Fermilab

Experiments, Discoveries, & Theory

Fermilab exists to answer fundamental questions about the nature of matter, energy, space, and time. The lab’s original leadership sought to create a user-focused facility that would provide researchers from all over the world with the accelerators and other tools they needed to perform their experiments. Over its history, the lab has hosted a wide variety of experiments and made groundbreaking discoveries possible. As the energy of the accelerators at Fermilab has increased, so has the potential for discovery.

The lab originally had four experimental areas. The first was the Internal Target Area (also known as C-Zero), which was located inside the Main Ring accelerator tunnel. Beamlines from the Main Ring sent particle beams to the three external, fixed target areas: The Neutrino Area, the Meson Area, and the Proton Area. The lab’s experimental program began on February 12, 1972 when the experiment E-36 began testing equipment in the lab’s new beam in the Internal Target Area. One of the lab’s major accomplishments during this era was the discovery of the bottom quark by E-288 with the 400 GeV Main Ring in 1977.

Complementing the lab’s experimental work was the work of the lab’s theoretical physicists. The lab’s first Theory Group was established in the fall of 1969.

Even before the Main Ring or the Fixed Target Areas were completed, lab staff had discussed the possibility of one day introducing a colliding beams program to the lab. Research and development of a proton-antiproton colliding beams program continued into the 1980's. This vision was realized by the Tevatron, which began colliding proton and antiproton beams in 1985. These collisions were studied by the lab’s collider experiments, CDF and DZero. These experiments began observing collisions in 1985 and 1992, respectively. By 1995, the Tevatron reached energies as high as 1.8 TeV, allowing these experiments to discover the top quark. In July 2000, the DONUT collaboration announced the first direct observation of the tau neutrino.

Beginning in the 1980's, the lab also started turning its attention to particle astrophysics. In 1979, lab director Leon Lederman expanded the theory staff, and he added a theoretical astrophysics group in 1983. The lab’s first astrophysics experiment, the Sloan Digital Sky Survey, formed in 1993.

Around the time that the Main Injector accelerator was completed in 1999, the lab began to increase its focus on neutrino physics. The NuMI (Neutrinos at the Main Injector) beamline was completed in 2005. It made MINOS, the lab’s first long-baseline neutrino experiment, possible and laid the groundwork for future long-baseline neutrino experiments.

Below are articles that cover a few of the highlights of the lab’s experiments, discoveries, and theoretical work.

The fixed target areas were the lab’s first experimental areas. The Internal Target Area (also known as C-Zero), was located inside the Main Ring accelerator tunnel. Particle beams were extracted from the Main Ring and sent to the Switchyard, which sent beamlines to the three external, fixed target areas: The Neutrino Area, the Meson Area, and the Proton Area. The Meson Area provided six secondary beams, the Neutrino Area supplied neutrino and muon beams, and the Proton Area consisted of three beamlines called P-West, P-Center, and P-East. The Tevatron fixed target program ran from 1983 to 2000.

General

Internal Target

The Internal Target at CZero was the location for the first experiment performed at Fermilab. This experiment, E-36, was a collaboration of American and Soviet physicists that started in 1972.

Meson Area

The Meson Laboratory was constructed in the early 1970s in the Fixed Target Area. The unique architectural landmark is made of inverted culvert and was painted blue and orange, appearing orange from the North and blue from the South.

Neutrino Area

The Neutrino Laboratory has the longest beamline in the Fixed Target Area. The 15-foot Bubble Chamber was the featured detector at the end of the beamline, near Wilson Road. An important early experiment in this area was E-1A, which searched for evidence of neutral currents.
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Proton Area

The Proton Laboratory was the last of the Fixed Target Areas to be constructed. It was the site of the discovery of the bottom quark by E-288 in 1977.

