Editing Dark matter (section)

== Detection of dark matter particles ==
If dark matter is made up of subatomic particles, then millions, possibly billions, of such particles must pass through every square centimeter of the Earth each second.<ref name="Gaitskell 2004">{{cite journal |last=Gaitskell |first=Richard J. |s2cid=11316578 |title=Direct Detection of Dark Matter |journal=[[Annual Review of Nuclear and Particle Science]] |volume=54 |pages=315–359 |bibcode=2004ARNPS..54..315G |date=2004 |doi=10.1146/annurev.nucl.54.070103.181244|doi-access=free}}</ref><ref name="Number per second">{{cite web |title=Neutralino Dark Matter |url=http://www.picassoexperiment.ca/dm_neutralino.php |access-date=26 December 2011}}
{{cite web |title=WIMPs and MACHOs |url=http://www.astro.caltech.edu/~george/ay20/eaa-wimps-machos.pdf |archive-url=https://web.archive.org/web/20060923123531/http://www.astro.caltech.edu/~george/ay20/eaa-wimps-machos.pdf |archive-date=2006-09-23 |url-status=live |last=Griest |first=Kim |access-date=26 December 2011}}</ref> Many experiments aim to test this hypothesis. Although WIMPs have been the main search candidates,<ref name="bertone hooper silk" /> [[axion]]s have drawn renewed attention, with the [[Axion Dark Matter Experiment]] (ADMX) searches for axions and many more planned in the future.<ref name="Chadha-Day et al">{{cite journal |last1=Chadha-Day |first1=Francesca |last2=Ellis |first2=John |last3=Marsh |first3=David J. E. |date=23 February 2022 |title=Axion dark matter: What is it and why now? |journal=Science Advances |volume=8 |issue=8 |pages=eabj3618 |arxiv=2105.01406 |bibcode=2022SciA....8J3618C |doi=10.1126/sciadv.abj3618 |pmc=8865781 |pmid=35196098}}</ref> Another candidate is heavy [[hidden sector]] particles which only interact with ordinary matter via gravity.

These experiments can be divided into two classes: direct detection experiments, which search for the scattering of dark matter particles off atomic nuclei within a detector; and indirect detection, which look for the products of dark matter particle annihilations or decays.<ref name="bertone merritt" />

=== Direct detection ===
{{Further|Weakly interacting massive particle#Direct detection}}
{{Main|Direct detection of dark matter}}
Direct detection experiments aim to observe low-energy recoils of nuclei (typically a few [[keV]]) induced by interactions with particles of dark matter, which (in theory) are passing through the Earth. After such a recoil, the nucleus will emit energy in the form of [[scintillation (physics)|scintillation]] light or [[phonon]]s as they pass through sensitive detection apparatus. To do so effectively, it is crucial to maintain an extremely low background, which is the reason why such experiments typically operate deep underground, where interference from [[cosmic ray]]s is minimized. Examples of underground laboratories with direct detection experiments include the [[Stawell Underground Physics Laboratory|Stawell mine]], the [[Soudan mine]], the [[SNOLAB]] underground laboratory at [[Greater Sudbury|Sudbury]], the [[Gran Sasso National Laboratory]], the [[Canfranc Underground Laboratory]], the [[Boulby Underground Laboratory]], the [[Deep Underground Science and Engineering Laboratory]] and the [[China Jinping Underground Laboratory]].

These experiments mostly use either cryogenic or noble liquid detector technologies. Cryogenic detectors operating at temperatures below 100&nbsp;mK, detect the heat produced when a particle hits an atom in a crystal absorber such as [[germanium]]. [[Noble gas|Noble liquid]] detectors detect [[scintillation (physics)|scintillation]] produced by a particle collision in liquid [[xenon]] or [[argon]]. Cryogenic detector experiments include such projects as [[Cryogenic Dark Matter Search|CDMS]], [[Cryogenic Rare Event Search with Superconducting Thermometers|CRESST]], [[EDELWEISS]], and [[European Underground Rare Event Calorimeter Array|EURECA]], while noble liquid experiments include [[LZ experiment|LZ]], [[XENON]], [[DEAP]], [[ArDM]], [[WIMP Argon Programme|WARP]], [[DarkSide (dark matter experiment)|DarkSide]], [[PandaX]], and LUX, the [[Large Underground Xenon experiment]]. Both of these techniques focus strongly on their ability to distinguish background particles (which predominantly scatter off electrons) from dark matter particles (that scatter off nuclei). Other experiments include [[SIMPLE (dark matter)|SIMPLE]] and [[PICASSO (dark matter)|PICASSO]], which use alternative methods in their attempts to detect dark matter.

