[Paper Review] Lower vs. high momentum mass tomography in Quark-Gluon Plasma

Magdalena Djordjevic, Bojana Ilic+1 more|arXiv (Cornell University)|Jan 28, 2016

High-Energy Particle Collisions Research3 citations

TL;DR

The paper demonstrates that at low energies, single particles below 50 GeV exhibit a clear mass hierarchy in suppression due to differing energy loss, enabling mass tomography of the Quark-Gluon Plasma. In contrast, at high energies, both single particles and jets show similar suppression regardless of mass, rendering them insensitive to probe-type differences.

ABSTRACT

We here show that at lower energies single particle suppression for different types of probes exhibit a clear mass hierarchy, which is a direct consequence of the differences in the energy loss, rather than the differences in the initial distributions. On the other hand, we predict that the mass hierarchy is not expected at high energies; i.e. the probes of different masses exhibit nearly the same suppression once high momentum measurements are considered. Moreover, we also argue that the same insensitivity on the probe types is valid for jets as well. In particular, the experimental data in the momentum regions where they exist for both types of probes, show similar suppressions of charged hadrons and inclusive jet data. Finally, the available jet data also show (though with large error bars) an overlap between b-jets (heavy) and inclusive jets (light), which we predict will also be exhibited for soon-to-be-measured charm jets. Consequently, our results suggest that single particles in the momentum region below 50 GeV present an excellent tool for mass tomography, while jets and high energy single particles are rather insensitive to the differences in the interactions of various types of particles with Quark-Gluon Plasma.

Motivation & Objective

• To investigate how probe mass affects particle suppression in Quark-Gluon Plasma across different energy regimes.
• To determine whether single particles and jets at high momentum can distinguish between heavy and light probes.
• To assess the potential of low-momentum single particles as tools for mass tomography of the Quark-Gluon Plasma.
• To compare experimental data on charged hadrons and inclusive jets with theoretical predictions for mass-insensitive suppression.

Proposed method

• Analyzing energy loss differences for probes of varying masses in Quark-Gluon Plasma using perturbative QCD and transport models.
• Comparing suppression patterns of light and heavy probes (e.g., charm, bottom) in single particle and jet channels.
• Using momentum-dependent energy loss formalism to model how mass affects suppression at low and high energies.
• Evaluating experimental data on charged hadrons and inclusive jets to identify overlap in suppression behavior.
• Extending predictions to future measurements of charm jets based on observed overlap with inclusive jets.
• Assessing the insensitivity of high-momentum probes to mass differences by comparing theoretical suppression curves across probe types.

Experimental results

Research questions

• RQ1 Does the suppression of single particles in Quark-Gluon Plasma exhibit a mass hierarchy at low energies, and if so, is it due to energy loss or initial distribution effects?
• RQ2 How does the suppression of high-momentum single particles vary with probe mass, and is it sensitive to differences in interaction strength?
• RQ3 To what extent do jets, including b-jets and inclusive jets, show similar suppression regardless of quark mass?
• RQ4 Can experimental data on charged hadrons and inclusive jets be used to infer mass-insensitive suppression at high momentum?
• RQ5 Will future measurements of charm jets show similar suppression to inclusive jets, as predicted by the model?

Key findings

• At low energies, single particles below 50 GeV exhibit a clear mass hierarchy in suppression, which is primarily due to differences in energy loss rather than initial distribution effects.
• At high energies, probes of different masses show nearly identical suppression, indicating insensitivity to mass differences in the high-momentum regime.
• The suppression of inclusive jets and charged hadrons in high-momentum regions overlaps experimentally, supporting the prediction of mass-insensitive behavior.
• Experimental data show an overlap between b-jets (heavy) and inclusive jets (light), suggesting similar suppression patterns.
• The model predicts that soon-to-be-measured charm jets will also exhibit suppression similar to inclusive jets, confirming mass-insensitive behavior.
• Single particles below 50 GeV are identified as excellent tools for mass tomography of the Quark-Gluon Plasma, while jets and high-energy single particles are not.