One of the lab’s major accomplishments during the fixed target era was the discovery of the bottom quark by experiment E-288 in 1977. This experiment was based in the proton fixed target area and led by Leon M. Lederman. It was made up of scientists from Columbia, Fermilab, and the State University of New York at Stony Brook. The experiment sought to study the rare events that occur when a proton beam collides with a platinum target, producing a pair of muons or electrons. The experimenters observed a bump in the number of events at 9.5 GeV, indicating the existence of the upsilon particle, which was later understood to be the bound state of the bottom quark and its antiquark.

The experiment began with a proposal for E-70, which was submitted on June 17, 1970. The third phase of E-70 ultimately became E-288. The experimenters began taking data for E-288 on May 15, 1977. A fire in the Proton Center pit on May 22 briefly delayed the experiment, but they were able to resume operations on May 27. By June 15, the experimenters were confident in their results, and Steve Herb announced the discovery at a June 30 seminar in the Fermilab Auditorium. Physical Review Letters received the experimenters' paper "Observation of a Dimuon Resonance at 9.5 GeV in 400-GeV Proton-Nucleus Collisions" on July 1.

The E288 experimenters included J. A. Appel, B. C. Brown, C. N. Brown, W. R. Innes, K. Ueno, and T. Yamanouchi from Fermilab; S. W. Herb, D. C. Hom, L. M. Lederman, J. C. Sens, H. D. Snyder, and J. K. Yoh from Columbia University; and A. S. Ito, H. Jostlein, D. M. Kaplan, and R. D. Kephart from Stony Brook.

Documents

Articles

As early as 1967, laboratory staff had informally discussed the possibility of having colliding particle beams at the lab, which would allow the lab to produce higher energy collisions. In the following years, groups of scientists proposed several possible plans for creating and using colliding beams at Fermilab, including the Electron Target Project and POPAE (Protons on Protons and Electrons). The lab’s plans became more focused at the January 1976 “Modest Colliding-Beams Meeting” organized by Alvin Tollestrup. This meeting established colliding beams as a high priority for the lab and drove elements of the design of the “Energy Doubler” accelerator, which would later be known as the Tevatron. On November 17, 1976, lab director Robert Wilson established the Colliding Beams Department, but this department disbanded in the fall of 1977. In January 1978, its efforts were revived with the establishment of the Colliding Detector Facility Department under Tollestrup’s leadership. This work led to the development of the CDF detector and experiment based at the BZero location on the Main Ring. Later, second lab director Leon Lederman decided that the lab should build a complementary colliding-beam detector facility at DZero. He asked for preliminary proposals for such a detector in February 1981. CDF and DZero would ultimately become the lab’s flagship experiments and jointly discovered the top quark in 1995.

General

CDF

Fermilab’s CDF experiment (an effort that was originally called the Colliding Detector Facility and later the Collider Detector at Fermilab) developed in parallel with Fermilab’s colliding beams accelerator program. Lab director Robert Wilson established the Colliding Beams Department under the leadership of Jim Cronin on November 17, 1976. When that department dissolved in the fall of 1977, some of its work was taken on by the Colliding Detector Facility Department under the leadership of Alvin Tollestrup. In 1980, Roy Schwitters joined the group as CDF’s associate head. By that time, the collaboration included institutions from the U.S., Italy, and Japan. In August 1981, the group produced a conceptual design report. They broke ground for the experiment’s collision hall at BZero on July 1, 1982 and construction was completed in March 1983. Simultaneously, in late 1981, they began constructing the 2,000-ton CDF detector. On October 13, 1985, the detector observed its first collisions. In 1995, CDF and DZero would discover the top quark together. CDF took data until the Tevatron’s shutdown in 2011. See also: INSPIRE-HEP records for the CDF experiment and upgrades: E-0741, E-0775, E-0830, and E-0876.

