Press release

Fermilab physicists discover “doubly strange” particle

Batavia, Ill. – Physicists of the DZero experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory have discovered a new particle made of three quarks, the Omega-sub-b (Ωb). The particle contains two strange quarks and a bottom quark (s-s-b). It is an exotic relative of the much more common proton and weighs about six times the proton mass.

The discovery of the doubly strange particle brings scientists a step closer to understanding exactly how quarks form matter and to completing the “periodic table of baryons.” Baryons (derived from the Greek word “barys,” meaning “heavy”) are particles that contain three quarks, the basic building blocks of matter. The proton comprises two up quarks and a down quark (u-u-d).

Combing through almost 100 trillion collision events produced by the Tevatron particle collider at Fermilab, the DZero collaboration found 18 incidents in which the particles emerging from a proton-antiproton collision revealed the distinctive signature of the Omega-sub-b. Once produced, the Omega-sub-b travels about a millimeter before it disintegrates into lighter particles. Its decay, mediated by the weak force, occurs in about a trillionth of a second.

Theorists predicted the mass of the Omega-sub-b baryon to be in the range of 5.9 to 6.1 GeV/c2. The DZero collaboration measured its mass to be 6.165 ± 0.016 GeV/c2. The particle has the same electric charge as an electron and has spin J=1/2.

The Omega-sub-b is the latest and most exotic discovery of a new type of baryon containing a bottom quark at the Tevatron particle collider at Fermilab. Its discovery follows the observation of the Cascade-b-minus baryon (Ξb-), first observed by the DZero experiment in 2007, and two types of Sigma-sub-b baryons (Σb), discovered by the CDF experiment at Fermilab in 2006.

“The observation of the doubly strange b baryon is yet another triumph of the quark model,” said DZero cospokesperson Dmitri Denisov, of Fermilab. “Our measurement of its mass, production and decay properties will help to better understand the strong force that binds quarks together.”

According to the quark model, invented in 1961 by theorists Murray Gell-Mann and Yuval Ne’eman as well as George Zweig, the four quarks up, down, strange and bottom can be arranged to form 20 different spin-1/2 baryons. Scientists now have observed 13 of these combinations.

“The measurement of the mass of the Omega-sub-b provides a great test of computer calculations using lattice quantum chromodynamics,” said Fermilab theorist Andreas Kronfeld. “The discovery of this particle is an example of all the wonderful results pouring out of accelerator laboratories over the past few years.”

The Omega-sub-b is a relative of the famous and “even stranger” Omega-minus, which is made of three strange quarks (s-s-s).

“After the discovery of the Omega-minus, people started to accept that quarks really exist,” said DZero co-spokesperson Darien Wood, of Northeastern University. “Its discovery, made with a bubble chamber at Brookhaven National Laboratory in 1964, is the textbook example of the predictive power of the quark model.”

The DZero collaboration submitted a paper that summarizes the details of its discovery to the journal Physical Review Letters. It is available online at: http://www-d0.fnal.gov/Run2Physics/WWW/results/final/B/B08G/

DZero is an international experiment of about 600 physicists from 90 institutions in 18 countries. It is supported by the U.S. Department of Energy, the National Science Foundation and a number of international funding agencies. Fermilab is a national laboratory funded by the Office of Science of the U.S. Department of Energy, operated under contract by Fermi Research Alliance, LLC.

Photos and graphics of the Large Hadron Collider are available at:
http://multimedia-gallery.web.cern.ch/multimedia-gallery/PhotoGallery_Main.aspx and http://www.uslhc.us/Images.

Fermilab plans September 10 “Pajama Party” to witness first beam at LHC

Batavia, Ill. — Journalists and guests are invited to witness the start-up of the Large Hadron Collider live and in real time at the LHC Remote Operations Center at the Department of Energy’s Fermilab, in Batavia, Illinois in the early morning hours at 1:30 a.m. CDT on Wednesday, September 10. A celebration breakfast will be served following the LHC start-up.

