TheImpacts of Large Hadron Collider to the field of Physics
Particlephysics deals with the study of the smallest intricate objects ofnature. A few samples of these particles that are being deal withphysicists includes the atom (10-10m), nucleus (10-14m) and quarks (less than 10-19m) (Ekeren, 2013). Dealing with particle physics involves studyingthe smallest and fundamental particles that go way back into themoments after the Big Bang. As a way to explore how the Universeevolved to what is in existence now, EuropeanOrganization for Nuclear Research (CERN) built the most powerfulparticle accelerator from 1998 to 2008 – the Large Hadron Collider(LHC) (STFC, n.d.). LHC is the last element of the chain ofaccelerator complex at CERN. The accelerator complex is made up ofsequence of machines with increasing higher energies (CERN, 2009). Inthe LHC, each particle beam injected is accelerated up to 7 TeV(electronvolt) of energy. The LHC is composed of differentexperimental halls which are intended for different purposes whichwill be discussed further in this paper. Physicists believes that theenergy density and temperature data gathered from the collisionexperiments at the LHC will be able to demonstrate what existedwithin the moments after the Big Bang. They recreate and simulatethese experiments inside the 27 km accelerator through beam collisionof beams of high-energy protons or ions which is at the same rate asthe speed of light (STFC, n.d. US/LHC, 2012).
Thepurpose of the LHC is to let physicists prove the theories ofparticle and high-energy physics as well as to determine theexistence of the speculated Higgs particle and a new family ofparticles as projected from the supersymmetric theories. Theaccurateness of these principles formulated which is considered thefoundation of Modern Physics can be proven by the experiments basedon the Large Hadron Collider. It could present indisputable proofsregarding these theories and principles of modern physics however,it can also disprove these principles based on the experimentalresults.
TheLarge Hadron Collider
Byits name, the Large Hadron Collider is basically a huge-sizedcollider of hadrons. A hadron, which comes from the Greek word‘adros’ denoting ‘bulky’, are particles made up of quarks andis considered the family where protons and neutrons belong.Fundamentally, it is a collider because it accelerates hadrons(protons or ions) which form two beams that are travelling fromopposite directions that collide are four points which comprises theintersection of the two ring components of the instrument (CERN,2009)
TheLHC weighs 38,000 tons and runs inside a circular tunnel with acircumference of approximately 27 km (17 mi) which is 175 metersbelow the Franco-Swiss border at Geneva, Switzerland, where CERN’slaboratory is based (STFC, n.d. CERN, 2009). It was built incollaboration with tens of thousands of participating scientist andengineers from over a hundred countries, universities andlaboratories.
Thelarge size of the LHC is associated to the maximum energy that can beobtained. The collider is a function of the machine’s radius andthe strength of the dipole magnetic fields which maintains thecircular orbit of the particles. The LHC makes use of theradio-frequency cavities and the most powerful dipoles existing. Theessential elements of the machine such as tunnel size, cavities andmagnets and other factors affecting the LHC are some of theconstraints that must be controlled to maintain the design energy of7 TeV per beam of a proton. A collider is advantageous over otheraccelerators since counter-circulating beams collide in action. Whentwo beams collide, the sum of the energy of these beams representsthe total energy of collision (CERN, 2009 Evans, 2007 US/LHC,2012).
TheLHC usually deals with particles of the same kind which are commonlyprotons or lead ions, representatives of the hadron family. One ofthe limitations of the LHC is that it can only accelerate certaintypes of these particles. Also, the particles much be charged sinceelectromagnetic devices can only have an effect on charged particlesand it does not need to decay. These factors limit the feasibleparticles that can be accelerated to protons, ions and theirantiparticles and electrons. Consequently, circular acceleratorsprefer heavy particles since they have lower energy loss per turnduring synchrotron radiations as compared to lightweight particles.Thus, in order to obtain high energy collisions, massive particlessuch as protons are more effective in the accelerator (CERN, 2009Alison, 2012).
