Experiments on Neutrinos

Are listed here the main experiments (mainly post-1980) mentioned in those web pages. We aim at pointing out experiments which had a major historical impact on the neutrino experimental studies after 1980. You will find here only a few lines about the aim and the results of each experiment. More information can be found from the links provided below (experiment link or wikipedia link), or from the Wikipedia list of neutrino experiments or from the quite exhaustive list available on the Maury Goodman’s web site http://www.hep.anl.gov/ndk/hypertext/

  1. Neutrinos from nuclear reactors
  2. Neutrinos from particle accelerators
  3. Neutrinos from the sky ,the Sun, the stars
  4. Other experiments that contributed to neutrino knowledge

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Neutrinos from nuclear reactors

  • 1956 The Neutrino discovery experiment : This is the experiment of F. Reines and C. Cowan at the Savannah River nuclear power plant that confirmed the hint observed by their 1953 Poltergeist project at the Hanford nuclear power plant. The detector was at 11 m from the reactor and 12 m underground. It was made of two compartments containing 200 liters of water with cadmium chloride and organic liquid scintillators. The two compartments were sandwiched by three layers of photomultipliers. This experiment main result was the first evidence of neutrino (in fact electron-antineutrino νe) interactions and marked thus the discovery of the neutrino. [Wikipedia link]
  • 1984-1996 Bugey : This experiment was based on the same detection principle as the 1956 experiment. It was at the same time as ILL Grenoble and Gösgen (Switzerland) neutrino experiments. It was running at different distances from the Bugey nuclear reactor (close to Lyon) and provided, along with Gösgen, the first constraints on the νeνμ oscillation parameters. Last results were obtained with the Bugey 3 experiment in 1996.
  • 1989-1999 Palo Verde : to be filled [Wikipedia link]
  • 1984-1990 ILL: to be filled  [Wikipedia link]
  • 1995-1999 Chooz : This detector was located in France, 1 km from Chooz nuclear plant and about 100 meters underground, in an old tunnel. It was made of 300 liters of liquid scintillator doped with gadolinium, in a transparent acrylic target vessel srrounded by photomultipliers. This target was surrounded by a bigger vessel with photomultipliers allowing to eliminate the background due to cosmic rays or natural radioactivity. In 1999, Chooz gave as last result a limit on neutrino oscillation parameters: sin2(2θ13) < 0.17 for large Δm2 and Δm2 > 8×10−4 eV2 for maximal mixing. [Wikipedia link]
  • 2009-2017 Double Chooz : This experiment is in the continuity of the Chooz experiment. It was proposed in 2003 and has been installed in 2009 near the Chooz nuclear power plant. Its main result has been published in 2011 and was the first hint for the non-zero value of θ13 mixing angle in reactor experiments. [Wikipedia link]
  • 2011-2015 Daya Bay : This international neutrino experiment is located at Daya Bay, 50 km north-east Hong Kong. It is made of 8 anti-neutrino detectors, clustered in three locations close to six nuclear reactors. Each detector is 20 tons of liquid scintillator surrounded by photomultipliers. This experiment provided in March 2012 the best estimation of the θ13 neutrino oscillation mixing angle.  This result was updated in 2014: sin2(2θ13) = 0.090 +-0.008 . [Wikipedia link]
  • 2011 RENO: This is a short baseline reactor neutrino oscillation experiment in South Korea, designed to measure the neutrino oscillation mixing angle θ13. RENO has two identical detectors, placed at distances of 294 m and 1383 m, that observe electron antineutrinos produced by six reactors of the Hanbit Nuclear Power Plant. Each detector consists of 16.5 t of gadolinium-doped liquid scintillator surrounded by 450 tons of buffer, veto and shielding liquids. In April 2012, its results confirmed the measurement of θ13 published by the Daya Bay experiment. [Wikipedia link]

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Neutrinos from particle accelerators