Journalists planning to attend the First-Beam Pajama Party at Fermilab are asked to call the Fermilab Office of Communication at 630-840-2326 or e-mail lizzie@fnal.gov

On September 10, scientists at the Large Hadron Collider in Geneva, Switzerland will attempt for the first time to send a proton beam around the 27-kilometer-long tunnel of the world’s most powerful particle accelerator. Live connections between CERN and Fermilab’s LHC Remote Operations Center will follow the action in Switzerland as it happens.

Beam will begin circulating at about 9 a.m. local time in Switzerland. Due to the time difference between Geneva and Chicago, first beam will occur at about 2 a.m. Chicago time. To allow journalists and guests to watch LHC first-beam operations as they happen, Fermilab will host a “pajama party” at the laboratory, beginning at 1:30 a.m. on Wednesday, September 10.

Fermilab will broadcast a live satellite feed from CERN. Computers in the Remote Operations Center at Fermilab will monitor operations. Scientists from the LHC experiments, CMS and ATLAS, along with accelerator experts, will be on hand to explain first-beam events.

Information about the event is available at http://www.fnal.gov/pajamaparty/. More information about U.S. participation in the LHC and its experiments is available at http://www.uslhc.us.

Fermilab scientists to explain what will happen on September 10

Batavia, Ill. – To answer reporters’ questions about the upcoming startup of the Large Hadron Collider and what it means for research at the Tevatron collider, the Department of Energy’s Fermilab offers a 2-hour Q&A session with Fermilab scientists on Thursday, Sept. 4, from 10:00 a.m. to noon in Wilson Hall. Reporters also will obtain a tour of the LHC Remote Operations Center at Fermilab.

A few days later, on Sept. 10, Fermilab will host a “First-beam Pajama Party” for scientists, guests and media representatives to celebrate the startup of the LHC in real time, at 1:30 a.m. CDT.

At the Q&A session on Sept. 4, four scientists will be on hand to answer in laymen’s terms such questions as “What does the startup mean for the future of Fermilab?”, “How does the LHC startup compare to the Tevatron startup in 1983?” and “Why do scientists build larger and larger accelerators?” The scientists are Peter Limon, who was instrumental in initiating U.S. participation in the LHC construction and who spent 22 months at CERN helping with its installation and commissioning; Dan Green, who’s led the U.S. participation in the construction of the CMS experiment at the LHC; Roger Dixon, who worked on the construction of the Fermilab Tevatron as a staff member and today is the head of the Fermilab Accelerator Division; and Joe Lykken, who has published scientific papers on extra dimensions and other phenomena that the LHC could discover.

The Large Hadron Collider, about 17 miles in circumference, is the largest scientific instrument ever constructed. On Sept. 10, scientists in Geneva, Switzerland, will attempt for the first time to send a proton beam around the ring. More than 1,700 scientists in the United States participate in one of the LHC experiments. The Department of Energy and the National Science

Foundation have contributed a total of $531 million to the construction of the CMS and ATLAS detectors and the LHC machine over twelve years.

Reporters planning to attend the Q&A session on Sept. 4 should send an email to Kurt Riesselmann, kurtr@fnal.gov, or call 630-840-5681.

Reporters planning to attend the First-Beam Pajama Party at Fermilab should call the Fermilab Office of Communication at 630-840-2326 or e-mail Elizabeth Clements at lizzie@fnal.gov.

The Fermi Research Alliance LLC operates Fermilab under a contract with the U.S. Department of Energy.

Photos and graphics of the Large Hadron Collider are available at:
http://multimedia-gallery.web.cern.ch/multimedia-gallery/PhotoGallery_Main.aspx and http://www.uslhc.us/Images.

Fermilab plans September 10 “Pajama Party” to witness first beam at LHC

Batavia, Ill. — Journalists and guests are invited to witness the start-up of the Large Hadron Collider live and in real time at the LHC Remote Operations Center at the Department of Energy’s Fermilab, in Batavia, Illinois in the early morning hours of Wednesday, September 10.

