Severian

Such a precision is explained with a very small value of the expansion parameter (about 0.001). Currently the calculation is made to the forth order so the precision is very high. It is not correct to demand from new theories to overcome this precision - it would take too much effort from one person.

I stated this myself earlier in this thread. I agree that you would never calculate to this precision with a new theory. However, your new theory should not be in contradiction with this number, and you should do at least a basic calculation to ensure it isn't in contradiction.

It's simply that I couldn't help to notice that those were the exact images that were sent all around the web. They even featured in a National Geographic regarding the new facility being built there. A response, perhaps?

I am slightly curious how you think anyone working on ATLAS could produce their own pictures. There is a high magnetic field in the pit, so anything metal is not allowed inside, certainly not a camera. The only pictures in existence are the official ones which had to be taken in special conditions.

either you are fraudulent in nature, or you work at Cern. Do reply to the following.

You are right, I am a fraud, since I don't work at CERN. It was meant as a joke.

And, unlike you, I am not very interesting.

My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!

Here is a couple of mine:

And before the detector went in:

A few years ago I would certainly have labeled myself as a 'liberal'. But as I get older I am finding myself getting more conservative. Does that mean that I am a less 'critical' thinker than I was before? No, it is quite the opposite; I have become more critical.

To a certain extent this is because I have seen what 'change' can do. Being in higher education, I have seen the unbelievable drive in recent years of the 'liberals' to make education more 'inclusive'. This has undeniably led to a reduction in standards which make everyone suffer. We now have much more difficulty finding students capable of doing scientific research than we did before.

So conservatism is often rooted in a desire to preserve systems that work. Once something has been broken by tinkering liberals, it may never be the same again, and everyone will be worse off.

I now find myself as somewhere between liberal and conservative. I would like to see change in many areas, but that shouldn't be knee-jerk 'lets have a group hug' change. It should be well thought out, reasoned and motivated change, with honest tests and safety measures put in place to ensure the change is an improvement and a facility for changing it back if it is not.

Ironically enough, I am finding that some of the things I want to change most (so in some sense I am least 'conservative' about) and the things that the 'liberals' have introduced into our society in the guise of progress.

That's because everyone knows that the current theories are flawed -- they make a few wrong predictions, fail to make other predictions, and provide explanations that fundamentally disagree with each other (eg gravity caused by warped spacetime or gravitons)

Which theories are you taking about? The Standard Model, for example, has made no wrong predictions at all! In fact that is one of the big problems with particle physics at the moment - the Standard Model doesn't give us much leeway for going further. General relativity has also never made wrong predictions because we have been unable to test it on a quantum level. We don't have a consistent theory of quantum gravity (gravitons) yet.

While the new theory should be better, but that does not necessarily mean that it should be more accurate in its predictions. Copernicus' heliocentric theory did not produce more accurate results (some say it was less accurate), yet because of its elegance it was a good theory. (It was, of course, later modified to have elliptical orbits and more accurate results.)

Yes it does. It must have at least one prediction better than current theories. As Swanson has already pointed out Copernicus' theory explained something which was previously not explained (just modeled). If you could explain some part of current physics currently only modeled with a theory with very few parameters, we would be willing to listen. For example, if you had a hadronization model with one or two parameters, I could guarantee you an audience of 100s of enthusiastic experimentalists.

Your requirement that any new theories have better predictions is a ban on new theories on this site.

Only because the crackpots are too stupid to come up with anything semi-consistent.

I think that alternative (even crazy) theories should be allowed here, so that they can be developed or poked full of holes. Surely poking holes in a new theory is more interesting than answering the silly questions that take up half the threads and would be better answered by wikipedia or a quick google search? Surely people learn at least as much from this?

I do agree with this, but there has to be some level of standard. Look in the speculations forum and you will see that the majority of the suggestions can be discarded with just a moment's thought.

Severian--you seem to be more open minded than most as to the importance of new ideas and the measure which they must reach before even being considered as plausible.--

 

-For a start, was there something that inspired you to start this thread?

To be honest, it was rather the opposite point of view which led me to post this. At the time of posting we had been fooded by lots of people telling us that the Standard Model is wrong and that they have a revolutionary idea to replace it. This would be wonderful if it were true, but it is naive to think that scientists will just believe your model is right because you say it is (I am using 'you' in the general sense - I don't actually mean you). You have to provide evidence in support of your model, and that evidence needs to be better than the evidence for the Standard Model before anyone will prefer yours.

