Pi0 and Eta measurement with photon conversions in ALICE in proton-proton collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports on the measurement of Pi0 and Eta mesons in proton-proton collisions at 7 TeV using photon conversions in ALICE, providing precise spectra down to low transverse momentum and comparing results with theoretical predictions.

Contribution

It introduces a photon conversion method for Pi0 and Eta measurement in ALICE that is independent of electromagnetic calorimeters, enabling low-pt measurements with high resolution.

Findings

Pi0 and Eta spectra measured down to 0.4 and 0.6 GeV/c

Results show good agreement with NLO pQCD calculations

Method achieves high resolution with minimal background

Abstract

We present a measurement of the Pi0 transverse momentum spectrum and of the Eta/Pi0 ratio in proton-proton collisions at sqrt(s) = 7 TeV at the CERN LHC. In this analysis the reconstruction of Pi0 and Eta mesons has been done via photon conversions in the central tracking system of ALICE. Therefore, this method is completely independent from the electromagnetic calorimeters. It makes the Pi0 (Eta) measurement possible down to pt = 0.4 (0.6) GeV/c with a very good resolution and a very small background. For 100 Mio. pp collisions the pt reach is 7 GeV/c. The results are compared to NLO pQCD calculations.