Tabletop Experiments vs Large Accelerators in Hunting New
Tabletop Experiments vs Large Accelerators in Hunting New Physics Alexander Penin Karlsruhe University, Germany DESY, April 2007
Preface
Search for fundamental constituents of Matter Shorter distances Higher energies Larger Accelerators
Discovery of Electron Sir J. J. Thomson (1897)
Measuring Z-boson
Alternative I Probing high energies through quantum effects: Uncertainty Principle Suppression factor High accuracy, low scale experiments, e. g. Muon anomalous magnetic moment Muon decay spectrum (Brookhaven) (TWIST/TRIUMF)
Alternative II New Physics of a different kind, e. g. Mirror Universe Extra Dimensions Very subtle effects Extreme accuracy of theory and experiment
Quantum Electrodynamics (QED)
QED = Quantum Mechanics + Relativity Great success Electron anomalous magnetic moment Nobel Prize 1965 (R. Feynman, J. Schwinger, S. Tomonaga) Fading interest “Landau Pole” Strong and Weak interactions Renaissance Positronium Bhabha scattering
My contribution Phys. Rev. Lett. 85, 1210 (2000) Phys. Rev. Lett. 85, 5094 (2004) Phys. Rev. Lett. 95, 010408 (2005)
Positronium
Discovery of Positron Theory Paul Dirac (1928) Experiment Carl Anderson (1932)
Positronium CV Hydrogen-like bound state of 1934 - First time mentioned 1945 – Baptized (A. E. Ruark) 1951 – Discovered (M. Deutch) and (S. Mohorovicic)
Positronium Main Features Hadronic effects negligible Radius Binding energy Spin Parapositronium Orthopositronium
Positronium Main Features II Hyperfine splitting
Positronium Main Features III Decay rate Lifetime
Timeline of QED Bound States Theory 1920 -1930 s. Quantum mechanics 1930 -1940 s. Early days of quantum field theory, noncovariant perturbation theory. 1949 Feynman‘s covariant perturbation theory. ``. . . there is a moral here for us. The artificial separation of high and low frequencies, which are handled in different ways, must be avoided'' (J. Schwinger) 1986 Beginning of the nonrelativistic effective theory era. (Caswell, Lepage) Now Effective theory + Dimensional regularization
Theory vs Experiment: HFS B. Kniehl, A. P. (2000); R. Hill; K. Melnikov, A. Yelkhovsky (2001) A. P. Mills, Jr. (1983) M. W. Ritter et al. (1984)
Theory vs Experiment: HFS
Theory vs Experiment: Decays “Positronium lifetime puzzle” (1982 -2003)
Theory vs Experiment: Decays B. Kniehl, A. P. ; R. Hill and G. P. Lepage; K. Melnikov, A. Yelkhovsky (2000) Tokyo (Si. O 2 powder, 2003) Michigan (vacuum, 2003)
Theory vs Experiment: Decays Positronium lifetime puzzle is solved !. . . for the moment
Running Positronium Experiments
Halle Zürich München Michigan Tokyo
“Through the Looking-Glass” Lewis Carrol (1871)
Parity Violation in Nature Weak interactions distinguish between left and right! Neutron decay Nobel Prize 1957 (T. D. Lee, C. N. Yang) Standard model Nobel Prize 1979 (S. Glashow, S. Weinberg, A. Salam)
The Mirror Universe: left right Interaction with “normal” particles Gravity (dark matter? ) Mixing A. Salam; I. Kobzarev, L. Okun, Y. Pomeranchuk (1966)
Positronium and the Mirror Universe S. Glashow (1986) Hyperfine splitting Decay rate
The Extra Dimensions Compact extra dimensions T. Kaluza (1921); O. Klein (1926) Invisible at low energies Infinite extra dimensions L. Randall, R. Sundrum (1999) Matter can escape into the extra dimensions! S. Dubovsky, V. Rubakov, P. Tinyakov (2000)
Positronium and the Extra Dimensions Decay rate Gravitational potential
Bhabha Scattering
H. J. Bhabha (1935)
Luminosity of Colliders Bhabha scattering is the “standard candle” Easy to measure QED dominated
Luminosity of Colliders High energy colliders: LEP, ILC Low energy colliders: BABAR/PEP-II, BELLE/KEKB, BES/BEPC, KLOE/DAPHNE, VEPP-2 M, . . .
Luminosity of KLOE, CMD Giga. Z/ILC Colliders
Radiative Corrections H. J. Bhabha (1935) R. Bonciani et al. ; A. P. (2005)
Summary In the ultimate era of giant accelerators we should not forget the tabletop experiments After a rise and a fall, QED stocks are traded high again
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