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Home , CLOUD experiment, LHCf experiment, MoEDAL experiment, NA48 experiment, Pionium

1) Mahantesh L Chikkadesai 2) Ramakrishna R Pujari [email protected] [email protected] Mobile no: +919480780580 Mobile no: +917411812551

Phy 009 Sub atomic and Phy 009 Sub atomic particles and developments in developments in cern

Electrical and Electronics Electrical and Electronics KLS’s Vishwanathrao deshpande rural KLS’s Vishwanathrao deshpande rural institute of technology institute of technology Haliyal, Uttar Kannada Haliyal, Uttar Kannada

SUB ATOMIC PARTICLES AND DEVELOPMENTS IN CERN

Abstract-This paper reviews past and present cosmic rays. Anderson discovered their existence; developments of sub atomic particles in CERN. It High-energy subato mic particles in the form gives the information of sub atomic particles and of cosmic rays continually rain down on the Earth’s deals with basic concepts of physics, atmosphere from outer space. classification and characteristics of them. Sub atomic More-unusual subatomic particles —such as particles also called , any of various self-contained units of or energy that the , the antimatter counterpart of the are the fundamental constituents of all matter. All of —have been detected and characterized the known matter in the universe today is made up of in cosmic-ray interactions in the Earth’s elementary particles ( and ), held atmosphere. together by fundamental forces which are Quarks and are some of the elementary represente d by the exchange of particles known as particles we study at CERN and in other gauge . is the theory that laboratories. But physicists have found more of describes the role of these fundamental particles and these elementary particles in various experiments. interactions between them, this is briefly reviewed Our best understanding of how these particles and and this standard model with its salient features described. T o understand how the universe evolved three of the forces are related to each other is we really need to understand the behaviour of encapsulated in the Standard Model of particle elementary particles: the quarks, leptons and gauge physics. Developed in the early 1970s, it has bosons. Since from 1954 several important successfully explained almost all experimental achievements in have been made results and precisely predicted a wide variety of during experiments at CERN, th ey have discovered phenomena. Over time and through many many particles. In this paper, several results of those experiments, the Standard Model has become experiments are described. established as a well-tested physics theory. Keywords: Elementary particles, Large

