Hans-G> How many different types

You may count the number of observed elementary particles in the listings of the Particle Data Group (about 1000(?)). The Standard Model does a decent job in explaining everything there, and their dynamical properties. With a rather impressive ratio between predicted properties and model input assumptions.

Just like nuclear physics does a decent job in explaining the chart of nuclides as compositions of protons and neutrons, interacting by exchange of pions and rho-mesons. And like atomic physics does a decent job in explaining the periodic table of atoms in terms of electrons bound to a charged nucleus by Coulomb forces. And so on upwards...

So there is no need to remind anyone about previous successful approaches; they are constantly being re-applied. But each such attempt leads to a package of predictions, where the whole package has to be accepted or rejected (when the predictions fail to be verified).

A puzzling feature is the 3-fold replication of spin-1/2 "matter" fermions in the Standard Model.

http://www-pdg.lbl.gov/2016/listings/contents_listings.html

In the standard model, rather than type of matter, there are symmetry groups and the associated quantum numbers. The basic (gauge) group is SU(3) x SU(2)L x SU(2)R x U(1) (in addition to the Poincaré group, including the SU(2) group of spin.) The particle states are then basis of a representation space of this group. For example the electron and the neutrino are two different state of isospin of the same particle, while the weak bosons live in another representation space of the isospin group SU(2). What are nearer to types of matter are additional quantum numbers like the lepton and baryon numbers, for which there is no associated symmetry group. Unification is the endeavour of providing a larger group to accomodate them. That has failed up to now, but we can't yet say whether it is really a deadlock. Beyond the standard model, there are various theories with subconstituants of the elementary particles, but none of them are convincing.

Dear Christian!

I tend to your answer resp. opinion. But there is a unknown truth behind it.

It is to easy to me that particles are only certain amounts of energy in different forms resp. energy poured into shapes. How are the energy amunts and the "shapes" determined? There has to be a smallest structural element. Compare with the atomic shell: The smallest structural element is the electron. Compare with the energy itself: The smallest element is h. You should consider electrons  and also positrons as the smallest elements of material matter resp. of condensed matter.

My Regards! Hans

Just a question, does the fact that some physicists are satisfied with the current theories forbid other physicists to look for better ones? Is it really what is science? Should this policy be enforced by the referees and the stalwarts of this site?

The original question was about the standard model, so I answered in the framework of the standard model. But it is obviously in need of many improvements, if not a complete overhaul, in particular for bringing some order in the particle menagerie. Physics beyond the standard model is a very active topic of post-modern science, above all superstrings theory. The latter is precisely a way to unify apparently disparate particles through the different vibration modes of a same string. Again, that is not an endorsement of superstrings theory from me.

Dear Christian!

Protons and all other real particles are composed particles. Only electron and positron are not composed, they are elementary particles resp. elementary units. Both of them are the lowest level of material matter (also called as condensed matter). I refer to my paper below.

Many imaginary particles are foundet only by theory. You can read this fact in every textbook. If those imaginary particles should really exist then it would be need for different types of particle matter resp. material matter. Not to mention "dark matter", "matter of black holes" and future inventions by theory. (By the way the Paul-Scherrer-Institut is known for a certain independence. You should work on it.)

Dear Claude!

I am very astonished about the contradictions in physics. The inconsistency of the description of the particle world is one of them. Therefore my question. The downvotes are a sign for a lack of logic and absence of grounds.

My Regard! Hans

Thesis The Reason of a realistic View to Particles and Atomic Nuclei

Dear Hans

If we consider energy as the fundamental componant of all matter, we have to give it a non-isotropic state or form if we want to obtain differents particles with it. The simpliest way to obtain real particles with energy quantum is by a 60° relation (or four axis) because only rational numbers or proportions are allowed. By this way, you will get all the real particles.  The others particles are built on unrationals relations (unrationals proportions or numbers), they exists but they can't have reality; no agreement can be found with a infinite number or a unrational number.  It's a way to resolve the apparent inconsistency in the Standard Model.

Who for God's sake down-voted this question? And why?

If the question is confuse, the poster deserves explanations, not down-votes!!!!!!!!!!! 

It's very UGLY from the part of the down-voters!!!!!! Is there somebody, expert in all the domains?

I systematically upvote answers and questions that have been unjustly downvoted. If this practice spread, the effect of unjust downvote would have many times the opposite of the expected effect.

Martin, you are the one who doesn't contribute to the discussion, I contributed.

In France we say "la première poule qui chante, c'est celle qu'a fait l'oeuf." So could you explain why you downvoted the question? Are you protecting the fame of one of your obligees by making sure no competing theory can emerge?

It have to be acknowledged that scientific research is no longer an occupation of gentlemen. There is censorship on arXiv, abusive moderation in the forums, misdeeds in refereeing, fraud, and so on. No problem with competition? What else? Thus, up-down-voting is bound to be perverted too. I think it would be wise to give it less weight, or even to remove it altogether, since it doesn't live up to its purpose.

Christian,

The issue is as follows: not everybody is competent in every domain. Some people are competent in one domain, but are curious to learn things in another domain. Such a situation should not be discouraged.

The people here are grown up. It's not important WHO downvoted, his name, it just seems a wrong deed. Downvotes should be used in severe cases, and there were such cases here: e.g. people who insulted those who disagreed with them.