Currently there has been no well-established claim of dark matter detection from a direct detection experiment, leading instead to strong upper limits on the mass and interaction cross section with nucleons of such dark matter particles.<ref>{{cite journal |last1=Drees |first1=M. |last2=Gerbier |first2=G. |title=Dark Matter |journal=Chin. Phys. C |date=2015 |volume=38 |page=090001 |url=http://pdg.lbl.gov/2015/reviews/rpp2015-rev-dark-matter.pdf |archive-url=https://web.archive.org/web/20160722093442/http://pdg.lbl.gov/2015/reviews/rpp2015-rev-dark-matter.pdf |archive-date=2016-07-22 |url-status=live}}</ref> The [[DAMA/NaI]] and more recent [[DAMA/LIBRA]] experimental collaborations have detected an annual modulation in the rate of events in their detectors,<ref>{{cite journal |last1=Bernabei |first1=R. |last2=Belli |first2=P. |last3=Cappella |first3=F. |last4=Cerulli |first4=R. |last5=Dai |first5=C. J. |last6=d'Angelo |first6=A. |last7=He |first7=H. L. |last8=Incicchitti |first8=A. |last9=Kuang |first9=H. H. |last10=Ma |first10=J. M. |last11=Montecchia |first11=F. |last12=Nozzoli |first12=F. |last13=Prosperi |first13=D. |last14=Sheng |first14=X. D. |last15=Ye |first15=Z. P. |display-authors=6 |year=2008 |title=First results from DAMA/LIBRA and the combined results with DAMA/NaI |journal=Eur. Phys. J. C |volume=56 |issue=3 |pages=333–355 |arxiv=0804.2741 |bibcode=2008EPJC...56..333B |doi=10.1140/epjc/s10052-008-0662-y |s2cid=14354488}}</ref><ref>{{cite journal |doi=10.1103/PhysRevD.33.3495 |pmid=9956575 |author1=Drukier, A. |author2=Freese, K. |author3=Spergel, D. |title=Detecting Cold Dark Matter Candidates |journal=Physical Review D |volume=33 |issue=12 |pages=3495–3508 |date=1986 |bibcode=1986PhRvD..33.3495D}}</ref> which they claim is due to dark matter. This results from the expectation that as the Earth orbits the Sun, the velocity of the detector relative to the [[dark matter halo]] will vary by a small amount. This claim is so far unconfirmed and in contradiction with negative results from other experiments such as LUX, SuperCDMS<ref>{{cite journal |last1=Davis |first1=Jonathan H. |title=The past and future of light dark matter direct detection |journal=Int. J. Mod. Phys. A |year=2015 |volume=30 |issue=15 |page=1530038 |doi=10.1142/S0217751X15300380 |arxiv=1506.03924 |bibcode=2015IJMPA..3030038D |s2cid=119269304 }}</ref> and XENON100.<ref>{{cite journal |last1=Aprile |first1=E. |title=Search for electronic recoil event rate modulation with 4&nbsp;years of XENON100 data |journal=Phys. Rev. Lett. |year=2017 |volume=118 |issue=10 |page=101101 |doi=10.1103/PhysRevLett.118.101101 |pmid=28339273 |arxiv=1701.00769|bibcode=2017PhRvL.118j1101A |s2cid=206287497 }}</ref>

