Measurement of the Z-Boson Mass

Area of Science:

• Particle Physics
• High-Energy Physics
• Collider Physics

Background:

• The Z-boson is a fundamental particle mediating the weak nuclear force.
• Precise measurements of the Z-boson mass are crucial for testing the Standard Model of particle physics.
• Previous Z-boson mass measurements have been performed at various colliders.

Purpose of the Study:

• To report the first dedicated measurement of the Z-boson mass at the Large Hadron Collider (LHC).
• To utilize Z→μ⁺μ⁻ decays for a precise Z-boson mass determination.
• To compare the measurement with existing data and theoretical predictions.

Main Methods:

• Analysis of proton-proton collision data at a center-of-mass energy of 13 TeV.
• Utilizing data collected by the LHCb experiment in 2016 with an integrated luminosity of 1.7 fb⁻¹.
• Employing a template fit to the dimuon (μ⁺μ⁻) mass distribution.

Main Results:

• The Z-boson mass was measured to be 91,185.7 ± 8.3 (statistical) ± 3.9 (systematic) MeV.
• This represents the first dedicated Z-boson mass measurement at the LHC.
• The result shows consistency with previous measurements and global electroweak fits.

Conclusions:

• The measurement provides a new benchmark for Z-boson mass determination at a hadron collider.
• The consistency of the result reinforces the validity of the Standard Model.
• This measurement contributes to the ongoing effort of precision physics at the LHC.