On the other side, there is nothing wrong with people who try to widen their knowledge, or, make a proposal and are asking for opinions.

Best regards! 

Of course this question have strayed, but who has given substantial input to set up himself as judge? Not the ones that are only able to issue a "everything is fine, the current theories are an unprecedented success," it's futile. Not either the ones who come with ideas so strange that they can't be worked out, it's futile too. Those answers are noise, as well as ethical rant.

In the same spirit, there are places in RG that are better suited for self serving hype. Many people have assimilated the main modern theories, but much less people are able to have original ideas that could lead to some advance. Thus if it is only to boast your knowledge, we can do without. If it is to sincerely help, it is welcome.

Truly said, fundamental science today is facing an unprecedented crisis since at least hundred years. Electrogravity: failed. Supersymmetry: failed. Grand unification: failed. Decoherence: failed. The measurement problem hasn't yet received a satisfactory answer, neither the generations puzzle. Quantum field theory diverges. String theory and quantum gravity are bogged down and give no result that can be compared with experiment. Even cosmology is jeopardised: dark matter and energy, inflation, red-shift of the quasars that contradicts the expansion of the Universe.

And what do we hear? "Tout va très bien Madame la Marquise." We have numerological accuracy, the theory makes a decent job, we soon have a theory of everything. And, censorship isn't really censorship, blacklisting isn't really blacklisting, the major repository isn't really major, perversion isn't really perversion. In addition, original ideas are down-voted, and mediocre teams are patrolling RG for preaching this catechism and bullying dissonant voices.

It's not out of indelicacy that ethical concerns are raised, we are really fed up of a situation that gets worst and worst, and it is high time that we put a stop to it, even if it isn't the best place for that. We claim the right to think and to communicate without any interference, without being continuously evaluated, judged, belittled, despised, suspected, or ostracised.

Yes, Christian,

you are right. I would consider your suggestion of posing such a question, but I am affraid that it won't interest people. Some people would continue to be positive and others, about which I won't add here additional bad opinions, would continue to do what they like to do.

Now, I'll add something about the question itself. I noticed that you asked by what is a proton bigger than a positron. It is bigger in the sense that we can split it, by investing a certain amount of energy, and we find that it is a composite particle: quarks, gluons. However, if one invests the same amount of energy, one won't split the electron.

Of course, investing much more energy, by orders of magnitude, it's likely to split the electron too. But, what we would find would be indeed the constituents of the electron, or the form in which the energy invested by us would organize itself? Look for instance at the beta emission by some unstable nuclei. The nucleus does not contain electrons.

This is why the question whether the electron may be indeed one of the elementary building blocks in the nature, seems to me interesting.

Aye! Claude Pierre,

In which sense do you think that "decoherence failed"?

Decoherence is just a part in the process of macroscopic measurement of the wave-function. It is not the final part. So what?

Sofia, the theory of decoherence only give a diagonal density matrix. That's just a mathematical trick for calculating the quantum probabilities in case of entanglement, with a random environment or other. Decoherence fails just like the Heisenberg microscope fails to solve the measurement problem, contrary to what was claimed. You only are the victim of an unfair knowledge transmission, where the watchdogs of orthodoxy are given privileged means like arXiv, and above all the refereed journals. They are trying to invest and infect RG too, we must keep vigilant.

There is no electron in a nucleus, but in beta decay no electron leaves the nucleus! An electron-antineutrino pair does, and the neutrino is an electron in a different isospin state. In the nucleus a quark changes isospin state too, so that everything is conserved.

In the not yet rejected theories, a quark remains different from an electron, all the grand unification theories that were developed to make them different states of the same particle have failed. That's one more unsolved problem that is hidden under the carpet.

Christian, a fermion is a particle with half integer spin (electrons (e, mu, tau,) neutrinos, quarks (u, d, s, c...,) baryons (nucleons, strange baryons, charmed baryons...),) then the fermion is a larger class than the electron.

Claude Pierre,

You say,

==> "the theory of decoherence only give a diagonal density matrix."

Yes, of course, but what describes this diagonal density matrix? It describes the observed particle. The question is, does the measurement process, the interaction with the measurement apparatus, involve only the observed particle? Doesn't it involve much more components? We should study the WHOLE system, not only the observed particle, and all along the process. Up to a certain point the evolution is unitary, i.e. the total wave-function of the observed particle and other involved components, is still a wave-function, just with much more particles. But there follows a part of the process in which the things begin to behave differently.

I'd like to invite you to have a glance at my project

https://www.researchgate.net/project/Can-we-explain-the-collapse-of-the-wave-function

Maybe you'd like it. I acknowledge that it goes slowly. I didn't reach the step of which I told you above. But, it will come.

(By the way, I liked the proverb with the chicken, I'll remember it.)

Best regards!

"...the structure of the particles zoo based on something simple."

Yes! But not in the present theories. I was very extremely surprised that there is a possibility to describe the particles only with the two dual particles electron and positron. It was not my intention to refute the present theories. But I am more and more convinced that there is no other way. The reality is foundet on the duality of those two particles and not on dozens of  particles invented by a inconsistent and contradictionary system of theories.

If you analyse particle dacays and interactions unbiased then you will see at least only electrons, positrons and energy (as the other half of matter). Light particles as muons, pions, omegas etc. were synthesized in electron-positron collisions at high energy. Analysis and synthesis are done - so what physics is waiting for?

