The Standard Model describes the fundamental particles of matter.
The Large Hadron Collider ( LHC ) is the largest and most powerful particle accelerator in the world. It is located at CERN (European Organization for Nuclear Research) , near Geneva, on the border between Switzerland and France. Its main purpose is to collide beams of hadrons, which are subatomic particles like protons, at high energies to study the fundamental interactions of matter. These collisions allow scientists to investigate properties of subatomic particles and test theories in particle physics, such as the Standard Model, and search for new particles, such as the Higgs boson , discovered in 2012.
Standard Model
The Standard Model of particle physics is the theory that describes the fundamental particles that make up matter and the forces that govern them, except gravity. It is based on three families of particles:
- quarks : components of protons and neutrons;
- leptons – include electrons, muons, taus and their associated neutrinos;
- gauge bosons : mediators of the fundamental forces ( photon for the electromagnetic force, gluons for the strong force, W and Z bosons for the weak force).
Additionally, the Higgs boson, discovered in 2012, gives particles mass through the Higgs field .
Physics beyond the Standard Model
Although the Standard Model has been extremely successful, it does not explain everything. Some of the problems and areas of research beyond this include:
- dark matter : invisible component of the universe that does not interact with light and is detected only through its gravitational influence;
- dark energy : responsible for the acceleration of the expansion of the universe;
- quantum gravity : unification of gravity with the other quantum forces;
- matter-antimatter asymmetry : explanation of why there is more matter than antimatter in the universe;
- Neutrinos : Their masses and oscillations are not fully explained within the Standard Model.
These areas suggest the existence of new particles, forces and physical principles that have not yet been discovered.
Quantum physics
In the context of the Large Hadron Collider, quantum physics plays a fundamental role in understanding and describing the observed phenomena.
Quantum phenomena
Quantum physics describes nature at the smallest scales, where subatomic particles exhibit behaviors that are not observed in the macroscopic world. Among the most relevant quantum phenomena are:
- superposition : particles can exist in multiple states at once until they are observed;
- entanglement : particles can be interconnected in such a way that the state of one instantly affects the state of another, regardless of the distance between them;
- Wave-particle duality : Subatomic particles, such as electrons and photons, exhibit properties of both particles and waves.
Quantum chromodynamics (QCD)
Quantum chromodynamics is the theory that describes the strong interaction, one of the four fundamental forces of nature. Its key points include:
- gluons : the mediator particles that transmit the strong force between quarks;
- confinement : quarks and gluons cannot be isolated. They are always confined within larger particles like protons and neutrons;
- free asymptoticity : at high energies, quarks and gluons interact weakly, allowing them to be studied in high-energy collisions such as those produced at the LHC.
Quantum electrodynamics (QED)
Quantum electrodynamics is the theory that describes electromagnetic interaction, which is responsible for almost all electromagnetic phenomena. Its key concepts include:
- photons : the mediating particles of the electromagnetic force;
- charged particle interaction – QED describes how charged particles, such as electrons and positrons, interact through the exchange of photons;
- radiative corrections : QED allows the effects of quantum fluctuations on electromagnetic interactions to be calculated with great precision.
At the Large Hadron Collider, these quantum theories are tested by colliding particles at extremely high energies . Quantum phenomena manifest themselves in the creation of new particles and in the interaction of quarks and gluons according to the rules of QCD and QED. These experiments not only verify the Standard Model, but also look for signs of new physics beyond this theoretical framework.
Simulation of dark matter in the cosmos: the invisible substance that makes up most of the universe.
Particle detectors
Particle detectors are devices used in particle physics to identify and measure properties of subatomic particles such as electrons, protons, neutrons and quarks. They are essential for experiments in particle accelerators such as the Large Hadron Collider, as they allow the results of particle collisions to be observed and recorded.
The particle detectors at the LHC are designed for different purposes and specialize in different types of collisions and particles. The main detectors at the LHC are ATLAS, CMS, ALICE and LHCb, each with its particular focus.
ATLAS Detector (A Toroidal LHC ApparatuS)
One of two general purpose detectors, along with CMS, and the largest. It is designed to explore a wide variety of physics topics, from the search for the Higgs boson to the study of supersymmetric particles and the analysis of dark matter.
ATLAS uses a toroidal magnetic field to bend the trajectories of charged particles and thus measure their moments.
CMS Detector (Compact Muon Solenoid)
The other general purpose detector at the LHC. Similar to ATLAS, CMS is designed to investigate a wide range of physical phenomena, such as the search for the Higgs boson, dark matter, and extra dimensions.
Unlike ATLAS, CMS uses a superconducting solenoid to create a strong, uniform magnetic field that allows the trajectories of charged particles to be accurately measured.
ALICE Detector (A Large Ion Collider Experiment)
Specifically designed to study collisions of heavy ions, such as lead. Its main goal is to investigate the properties of quark-gluon plasma, a state of matter that existed just after the Big Bang.
ALICE has a series of specialized subdetectors to handle the high density of particles produced in these collisions.
Albert Einstein: his theories laid the foundation for modern physics and research at the Large Hadron Collider
LHCb detector (Large Hadron Collider beauty)
Designed to study particles that contain bottom quarks ( beauty quarks ), and thus investigate the differences between matter and antimatter. This is crucial to understanding the asymmetry of the universe and why matter prevails over antimatter.
LHCb has a different configuration than ATLAS and CMS, as it is optimized to detect particles at low angles to the collision beam.
Each of these detectors plays a crucial role in the success of the Large Hadron Collider, allowing scientists to explore a wide variety of physical phenomena and expand our understanding of the universe at the subatomic level .