Gordon Conference MAD poster

1
Hall A Physics
Welcome to Hall A Jefferson Lab Open
House April 16, 2005
Experiments in Hall A use an electron
beam and a set of spectrometers, which are
like microscopes, to probe the quarks,
the fundamental building blocks of matter.
We learn about the forces between quarks
and about how the quarks arrange
themselves. Basic knowledge about matter
and forces may eventually find its way to
science textbooks and be of practical use.
The Accelerator -- Prepares a High Energy
Electron Beam
Hall A Spectrometers -- the microscopes
International Collaboration of Hall A
Physicists
Accelerator Section
Hall A
Nuclei, which are building blocks of
matter, contain quarks. The quarks are
thought to be fundamental, i.e. indivisible
particles.
High energy electrons needed to resolve
small distances.
How Hall A operates .
Benefits of Physics Research ?

• Education
• Technology Spinoffs
• Long-term Investment

Target region
Scattered Particles are bent in
Spectrometers (this measures their momentum)
and identified in Detector Systems
Electrons strike a target to probe its
matter
(center of hall)
Physics Questions at Jefferson Lab
detectors
Detectors
Shield Hut
Advanced students learn the scientific method
and become professors or scientists in
government, national defense, or industry.
spectrometer
Target
Incident Electron

• What is the universe made of ?
• What is the microscopic structure of
  matter ?
• How are quarks bound together to form
  nuclei ?
• Why are quarks never found alone ?
• Is there anything smaller than quarks ?
• Can we create exotic forms of matter ?

Scattered Particles
Spectrometer
Target
History is rich in examples, e.g. microwaves
and advances in lasers, electronics, and
computing. Technologies from Jefferson Lab
collaborations are finding applications in
medicine, as well as state-of-the-art
electronics.
A detector system
A detector system

• Experiments typically measure
• Energy and spin of incident electron
• Momentum of scattered particles
• Angle of scattered particles

Long-term benefits of basic research, such
as in Hall A, are uncertain and may not
be known for a long time. History has
shown that a fraction of basic science has
enormous long-term impact. For example,
the development of theories of electricity
and magnetism from the 1800s led to
electrical power, radio, television, lasers,
DVDs, etc.

• From this they deduce
• Spatial arrangements of the microscopic
  parts.
• Information to test new theories.

( quarks in the target )