Ivo van Vulpen

1
Top quarks and physics at 100 zeptometer
Ivo van Vulpen
2
Particle physics
Study nature at distance scales lt 10-15 m
10-15 m
atom nucleus

A quantum theory describes all measurements down
to 10-18 m
2/10
3
Particles
Forces
1) Electromagnetism2) Weak nuclear force3)
Strong nuclear force
Quarks
Leptons
3/10
4
The big questions

• What is dark matter made of ?
• Why is gravity so different ?
• What explains the required (extreme) tuning of
  parameters ?

4/10
5

• Model is an approximation of a more
  fundamental one.
• ? Model breaks down below 10-19 m
• New phenomena will appear at distances 10-19 m

2006
5/10
6
The LHC collider proton-microscope
- proton-proton- high energy / intensity- start
summer 2007
ATLAS detector
LHC tunnel
6/10
7
What will LHC events look like?

• Problem new distance scale and new detector
• Before claiming you have observed something
  new you need to understand what old
  physics looks like

Most complex old physics top quark pairs
7/10
8
Why look at top quarks ?
Old physics, but not known physics!

• The top quark

Expected top quark mass distribution (end of 2007)
- Discovered in 1994 (few 100 events) -
Mass 175 x proton mass
Number of events

• My current research

At LHC top quarks copiouslyproduced (high energy)
- We can identify top quarks in early LHC
data
Mass of top quark (GeV)
8/10
9
100 zeptometer frontier discover new physics

• What do new phenomena look like ?
• - Depends strongly on theoretical model -
  Many models include a signature that looks
  a lot like top quarks, but not quite
• My strategy Focus on this single signature
  rather than on a single theoretical model
• - Single source of known physics that can
  mimic this is top quark production (which
  we understand !)

9/10
10
Why am I doing this ?
Detector commissioning
Data-Analysis(search measurement)
PhD thesis
CERN fellow
Research group
Top quark physics in ATLAS
VIDI !
NIKHEF post-doc
1) Leptons Identification and Trigger2) Quarks
Jet energy scale and top cross section3)
Kinematic fit4) Top characteristics and Model
interpretation
10/10
11
Time-line
Phase 1 Prepare and studyfirst LHC collisions
Phase 2 Re-discover top quark
Phase 3 First to observe and study new
phenomena
Plan of work
Discover super-symmetry ?Discover extra
dimensions ?