Search for Extra Dimensions in Boson and Fermion Pair Production in e+e- Interactions at LEP

TL;DR

This paper searches for signs of extra spatial dimensions through deviations in boson and fermion pair production, as well as graviton-Z boson associated production, using LEP data, but finds no significant evidence and sets lower bounds on the new gravity scale.

Contribution

It provides the first experimental constraints on extra dimensions affecting pair production processes at LEP energies.

Findings

No significant deviations observed in pair production rates.

Lower limits over 1 TeV set on the scale of extra dimensions.

Constraints improve previous bounds on theories with extra spatial dimensions.

Abstract

Extra spatial dimensions are proposed by recent theories that postulate the scale of gravity to be of the same order as the electroweak scale. A sizeable interaction between gravitons and Standard Model particles is then predicted. Effects of these new interactions in boson and fermion pair production are searched for in the data sample collected at centre-of-mass energies above the Z pole by the L3 detector at LEP. In addition, the direct production of a graviton associated with a Z boson is investigated. No statistically significant hints for the existence of these effects are found and lower limits in excess of 1 TeV are derived on the scale of this new theory of gravity.