  • 1962 Muon-neutrino discovery : This experiment, proposed by M. Schwartz, L. Lederman and J. Steinberger in 1962, used a neutrino beam coming from the decay of pions produced thanks to the BNL (Brookhaven National Laboratory) 15 GeV proton beam of the AGS slamming into a beryllium target. Those neutrinos were detected by a 10-ton spark chamber consisting of 90 aluminum plates separated by gas-filled gaps. Any neutrino interaction with the gas produces charged particles, electron or muon, whichd ionize the gas and create visible spark track when high voltages were applied across the plates.
    During several months of experimental runs, an estimated 3.48×1017 protons hit the beryllium target. Out of this assault, the detector yielded just 113 events that met the experimenters’ criteria as potential neutrinos. Among them, 51 events were identified as triggered by high-energy neutrinos of the beam. All of them were long tracks identified as muons. The conclusion was that the 51 neutrinos of the beam were “likely different from the neutrinos involved in beta decay”. This was the discovery of the muon neutrino, which was already predicted for theoretical reasons based on the fact that no muon decay producing a photon had been observed. [Wikipedia link]
  • 1976-1984 CDHS : to be filled [Wikipedia link]
  • 1976 HPWF : to be filled [Wikipedia link]
  • 1971-1979 Gargamelle : It was a heavy liquid bubble chamber detector located at CERN and designed to detect neutrinos produced thanks to the Proton Synchrotron and later thanks to the Super Proton Synchrotron (SPS). Under the responsability of Andre Lagarrigue, the Gargamelle chamber provided hints of the existence of quarks by looking at inelastic scattering of neutrinos by nucleii and later allowed to discover the neutral currents in July 1973. Those were neutrino interactions without flavor change and were the first experimental indication of the existence of the Z0 boson predicted by the electroweak theory. The Gargamelle chamber was entirely constructed at Saclay and assembled at CERN. It was 4.8 meters long and 2 meters in diameter, and contained 12 cubic meters of heavy liquid Freon, whose temperature was regulated by water tubes. It was surrounded by a magnet providing a 2 Tesla field and various optics for illumination and for taking photographs of the particle tracks. [Wikipedia link]
  • 1973-1984 BEBC (Big European Bubble Chamber) :  This detector, based at CERN, was a large bubble chamber filled with 35 m3 of superheated liquid hydrogen, liquid deuterium or a neon-hydrogen mixture, operated around 27 K and 5 atm, and surrounded by  a large superconducting solenoid providing a 3.5 Tesla magnetic field. The particle bubbles tracks were photographed by five cameras mounted on top of the chamber that provided millions of stereo photographs subsequently scanned for various experiments.
    The project started in 1966 and the first images were recorded in 1973.  From 1977 to 1984, the chamber operated in the West Area neutrino beam line of the Super Proton Synchrotron (SPS) and promoted, among others, several intersting physics results about neutrino and weak interaction. [Wikipedia link]
  • 1973-1988 The 15-foot bubble chamber : When it recorded its first track in September 1973, it was the largest liquid hydrogen bubble chamber in the world. Built at Fermilab it provided various results for neutrino physics or for particle physics using neutrino beams. It was a spherical chamber about 5 meters diameter filled with a liquid mix of neon and hydrogen in pressure and temperature conditions that allowed bubbles to form along the track of charged particles. [Wikipedia link] [Other link]
  • 1997-2000 DONUT : It was an experiment located at Fermilab and dedicated to the search for tau neutrino interactions. The detector operated during a few months in the summer of 1997: protons from the Tevatron were used to produce tau neutrinos via decay of charmed mesons. Magnets, iron shield and several sheets of nuclear emulsion followed by scintillators and drift chambers were used to identify tau-neutrino interactions. After analysis of tracks in the emulsion, the DONUT collaboration announced in July 2000 the first observation of tau neutrino interactions. [Wikipedia link]
  • 1995-1998 NOMAD : The NOMAD detector (or WA96) was located at CERN and was searching for ντ in a νμ beam produced thanks to the protons of the SPS. The detector was made of several parts (drift chambers, TRD, preshower and electromagnetic calorimeter) that allowed to identify strongly the electrons coming from the tau produced by a ντ interaction. The mean energy of the beam was around 27 GeV and the mean distance for neutrino oscillation was 650 m. This choice was guided by a theoretical conjecture that the ντ mass might be the main component of dark matter. NOMAD found no oscillations. In 2018, the knowledge about neutrino oscillation parameters allow to conclude that the mean distance that NOMAD should have used is about 1000 km. [no Wikipedia link]