Collider, fundamental interactions, gauge , Fermi lab. I. INTRODUCTION The theories and discoveries of tho usands of physicists since the 1930s have resulted in a remarkable insight into the fundamental structure of matter: everything in the universe is found to be made from a few basic building blocks called fundamental particles. Small particles in the hierarchy of the universe were discovered and researched: these are commonly , that are constructed of , that in turn consist of subatomic particles, Thomson ha d discovered the first . A subatomic particle is a particle smaller than an : it may be elementary or composite. These particles include atomic constituents such as electrons, , and (protons and neutrons are actually c omposite particles, made up of quarks), as well as other particles such as and which are produced copiously in the sun. The concept of spin is now recognized as an intrinsic property of all subatomic particles. However, most of the particles that have been discovered and studied are not encountered under normal earth conditions; they are produced in Fig.1 evolution of sub atomic particles II. CERN • The ALPHA experiment is a successor of an earlier antimatter experiment. The European Organization for Nuclear Research e) AMS: known as CERN, whose purpose is to operate the • The Alpha Magnetic Spectrometer looks world's largest particle physics laboratory. for dark matter, antimatter and missing Established in 29 September 1954, the organization matter from a module on the International is based in the northwest suburbs of Geneva on the Space Station. Franco–Swiss border, and has twenty European • The Alpha Magnetic Spectrometer (AMS- member states. 02) is a particle-physics detector that looks CERN's main function is to provide the particle for dark matter, antimatter and missing accelerators and other infrastructure needed for matter from a module attached to the high-energy physics research. It is also the outside of the International Space Station birthplace of the World Wide Web. (ISS). It also performs precision measurements of cosmic rays. A. Experiments at CERN: f) ASACUSA: a) ACE: • The Atomic Spectroscopy And Collisions • The Cell Experiment (ACE) Using Slow (ASACUSA) started in 2003. It aims to assess fully the experiment studies the fundamental effectiveness and suitability of antiprotons symmetries between matter and antimatter for cancer therapy. • by precision spectroscopy of atoms ACE brings together an international team containing an antiproton (the antimatter of physicists, biologists and medics to equivalent of the ). The experiments study the biological effects of antiprotons. focused in particular on hybrid atoms • ACE is an excellent example of how (antiprotonic helium), ASACUSA research in particle physics can bring compares matter and antimatter using innovative solutions with potential atoms of antiprotonic helium and medical benefits. antihydrogen, and studies the properties of b) AEGIS: matter-antimatter collisions. • The primary scientific goal of the Anti g) ATLAS: hydrogen Experiment: Gravity, • ATLAS is one of two general-purpose Interferometry, Spectroscopy (AEGIS) is detectors at the the direct measurement of the Earth's (LHC). It investigates a wide range of gravitational acceleration, on physics, from the search for the Higgs antihydrogen. boson to extra dimensions and particles • AEGIS uses a beam of antiprotons from that could make up matter. From a cavern the to measure the 100 metres below a small Swiss village, value of Earth’s gravitational acceleration. the 7000-tonne ATLAS detector is The AEGIS experiment will represent the probing for fundamental particles. first direct measurement of a gravitational h) ATRAP: effect on an antimatter system. • ATRAP compares hydrogen atoms with their antimatter equivalents - antihydrogen atoms. The Antihydrogen trap (ATRAP) is an experiment to compare hydrogen atoms c) ALICE: with their antimatter equivalents – • ALICE detects - plasma, a antihydrogen atoms. In 2002, ATRAP state of matter thought to have formed just provided the first glimpse inside after the big bang. antihydrogen atoms after researchers • ALICE (A Large Ion Collider Experiment) successfully created and measured a large is a heavy-ion detector on the Large