ZME Science
No Result
View All Result
ZME Science
No Result
View All Result
ZME Science

Home → Science → News

Two new subatomic particles discovered at CERN, as predicted by Standard Model

Tibi PuiubyTibi Puiu
November 19, 2014 - Updated on May 14, 2021
in News, Physics
A A
Share on FacebookShare on TwitterSubmit to Reddit

RelatedPosts

Fastest network data transfer in the world – 186 GB/s
Rumors of imminent Higgs boson announcement run amok on science blogs. Discovery might be announced next week
CERN found a new particle — a tetraquark
CERN to re-do the neutrino speed test

While the LHC at CERN is gearing up for its long-awaited restart, following an overhaul, scientists aren’t standing idle. After analyzing collision data made during 2011-2012, physicists have identified two new baryons, known as the Xi_b‘- and Xi_b*-. The new subatomic particles’ properties match predictions based on the theory of Quantum Chromodynamics (QCD), a subset of the Standard Model of particle physics – the governing theory that describes the fundamental particles of matter, how they interact, and the forces between them.

Three quarks, one baryon, two new particles

View of the CMS detector at the end of 2007. (Maximilien Brice, © CERN)
View of the CMS detector at the end of 2007. (Maximilien Brice, © CERN)

Baryons are composite particles comprising three quarks bound together by the so-called strong force. As such, protons (two up and one down) and neutrons (one up quark and two down quarks) are also baryons. Since there are six flavors of quarks (and six anti-quarks), baryons can combine in numerous renditions. It’s no surprise, with this in mind, that baryons comprise most of the visible matter.

The new Xib particles confirmed at CERN, being baryons, are also comprised of three quarks as follows:

  • both contain one beauty (b), one strange (s), and one down (d) quark;
  • yet they differ by spin – a fundamental attribute for any particle;
  • in the Xi_b‘- state, the spins of the two lighter quarks point in opposite directions, whereas in the Xi_b*- state they are aligned. This difference makes the Xi_b*- a little heavier.
  • each of the Xib particles is, on average, six times as massive as the proton.

“Nature was kind and gave us two particles for the price of one,” said Matthew Charles of the CNRS’s LPNHE laboratory at Paris VI University. “The Xi_b‘- is very close in mass to the sum of its decay products: if it had been just a little lighter, we wouldn’t have seen it at all using the decay signature that we were looking for.”

“This is a very exciting result. Thanks to LHCb’s excellent hadron identification, which is unique among the LHC experiments, we were able to separate a very clean and strong signal from the background,” said Steven Blusk from Syracuse University in New York. “It demonstrates once again the sensitivity and how precise the LHCb detector is.”

Why this is important for physics

The mass difference spectrum: the LHCb result shows strong evidence of the existence of two new particles the Xi_b'- (first peak) and Xi_b*- (second peak), with the very high-level confidence of 10 sigma. The black points are the signal sample and the hatched red histogram is a control sample. The blue curve represents a model including the two new particles, fitted to the data. Delta_m is the difference between the mass of the Xi_b0 pi- pair and the sum of the individual masses of the Xi_b0 and pi-. INSET: Detail of the Xi_b'- region plotted with a finer binning.
The mass difference spectrum: the LHCb result shows strong evidence of the existence of two new particles the Xi_b’- (first peak) and Xi_b*- (second peak), with the very high-level confidence of 10 sigmas. The black points are the signal sample and the hatched red histogram is a control sample. The blue curve represents a model including the two new particles, fitted to the data. Delta_m is the difference between the mass of the Xi_b0 pi- pair and the sum of the individual masses of the Xi_b0 and pi-. INSET: Detail of the Xi_b’- region plotted with a finer binning.

Besides mass, the researchers also looked at important decay parameters like width, which is a measure of how unstable the particle is. The most important part of the experiment is that scientists have confirmed the subatomic particles’ existence in the first place.

“If we want to find new physics beyond the Standard Model, we need first to have a sharp picture,” said LHCb’s physics coordinator Patrick Koppenburg from Nikhef Institute in Amsterdam. “Such high precision studies will help us to differentiate between Standard Model effects and anything new or unexpected in the future.”

Scientific reference

Tags: baryoncernstandard model

ShareTweetShare
Tibi Puiu

Tibi Puiu

Related Posts

News

CERN Creates Gold from Lead and There’s No Magic, Just Physics

byMihai Andrei
1 week ago
News

This Bold New Theory Could Finally Unite Gravity and Quantum Physics

byTibi Puiu
1 week ago
News

Astronomers Shocked as JWST Uncovers Massive Galaxies That Challenge Gravity Theory. Is Dark Matter Theory Wrong?

byTibi Puiu
6 months ago
News

The Milky Way’s place in the universe just got much bigger: It’s part of a cosmic superstructure beyond our wildest expectations

byTibi Puiu
7 months ago

Recent news

The Worm That Outsourced Locomotion to Its (Many) Butts

May 16, 2025

The unusual world of Roman Collegia — or how to start a company in Ancient Rome

May 16, 2025
Merton College, University of Oxford. Located in Oxford, Oxfordshire, England, UK. Original public domain image from Wikimedia Commons

For over 500 years, Oxford graduates pledged to hate Henry Symeonis. So, who is he?

May 16, 2025
  • About
  • Advertise
  • Editorial Policy
  • Privacy Policy and Terms of Use
  • How we review products
  • Contact

© 2007-2025 ZME Science - Not exactly rocket science. All Rights Reserved.

No Result
View All Result
  • Science News
  • Environment
  • Health
  • Space
  • Future
  • Features
    • Natural Sciences
    • Physics
      • Matter and Energy
      • Quantum Mechanics
      • Thermodynamics
    • Chemistry
      • Periodic Table
      • Applied Chemistry
      • Materials
      • Physical Chemistry
    • Biology
      • Anatomy
      • Biochemistry
      • Ecology
      • Genetics
      • Microbiology
      • Plants and Fungi
    • Geology and Paleontology
      • Planet Earth
      • Earth Dynamics
      • Rocks and Minerals
      • Volcanoes
      • Dinosaurs
      • Fossils
    • Animals
      • Mammals
      • Birds
      • Fish
      • Amphibians
      • Reptiles
      • Invertebrates
      • Pets
      • Conservation
      • Animal facts
    • Climate and Weather
      • Climate change
      • Weather and atmosphere
    • Health
      • Drugs
      • Diseases and Conditions
      • Human Body
      • Mind and Brain
      • Food and Nutrition
      • Wellness
    • History and Humanities
      • Anthropology
      • Archaeology
      • History
      • Economics
      • People
      • Sociology
    • Space & Astronomy
      • The Solar System
      • Sun
      • The Moon
      • Planets
      • Asteroids, meteors & comets
      • Astronomy
      • Astrophysics
      • Cosmology
      • Exoplanets & Alien Life
      • Spaceflight and Exploration
    • Technology
      • Computer Science & IT
      • Engineering
      • Inventions
      • Sustainability
      • Renewable Energy
      • Green Living
    • Culture
    • Resources
  • Videos
  • Reviews
  • About Us
    • About
    • The Team
    • Advertise
    • Contribute
    • Editorial policy
    • Privacy Policy
    • Contact

© 2007-2025 ZME Science - Not exactly rocket science. All Rights Reserved.