What if the Higgs is not found by LHC and Tev, nor anything else

[ensabah6]

Technicolor models offer ways to break EWB that do not involve higgs, but do predict new observations at LHC energies.

Based on precision WW scattering, unitarity would be violated without the Higgs mechanism.

So if the Higgs, or something that plays its role, is not found, unitarity is violated which may mean QM needs to be revised.

If the Higgs, or something like it, is not found at LHC/TEV what would be the most Nobel-prize winning route

1- reformulate QM,
2- QM is wrong, unitarity is not preserved
3- maybe there is no true Electro-weak unification
4- consider other sources of Higgs field like neutrino condensates? perhaps dark energy?
5 perhaps preons or all particles are composites?Maybe NOT finding the Higgs is a lot like not finding the luminerous aether.

 

[Kevin_Axion]

What if? I hope we don't find any of the mechanisms actually, the field of particle physics and theoretical physics will be of a different nature and there will be a massive stimulus in research making the field much more exciting.

 

[ensabah6]

What if? I hope we don't find any of the mechanisms actually, the field of particle physics and theoretical physics will be of a different nature and there will be a massive stimulus in research making the field much more exciting.

I know that the Higgs is needed to explain EWB and mass generation and preserve unitarity in WW scattering, but it is unsatisfactory due to hieararchy and quadratic radiative corrections, resulting in postulation of SUSY, and SUSY requires explanation for flavor change, SUSY breaking, etc. Technicolor is offered as one alternative

What about exploring the idea that (a) there is no true electroweak unification or (b) unitarity is violated and QM is only an approximation that becomes invalid

 

[humanino]

Electroweak unification has already occurred.

 

[Kevin_Axion]

I said I hope, but I will not posit that nothing will be discovered. The Higgs will be found, there is much indirect evidence for it and with SUSY it's an almost pure theory of nature.

 

[ensabah6]

Electroweak unification has already occurred.

so what are the properties of weak force above unification? Is it infinite range?

 

[ensabah6]

I said I hope, but I will not posit that nothing will be discovered. The Higgs will be found, there is much indirect evidence for it and with SUSY it's an almost pure theory of nature.

So you are confident that as a pure theory of nature LHC will see SUSY?

 

[Kevin_Axion]

Sorry, let me rephrase that, if the LHC finds SUSY the MSSM will be the best theory or "purest" theory we have. Besides the MSSM, Superstring Theory will become the key area of research, this would be the Third Superstring Revolution, I believe.

 

[ensabah6]

Sorry, let me rephrase that, if the LHC finds SUSY the MSSM will be the best theory or "purest" theory we have. Besides the MSSM, Superstring Theory will become the key area of research, this would be the Third Superstring Revolution, I believe.

and if the LHC does not find it?

I do agree that LHC may help experimentally determine some of MSSM's parameters which can be used to help determine moduli parameters

 

[Kevin_Axion]

Logically, one must believe that SUSY exists, so much research is dependent on it, when I go onto arXiv (hep-th) the papers being published are either Supersymmetric Yang-Mills Theories or Gauge/Gravity Duality (which arose from M-Theory) Theories. A lot of the ideas have a fundamental derivation from SUSY we almost need it to exist just like we needed Quantum Mechanics and General Relativity too. (correct me if my reasoning is incorrect).

 

[ensabah6]

Logically, one must believe that SUSY exists, so much research is dependent on it, when I go onto arXiv (hep-th) the papers being published are either Supersymmetric Yang-Mills Theories or Gauge/Gravity Duality (which arose from M-Theory) Theories. A lot of the ideas have a fundamental derivation from SUSY we almost need it to exist just like we needed Quantum Mechanics and General Relativity too. (correct me if my reasoning is incorrect).

would you still believe in SUSY "logically" if, say by the year 2020-30, LHC and all searches for SUSY come up null?

 

[Kevin_Axion]

If no other idea is developed as a substitution then most likely, yes.

 

[ensabah6]

If no other idea is developed as a substitution then most likely, yes.

fair enough. But in this scenario, a null result for low-energy SUSY at LHC is unlikely to be the explanation for higgs stabilization since low-energy SUSY predicts little Higgs, neutralinos, and charged gluinos in LHC level energies

 

[humanino]

so what are the properties of weak force above unification? Is it infinite range?