A special case of direct detection experiments covers those with directional sensitivity. This is a search strategy based on the motion of the Solar System around the [[Galactic Center]].<ref name="apssyn">{{cite news |last=Stonebraker |first=Alan |title=Synopsis: Dark-Matter Wind Sways through the Seasons |newspaper=Physics – Synopses |publisher=[[American Physical Society]] |date=3 January 2014 |doi=10.1103/PhysRevLett.112.011301 }}</ref><ref name="samlee">{{cite journal |last1=Lee |first1=Samuel K. |first2=Mariangela |last2=Lisanti |first3=Annika H.G.|last3=Peter |first4=Benjamin R.|last4=Safdi |doi=10.1103/PhysRevLett.112.011301 |arxiv=1308.1953 |title=Effect of Gravitational Focusing on Annual Modulation in Dark-Matter Direct-Detection Experiments |date=3 January 2014 |journal=Phys. Rev. Lett. |volume=112 |issue=1 |page=011301 [5 pages] |bibcode=2014PhRvL.112a1301L |pmid=24483881|s2cid=34109648 }}</ref><ref name="dmgsheff">{{cite news |last=The Dark Matter Group |title=An Introduction to Dark Matter |newspaper=Dark Matter Research |location=Sheffield |publisher=University of Sheffield |url=http://www.hep.shef.ac.uk/research/dm/intro.php |access-date=7 January 2014 |archive-date=29 July 2020 |archive-url=https://web.archive.org/web/20200729020742/http://www.hep.shef.ac.uk/research/dm/intro.php  }}</ref><ref name="Kavli">{{cite news |quote=Scientists at Kavli MIT are working on ... a tool to track the movement of dark matter. |title=Blowing in the Wind |newspaper=Kavli News |location=Sheffield |publisher=[[Kavli Foundation (United States)|Kavli Foundation]] |url=http://www.kavlifoundation.org/science-spotlights/blowing-wind |access-date=7 January 2014 |archive-date=7 October 2020 |archive-url=https://web.archive.org/web/20201007192326/http://www.kavlifoundation.org/science-spotlights/blowing-wind |url-status=dead }}</ref> A low-pressure [[time projection chamber]] makes it possible to access information on recoiling tracks and constrain WIMP-nucleus kinematics. WIMPs coming from the direction in which the Sun travels (approximately towards [[Cygnus (constellation)|Cygnus]]) may then be separated from background, which should be isotropic. Directional dark matter experiments include [[Dark Matter Time Projection Chamber|DMTPC]], [[Directional Recoil Identification From Tracks|DRIFT]], Newage and MIMAC.

=== Indirect detection ===
{{main|Indirect detection of dark matter}}
[[File:Collage of six cluster collisions with dark matter maps.jpg|thumb|upright=2|Collage of six cluster collisions with dark matter maps. The clusters were observed in a study of how dark matter in clusters of galaxies behaves when the clusters collide.<ref>{{cite web |title=Dark matter even darker than once thought |url=http://www.spacetelescope.org/news/heic1506/ |access-date=16 June 2015 |website=Space Telescope Science Institute}}</ref>]]
[[File:Turning Black Holes into Dark Matter Labs.webm|thumb|Video about the potential [[Gamma-ray astronomy|gamma-ray detection]] of dark matter [[annihilation]] around [[supermassive black hole]]s. ''(Duration 0:03:13, also see file description.)'']]
Indirect detection experiments search for the products of the self-annihilation or decay of dark matter particles in outer space. For example, in regions of high dark matter density (e.g., the [[Galactic Center|centre of the Milky Way]]) two dark matter particles could [[Annihilation|annihilate]] to produce [[gamma ray]]s or Standard Model particle–antiparticle pairs.<ref name="Bertone2010">{{cite book |first=Gianfranco |last=Bertone |title=Particle Dark Matter: Observations, Models and Searches |chapter-url=https://books.google.com/books?id=JkUgAwAAQBAJ&pg=PA83 |year=2010 |publisher=Cambridge University Press |pages=83–104 |chapter=Dark Matter at the Centers of Galaxies |arxiv=1001.3706 |isbn=978-0-521-76368-4 |bibcode=2010arXiv1001.3706M}}</ref> Alternatively, if a dark matter particle is unstable, it could decay into Standard Model (or other) particles. These processes could be detected indirectly through an excess of gamma rays, [[antiproton]]s or [[positron]]s emanating from high density regions in the Milky Way and other galaxies.<ref>{{cite journal |last1=Ellis |first1=J. |last2=Flores |first2=R. A. |last3=Freese |first3=K. |last4=Ritz |first4=S. |last5=Seckel |first5=D. |last6=Silk |first6=J. |year=1988 |title=Cosmic ray constraints on the annihilations of relic particles in the galactic halo |url=https://cds.cern.ch/record/190709/files/198809398.pdf |url-status=live |journal=Physics Letters B |volume=214 |issue=3 |pages=403–412 |bibcode=1988PhLB..214..403E |doi=10.1016/0370-2693(88)91385-8 |archive-url=https://web.archive.org/web/20180728133226/https://cds.cern.ch/record/190709/files/198809398.pdf |archive-date=2018-07-28}}</ref> A major difficulty inherent in such searches is that various astrophysical sources can mimic the signal expected from dark matter, and so multiple signals are likely required for a conclusive discovery.<ref name="bertone hooper silk" /><ref name="bertone merritt" />