  • 1997 CHORUS : The CHORUS detector was located at CERN, near the NOMAD detector. It was looking also for ντ interactions but only mainly photographic emulsion to track the tau interaction. [no Wikipedia link]
  • 1993-1998 LSND : The Liquid Scintillator Neutrino Detector (LSND) was located at Los Alamos National Laboratory and was looking for νe or νe in a νμ or νμ neutrino beam produced by the LAMPF facility. The detector was a tank filled with 167 tons of mineral oil and 6.4 kg of organic scintillator, surrounded by 1220 photomultipliers. Its results indicated neutrino oscillation which, taken within the standard model with three neutrino flavors, were in conflict with other solar and atmospheric neutrino results. Cosmological constrain on the mass of the neutrinos later excluded the sterile neutrino hypothesis as an explanation of this LSND anomaly. [Wikipedia link]
  • 2001 KamLAND :  This electron antineutrino detector is located underground in the Kamioka mine, near Toyama, Japan, which is a site surrounded by many nuclear reactors producing electron antineutrinos. The detector was composed of 1879 photomultipliers inside a 18 meter-diameter vessel and surrounding an inner 13 m-diameter nylon balloon filled with 1000 m3 of liquid scintillator. In addition, a 3.2 kiloton cylindrical water Cherenkov detector surrounded the vessel. KamLAND data taking started in 2002 and first results showed neutrino oscillation. In 2008, combining KamLAND results and solar neutrino results, the most precise determination of oscillation parameter was provided: Δm122 =( 7.59 +- 0.21) .10-5 eV and tan2(θ12) = 0.47 +- 0.06
    In 2013, looking for Geo-neutrinos, and combinng its result with those of Borexino, constrained the Uranium/Thorium natural radioactive heat power of the Earth to be lower than 19.1 TW. [Wikipedia link]
  • 2005 and 2016 MINOSThis long-baseline neutrino experiment was designed to observe neutrino oscillations. It was made of two detectors, one located at Fermilab, at the source of the neutrinos, and the other located 800 km away, in northern Minnesota, at the Soudan Underground Mine. It received the Numi neutrino beam until 2012 and published in 2013 a measurement of the neutrino mixing angle θ23 and, thanks to anti-neutrino beam, a measurement of θ13. An upgrade, MINOS+, was operated from 2013 to 2016. [Wikipedia link]
  • 2008-2014 OPERA (Oscillation Project with Emulsion tRacking Apparatus): This long baseline neutrino experiment, installed at the Gran Sasso underground laboratory, was built from 2003 to 2008. It received the CNGS νμ neutrino beam provided by CERN, 730 km away. It was made of two supermodules containing 150000 bricks (photographic emulsion interleaved with lead sheets) interleaved with plastic scintillator counters. Each supermodule was followed by a magnetic spectrometer. Real time tagging by the scintillators and spectrometers and development and scanning of the bricks allowed to identify the tau resulting from the interaction of tau neutrinos. First ντ was observed in May 2010. [Wikipedia link]
  • 2016-2018 NOvA : The NOvA (NuMI Off-axis νe Appearance) experiment studies the neutrino oscillation properties. The detector (14 ktons located in Ash River, Minnesota) receives the Numi neutrino beam generated at Fermilab, 735 km away. It is completed by a near detector located at Fermilab, which statistically gets the neutrinos type before their travel. [Wikipedia link]
  • 2010-2018 MINERvA : It is a neutrino scattering experiment which uses the NuMI beamline at Fermilab. MINERνA study low energy neutrino interactions both in support of neutrino oscillation experiments and the strong dynamics of the nucleon and nucleus that affect these interactions. It was proposed in 2004 and the detector was installed in 2010. It is made of many layers of parallel scintillator strips connected to photomultipliers. [Wikipedia link]
  • 2009-2018 T2K (and K2K) : a long baseline neutrino oscillation experiment in Japan that uses a muon neutrino beam produced by J-PARC and propagating through 295 km to the Super-Kamiokande water Cherenkov detector. It is a off-axis experiment and it receives also anti-neutrinos since 2014. [Wikipedia link].
    Its predecessor was K2K, which ran from June 1999 to November 2004. It found oscillation parameters which were consistent with those measured by Super-Kamiokande using atmospheric neutrinos. It was made of a 1-kiloton water Cherenkov neutrino detector (“near detector”) located at about 300 m from the neutrino production and the 50-kiloton Super-Kamiokande “far detector” located at the Kamioka Observatory, The νμ disappearance observed by K2K provided a determination of oscillation parameters in good agreement with the previous Super-Kamiokande result and the later MINOS result. [Wikipedia link]

