Inside the World of Particle Accelerators: How CERN is Rewriting Physics

 Research lead by: Sameer Farrukh

Writers: Rayan Inayat, Ali Abdullah, Ibrahim, Maryam Waseem

Introduction:

“The most incomprehensible thing about the universe is that it is comprehensible.” — Albert Einstein`

Human nature has always led usto curiosity even about the deepest matters of the universe whether that is thestars beyond our reach or matter smaller than dust. With the world goingthrough rapid scientific advancements physicists discovered a new hidden worldof matter composed of increasingly small particles. Now how do you dive intosomething so minute, so infinitesimal?.This gave birth to one of the mostimportant creations by the scientists of the 1900s; Particle accelerators.A phenomena designed to show the structure of matter through mimickingconditions present right after the start of the universe.

How do scientists replicatesuch extreme conditions? Particle accelerators are designed to increase thespeed and energy of charged particles using electromagnetic fields . Byincreasing their speed it becomes easier to probe the particle's structure andobserve matters at subatomic levels. These high energy and speed levels arereached through magnetic fields helping the particles to move forward and controltheir direction. In modern particle accelerators, charged particles areaccelerated to relativistic velocities, often exceeding 99.999999% of thespeed of light at which particles are directed towards a fixed target orcollide with each other. These high energy collisions are observed and studiedby physicists. (“How Particle Accelerators Work” 2014) (Holzer 2017, #)

History:

In order to understand thehistory of particle accelerators we'd first have to go back to the late 1800sand the start of the 20th century. The origin of particles in the world ofphysics starts with the assumption that atoms were invisible until the electronwas discovered by JJ.Thomasan in 1897 which concluded thatparticles had internal structure. This led to further studies and in 1911Ernest Rutherford discovered the center of an atom, the nucleus. To studysuch subatomic particles required high speeds which directly led to thedevelopment of particle accelerators.The development of particle acceleratorscan be divided into three stages. (Sutton 2025)

The decades 1920-1930 markedthe first and second generation of the development of particle acceleratorswhich started with making use of static fields to accelerate charged particles.Though at that time the maximum energy was limited because of high voltagecausing electrical breakdown. In 1931 the cyclotron introduced anew method to overcome this limitation using circular motion. In 1932 JohnCockcroft and Ernest Walton built the first particle acceleratorwhich was named after them; Cockcroft-Walton which was successful incausing the first artificial nuclear reaction. (Sutton 2025)

The third stage, Synchrotrons,was developed in the 1940s as a result of the limits of early cyclotrons,primarily the relativistic effects that reduced productivity at very highspeeds. These devices allowed for far faster, relativistic speeds by adjustingmagnetic and electric fields in accordance with particle energy. Even Largeraccelerators were constructed after World War II, but growing size and expensewere major obstacles. Despite these drawbacks, this advancement turnedaccelerators from tiny lab instruments into massive machines necessary forresearching the basic structure of matter. (Sutton 2025)

Why dowe build particle accelerators

Particleaccelerators are among the most sophisticated scientific tools ever developed,enabling physicists to explore the fundamental composition of matter and theforces that shape the universe. By accelerating subatomic particles to near lightspeeds and causing them to collide, researchers can observe rare interactionsthat help discover new particles and laws of physics. CERN, the EuropeanOrganization for Nuclear Research, operates the world’s largest particleaccelerator and is a leader in high-energy physics research. This sectionexplores why these accelerators are built and how CERN's experiments andtechnologies are advancing modern physics. A particle accelerator utilizeselectromagnetic fields to propel charged particles, such as protons orelectrons, to extremely high speeds, often approaching the speed of light.These particles are then directed to collide with a fixed target or otherbeams. Detectors record the energy, momentum, and decay patterns from thesecollisions for analysis. Primarily, particle accelerators aim to answerfundamental questions in physics. They enable scientists to examine smallerscales of matter than normally possible, uncovering particles and interactionsbeyond everyday observation. They also test theoretical models such as theStandard Model. The construction of particle accelerators is driven byessential scientific and technological reasons, understanding these reasonshelps clarify how they function. First, accelerators identify elementaryparticles and study their interactions through fundamental forces. Furthermore,many physical theories make precise predictions that require experimentalvalidation, which accelerators provide by recreating extreme conditions. Whenresults differ from expectations, new physics may be indicated. Additionally,these collisions temporarily recreate conditions similar to those just afterthe Big Bang, aiding the understanding of the universe's origin and evolution.Beyond basic science, accelerator technology has led to applications in medicalimaging, cancer treatment, materials analysis, and computing advancements.CERN, founded in 1954 on the Switzerland-France border, is an internationalresearch organization dedicated to exploring the universe's fundamental naturethrough particle physics. It promotes global collaboration and technologicalinnovation, uniting thousands of scientists and engineers. CERN designs,builds, and runs some of the most complex scientific instruments ever made.CERN's flagship facility is the Large Hadron Collider (LHC), the world’slargest particle accelerator. It consists of a 27-kilometer underground circlewhere two proton beams are accelerated in opposite directions withsuperconducting magnets. These beams collide at specific points equipped withdetectors. The LHC played a pivotal role in discovering the Higgs boson in2012, confirming a key part of the Standard Model and explaining how particlesacquire mass. Current research includes searching for dark matter, newparticles, and phenomena beyond current theories. CERN also plans upgrades likethe High-Luminosity LHC to increase collision rates and measurement precision,aiming to address unresolved questions in physics. Particle accelerators remainvital tools for probing the universe's fundamental aspects. They allow testingtheories, discovering new particles, and recreating extreme conditionsimpossible elsewhere. Through its continued operation, CERN remains at theforefront of this scientific frontier.

