ANTIMATTER IN THE UNIVERSE: WHY AREN’T WE MADE OF ANTIMATTER?

Аннотация

According to the Big Bang theory, matter and antimatter must have been created in equal amounts during the earliest moments of the universe. However, the observable universe today consists almost entirely of ordinary matter, while traces of antimatter are extremely rare. This article explores the physical nature of antimatter, scientific perspectives on its presence in theuniverse, and modern hypotheses regarding thecauses ofmatter-antimatterasymmetry. Keywords:antimatter, Big Bang, asymmetry, CP violation,matter, annihilation,universe Every particle — for instance, an electron — has a corresponding “anti-particle.” For the electron, this is the positron, which has a positive charge; for the proton, it's the antiproton, with a negative charge. According to the laws of physics, matter and antimatter should have been produced in equal amounts during the Big Bang. Yet, modern observations show that the universeis composed almostentirely ofordinary matter. Antimatteris exceedingly scarce. This raises the critical question: If matter and antimatter were created equally, where did the antimatter go?Or putdifferently: Whyare wemadeof matter and notantimatter? In theory, matter and antimatter obey the same physical laws and should have been formed symmetrically, eventually annihilating one another. When a matter particle collides with its corresponding antimatter particle, they annihilate each other, releasing large amounts of energy — a process called annihilation. Despite this, the galaxies, stars, planets, and even the human body are composed of ordinary matter. No stars or galaxies composed of antimatter have yet been discovered. This contradiction remains one of the most fundamental mysteries in cosmology and particle physics. It is known as baryon asymmetry — the question of why matter dominates over antimatter, and where the antimatter has gone. Modern research, including observations of cosmic background radiation and high-energy particle experiments (such as those at CERN), is working to uncover theanswer to thispuzzle. This article discusses the nature of antimatter, various hypotheses concerning the asymmetry between matterand antimatter, and their implications forour understanding of theuniverse. TheNature ofAntimatter Antimatterissimilarto ordinary matterbut with oppositeelectric charges: •Electron ↔Positron •Proton↔Antiproton •Neutron ↔Antineutron When matter and antimatter collide, they annihilate each other in a process known as annihilation,producing pure energy (typically gammarays). 340 INTERNATIONAL MULTIDISCIPLINARY JOURNAL FOR RESEARCH & DEVELOPMENT SJIF2019:5.2222020:5.5522021:5.6372022:5.4792023:6.5632024:7,805 eISSN:2394-6334 https://www.ijmrd.in/index.php/imjrd Volume12,issue07(2025) In physics, this phenomenon is referred to as “baryon asymmetry” — that is, why is there morematter than antimatterin theuniverse? According to the Big Bang theory, during the first moments of the universe, for every 10billion antiparticles, there was 1 excess matter particle. After mutual annihilation of particles and antiparticles, only that tiny surplus of matter remained — which eventually formed everything weobserve in theuniverse today. But how did such a small imbalance arise in the first place? The exact cause remains unknown, yet several plausibleexplanationshave been proposed. Physicists suggest afew main hypotheses: 1. CP Violation. In theory, matter and antimatter should behave symmetrically. However, certain particles — such as kaons and B-mesons — have been observed to violate Charge (C) and Parity (P) symmetry. This phenomenon, known as CP violation, may have contributed to thedominance ofmatterover antimatter. 2. Leptogenesis and Baryogenesis. After the Big Bang, leptons (like electrons and neutrinos) and baryons (like protons and neutrons) may have formed in unequal quantities through processes known as leptogenesis and baryogenesis. These mechanisms could have favored matterover antimatter, contributing to theimbalance. 3. Absence of Antimatter Galaxies. If there were antimatter galaxies in the universe, we would expect intense gamma radiation at the boundaries between matter and antimatter regions due to annihilation. However, no such radiation has been observed, suggesting that antimatter is eitherextremely rare or completely absent oncosmicscales. Despitedecades of study, traces ofantimatter have not been found in theuniverse. This mystery remains one of the most profound questions in modern physics: Why, in a universe where matterandantimatter shouldhavebeen created equally, is matter so dominant? Understanding the answer to this question is not only crucial for fundamental physics but also forunderstanding theorigin oftheuniverse —and even ourown existence. The antimatter problem remains one of the most puzzling questions in modern cosmology. Theoretically, matter and antimatter should have been created in equal amounts during the Big Bang, but today we observe a universe composed almost