Big Bang at the Large Hadron Collider

1
Big Bang at the Large Hadron Collider
Its Big, its Large, its heavy and its clever.
How Glasgow physicists helped build the machine
that launches today..

• University of Glasgow
• Open Day
• September 10th 2008
• Tony Doyle

2
Thank You!
For attending today There are many other things
you could be doing on Wednesday September 10th at
11am
3
Today! Worldwide News
4
Heritage - Past

• The first electron synchrotron in Europe was
  constructed in this building in the 1950s
• E 300 MeV

5
Heritage - Present

• The scale of the Large Hadron Collider that
  switches on today is larger
• 27 km in circumference
• E77 TeV

6
Outline

• Ingredients
• Motivation
• Commissioning
• Collider
• Detectors
• ATLAS
• LHCb
• Grid
• Outlook

7
Universe Particles LHC?
8
Physics at the LHC corresponds to conditions
around here
9
The Standard Model
10
LHC Motivation Higgs Production in pp Collisions
q
Z0
q1
W
W
q2
H
p
p
Z0
q
MH 1 TeV EW 0.5 TeV E1 1 TeV E2 gt 1 TeV
Parton luminosities Ecm?(4x1x2.EpEp)
? Proton Proton Collider with Ep 7 TeV
11
LHC Switches On
12
LHC Commissioning
Cool down status 7/9/08

• The LHC has cooled down..
• Today First particles injected, followed by
  commissioning with beams
• Oct/Nov First detector collisions at 5510 TeV

13
The ATLAS Detector
ATLAS large international collaboration to find
the Higgs (and much more) in the range 0.1TeV lt
mH lt 1TeV
The ATLAS experiment is 26m long, stands 20m high
and weighs 7000 tonnes SCT alone has 6.2 million
read-out channels
14
A question of scale
15
Where Theory Meets Experiment 1964 to 2005
16
The Higgs Mechanism
Higgs potential V(?) -?2?? ?(??)2
(?gt0) ?exp(i?a(x) Ta) ?0 . (?0
H(x)) mH ?? 2 (a free parameter)
Theory vacuum potential
The ultimate green field site
Energy
Ready to interact
17
Where Theory Meets Experiment 14th April 2008
18
Dark Matter?
Astronomers say that most of the matter in
the Universe is invisible Dark Matter
Supersymmetric particles ?
We shall look for them with the LHC
19
Dark Matter at the LHC?

• Characteristic signature for Dark Matter
  production at ATLAS
• Missing Transverse Energy (MET)
• Valid for any DM candidate
• (not just SUSY)
• Observation of MET signal necessary but not
  sufficient to prove DM signal (DM particle could
  decay outside detector)

Combine LHC and Astroparticle physics data in
order to prove that the neutralino hopefully
observed at LHC would be the DM particle
20
Search for Extra Dimensions
Theories which try to explain why gravity is so
much weaker than the other forces Gravity may
propagate in 4n dimensions, but we could
see strong effects only at very small distances,
reachable in pp LHC collisions
21
Search for Extra Dimensions
If theories with Extra Dimensions are true,
microscopic black holes could be abundantly
produced and observed at the LHC
They decay immediately through Hawking radiation
Simulation of a black hole event with MBH 8
TeV in ATLAS
22
Progress on ATLAS
23
Today the cavern is filled (with the ATLAS
detector) and it is has become impossible to take
a real picture
24
Progress on LHCb
25
LHC Experiment Commissioning
June 15, 2008 ALICE saw first hits in silicon
pixel detector During clockwise
beam Synchronisation test

• Early 2008
• Cosmic rays measured
• in ATLAS experiment

• Sunday 24th August
• First tracks from LHC beam in the LHCb detector

• Stop Press 0919
• First beam-gas event in the ATLAS experiment
• Event number 40050 Event run 87765

26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
The Grid

• The Grid enables us to analyse all the data that
  comes from the LHC
• Petabytes
• 100,000 CPUs

• Distributed around the world
• Now used in many other areas

30
The Grid
Archeology Astronomy Astrophysics Civil
Protection Comp. Chemistry Earth
Sciences Finance Fusion Geophysics High Energy
Physics Life Sciences Multimedia Material
Sciences
gt250 sites 48 countries gt50,000 CPUs gt20
PetaBytes gt10,000 users gt150 VOs gt150,000 jobs/day
31
Why (particularly) the LHC?
2. Complexity

• Rare Phenomena
• - Huge Background

All interactions
10 orders of magnitude
The HIGGS
When you are face to face with a difficulty you
are up against a discovery Lord Kelvin
32
The Challenges I Real-Time Event Selection
10 orders of magnitude
Time
Real-Time
In-Time
33
The Challenges II Real-Time Complexity

• Many events
• 109 events/experiment/year
• gt1 MB/event raw data
• several passes required
• Worldwide Grid computing requirement (2008)
• 300 TeraIPS
• (100,000 of todays fastest processors connected
  via a Grid)

Detectors
16 Million
40 MHz
channels
3
Gigacell
buffers
COLLISION RATE
Charge
Time
Pattern
100 kHz
LEVEL
-
1 TRIGGER
Energy
Tracks
1 MegaByte
EVENT DATA
1 Terabit/s
200 GigaByte
BUFFERS
(50000 DATA CHANNELS)
500 Readout memories
EVENT BUILDER
500 Gigabit/s
Networks
20
TeraIPS
EVENT FILTER
Gigabit/s
PetaByte
Grid Computing Service
SERVICE LAN
ARCHIVE
300
TeraIPS

• Understand/interpret data via numerically
  intensive simulations
• e.g. ATLAS Monte Carlo (gg H
  bb) 60 sec/3.5 MB event on 3 GHz linux CPU

34
Focus on LHC Physics

• LHC Start-Up

• Early Physics

35
Voyage of Discovery
The decade to come will be exciting for
fundamental physics and will shape our
understanding of Nature
36
And finally

• We are privileged to stand on the shoulders of
  giants and work in particle physics today
• The invention of the LHC will enable future
  physicists, including perhaps some of you, to
  rewrite the physics textbooks
• The first step is a degree in physics astronomy

• A degree will enable you to
• understand how our Universe works
• find better places to work within it

37
First year physics astronomy
Physics includes lasers, quantum phenomena,
dynamics and relativity Astronomy includes
stellar physics and cosmology
at work in the lab
Kelvin lecture theatre
The University Observatory
The Departmental common room
38
Thanks to the many particle physicists whove
helped to make this talk possible. Esp. Peter
Jenni for useful slides. We get by with a little
help from our friends