The Discovery of the Higgs Boson(Particle)

The Higgsboson is a fundamental particle that plays a crucial role in our understandingof how matter in the universe acquires mass. It is associated with the Higgsfield, an invisible field that permeates all of space and interacts with elementaryparticles. As particles move through this field, they gain mass depending onhow strongly they interact with it, which explains why some particles areheavier than others while some remain massless. The Higgs boson itself is notresponsible for giving particles mass; instead, it is a measurable sign of theHiggs field’s existence, providing experimental confirmation of a keytheoretical concept in particle physics.

Asunderstanding of fundamental particles developed during the twentieth century, physicistsassembled what is now known as the Standard Model of particle physics, a theorythat successfully describes the basic components of matter and theirinteractions. However, by the early 1960s, a critical gap remained; the theorycould not explain why particles possess mass without violating its ownmathematical structure. To resolve this problem, physicists proposed theexistence of the Higgs field and its associated particle, later called theHiggs boson. Although the idea quickly became central to the Standard Model,the particle itself remained undetected for nearly fifty years, motivatingdecades of experimental effort aimed at confirming its existence.

Thediscovery of the Higgs boson was announced in 2012 after decades of theoreticalresearch and experimental preparation at CERN. Recognizing that its detectionwould require unprecedented technology, scientists designed and built the LargeHadron Collider (LHC), the most powerful particle accelerator ever constructed,through a major international collaboration and significant financialinvestment. The LHC was created to explore fundamental questions about theorigin of mass and the structure of matter by colliding protons at extremelyhigh energies, recreating conditions similar to those just after the Big Bang.Two major experiments, ATLAS and CMS, independently examined the vast datagenerated by these collisions. Through years of careful data analysis, bothteams identified consistent signals that matched longstanding theoreticalpredictions, ultimately confirming the existence of a new particle andproviding strong evidence for the Higgs boson.

Theconfirmation of the Higgs boson was a historic milestone in physics, completingthe Standard Model and validating decades of theoretical work. By revealing howfundamental particles acquire mass, it basically provided profound insight intothe structure of the universe. So influential was this particle that it becamepopularly known as the “God Particle,” a name that highlights how important itis and how it has captured people’s imagination around the world. Beyond itsscientific and philosophical importance, the discovery highlighted the power oflarge-scale international collaboration and cutting-edge technology, drivinginnovations such as the World Wide Web, advanced data storage systems, andhigh-speed networks capable of handling CERN’s enormous experimental datasets.The breakthrough was recognized globally, culminating in the 2013 Nobel Prizein Physics awarded to Francois Englert and Peter Higgs, the scientists whofirst proposed the mechanism that now bears their names.

Scientists Current Research at CERN

Even after its discovery,the Higgs boson continues to be a focus of intense research at CERN. Scientistsare studying its properties in ever greater detail, including its mass,stability, and how it interacts with other particles. These measurements helpverify whether the Higgs behaves exactly as predicted by the Standard Model orif subtle deviations could point to new physics beyond the current theory.Studying the Higgs also opens new pathways to explore unanswered questions inphysics, from the nature of dark matter to the origins of the universe itself,offering a deeper understanding of the cosmos and guiding future discoveries. Bypushing the limits of precision, researchers hope to uncover insights thatcould reshape our understanding of the fundamental laws of nature.

To deepen thestudy of the Higgs boson and other fundamental particles, CERN is upgrading theLarge Hadron Collider to the High-Luminosity LHC, which will dramaticallyincrease the number of proton collisions. Higher collision rates allowscientists to observe even the rarest particle interactions, improving theprecision of their measurements and testing the Standard Model more rigorously.Alongside this, upgraded detectors and advanced data-analysis systems are beingimplemented to capture and process the enormous volumes of data with greateraccuracy, opening the door to potential discoveries beyond current theories.