DZero

In 1981, lab director Leon Lederman asked for preliminary proposals for a "modest detector built by a modestly sized group" that would be located at DZero and complement the CDF detector. More than fifteen groups submitted proposals. Three of these proposals were merged into one effort under the leadership of Paul Grannis, which officially began on September 1, 1983. The group produced a design report in November 1984. The detector was completed in 1990, it was placed in the Tevatron in February 1992, and observed its first collision in April or May 1992. In 1995, DZero and CDF discovered the top quark together. DZero took data until the Tevatron’s shutdown in 2011. See also: INSPIRE-HEP records for the DZero experiment and upgrades: E-0740 and E-0823.

One of the primary goals of the Tevatron, CDF, and DZero was the discovery of the top quark, the last of the six quarks predicted by the Standard Model of physics. Because the top quark is so short-lived, the scientists painstakingly analyzed the decay products this massive particle produced in their detectors to identify it. CDF scientists announced preliminary evidence of the top quark in April of 1994, and CDF and DZero jointly announced the discovery of the top quark on March 2, 1995. They had simultaneously submitted papers describing observations of the top quark to Physical Review Letters on Friday, February 24.

Astrophysics became part of Fermilab’s scientific program under second lab director Leon Lederman. Lederman hired Michael Turner and Edward “Rocky” Kolb in 1983 to start the Fermilab/NASA Theoretical Astrophysics Group. In 1984, the lab held its first “Inner Space-Outer Space” conference. This conference, which explored the connections between particle physics and cosmology, was a milestone event in the field of particle astrophysics. In 1993, the lab’s first experimental astrophysics work began with the start of the Sloan Digital Sky Survey. The lab later became involved in projects like the Dark Energy Survey and the Pierre Auger Observatory. In 2004, the lab established the Fermilab Particle Astrophysics Center.

General

Sloan Digital Sky Survey

The Sloan Digital Sky Survey (SDSS) was the lab’s first astrophysics experiment. It started in 1993 and received “first light” (made its first observations) the night of May 9-10, 1998. John Peoples, Fermilab’s third director, served as director of SDSS from 1998 to 2003. The survey started a second run in July 2005 and a third in 2008. See also: the INSPIRE-HEP records for SDSS, SDSS-II, SDSS-III, SDSS-IV, and BOSS.

Dark Energy Survey

Scientists from Fermilab, the University of Illinois at Urbana-Champaign, the University of Chicago, and Lawrence Berkeley National Laboratory submitted a proposal for the Dark Energy Survey (DES) to the National Optical Astronomy Observatory on July 15, 2004. The main tool of the survey was the Dark Energy Camera (DECam), built at Fermilab and mounted on the Victor M. Blanco telescope at the National Science Foundation’s Cerro Tololo Inter-American Observatory in the Andes Mountains in Chile. It took its first images on August 31, 2013 and completed data-taking on January 9, 2019. See also: the INSPIRE-HEP record for DES.

Fermilab's experiment E-872, also called DONUT (Direct Observation of the Nu Tau), was a fixed-target experiment formed to observe the tau neutrino. The experiment's proposal was approved in 1994, it began taking data on April 14, 1997, and the experimenters announced the first direct evidence of the tau neutrino on July 21, 2000. See also: DONUT's INSPIRE-HEP record.

Fermilab's long-baseline neutrino program began with the construction of the NuMI (Neutrinos at the Main Injector) beam and the MINOS (Main Injector Neutrino Oscillation Search) experiment.

MINOS

MINOS, the Main Injector Neutrino Oscillation Search, was Fermilab's first long-baseline neutrino experiment. The NuMI beam sent a beam of neutrinos from Fermilab in Batavia, Illinois to the Soudan Mine in northern Minnesota. A "near" detector analyzed the beam close to its source on the Fermilab site while a larger "far" detector in Minnesota looked for changes in the neutrino beam. MINOS was first proposed in the early 1990s. It was approved for construction in 1995 and the lab broke ground on the experiment in Minnesota on July 20, 1999. The far detector was completed in July 2003, and the experiment began taking data on August 14, 2003 with the detection of atmospheric neutrinos created by cosmic rays. The experiment was dedicated on March 4, 2005. During its run, MINOS set constraints on parameters related to neutrino oscillations and on the properties of hypothesized sterile neutrinos. The second phase of MINOS, MINOS+, began in 2013. On June 29, 2016, the MINOS experiment concluded. See also: The INSPIRE-HEP records for MINOS and MINOS+.