Did you notice the change of slope for CC in the plot ? That is the only meaning I can imagine for "infinite range" at such high scales. Of course the interaction occurs over short ranges, but the point if that we see unification of CC with NC (and NC contains the photon which is "infinite range"). If your question on "infinite range" has another meaning, please explain.

"logically" if, say by the year 2020-30, LHC and all searches for SUSY come up null?

It is not a matter of belief, the "null" is not a logical possibility. Either we see violation of unitarity as you said, and QM is falsified (most dramatic result, nobody expects that), or something unknown is proven to be there. If what is there to restore unitarity has been anticipated (single simple Higgs, SUSY, technicolor, extra-dim, combinations of previous, etc etc) we will most likely recognize it. Otherwise, there is little point into discussing what we have not anticipated, except that indeed it would be quite exciting. In all logical possibilities, something has been found. And it is not a surprise : the LHC has access to a region where the Higgsless SM is self-contradictory.

 

[strangerep]

[...]
The Higgs will be found, there is much indirect evidence for it

Could you please summarize the "indirect evidence"?

(I was still under the impression that the Higgs is in the SM only
because without it the QFT involving massive vector bosons
is nonrenormalizable.)

(?)

 

[ensabah6]

Did you notice the change of slope for CC in the plot ? That is the only meaning I can imagine for "infinite range" at such high scales. Of course the interaction occurs over short ranges, but the point if that we see unification of CC with NC (and NC contains the photon which is "infinite range"). If your question on "infinite range" has another meaning, please explain.It is not a matter of belief, the "null" is not a logical possibility. Either we see violation of unitarity as you said, and QM is falsified (most dramatic result, nobody expects that), or something unknown is proven to be there. If what is there to restore unitarity has been anticipated (single simple Higgs, SUSY, technicolor, extra-dim, combinations of previous, etc etc) we will most likely recognize it. Otherwise, there is little point into discussing what we have not anticipated, except that indeed it would be quite exciting. In all logical possibilities, something has been found. And it is not a surprise : the LHC has access to a region where the Higgsless SM is self-contradictory.

em is infinite range, photons massless,
w, z bosons weak is short range, massive bosons.

above ew unification is the weak force infinite range or short range.

is there any reason the mechanism for giving w z gauge bosons mass must be the same as what gives fermions mass?fermions and w bosons have electric charge. perhaps that is tied to inertial mass.

 

[humanino]

em is infinite range, photons massless,
w, z bosons weak is short range, massive bosons.

When your scale is above the weak boson mass (like $Q^2\sim10^4\text{GeV}^2$ in the plot), you can tell the difference neither between the infinite range of the photon and the massive weak bosons (since the interaction length or time is inversely proportional to the scale) , nor between the mass of those weak bosons and the massless case (because the masses all becomes negligible anyway). That is what the plot shows, in agreement with precise calculations (rather than hand-waving).

is there any reason the mechanism for giving w z gauge bosons mass must be the same as what gives fermions mass?

Yes there is. It's chiral symmetry. For instance, the same dynamical chiral symmetry breaking which gives large constituent quark masses to the u and d in the proton also generate the chiral quark condensate (which is a measure of the breaking) in the vacuum $<\bar{q}q>$. This mechanism alone generates masses for the weak bosons as well. Alas, this is too small to account for the entire mass of those weak bosons. Yet this is the observation leading to the concept of technicolor, which is a repetition of a more strongly coupled unbroken sector for which the Higgs would be a pseudo-Goldstone boson (analog to the QCD pion). The technirho would regulate WW scattering for instance.

This is all beautifully described in
Electroweak symmetry breaking: to Higgs or not to Higgs
by Christophe Grojean

 

[skippy1729]

Logically, one must believe that SUSY exists, so much research is dependent on it, when I go onto arXiv (hep-th) the papers being published are either Supersymmetric Yang-Mills Theories or Gauge/Gravity Duality (which arose from M-Theory) Theories. A lot of the ideas have a fundamental derivation from SUSY we almost need it to exist just like we needed Quantum Mechanics and General Relativity too. (correct me if my reasoning is incorrect).

