A physicist's confidence in CPT symmetry is founded on excellent experimental grounds. Let us look at protons and antiprotons. The proton to electron mass ratio is measured to be
$m_{p^{+}} / m_{e} = 1836.1526724718(80)$
compared to the antiproton to electron mass ratio
$m_{p^{-}} / m_{e} = 1836.152674(5)$
measured by Hori et al in 2006. Gabrielse also discusses extremely accurate tests of mass equivalence. The positron and electron masses are measured at
$m_{e^{+}} = 0.510998910(13)$ MeV$/c^{2}$
$m_{e^{-}} = 0.510998910(13)$ MeV$/c^{2}$
However, these charged particles are unlike neutrinos in a number of ways. For instance, the charged lepton mixing matrix is usually the identity, since weak states and mass states coincide. People have also studied the tight bounds on things like proton positron oscillations.
14 years ago
Unviolation??? Not symmetry?
ReplyDeleteThe proton mass mp is composed primarily of gluons, and not of the quarks (the up quark and down quark) making up the proton. Hence mp, and therefore the ratio μ, are easily measurable consequences of the strong force. In fact, in the chiral limit, mp is proportional to the QCD energy scale, ΛQCD.
The neutrons are important for the atoms stability (gluons?) but as free it is not stable.
How would an asymmetry in up-and down quarks work?
http://www.azonano.com/news.asp?newsID=5851
http://arxiv.org/abs/1002.1048
http://p25ext.lanl.gov/e866/e866.html
http://p25ext.lanl.gov/e866/papers/e866lanl98/nusea_v4.pdf
ReplyDeleteThe results of these studies have shown that a proton is composed of three valence (core) quarks—two up quarks and a down quark (uud)—held together by gluons in a Sea of quark-antiquark pairs, (coming from gluon-splitting or virtual pions?).
the scientific community had assumed that there were equal numbers of u- (anti-up) and d- quarks in this “nucleonic sea,” a condition known as flavor symmetry. 1991 - evidence for a considerable excess of d- relative to u- in the nucleonic sea.
depending on the “momentum fraction,” the fraction of a proton’s momentum that the sea antiquarks carry.
over the range of momentum fractions
implies that in different momentumfraction
regions, asymmetric processes (such as virtual-pion production) dominate to different extents over symmetric processes (such as gluon splitting),
The mass of hadrons is essentially from the field not the quarks themselves, which in any scheme have tiny masses compared to the whole hadron.
ReplyDeleteTherefore, if you are interested in measurable quantities (real world observables) you are interested in hadron masses, not (directly unobservable) quark masses. You can't isolate a quark even in principle, so Mach would say the mass of a quark isn't physics. You can only directly measure the hadron masses.
Thus, the masses of particles are their alleged "antiparticles" are similar simply because the field structures are similar.
If you really want to understand masses, you need to understand the field structure in detail. This means facing the facts of vacuum polarization, the gain of energy by virtual fermions as they are physically pulled apart (polarized) by an electric field from the particle which attracts the unlike charged virtual fermion and repels the like charged virtual fermion. This delivers energy from the electric field to the virtual fermions, which thus are not quite so virtual anymore! The pulling apart (polarization) affects the survival time and thus physically undermines the uncertainty principle, shifting them from being totally off-shell to closer to being on the mass shell. Thus, the "virtual" fermions in a strong electromagnetic field (high electric polarization) may become more real and are affected by the exclusion principle, which quantizes their positions. This imposes a geometric shell structure configuration on the field by analogy to atomic or nuclear shell structure, determining the hadron masses.
And how can this geometrization be done if the field is infinite?
ReplyDeleteThe pair production field isn't infinite: there are UV and IR cutoffs on the energies and thus distances around a charge where polarizable pair production of virtual fermions occurs. No infinities are present. There can't be an infinite number of polarized virtual fermions because the mechanism which produces them depends on energy taken from the electromagnetic field, which isn't infinite.
ReplyDelete“It always bothers me that, according to the laws as we understand them today, it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space [because there is an infinite series of terms in the perturbative expansion to Feynman's path integral] ... Why should it take an infinite amount of logic to figure out what one tiny piece of spacetime is going to do? So I have often made the hypothesis that ultimately physics will not require a mathematical statement, that in the end the machinery will be revealed, and the laws will turn out to be simple, like the chequer board with all its apparent complexities.”
– Richard P. Feynman, The Character of Physical Law, November 1964 Cornell Lectures, broadcast and published in 1965 by BBC, pp. 57-8.
Funny that people STILL don't grasp this 45 years later. ;-)
Ad hoc?
ReplyDelete"So I have often made the hypothesis that ultimately physics will not require a mathematical statement,"
the SUSY problem?
There should be a more simle solution?
Ah ... yet another arrogant person who thinks they can tell me how to understand mass using QFT. I've been hearing this bullshit for 30 years. QFT does not describe mass.
ReplyDeleteKeep it short, Nigel, or it gets deleted.
" QFT does not describe mass. "
ReplyDeleteIt has be used to accurately predict the masses of quarks, leptons and quark combinations in hadrons. True, arXiv censors it. So who's arrogant now? Just suppose you are wrong about this, at what point do you stop burning bridges and making stupid statements about the definition of arrogance, instead of keeping to the facts? Do you think that politeness in science means not insisting on facts, and that insisting on facts is arrogance?
When an accurate spectrum of previously unobserved masses is computed (say, for the LHC).
ReplyDeleteQCD does not of course predict the masses of quarks and leptons. They are inputs coded by the couplings to Higgs assumed to be proportional to the masses! What has been done in lattice QCD are estimates for say rho meson mass and involving a lot of inputs.
ReplyDeleteA comment about the actual topic. The different mass scales for neutrinos and antineutrinos need not correspond to genuine CPT breaking in TGD framework. Both neutrinos and antineutrinos have same mass spectrum characterized by p-adic mass scales and in the experimental situation the mass scales would be selected differently.
The wikipedia reference to the positron mass is wrong, unless you assume CPT. See the PDG for the data on the difference between the positron and electron masses.
ReplyDeleteOK, so here is a handy PDG link, stating that for electrons and positrons
ReplyDelete$\Delta m / m_{av} < 8 \times 10^{9}$
Sorry, as I understand it the color is the problem, not the flavour as much, in spite of the fourth gen. possibility.
ReplyDeleteNeutron as an oscillation? That gives a resonance strong - weak force? An oscillation has no definitive value.
But the infinity comes in-between as collapsing clay-bridges gives quicksand :) That's why the infinity gives supraconduction etc. It is a collapsing (=computation) matrix?
Sorry for the analogy.
The absolute measurement of the mass of the electron is 0.013 eV while the difference between electron and positron is slightly smaller at 0.004eV.
ReplyDeleteHowever, if instead you ask for the mass of the electron in atomic mass units, its accuracy is known to a higher degree; 23 parts in 54857990943, which is equivalent to 0.0002 eV.
So one could hope for a more accurate measurement of the positron in amu, or a relative measurement of the mass difference that is a little more accurate.
The neutrino masses are something like 0.05, 0.009, and 0.0004 eV, so it appears that the data for the positron is close enough to the electron to indicate a difference smaller than the neutrino mass differences.