Theenergy concentration is one of the factors that make particlecollision distinct. Each proton beam that enters the LHC has energyof 7 TeV. Thus, collision of 2 protons results to energy of 14 TeV.Theoretically, lead ions have more protons which produce greaterenergy that can reach collision energy of 1150 TeV. Since the energyof collisions varies, it must be noted that the most importantparameters for accelerators are the beam energy and the quantity ofinteresting collisions. Luminosity is a quantity that can be used asa measurement for LHCs. It is mainly dependent on the number ofparticles in a bunch, the quantity of bunches the cross-section ofthe beam and the frequency of complete turns in the collider. For amore effective process, it can be maximize through squeezing ofparticles into the smallest space in the interaction section of theLHC. The circulation of the particles is manipulated viaelectromagnetic devices. Different electromagnetic devices areemployed in the LHC which are as follows: (1) dipole magnets whichmaintain the circular orbiting of the particles, (2) quadrupolemagnets which focus the beam and (3) accelerator cavities which areelectromagnetic resonators that keep the energy constant for theparticles through compensation of energy losses (CERN, 2009 Alison,2012 Evans, 2007 Rossi, 2000).
Furthermore,the collider is only one of the significant parts of the LHC project.The detectors and the GRID are the other two important parts of LHCproject. The detectors can be found at different points around theLHC tunnel which is housed in 4 different large chambers. The GRID isa large comprehensive network of computers with built-in softwaresnecessary for data processing from the recorded figures of thedetectors (STFC, n.d.).
TheLHC is an important machine that allows scientist to delve deeperfurther back in time and into the undiscovered parts of matter. Theresults from the experiments based on the LHC are hard to predictsince the experimental ideas are at the limits of our understanding.LHC projects aims to uncover new facts about the origins of ouruniverse and matter.
CERN(2009) pointed out that the “Standard Model of particles andforces” can summarize our current knowledge regarding particlephysics. This model has been established through differentexperiments and has been proven to be successful in discovery of newparticles that had been in existence before. However, there areissues that are left unexplained that are interconnected in thismodel (Ekeren, 2013). One of these unexplained issues is the originof mass. It has not been explained yet why there are particles thatare heavy and why some have no mass at all. This was attributed tothe Higgs Mechanism. The Higgs mechanism points out the existence ofthe ‘Higgs field’ which fills the whole space and the acquisitionof mass by particles is through interaction within this fields.Theoretically, those particles that intensely interact within thefield are heavy and those that have weak interactions are light. Aparticle known as the Higgs Boson can be associated in determiningthe existence of the Higgs field and can be detected using the LHC(Ekeren, 2013 CERN, 2009). Another unexplained issue is there is nounified description regarding the fundamental forces since it is hardto theorize about the gravity involving other forces. TheSupersymmetry Theory explains the existence of other inactivepartners of the standard particles that currently exist. This theorycan help in the unification of the fundamental particles and forces.The cosmological observations have also shown that all the matterthat are visible accounts only for 4% of the universe. Physicistssearch for particles or occurrences that are responsible forexistence of dark energy (73%) and dark matter (23%). Dark matter isformed from neutral supersymmetric particles which are stillundiscovered. The existence of dark matter was first hinted during1933 when it was found out that there is more material in theuniverse that are hide in plain sight. Its gravitational effect aidsin the faster spinning of galaxies. Dark energy is presumed to makeup approximately 70% of the universe and is related to the vacuum inthe space. It is believed that dark matter is homogeneouslydistributed in the universe. Due to this even distribution, itsgravitational effects in the universe are global. It also tends toaccelerate the expansion of the universe caused by repulsive forces.Dark energy’s existence has been confirmed due to the experimentsusing the Hubble law. The mystery of antimatter is also an unansweredquestion. Theoretically, matter and antimatter is thought to beproduced in equal amounts during the Big Bang. However, the onlyobservable part of the universe is the matter. The LHC can helpprovide answer on how this happened. Amount of antimatter is bound bylimits such as the diffuse cosmic gamma-rays and inhomogeneities ofthe cosmic microwave background (CMB). The cosmic gamma rays havebeen produced from the annihilations during the big band. The amountof the annihilation cross sections, cosmic redshifts and the distancecan lead to prediction of existence of gamma rays. For theinhomegeneities in the CMB, the antimatter leads to heating up of theboundaries and is showed in the CMB through density fluctuations. Asaddition to the existing studies regarding proton-proton collisions,the LHC also covers heavy ion collisions which can lead to thediscovery of the state of matter that is believed to have beenexistence in the early universe – the quark-gluon plasma. Thisplasma is formed through heavy ion collisions at high energies whichfurther forms a bolide of hot dense matter (CERN, 2009 US/LHC,2012).