A few of the dark matter particles passing through the Sun or Earth may scatter off atoms and lose energy. Thus dark matter may accumulate at the center of these bodies, increasing the chance of collision/annihilation. This could produce a distinctive signal in the form of high-energy [[neutrino]]s.<ref>{{cite journal |doi=10.1016/0370-2693(86)90349-7 |author=Freese, K. |title=Can Scalar Neutrinos or Massive Dirac Neutrinos be the Missing Mass? |journal=Physics Letters B |volume=167 |issue=3 |pages=295–300 |date=1986 |bibcode=1986PhLB..167..295F}}</ref> Such a signal would be strong indirect proof of WIMP dark matter.<ref name="bertone hooper silk" /> High-energy neutrino telescopes such as [[Antarctic Muon And Neutrino Detector Array|AMANDA]], [[IceCube]] and [[ANTARES (telescope)|ANTARES]] are searching for this signal.<ref name=Randall_2015>
{{cite book
 |first=Lisa |last=Randall
 |year=2015
 |title=Dark Matter and the Dinosaurs: The astounding interconnectedness of the Universe
 |publisher=Ecco / HarperCollins Publishers
 |location=New York, NY
 |isbn=978-0-06-232847-2
}}</ref>{{rp|298}} The detection by [[LIGO]] in [[GW150914|September 2015]] of gravitational waves opens the possibility of observing dark matter in a new way, particularly if it is in the form of [[primordial black hole]]s.<ref>{{cite magazine |url=https://www.newscientist.com/article/2077800-what-will-gravitational-waves-tell-us-about-the-universe |title=Surfing gravity's waves |magazine=New Scientist |first=Joshua |last=Sokol |display-authors=etal |issue=3061 |date=20 February 2016}}</ref><ref>{{cite web |publisher=Johns Hopkins University |title=Did gravitational wave detector find dark matter? |date=15 June 2016 |url=http://releases.jhu.edu/2016/06/15/did-gravitational-wave-detector-find-dark-matter/ |access-date=20 June 2015 |quote=While their existence has not been established with certainty, primordial black holes have in the past been suggested as a possible solution to the dark matter mystery. Because there is so little evidence of them, though, the primordial black hole–dark matter hypothesis has not gained a large following among scientists. The LIGO findings, however, raise the prospect anew, especially as the objects detected in that experiment conform to the mass predicted for dark matter. Predictions made by scientists in the past held conditions at the birth of the universe would produce many of these primordial black holes distributed approximately evenly in the universe, clustering in halos around galaxies. All this would make them good candidates for dark matter.}}</ref><ref>{{cite journal |last1=Bird |first1=Simeon |last2=Cholis |first2=Illian |year=2016 |title=Did LIGO detect dark matter? |journal=Physical Review Letters |volume=116 |issue=20 |page=201301 |doi=10.1103/PhysRevLett.116.201301 |pmid=27258861 |bibcode=2016PhRvL.116t1301B |arxiv=1603.00464|s2cid=23710177 }}</ref>

Many experimental searches have been undertaken to look for such emission from dark matter annihilation or decay, examples of which follow.

