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Particle Physics An Overview Prof. Muhammad Saeed

Particle Physics An Overview Prof. Muhammad Saeed

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Page 1: Particle Physics An Overview Prof. Muhammad Saeed

Particle PhysicsAn Overview

Prof. Muhammad Saeed

Page 2: Particle Physics An Overview Prof. Muhammad Saeed

History: Yin Yang air, fire, water and earth Thales of Miletus (624-546 B.C.); water Anaximander (611-547 BC); mass, eternity: produces

opposites like heat and cold Pythagoras (580-500 B.C.); numbers, ratios,

communication with God Anaxagoras (500-428 B.C.); apparent, substance Empedocles (490-430 B.C.); air, fire water and earth Democritus (460-370 B.C.); atoms, void Plato (429-347 B.C.); air, fire, water and earth

(octahedron, tetrahedron, icosahedron and hexahedron) Aristotle (384-322 B.C.); continuity, motion, no void,

qualities combine to form elements Epicurus (341-270 B.C.); atoms, indestructibility Archimedes (287-212 B.C.); Mathematical Physics

300 B.C. to 150 A.D. Antique Mathematical Physics Jabir ibn Hayyan (721-815 A.D.) Al Hazen (965-1039 A.D)

2Particle Physics

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Particle Physics 3

History: Timeline

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Particle Physics 4

Standard Model

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Standard Model

Matter:Hadrons (quarks and anti quarks)

Baryons(made of three quarks) Mesons (made of one quark & one antiquark)

Leptons (fundamental particles)

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Flavors of quarks:1. up 2. down3. charm 4. strange5. top 6. bottom

Color Charges on quarks:1) Red 2) Green 3) Blue

Standard Model

Murray Gell-Mann proposed the quark model in 1964 (containing originally only the u, d, and s quarks).

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Quarks & Gluons:

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Pion

In the image PION is composed of two quarks up (u)and anti down(đ ) with color charges blue and antiblue. The gluon carries antiblue and red charges just leaves antiblue u quark .Resultant color charges on both quarks= ?

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FORCE PARTICLE/QUANTUM

RELATIVE STRENGTH

MASS (GeV)

RANGE(meters)

Strong nuclear gluon 1 0.14 (?) 10-15 Electromagnetic photon 7 X 10-3 none infinite

Weak nuclear W+,W- & Z bosons 10-5 80-90 10-17

Gravitation gravitron (tentative) 6 X 10-39 none infinite

Bosons

And Higgs Boson mass nearly 190 times of a proton

Standard Model

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Particle Physics 11

Big Bang Timeline:

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Particle Physics 12

Methods of Particle Physics1. Mathematical

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The Feynman diagram of the term

Feynman Diagrams:

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Symmetry:a. Discrete Symmetry

1. Parity P is the transformation for x -x P(x, t) = (x, t)

2. Charge Conjugation C: changing particle to antiparticle

3. Time reversal Tb.Continuous Symmetry

1. Rotation 2. Translation

c.SupersymmetrySuperparticles: squarks, gluinos,

charginos, neutralinos, and sleptons

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QCD (Quantum Chromodynamics)

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Methods of Particle Physics2. Experimental

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Accelerators

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Linear Accelerators:The design of a linear particle accelerator (also called a linac) depends on the type of particle that is being accelerated: electron, proton or ion. They range in size from a cathode ray tube to the 3,4 km long Stanford Linear Accelerator Center (SLAC) in California at 426 acres. SLAC started in 1996. , Lepton and charm quark discovered. 3 Nobel prizes on the discoveries(Physics). Nearly 50 Gev achieved.

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Circular Accelerators:

Aerial photo of the Tevatron at Fermilab. The main accelerator is the ring above; the one below (about one-third the diameter, despite appearances) is for preliminary acceleration, beam cooling and storage, etc. It was completed in 1983.In 1995, the high-energy collisions of the Tevatron led to the discovery of the top quark.The Tevatron accelerates and collides protons and antiprotons in a 6.28 km long underground ring to energies of up to 1 Tev. Still in race to find out Higg’s particle. May shut down in 2011.

