Precision direct photon spectra at high energy and comparison to the 8 TeV ATLAS data

TL;DR

This paper presents a highly precise calculation of direct photon spectra at high energies, incorporating advanced resummation techniques and electroweak effects, and compares these predictions to 8 TeV ATLAS data, highlighting the importance of these effects.

Contribution

The work introduces a comprehensive prediction of direct photon spectra including threshold resummation and electroweak effects, matched to fixed order calculations, and demonstrates improved data agreement.

Findings

Enhanced agreement with ATLAS data when including all effects.

Threshold resummation and electroweak Sudakov effects are crucial.

Numerical predictions provided for experimental comparison.

Abstract

The direct photon spectrum is computed to the highest currently available precision and compared to ATLAS data from 8 TeV collisions at the LHC. The prediction includes threshold resummation at next-to-next-to-next-to-leading logarithmic order through the program PeTeR, matched to next-to-leading fixed order with fragmentation effects using JetPhox and includes the resummation of leading-logarithmic electroweak Sudakov effects. Remarkably, improved agreement with data can be seen when each component of the calculation is added successively. This comparison demonstrates the importance of both threshold logs and electroweak Sudakov effects. Numerical values for the predictions are included.