The consequences are clearly visible: The experimental results of the last century are reliable, but the previous theories are worthless.

The actual problem is always the same also in science: Nothing can happen what isn't allowed to happen.

There are experimental evidences against SU(5) grand unification, the lifetime of the proton, and that is also valid for most of the other grand unification theories, since they must postulate transitions between leptons and quarks. This genuine knowledge must be trumpeted, not hidden under he carpet. Supersymmetry have absolutely no experimental confirmation, although it is ubiquitous. Spontaneous symmetry breaking for predicting hyperheavy supersymmetry partners has no credibility, and anyway predict further Higgs-like particles that have never been observed either. This genuine knowledge must be trumpeted, not hidden under the carpet. Any subsidy in those domains must be immediately cancelled, that's one of the reasons why censorship wages on arXiv and many other places. This practice is unacceptable and must stop immediately.

@Christian: The term "conspiracy theory" sounds like a killer argument. Save yourself for real arguments.

@Martin: You can probably read therefore I refer to my paper.

The standard model disproved itself. The "quarks" are unproven par example. The LHC-experiment was absolutely unsuccessful. It was possibly the most expensive eperiment of all times. Can you call me a direct proof of "neutrinos"? All of them are indirect. Always Reines and Cowan have neglect to discuss other causes of their observations in the Savanna-River-Experiment. But this is a necessity in each evaluation of experiments. As I said: Nothing can happen what isn't allowed to happen.

Sorry, present theoretical physics is in such a disastrous state that it is impossible for one or two generations to return to a real base.

Hans-G> there is a possibility to describe the particles only with the two dual particles electron and positron.

You have a model where the proton (observed stable with mass 938 MeV, lifetime > 2.1 x 1029 years) is made up of pi+, pi-  (mass 140 MeV, lifetime 2.6 x10-8 secs) and mu+ (mass 106 MeV, lifetime 2.2 x 10-6 secs), where pi+, pi-are made up of 3 electrons/positrons (mass 0.511 MeV) and mu+ is an excited positron.

* How do you explain the mass of the proton, much larger than the sum of its proposed constituents?

* How do yo explain the extreme stability of the protons, almost 40 orders of magnitude larger than its constituents?

* How do you explain the results of electron-proton scattering experiments, which probes the internal structure of the proton?

I could repeat these three question for 100's of other observed particles. And next ask for explanations of the absence of other combinations which can be constructed by your scheme. A realistic description of elementary particle physics must be able to answer such questions to some degree of accuracy. I.e., predict what is observed and not predict what is not observed (and within experimental reach).

The Standard Model has done that for about 40 years. One may rightfully claim that it is not very pretty. But the attempts of improvement do not look much better, and are not convincingly supported by experiments. At least not yet.

The idea that the second and third generation fermions are excitations of the first generation sounds reasonable. It has been thought before.

Thesis The Reason of a realistic View to Particles and Atomic Nuclei

Claude> The lifetime of the proton is greater than 10^32 years.

The (surprisingly low) number I used is taken from the Particle Data Group, who writes  'The limits here are to “anything” or are for “disappearance” modes of a bound proton (p) or (n).' 

Christian, and for that you are absolutely right. That's why no theory should be imposed by any mean, neither authority, or censorship, moderation, personal attack etc.

I am not across the board, I acknowledge many virtues in the currents "validated" theories, but I doesn't consider them as catechism, and I keep my critical thinking by myself, since that is the only way to make some progress. Nevertheless, I understand why some people are so, and it is because of the arrogance and overbearingness of people that have stakes in some part of it.

Claude> Olausen, ...

???

@Kåre: Counterquestion: How explains the current theory all your questions? Par example have the unproven "quarks" (u,u,d) a theoretical mass of about 9,4MeV. One quark has at least to be stable but there is nothing observable ...

- The most particle mass is accumulated energy (you can name the "container" for this energy elementary and substructural capacitors). You can imagine that same particles do not have evan the same mass resp. energy --> invention of the neutrino by Pauli.

- The more or less stability of particles is structural caused. The stability of the proton is caused by three charged particles and the possibility of a steady exchange of elementary charged particles always into the same structure. Charged pions and charged kaons have also a similar structure with three charged particles --> long lifetime.

- The deep inelestic scattering showed three sub-particles within the proton. Three particles became visible to my surprise during my analysis. In case of the neutron is the electron scattering impossible.

- The duality of electron and positron and their combinational structural compositions allow much more particles as the quark-hypothesis. The PDG described only a fractional amount of all particles. There is no need to invent future even more "quarks". And you can invent every particle you want: sooner or later you will observe a particle close by the prediction and you can proclaim: "Heureka!"

To your calming: The "standard model of the universe" with the earth as centre of the world or universe was for more than thousand years sufficient but also wrong. And Einstein himself was the opinion that the continents would never shift.

Dear Claude!

The lifetime of the proton was calculated based on theoretical assumptions. There is no experimental evidence. Under certain conditions is all material matter unstable: atoms, protons, atomic nuclei.

Compare different pictures of galaxies: Many of them showing different states of explosions in the past. If the density of energetical and material matter reached a certain stage then happens a explosion in the centre of this galaxy. Astronomer have observed gigantic energetic outbursts. At this stage is the change of the shape of the galaxy still unvisible.

