UA5 experiment

{{short description|Particle physics experiment at CERN}}

{{Use dmy dates|date=January 2018}}

File:Moving UA5 into the beam, CERN, Sep 1981.jpg

File:First proton antiproton collider interactions as seen by the streamer chamber of UA5 in April 1981, CERN.jpg

File:CERN UA5 - ppbar interaction at 540GeV.jpg

The UA5 experiment was the first experiment conducted at the Proton-Antiproton Collider (Sp{{overline|p}}S), a collider using the infrastructure of the Super Proton Synchrotron (SPS). The experiment was approved in February 1979, as a collaboration between CERN and the universities of Bonn, Brussels, Cambridge and Stockholm.{{Cite web|url=https://cds.cern.ch/record/1009444/files/CM-P00063814.pdf|title=Decisions of the 32nd Meeting of the Research Board|last=Goldchmidt-Clermont|first=Y.|date=15 February 1979|website=CERN Document Server|access-date=18 July 2017}} The spokesperson of the UA5 collaboration was John Rushbrooke.{{cite web |url=https://greybook.cern.ch/greybook/experiment/detail?id=UA5 |title=UA5 |author= |website=CERN Greybook |publisher=CERN |access-date=18 July 2017}}

The object of the experiment was to investigate Centauro events and more generally to perform a first rapid visual survey of the energy region afforded by the then new SPS collider.{{Cite journal |last=Rushbrooke |first=John |title=The UA5 Streamer Chamber Experiment at the SPS p-pbar Collider |journal=Physica Scripta |volume=23 |issue=4B |pages=642–648 |doi=10.1088/0031-8949/23/4B/006 |year=1981 |bibcode=1981PhyS...23..642B }} Measurements were done on proton-antiproton collisions of 540 GeV center-of-mass energy, with the results being published in November 1983.{{cite journal|last1=Alpgård|first1=K.|display-authors=etal|title=Particle multiplicities in interactions at √s=540 GeV|journal=Physics Letters B|date=January 1983|volume=121|issue=2–3|pages=209–215|doi=10.1016/0370-2693(83)90916-4|bibcode=1983PhLB..121..209A|url=https://cds.cern.ch/record/141201/files/198212126.pdf}} Later, under the name of UA5/2, data was recorded from 900 GeV collisions.{{cite conference |url=https://cds.cern.ch/record/154847/files/cer-000066115.pdf |title=Results from the UA5 Experiment at the CERN pp-collider |last1=Geich-Gimbel |first1=Ch.|date=9 July 1984 |publisher=Bonn University |location=Durham, UK |conference=VIIth European Symposium on Antiproton Interaction}} No indication of Centauro production was observed, but an upper limit on the production was obtained.

The experimental setup consisted of two large streamer chambers which were placed above and below the Sp{{overline|p}}S beam pipe. The chambers were triggered by requiring hits in scintillation counters at each end. This trigger rejected essentially all elastic and diffractive elements. The streamer chamber tracks were photographed by six cameras, and the tracks were measured, reconstructed and analyzed.