Sunday 11 May 2008

Pauli's Other Exclusion Principle

As I am currently stretched between continents, I ponder over the differences between the US and Europe. Apart from the taste of food and the size of humans, there seems to be a fundamental difference at the level of particle physics. Let's have a closer look at the time and place of discoveries of elementary particles:
  • Tau neutrino, 2000, Fermilab, United States
  • Top quark, 1995, Fermilab, United States
  • W and Z bosons, 1983, CERN, Switzerland
  • Gluon, 1979, DESY, Germany
  • Bottom quark, 1977, Fermilab, United States
  • Tau, 1975, SLAC, United States
  • Charm quark, 1974, SLAC/Brookhaven, United States
  • Up, down, and strange quarks, 1968, SLAC, United States
  • Muon neutrino, 1962, Brookhaven, United States
  • Electron neutrino, 1956, Los Alamos, United States
  • Muon, 1936, Caltech, United States
  • Photon, 1905, Patent Office in Bern, Switzerland
  • Electron...let's skip that one for simplicity...
This can be summarized as Pauli's other exclusion principle:

Fermions are discovered in the US, whereas bosons are discovered in Europe.
Pauli's other exclusion principle has been confirmed in numerous experiments, sometimes un a quite spectacular way. Around 1974, the most powerful accelerator in the world was the ISR at CERN who produced charmonium in commercial quantities. However, since a discovery of the J/Psi particle at CERN would contradict Pauli's other exclusion principle, the experiment set its cuts so as to reject events with pT < 3.2 GeV (the mass of the J/Psi particle is 3.1 GeV). Later on, some significant efforts were invested to miss the Upsilon particle. The cancellation of the SSC can also be explained by Pauli's other exclusion principle: the SSC would be able to discover the Higgs boson.

Since, there is no more doubt that Pauli's other exclusion principle is a fundamental law of nature, it can be used to formulate predictions. One obvious implication is that Higgs searches at the Tevatron are pointless, and resources should be reallocated to searches for new heavy quarks. The Higgs boson, if it exists, will be discovered at the LHC. The new physics at the LHC, however, is severely constrained. Typical solutions to the hierarchy problem predict new fermions at the TeV scale. The little Higgs or extra dimensional scenarios predict a vector-like partner of the top quark at accessible energies, while supersymmetry predicts fermionic partners of the gauge bosons. On the other hand, the Standard Model with a light Higgs is perfectly consistent with Pauli's other exclusion principle...

Thanks to Jose Ramon for pointing out the facts to me.


Luboš Motl said...

Thanks for your theoretical discovery! More discussions here. The only obvious problems are electrons and neutrons. ;-) But muon and photon work out well.

Jester said...

Great Britain, at the fundamental level, doesnt count as Europe. It's not as surprising, is it?

Anonymous said...

Nice observation!

I don't think there is any problem with Pauli's other principle with the electron since it was discovered (1897) before Pauli was born (1900). Neutrons and protons are not serious problems either since they are not elementary particles any way. :-)

Anonymous said...

Hey jester, sleeping on the job again ? I am sure you would have tons of things to report, if you just weren't that lazy!


Vivek said...

nice summary. A minor quibble with something you wrote,

"...the experiment rejected the data with pT < 3.2 GeV (the J/Psi is at 3.1 GeV)..."

You mean they rejected events with mass < 3.2 and not pT. The mass of the J/Psi is 3.1 GeV; it doesn't have a fixed pT.

Anonymous said...

None of the particles discussed are scalars. Pauli's other principle so far has only been tested on vector bosons. So we cannot use it to predict where the Higgs might be discovered. Maybe in China? Or Russia?