The central section of the UA1 experiment on display at the Microcosm museum at CERNInterior of the central section of the UA1 experiment on display at the Microcosm museum at CERN
The UA1 experiment (an abbreviation of Underground Area 1) was a high-energy physics experiment that ran at CERN's Proton-Antiproton Collider (SppS), a modification of the one-beam Super Proton Synchrotron (SPS). The data was recorded between 1981 and 1990. The joint discovery of the W and Z bosons by this experiment and the UA2 experiment in 1983 led to the Nobel Prize for physics being awarded to Carlo Rubbia and Simon van der Meer in 1984. Peter Kalmus and John Dowell, from the UK groups working on the project, were jointly awarded the 1988 Rutherford Medal and Prize from the Institute of Physics for their outstanding roles in the discovery of the W and Z particles.
It was named as the first experiment in a CERN "Underground Area" (UA), i.e. located underground, outside of the two main CERN sites, at an interaction point on the SPS accelerator, which had been modified to operate as a collider.
The UA1 central detector was crucial to understanding the complex topology of proton-antiproton collisions. It played a most important role in identifying a handful of W and Z particles among billions of collisions.[1]
Section of the UA1 detector at Museo nazionale della scienza e della tecnologia Leonardo da Vinci of Milan
After the discovery of the W and Z boson, the UA1 collaboration went on to search for the top quark. Physicists had anticipated its existence since 1977, when its partner — the bottom quark — was discovered. It was felt that the discovery of the top quark was imminent. In June 1984, Carlo Rubbia at the UA1 experiment expressed to the New York Times that evidence of the top quark "looks really good".[2] Over the next months it became clear that UA1 had overlooked a significant source of background.[3] The top quark was ultimately discovered in 1994–1995 by physicists at Fermilab with a mass near 175 GeV.
The UA1 was a huge and complex detector for its day. It was designed as a general-purpose detector.[4]
The detector was a 6-chamber cylindrical assembly 5.8 m long and 2.3 m in diameter, the largest imaging drift chamber of its day. It recorded the tracks of charged particles curving in a 0.7 Tesla magnetic field, measuring their momentum, the sign of their electric charge and their rate of energy loss (dE/dx). Atoms in the argon-ethane gas mixture filling the chambers were ionised by the passage of charged particles. The electrons which were released drifted along an electric field shaped by field wires and were collected on sense wires. The geometrical arrangement of the 17000 field wires and 6125 sense wires allowed a spectacular 3-D interactive display of reconstructed physics events to be produced.[5]
The UA1 detector was conceived and designed in 1978/9, with the proposal submitted in mid-1978.[6]
Since the end of running, the magnet used in the UA1 experiment has been used for other high energy physics experiments, notably the NOMAD and T2K neutrino experiments.
^"ua1 central detector: Topics by WorldWideScience.org". Archived from the original on 2011-10-03.
^Sullivan, Walter. "Physicists May Have Tracked Last Quark to Lair". The New York Times. No. 25 June 1984. Retrieved 23 June 2017.
^Staley, Kent W. (2004). The Evidence for the Top Quark: Objectivity and Bias in Collaborative Experimentation. Cambridge University Press. p. 80.
^"The UA1 detector - CERN Courier". Archived from the original on 2012-03-19.
^"ua1 central detector: Topics by WorldWideScience.org". Archived from the original on 2011-10-03.
^"When CERN saw the end of the alphabet". CERN Courier. 1 May 2003.
The UA1experiment (an abbreviation of Underground Area 1) was a high-energy physics experiment that ran at CERN's Proton-Antiproton Collider (SppS),...
CERN. The experiment ran from 1981 until 1990, and its main objective was to discover the W and Z bosons. UA2, together with the UA1experiment, succeeded...
limits for squarks and gluinos were made at CERN by the UA1experiment and the UA2 experiment at the Super Proton Synchrotron. LEP later set very strong...
Z bosons which could be detected for the first time in 1983 by the UA1experiment, led by Carlo Rubbia. The W and Z bosons had been theoretically predicted...
surrounded by the electromagnetic calorimeter and a magnet recycled from the UA1experiment producing 0.2 T uniform horizontal magnetic field and instrumented with...
monopoles was found by the UA3 experiment. The experiment shares the same intersection region used as the UA1 colliding experiment, and looked for expected...
crucial evidence for the existence of quarks. Proton Synchrotron UA1experiment UA2 experiment W and Z bosons Bubble chamber "Gargamelle". CERN. Retrieved...
it was called SppS), when its beams provided the data for the UA1 and UA2 experiments, which resulted in the discovery of the W and Z bosons. These discoveries...
data collected. List of Super Proton Synchrotron experimentsUA1experiment UA4 experiment UA5 experiment CERN Greybook entry for UA7 "Greybook". greybook...
pulsed mode, to 900 GeV). Several experiments recorded data from the collisions, most notably the UA1 and UA2 experiment, where the W and Z bosons were discovered...
and led to the discovery of the W and Z bosons in 1983 (at the UA1 and UA2 experiments). Recently, bubble chambers have been used in research on weakly...
NA58 experiment, or COMPASS (standing for "Common Muon and Proton Apparatus for Structure and Spectroscopy") is a 60-metre-long fixed-target experiment at...
University of Birmingham, which he was awarded in 1989 for work on the UA1experiment, searching for the top quark. Charlton's research investigates the Higgs...
international team of more than 100 physicists headed by Rubbia and known as the UA1 Collaboration, detected the intermediate vector bosons, the W and Z bosons...
Gargamelle bubble chamber; 1983: The discovery of W and Z bosons in the UA1 and UA2 experiments; 1989: The determination of the number of light neutrino families...
Area (NA experiments), West Area (WA experiments), Underground Area (UA experiments), and the Endcap MUon detectors (EMU experiments). The UA1 and UA2...
demonstrated by the NA14 photoproduction experiment at CERN in the mid-eighties. Following NA14 he joined the UA1experiment at CERN's proton-antiproton collider...
January 1983 during a series of experiments made possible by Carlo Rubbia and Simon van der Meer. The actual experiments were called UA1 (led by Rubbia) and UA2...
her undergrad, which leads her to get a job at CERN for a year on the UA1experiment. This experience at CERN plays a big impact on her ultimate career path...
diffraction" was born. List of Super Proton Synchrotron experimentsUA1experiment UA2 experiment Bonino; et al. (26 October 1984). "Proposal to SPSC: Study...
NA61/SHINE (standing for "SPS Heavy Ion and Neutrino Experiment") is a particle physics experiment at the Super Proton Synchrotron (SPS) at the European...
A list of particle accelerators used for particle physics experiments. Some early particle accelerators that more properly did nuclear physics, but existed...
reconstructed and analyzed. List of Super Proton Synchrotron experimentsUA1experiment UA2 experiment Goldchmidt-Clermont, Y. (15 February 1979). "Decisions...
notable experiments in physics. The list includes only experiments with Wikipedia articles. For hypothetical experiments, see thought experiment. Bell tests...
indeed rises with energy. List of Super Proton Synchrotron experimentsUA1experiment UA2 experiment "UA4/COULOMB". CERN Greybook. Retrieved 19 July 2017....
and the Glast satellite. From 1984 to 1988, Grassmann was part of the UA1experiment at CERN in Geneva, where he wrote his PhD thesis. From 1987 to 1999...
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