Intracking and charactering the collision of different particles,detectors are used for monitoring and observing more information fromthe process. The charge and the momentum can be detected using theanalysis of the collision from the detectors. The principle ofparticle detectors is very simple although the practice can be morecomplex. Thereare seven constructed detectors made in the LHC and two of them areparticle detectors for general purpose: ATLAS experiment and CompactMuon Solenoid (CMS) (CERN, 2009).
ATLASis a large particle detector used for general purpose of detectingparticles. The main features of the ATLAS which is a large circularmagnet system to search for the super-symmetry (SUSY), the Higgsboson, and for other extra dimensions which covers large area ofpossible physics. The size of ATLAS can be described to be like a5-storey building and it is the largest collision detector to beconstructed in terms of the volume used. It consists of longsuperconducting coils of magnets which form a cylinder and thedetector is placed at the center for the beam pipe to collect. Theother general-purpose collision detector is the CMS. It has the samegoals as the ATLAS but it was built with different technical design.The magnets were used to form superconducting solenoids. It wasconstructed to generate 4 T magnetic fields which are 100,000 timesmore powerful than the earth’s magnetic field (CERN, 2009 Bethke,2005).
Othercollision detectors have specialized purpose and was built withdifferent technical solutions. A large ion collider experiment(ALICE) is specialized in the analysis of the collision of Lead ions.The purpose of ALICE is to study the different properties ofquark-gluon plasma. It is a state of matter accompanied by hightemperature and densities which the quarks and the gluon no longertrapped inside the hadron. It is believed that this state of matteronly existed just after the Big Bang and the particles such asneutron and protons are just forming (Harder, 2009, Ekeren, 2013CERN, 2009).
TheLarge Hadron Collider beauty experiment (LHCb) is also a specializedpurpose collision detector. It aims to study the properties of theparticles with b quarks or simple called the B-particles. Itinteractions have a slight similarities with the interaction ofmatter and antimatter. The study aims to understand the idea why theuniverse is consisting only of the matter that we can observe. Othercollision detectors have also specialized purpose such as the LHCf,TOTEM, and MoEDAL (CERN, 2009 Alison, 2012 Ekeren, 2013).
LHCand its impact to the world of particle physics
LHChas made a lot of impact to the world of science. It gives as abetter and gradual understanding of how the universe came. It alsooffers training to engineers and scientists involve in the projectsand researches (STFC, n.d.). Many milestones have been brought by theLHC. A year after its inauguration in 2008, the LHC was named as thelargest and highest-energy particle accelerator which has achieve1.18 TeV per beam. On December 2009, the ALICE detector hasfacilitated 284 collisions which is the first known physics resultfrom the LHC. By early February 2010, the first proton-protoncollisions were conducted by the CMS detector team. In April 2011,the LHC achieve a luminosity peak of 4.67·1032 cm−2s−1,another record set being the highest-luminosity for a hadronaccelerator. By May 2011, the quark-gluon plasma was recreated. Thebiggest discovery yet of the LHC is the new boson that is in linewith what is theorized in the Higgs boson and has been proven as theHiggs boson itself. It was detected through the CMS and ATLASdetectors which have shown intensity peaks of 124-125 GeV (Bethke,2005 Ekeren, 2013 Alison, 2012).
Sinceone of the outcomes of the particle physics experimentation on theLHC is the diminishing returns, considerations for upgrading of thedevices involving luminosity, energy and the detectors have beenproposed. These discoveries lead to the proposal of larger hadroncolliders such as the Super Large Hadron Collider or the Very LargeHadron Collider. By 2013-2015, it has been planned to put up anupgrade on the LHC which is the High Luminosity LHC proposal.Continuous research collaborations by scientists and engineers aredone in relation to the LHC Accelerator Research Program (LARP) inorder for them to achieve the goals of answering all unexplainedissues regarding Particle Physics.
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