On that date, scientists at the Large Hadron Collider in Geneva, Switzerland will attempt for the first time to send a proton beam around the 27-kilometer-long tunnel of the world’s most powerful particle accelerator. Live connections between CERN and Fermilab’s LHC Remote Operations Center will follow the action in Switzerland as it happens.

Beam will begin circulating at about 9 a.m. local time in Switzerland. Due to the time difference between Geneva and Chicago, first beam will occur at about 2 a.m. Chicago time. To allow journalists and guests to watch LHC first-beam operations as they happen, Fermilab will host a “pajama party” at the laboratory, beginning at 1:30 a.m. on Wednesday, September 10.

Fermilab will broadcast a live satellite feed from CERN. Computers in the Remote Operations Center at Fermilab will monitor operations. Scientists from the LHC experiments, CMS and ATLAS, along with accelerator experts, will be on hand to explain first-beam events.

Journalists planning to attend the First-Beam Pajama Party at Fermilab are asked to call the Fermilab Office of Communication at 630-840-3351 or e-mail jjackson@fnal.gov.

A list of LHC startup events in the U.S. and contact information for each is available at http://www.uslhc.us/first_beam. More information about U.S. participation in the LHC and its experiments is available at http://www.uslhc.us.

Batavia, IL, Berkeley, CA and Upton, NY — On September 10, scientists at the Large Hadron Collider will attempt for the first time to send a proton beam zooming around the 27-kilometer-long accelerator. The LHC, the world’s most powerful particle accelerator, is located at CERN in Geneva, Switzerland. Journalists are invited to attend LHC first beam events at CERN and several locations within the United States. Information about the CERN event and accreditation procedures is available at . A list of LHC startup events in the U.S. and contact information for each is available at http://www.uslhc.us/first_beam.

About 150 scientists from three U.S. Department of Energy Office of Science National Laboratories – Brookhaven National Laboratory on Long Island, Fermi National Accelerator Laboratory in Illinois and Lawrence Berkeley National Laboratory in California – have built crucial LHC accelerator components. They are joined by colleagues from the Stanford Linear Accelerator Center and the University of Texas at Austin in commissioning and continuing R&D for the LHC.

United States contributions to the Large Hadron Collider are supported by the U.S. Department of Energy Office of Science and the National Science Foundation.

The LHC will go for a test drive this weekend, when the first particles are injected into a small section of the LHC. The LHC is the final step in a series of accelerators that bring beam particles from a standstill to energies of 7 TeV. In the injection test this weekend, scientists will make the first attempt to send protons into the LHC, steering them around approximately one-eighth of the LHC ring before safely disposing of the low-intensity beam.

Next up is a series of tests to confirm that the entire LHC machine is capable of accelerating beams to an energy of 5 TeV, the target energy for 2008. On September 10, LHC scientists will go full throttle and try for the first circulating beam. First collisions of protons in the center of the LHC experiments are expected four to eight weeks later.

“We’re finishing a marathon with a sprint,” said CERN’s Lyn Evans, the LHC project leader. “It’s been a long haul, and we’re all eager to get the LHC research program underway.”

About 1,600 scientists from 93 U.S. institutions participate in the LHC experiments, which will analyze the LHC’s high-energy collisions in search of extraordinary discoveries about the nature of the physical universe. The LHC experiments could reveal the origins of mass, shed light on dark matter, uncover hidden symmetries of the universe and possibly find extra dimensions of space.

U.S. first beam events will take place at Fermilab near Chicago, Illinois, Brookhaven Lab in Upton, New York, and in the San Francisco Bay area. More information is available at http://www.uslhc.us/first_beam.
Notes for editors:

More information about U.S. participation in the LHC and its experiments is available at http://www.uslhc.us.

