By Heather Rock Woods
The 31st Annual SLAC Summer Institute (SSI) will take on
the very big (the universe) and the very small (sub-atomic particles) from
July 28 to August 8.
SSI’s theme, Cosmic Connections, reflects the growing
links between cosmology, astrophysics and particle physics—exemplified by
the new Kavli Institute for Particle Astrophysics and Cosmology being
built here at the Lab.
"I think it’s a spectacular opportunity for SLAC people. A
lot of big names and talented people are coming here," said SSI Program
Director John Jaros (EA). The other program directors are Charles Prescott
(EA), JoAnne Hewett (Theory) and Tune Kamae (GLAST).
Everyone from advanced graduate students to Nobel
laureates are welcome to participate in SSI, which aims to bring people up
to speed on the basics as well as the latest experimental results, and to
strengthen ties between the various physics fields being discussed.
Afternoons are reserved for discussions and socializing to get
participants actively involved.
"This program is an excellent doorway for people who would
like to go into this new emerging area," said Kamae. "There will be time
to get to know the important people and learn what training you need to go
Amazing discoveries in the last decade point to a universe
far different than previously imagined or depicted in textbooks. "It’s a
radical change of view. It’s getting even more Copernican – we keep
getting smaller and less significant," Jaros said.
Particle physics appears close to discovering answers to
some of the biggest questions in cosmology. Big machines meant to create
and detect tiny particles will shine a light upon the entire universe.
One pressing question is: What makes up the universe? The
building blocks of matter—sub-atomic particles discovered at SLAC and
elsewhere—only account for some three to four percent of the entire
universe’s mass-energy. Nearly 25 percent is attributed to dark matter—all
the matter we can’t see or detect—and the rest is mysterious ‘dark
Particle physics supplies a leading candidate for dark
matter, Supersymmetry, which might be found at the Large Hadron Collider—a
collider under construction at CERN—or at the Next Linear Collider,
currently under design by physicists worldwide. For every known particle,
there is a supersymmetric cousin, similar to the way each matter particle
is related to an antimatter particle. Supersymmetric particles feel the
same forces as their counterparts, but their spins differ by one-half
unit, and their masses are much greater.
Particle physicists "could create what the rest of the
universe is made of for the first time on earth and know it and measure
it," said Jaros.
SLAC is also searching in space for dark matter and dark
energy. SLAC heads an international collaboration of particle physicists
and astrophysicists designing GLAST, a gamma-ray telescope that will be
launched into space in 2006.
Using detector technology similar to SLAC’s, GLAST will
measure the extremely energetic gamma rays generated by massive black
holes, supernovae and colliding galaxies which cannot themselves be
directly measured. Scientists believe these extreme astronomical objects
are some of the major players that determined the evolution of the
universe from a homogeneous soup of matter (like chicken broth) to stars
and galaxies (more like a chunky stew), according to Kamae.
There are other intriguing connections between particle
physics and cosmology. The BABAR
detector is looking for clues about why the universe ended up being
virtually all matter and no antimatter. Recent data from supernovae show
evidence for a ‘dark energy’ that pushes out everything in the universe
faster than gravity pulls it together. The nature of dark energy is
completely unknown, and therefore attracting a lot of experimental and
theoretical attention. "This dark energy could point towards exciting
discoveries in quantum gravity," said Hewett.
SSI attendance "appears to be greater than in recent years
because there is a broad interest in the topic," said organizer Eileen
Everyone at SLAC is welcome to come to the reception on
Monday, July 28 at 6 p.m. outside the Research Office Building, and to the
dinners on July 29, August 4 and August 7 outside the Auditorium. "Great
food and entertainment will be provided, so bring the whole family,"
Brennan said. Dinner tickets are $7 or $4 for students and children, and
will be sold in the Auditorium Breezeway.
To register for the SLAC Summer Institute, see:
For more information contact Eileen Brennan (Ext. 2043,