Reasoning? It would be equally logical to say that Keynesian Economic Theory must be true since we have invested so much money in it; or, Christianity must be true since so many believe it.

Skippy

PS Please note that I am not offering any opinion of Supersymmetry, Keynsian economics or Christianity, only the logic involved.

 

[humanino]

One could as well interpret that many papers with SUSY are playgrounds/toy models which are easier to solve than the "real deal".

edit
Note that, this post neither is a judgement as to whether SUSY is realized. I am just saying that (independently of whether it is realized) SUSYs are often easier (while possibly messier).

 

[Kevin_Axion]

Belief in the context of Science is distinct, when one believes SUSY they support it until falsified. I'm saying one should believe in SUSY not due to the laborious work put into developing subject, rather because it expands our horizon of our knowledge. This doesn't just apply to SUSY but to all ideas developed by humanity, we learn and grow from the ideas we have, especially the ones that appear so natural like SUSY, the ones illuminate powerful ideas. It is these ideas that we keep until falsified. Falsification of Religion is a paradox in its own right people will continue to believe it and conclude it's true because unlike SUSY it can't be falsified. Now you see belief in Science is a product of curiosity and empirical/quantitative analysis while belief in religion is driven by faith separate from quantitative analysis, a belief that is unfalsifiable.

 

[diggy]

If nothing is found I don't see that nullifying the Standard Model much less QM. The SM would remain "philosophically" incomplete, and of course have loose ends, but its still the best description available.

 

[humanino]

If nothing is found I don't see that nullifying the Standard Model much less QM. The SM would remain "philosophically" incomplete, and of course have loose ends, but its still the best description available.

But what do you mean when you say "nothing is found" ? Do you mean "not even one Higgs" ? If we find a Higgs, we cannot say we "found nothing". So let me assume we do not find the Higgs (any Higgs). If you take the SM and remove the Higgs, then you predict violation of QM's unitarity in WW scattering. So either you find the violation (in which case, indeed the SM would win against our expectations), or the cross section for WW scattering remains well-behaved (it does not violate unitarity). There is no other logical possibility. In both cases again, one cannot conclude that the LHC "found nothing". If you find the unitarity violation, QM is falsified : that would be quite a finding ! If you do not find the unitarity violation, then something else must play the role of the Higgs. We know of such scenarios where unitarity is respected but nothing else seems to show up : those are hidden SUSY sectors. Wether those hidden SUSY sectors are real or not, there must be something regulating the WW scattering amplitude. IMHO that would ironically be the best case scenario to plead for ILC.

 

[diggy]

I meant not even find a Higgs or Susy within their measurement range.

My point was simply that modifying the fundamental ideas of QM is pretty far fetched. They have too broad of support from decades of measure. I guess you could say that would null the standard model, but I don't think it will null the other successes of the standard model. So I'd assume that would push the argument to more exotic, ala higher Susy additions/modifications of the SM. (Unless of course there was some sort of breakthrough elsewhere like string).

 

[humanino]

I meant not even find a Higgs or Susy within their measurement range.

Thank you for the precision.

My point was simply that modifying the fundamental ideas of QM is pretty far fetched. They have too broad of support from decades of measure.

I fully agree, and I do not think anybody anticipates that catastrophic fate. Note however that it is not really up to us : we will measure this WW scattering cross-section, and we will see wether it violates unitarity or not.

I guess you could say that would null the standard model, but I don't think it will null the other successes of the standard model.

Yes, I think it is important to keep that in mind. Nobody uses QED to design optical correcting lenses, so QED has not nullified the successes of classical wave theory. Neither did Einstein nullified Newton's mechanics. In those cases, I believe in some sense the effective theories become even better defined, since we understand their applicability.

So I'd assume that would push the argument to more exotic, ala higher Susy additions/modifications of the SM. (Unless of course there was some sort of breakthrough elsewhere like string).

Yes, if we do not find violation of unitarity, and we do not find anything to explain it (no Higgs, no technicolor, no extra-dim...) then we are left with (AFAIK) only hidden SUSY sectors. Many more SUSY sectors means that (when properly chosen) the signals will be too weak to distinguish from the background. Another way to say it : we would need to run the LHC for more than an order of decades to find them properly. In this situation, my opinion is that we logically have a case (maybe best case) for ILC. Evidently, that's quite arguable !