The [[Energetic Gamma Ray Experiment Telescope]] observed more gamma rays in 2008 than expected from the [[Milky Way]], but scientists concluded this was most likely due to incorrect estimation of the telescope's sensitivity.<ref>{{cite journal |last1=Stecker |first1=F. W. |last2=Hunter |first2=S. |last3=Kniffen |first3=D. |year=2008 |title=The likely cause of the EGRET GeV anomaly and its implications |journal=Astroparticle Physics |volume=29 |issue=1 |pages=25–29 |arxiv=0705.4311 |bibcode=2008APh....29...25S |doi=10.1016/j.astropartphys.2007.11.002 |s2cid=15107441}}</ref>

The [[Fermi Gamma-ray Space Telescope]] is searching for similar gamma rays.<ref>{{cite journal |title=The large area telescope on the Fermi Gamma-ray Space Telescope Mission |journal=Astrophysical Journal |volume=697 |issue=2 |year=2009 |pages=1071–1102 |doi=10.1088/0004-637X/697/2/1071 |arxiv=0902.1089 |first1=W.B. |last1=Atwood |last2=Abdo |first2=A.A. |last3=Ackermann |first3=M. |last4=Althouse |first4=W. |last5=Anderson |first5=B. |last6=Axelsson |first6=M. |last7=Baldini |first7=L. |last8=Ballet |first8=J. |last9=Band |first9=D.L. |display-authors=6 |bibcode=2009ApJ...697.1071A|s2cid=26361978 }}</ref> In 2009, an as yet unexplained surplus of gamma rays from the Milky Way's galactic center was found in Fermi data. This [[Galactic Center GeV excess]] might be due to dark matter annihilation or to a population of pulsars.<ref>{{cite web |date=2019-11-12 |title=Physicists revive hunt for dark matter in the heart of the Milky Way |url=https://www.science.org/content/article/physicists-revive-hunt-dark-matter-heart-milky-way |access-date=2023-05-09 |website=www.science.org |language=en}}</ref> In April 2012, an analysis of previously available data from Fermi's [[Fermi LAT|Large Area Telescope]] instrument produced statistical evidence of a 130&nbsp;GeV signal in the gamma radiation coming from the center of the Milky Way.<ref>{{cite journal |doi=10.1088/1475-7516/2012/08/007 |last=Weniger |first=Christoph |title=A tentative gamma-ray line from dark matter annihilation at the Fermi Large Area Telescope |journal=Journal of Cosmology and Astroparticle Physics |issue=8 |date=2012 |arxiv=1204.2797 |volume=2012 |page=7 |bibcode=2012JCAP...08..007W|s2cid=119229841 }}</ref> WIMP annihilation was seen as the most probable explanation.<ref>{{cite web |url=http://physicsworld.com/cws/article/news/2012/apr/24/gamma-rays-hint-at-dark-matter |title=Gamma rays hint at dark matter |last1=Cartlidge |first1=Edwin |date=24 April 2012 |publisher=Institute of Physics |access-date=23 April 2013}}</ref>

