Electric force and photons

[Severian]

This is only one interpretation of Feynman diagrams and calculations. The interpretation is Dirac's. Feynman never really agreed to it' date=' since he himself invented our most useful approach: Path Integrals over all routes. Feynman would have been the first to jettison 'anti-particles' in favour of a new interpretation that would explain attraction.

We should be at least half as creative![/quote']

 

It is the Feynman-Stuckleberg interpretation, and has nothing to do with Dirac. In fact, Dirac tried to explain the same ideas using the 'Dirac Sea' (which didn't really work). The Feynman-Stuckleberg Interpretation was advocated by Feynman (which is why it has his name) and it is a cornerstone of his Path integral formulation of QFT. In fact, QFT came into existence as a desire to explain the FS interpretation rigourously! Normal QM cannot explain the creation of particle-antiparticle pairs, and it was the need to explain antiparticles (from the FS interpretation) which made QFT necessary.

[Severian]

(a) There isn't enough hard evidence to force us to accept this calculation.

 

CP-violation (and thus T violation) is extrememly well studied now. The evidence for it is overwhelming.

 

(b) The Standard Model is conceded to be flawed and incomplete anyway.

 

Would you care to explain your reasoning? The Standard Model is the best tested theory in science ever! There has never been an experimental test of the Standard Model which has failed. In fact, one of the major problems in particle physics today is that the Standard Model is too good, that it leaves very little room to find more aesthetically pleasing (or more predictive) models!

[MetaFrizzics]

Just let me get out my complimentary textbook on CP violation:

 

CP Violation by I.I. Bigi & A.I. Sanda. Cambridge UP 2000.

 

I'll never sound more eloquent on this subject than my friend Mr. Bigi.

 

The dynamical ingredients for numerous and multi-layered manifestations of CP and T violations do exist or are likely to exist. Accordingly, we search for them in many phenomenae...

 

Cathedral Builder's paradigm

The analogy of the cathedral goes deeper...At first sight a cathedral looks like a very complicated and confusing structure (but) one that has a multi-faceted and multi-layered - with a coherent theme! We cannot remove any of its elements without diluting its architectural soundness and intellectual message. Neither can we in our efforts to come to grips with CP violation....

 

Present Status:

We know unequivocally that CP symmetry is not exact in nature...

 

The presence of direct CP violation has been observed...

 

If the KM mechanism is a significant actor ...then there must be large CP asymmetries in the deays of beauty hadrons

 

Some of these asymmetries are predicted with high parametric reliability.

 

New theoretical technologies will allow us to translate such parametric reliability into quantitative accuracy.

 

Any significant difference between predictions for the asymmetries reveals the intervention of NEW PHYSICS.

 

We find it likely that deviations from the KM predictions will show up here.

 

There is intriguing indirect evidence for the presence of NEW PHYSICS coming from the patterns in the quark mass matrices, baryogenesis in the universe and neutrino physics.

 

There are many models of CP violation based upon NEW PHYSICS eagerly awaiting their turn in the wings.

 

Agenda for the Future

 

...B decays constitute an almost ideal, certainly optimal and unique lab, due to dynamic interplay of all three quark families....the better the shape of the KM triangle is known, the more sensitive we become to the intervention of NEW PHYSICS....a ~10% accuracy seems achievable...

 

It is our firm expectation that a comprehensive analysis of the weak decays of beauty hadrons will reveal the presence of NEW PHYSICS...

 

Personally we believe that, even if no deviation from the KM predictions were uncovered, we would find that the CKM parameters, in particular the angle s of the KM triangle, carry special values that would give us clues about NEW PHYSICS.

 

A vigorous research program must be continued for light fermion systems, ...specifically in the decays of kaons and hyperons and in electric dipole moments...

 

A comprehensive analysis of charm decays with special emphasis on D^o D^-o oscillations and CP violation is a moral imperative!...

 

There is still unfinished business in our analysis of weak decays of strange hadrons..

 

the quest for EDMs has to be continued...

 

A determined effort must be mounted for CP properties of t leptons, charm hadrons, and top quarks.

 

A comprehensive detailed analysis of beauty decays is bound to provide us with essential information on fundamental dynamics.