A list of the U.S. institutions participating in the LHC and its experiments is available at: http://www.uslhc.us/The_US_and_the_LHC/Collaborating_Institutions

Fermilab, the U.S. Department of Energy’s Fermi National Accelerator Laboratory located near Chicago, operates the Tevatron, the world’s highest-energy particle collider. The Fermi Research Alliance LLC operates Fermilab under a contract with DOE.

Photos and graphics of the Large Hadron Collider are available at:
http://multimedia-gallery.web.cern.ch/multimedia-gallery/PhotoGallery_Main.aspx and http://www.uslhc.us/Images.

Joint CDF, DZero effort lands Fermilab in Higgs territory

Batavia, Ill. — Scientists from the CDF and DZero collaborations at the U.S. Department of Energy’s Fermilab have combined Tevatron data from the two experiments to advance the quest for the long-sought Higgs boson. Their results indicate that Fermilab researchers have for the first time excluded, with 95 percent probability, a mass for the Higgs of 170 GeV. This value lies near the middle of the possible mass range for the particle established by earlier experiments. This result not only restricts the possible masses where the Higgs might lie, but it also demonstrates that the Tevatron experiments are sensitive to potential Higgs signals.

“These results mean that the Tevatron experiments are very much in the game for finding the Higgs,” said Pier Oddone, director of Fermilab.

Combining results from the two collider experiments effectively doubles the data available for analysis by experimenters and allows each experimental group to cross check and confirm the other’s results. In the near future, the Fermilab experimenters expect to test more and more of the available mass range for the Higgs.

The Standard Model of Particles and Forces–the theoretical framework for particle physics–predicts the existence of a particle, the Higgs boson, that interacts with other particles of matter to give them mass. The mechanism by which particles acquire different mass values is unknown, and finding evidence for the existence of the Higgs boson would address this fundamental mystery of nature.

The CDF and DZero experiments each comprise some 600 physicists from universities and laboratories from across the nation and around the world. Currently, Fermilab’s plans call for the Tevatron experiments to continue operating through 2010. In that time, both groups expect to double their analysis data sets, improving their chances to observe the Higgs.

Scientists expect operations to begin at the Large Hadron Collider at CERN, in Europe, sometime later this year. Observation of the Higgs is also a key goal for LHC experiments.

The Tevatron accelerator and the experiments are operating at peak performance. The Tevatron continues to break records for luminosity, the number of high-energy proton-antiproton collisions it produces. The more luminosity the Tevatron delivers, the more chances experimenters have to see the Higgs. Moreover, by continually improving their experimental techniques, the CDF and DZero physicists have been able to boost their sensitivity to the Higgs and other phenomena by more than the margin afforded by the increased data alone.

“The Fermilab collider program is running at full speed,” said Dennis Kovar, associate director of the Office of Science for High Energy Physics at the U.S. Department of Energy. “In the past year alone, the two experiments have produced 77 Ph.D.s and 100 publications that advance the state of our knowledge across the span of particle physics at the energy frontier.”

The new Higgs results are among the approximately 150 results that the two experiments presented at the International Conference on High Energy Physics in Philadelphia held July 29-August 5.

“The discovery of the Higgs boson would answer one of the big questions in physics today,” said Joseph Dehmer, director of the Division of Physics for the National Science Foundation. “We have not heard the last from the Tevatron experiments.”


Notes for editors:

Fermilab, the U.S. Department of Energy’s Fermi National Accelerator Laboratory located near Chicago, operates the Tevatron, the world’s highest-energy particle collider. The Fermi Research Alliance LLC operates Fermilab under a contract with DOE.

CDF is an international experiment of 635 physicists from 63 institutions in 15 countries. DZero is an international experiment conducted by 600 physicists from 90 institutions in 18 countries. Funding for the CDF and DZero experiments comes from DOE’s Office of Science, the National Science Foundation, and a number of international funding agencies.

