OPERA experiment
Italian neutrino detector (2011–2012)
title: "OPERA experiment" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["neutrino-experiments", "cern-experiments"] description: "Italian neutrino detector (2011–2012)" topic_path: "general/neutrino-experiments" source: "https://en.wikipedia.org/wiki/OPERA_experiment" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Italian neutrino detector (2011–2012) ::
The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) was an instrument used in a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. The experiment is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy and uses the CERN Neutrinos to Gran Sasso (CNGS) neutrino beam.
The process started with protons from the Super Proton Synchrotron (SPS) at CERN being fired in pulses at a carbon target to produce pions and kaons. These particles decay to produce muons and neutrinos. |last = Al-Khalili |first = J. |date = 18 November 2011 |title = Faster than the speed of light? |url = http://www.jimal-khalili.com/blog/faster-than-the-speed-of-light.html#more-1055 |work = Jim's Blog |access-date = 2013-08-31 |url-status = dead |archive-url = https://web.archive.org/web/20140201230116/http://www.jimal-khalili.com/blog/faster-than-the-speed-of-light.html#more-1055 |archive-date = 1 February 2014
The beam from CERN was stopped on 3 December 2012, ending data taking, but the analysis of the collected data has continued.
Detector
::figure[src="https://upload.wikimedia.org/wikipedia/commons/7/74/OPERA.jpg" caption="View of the OPERA detector at the CNGS facility"] ::
OPERA, in Hall C of the Gran Sasso underground labs, was built in 2003–2008. The taus resulting from the interaction of tau neutrinos are observed in "bricks" of photographic films (nuclear emulsion) interleaved with lead sheets. Each brick weighs 8.3 kg; the two OPERA supermodules contain 150,000 bricks arranged into parallel walls interleaved with plastic scintillator counters. Each supermodule is followed by a magnetic spectrometer for momentum and charge identification of penetrating particles. During data collection, a neutrino interaction and its corresponding brick are tagged in real time by the scintillators and spectrometers. These bricks are extracted from the walls asynchronously with respect to the beam for film development, scanning and for the topological and kinematic search of tau decays.{{cite web |title=The Opera Detector |url=http://operaweb.lngs.infn.it/spip.php?rubrique39 |publisher=OPERA |access-date=2011-09-25 |archive-date=11 February 2019 |archive-url=https://web.archive.org/web/20190211183031/http://operaweb.lngs.infn.it/spip.php?rubrique39 |url-status=dead
Tau neutrinos
::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/cc/OPERA_neutrino.jpg" caption="First neutrino events seen by the core of the OPERA experiment"] ::
In total, five tau neutrinos were detected. On 31 May 2010, OPERA researchers observed the first tau neutrino candidate event in a muon neutrino beam. |last1=Agafonova |first1=N. |author2=et al. (OPERA Collaboration) |date=2010 |title=Observation of a first ντ candidate event in the OPERA experiment in the CNGS beam |journal=Physics Letters B |volume=691 |issue=3 |pages=138–145 |arxiv=1006.1623 |bibcode=2010PhLB..691..138A |doi=10.1016/j.physletb.2010.06.022 |s2cid=119256958 |date=6 June 2012 |title=OPERA Observes the Second Tau Neutrino |url=http://www.interactions.org/cms/?pid=1031794 |publisher=Istituto Nazionale di Fisica Nucleare |access-date=2012-06-08 |last=Jepsen |first=K. |date=26 March 2013 |title=OPERA snags third tau neutrino |url=http://www.symmetrymagazine.org/article/march-2013/opera-snags-third-tau-neutrino |work=Symmetry Magazine |access-date=2013-03-27 |last=O'Luanaigh|first=C. |date=6 October 2015 |title=OPERA detects its fifth tau neutrino |url=https://home.cern/about/updates/2015/06/opera-detects-its-fifth-tau-neutrino |access-date=2017-02-08
Time-of-flight measurements
Main article: Faster-than-light neutrino anomaly, Measurements of neutrino speed
In September 2011, OPERA researchers observed muon neutrinos apparently traveling faster than the speed of light. |last=Adam |first=T. |author2=et al. (OPERA collaboration) |date=17 November 2011 |title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam |class=hep-ex |eprint=1109.4897v1 |last=Brumfiel |first=G. |date=16 March 2012 |title=Neutrinos not faster than light |url=http://www.nature.com/news/neutrinos-not-faster-than-light-1.10249 |journal=Nature News |doi=10.1038/nature.2012.10249 |s2cid=119620081 |access-date=2013-03-12 |url-access=subscription |date = 8 June 2012 |title = Neutrinos sent from CERN to Gran Sasso respect the cosmic speed limit |url = http://press-archived.web.cern.ch/press-archived/PressReleases/Releases2011/PR19.11E.html |publisher = CERN |access-date = 2012-06-08 |url-status = dead |archive-url = https://web.archive.org/web/20140222165941/http://press-archived.web.cern.ch/press-archived/PressReleases/Releases2011/PR19.11E.html |archive-date = 22 February 2014 |last=Adam |first=T. |author2=et al. (OPERA collaboration) |date=2012 |title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam |journal=Journal of High Energy Physics |volume=2012 |issue= 10|page=93 |arxiv=1109.4897 |bibcode=2012JHEP...10..093A |doi=10.1007/JHEP10(2012)093 |s2cid=17652398 |last=Adam |first=T. |author2=et al. (OPERA collaboration) |date=2013 |title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam using the 2012 dedicated data |journal=Journal of High Energy Physics |volume=1 |article-number=153 |arxiv=1212.1276 |bibcode=2013JHEP...01..153A |doi=10.1007/JHEP01(2013)153 |s2cid=119258343
References
References
- (21 May 2018). "[OPERA]: News and Updates".
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