That means that you have to do as well as the Standard Model in predictions like the anomalous magnetic moments, which (as you can see in the OP) are very well predicted. This is not actually as hard as it sounds - there are quite a lot of "Standad Model-like" theories out there that do this quite well. But if you want people to believe your theory, you need to do the legwork and make sure it gets these things right!

I was hoping that the post would encourage people to think through their arguments more thoroughly.

I am certainly not a nuclear physicist, but I don't think we have any problem understanding these nuclear properties. Of course, they are using models, rather than the fundamental interactions. Indeed, I am rather surprised you changed tack - one minute you were talking about mesons, while the next you are talking about nuclei.

The more interesting question is, can you explain how the quarks inside the mesons interact?

Severian' date=' is there a website you can post with the math for this? Thanks.

[/quote']

 

It gets rather complicated, so you would be better with a book, e.g. Peskin & Schroder

 

But there are some websites around with incomplete information, such as:

http://theory.sinp.msu.ru/comphep_old/tutorial/node103.html

http://www.fuw.edu.pl/~dobaczew/maub-42w/node9.html

http://pihydrogen.web.psi.ch/papers_html/pip_prop/node10.html

 

This talk is quite relevant to the subject matter too:

http://www.slac.stanford.edu/econf/C040802/lec_notes/Chivukula/Chivukula.pdf

We already have a perfectly good model for predicting the pseudoscalar meson masses. QCD does just fine. It may be a little difficult to calculate anything with, but it gives a hell of a lot more understanding than "The pseudo meson scale is: 1/8, 1/6, 1/4."

Is anyone else having difficulty with this thread? My posts seem to be being eaten. They are there when I hit reply and look at the previous posts but not in normal viewing mode.

This is a test....

Edit: yes, I can see this one.

It is in the hypothesis that the mass or inertia of the electron is entirely due to its own field; and' date=' furthermore, that the momentum and spin of the particle are momentum and spin of the particles own field. In other words we could put mo=0

The measured mass of the particle is a result of the motion of the initially massless “particle” in an external field. Although this idea appears to be very attractive it is not possible, at the present time, to build a complete theory on this basis. Certainly the quantum effects must be taken into account. [b']But even within the framework of quantum theories the nature of the mass of the particles remains unexplained[/b].

I suspect this is simply out of date, since it was originally writtenin 1960. The hypothesis is not that the mass of the electron is entirely due to its own field - the hypothesis is that the mass of the electron is due to the interaction with the vacuum, which gains a non-zero field content due to the Higgs mechanism. Within this framework, the masses of the particles are understood. We cannot predict the actual masses because the strengths of the interaction are part of the model, but we understand how mass comes about.

Extract from “The Elegant Universe”.

Because string theory has no foundation in fact, it does not meet the criteria that defines science and is only correctly defined as philosophy (not science).

I think this is a slightly extreme viewpoint, but I have some sympathy with this view. However, since a well defined string theory could in principle make predictions it remains science - just because we are too stupid to work out what these predictions are is not the fault of strong theory.

Writing in "Quantum Physics, Illusion or reality" Alastair I.M. RAE of the Department of Physics at the University of Birmingham states that Quantum physics is about "measurement and statistical prediction". It does not describe the underlying structure that is the cause of quantum theory.

This is again out of context, but I think he is pointing out that Quantum Physics is not the basis of our fundamental theories - Quantum Field Theory is, which is a completely different thing.

This is confirmed by Richard Morris in "Achilles in the Quantum Universe" from which I quote:

"They (physicists) feel a complete explanation of the subatomic world will not have been attained until it is known why particles have the charge, masses and other particular properties they are observed to possess".

A quote from a non-physicist with an axe to grind is not good evidence.

I feel that further progress will not be made until we have answered the question why? that is what my paper starts to do; it connects experimentally observed fractional measurements with theoretical mass and charge via a proposed wave structure.

And one could exqually well ask 'why?' for your 'proposed wave structure'. If you can explain the masses of the particle via some other hypothesis, you will still have a hypothesis which is unmotivated. If you truely want to be able to derive masses with no remaining 'why' then you have to have no hypothesis in the first place, which is logically impossible.

lucaspa: I don't dispute any of that. String theories do indeed have particles in them with masses which correspond to vibrational modes.

The last equation in your quote from the second link which didn't come out was [math] J = \alpha^\prime M^2[/math], so we can relate the mass to the spin.

For spin zero (J=0) this gives M=0, or massless particles. For J=1 we get [math]M^2 = 1/\alpha^\prime[/math]. Remember that [math]\alpha'[/math] is the string tension, so this is predicting Planck mass particles.