My Regards! Hans

Dear users, and especially Kåre

First of all, I have to tell you all that I never learnt Quantum Field Theory (QFT) systematically, s.t. a big part of your arguments about the Standard Model I do not understand. Though, at a general level, it seems to me that there is a deep grain of wisdom in Hans' question. I do not refer here to his article or project, but to the question itself.

Please see: Can somebody imagine how it is possible that a handful of protons and neutrons taken together and forming a nucleus, have, each one, a smaller mass than when it is free? Can you imagine that a handfull of peebles, when taken together and forming a stone, have a mass smaller than when free?

Let me ask another question: a nucleus doesn't contain electrons and neutrinos. Though, it may emit a β ray and a neutrino.

Now, what I see in these facts is a picture as follows: when the internal dynamics of an object as a nucleus, or some unstable particle (e.g. a neutron), allows passing to a state of lower energy, what is emitted is, essentially, ENERGY. Due to some laws of QFT (in which I am not so competent), in combination with the different conservation laws (of energy, momentum, spin, etc., etc.) this energy cannot be emitted just as a block of matter. It arranges itself in sets of building blocks: electrons (positrons), quarks, pions, mesons, etc. The quarks are unable to stay free, s.t. they "eat" other building blocks around themselves, generating composite, though much more stable building blocks.

Now, I return to Kåre's question

==> "How do you explain the mass of the proton, much larger than the sum of its proposed constituents?"

Which constituents Kåre? Does a proton contain a neutrino? When we break a proton we invest energy. This energy plus the proton rest energy mc2, passes into building blocks allowed by the conservation laws.

I try to think what zoo-park we'll see when we will succeed to break an electron. But, does that zoo-park really exist inside the electron, or is an arrangement of the energy invested plus m0c2 of the electron?

To everybody: I don't make theories here, I am not a specialist in QFT. I just stress some issue in the question of Hans. 

* How do you explain that the masses of the electron and of the muon are different while these particles differ by nothing else?

* How do you explain that the mass of the neutron is larger than the one of the proton in spite of the electromagnetic self-energy?

* How do you explain the result of photon-photon scattering in spite of the superposition principle?

* How do you explain the mass of the electron while gauge symmetry forces it to be zero?

* How do you explain the extreme stability of the electron while the neutrino has a smaller mass?

Hans, a first estimation of the proton lifetime has been performed in the 1980's 1990's, up to the rejection of the SU(5) grand unification theory. That has been done in a huge underground water reservoir and with a huge amount of money. Today, no decay of the proton has been observed, and all in all its lifetime must be greater than 10^34 years (10^23 times the age of the Universe!) That's an experimental value. There are predictions with various theories (including the standard model,) but they typically give a smaller value. In summary, "To date, all attempts to observe new phenomena predicted by GUTs (like proton decay or the existence of magnetic monopoles) have failed." https://en.wikipedia.org/wiki/Proton_decay  In fact, the very failure of the Dirac monopole heralded the subsequent failures, because after the success of the prediction of the positron, Dirac thought that every mathematical structure must have a counterpart in the physical world, and the physicists servilely adopted this paradigm.

Hans> Par example have the unproven "quarks" (u,u,d) a theoretical mass of about 9,4MeV.

The mass of a free quarks are expected to be infinite; this expectation is founded on experiments and QCD calculations.

Hans> The most particle mass is accumulated energy

Yes, for hadrons the mass mainly seems to be due to kinetic energy of its constituents. This observation was used to formulate the bag model, which works quite well. 

Hans> The more or less stability of particles is structural caused.

Less than more. One needs a dynamical theory to explain how the constituents bind together; the same theory must also explain how they interact in f.i. scattering experiments. It is easy to dream up models; it is difficult to construct a model which works for all measured phenomena (or, in less certain cases, cannot be disproven). The QCD+quark theory of hadrons took considerable time and efforts to develop.

Hans> The deep inelastic scattering showed three sub-particles within the proton

At least not seven, as in your model. Deep inelastic scattering of electrons and neutrinos on protons also give information about the electric charges of and weak interaction properties of the constituents (the few-MeV quark masses you mention refers to such properties). And about the gluon fields which keeps the fermionic constituents together. And a lot of additional data. The constituents of the proton cannot be electrons and positrons.

Hans> electron and positron and their combinational structural compositions allow much more particles as the quark-hypothesis

I suspect so. Particles which don't exist. One long-time problem of the quark model was to explain exactly the right spectrum of particles (with the right properties).

Hans> The "standard model of the universe" with the earth as centre of the world or universe was for more than thousand years sufficient but also wrong.

It retrospect one can say that it was more inconvenient than wrong. But the old world view was to a large extent based on assumptions and prejudices instead of accurate observations. Likewise, any alternative model of elementary particles cannot be based only on assumptions and prejudices, it must also explain all data already explained by the Standard Model.

40 years of seemingly futile efforts indicates that it is very hard to come up with acceptable alternatives. Without experimental guidance from the LHC experiments (during the next couple of decades) the whole field may very well come to a halt.

Unless someone comes up with an extremely good idea in a direction nobody has thought of before...

Kåre, Martin, Claude Pierre,

did you read my post? It would spare part of the arguing here.

Claude Pierre: EPR type experiments are NOT WRONG. They just discard some theories of hidden variables or elements of reality. They limit the set of possible explanations of the way the entanglements work.

Claude> How do you explain that the masses of the electron and of the muon are different while these particles differ by nothing else?