At higher energies, [[IACT|ground-based gamma-ray telescopes]] have set limits on the annihilation of dark matter in [[dwarf spheroidal galaxy|dwarf spheroidal galaxies]]<ref>{{Cite journal |last1=Albert |first1=J. |last2=Aliu |first2=E. |last3=Anderhub |first3=H. |last4=Antoranz |first4=P. |last5=Backes |first5=M. |last6=Baixeras |first6=C. |last7=Barrio |first7=J.A. |last8=Bartko |first8=H. |last9=Bastieri |first9=D. |last10=Becker |first10=J.K. |last11=Bednarek |first11=W. |last12=Berger |first12=K. |last13=Bigongiari |first13=C. |last14=Biland |first14=A. |last15=Bock |first15=R.K. |last16=Bordas |first16=P. |last17=Bosch-Ramon |first17=V. |last18=Bretz |first18=T. |last19=Britvitch |first19=I. |last20=Camara |first20=M. |last21=Carmona |first21=E. |last22=Chilingarian |first22=A. |last23=Commichau |first23=S. |last24=Contreras |first24=J.L. |last25=Cortina |first25=J. |last26=Costado |first26=M.T. |last27=Curtef |first27=V. |last28=Danielyan |first28=V. |last29=Dazzi |first29=F. |last30=De Angelis |first30=A. |display-authors=6 |title=Upper Limit for γ-Ray Emission above 140&nbsp;GeV from the Dwarf Spheroidal Galaxy Draco |doi=10.1086/529135 |journal=The Astrophysical Journal |volume=679 |issue=1 |pages=428–431 |year=2008 |arxiv=0711.2574 |bibcode=2008ApJ...679..428A|s2cid=15324383 }}</ref> and in clusters of galaxies.<ref>{{cite journal |last1=Aleksić |first1=J. |last2=Antonelli |first2=L.A. |last3=Antoranz |first3=P. |last4=Backes |first4=M. |last5=Baixeras |first5=C. |last6=Balestra |first6=S. |last7=Barrio |first7=J.A. |last8=Bastieri |first8=D. |last9=González |first9=J.B. |last10=Bednarek |first10=W. |last11=Berdyugin |first11=A. |last12=Berger |first12=K. |last13=Bernardini |first13=E. |last14=Biland |first14=A. |last15=Bock |first15=R.K. |last16=Bonnoli |first16=G. |last17=Bordas |first17=P. |last18=Tridon |first18=D.B. |last19=Bosch-Ramon |first19=V. |last20=Bose |first20=D. |last21=Braun |first21=I. |last22=Bretz |first22=T. |last23=Britzger |first23=D. |last24=Camara |first24=M. |last25=Carmona |first25=E. |last26=Carosi |first26=A. |last27=Colin |first27=P. |last28=Commichau |first28=S. |last29=Contreras |first29=J.L. |last30=Cortina |first30=J. |display-authors=6 |title=Magic Gamma-Ray Telescope observation of the Perseus Cluster of galaxies: Implications for cosmic rays, dark matter, and NGC&nbsp;1275 |doi=10.1088/0004-637X/710/1/634 |journal=The Astrophysical Journal |volume=710 |issue=1 |pages=634–647 |year=2010 |arxiv=0909.3267 |bibcode=2010ApJ...710..634A|s2cid=53120203 }}</ref>

The [[Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics|PAMELA]] experiment (launched in 2006) detected excess [[positron]]s. They could be from dark matter annihilation or from [[pulsar]]s. No excess [[antiproton]]s were observed.<ref>{{cite journal |last1=Adriani |first1=O. |last2=Barbarino |first2=G.C. |last3=Bazilevskaya |first3=G.A. |last4=Bellotti |first4=R. |last5=Boezio |first5=M. |last6=Bogomolov |first6=E.A. |last7=Bonechi |first7=L. |last8=Bongi |first8=M. |last9=Bonvicini |first9=V. |last10=Bottai |doi=10.1038/nature07942 |first10=S. |last11=Bruno |first11=A. |last12=Cafagna |first12=F. |last13=Campana |first13=D. |last14=Carlson |first14=P. |last15=Casolino |first15=M. |last16=Castellini |first16=G. |last17=De Pascale |first17=M.P. |last18=De Rosa |first18=G. |last19=De Simone |first19=N. |last20=Di Felice |first20=V. |last21=Galper |first21=A.M. |last22=Grishantseva |first22=L. |last23=Hofverberg |first23=P. |last24=Koldashov |first24=S.V. |last25=Krutkov |first25=S.Y. |last26=Kvashnin |first26=A.N. |last27=Leonov |first27=A. |last28=Malvezzi |first28=V. |last29=Marcelli |first29=L. |last30=Menn |first30=W. |display-authors=6 |title=An anomalous positron abundance in cosmic rays with energies 1.5–100&nbsp;GeV |journal=Nature |volume=458 |issue=7238 |pages=607–609 |year=2009 |pmid=19340076 |arxiv=0810.4995 |bibcode=2009Natur.458..607A|s2cid=11675154 }}</ref>

