Darkish Matter Detective Work: A Revolutionary Strategy on the Giant Hadron Collider

Researchers examine whether or not darkish matter particles really are produced inside a jet of ordinary mannequin particles.

The existence of darkish matter is a long-standing puzzle in our universe. Darkish matter makes up a couple of quarter of our universe, but it doesn’t work together considerably with atypical matter. The existence of darkish matter has been confirmed by a sequence of astrophysical and cosmological observations, together with within the beautiful latest photos from the James Webb Area Telescope. Nonetheless, updated, no experimental remark of darkish matter has been reported. The existence of darkish matter has been a query that prime vitality and astrophysicists all over the world have been investigating for many years.

Developments in Darkish Matter Analysis

“That is the explanation we do analysis in fundamental science, probing the deepest mysteries of the universe. The Giant Hadron Collider at CERN is the biggest experiment ever constructed, and particle collisions creating big-bang-like situations will be exploited to search for hints of darkish matter,” says Professor Deepak Kar, from the College of Physics on the College of the Witwatersrand in Johannesburg, South Africa.

A graphic illustration of how semi-visible jets will seem within the ATLAS detector, ought to they exist. Credit score: CERN

Working on the ATLAS experiment at CERN, Kar and his former PhD pupil, Sukanya Sinha (now a postdoctoral researcher on the College of Manchester), have pioneered a brand new method of trying to find darkish matter. Their analysis has been revealed within the journal, Physics Letters B.

A New Strategy to Unraveling Darkish Matter

“There have been a plethora of collider searches for darkish matter over the previous few a long time to date have targeted on weakly interacting huge particles, termed WIMPs,” says Kar. “WIMPS is one class of particles which might be hypothesized to clarify darkish matter as they don’t take in or emit mild and don’t work together strongly with different particles. Nonetheless, as no proof of WIMPS’ has been discovered to date, we realized that the seek for darkish matter wanted a paradigm shift.”

Dr. Sukanya Sinha and Professor Deepak Kar. Credit score: Wits College

“What we have been questioning, was whether or not darkish matter particles really are produced inside a jet of ordinary mannequin particles,” stated Kar. This led to the exploration of a brand new detector signature often known as semi-visible jets, which scientists by no means checked out earlier than.

Excessive vitality collisions of protons usually consequence within the manufacturing of a collimated spray of particles, collected in what’s termed as jets, from the decay of atypical quarks or gluons. Semi-visible jets would come up when hypothetical darkish quarks decay partially to Customary-Mannequin quarks (identified particles) and partially to secure darkish hadrons (the “invisible fraction”). Since they’re produced in pairs, usually together with further Customary-Mannequin jets, the imbalance of vitality or the lacking vitality within the detector arises when all of the jets should not absolutely balanced. The path of the lacking vitality is usually aligned with one of many semi-visible jets.

This makes searches for semi-visible jets very difficult, as this occasion signature can even come up on account of mis-measured jets within the detector. Kar and Sinha’s new method of on the lookout for darkish matter opens up new instructions in on the lookout for the existence of darkish matter.

“Despite the fact that my PhD thesis doesn’t comprise a discovery of darkish matter, it units the primary and moderately stringent higher bounds on this manufacturing mode, and already inspiring additional research,” says Sinha.

The ATLAS Collaboration at CERN has highlighted this as one of many flagship outcomes to come back out at summer time conferences.

Reference: “Seek for non-resonant manufacturing of semi-visible jets utilizing Run 2 information in ATLAS” by The ATLAS Collaboration, 11 November 2023, Physics Letters B.
DOI: 10.1016/j.physletb.2023.138324

Experiments on the Giant Hadron Collider in Europe, just like the ATLAS calorimeter seen right here, are offering extra correct measurements of basic particles. Credit score: Maximilien Brice, CERN

The ATLAS experiment

The ATLAS experiment is without doubt one of the most important scientific endeavors at CERN, the European Group for Nuclear Analysis. It’s a key a part of the Giant Hadron Collider (LHC), the world’s largest and strongest particle accelerator. Situated close to Geneva, ATLAS stands for “A Toroidal LHC ApparatuS” and is concentrated on probing basic features of physics.

ATLAS was designed to discover a variety of scientific questions. It seeks to grasp the fundamental forces which have formed our universe because the starting of time and that may decide its destiny. Amongst its main targets is the investigation of the Higgs boson, the particle related to the Higgs discipline, which supplies different particles their mass. The invention of the Higgs boson in 2012, a joint effort by ATLAS and the CMS (Compact Muon Solenoid) experiment, was a landmark achievement in physics.

The experiment additionally searches for indicators of recent physics, together with the origins of mass, further dimensions, and particles that would make up darkish matter. ATLAS does this by analyzing the myriad particles produced when protons collide at almost the velocity of sunshine inside the LHC.

The ATLAS detector itself is a technological marvel. It’s huge in scale, about 45 meters lengthy, 25 meters in diameter, and weighs about 7,000 tonnes. The detector is made up of varied layers, every designed to detect various kinds of particles produced by the proton-proton collisions. It features a vary of applied sciences: trackers to detect the paths of particles, calorimeters to measure their vitality, and muon spectrometers to establish and measure muons, a sort of heavy electron that’s key to many physics investigations.

The info collected by ATLAS is immense, usually described when it comes to petabytes. This information is analyzed by a world neighborhood of scientists, contributing to our understanding of basic physics and probably resulting in new discoveries and applied sciences.