To be honest, I am getting confused while typing this, because I think this should imply that only the scalars are massless, but I was expecting to have all particles with a massless mode. I was then going to provide them with small masses via compactification (which is discussed in the second link you gave).

I am also slightly confused as to how the above equation can lead to the tachyonic expression [math]M^2 = -1/\alpha'[/math] since this seems to require J=-1.

Could he be meaning [math]J_Z[/math] when he says [math]J[/math]? That would explain it... Sorry, I am no expert on String Theory.

Anyway, String Theories, while having particles with mass in them, are not predicting the masses of the particles. You can't sit down and work out the top quark mass for example, because it will be highly dependent on how you perform the compactification.

I thought that string theory started a particle off with having the planck mass' date=' and then via quantum fluctuations most of that mass is cancelled out, leaving the remainder as the total mass.

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No - that is not right. That would be true of, for example, the Higgs boson in the Standard Model, but sting theory have inbuilt supersymmetry (this is the super of superstrings) which makes the quantum fluctuation cancel among themselves.

 

 

Also - and sorry for being another pest in this thread - but how exactly does the Standard Model of particle physics determine *why* particles have the mass they do. I was under the impression that the SM just takes these arbitrary values as a given and basically ignores the underlying reason, or am I wrong

 

As I said earlier, the mass comes directly from the strength of interaction of the particle with the vacuum. However, the arbitrariness is that our model does not predict what these strengths of interaction are, so we have to postulate the right strength to get the right mass. So we have no reason, for example, for why the top quark is so much heavier than the electron.

I have already quoted Gross; Barut' date=' Veltman and others say the same thing that there is no connection between SM, QT and what we observe. Strictly speaking SM and QT are philosophy not science.

[/quote']

 

This is such complete rubbish. The Standard Model makes very clear predictions which are very well tested. It is most definitely science.

 

No one understands what this means.

 

I understand what it means. Why don't you?

Acutally' date=' String Theory does all of these. Defining mass in non-mathematical terms is simply convenience and involves translating the language of mathematics to English. ST says mass is the result of vibration of strings. Thus mass exists because strings vibrate and the vibration is the cause of mass. You need to read more on String Theory.

[/quote']

 

I would dispute that. String theorists have never been able to predict the masses of the particles. If the masses of the particles were really coming from the vibrations of the string then they would either all be massless, or have masses of the Planck scale. To get around this, string theory asserts that the particles we see are the massless modes, but that there is some additional (unknown) mechanism with causes a slight symmetry breaking, making the masses non-zero. That is certainly not a prediction, and the contribution to the mass is not the energy of vibration.

No one theory accurately predicts mass but' date=' several different concepts of mass allow prediction to be made providing the right concept for that particular method is used. As a result ST cannot define mass in non-mathematical terms. It does not tell us [b']what[/b] mass is or why mass exists; or what is the cause of mass.

The inability of the Standard Model to predict the masses of the fundamental particles is a failure - or at least shows that it is incomplete. I know of no model which can predict them though, so I have nothing to replace it with. However, the Standard Model does tell us what mass is and why it exists, and even gives us a cause for mass - it is an interaction of the fundamental particles with the vacuum.

I challenge you to explain in non-mathematical terms why some particles have zero charge and what happens during the conversion process.

Why should I do it in non-mathematical terms? That is like refusing to pay your tax bill unless the government can explain your tax bill without using numbers. The fact of the matter is that some particles have zero charge because they are trivial representations of the symmetry group U(1) - does that count as mathematical? It probably does, but your inability to understand what it means does not make it wrong.

My theory does not predict charge but it does explain why the allocation of fractional charge to quarks is wrong.

Why is it wrong? It fits the data.

Surely the greatest need is not for a better predictive theory but for a theory of explanation. It should tell us what mass and charge really are' date=' [b']why[/b] do some particles have zero charge, how do some zero charge particles convert to two opposite charge particles. At present we can predict but not explain. Surely a new theory should not simply be more attractive, or predictive, or better, but, its priority should be, to improve to our underderstanding of current theory.

If your theory could predict the masses and charges then it would be more predictive, so more desirable.

Note that we do understand (on some level) why some particles have zero charge and how some zero charge particles convert to two opposite charge particles. This is part of the Standard Model.

In the meantime please note you do not use quantum entanglement or such non-classical explanations here.

Quantum entanglement is just the interference between different quantum states. The calculations of corrections to g-2 do include all such interference effects (even though I didn't go inot the calculations in general). Note that you have to use Quantum Feild Theory of course, since QM really only describes one particle moving in a potential.

