Tabletop Experiments vs Large Accelerators

Alexander Penin

Karlsruhe University, Germany

DESY, April 2007

in Hunting New Physics

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

Uncertainty Principle

High accuracy, low scale experiments, e.g.

Muon anomalous magnetic momentMuon decay spectrum

(Brookhaven)

(TWIST/TRIUMF)

Probing high energies through quantum effects:

Suppression factor

Alternative II

Very subtle effects

Mirror Universe

Extra Dimensions

New Physics of a different kind, e.g.

Extreme accuracy of theory and experiment

Quantum Electrodynamics (QED)

QED = Quantum Mechanics + Relativity

Nobel Prize 1965 (R.Feynman, J.Schwinger, S.Tomonaga)

Great success

Electron anomalous magnetic moment

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 Experiment

Paul Dirac (1928)

Carl Anderson (1932)

Positronium CV

1934 - First time mentioned (S.Mohorovicic)

1945 – Baptized (A.E.Ruark)

1951 – Discovered (M.Deutch)

Hydrogen-like bound state of and

Binding energy

Radius

Positronium Main Features

Hadronic effects negligible

Spin ParapositroniumOrthopositronium

Positronium Main Features II

Hyperfine splitting

Positronium Main Features III

Decay rate

Lifetime

Quantum mechanics

Early days of quantum field theory, noncovariant perturbation theory.

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''

Beginning of the nonrelativistic effective theory era. (Caswell, Lepage)

Effective theory + Dimensional regularization

1930-1940s.

1949

(J. Schwinger)

1986

Now

1920-1930s.

Timeline of QED Bound States Theory

Theory vs Experiment: HFS

M.W.Ritter et al. (1984)

A.P.Mills, Jr. (1983)

B.Kniehl, A.P. (2000); R.Hill; K.Melnikov, A.Yelkhovsky (2001)

Theory vs Experiment: HFS

Theory vs Experiment: Decays

“Positronium lifetime puzzle” (1982-2003)

Theory vs Experiment: Decays

Tokyo (SiO2 powder, 2003)

Michigan (vacuum, 2003)

B.Kniehl, A.P.; R.Hill and G.P.Lepage; K.Melnikov, A.Yelkhovsky (2000)

Theory vs Experiment: Decays

Positronium lifetime puzzle is solved !

. . . for the moment

Running Positronium Experiments

Zürich

Michigan

Tokyo

Halle

München

Lewis Carrol (1871)

“Through the

Looking-Glass”

Weak interactions distinguish between left and right!

Nobel Prize 1957 (T.D.Lee, C.N.Yang)

Parity Violation in Nature

Neutron decay

Standard model

Nobel Prize 1979 (S.Glashow, S.Weinberg, A.Salam)

The Mirror Universe

A.Salam; I.Kobzarev, L.Okun, Y.Pomeranchuk (1966)

Interaction with “normal” particles

Gravity (dark matter?)

Mixing

Mirror Universe: left right

Positronium and the Mirror Universe

S.Glashow (1986)

Hyperfine splitting

Decay rate

The Extra Dimensions

L.Randall, R.Sundrum (1999)

S.Dubovsky, V.Rubakov, P.Tinyakov (2000)

T.Kaluza (1921); O.Klein (1926)

Compact extra dimensions

Infinite extra dimensions

Matter can escape into the extra dimensions!

Invisible at low energies

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 measureQED dominated

BABAR/PEP-II, BELLE/KEKB, BES/BEPC,

High energy colliders:

LEP, ILC

Low energy colliders: KLOE/DAPHNE, VEPP-2M, . . .

Luminosity of Colliders

Luminosity of Colliders

GigaZ/ILC

KLOE, CMD

H.J.Bhabha (1935)

R.Bonciani et al.; A.P. (2005)

Radiative Corrections

Summary

In the ultimate era of giant accelerators we should not forget the tabletop experimentsAfter a rise and a fall, QED stocks are traded high again