Beyond theHiggs boson, CERN continues to explore some of the universe’s biggestquestions. Scientists are searching for dark matter, studying antimatter, andinvestigating new particles that could reveal physics beyond the StandardModel. These experiments expand our understanding of the cosmos andopenpossibilities for discoveries that could reshape fundamental physics.

Future of particle accelerators

Futureaccelerators will play a major role in the future, and they are already indevelopment. It involves next-generation colliders, such as the CERN(European Council for NuclearResearch) Future Circular Collider, andplasma wakefield acceleration, which is sustainable and adaptable.  PWFA works by injecting a proton beam into along plasma source, which drives wave fields. Electrons are also added, andwhen they are on, they are accelerated at a very high energy, corresponding tothe correct wave. Its adaptability enables it to have numerous medicalapplications, including cancer treatments. It produces X-rays and protons todestroy tumour cells. The light produced can also be used to break the proteinstructure, which is used in pharmaceuticals. The FCC involves 3 sections.‘’FCC-hh, for hadron-hadroncollisions, including proton-protonand heavy ion collisions, FCC-ee, forelectron-positroncollisions, and FCC-eh, for electron-hadron collisions.’’ It aims to investigatethe nature of dark matter and the Higgs field. The technology used inaccelerators is also used in proton therapy and hadron therapy, which directlytreat tumours. Other projects are also being worked on; one of them is the muoncollider. This collider uses muons instead of electrons and protons. Muoncolliders are also known as the ‘’ compact powerhouse, " as they are moresustainable and lose less energy when compared to electrons because they aremuch heavier and thus allow them to move in circular paths without emittingmassive amounts of radiation. In a proton collision, energy is wasted amonginternal quarks. Another project which is being worked on is the (ccm ) theCircular Collider on the Moon; its construction is based on the great circle onthe Moon. The materials that are required to construct the machine areavailable on the moon. This project may take several decades or centuries inthe future; there will be no radiation and safety problems, and it will drivenew technology and science. Moreover, over12000 accelerators are used to dope silicon chips with specific ions,making the advanced processors in your 2025 smartphone and electric car possible. The nuclear reactors built in the 1960s arescheduled to be shut down by the 2030s and replaced by the accelerators becausethey tend to produce less radiation and do not use uranium.

References

Holzer, B. J. 2017.“Introduction to Particle Accelerators and their Limitations.” https://arxiv.org/abs/1705.09601v1,(5), 22. https://doi.org/10.5170/CERN-2016-001.29.

“How Particle AcceleratorsWork.” 2014. Department of Energy.https://www.energy.gov/articles/how-particle-accelerators-work.

Sutton, Christine. 2025.“Particle accelerator - Cyclotrons, Particles, Physics.” Britannica.https://www.britannica.com/technology/particle-accelerator/Cyclotrons.

Sutton, Christine. 2025.“Particle accelerator | Definition, Types, History, & Facts.” Britannica.https://www.britannica.com/technology/particle-accelerator#ref60507.

Sutton,Christine. 2025. “Particle accelerator - Synchrotrons, Particles, Physics.”Britannica. https://www.britannica.com/technology/particle-accelerator/Synchrotrons.

https://cds.cern.ch/record/1997220.Accessed 18 December 2025. https://ats.web.cern.ch/. Accessed 20 December 2025.“[1901.09966] Physics Beyond Colliders at CERN: Beyond the Standard ModelWorking Group Report.” arXiv , 20 January 2019,https://arxiv.org/abs/1901.09966. Accessed 20 December 2025. “Accelerators.” CERN, https://home.cern/science/accelerators. Accessed 20 December 2025. Beall,Abigail. “Large Hadron Collider discovers five hidden subatomic particles.” WIRED, 21 March 2017, https://www.wired.com/story/lhc-five-subatomic-particles.Accessed 20 December 2025. Charisopoulos, Sotirios. “What Are ParticleAccelerators?” International Atomic Energy Agency , 8 September 2023,https://www.iaea.org/newscenter/news/what-are-particle-accelerators. Accessed18 December 2025. “DOE Explains...Particle Accelerators.” Department ofEnergy , https://www.energy.gov/science/doe-explainsparticle-accelerators.Accessed 19 December 2025. “Particle accelerator - Wikipedia.” Wikipedia,the free encyclopedia , https://en.wikipedia.org/wiki/Particle_accelerator.Accessed 19 December 2025.

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