The Large Hadron Collider

Prof.Dr.Issam RashedWalaa salem adli mosleh

International organization whose purpose is operate the world's largest particle physics laboratory to study the basic constituents of matter - the fundamental particles and the fundamental structure of the universe

At CERN there is the European Organization for Nuclear Research , physicists and engineers.

What is the universe made of? How did it start? Why is gravity so much weaker than the other fundamental forces? Physicists at CERN are seeking answers, by using one of the world's

most powerful particle accelerator, which is???

European Council for Nuclear Research

CERN

The Large Hadron Collider (LHC) Is the world’s largest and most powerful particle accelerator, from its name is collider and it has dedicators

It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008

located on the France/Switzerland border and remains the latest addition to CERN’s accelerator complex.

at a depth of 100 m below a number of accelerators are joined together in sequence where the particle beam travels from one end to the other

Their job is to speed up and increase the energy of a beam of particles by generating electric fields that accelerate the particles, and magnetic fields that steer and focus them.

a circular accelerator

a linear accelerator

An accelerator comes either in the form of a ring (a circular accelerator)

Or in a straight line (a linear accelerator)PARTICLES AND SOURCEThe Large Hadron Collider (LHC) accelerates and collides

protons, and also heavy ions like lead ,the type of particle used depends on the aim of the experiment

In the first part of the accelerator: an electric field strips hydrogen nuclei of their electrons. Electric fields along the accelerator switch from positive to

negative at a given frequency, pulling charged particles forwards along the accelerator.

CERN engineers control the frequency of the change to ensure the particles accelerate not in a continuous stream, but in closely spaced “bunches”.

A radiofrequency (RF) cavity Is a metallic chamber that contains an electromagnetic field. Its primary

purpose is to accelerate charged particles.

Radiofrequency (RF) cavities –spaced at intervals along the accelerator

Each time a beam passes the electric field in an RF cavity, some of the energy from the radio waves is transferred to the particles, nudging them forwards

It’s important that the particles do not collide with gas molecules on their journey through the accelerator, so the beam is contained in an ultrahigh vacuum inside a metal pipe – the beam pipe.

a linear accelerator Linear accelerator 2 (LINAC 2) which use in the Large Hadron Collider the first accelerator in the chain, accelerates the protons to the energy of 50 MeV Linear accelerator use radiofrequency cavities

Radiofrequency cavities along the LHC accelerate particles and keep them in controlled bunches (Image: CERN)

the trillions of particles in the beam revolve around the largest ring (LHC)27-kilometre 11,245 times per second and around three synchrotrons

PSB Proton Synchrotron Booster PS Proton Synchrotron SPS Super Proton Synchrotron

Inside the accelerator, two high-energy particle beams travel at close to the speed of light before they are made to collide.

The beams travel in opposite directions in separate beam pipes kept at ultrahigh vacuum.

The protons would each have an energy of 7 TeV [trillion electron-volts], giving a total collision energy of 14 TeV

CIRCULAR ACCELERATORS

They are guided around the accelerator ring by a strong magnetic field comes from superconducting magnets

All of the magnets on the LHC are electromagnets – magnets.

The magnetic field is produced by the flow of electric current in the coils

Superconducting material efficiently conducting electricity without resistance or loss of energy at very low temperature.

This requires cooling the magnets to 271.3°C (1.9 k)‑ For this reason, much of the accelerator is connected to a

distribution system of helium liquid

The key element

The Large Hadron Collider(LHC) is the largest cryogenic system (Cryogenics is the branch of physics that deals with the

production and effects of very low temperatures) in the world and one of the coldest places on Earth

In particle detectors it is also used to keep heavy gases such as argon or krypton in a liquid state

there is four cylindrical refrigerators called cryomodules – two per beam – which keep the RF cavities working in a superconducting state, without losing energy to electrical resistance

120 tones of helium to keep the magnets at 1.9 K.

Collision & detectors

The LHC accelerates beams of particles ( protons, heavy ions) and brings them into collision inside the four large detectors

ALICE, ATLAS, CMS and LHCB

Particles produced in collisions normally travel in straight lines, but in the presence of a magnetic field their paths become curved. Electromagnets around particle detectors generate magnetic fields to exploit this effect. Physicists can calculate the momentum of a particle – a clue to its identity –

from the curvature of its path: particles with high momentum travel in almost straight lines, whereas those with very low momentum move forward in tight spirals inside the detector

ALICE A Large Ion Collider Experiment

is a heavy-ion detector on the Large Hadron Collider (LHC) ring. It is designed to study the physics of strongly interacting matter at extreme energy densities, where a phase of matter called quark-gluon plasma forms by interaction (ALICE detects quark-gluon plasma)

Protons and neutrons are in turn made of quarks bound together by

other particles called gluons. No quark has ever been observed in isolation

How does quark-gluon plasma form ?Collisions in the LHC generate temperatures more than 100,000 times

hotter than the centre of the Sun ,Under these extreme conditions, protons and neutrons in the nucleus "melt", freeing the quarks from their bonds with the gluons. This is quark-gluon plasma

For a few millionths of a second, shortly after the big bang, the universe was filled with a quark-gluon plasma.

