Synopsis: How to Untangle Quark and Gluon Jets

Inspired by a text-mining technique, scientists have developed a more direct way to distinguish quark jets from gluon jets in high-energy particle collisions.
Synopsis figure
E. Metodiev and J. Thaler/MIT

High-energy particle collisions spew forth a mash of different particles, often in the form of collimated streams, or “jets.” Jets are comprised of hadrons (such as protons, neutrons, mesons), but they originate from accelerated quarks and gluons. Eric Metodiev and Jesse Thaler of the Massachusetts Institute of Technology, Cambridge, have now adapted a text-mining technique in order to determine the properties of such quark- and gluon-initiated jets directly from data. Compared with indirect approaches that involve simulations to understand data, their method may lead to more accurate determinations of jet properties, which provide important clues about the behavior of quarks and gluons at high energies.

The researchers rely on a technique called topic modeling, which was originally developed to identify themes in written documents. Say you wanted to analyze how often the subject of dogs appears in a document but not pets in general. Topic modeling would allow you to identify words unique to this topic (e.g., bark, canine) and to then use these identifiers to pinpoint how often and where the topic shows up.

Metodiev and Thaler demonstrated that the same methodology can be applied to jets. The duo compared data from quark-enriched and gluon-enriched samples of jets and showed that it’s possible to eliminate overlapping properties of the two jet types and identify those distinct to each one. These distinct properties include the number of particles in the jet and the jet’s mass, and they can be used to determine the distribution and fraction of each jet type within a sample. The approach could also be applied to high-energy jets initiated by particles other than quarks and gluons.

This research is published in Physical Review Letters.

–Michelle Hampson

Michelle Hampson is a freelance science writer based in Toronto.


Features

More Features »

Announcements

More Announcements »

Subject Areas

Particles and Fields

Previous Synopsis

Next Synopsis

Related Articles

Synopsis: How Dark Matter Shaped the First Galaxies
Astrophysics

Synopsis: How Dark Matter Shaped the First Galaxies

Simulations show that competing models of dark matter produce primordial star-forming regions that look very different from one another. Read More »

Synopsis: A New Plasma-Based Axion Detector
Particles and Fields

Synopsis: A New Plasma-Based Axion Detector

A proposed device could detect the hypothesized dark matter particle in a mass regime not probed by other devices. Read More »

Focus: “Quantum Foam” Scrubs Away Gigantic Cosmic Energy
Particles and Fields

Focus: “Quantum Foam” Scrubs Away Gigantic Cosmic Energy

Theory suggests that empty space is filled with enormous energy, but according to a new proposal, this energy may be hidden because its effects cancel at the tiniest scales. Read More »

More Articles