Big Old Lady

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LHC

The Large Hadron Collider

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LHC (Large Hadron Collider)

The LHC will accelerate two beams of particles of the same kind, either protons or lead ions, which are hadrons, together in head-on collisions at energy levels higher than ever achieved before. The collider is housed inside the already existing circular tunnel that is almost 27 km in circumference and about 100 metres underground. The tunnel starts near CERN (Meyrin), goes close to the Jura mountains, continues underneath French countryside, comes round near Geneva airport (Switzerland) and then back to CERN.

Protons accelerated by different machines are finally transferred to the LHC (both in a clockwise and anticlockwise direction, the filling time is 4’20’’ per LHC ring) where they are accelerated for 20 minutes to their nominal 7 TeV.

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Components of LHC

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The ATLAS detector (A Toroidal LHC ApparatuS) is the world’s largest general-purpose particle detector, measuring 46 meters long, 25 metres high and 25 meters wide; it weighs 7000 tons and consists of 100 million sensors that measure particles produced in proton-proton collisions in CERN’s Large Hadron Collider. The first piece of ATLAS was installed in 2003 and since then many detector elements have journeyed down the 100 metre shaft into the ATLAS underground cavern. This last piece (lowered in March 2008) completed this gigantic puzzle.

A T L A S

ATLAS is a worldwide collaboration comprising over 2100 scientists and engineers from 167 institutions in 37 countries and

ATLAS may also provide the answer for the mysterious dark matter and energy of the Universe and look for extra dimensions of spacetime. This detector is designed to be capable of discovering new particles and new phenomena expected from extensions of the Standard Model such as supersymmetry, and to be able to observe the Higgs boson.

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C M S

The CMS collaboration comprises 2300 scientists from 159 scientific institutes in 37 countries.

The main volume of the CMS detector is a multilayered cylinder, some 21 m long and 16 m in diameter, weighing more than 13,000 tons. The innermost layer is a silicon-based particle tracker, surrounded by a scintillating crystal electromagnetic calorimeter which is itself surrounded with a sampling calorimeter for hadrons measuring particle energies. They fit inside a central superconducting solenoid magnet (3,8 Tesla) , 13 m feet long and 6 m in diameter, that measures the momenta of charged particles. Outside the magnet are the large muon detectors, which are inside the return yoke of the magnet.

CMS (Compact Muon Solenoid) is designed to explore the physics of the Terascale, the energy region where physicists believe they will find answers to the central questions at the heart of 21st-century particle physics: Are there undiscovered principles of nature? Is Higgs mechanism responsible for visible mass of the universe? How can we solve the mystery of dark energy? Are there extra dimensions of space? How did the universe come to be?

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A L I C E ALICE (A Large Ion Collider Experiment), will study relativistic heavy ion interactions.The aim of the ALICE collaboration is to study the physics of strongly interacting matter at extreme densities where the formation of a new phase of matter, the quark-gluon plasma, is expected. In some way ALICE will be reproducing the Big Bang.

The detector consists of two main components: the central part composed of detectors dedicated to the study of hadronic signals and electrons, and the forward muon spectrometer dedicated to the study of quarkonia behaviour in dense matter. The central part is embedded in a large solenoid magnet with a weak field (full current of 6000 amps and magnetic field of 670 millitesla).

TPC is the principal component of ALICE and it's a time projection chamber. A cylindrical device filled with gas and incorporating uniform electric and magnetic fields, a TPC is ideal for separating, tracking, and identifying thousands of charged particles in a dense environment — such as the thousands of particles produced in an energetic heavy-nuclei collision. It is the main detector in many high-energy physics experiments.

Alice collaboration: 29 countries, 86 institutes, 1000 members.

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LHCb The LHCb (Large Hadron Collider beauty experiment) is a 21m long, 10m high and 13m wide detector and it’s designed to study CP violation and other rare phenomena in decays of hadrons with heavy flavours, in particular B’s mesons.

In order to explain the dominance of matter over antimatter observed in our universe, which could be regarded as the largest CP violation effect ever seen. The LHCb experiment will improve significantly results from earlier experiments both quantitatively and qualitatively, by exploiting the large number of different kinds of b hadrons produced at LHC. B mesons are most likely to emerge from collisions close to the beam direction, so the LHCb detector is designed to catch low-angle particles

565 scientists from 47 universities and laboratories from 15 countries are involved in the design and construction of LHCb, with support from many hundreds of technicians and engineers.