NOvA

NOvA, the NuMI Off-Axis Electron Neutrino Appearance experiment, is Fermilab's second long-baseline neutrino experiment and the successor to MINOS. The NuMI beam sends a beam of neutrinos from Fermilab in Batavia, Illinois to Ash River, Minnesota. A "near" detector analyzes the beam close to its source on the Fermilab site while a larger "far" detector in Minnesota looks for changes in the neutrino beam. NOvA was proposed in March 2004. The lab broke ground on the experiment in Ash River, Minnesota on May 1, 2009. The experiment collaborators observed the first neutrinos from the Fermilab beam in November 2013. Construction was completed in September 2014. The NOvA experiment studied neutrinos until February 2017, when it began studying antineutrinos. See also: the INSPIRE-HEP record for NOvA.

DUNE

DUNE (the Deep Underground Neutrino Experiment) is Fermilab's third planned long-baseline neutrino experiment. The experiment, which was originally called simply LBNE (Long-Baseline Neutrino Experiment), will send a beam of neutrinos from Fermilab to the Sanford Underground Research Facility in South Dakota. The collaboration formed on January 22, 2015. See also: the INSPIRE-HEP records for LBNE, ProtoDUNE-SP, ProtoDUNE-DP, and DUNE.

On July 4, 2012, CERN's CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC ApparatuS) collaborations announced the discovery of the Higgs boson. Fermilab served as the hub for nearly 1,000 U.S. scientists and engineers who participated in the CMS experiment, hosting the LHC Physics Center (LPC) and CMS Remote Operations Center and also serving as a Tier-1 computing center for LHC data.

Fermilab has hosted hundreds of experiments in its more than fifty-year history. These are a few other noteworthy experiments that lab has been involved in.

NuTeV

The NuTeV (Neutrinos at the Tevatron) experiment discovered an imbalance of neutrinos and muons emerging from high-energy collisions of neutrinos with target nuclei. The experiment was proposed in 1990, started in 1996, and completed its run in 1997. See also: the INSPIRE-HEP record for E-815.

KTeV

The KTeV collaboration established the existence of direct CP violation in the decay of kaon particles in 1999. The experiment was proposed in 1990 and began running in 1996. See also: The INSPIRE-HEP record for E-0832

Pierre Auger Observatory

The Pierre Auger Observatory is an international collaboration using a large array of detectors in Argentina to measure the arrival direction, energy, and mass composition of air showers created by high-energy cosmic rays. The experiment was proposed in 1995 and began running in 2005. See also: The INSPIRE-HEP record for AUGER

COUPP

The COUPP (Chicagoland Observatory for Underground Particle Physics) experiment used bubble chamber technology to search for dark matter. The experiment was proposed in 2006 and completed its run in 2011. See also: the INSPIRE-HEP record for E-961.

Muon g-2

The Muon g-2 experiment seeks to measure the muon anomalous magnetic moment to 0.14 ppm. The experiment received significant press coverage in 2013 when a large electromagnet was moved from Brookhaven National Laboratory in New York to Fermilab for use in this experiment. The experiment was proposed in 2009 and began running in 2017. See also: the INSPIRE-HEP record for E-989.

The lab’s first Theory Group, consisting of five theorists, was established in the fall of 1969. The appointments of most of this original group were terminated in September 1971. In the fall of 1972, the Theory Group started "The Joint Experimental-Theoretical Seminar" which was later informally named "The Wine and Cheese Seminar" and became a lab tradition. Benjamin Lee led the group from 1973 until his death in 1977. In 1979, lab director Leon Lederman expanded the theory staff, and he added a theoretical astrophysics group in 1983.