Thursday, June 10|
THERE WILL BE NO THEORETICAL PHYSICS SEMINAR THIS WEEK
3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over
THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY
Friday, June 11
3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over
4:00 p.m. Joint Experimental Theoretical Physics Seminar - 1 West
Speaker: K. Yorita, Waseda University
Title: Top Mass Measurement in Run II at CDF Using the
Dynamic Likelihood Method
Thursday, June 10|
Grilled Chicken Cordon Bleu Sandwich $4.75
Peachy Pork Roast $3.75
Chicken Marsala $3.75
Maryland Crab Salad $4.75
Italian Sausage Calzones $3.75
SW Chicken Salda with Roasted Corn Salsa $4.75
Wilson Hall Cafe Menu
Day of Mourning For Reagan Declared|
In honor of the passing of former President Ronald Reagan, tomorrow has
been declared a National Day of Mourning. Fermilab will remain
open tomorrow, but all employees are encouraged to honor the memory
of the former President in their own ways. Visit the official
Ronald Reagan Memorial website, which includes access to funeral service
information, a condolence book, tributes, and a memorial fund.
Fermilab's 15-Foot Bubble Chamber Relocated|
|With the help of a contractor,
FESS engineers used a hydraulic
lift to move the 15-foot bubble chamber to the SiDet courtyard. (Click on image
for larger version.)|
A 281-ton bubble chamber, Fermilab's oldest particle detector, has become the lab's most valuable lawn ornament.
From 7:00 a.m. to noon on Tuesday, FESS and contractor Belding Walbridge used a hydraulic lift to move the
enormous metal sphere from its holding space in Lab A and placed it outside
on a concrete pedestal in the SiDet courtyard,
where it will remain on display.
"It cost $200 million to build Fermilab, and the bubble chamber was $25
million on top of that," said John Cooper of the Particle Physics Division.
"Bubble chambers were the premier detectors -- the CDFs or DZeros of the 1960s."
Installed in 1973, the 15-foot bubble chamber allowed Fermilab physicists
to track elusive high-energy particles like kaons, lambdas, and electrons, and
provided detailed views of decay vertices. Particles penetrating the
superheated hydrogen inside the chamber left bubble tracks, which could
be photographed and reconstructed in 3D. Though the chamber was unable to
process multiple, or even successive particle collisions, its high quality imaging has been surpassed only recently by the newest generation of particle detectors.
It was used in 17
experiments over a period of 15 years. "Bubble chambers played an
instrumental role in several early discoveries,"
said Dixon Bogart, associate head of the Accelerator Division. "It was one
of the first major pieces of experimental equipment built at the lab."
The move prompted nostalgia. "I saw the chamber first lowered into the ground
when I was a little kid," said Pete Simon, building manager at DZero.
His father, George Simon, who was also present yesterday, had operated
the device from 1973 to 1987. "It was hard work, but always interesting,"
George Simon said. "But you had to keep an eye on it constantly."
Streaming Video: Fermilab Bubble Chamber Moved
From Nature Magazine, June 9, 2004|
Particle physics: From the top...
by Georg Weiglein
The basic building-blocks of matter, as far as we know, are quarks and leptons, together with the force-carrying particles that mediate their interactions. Quarks and leptons (the latter group including the electron) are grouped in three generations; the particles in the second and third generations seem a perfect copy of those of the first generation, except that their masses are much larger. The top quark is the heaviest of all quarks and leptons, and is central to some of the most pressing questions in particle physics. For instance, why is the third-generation top quark more than 300,000 times heavier than the first-generation electron? Why are there two other quarks with precisely the same properties as the top quark but with very different masses? And what is the origin of mass itself?
A New Determination of Vus by KTeV|
Comparison of KTeV and PDG averages for the six largest K-long branching
fractions. (Click on image for larger version.)|
Although the neutral kaon was discovered more than 50 years ago, it
continues to be a unique tool for particle physics. The KTeV
collaboration has recently completed a series of measurements of
neutral kaon decay, resulting in a new determination of the CKM matrix
The CKM matrix describes the coupling of the u, c, and t quarks to
the d, s, and b quarks. Much recent attention has been given to the
possible deviation from unitarity in the first row of this matrix.
There has been particular interest in checking the Vus element (describing the
coupling of s quarks to u quarks), because it was based on averages of
dozens of experiments done over a 40 year period.
To determineVus, KTeV has measured the six largest KL branching
(accounting for more than 99.9% of all K-long decays) and the form
factors in semileptonic kaon decays. This work marks the first time these
measurements have all been performed together in a modern, high
statistics experiment. The KTeV branching fraction measurements are about a factor
of two more precise than the averages of all previous measurements, but
are not in good agreement with the averages. In particular, the
important KL to pi e nu branching fraction is about 5% higher than the previous
world average. This shift is consistent with the higher semileptonic
branching fraction recently measured in K+ decay by Brookhaven
experiment E865. The new KTeV results are consistent with unitarity of the first
row of the CKM matrix.
Articles reporting these results were submitted to Physical Review
Letters and Physical Review D on June 1.
|This analysis was done by (left to right)
Rick Kessler, Ed Blucher, and Sasha Glazov of the University of Chicago. (Click on image for larger version.)|
Result of the Week Archive
Fermilab Results Change Higgs Mass Estimate|
Scientists at Fermilab announced on June 9, 2004 new results that change
the best estimate of the mass of the postulated Higgs boson from approximately
96 GeV/c2 to 117 GeV/c2. Compared to the previous value,
the new value is in better agreement with direct searches - such as those
conducted by CERN experiments - that excluded a mass below 114 GeV/c2.
In a paper to appear in the June 10 issue of Nature magazine, physicists of
Fermilab's DZero experiment report on results obtained by applying a new
analysis technique to data obtained from 1992 to 1996 during Collider Run
I at the Fermilab Tevatron, the world's highest-energy particle accelerator.
Visualization of a|
Run II collision
that produced a top
quark in 2002,
recorded by DZero.
June 7 - June 9|
- Operations established one store during this 48 hour period that
combined with an existing store provided approximately 42 hours and 21 minutes of luminosity
to the experiments.
- TeV sets NEW initial luminosity record of 76.8446E30
- TeV registers mysterious beam spike on Tuesday morning
- Off site power glitch causes many devices to trip off. Store
- TeV, MI, Pbar, and Recycler prepare for Mixed Mode antiproton
View the current accelerator update
View the Tevatron Luminosity Charts
New Books in the Fermilab Library|
New books in the Fermilab Library for the week of June 8
are now on display in the Library near the front desk. An online list
of the new books is now available.
New books may be reserved by using the
online Library catalog
or by calling the library at x3401, or by filling out
the reserve card in the book.
Fermilab June Golf Outing
The first golf outing of the year will be on Friday, June 25th. This
outing is open to everyone (no handicap is required). It will be a
1:00 shotgun start at Mill Creek Golf Club in Geneva. The entry fee is
$55 per person and includes green fees, cart, and all event contests.
Deadline to sign up is June 14th. For more information or to sign up,
contact Tim Gierhart,
x5070 or Jerry Leibfritz,