number of them. ATRAP was the first Hadron Collider (LHC) ring. It is designed experiment to use cold to cool to study the physics of strongly interacting antiprotons. matter at extreme energy densities, where i) AWAKE: a phase of matter called quark-gluon • AWAKE explores the use of plasma to plasma forms. accelerate particles to high energies over d) ALPHA: short distances. • ALPHA makes, captures and studies j) CAST: atoms of antihydrogen and compares them • The CERN Solar Telescope with hydrogen atoms. (CAST) is an experiment to search for hypothetical particles called "". These have been proposed by some theoretical physicists to explain why and neutrons that form the nuclei of there is a subtle difference between matter ordinary atoms. and antimatter in processes involving the • A collaboration of CERN physicists are weak force, but not the strong force. If studying the decay of unstable “pionium axions exist, they could be found in the atoms” to gain insight into the strong centre of the Sun and they could also force. make up invisible dark matter. o) ISOLDE: • Hypothetical particles called axions could • ISOLDE studies the properties of atomic explain differences between matter and nuclei, with further applications in antimatter - and we may find them at the fundamental studies, astrophysics, centre of the Sun. material and life sciences The Isotope k) CLOUD: mass Separator On-Line facility • The Cosmics Leaving Outdoor Droplets (ISOLDE) is a unique source of low- (CLOUD) experiment uses a special cloud energy beams of radioactive nuclides, chamber to study the possible link those with too many or too few neutrons between galactic cosmic rays and cloud to be stable. It permits the study of the formation. Based at the Proton vast territory of atomic nuclei, including Synchrotron (PS) at CERN, this is the first the most exotic species. time a high-energy physics accelerator has p) LHCb: been used to study atmospheric and • The LHCb experiment will shed light on climate science. The results should why we live in a universe that appears to contribute much to our fundamental be composed almost entirely of matter, but understanding of aerosols and clouds, and no antimatter. their affect on climate. q) LHCf: • Could there be a link between galactic • The LHCf experiment uses particles cosmic rays and cloud formation? An thrown forward by LHC collisions to experiment at CERN is using the cleanest simulate cosmic rays. box in the world to find out r) MOEDAL: l) CMS: • The MOEDAL experiment is looking for a • The CMS detector uses a huge solenoid hypothetical particle with magnetic magnet to bend the paths of particles from charge: the . collisions in the LHC. The Compact • The MOEDAL collaboration has built a Solenoid (CMS) is a general-purpose detector to search for this particle. detector at the Large Hadron Collider (LHC). • It is designed to investigate a wide range of physics, including the search for the B. SCIENTIFIC ACHIVEMENTS: , extra dimensions, and Several important achievements in particle physics particles that could make up dark matter have been made during experiments at CERN. The CMS detector is built around a huge They include: solenoid magnet. m) COMPASS: • • The Common Muon and Proton Apparatus 1983: The discovery of in for Structure and Spectroscopy the UA1 and UA2 experiments • (COMPASS) experiment is a 1989: The determination of the number of multipurpose experiment at CERN’s light families at the Large Electron– Super Positron Collider (LEP) operating on the Z (SPS).COMPASS investigates how quarks boson peak • and interact to give the particles we 1995: The first creation of antihydrogen atoms observe. in the PS210 experiment n) DIRAC: • 1999: The discovery of direct CP violation in • The Dimeson Relativistic Atom Complex the NA48 experiment (DIRAC) is an experiment to help • 2010: The isolation of 38 atoms physicists gain a deeper insight into the of antihydrogen fundamental force called the strong force. • 2011: Maintaining antihydrogen for over 15 This plays a crucial role in particle minutes physics, as it binds together the particles • 2012: A boson with mass around 125 called quarks, which in turn make up GeV/c 2 consistent with long-sought Higgs many other particles, including the protons boson.

