Mirror Quantum Tomography Finds Unexpected Polarization Phenomena in Z Boson Production in pp Collisions at the LHC

TL;DR

This paper reveals unexpected polarization phenomena in Z boson production at the LHC, identified through quantum tomography, with the ATLAS data showing vortex-like spin configurations and entropy maxima.

Contribution

It introduces a model-independent quantum tomography approach to analyze Z boson polarization, uncovering novel vortex-like spin structures in experimental data.

Findings

ATLAS data shows vortex-like Z boson spin configurations.

Local maximum of polarization entropy observed.

Broad consistency across CMS and LHCb data.

Abstract

The ATLAS, CMS and LHCb collaborations have reported data for the inclusive production of lepton pairs with invariant mass 80-100 GeV in pp collisions. We find the ATLAS data from at $\sqrt{s}$ =8 TeV shows an unexpected vortex-like configuration of Z boson spins circulating around the beam axis. Associated with this structure is a local maximum of the entropy of the Z-boson polarization density matrix extracted using quantum tomography. Data from CMS and LHCb at $\sqrt{s}=13$ TeV are broadly consistent. The origin of the observed phenomena is unknown but generally related to observables that are formally odd under charge conjugation, parity and time-reversal. Quantum tomography using Standard Model lepton couplings to the Z boson determines the spin-1 density matrix of the system model-independently, bypassing any model of the hadronic production process.