The Standard Model is not flawed' date=' it does however, lack a complete interpretation. There are two possible solutions to this shortcoming-

a) an addition to the existing theory or,

[/quote']

 

I agree, and I think this is the way forward. The SM makes so many good predictions that we should build on it rather than replace it.

 

b) a new theory that underpins current theory and allows (or gives rise to) a complete interpretation of ST.

 

Presumably ST is 'string theory'. Again, this is holding onto the SM - no string theorists are suggesting that the SM is wrong. They hope to demonstrate that the SM is a low energy limit of string theory. That way, you keep the nice predictive features of the SM, while explaining some of the 'why's with string theory. This is not really any different from (a).

 

So (a) is unlikely to produce results (there have been many failed attempts) because we do not need more predictive ability, what we do need is to know ‘how’ and ‘why’. For this the most likely solution is to be found following the course set by (b).

 

I disgree. There are plenty of new physics theories out there which build on the SM and will be testable soon. A lot of these are actually inspired by string theory's low energy limit in fact.

 

Fortunately, shortly after the rule changes, I was able to produce something suitable for peer review where it has been for the past four months without a decision.

 

If you have something to be peer reviewed then that is great! My post was not to discourage this, but to encourage people to think through their ideas before making a fool of themselves? So before you put yourself up for public ridicule (which is what all new theories are subjected to (Einstein's included)) you have to ask if it makes reasonable predictions for things that have already been tested.

 

For example, if it is a quantum theory, does it describe the motion of electrons correctly? Does it describe electromagnetism? Does it get the correct value for the magnetic moment? (I was being a little tongue in cheek with my first post - I don't expect you to have it calculated to 10 significant figures, but it should agree with 2 to a reasonable approximation.)

 

If it is a theory of gravity, does if have newtonian gravity as its low energy limit? Does it predict the correct perhelion of Mercury?

 

If you have a theory which passes these sort of tests, then we will be very happy to hear aboiut it. If it doesn't pass these tests then surely it is already wrong, and a lot more 'wrong' than the SM. Putting up a theory for peer review which you already know is wrong is asking for public humiliation.

Yes, a PhD is all about research. They do supervised research so that they can learn how to do unsupervised research. I would never trust a grad student's calculation without checking it though (no offense to grad students).

Usually if there is a mistake in a calculation it is really obvious - you find an answer with the wrong properties. But even if a mistake goes unnoticed, it doesn't really matter. A false calculation will never agree with the data (unless the mistake is very small) so you will find a discrepancy with data, and the first thing you do (or someone else does!) is check the calculation.

So then we can be fairly sure that all the theoretical physics results and calculations are cross checked ? I doubt this because most PHDs who are then the ones capable of controlling all the fine details are working on new theories, new results and new papers.

Heh - no. A PhD is research done by the superviser under particularly arduous circumstances.

My question is actually how on earth can any normal person hope to completely understand and calculate things as hard as quantum electrodynamics ? The theory is hard' date=' the calculations are harder and in many cases very few scientists can even cross check many results, you need a supercomputer and need to work at CERN or with an equipe. At this point how much can we really trust the results that are being given to us since it becomes increasingly difficult to REALLY control them ?

[/quote']

 

They are not that hard! I do particle physics calculations as part of my job and I have never used a supercomputer. The only need for supercomputers in particle physics is in lattice QCD, where the strong interaction is modeled on a space-time lattice. Most calculations are recalculated by other groups, but even if they aren't there are a lot of checks which can be done. The analytic expressions must have certain properties (like gauge invariance) which would be removed by a careless mistake. Mistakes are made in the literature all the time, but they are corrected quickly and it is rare for mistakes to remain for long.

 

How many years of studying tensors and integrals and all are necessary ? How smart in the technical sense must a person really be ? It has always been a question in the back of my mind. Thanks for any clue.

 

Well, simple Feynman diagrams calculations are done by our final year undergraduates, so it doesn't require that much training to get started. To work in the field and publish papers you really need to do a PhD. To get a permanent faculty job you need to have done a few 2-year postdocs. I think perseverance if more important that hyper-intelligence. No physicist understands everything, so we are all still learning.

To really understand the Standard Model, you really need to understand Quantum Field Theory. The best book on QFT that I have seen is called "An Indtroduction to Quantum Field Theory" by Peskin and Schroeder. It starts off quite advanced though.

What level are you at? Would you understand this:

http://www.phys.ualberta.ca/~gingrich/phys512/latex2html/node1.html

or is that too advanced?