 

[diggy]

Luckily I don't think we have to lose sleep over this quite yet. It will be a while before LHC has enough luminosity to really start ruling out particles, especially ones that have undefined masses. I don't know if any of you followed the penta-quark search, but the mass was effectively "known" and it still took several experiments and years of old data to rule out its discovery (some tough word choices, hopefully that sentence was bearable).

 

[ensabah6]

When your scale is above the weak boson mass (like $Q^2\sim10^4\text{GeV}^2$ in the plot), you can tell the difference neither between the infinite range of the photon and the massive weak bosons (since the interaction length or time is inversely proportional to the scale) , nor between the mass of those weak bosons and the massless case (because the masses all becomes negligible anyway). That is what the plot shows, in agreement with precise calculations (rather than hand-waving).
Yes there is. It's chiral symmetry. For instance, the same dynamical chiral symmetry breaking which gives large constituent quark masses to the u and d in the proton also generate the chiral quark condensate (which is a measure of the breaking) in the vacuum $<\bar{q}q>$. This mechanism alone generates masses for the weak bosons as well. Alas, this is too small to account for the entire mass of those weak bosons. Yet this is the observation leading to the concept of technicolor, which is a repetition of a more strongly coupled unbroken sector for which the Higgs would be a pseudo-Goldstone boson (analog to the QCD pion). The technirho would regulate WW scattering for instance.

This is all beautifully described in
Electroweak symmetry breaking: to Higgs or not to Higgs
by Christophe Grojean

if e-w symmetry, SUSY symmetry, antimatter-matter symmetry can be broken, couldn't chiral symmetry be broken?

 

[Heraclitus]

What we forget here, about Higgs particle, is that the stake is our understanding of mass. SM requires a mechanism to produce masses to the different fields entering in it. It is interesting to note that this situation is rather similar to that of QCD, that is part of SM, at lower energies. The question is what gives mass to the gluon field. Is it possible that the mechanism at work is the same? Why should Nature have chosen different ways to obtain an identical result?

 

[tom.stoer]

What do you mean by "mass of the gluon field"? I guess you are talking about bound states, like glueballs.

To me the construction of the Higgs seems to be rather artificial (scalar particle; artificial potential which becomes increasingly complex in SUSY; quadratic diverence / mass scale problem, ...).

My expectation is that the Higgs is more or less an "effective field" which is to be explained via other fundamental degrees of freedom. Perhaps something like a W- and Z-self-energy, condensate or something like that. It is unclear to me if in such a scenario the Higgs could still be observed as a particle (a resonance, bound state or something like that) or if the Higgs would cease to exist at all.

 

[Heraclitus]

What do you mean by "mass of the gluon field"? I guess you are talking about bound states, like glueballs.

So far, we do not know if the states that diagonalize Yang-Mills quantum field theory at lower energies, with the coupling increasingly large, are the same of those used at higher energies and that we call gluons, with the coupling increasingly small. Massless gluons are good states when asymptotic freedom sets in. So, when we talk of glueballs, it is generally wrong to call them bound states of gluons.

To me the construction of the Higgs seems to be rather artificial (scalar particle; artificial potential which becomes increasingly complex in SUSY; quadratic diverence / mass scale problem, ...).

My expectation is that the Higgs is more or less an "effective field" which is to be explained via other fundamental degrees of freedom. Perhaps something like a W- and Z-self-energy, condensate or something like that. It is unclear to me if in such a scenario the Higgs could still be observed as a particle (a resonance, bound state or something like that) or if the Higgs would cease to exist at all.

I agree with your view that the current Higgs field entering into the SM appears rather artificial and, so far, no scalar particles have been ever seen. So, it is my view that, if new physics should come out, this is certainly in the Higgs sector.

 

[tom.stoer]

So far, we do not know if the states that diagonalize Yang-Mills quantum field theory at lower energies, with the coupling increasingly large, are the same of those used at higher energies and that we call gluons, with the coupling increasingly small. Massless gluons are good states when asymptotic freedom sets in. So, when we talk of glueballs, it is generally wrong to call them bound states of gluons.