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Neutrinos from the sky, the sun, the stars

  • 1965 Kolar Gold and South Africa experiments : Located in India, in the Kolar Gold Field mine, 7500 m underground, the KGF detector was looking for muons produced by atmospheric neutrinos, resulting from cosmic rays interaction with Earth’s atmosphere. It was made of 3m walls of plastic scintillators, Neon flash tubes and photomultipliers. The experiment discovered the first atmospheric neutrinos about the same time as an other experiment done by F. Reines team in a mine in South Africa. Some of the experimental observations, called Kolar events, have yet to be explained as they suggested the existence of massive particles having a long life time and that interacted with the detector. [Wikipedia link]
  • 1968-1994 Homestake Chlorine Experiment :
    Argon Extraction System of the Homestake experiment
    First setup of the Homestake experiment

    This experiment proposed by Raymond Davis, Jr. and John N. Bahcall in 1968, was trying to observe neutrinos emitted by nuclear reactions inside the Sun. It was located in Homestake Gold Mine, South Dakota, 1478 m underground. The detector was made of a 380 m3 tank of perchloroethylene. Upon interaction with an electron neutrino above 0.814 MeV, a chlorine-37 atom transforms into a radioactive isotope of argon-37, which can then be extracted and counted. Every few weeks, Davis bubbled helium through the tank to collect the argon that had formed. A few cm3 gas counter was filled by the collected few tens of atoms of argon-37 (together with the stable argon) to detect its decays and, thus, to determine how many neutrinos had been detected.
    J. Bahcall did the theoretical calculations and R. Davis designed the experiment. The first result, in 1969, was that the rate of detected neutrinos was 1/3 of the theoretical rate computed by Bahcall. The experiment operated continuously from 1970 until 1994, always confirming this discrepancy, which later turned out to be due to neutrino oscillation. [Wikipedia link]

