[[File:WA70 calorimeter.jpg|alt=WA70 calorimeter.|thumb|The WA70 calorimeter viewed from downstream of the beam line. Photo by R.W. Poultney 1986]] The '''WA70 experiment''' was a collaboration between the Universities of [[University of Geneva|Geneva]], [[University of Glasgow|Glasgow]], [[University of Liverpool|Liverpool]], [[University of Milan|Milan]] and [[University of Neuchâtel|Neuchatel]] using the facilities of the OMEGA spectrometer at [[CERN]].<ref name="BonvinBopp1989">{{cite journal|last1=Bonvin|first1=E.|last2=Bopp|first2=R.|last3=Carroll|first3=L. J.|last4=Cass|first4=A. J.|last5=Chung|first5=S. U.|last6=Donnat|first6=M.|last7=Dorsaz|first7=P. A.|last8=Feliks|first8=M. E.|last9=Fluri|first9=L.|last10=Jackson|first10=J. N.|last11=Kienzle-Focacci|first11=M. N.|last12=Lynch|first12=J. G.|last13=Martin|first13=M.|last14=Mathys|first14=L.|last15=Negus|first15=P. J.|last16=Perini|first16=L.|last17=Poultney|first17=R.|last18=Range|first18=W. H.|last19=Rosselet|first19=L.|last20=Snow|first20=S. W.|last21=Thompson|first21=A. S.|last22=Turnbull|first22=R. M.|last23=Werlen|first23=M.|title=Double prompt photon production at high transverse momentum byπ − on protons at 280 GeV/c|journal=Zeitschrift für Physik C|volume=41|issue=4|year=1989|pages=591–598|issn=0170-9739|doi=10.1007/BF01564702|s2cid=119370172|url=https://cds.cern.ch/record/191522}}</ref>
The purpose of the experiment was to study [[direct photons]] produced in [[proton]]-[[proton]] and [[proton]]-[[pion]] collisions within a fixed target of [[liquid hydrogen]] at the [[Super Proton Synchrotron|CERN SPS]].<ref name=proposal /> The experiment was proposed on 6 August 1980 <ref name=proposal /> and formally approved on 22 October 1981.<ref>{{cite report |date=23 October 1981 |title=Decision of the 54th Meeting of the Research Board held on 22 October 1981 |url=https://cds.cern.ch/record/1014193/files/CM-P00060196.pdf |publisher=CERN |docket=CERN-DG-RB-81-21 |access-date=28 January 2020}}</ref> Preliminary data was taken in 1983 with physics runs in 1984, 1985 and 1986.<ref>{{cite web |url=https://greybook.cern.ch/greybook/experiment/detail?id=WA70 |title= WA70/OMEGA/DIRPHOTON : Study of Direct Photon Events in Hadronic Collisions |website=The CERN Experimental Programme |publisher=CERN |access-date=28 January 2020 }}</ref>
A novel feature of the experiment was a liquid scintillator [[Calorimeter (particle physics)|calorimeter]],<ref>{{Cite journal|last=Bonesini|display-authors=etal|first=M.|date=1987|title=A Lead-Liquid Scintillator Electromagnetic Calorimeter for Direct Photon Physics|journal=Nuclear Instruments and Methods|volume=A261|issue=3|pages=471–480|doi=10.1016/0168-9002(87)90356-1|bibcode=1987NIMPA.261..471B}}</ref> which was built in quadrants and designed to measure the energy of [[direct photons]] and other particles produced by the collisions. This was situated downstream of the [[liquid hydrogen]] target.
Results were presented at scientific conferences and published in scientific journals.<ref>{{cite web |url=https://cds.cern.ch/search?ln=en&cc=CERN+Published+Articles&p=experiment%3Awa70&action_search=Search&op1=a&m1=a&p1=&f1=&c=CERN+Published+Articles&c=&sf=&so=a&rm=&rg=50&sc=1&of=hb |title=List of WA70 publications recorded by CERN |website=CERN Document Server (CDS) |publisher=CERN |access-date=28 January 2020}}</ref> The measured [[Cross section (physics)|cross section]] for direct photon production was in agreement with predictions from perturbative [[Quantum chromodynamics|QCD]].<ref name="Martin1988">{{cite book|last1=Martin|first1=Michel|title=QCD Hard Hadronic Processes|chapter=Direct Photon Production by π-p, π+p and pp Interaction at 280 GeV/c: Results from the WA70 Experiment at CERN|series=NATO ASI Series|volume=197|year=1988|pages=113–124|issn=0258-1221|doi=10.1007/978-1-4684-8842-5_9|isbn=978-1-4684-8844-9}}</ref>
The spokesperson for the experiment was Professor Michel Martin,<ref name=proposal>{{cite report |last=Bachmann |first=L.|date=6 August 1980 |title=Proposal to the SPSC : study of direct photon events in hadronic collisions |url=https://cds.cern.ch/record/601279/files/cm-p00045423.pdf |publisher=CERN |docket=CERN-SPSC-80-61; SPSC-P-147 |access-date=28 January 2020}}</ref> and participants included Dr. [[Fabiola Gianotti]]<ref>{{cite web |url=http://inspirehep.net/search?ln=en&p=find+au+Gianotti+and+exp+CERN-WA-070&of=hb&action_search=Search&sf=earliestdate&so=d |title=Recorded WA70 publications with Fabiola Gianotti as author |website=INSPIRE-HEP |access-date=28 January 2020}}</ref> (who went on to become [[CERN]]'s first woman [[List of Directors General of CERN|Director General]]).
==References== {{reflist}}
== External links == * [https://inspirehep.net/experiments/1109441 CERN-WA-070 experiment record] on [[INSPIRE-HEP]]
[[Category:Particle experiments]] [[Category:CERN experiments]]