In 2013, results from the [[Alpha Magnetic Spectrometer]] on the [[International Space Station]] indicated excess high-energy [[cosmic ray]]s which could be due to dark matter annihilation.<ref name="APS-20130403">{{cite journal |title=First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–350&nbsp;GeV |date=3 April 2013 |journal=[[Physical Review Letters]] |author=Aguilar, M. |collaboration=AMS Collaboration |doi=10.1103/PhysRevLett.110.141102 |bibcode=2013PhRvL.110n1102A |display-authors=etal |volume=110 |issue=14 |pmid=25166975 |page=141102|doi-access=free |hdl=1721.1/81241 |hdl-access=free }}</ref><ref name="AMS-20130403">{{cite web |title=First Result from the Alpha Magnetic Spectrometer Experiment |url=http://www.ams02.org/2013/04/first-results-from-the-alpha-magnetic-spectrometer-ams-experiment/ |date=3 April 2013 |author=AMS Collaboration |access-date=3 April 2013 |archive-url=https://web.archive.org/web/20130408185229/http://www.ams02.org/2013/04/first-results-from-the-alpha-magnetic-spectrometer-ams-experiment/ |archive-date=8 April 2013  }}</ref><ref name="AP-20130403">{{cite news |last1=Heilprin |first1=John |last2=Borenstein |first2=Seth |title=Scientists find hint of dark matter from cosmos |url=http://apnews.excite.com/article/20130403/DA5E6JAG3.html |date=3 April 2013 |agency=Associated Press |access-date=3 April 2013}}</ref><ref name="BBC-20130403">{{cite news |last=Amos |first=Jonathan |title=Alpha Magnetic Spectrometer zeroes in on dark matter |url=https://www.bbc.co.uk/news/science-environment-22016504 |date=3 April 2013 |work=BBC |access-date=3 April 2013}}</ref><ref name="NASA-20130403">{{cite web |last1=Perrotto |first1=Trent J. |last2=Byerly |first2=Josh |title=NASA TV Briefing Discusses Alpha Magnetic Spectrometer Results |url=http://www.nasa.gov/home/hqnews/2013/apr/HQ_M13-054_AMS_Findings_Briefing.html |date=2 April 2013 |website=NASA |access-date=3 April 2013}}</ref><ref name="NYT-20130403">{{cite news |last=Overbye |first=Dennis |title=New Clues to the Mystery of Dark Matter |url=https://www.nytimes.com/2013/04/04/science/space/new-clues-to-the-mystery-of-dark-matter.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2013/04/04/science/space/new-clues-to-the-mystery-of-dark-matter.html |archive-date=2022-01-01 |url-access=limited |date=3 April 2013 |work=The New York Times |access-date=3 April 2013}}{{cbignore}}</ref>

=== Collider searches for dark matter ===
An alternative approach to the detection of dark matter particles in nature is to produce them in a laboratory. Experiments with the [[Large Hadron Collider]] (LHC) may be able to detect dark matter particles produced in collisions of the LHC [[proton]] beams. Because a dark matter particle should have negligible interactions with normal visible matter, it may be detected indirectly as (large amounts of) missing energy and momentum that escape the detectors, provided other (non-negligible) collision products are detected.<ref name="kane watson">{{cite journal |author1=Kane, G. |author2=Watson, S. |title=Dark Matter and LHC:. what is the Connection? |journal=Modern Physics Letters A |year=2008 |volume=23 |pages=2103–2123 |doi=10.1142/S0217732308028314 |bibcode=2008MPLA...23.2103K |arxiv=0807.2244 |issue=26|s2cid=119286980 }}</ref> Constraints on dark matter also exist from the [[Large Electron–Positron Collider|LEP]] experiment using a similar principle, but probing the interaction of dark matter particles with electrons rather than quarks.<ref>{{cite journal |last1=Fox |first1=P. J. |last2=Harnik |first2=R. |last3=Kopp |first3=J. |last4=Tsai |first4=Y. |year=2011 |title=LEP Shines Light on Dark Matter |journal=Phys. Rev. D |volume=84 |issue=1 |page=014028 |arxiv=1103.0240 |bibcode=2011PhRvD..84a4028F |doi=10.1103/PhysRevD.84.014028 |s2cid=119226535}}</ref> Any discovery from collider searches must be corroborated by discoveries in the indirect or direct detection sectors to prove that the particle discovered is, in fact, dark matter.