 

No direct observation of new fields - like SUSY partners - can supersede that information.

 

It is the Feynman-Stuckleberg interpretation, and has nothing to do with Dirac.

I like to credit Dirac with antiparticles, even though he was formally too timid to claim it for himself.

[Severian]

Just let me get out my complimentary textbook on CP violation:

 

Sometimes I don't know what to do with you....

 

From the article you quote (in an attempt to claim CP violation is not on firm footing):

 

We know unequivocally that CP symmetry is not exact in nature...

 

The presence of direct CP violation has been observed...

 

So you prove my case for me.

 

The references to 'new physics' in the article' date=' is not new physics in the way you suppose. They suggest extensions to the Standard Model, not replacements. These are things like supersymmetry.

 

Personally I think the evidence for new physics from CP violation is rather weak (apart from maybe the baryon asymmetry problem). That is not to say that it is not a good place to look - it is, but even the circumstantial evidence is rather lacking.

 

 

I like to credit Dirac with antiparticles, even though he was formally too timid to claim it for himself.

 

Dirac's anti-particles - the 'holes' in the Dirac sea - are rather different to the picture of antiparticles that we now have.

[MetaFrizzics]

So you prove my case for me.

 

The references to 'new physics' in the article, is not new physics in the way you suppose. They suggest extensions to the Standard Model, not replacements. These are things like supersymmetry.

I thought you'd be pleased.

 

But I think 'new physics' is a matter of degree... and dependant upon what is actually found in the end. I am not of course advocating we throw away the Standard Model...yet.

Dirac's anti-particles - the 'holes' in the Dirac sea - are rather different to the picture of antiparticles that we now have.

...and rather different to the picture we will have ...shortly.

[J.C.MacSwell]

A particle travelling backwards in time is an anti-particle[/b']. This has nothing to do with attractive forces.

 

Isn't it equivalent to an anti-particle moving forward in time?

[Severian]

Isn't it equivalent to an anti-particle moving forward in time?

 

Yes, that is what I meant.

 

A particle state flowing backwards in time: [math] \psi = u_{(s)}(\vec{p}) e^{-i(E(-t)-\vec{p} \cdot \vec{x})}[/math] is the same as an antiparticle flowing forward in time [math]\psi = v_{(-s)}(-\vec{p}) e^{i(Et-\vec{p} \cdot \vec{x})}[/math] as long as we define [math]v_{(-s)}(-\vec{p})=u_{(s)}(\vec{p})[/math].

[MetaFrizzics]

I think there is a subtle but real conceptual and physical difference between viewing a particle moving backward in time, and viewing the same particle as an anti-particle moving forward in time.

 

Secondly, it should be obvious from the plain example of running a film backwards in time that one can account for attractive forces this way in a simple and straightforward manner. However this is not the same as the current model for anti-particle behaviour. This means that if we want to model attractive force, we have to have a selective and simple framework that can distinguish a time arrow for particle attraction from an arrow for particle repulsion.

[Severian]

I think there is a subtle but real conceptual and physical difference between viewing a particle moving backward in time' date=' and viewing the same particle as an anti-particle moving forward in time.

 

Secondly, it should be obvious from the plain example of running a film backwards in time that one can account for attractive forces this way in a simple and straightforward manner. However this is [b']not[/b] the same as the current model for anti-particle behaviour.

 

It is exactly the same thing. Our mathematical description of a particle travelling backwards in time is identical to our mathematical description of an anti-particle travelling forward in time, as you can see from my previous post. This is inherent to Quantum Field Theory, which is most certainly part of our 'current model'.

[MetaFrizzics]

It is exactly[/b'] the same thing. Our mathematical description of a particle travelling backwards in time is identical to our mathematical description of an anti-particle travelling forward in time, as you can see from my previous post. This is inherent to Quantum Field Theory, which is most certainly part of our 'current model'.

This is all agreed. My point was only that by putting aside these versions of 'time reversal' and embracing a much simpler approach, namely the kind of 'time reversal' observed by running a film backward, one can account for attractive forces in an apparently straightforward manner. And an approach could be formulated that allowed for selective superimposition of both backward and forward motion as respective explanations of attractive and repulsive forces.