Applicability of transverse mass scaling in hadronic collisions at the LHC

TL;DR

This study assesses the effectiveness of transverse mass scaling in describing particle spectra in proton-proton collisions at 7 TeV, finding it limited at low transverse momentum and dependent on the choice of reference particles.

Contribution

It provides a detailed evaluation of transverse mass scaling applicability in LHC proton-proton collision data, highlighting its limitations and conditions for better performance.

Findings

Transverse mass scaling fails to accurately describe spectra at low pT.

Using kaons as reference particles improves scaling performance.

Scaling behavior is observed at high pT for most particles except possibly charged kaons.

Abstract

We present a study on the applicability of transverse mass scaling for identified particle spectra in proton-proton collisions at $\sqrt{s}=7$ TeV based on data taken by the ALICE experiment at the LHC. The measured yields are parametrized and compared to estimates obtained from a generalized transverse mass scaling approach applied to different reference particle spectra. It is found that generalized transverse mass scaling is not able to describe the measured spectra over the full range in transverse momentum. At low $p_{\rm T}$, deviations of $20$% or more are obtained, in particular if pions are used as reference particles. A better scaling performance is obtained, when kaons are used as reference particles. At high $p_{\rm T}$ all tested spectra with the possible exception of the charged kaons exhibit a scaling behavior. Investigating the feed-down contributions from resonance decays to the charged pion yields reveals, that using them as reference a general scaling may not be achievable. Our findings imply that for precision measurements of direct photon and di-electron spectra at low transverse momentum one should measure the relevant hadronic background, instead of relying on $m_{\rm T}$ scaling for its estimate.