c. The is a single or discrete electromagnetic wave. III. CLASSIFICATION d. The last particle required is an electrically neutral particle called the neutrino. Neutrinos do not exist within atoms; these are weakly interacting elementary subatomic p article with half -integer spin. e. Neutrinos are affected only by the weak subatomic force, and they are not affected by electromagnetic force. f. The study of neutrinos is important in particle physics because neutrinos typically have the lowest mass. g. Neutrinos do not carry electric charge . h. And another important t hing is that, beta decays are important in the transitions that occur when unstable atomic nuclei change to become more stable, and for this reason neutrinos are a necessary component in establishing the nature of matter.

Fig.2 classification of elementary particles

A. QUARKS:

Theorists Gell-Mann and Zweig independently proposed a theory in 1964, and gave the information of these quarks. Quarks come in six varieties: a. Up (u), down (d), charm ( c), strange (s), top (t), and bottom (b). b. Quarks also have Antimatter counterparts Fig.3 A top-antitop quark event from D-zero called antiquarks (designated by a line detector at Fermi lab. over the letter symbol). • Quarks and gluons are combined to form c. Quarks combine to form heavier particles at t = 10–6 s after the big bang. called , and quarks and antiquarks In addition to such familiar particles as the proton, combine to form . , and electron, studies have slowly revealed the existence of more than 200 other subatomic particles. B. LEPTONS: C. BOSONS: a. Leptons are a group of subatomic particles a. These are the particles which give the that do not experience the strong force. mass to the matter and the particles with b. The family is comprised of the well zero or integer spin quantum numbers are known electron and its two bigger but called boson. Which have the spin s -1, and highly unstable brother s, the muon and these are also known as god particles. . b. W and Z bosons ar e weak bosons or intermediate vector bosons . c. W bosons have a positive and negative electric charge of 1 elementary charge respectively and are each other’s . d. Z bosons are electrically neutral and are its own . The W and Z bosons ar e carrier particles that mediate the weak nuclear force; much like the photon is the carrier particle for the electromagnetic force. e. Sheldon Glashow, Steven Weinberg, and Abdus Salam, shared the 1979 Nobel Prize in Physics. Their.00 electroweak theory post ulated not only the W bosons necessary to explain beta decay, but also new Z boson that had never been observed. f. The fact that the W and Z boson have mass while photons are mass less was a major obstacle in developing electroweak theory. g. The W and Z bosons decay to - antifermion pairs but neither the W nor Z bosons can decay into the higher mass top Fig.4 Standard Model • quark. On 4 July 2012, the ATLAS and CMS IV. STANDARD MODEL: experiments at CERN's Large Hadron a. The Standard Model explains how the Collider (LHC) announced they had each basic building blocks of matter interact, observed a new particle in the mass region governed by four fundamental forces around 126 GeV. This particle is b. The theories and discoveries of thousands consistent with the Higgs boson but it will of physicists since the 1930s have resulted take further work to determine whether or in a remarkable insight into the not it is the Higgs boson predicted by the fundamental structure of matter: Standard Model. • c. Everything in the universe is found to be Higgs bosons are predicted by other made from a few basic building blocks theories t hat go beyond the Standard called fundamental particles, govern ed by Model. four fundamental forces. Our best • The “standard model” of particle physics d. Understanding of how these particles and is a system that attempts to describe the three of the forces are related to each other forces, components, and reactions of the is encapsulated in the Standard Model of basic particles that make up matter. It not particle physics. Developed in the early only deals with atoms and their 1970s, it has successfully explained components, but the pi eces that compose almost al l experimental results and some subatomic particles. precisely predicted a wide variety of • This model does have some major gaps, phenomena. Over time and through many including gravity, and some experimental experiments, the Standard Model has contradictions. The standard model is still become established as a well -tested a very good method of understanding physics theory. particle physics, and it continues to e. Standard Model includes the improve. electromagnetic, strong and weak forc es • The m odel predicts that there are certain and all their carrier particles, and explains elementary particles even smaller than well how these forces act on all of the protons and neutrons. As of the date of matter particles. this writing, the only particle predicted by the model which has not been experimentally verified is the “Higgs boson,” jokingly referred to as the “God particle.” • On 8 October 2013 the Nobel Prize in [9] Laura Reina, “Higgs Boson Physics, Part physics was awarded jointly to François I”, TASI 2004, Boulder. Englert and Peter Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider." • So although the Standard Model accurately describes the phenomena within its domain, it is still incomplete. Perhaps it is only a part of a bigger picture that includes new physics hidden deep in the subatomic world or in the dark recesses of the universe. New information from experiments at the LHC will help us to find more of these missing pieces. V. CONCLUSION By knowing these all things we come to know that, since from the beginning of the 20 th century study and research about the sub atomic particles and their behaviour have taken very important role in the development of modern physics and technology. But still the new experiments about sub atomic particles are going on in various parts of the world. Knowledge about the sub atomic particles gives us the information about origin of universe. Despite all its successes, many questions unanswered by Standard Model. – Why 3 generations, particle masses, why do the generations mix, anti-matter v/s Matter. Still more questions than answers! VI. REFRENCES [1] Halliday, Resnick, Walker, “Fundamentals of physics”, p 1116-1130 [2] Walter R. Johnson, “Lectures on Atomic Physics”, Department of Physics, University of Notre Dame. [3] Nari Mistry, “A brief introduction to particle physics”, Laboratory for Elementary Particle Physics Cornell University. [4] Journal of Modern Physics ISSN: 2153- 120X, “Special Issue on Neutrino Research”, Scientific Research Open Access. [5] Joseph Lykken and Maria Spiropulu, “The future of the Higgs boson”, Physics Today, AIP Publishing. [6] Nick Hadley, “The Standard Model or Particle Physics 101”. [7] History of subatomic physics, From Wikipedia, the free encyclopedia. [8] Perspectives on Subatomic Physics in Canada for2006-2016report of the “NSERC long-range planning committee”.