I have already mentioned this as a puzzle a couple of times. It is now more than 80 years since Rabi's famous quip, "Who ordered that?". It is natural to suspect that the higher families are some kind of excited states. But that requires some kind of substructure, which has not been observed. The existence of three fermion families complicates the Standard Model, and makes the supersymmetric extensions of it plain ugly.

I am sure anyone providing an acceptable explanation for the three families will be invited to Stockholm some December.

Claude> How do you explain that the mass of the neutron is larger than the one of the proton in spite of the electromagnetic self-energy?

There are two theoretical contributions: The proton charge contributes -1.01 MeV to the difference. The (current mass) difference between d and u quarks contributes 2.52 MeV. This leads to a theoretical difference of 1.51 MeV, quite close to the observed value of 1.29 MeV.  The numbers are from reported ab initio lattice QCD calculations, cf. the links. 

http://science.sciencemag.org/content/347/6229/1452

https://arxiv.org/pdf/1406.4088v2.pdf

Thanks Martin,

Well, it's very late in my country, I'll think about your explanation tomorrow.

Claude> How do you explain the result of photon-photon scattering in spite of the superposition principle?

I am unsure what is meant here. But vacuum polarisation in QED makes classical electrodynamics in vacuum a little bit non-linear, as described by the Euler-Heisenberg Lagrangian.

Claude> How do you explain the mass of the electron while gauge symmetry forces it to be zero?

It is modelled by a gauge invariant Yukawa coupling to the Higgs field, which leads to a mass term caused by the Higgs mechanism. The value of the coupling strength is adjusted to give the observed electron mass, so there are no predictions in this.

Claude> How do you explain the extreme stability of the electron while the neutrino has a smaller mass?

By charge conservation. In addition to baryon conservation, which prevents the proton from decaying, and ultimately ending up as positrons which would annihilate together with the electrons.

How do you measure the mass of a quark? It depends on the energy of the probe. In addition, theoretically it depends on the coupling with the Higgs field which is a free parameter. Anyway, most of the mass of a nucleon is not given by the constituent mass of the quarks, in particular the binding energy is very large. That's a sledge of hand, not physics. To describe a nucleon, a lot of parameters intervenes like structure functions, contribution to the Dirac sea and so on. Quantum chromodynamics is non perturbative, which means that no precise calculation is possible, even if the effects associated to the non perturbativity are roughly verified by experiment. So that the radius of a nucleon calculated by two different methods gives different values. I further mention the EMC effect, that shows that the structure of a free nucleon and one in a nucleus are different, without any explanation.

I say it, if the proton doesn't decay, it is because the quarks aren't fermions, but partial fermionic modes. If we don't see the colour, it is because it isn't a gauge group, but a groupoid. Glueballs, asymptotic freedom, and lattices should be deposited in the department of cinema accessories.

Claude> Quantum chromodynamics is non perturbative, which means that no precise calculation is possible

As illustrated by the paper I linked to above, lattice QCD and large computers are making it possible to an increasing degree. There has been some progress during the last 40 years.

Claude> I further mention the EMC effect

Yes, that is a dirty problem which has not been solved in 30 years. 

Claude> ... it is because ...

Your suggestions here are interesting; can you give any references to more details?

Kåre and Claude Pierre,

Why is a problem the fact that the muon is heavier than the electron? The muon seems to be a highly excited state of the electron, its lifetime is short 2microseconds. It decays, i.e. gets rid of the additional energy and falls to the ground level.

As to the tau, it is much heavier than the muon, i.e. an even higher excited level, and in consequence the lifetime is by far smaller, 290 femtoseconds. The big energy that it can release allows many decay channels. No invitation to Stockholm is needed for that. What would be really interesting would be to find a model for these particles and predict the height and width of these excited levels. Since the lifetime is known, the width of the excited level is known.

For me, it is a puzzle why these two are considered an elementary particle and not excited states (resonances) of the electron. I think, maybe naively, that an elementary particle doesn't undergo spontaneous decay, it can be split only by adding energy.

Sofia> a big part of your arguments about the Standard Model I do not understand

There is a good qualitative description at the particleadventure link below.

Sofia> Which constituents Kåre?

I was referring to the particle model proposed by Hans, which I described briefly in the top of that post of mine, and which is fully described in the link at the bottom of it.

I think the rest of your questions have already been answered by Martin.

http://particleadventure.org/index.html

Sofia> it is a puzzle why these two are considered an elementary particle and not excited states (resonances) of the electron.

That more-or-less requires the electron, muon and tau to be made of something else. But when you start combining smaller pieces into bigger composites, you can easily end up with too many or wrong types of composites (such that are not observed), interacting in the wrong manner. So it becomes a problem of finding the right building blocks. Next, if the electrons and muons are composed of smaller pieces, that ought to be experimentally observable if you look close enough.

One can imagine alternative ways to make resonances, but that is likely to destroy the predicted (and verified) value of the electron magnetic moment (which is successfully calculated under the assumption that the muon is a genuine elementary particle).

And, it is not only the siblings of the electron which must be explained, but also the neutrino sisters, and the quark brothers and sisters.

I think the attempts at substructure ran out of steam at some point in the 80's. Perhaps because nothing workable could be found (or perhaps because everyone started to work on superstring theory).

