Nature that needs to be solved.

Now, it could be (and probably is the case) that at least some of the experimentally measured constants of the Standard Model could be derived theoretically from some of the other experimentally measured constants of the Standard Model, if we only knew the functional relationship between them.

For example, I would bet all of the equity in my house that the mass of the tau lepton predicted by Koide's rule and the measured values of the muon mass and electron mass are a more accurate estimate the true mass of the tau lepton than the mass of the tau lepton that is measured experimentally. And, if Koide's rule is correct, then the Standard Model has one less experimentally measured parameter.

But, relationships like those are opportunities to discover new "within the Standard Model" physics, and not invitations to say that Nature screwed it up. Nature is always right and our challenge is to come up with simplified reasons consistent with the data why Nature is right, not to sit around trying to come up with reasons why Nature is wrong, which is essentially what you are doing when you call the "hierarchy problem" a problem in the first place.

I'm not saying that physicists having Nightmares are less qualified physicists than I am. I'm saying that their natural philosophy is leading them astray, and they would be well advised to worry about something different instead.

Let's say Supersymmetry, Extra Dimensions and Scale Symmetry were categorically ruled out already. And we are left with Multiverse. Do you believe in Multiverse in which all combinations of the constant produced countless parallel universe? Or do you believe in alternative to Multiverse or Intelligent Design where our universe parameters were built or designed by something? Multiverse or Intelligent Design, which do you pick, and why?

 

[mfb]

ATLAS and CMS analyzed 0.5% of the expected ultimate LHC dataset at 13-14 TeV. At the same luminosity fraction, the Tevatron experiments were still busy searching for the top! Sure, it would be nice to have something very early, but in terms of discovery potential the LHC just started. It is way too early to claim that it won't find anything.

ILC funding would be easier with new particles below 0.5 TeV, but there is also a strong motivation from precision Higgs and top physics.

And the last sentences may be wrong.. it's saying the ILC can collide at GUT energies when it can't even reach 1 TeV.

Do you really think that it might be wrong? Are you an ILC expert now?
Precision experiments allow to probe much higher energy scales indirectly. New physics beyond the direct reach should still appear in production cross sections, branching ratios and so on.

Let's say Supersymmetry, Extra Dimensions and Scale Symmetry were categorically ruled out already. And we are left with Multiverse.

False dichotomy.
"Let's say we ruled out that this object is an apple. We are left with 'it is a banana'."
"Multiverse" is not even a theory.

Somehow this thread is getting off-topic.

 

[cube137]

ATLAS and CMS analyzed 0.5% of the expected ultimate LHC dataset at 13-14 TeV. At the same luminosity fraction, the Tevatron experiments were still busy searching for the top! Sure, it would be nice to have something very early, but in terms of discovery potential the LHC just started. It is way too early to claim that it won't find anything.

Just one thing to clear up something. I posted the following in BSM but no replies. Can you please answer it here. I asked: They say (esp. Lubos) we only have 1% of the LHC data.. does it mean if we see the other 99% of data, there is a possibility the 750 GeV Diphoton bump can still appear? Is the data similar to say resolution of a picture.. where the 1% means it is resolution of 120x80 and scouting the entire 99% means the resolution is really 12000x8000 but you can make out the gross picture already at 120x80? or is scouting 99% of rest of LHC data specifically related to higher TeV meaning those already excluded are forever excluded?

 

[mfb]

It is more of the same (well, the energy might increase from 13 to 14 TeV, but that is not a large step), with more data you can see smaller signals.

Higher-energetic particles tend to produce smaller signals, so more data means you (a) can search up to higher masses and (b) can search the low-energetic range for smaller coupling strengths.

 

[cube137]

It is more of the same (well, the energy might increase from 13 to 14 TeV, but that is not a large step), with more data you can see smaller signals.

Higher-energetic particles tend to produce smaller signals, so more data means you (a) can search up to higher masses and (b) can search the low-energetic range for smaller coupling strengths.

To be on topic. It means there is no more possibility of seeing 4th generation particles below 1 TeV when luminosity goes from 0.5% to 100%? and no possibility of the Diphoton bump appearing again because of b which is searching only for smaller coupling strengths in the low-energetic range? But what is an example of smaller coupling strengths of say the 2nd and 3rd gen particles (to be on topic)?

 

[mfb]

To be on topic. It means there is no more possibility of seeing 4th generation particles below 1 TeV when luminosity goes from 0.5% to 100%?

It is possible if their mixing with the other three generations is very weak. What do you mean by "example"? Mixing and coupling strengths are just physical parameters. An example is "0.001", does that help?

and no possibility of the Diphoton bump appearing again because of b which is searching only for smaller coupling strengths in the low-energetic range?

Everything can appear again - ATLAS and CMS set exclusion limits based on what they did (not) see this year, but those exclusion limits are never zero. There could be a particle, if its cross section is much smaller than what the 2015 data suggested. But that means the 2015 data was a statistical fluctuation even if there is a particle.

 

[cube137]

It is possible if their mixing with the other three generations is very weak. What do you mean by "example"? Mixing and coupling strengths are just physical parameters. An example is "0.001", does that help?
Everything can appear again - ATLAS and CMS set exclusion limits based on what they did (not) see this year, but those exclusion limits are never zero. There could be a particle, if its cross section is much smaller than what the 2015 data suggested. But that means the 2015 data was a statistical fluctuation even if there is a particle.

Do you have a reference what is meant by particle mixing? Is it like the top quark being made or right quark and left quark.. or the photon a mixing of weak Isospin vs Hypercharge. I'd like to understand the context of what you meant a 4th gen particle can have mixing with the other three generations.

 

[nikkkom]

At this point I just want to get your attention that I think you are misunderstanding something or underestimating something huge. The Nightmare scenario is not only for SUSY/superstring/supergravity people but for all of us. Why. First. Do you understand the meaning of the Hiearchy Problem of the Higgs or why its mass is so low in spite of quantum contributions from other particle including the Planck mass? Supersymmetry is best solution for it. If you are not into SUSY. How do you solve the Hiearchy Problem then?

I understand the problem.
I'd look for other ways (theories) to explain how different corrections to Higgs mass cancel out.

 

[mfb]

This thread got way too incoherent in its topic. Please make separate threads for separate topics, and stick to the topic within those threads.

Do you have a reference what is meant by particle mixing?

The 4x4 equivalent of the CKM matrix.