Bob_for_short

Why do you color your texts? There are practical ways of extracting (separating) positrons from the reaction area and using them in accelerators. It has already been done.

You are right, of course. I did not mean "inverting" matter into anti-matter but producing additional globally neutral pairs.

Yes, if the energy is sufficient, hitting a particle with a strong potential barrier may produce particle-antiparticle pairs with high probability, just like in particle-particle high energy collisions.

Acceleration is a movement feature by definition. Gravity can be felt as a force without motion if it is compensated with an elastic force, for example. If we speak of macroscopic bodies, the forces should be applied to each body piece proportionally to their masses. Normally we apply an external force at some point or on a surface smaller than the body size so there arise deformations inside the body. It never resembles the gravity action.

The QED output is the real, physical, dressed particles. Why we, knowing the output, cannot use it as an input? Why not work exclusively in terms of physical entities? Maybe because we just do not have the right idea about them yet?

The discrete space can be imagined as a set of pixels and the discrete time can be thought of as refreshing rate of your screen.

I do not think so. As long as a theory is not physical - its essential elements are non observable bare particles and renormalizations, it is not a physical method. Why do we close eyes on these mathematical and conceptual problems? How can we count on predicting something new if we start from non existent things?

Maybe not religion but obsession of theorists to build a TOE, not less. You know, we theorists, are so clever that can guess everything that exists and even what has not been observed yet, - so powerful we are. We do not need many experiments to build theories. We advance theories and see the experiments via our pattern. That's the right scientific approach. Soon the God's particle will be found and our SM theory patch will be justified experimentally. I really count on absence of Higgs, to tell the truth. That's why I really hope the experiments will make many physicists more sober.

From what I have heard, it is the final particle to make ends meet in SM. They call it a "God's particle" because it can save an otherwise unsatisfactory theory. Higgs boson makes the SM to be a religion with Higgs as the Saviour.

There are things above T=0K that do not feel time: the conserved functions of motion, for example, the total energy, the total momentum, the total angular momentum, etc., that do not change in time despite motion. The listed explicitly functions are well known and are additive in particles, but there are the integrals of motion in CM that are not additive in particles. Their number is equal to the number of initial data, I think.

Yes, of course, because they are classical theories with abstractions and idealizations. For example, CM is about motion of centers of inertia of macroscopic bodies (3 coordinates suffice). As soon as the body information gets "fluctuating", CM fails. Consider the limit of low intensity of light (few photons per second). The body position gets uncertain due to lack of statistics for good averaging. This is an experimental limitation. In such conditions you cannot collect sufficient information about the initial data and predict the body trajectory with CM.

In fact, time flow is not a series of infinitesimal periods but always a series of finite intervals because for a too short interval of time we cannot get sufficient information - information becomes uncertain, unreliable. Take a film camera and try to increase the rate of frames by decreasing the exposition periods. You will arrive at so short expositions that the information on each frame will be too poor or even absent some times (no photons registered on a frame). On the other hand, time serves to follow changes of information on frames, so for certainty the exposition periods cannot be too short or too long.

Quarks were conceived as bound entities, let us not forget it. So whatever energy is used to "separate" them, they will always come together. It is popular but not correct explanation because it may still imply some probability of creating separated quarks in pairs. In fact, the only "explanation" is the quark definition as charged species in bound states. In other words, gluons are always meant to be inplace. Unfortunately a "gauge" way of introducing quarks and gluons (via "gauge covariant derivative") makes an illusion that quarks may be free, at least theoretically - if we neglect the gluon field. If we introduce quarks as quasi-particles in compound systems, there will be no question about their observing as free particles. This way is quite phenomenological and physical. Very simplified and comprehensible model is given in my "Reformulation instead of Renormalizations" paper (http://arxiv.org/abs/0811.4416).

Unfortunately we see the things via pattern of our theories. And our theories have tendencies to be TOE because it is our aspiration and ambition. If Higgs does not exist, that will mean W-boson and all that do not exist either, at least in a way it was meant to be - as gauge fields. When a model is complicated and contains many "free" parameters, some experimental data can be "predicted" (fitted) and this creates an illusion that the model is right. With years we become hostages of our beliefs in our models and close eyes on obvious failures. For example, the idea of elementarity is contradictory to the idea of interaction because there are "elementary" things that are in permanent interaction (non separable). It is better to speak of a compound complex system with elementary excitations rather than of elementary and separable particles (electron and photon, quark and gluon, etc.). The corresponding mathematics is known but different from "gauge" concept. So absence of Higgs will signify more then just new properties of W-boson at high energies, I think.

I am afraid the excitement may well turn into disappointment with SM when no signs of Higgs are observed. To me Higgs "mechanism" is a highly theoretical (speculative) construction, not phenomenological one (in particle physics at least). I think the right direction is to proceed from non-elementary, permanently coupled things and they are not described with gauge approach.

Should a good physical theory predict phenomena that happen always? Yes, of course. What is a probability of a phenomena that never happens? Zero, of course. Consider then a Rutherford scattering of an electron from a proton in QED. The first Born approximation gives indeed a Rutherford (or Rutherford-like) cross section and the textbooks represent it as a success. At the same time any scattering is experimentally accompanied with photon radiation. The probability of any photon radiation is equal to unity. So QED predicts a phenomenon that never happens - scattering without radiation. Only much later, when treating the infra-red catastrophe, QED books correct this QED failure but not before. I advanced a theory where the radiation is unavoidable: the elastic cross section (i.e., without radiation) is equal to zero, as it should be. Only inclusive cross section is different from zero. In my theory the electron charge and photon degrees of freedom are coupled intrinsically and permanently. They cannot be decoupled unlike QED construction. But my pet theory is in an embryonic state, it cannot be compared to the fourth-order QED calculations of (g-2) yet due to lack of funding.

I used to work with supersymmtries and supergravity in particular when I was a student (1979-80). Supergravity was motivated by canceling infinities in some loops, not by any physical observations. I think nothing has changed since.

Bravo, you repeated Zinn-Justin's words! But whether the supersymmetry is observed physically or it is just another patch of a nice theory?

No, time in physics is not a field. Again, when we speak of fields, we mean forces that change particle positions in time.

By the way, is there any problem with renormalizability because of the scalar massive boson? It is mentioned in http://ipht.cea.fr/Docspht//articles/t98/118/public/publi.pdf

No, on the contrary - outside a body. We cannot check it without a probe body.

Yes, we agree, no doubt. If we speak of E and B, there is no even a notion of gauge invariance, is there? So which physics may be encompassed with the gauge principle? It is a subject of another thread. I just wanted to say here that there are many other ways of constructing theories, apart from gauge (unphysical) principle.

For a force between two bodies to exist, it is not necessary to have a field everywhere. For example, two bodies connected with a spring. Or two not-completely-separated pieces of a chewing gum. They interact because they are pieces (parts) of something complex? They cannot be ever separated, as a matter of fact. Thus there is no problem with the action-at-a-distance (there is no true separation) and there is no field in each point of space. Only where our probe body is.

The Higgs boson was introduced as a patch of an otherwise massless gauge theory, roughly speaking. It is not a God's particle. I will not be surprised if it does not exist. The "gauge principle" is not physical at all either. It does not come alone in QED but with renormalizations. No wonder if such a way of theory "development" fails. I am for a phenomenological way, with a deep physical phenomenology though.