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Mass Mystery, LHC andInformation Technology

Pawan K. Diwan

UIET, KUK

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Weight & Mass

W = mg

where m is the mass of the object

g is the gravitational field strength.

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Atoms

proton

neutron

electron

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Matter Particles: Quarks and Leptons

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Elementary Particles: Matter particles and mediators

Matter particles are fermions and mediators arebosons.

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Masses (GeV/c2) of elementary particles

t

b

cs

ude

e

Mass

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The Standard Model

H= the missing ingredient: theHiggs Boson

Very successful to describe all observed phenomena in thesubatomic world so far.

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Higgs Mechanism

According to Higgs, at the time of Big-Bang,all the elementary particles have zero mass.

With the time, the elementary particlesinteract with the Higgs field (field uniformlydistributed in space) and as a result gain the

masses.

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The Higgs field would form a uniform background within the

universe. Each particle would interact with the Higgs boson to a

different degree.

Imagine a room full ofpolitical activists

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The Prime Minister walks in

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The more strongly a particle interacted with the Higgs, themore mass it would gain and the more inertia it woulddisplay

He is surrounded by acluster of people

Analogous togeneration of Mass

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Why different particles have different

massesMass gain by the particles depends upon the number

of interactions with the Higgs field.

Larger the interaction with the field, larger is the gainof masses.

The particles passes through the field withoutinteraction, then the particle will not gain any mass.

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Large Hadron Collider

Length of theaccelerator is 27km in the form of

circle and ispositioned in atunnel, whichcrosses the borderof two countries.

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Hunt for the Higgs bosons (Planning)

To generate proton and anti-proton beam of energy 7

TeV/particle (1TeV = 1012eV) in two different ultra

high vacuum beam pipes These particles to move in opposite directions

Finally to collide with each other through head on

collision

So, through each proton and anti-proton collision,

total energy becomes 14 TeV.

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The collision of proton and anti-proton does not

mean only one proton and one anti-proton interactswith each other.

In actual practice, trillions of particles are moving

and 40 millions collisions will occur per second.

To observe these collisions and finally to detect

Higgs bosons, ATLAS (AToroidal LHC ApparatuS)

and CMS (Compact Muon Solenoid) big detectorsare installed in LHC experiment.

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LHC Data every year

40 million collisions per second

After filtering, 100 collisions of interest per second

> 1 Megabyte of data digitised per collision

recording rate > 1 Gigabyte / sec

1011 collisions recorded each year

stored data > 15 Petabytes / year

(1PB = 109MB)

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LHC Data every year

LHC data correspond to about

20 million CDs each year

Where will theexperiments store all

of these data?

Balloon

(30 Km)

CD stack with

1 year LHC data!

(~ 20 Km)

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LHC Data Processing LHC data analysisrequires a

computing powerequivalent to

~ 100,000 of today'sfastest PCprocessors

Where willthe

experimentsfind

such acomputing

power?

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Computing power available at CERN

More than 35000 CPUs

in about 6000 boxes (Linux)

14 Petabytes on 14000 drives

(NAS Disk storage)

34 Petabytes on 45000 tape slotswith 170 high speed drives

Nowhere near enough!

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The World Wide Web

The "Web" as it is affectionately called, was originally

conceived and developed for the large high-energy physics

collaborations which have a demand for instantaneous

information sharing between physicists working in different

universities and institutes all over the world. Now it has

millions of academic and commercial users.

1990:Tim Berners-Lee, a CERN computer

scientist invented the World Wide Web.

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Computing for LHC

Problem: Even with Computer Centre upgrade, CERN can provide

only a fraction of the necessary resources

Solution:Computing centers, which were isolated in the past, will be

connected,uniting the computing resources of particle physicists

worldwide

Users of CERN

Europe:

267 ins titut es

4603 us ers

Out of Europe:

208 ins titut es

1632 us ers

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Yeeeeaaahhhh!!!!!Now I can know theorigin of mass..

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