The Origin of Mass in

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Lecture VII Higgs Properties
Experimental Searches
The Origin of Mass in Particle Physics
60th Compton Lectures Ambreesh Gupta
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The hero is the president of the Astrophysics
Society, the only person ever to win three Nobel
prizes. He stands at night on the beach, legs
planted wide, shaking his fist at the jeweled
blackness of the sky. Anointed by his humanity,
aware of mankinds most powerful achievements, he
shouts at the Universe above the grounds of
crashing waves I have created you. You are the
product of my mind my vision and my invention.
It is I who provide you with reason, with
purpose, with beauty. A fuzzy swirling light
appears in the sky, and a beam of radiance
illuminates our man-on-the-beach. To the solemn
climactic chords of Bach B Minor Mass, or perhaps
the piccolo solo of Stravinskys Rites, the
light in the sky slowly configures itself into
Her face, smiling, but with an expression of
infinite sweet sadness.

- The God Particle
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Readout Channels
Inner Detector 140 Million Channels
Calorimeter 230,000 Channels Muon Detectors
1.2 Million Channels
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Challenges of LHC Computing

• SCALE more than 3 petabytes of raw data per
  year approximately 10 petabytes data total per
  year
• COMPLEXITY an order of magnitude more readout
  channels than earlier experiments
• DISTRIBUTION more than 2000 physicists around
  the globe at least 2/3 of computing resources
  will be outside the host laboratory

10 PB/yearw/reconstruction, Simulation
calibration
200 events/second1.6 MB event (raw)
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GRID To Manage Resources and Data

• Database server replicas deployment for ATLAS DC2
  Grid flavors

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Standard Model Very Well Tested
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Final Picture of Nature?

• Indirect evidence of Higgs
• 115 lt mH lt 200 GeV
• Interaction with Higgs Field
• should give particles their
• masses. . .
• This is an all pervading field
• which has non zero value in
• vacuumoriginated at the
• Big Bang. . .

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We know the particles, We know the
forces Standard Model of is a highly successful
description Is there anything to worry
about? Not from experimental point of
view! Conceptually there are problems foreseen.
BUT, this is Very different situation from turn
of last century, when experiments were seeing
anomalies that needed explanation. When
Coleridge tried to define beauty, he returned to
one deep thought beauty he said, is unity in
variety. Science is nothing else than the search
to discover unity in wild variety of nature, of
more exactly, in the variety of our own
experience.
- The God
Particle
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Grand Unified Theories
The strength of forces depend on the
energy Coupling Constants Strong
1 Electromagnetic
10-2 Weak
10-6 Gravity 10-39
GUT unify Strong and Electroweak forces at 1016
GeV. (GUT Scale) Predicts Proton Should decay
with a lifetime of 1031 years or more. (Lifetime
of Universe 1011 years) Observe 10 ton of water
(1033 protons) No evidence of proton decay (
lifetime gt 1033 years)
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Planck Scale
At the length at which classical ideas of
gravity cease to work Planck length lP
f(h,GN,c) 10-35m Planck Mass MP 1019
GeV (10-5 gm!)
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Hierarchy Problem

• If these scale (GUT and Planck)
• The Higgs will become massive with higher
• energies as it couples to more particles in
  vacuum.
• Possible, but fine tuning of Standard Model
  Parameters
• Hierarchy Problem Why these very different
  scales?

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SuperSymmetry
Unifies matter particles (lepton quarks) with
force carriers (photon, gluon,W/Z)
SUSY solves hierarchy problem e.g., W makes
Higgs mass grow while its superpartner makes it
less cancellation!
SUSY makes all the couplings converge At one
value - unification
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A typical event.

• One track reconstruted in Muon chambers
• Two tracks reconstructed in Inner Detector

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Same event longitudinal view
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Observing SUSY on ATLAS
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Extra Dimensions
What if Planck scale was much lower than 1019
GeV i.e., Gravity became Strong at lower
energies?
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Where are the extra Dimensions?
They could be compactified
 
 
 
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Observing the effect at Collider Detectors
Real and virtual Gravitons would be produced
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Signatures at ATLAS experiment
Monitoring the missing energy in the detector
gives a powerful signature
Present experimental limits say scale of
extra dimension 2 TeV
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Black Hole Production and Decay at ATLAS