CDF collaborating institutions are at http://www-cdf.fnal.gov/collaboration/index.html

DZero collaborating institutions are at http://www-d0.fnal.gov/ib/Institutions.html

More information is available in the conference paper at
http://www-d0.fnal.gov/Run2Physics/WWW/results/prelim/HIGGS/H64/

Fermilab’s DZero experiment observes rare ZZ diboson production

Batavia, Ill.— Scientists of the DZero collaboration at the US Department of Energy’s Fermilab have announced the observation of pairs of Z bosons, force-carrying particles produced in proton-antiproton collisions at the Tevatron, the world’s highest-energy particle accelerator. The properties of the ZZ diboson make its discovery an essential prelude to finding or excluding the Higgs boson at the Tevatron.

The observation of the ZZ, announced at a Fermilab seminar on July 25, connects to the search for the Higgs boson in several ways. The process of producing the ZZ is very rare and hence difficult to detect. The rarest diboson processes after ZZ are those involving the Higgs boson, so seeing ZZ is an essential step in demonstrating the ability of the experimenters to see the Higgs. The signature for pairs of Z bosons can also mimic the Higgs signature for large values of the Higgs mass. For lower Higgs masses, the production of a Z boson and a Higgs boson together, a ZH, makes a major contribution to Higgs search sensitivity, and the ZZ shares important characteristics and signatures with ZH.

The ZZ is the latest in a series of observations of pairs of the so-called gauge bosons, or force-carrying particles, by DZero and its sister Tevatron experiment, CDF. The series began with the study of the already rare production of W bosons plus photons; then Z bosons plus photons; then observation of W pairs; then WZ. The ZZ is the most massive combination and has the lowest predicted likelihood of production in the Standard Model. Earlier this year, CDF found evidence for ZZ production; the DZero results presented on Friday for the first time showed sufficient significance, well above five standard deviations, to rank as a discovery of ZZ production.

“Final analysis of the data for this discovery was done by a thoroughly international team of researchers including scientists of American, Belgian, British, Georgian, Italian and Russian nationalities,” said DZero cospokesperson Darien Wood. “They worked closely and productively together to achieve this challenging and exciting experimental result.”

DZero searched for ZZ production in nearly 200 trillion proton-antiproton collisions delivered by the Tevatron. Scientists used two analyses that look for Z decays into different combinations of secondary particles. One analysis looked for one Z decaying into electrons or muons, the other decaying into “invisible” neutrinos. The neutrino signature is challenging experimentally, but worthwhile because it is more plentiful. In the even rarer mode, both Z bosons decay to either electrons or muons. Just three events were observed in this mode, but the signature is remarkably distinctive, with an expected background of only two tenths of one event.


Notes for editors:

Fermilab, the US Department of Energy’s Fermi National Accelerator Laboratory, located near Chicago, operates the Tevatron, the world’s highest-energy particle collider. The Fermi Research Alliance LLC operates Fermilab under a contract with DOE.

DZero is an international experiment conducted by about 600 physicists from 90 institutions in 18 countries. Funding for the DZero experiment comes from the Department of Energy’s Office of Science, the National Science Foundation, and a number of international funding agencies.

DZero collaborating institutions are at http://www-d0.fnal.gov/ib/Institutions.html

Fermilab Director Pier Oddone expects to announce to all employees the official suspension of involuntary layoffs at Fermilab, as a result of increased funding for science provided in the supplemental funding bill signed by the President today. U.S. Senator Richard Durbin, Congresswoman Judy Biggert, Congressman Bill Foster and Acting Deputy Secretary of Energy Jeffrey Kupfer will make remarks. There will be a brief media opportunity immediately following the meeting.

Media representatives wishing to attend should make arrangements as soon as possible. Please contact Kurt Riesselmann at (630) 840-5681 or kurtr@fnal.gov. To allow for a prompt start for the meeting, media are asked to arrive at Wilson Hall no later than 11:15 a.m.

Craig Hogan to lead particle astrophysics effort

Craig Hogan

Craig Hogan

Craig Hogan, a member of one of the scientific teams that co-discovered dark energy, will soon assume dual roles as Director of the Center for Particle Astrophysics at the Department of Energy’s Fermi National Accelerator Laboratory and as a Professor of Astronomy & Astrophysics at the University of Chicago.