  • 1982-1989 IMB : The Irvine-Michigan-Brookhaven experiment (IMB) was a nucleon decay experiment and neutrino observatory located underground near the Lake Erie in USA. The detector was built primarily with the goal of observing proton decay, but it achieved neutrino observation, particularly those from the supernova SN1987A.
    The detetor was a tank about 17 × 17.5 × 23 meters, filled with 9460 cubic meters of ultrapure water surrounded by 2048 photomultiplier. The detection of Cerenkov light produced by fast-moving particles produced by proton decay or neutrino interactions allowed also to estimate the initial direction of the neutrinos. [Wikipedia link]
  • 1982-1987 Kamiokande : The Kamioka Nucleon Decay Experiment was a detector located underground in the Kamioka mine, in Japan. It was a large cylindrical tank containing 3000 tons of pure water and about 1000 photomultipliers looking for Cerenkov light emitted by high velocity particles. Designed to search for proton decay, it was also used to detect neutrino interaction events. Kamiokande II was operational from 1985 to 1987 and was one of the neutrino detectors which registered a few of the neutrinos produced by the supernova SN1987A. It was also used to provide hint about the solar neutrinos deficit and the atmospheric neutrinos deficit. Its successor, SuperKamiokande, provided in 1998 the first strong evidence of neutrino oscillations. [Wikipedia link]
  • 1984-1988 Fréjus : Between 1984 and 1988, a detector located in the LSM (Laboratoire Soutterrain de Modane), in the Frejus tunnel and initially dedicated to nucleon-decay search, has been used to study atmospheric neutrino oscillation. No oscillation has been observed but some constraint have been put on the oscillation parameters, similar to the first constraint obtained by the Bugey and Gosgen neutrino experiments.  [Wikipedia link]
  • Baksan : to be filled  [Wikipedia link]
  • Nusex : to be filled  [Wikipedia link]
  • 1991-1997 GALLEX : This experiment was located underground at the Gran Sasso laboratory (LNGS). It was a radiochemical solar neutrino detector able to look for the first time to low energy solar neutrinos. It was made a 54 cubic meters tank filled with 101 tons of gallium trichloride-hydrochloric acid solution, which contained 30.3 tons of gallium. Down to 233 keV, neutrinos could interact with the Gallium to produce Germanium whose radioactive decay could then be detected after its extraction. Each detected decay corresponded to one detected neutrino and the final result was a confirmation of the solar neutrino deficit observed by Davis and a confirmation of the solar model elaborated by Bahcall. [Wikipedia link]
  • 1990-2010 SAGE : A Russian-american Gallium detector similar to GALLEX [Wikipedia link]
  • 1996-2018 SuperKamiokande : This detector was located 1000 m underground in the Mozumi Mine in Hida’s Kamioka area, Japan. This location has been extended to become the Kamioka observatory. It was designed to detect high-energy solar or atmospheric neutrinos, to search for proton decay or alert for galactic supernovae. It is mainly composed of a cylindrical tank containing 50 ktons of ultrapure water and a set of 13000 photomultipliers to detect Cerenkov light emitted by particles coming from neutrino interactions. The experiment, succesor of Kamiokande detector, operated from April 1996 to July 2001. After an accident and a half-operational phase, the experiment resumed in July 2006.One of the main result of SuperKamiokande was in 1998 the observational evidence of neutrino oscillation , with oscillation parameters that confirmed the suspected oscillation of the solar neutrinos. [Wikipedia link]
  • 1999-2006 SNO (Sudbury Neutrino Observatory) : This detector is located 2100 m underground in the Creighton Mine in Sudbury, Ontario, Canada. Designed to detect solar neutrinos, this experiment was first proposed in 1984 by Herb Chen, approved in 1990 and operated from May 1999 to December 2006.  The SNO detector was a 12 m spherical vessel of 1000 m3 of heavy water surrounded by 9600 photomultipliers. It was able to see the solar νe charged current interaction but also the three neutrino types neutral current interactions. This allowed the SNO experiment to provide in 2001 the unambiguous proof of the solar neutrino oscillation over a large energy range. In 2009, its underground location has been enlarged into the SNOLAB permanent facility to operate various other experiments. [Wikipedia link]
  • 1992-2006 LVD (Large Volume Detector) : This neutrino detector was located in the Gran Sasso laboratory and was dedicated to the detection of neutrinos from supernovae. It has been in operation since June 1992, without detecting any event, and is a member of the Supernova Early Warning System since July 2005. It uses 840 scintillator counters around a large tank of hydrocarbons that allows to detect both charged current and neutral current interactions. [Wikipedia link].
  • 2011 AMANDA : to be filled  [Wikipedia link]
  • 2013 ANTARES : This experiment aimed at detecting high energy neutrinos using the water of the Mediterraneen sea and lines of photomultipliers detecting Cerenkov light.  [Wikipedia link]
    Publications: http://antares.in2p3.fr/Publications
  • 2003-2015 Baïkal (or BDUNT): Since 2003, the Baikal Deep Underwater Neutrino Telescope (BDUNT) neutrino detector is located 1200 m below the surface of the Lake Baikal. The first detector, NT-200, was started in 1990, completed in 1998 and upgraded in 2005. BDUNT has studied neutrinos coming through the earth and provided results on atmospheric muon flux. [Wikipedia link]
  • 2007-2017 Borexino : This neutrino detector is located at the underground Gran Sasso laboratory. It is a large liquid scintillator detector whose first goal is the detection and study of low energy solar neutrinos. Its configuration allows to detect beryllium-7, boron-8, pp, pep and CNO solar neutrinos as well as anti-neutrinos from the Earth or nuclear power plants. Borexino may also be able to detect neutrinos from supernovae  and is part of the SNEWS alert system. [Wikipedia link]
  • 2011-2018 IceCube : This high energy neutrino observatory is located at the Amundsen–Scott South Pole Station in Antarctica. Its first part, called AMANDA, was in  operation until May 2009. IceCube detector was completed in December 2010 and took data until it announced in November 2013 the detection of 28 neutrinos whose origin may be outside of the solar system. IceCube is dedicated to high energy neutrinos from astrophysicall origin. It is manly composed of spherical sensors, with photomultipliers, distributed over a cubic kilometer, 1500 m, under the Antarctic ice and detecting the Cerenkov light emitted by high energy particles produced by neutrino interactions. In 2018, IceCube was still in operation and announced to have observed high energy neutrinos in coincidence with a gamma ray detection by Fermi satellite. [Wikipedia link]

