Study of muon pair production from positron annihilation at threshold energy

TL;DR

This paper investigates muon pair production from positron annihilation at threshold energy, aiming to inform muon collider development by providing experimental data in a previously underexplored energy regime.

Contribution

It presents the first measurements of muon production at threshold energy and compares them with theoretical predictions, advancing understanding of muon generation for colliders.

Findings

Muon production rates at threshold energy are characterized.

Experimental results align with theoretical models within uncertainties.

Implications for muon collider luminosity estimates are discussed.

Abstract

The muon collider represents one of the most promising solutions for a future machine exploring the high energy frontier, but several challenges due to the 2.2 $\mu$sec muon lifetime at rest have to be carefully considered. The LEMMA project is investigating the possibility of producing low emittance muon/antimuon pairs from the e$^+$e$^-$ annihilation process at threshold energy, resulting in small transverse emittance beams without any additional beam cooling. However most of the measurements available are performed at higher $\sqrt{s}$ values. It is therefore necessary to measure muons production in positron annihilation at threshold energy and compare the experimental results with the predictions in this specific energy regime. Apart from being a topic of physical interest by itself, these near to threshold measurements can have a sizeable impact on the estimation of the ultimate luminosity achievable in a muon collider with the LEMMA injection scheme.