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Parity Violation: The Biggest Scientific Blunder of the 20th Century?. Dr Mark Hadley. Is Nature Symmetrical?. We thought so until 1956 !!. A Major change in our view of space and time Round Earth Heliocentric view of Universe Special Relativity (time is not absolute)

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## Parity Violation: The Biggest Scientific Blunder of the 20th Century?

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**Parity Violation: The Biggest Scientific Blunder of the 20th**Century? Dr Mark Hadley**Is Nature Symmetrical?**We thought so until 1956 !! • A Major change in our view of space and time • Round Earth • Heliocentric view of Universe • Special Relativity (time is not absolute) • General relativity (spacetime is curved) • Big bang – Universe finite in space and time • Expanding Universe (time asymmetry)**Plan**• Parity violation – the conventional view • My interest • Review of Parity conservation • Mechanics • Electromagnetism • Weak Interactions • An alternative view • Parity is Conserved !!**Space Inversion**Inversion = reflection + 180° rotation Axial or Pseudo vector**Before**After Effect of Parity - momentum The Parity Operator gives the transformation due an inversion of the spatial coordinates**Before**After Effect of Parity - spin**Physical Review October 1956 p254-258**Parity violation in the weak interactions Tsung Dao Lee Chen Ning Yang**Look for an asymmetric outcome**Start with a symmetrical state e- θ 60Ni + e- +υe 60Co I(θ)dθ = k (1 + αcosθ )sinθdθ**Experimentalists**Wu Ambler Hayward Hoppes Hudson National Bureau of Standards USA 1956**actual result**I(θ)dθ = k (1 –v/c cosθ )sinθdθ**Nobel prize winners 1957**Parity violation in the weak interactions Tsung Dao Lee Chen Ning Yang**But not quite so simple…….**Is the initial state symmetrical? “We see from this analysis that the logical path from the observed asymmetry to the inferred nonconservation of parity in β decay is considerably more complex than the popular presentations would indicate.” L. E. Ballentine:**A gravitational explanation for quantum theory**• Aims to explain • QM • Particle spectrum • Fundamental interactions • Predictions • No graviton (Gravity waves are just classical waves) • Spin-half • Parity is conserved**Parity is violated - FACT**The Nobel Prize Committee say so. All the books say so.**Explanations using GR**• Boundary Conditions • Common source **Doh!!**Doh !!**Where have they gone wrong?**• Exactly what has been observed? • Exactly what has been violated? • What, exactly, is the definition of Parity?**Parity in Newtonian Mechanics**Parity conserved Before After F = ma E = ½m v2 F = m(-a) -F = m (-a) -F = (-m)(-a) F = (-m)(-a) (± )E = ½(± m) v2 **Parity in Newtonian Mechanics**P operator is chosen: • For simplicity • To conserve parity • Supported by: Special Relativity: (t-component of the energy momentum 4-vector) General Relativity:**e-**e- e- e- e- Parity in electromagnetism Start with a symmetrical state…… e- Magnetic field pointing out**Parity in Electromagnetism**Parity conserved Before After F = q(E + v x B) Note: -F = q(-E + -v x (-B)) -F = q(-E + -v x B) -F = -q(E + -v x B) -F = -q(E + -v x (-B)) **e-**e- e- e- Parity in electromagnetism e- Magnetic field pointing out**e-**e- e- e- e- Magnetic field pointing in**Duality Transforamtion**• The roles of E and B can be reversed by a duality transformation:**In this order**Parity in Electromagnetism P operator is chosen: • To conserve parity • For simplicity • Supported by the covariant formulation:**Effect of Parity**The Parity Operator gives the transformation due an inversion of the spatial coordinates. We do not have a free choice of P operator. What are the transformations in beta decay?**“We see from this analysis that the logical path from the**observed asymmetry to the inferred nonconservation of parity in β decay is considerably more complex than the popular presentations would indicate.” L. E. Ballentine: The assumption that the Cobalt nucleous is symmetrical is not only non-trivial - it may well be wrong !**e-**e+ Anti 60Co What is the mirror image of a Cobalt atom? 60Co 60Co e- (not to scale)**Parity**• Reverses • Momentum • Lepton number etc. • Charge • Unchanged • Spin • Is conserved**Conclusions**• Space Inversion is a symmetry of Nature • Parity is conserved • The conventional P operator is not conserved.**Just a change of convention?**• The conventional P operator may be combined with another transformation of degenerate multiplets. (eg particle anti-particle, neutrino flavours) • Impacts on unifying theories. “Not merely a matter of convention: on other particles P could have the usual effect.” Weinberg**Parity violation**How could they get it so wrong?**How could they get it so wrong?**• The Parity operation was defined before the experiments were done. • Particles were defined as eigenstates of Parity. • Simplicity of the operator took precendence over conservation - even though QFT required particles and antiparticles to be combined in the same equations. • There was no higher theory to appeal to. Watch this space!**Eigenvectors of P, H,J3 with eigenvalues 0,M,σ**Parity Lorentz Boost**CP violation**• Boundary conditions • Matter dominated Universe • T asymmetry (CPT theorem) • Expanding Universe • Parity = CP for some particles only! • More complicated effects of P on other degeneracies.

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