Hadron Mass Spectrum from Lattice QCD

TL;DR

This paper uses lattice QCD simulations to reveal a large, previously unconfirmed spectrum of hadron states that grow exponentially and influence thermodynamic properties below the critical temperature.

Contribution

It demonstrates the existence of numerous hadron states beyond experimental knowledge through lattice QCD and models their impact on QCD thermodynamics.

Findings

Evidence for many additional hadron states beyond known spectrum.

Hadron mass spectrum grows exponentially up to 155 MeV.

Estimates of spectral weight for undetected states.

Abstract

Finite temperature lattice simulations of quantum chromodynamics (QCD) are sensitive to the hadronic mass spectrum for temperatures below the "critical" temperature T_c ~ 160 MeV. We show that a recent precision determination of the QCD trace anomaly shows evidence for the existence of a large number of hadron states beyond those known from experiment. The lattice results are well represented by an exponentially growing hadron mass spectrum up to a temperature T = 155 MeV. Using simple parametrizations we show how one may estimate the total spectral weight in these yet undermined states.