It depends what you call gluons.

If you restrict this term to massless plane wave states of the gluon field, then I agree. But if you construct the QCD Hilbert space of physical states as the Fock space restricted by the Gauss law constraint in order to ensure gauge invariance, then you can construct color singulet "gluonic" operators on this space; you have a generic description of what "gluons" are, namely states in this physical subspace created ny gluonic operators. Of course the plane wave states are no longer part of this physical subspace as they violate the Gauss law.

So when I am talking about gluons I do not restrict them to plane waves (as seen in deep inelastic scattering = in the limit of asymptotoc freedom) but I mean the full, non-perturbative gluon field in QCD.

 

[Heraclitus]

It depends what you call gluons.

If you restrict this term to massless plane wave states of the gluon field, then I agree. But if you construct the QCD Hilbert space of physical states as the Fock space restricted by the Gauss law constraint in order to ensure gauge invariance, then you can construct color singulet "gluonic" operators on this space; you have a generic description of what "gluons" are, namely states in this physical subspace created ny gluonic operators. Of course the plane wave states are no longer part of this physical subspace as they violate the Gauss law.

So when I am talking about gluons I do not restrict them to plane waves (as seen in deep inelastic scattering = in the limit of asymptotoc freedom) but I mean the full, non-perturbative gluon field in QCD.

I agree with your non-perturbative definition. Now, I have to suppose that some dependence on the coupling is in these states. You should recover ordinary plane wave description when the coupling goes to zero. The states you get when the coupling goes to infinity are massive. This I mean by a gluon getting a mass. Classically you can see this in the following way. Let us consider the massless scalar field with equation

$$\partial^2\phi+\lambda\phi^3=0.$$

This has an exact solution

$$\phi(x)=\mu\left(\frac{2}{\lambda}\right)^\frac{1}{4}{\rm sn}(p\cdot x+\theta,i)$$

being sn a Jacobi elliptic function, $$\mu$$ and $$\theta$$ two integration constants. This holds provided the following dispersion relation holds

$$p^2=\mu^2\left(\frac{\lambda}{2}\right)^\frac{1}{2}$$

and so this massless field, due to the presence of a finite self-interaction, gives a massive solution. When you take the limit of the coupling going to zero you recover the ordinary perturbed massless field. Classically, you observe a similar situation for the Yang-Mills field provided the gauge coupling is taken to go to infinity.

 

[nickthrop101]

there is no evidence that the hiiggs boson actually exists, the master equation says so but supposably the higgs could just be a version of the tangled up calibi-yau spaces or effects of a different kind of gravity
saying thius i personly agree that the higgs exists, but i am just outlining other possibilitys.
we canjnot simply decide quantum mechanis is wrong unless we try and look at in a different way if we don't find it. :)

 

[Parlyne]

if e-w symmetry, SUSY symmetry, antimatter-matter symmetry can be broken, couldn't chiral symmetry be broken?

The problem with mass in the SM is that chiral symmetry is broken. The SU(2) interaction in the EW sector only "sees" left chiral fermion fields; but, Dirac mass terms necessarily involve both right and left chiral fields (in a chirally symmetric way). Thus, a Dirac mass cannot be SU(2) invariant. The solution in the SM is to spontaneously generate fermion masses using the same mechanism that spontaneously breaks the SU(2) symmetry.

 

[cph]

Technicolor models offer ways to break EWB that do not involve higgs, but do predict new observations at LHC energies.

Based on precision WW scattering, unitarity would be violated without the Higgs mechanism.

So if the Higgs, or something that plays its role, is not found, unitarity is violated which may mean QM needs to be revised.

If the Higgs, or something like it, is not found at LHC/TEV what would be the most Nobel-prize winning route

1- reformulate QM,
2- QM is wrong, unitarity is not preserved
3- maybe there is no true Electro-weak unification
4- consider other sources of Higgs field like neutrino condensates? perhaps dark energy?
5 perhaps preons or all particles are composites?


Maybe NOT finding the Higgs is a lot like not finding the luminerous aether.

GHOST FIELD

One could consider just a background ghost field (term) which is useful in the calculations, but has no physicality to it.