Martin> I just wanted to mention that the idea of composite fermions is not completely abandoned yet

Sounds interesting. Personally I find Rabi's 81 year old question more urgent than the question of naturalness (which is not that naturally solved by supersymmetry any longer). Why the heck do we need three fermion families? To break CP?? 

I find it unhelpfully and even counterproductive when a question is dominated by guardians of the pure doctrine. Such peoples talk new ideas and unconventional solutions down. They should pray their dogmas in the ivory towers of theory.

The EMC effect contradicts the calculus of QCD. In a normal situation, that leads to the rejection of the theory, not in the "Church".

Hans> Such peoples talk new ideas and unconventional solutions down.

It should have become clear by now that your idea of making particles from smaller entities is not new at all. It may continue to be a good one, but it may also have been reused so many times that nature has gotten sick-and-tired of it, and expect us to come up with something really new and unconventional.

In a thread classified as condensed matter and particle physics, you should be grateful for factual information from these areas. From my own experience and observations, I don't think it is healthy in the long run to walk around lulled into of fog of wild dreams.

Martin> Abandoning QCD because nuclear physics is not working well sometimes seems to me a bit premature.

Yes, but I think this seemingly mundane problem should be given increased attention (compared to the enormous intellectual investment in f.i. string theory), since it may lead to increased understanding of how nuclear physics and QCD overlap. But it is probably a very hard problem, which will bring little fame to its solvers. One may have to wait until ab initio lattice QCD calculations can be done on f.i. 9Be.

The situation is not very different from condensed matter physics. F.i., 30+ years after the discovery of high-Tc superconductivity, a convincing explanation seems to be lacking. One has not abandoned condensed matter theory because of that.

Martin> Some people even say that this is just how it is. There is no deeper explanation.

That reminds me of Keplers beautiful theory of the six planetary orbits known at his time, described in Mysterium Cosmographicum, based on the five Platonic solids. It almost worked, but who will try to explain the ratio of planetary orbits today?

In another 500 years, will some current questions of particle physics turn out to be like that?

@Kåre, and @Martin,

==> (Kåre) "when you start combining smaller pieces into bigger composites, you can easily end up with too many or wrong types of composites (such that are not observed), interacting in the wrong manner. So it becomes a problem of finding the right building blocks."

==> (Martin) "The known fermions then could be superpositions of fundamental and composite objects."

Again, I appologize that I am not a specialist in QFT and for the moment I am occupied with my project on the collapse. But, I'll take an example from a domanin in which yes I am competent: resonances.

An excited level of, say, the hydrogen atom, does not contain a photon, an electron, and a proton. The wavelength of the photon is usually too big to fit inside the atom. Instead of that, the building blocks of the excited H atom are: proton, electron, kinetic and potential energy of the internal dynamics of the proton and electron. And, by the way, the total energy of the H excited atom is still less that the sum of the masses of the two free particles.

Now, the electron is not just a sphere containing electric charge. The fact that it has a magnetic momentum shows that there exists some internal dynamics. What if this internal dynamics admits excited states?

Can't we have with the muon and tauon a similar tableay as with the H atom? Can't it be that the electron is the ground state of the muon and tauon? Can't it be that the muon is an excited state of the electron, containing the electron plus potential and kinetic energy, and de-exciting by the emission of νμ and (anti)νe which maybe didn't pre-exist in the muon? Similarly for the tauon.

Of course, at present we don't know the internal structure of the electron, otherwise we could calculate the excited states as we do for the atom, and as we do for excited nuclei. However, the basic principles of a resonent level is the same for atom and nucleus. Why should it be different for unstable so-called elementary particles?

No, vacuum polarisation is a tale. Empty space is empty, and is precisely called empty because of that (the explanation of the Casimir effect isn't the claimed one.)  The photons don't scatter, like is said, but the particles created out of their energy do. The Maxwell equations are strictly linear (Born Infeld theory failed,) only the interaction term with matter is not. This non linearity have never been investigated, since that is mathematically impossible until now. It has been coped out by the inconsistent and unjustified statement that a particle can't interact with itself, while at the same time the concept of individual particle doesn't exist in quantum mechanics and quantum field theory.

Similarly, deep inelastic scattering off nucleons need not be what is said, that's just a metaphors that until now has worked, but that have been refuted by the EMC effect.

Given the predictions of QCD and the data of EMC, it is possible to calculate the distribution of the Fermi motion in a nucleus, at least by a numerical procedure. Has that been done? Does it give realistic results? I think these questions should be answered before accusing nuclear physics, that is anyway already known to be a very difficult science with very vague results. Deep inelastic scattering is a cleaner method to address such problems. That's a further example of the action of the Cerberus of the Church. Face it, the EMC effect is real. Anyway, whatever the rational, nothing at all can justify that QCD be favoured and other ideas quenched. The solution will perhaps be in one of them, whatever the real or fantasied success of QCD. "Abandon" is their word, concurrent theories can and should coexist.

Sofia> Can't it be that the muon is an excited state of the electron, containing the electron plus potential and kinetic energy

First, one has to make a precise mathematical model of this idea, without introducing substructure. Keep in mind that the hydrogen atom is composed of a proton and an electron, hence it has a substructure of interacting components (which is used to calculate the excited states).