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T O T E MThe TOTEM (Total Cross Section, Elastic Scattering and Diffraction Dissociation) experiment measures the total pp cross-section and study elastic and diffractive scattering at the LHC.

Modest in size, TOTEM is installed near the point where protons collide in the center of the CMS detector. It uses silicon sensors installed in the LHC tunnel approximately 200 meters away from CMS.

The experiment measures particles scattering at very small angles from the LHC's proton-proton collisions, allowing scientists to study physical processes that can’t be studied by the other LHC experiments, such as how the shape and size of a proton varies with energy. TOTEM scientists will study inelastic proton-proton collisions in which one proton survives and the other disintegrates and produces "debris" that continues traveling forward. They will also measure elastic collisions in which both protons survive and only slightly deflect each other.

The TOTEM experiment uses three detector types: Roman Pots with microstrip silicon detectors used to detect protons; and Cathode Strip Chambers and GEM Detectors that will measure the jets of forward-going particles that emerge from collisions when the protons break apart.

The TOTEM collaboration comprises some 80 physicists from 11 universities and laboratories in eight countries.

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LHCfLHCf (LHC forward) experiment is placed on either side of the ATLAS experiment about 140 meters from the interaction point at a zero degree collision angle. Their two detectors, made of tungsten plates and plastic scintillators, can accurately measure the number and energy of neutral pions and other particles produced in the forward direction in ATLAS collisions.

The aim of LHCf experiment is the study at the LHC accelerator of the neutral-particle production cross sections in the very forward region of proton-proton and nucleus-nucleus interactions. Neutral pions, gammas and neutrons production will be investigated during the initial phase of the LHC running, at low luminosity (below 1030cm-2s-1). This study will give important information for understanding the development of atmospheric showers induced by very high energy cosmic rays hitting the Earth atmosphere.

These measurements, together with the measurement of the total inelastic cross-section (TOTEM), are of paramount importance for our understanding of Ultra High Energy Cosmic Rays atmospheric shower development.

LHCf is the smallest one of the six official LHC experiments, and it has an equally small collaboration of just 22 people from 10 institutes in 4 countries.

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MedicineParticle accelerators and detectors first developed for particle physics are now used by every major medical center in the nation to treat and diagnose millions of patients.

Homeland Security From scanning cargo in ports to monitoring nuclear waste, the same advanced detector technology that physicists use to analyze particles also better protects the nation.

Industry Particle physicists rely on industry to produce and advance the millions of components that experiments require, putting companies on a fast-track towards new products and life-changing technologies.

Sciences Particle physicists need cutting-edge tools; many of these benefit other areas of science.

Benefits of Particle Physics

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Computing To record and analyze the unprecedented volumes of data generated in particle collisions, particle physicists develop cutting-edge computing technology, making key contributions to solutions incomputer science.

Workforce Development The majority of students who gain their PhDs in particle physics go on to work for high-tech industry, financial institutions and information technology businesses.

A Growing List The science and technology of particle physics has contributed to many other areas benefitting the nation's well-being. Simulation of cancer treatments, reliability testing of nuclear weapons, curing of epoxies and plastics, improved sound quality in archival recordings are just a few examples on a growing list of practical applications.

Benefits of Particle Physics

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GeneralEach generation of particle accelerators and detectors builds on the previous one, raising the potential for discovery and pushing the level of technology ever higher. The bold and innovative ideas and technologies of particle physics have entered the mainstream of society to transform the way we live. Some applications of particle physics—the superconducting wire and cable at the heart of magnetic resonance imaging magnets, the World Wide Web—are well known. Yet particle physics has a myriad of lesser-known impacts. Food sterilization, nuclear waste transmutation, and scanning of shipping containers are by-products of physics research. Advances in physics continue to revolutionize our treatment of cancer and other debilitating diseases. Theoretical models developed by physicists are applied to a vast range of scientific disciplines as well as commerce. As time moves forward and understanding grows, so too will the list of practical applications.

A Growing List The science and technology of particle physics has contributed to many other areas benefitting the nation's well-being. Simulation of cancer treatments, reliability testing of nuclear weapons, curing of epoxies and plastics, improved sound quality in archival recordings are just a few examples on a growing list of practical applications.

Benefits of Particle Physics

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