To recreate similar conditions to those of the very early universe, powerful accelerators make head-on collisions between massive (heavy) ions, such as gold or lead nuclei In these heavy-ion collisions the hundreds of protons and neutrons in two nuclei, a few trillion electronvolts are produced by collision, which melt everything into a quark-gluon plasma.

ALICE detects quark-gluon plasma, a state of matter thought to have formed just after the big bang

ATLASA Toroidal LHC Apparatus

is one of two general-purpose detectors at the Large Hadron Collider (LHC).

It investigates a wide range of physics, from the search for the Higgs boson to extra dimensions and particles that could make up dark matter

THE HIGGS BOSONIn order to truly understand what the Higgs boson is, we need to examine one

of the most prominent theories describing the way the cosmos works: the standard model

Standard model theory say everything in the universe is found to be made from a few basic building blocks called fundamental particles, governed by four fundamental forces

the Higgs boson, undiscovered piece of the puzzle predicted by the Standard Model

Physicists announced on July 4, 2012, that, with more than 99 percent certainty, they had found a new elementary particle weighing about 126 times the mass of the proton that was likely the long-sought Higgs boson

At ATLASBeams of particles (protons) collide at the centre of the ATLAS detector

making collision debris in the form of new particles, which fly out from the collision point in all directions.

A huge magnet system(Six different detecting subsystems arranged in layers around the collision) bends the paths of charged particles so that their momentum can be

measured

Higgs boson A newfound particle was discovered by lhc

The Standard Model of elementary particleswith the three generations of matter, gauge bosons in the fourth column and the Higgs boson in the fifth

what is dark matter? • Unlike normal matter, dark matter does not interact with the

electromagnetic force. This means it does not absorb, reflect or emit light

• The matter we know and that makes up all stars and galaxies only accounts for 4% of the content of the universe

• Many theories say the dark matter particles would be light enough to be produced at the LHC

• If they were created at the LHC, they would escape through the detectors unnoticed.

• One idea is that it could contain "supersymmetric particles" – hypothesized particles that are partners to those already known in the Standard Model

• Experiments at the Large Hadron Collider (LHC) may provide more direct clues about dark matter.

In our everyday lives, we experience three spatial dimensions, and a fourth dimension of time.

How could there be more? Now if one dimension were to contract to a size smaller

than an atom, it would be hidden from our view. But if we could look on a small enough scale, that hidden dimension might become visible again.

Imagine a person walking on a tightrope. She can only move backward and forward; but not left and right, nor up and down, so she only sees one dimension. Ants living on a much smaller scale could move around the cable, in what would appear like an extra dimension to the tightrope-walker

extra dimensions

Another way of revealing extra dimensions would be through the production of

MICROSCOPIC BLACK HOLES

What exactly we would detect would depend on the number of extra dimensions, the mass of the black hole, the size of the dimensions and the energy at which the black hole occurs. If micro black holes do appear in the collisions created by the LHC, they would disintegrate rapidly, in around 10-27 seconds

Astronomical black holes are much heavier than anything that could be produced at the LHC

Why is gravity so much weaker than the other fundamental forces?

A small fridge magnet is enough to create an electromagnetic force greater than the gravitational pull exerted by planet Earth.

One possibility is that we don’t feel the full effect of gravity because part of it spreads to extra dimensions.

if extra dimensions exist, they could explain why the universe is expanding faster than expected, and why gravity is weaker than the other forces of nature

How could we test for extra dimensions? One option would be to find evidence of particles that can exist only if extra

dimensions are real.

If gravitons exist, it should be possible to create them at the LHC

We would need to carefully study the properties of the missing object to work out whether it is a graviton escaping to another dimension or something else

This method of searching for missing energy in events is also used to look for dark matter or supersymmetric particles.

The Compact Muon Solenoid (CMS) is a general-purpose detector at the Large Hadron Collider (LHC). It is designed to investigate a wide range of physics, including the search for the Higgs boson, extra dimensions, and particles that could make up dark matter. Although it has the same scientific goals as the ATLAS experiment, it uses different technical solutions and a different magnet-system design.

The CMS detector uses a huge solenoid magnet to bend the paths of particles from collisions in the LHC

CMS COMPACT MUON SOLENOID

experiment specializes in investigating the slight differences between matter and antimatter by studying a type of particle called the "beauty quark", or "b quark".

Instead of surrounding the entire collision point with an enclosed detector as do ATLAS and CMS, the LHCb experiment uses a series of sub-detectors to detect mainly forward particles - those thrown forwards by the collision in one direction.

LHCb LARGE HADRON COLLIDER BEAUTY

There is also other research about • Strangelets• A magnetic monopole• Dark energy• cosmic rays• CLOUD experiment uses a special cloud chamber to study the possible

link between galactic cosmic rays and cloud formation The Proton Synchrotron provides an artificial source of “cosmic rays”

• axions are Hypothetical particles could explain differences between matter and antimatter - and we may find them at the centre of the Sun

• COMPASS investigates how quarks and gluons interact to give the particles we observe

• Gargamelle was a bubble chamber at CERN designed to detect neutrinos

• OSQAR experiment looks for particles that could be a component of dark matter and explain why our

universe is made of matter instead of antimatter

• ATRAP compares hydrogen atoms with their antimatter equivalents - antihydrogen atom an atom of antihydrogen consists of a antiproton and a positron (an antielectron).

• AEGIS uses a beam of antiprotons to measure the value of Earth's gravitational acceleration

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