Can one somehow get around that? Maybe. But then one has a radically different model for the electron, muon and tau. Which would lead to a radically different way of calculating contributions to the electron anomalous magnetic moment.  But there is no need to worry about that until later. So (some-)one should just implement the first sentence of the previous paragraph. How? If I knew I wouldn't tell anyone before it was published in a decent journal.

Claude> The photons don't scatter, like is said, but the particles created out of their energy do.

The Euler-Heisenberg Lagrangian is a consequence of such processes, which leads to predicted scattering for photon energies below the threshold for electron-positron creation. The effect is too small to be detectable in available earthly experiments. But one consequence is a modified propagation of light in very intense magnetic fields. An astrophysical observation of this has recently (last november) been reported. With a magnetic field of 109 T, close to the neutron star RX J1856.5−3754. Cf. the first link below.

Claude> This non linearity have never been investigated, since that is mathematically impossible until now.

I don't know what you mean by this. The Euler-Heisenberg Lagrangian has been derived many times, cf. the Wikipedia link below.

http://mnras.oxfordjournals.org/content/465/1/492

https://en.wikipedia.org/wiki/Euler–Heisenberg_Lagrangian

Dear @Kåre,

Let's leave aside prestigious prizes. We just talk, it's only a mental exercise.

So, do you really believe that the electron doesn't have a substructure? We are sure that it is not just a sphere comprising negative charge. Such a sphere, if static, does not produce a magnetic moment. Neither is it a rotating charged sphere - such calculi were done and produced result which don't fit the experiment.

But, I have a belief: the nature is not schisophrenic. (I told this once to the (beloved and so much regretted) Abner Shimony, and he agreed.) If the nucleus of the atom admits resonant levels, so much similar in principle to the atom's excited levels, why should the so-called elementary particles behave otherwise? Look at the proton! How is it built? A substructure of quarks and gluons, with very big masses, kept together by a huge attractive (nuclear) potential energy.

The problem is that we don't know the internal structure of the electron. To split an electron takes energies by orders of magnitude greater than to split the proton (an electron collider?). And probably, we would discover new types of forces.

Again, we just talk.

Sofia> do you really believe that the electron doesn't have a substructure?

No, not really. It is just my impression that this option has been explored unsuccessfully by so many brilliant people, of much more energy and knowledge and ingenuity than me, that it would be futile for me to try. That is a good excuse for being lazy ;=D

Dear @Martin and @Kåre,

The fact that the electron has a magnetic moment doesn't suggest you that there is some internal dynamics? As I said, the picture of a rotating sphere carying charge, didn't work. So, the internal dynamics of the electron should be more complicated. To me, it seems that the photon yes is a particle of which we can say that it has no substructure - but I told you what is my level in QFT.

Now, shall I also say that I am lazy? I am old, that's sure, and what I was able to do a couple of years ago, I can't do now at the same rate. I hope that you too are younger than I. I regret terribly that I didn't learn systematically QFT (when I learnt physics, in my youth, this topic wasn't taught in our department - maybe they didn't have a specialist in this). And to begin to learn it now, no chance in the close future. 

About an electron structure, Paul Ellis showed me an article trying to suggest a structure, it was one or two years ago. I can ask him again, but not soon.

At least, I learn from this debate interesting things.

With kind regards to both of you!

Dear Sophia!

Care and Martin are not young savages but young aligneds. ;-)

To the matter: We have too much mathematical models in physics and too little recognition. As Robert B. Laughlin stated: the world (the reality) is not a mathematical derivation. Therefore I'm strictly against the method to made first mathematical models and then check them what means to adapt the reality to the mathematics. The required mathematics appears from the recognition. Mathematics as a science has it own space of truth and developed itself and it was thousand years ago derived from the reality.

Many scientists are the opinion that mathematics is the way to recognise the reality. You may study mathematics but you cannot study recognition. Therein lies the problem.

My Regards! Hans

Hans> Kåre and Martin are not young savages but young

Thanks a million for the complement; I really appreciate it!

@Claude Pierre, you say

==> "No, vacuum polarisation is a tale. Empty space is empty, . . ."

How could it be that "empty" has an electric permittivity and magnetic permeability?  And further, what about the Dirac sea? It does not exist?

I repeat, I am no expert in QFT, but it doesn't seem to me trivial to deny the Dirac sea, as long as we don't have another explanation for the existence of an electrostatic field between two charges in vacuum. Action at a distance does not exist.

This issue touches the so much controversed problem whether virtual particles exist or not. The existence of the magnetostatic and electrostatic seems to me the simple and convincing argument in favor of the existence of virtual particles.

Kind regards!

Now an answer is flagged because it says some theory is wrong, if it isn't censorship, what it is? That's it, ciao, I have better to do.

The question of magnetic moments is interesting (with an interesting history), because it illustrates one of the hard problems which has to be overcome if one wants to realistically model some particles as made out of others (LEGO-block physics), or being excitations of others. In particular the fact that observed electron and muon magnetic g-factors are so close to two, with explained and calculated deviations, is very constraining.

I want to take another view on the original question, how many types of matter is there, by interpreting "types of matter" as "conserved additive quantum numbers":

* Baryon number is observed to be conserved (to very high accuracy), this is also predicted by the Standard Model (not exactly, but to ridiculously high accuracy).

* Lepton number is observed to be conserved (to very high accuracy). The original Standard Model predicts conservation of three types of lepton numbers (electron type, muon type, and tau type), The observed neutrino oscillations show that these types are not individually conserved, only their sum. It is so straightforward to modify the Standard Model to match this fact that this does not warrant a change-of-name. This predicts the neutrinos to be of Dirac type, which is not (yet) refuted experimentally.