Hogan is a Professor of Astronomy and Physics at the University of Washington and a member of the international High-z Supernova Search Team that in 1998 co-discovered dark energy, the mysterious force that works against gravity to accelerate the expansion of the universe. Hogan’s hiring is the first joint appointment since the University took a major role in managing Fermi National Accelerator Laboratory for the U.S. Department of Energy in 2007.

“Craig Hogan is an outstanding and respected leader in the field of particle astrophysics,” said Fermilab Director Pier Oddone. “I am delighted that he will bring his energy and vision to Fermilab’s Center for Particle Astrophysics, a vital part of Fermilab’s scientific program.”

Chicago scientists founded the field of particle astrophysics at Fermilab during the 1980s, said Edward “Rocky” Kolb, Professor and Chairman of the Department of Astronomy & Astrophysics at the University of Chicago. In this field, scientists study the connections between forces and objects at the largest and smallest scales of the universe.

“Craig is a high-profile scientist, and he sees a great future in the Fermilab-Chicago connection in particle astrophysics,” Kolb said.

Said Hogan: “The cosmology and particle astrophysics community at Fermilab and the University of Chicago continues to lead the world in exploration of the inner space/outer space frontier. It’s a place of great talent, diversity, creativity and intellectual excitement.”

The cosmological frontier is as much about experiments and data as it is about crazy and cool ideas, he said. “The scientists and engineers at Fermilab build incredible machines-devices of unprecedented precision, sensitivity, sophistication and complexity.

“The physicists recognize that in addition to smashing particles in a lab, they can attack deep mysteries of the nature of time, space, matter and energy by using their powerful tools to study the cosmos. This is pushing technology, literally, to the limits-the smallest and biggest things, the farthest and earliest events, the densest and emptiest places, the bits and pieces of space and time themselves.”

Hogan’s University appointment includes affiliations with the Kavli Institute for Cosmological Physics and the Enrico Fermi Institute, where he began his research career in 1980. He will spend 75 percent of his time at Fermilab and 25 percent at the University. Nevertheless, the University will provide 50 percent of his salary as part of its commitment to operating Fermilab through the Fermi Research Alliance.

He is currently a member of two international scientific collaborations: the Large Synoptic Survey Telescope (LSST), and the Laser Interferometer Space Antenna (LISA). The LSST is a proposed 8.4-meter telescope that will image faint astronomical objects thousands of times across the entire sky, including exploding stars and potentially hazardous near-Earth asteroids.

Expected to launch in the next decade, the satellite-based LISA mission will explore and measure the early universe using gravitational waves. These waves, never directly detected, are predicted in Einstein’s theory of general relativity. Hogan also is pursuing theoretical studies of techniques for probing the quantum nature of space time directly in the laboratory.

Hogan earned his bachelor’s degree in astronomy, with highest honors, from Harvard University in 1976, and his Ph.D. in astronomy from King’s College at the University of Cambridge, England, in 1980. He was an Enrico Fermi Fellow at the University of Chicago in 1980-81, a National Science Foundation Postdoctoral Fellow at Cambridge in 1981-82, and a Bantrell Prize Fellow in Theoretical Astrophysics at the California Institute of Technology from 1982-85.

Hogan joined the University of Arizona faculty in 1985, followed by the University of Washington in 1993. At Washington, he served as chair of the Astronomy Department for six years, as Divisional Dean of Natural Sciences for one year and as Vice Provost for Research for more than three-and-a-half years.

His honors include an Alexander von Humboldt Research Award and an Alfred P. Sloan Foundation Fellowship. He also is the author of The Little Book of the Big Bang. Published in 1998 by Springer-Verlag, the book has been translated into six languages.

Fermilab is a DOE Office of Science national laboratory, operated under contract by the Fermi Research Alliance, LLC. The DOE Office of Science is the nation’s single-largest supporter of basic research in the physical sciences.