* Electric charge is observed to be conserved (to extremely high accuracy), and is exactly conserved in the Standard Model.

* Color charge is observed to be conserved (to high accuracy), and is exactly conserved in the Standard Model.

* One may wonder about what has really happened to conservation of the weak isospin charge. 

So, to make a LEGO-box model for particle physics one should try to make it agree with these observed facts.

Dear @Martin,

You said "see the attached link", but you attached no link. Could it be that you thought of this link?

https://en.wikipedia.org/wiki/Muon#Anomalous_magnetic_dipole_moment

I quote from it:

==> "The anomalous magnetic dipole moment is the difference between the experimentally observed value of the magnetic dipole moment and the theoretical value predicted by the Dirac equation."

But you say:

==> "The Dirac equation for spin 1/2 particles predicts a magnetic moment without invoking any substructure."

Both quantum mechanics (QM), and relativistic quantum mechanics (RQM) take a particle for point-like when they examine the dynamics of the particle as a whole. In particular, so does the Dirac equation.

QM goes to the internal structure when it examines the internal dynamics of the particle. For instance, in the quantum nuclear theory, QM doesn't take a nucleus as point-like, but takes the nucleons as point-like. But, for examining the internal structure one has to know the components of that structure.

Now, my comments are questions, not criticism of what you say - my bad level in QFT doesn't allow me to criticize.

By the way, I subscribe to your opinion on precize science. We need quantitative calculus. It's not the same when one touches (by mistake) a conductor passing 1nano-Ampere, and when one touches 1000 Amperes.

@Kåre,

I saw your comment about conservation of electric charge, barion number, lepton number, etc. But, look what I saw at

https://en.wikipedia.org/wiki/Gluon#Experimental_observations

==> "Deconfinement was claimed in 2000 at CERN SPS[22] in heavy-ion collisions, and it implies a new state of matter: quark–gluon plasma, less interacting than in the nucleus, almost as in a liquid. It was found at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven in the years 2004–2010 by four contemporaneous experiments.[23] A quark–gluon plasma state has been confirmed at the CERN Large Hadron Collider (LHC) by the three experiments ALICE, ATLAS and CMS in 2010.[24]"

Are you aware of these discoveries?

At a certain (extremely high) temperature and pressure one gets deconfinement, s.t. one cannot speak anymore of conservation of baryon number because the baryons are split.

Now, can you look at the page https://en.wikipedia.org/wiki/Gluon ? There are two diagrams that seem to me strange. On one side there are an electron and positron, and on the other side three gluons. Which conservation laws are here, except for (I assume) spin 1? Souldn't gluons appear in pairs (color and anti-color)? I do not understand what's going there. Would you have a look?

With thanks in adavance!

@Kåre: The emphasis is on the word "aligned" (in German I would say: Angepasster Mensch). Is your avatar as old as your opinions?

Dear Sofia!

With respect to your comment, I do not think much of Wikipedia and also of the evaluations of the experiments strictly according to the theory.

The Wikipedia articles are written by authors with the same conviction as Kåre, Martin et al. If the Wikipedia would exist always in the year 1500 you would at that time never read  about the orbit of the earth around the sun.

The crossover between energy and material matter and vice versa is known only as pair production and annihilation of one electron and one positron. How this mechanism should function with other particles is a resulting question of the initial question. We can be sure that in the whole univere the amout of electrons and of positrons is exactly the same.

My Regards! Hans

Sofia> Are you aware of these discoveries?

I don't claim to be fully updated on everything, but I have chatted a lot with Jens: https://www.ntnu.edu/physics/theoretical/astro

My project meeting today was with a PostDoc whose Ph.D thesis project was oriented around the hard-to-analyse QCD phase transition. And my last article has another former student of Jens as first author. This is an area where the basic equations are believed to be known, but where it is very hard to extract reliable consequences. 99.9% of physics is like that...

Sofia> There are two diagrams

In both cases all the discrete charges I mentioned are zero on both sides of the diagram. For baryon, lepton and electric charges because particles and antiparticles have opposite charges; for the colour charge(s) the story is too complicated to expose here. Colour charge is actually not additive, but behaves more like angular momentum, so I should formally not have included it in my listings (but that would also have been misleading).

Hans-G> The emphasis is on ...

I know we have (slightly) different emphasis, and I know how to correctly adjust for that.

Hans-G> Is your avatar as old as your opinions?

Everything is much older than my ten last opinions about fundamental physics.

Note added: I don't  think it is fair to down-vote Hans on his own blog, for comments which are not that bad. I have up-voted, not because I think the posts really deserved it, but to compensate for what I consider unfair down-voting.

@Martin: >>It is no fun to be challenged, right?

Dear @Martin,

Thanks for the reference on the muon. I see indeed that in predicting the muon magnetic momentum no internal structure is supposed. Though, please tell me, is the muon magnetic momentum equal to that of an electron?

Also, I would be glad if you'd tell me what the muon magnetic momentum has to do with the vacuum hadron polarization. Is that because the muon results from the decay of a pion?

With thans!

Who is the one who down-votes Martin? If somone disagrees with his answers, someone should expose his objects, not down-vote and hide cowardly.