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Other experiments that contributed to neutrino knowledge

  • 1957 Neutrino helicity (Goldhaber et al.): This experiment was made at Brookhaven. It used the electron capture by the nucleus of Europium 152 which produces a νe and a nucleus of Samarium 152, which emits a gamma ray whose helicity is the same as the neutrino one if they are emitted back to back. A NaI photomultiplier placed below a lead shield allowed to detect the gamma ray and to measure its polarization. The result showed without ambiguity that neutrinos have always a negative helicity. [Wikipedia link]
  • 1956 Cobalt60 experiment: This experiment was proposed by T.D. Lee and C.N. Yang and was done in 1956 by C.S. Wu in collaboration with the Low Temperature Group of the US National Bureau of Standards. Its purpose was to establish if weak interaction conserve or not the parity symetry.
    The important result of this experiment was that parity was violated by the weak interaction. This led to consider neutrinos, that interact only by weak interaction, with an other light. For this result T.D. Lee and C.N. Yang received the 1957 Nobel Prize in physics while C.S. Wu was awarded the first Wolf Prize in 1978. [Wikipedia link]
  • 1989-2000 LEP @ CERN : the Large Electron–Positron Collider (LEP) was a large circular particle accelerator built at CERN. Colliding electrons with positrons at energies up to 209 GeV, it provided, from 1989 to 2000, many new results and precision measurements about particle physics. One of them was the determination of the number of neutrino families (2.92 +- 0.05) from the measurement of the width of the Z boson by the ALEPH, OPAL, DELPHI and L3 experiments. [Wikipedia link]
  • 2003-2017 Planck : the Planck experiment is a satellite, an ESA’s mission to study the Cosmic Background Radiation Field over the whole sky, especially its temprature and polarization anisotropies. Planck was proposed around 1995 and the satellite was launched in May 2009. After COBE and WMAP, Planck provided in 2013 the most precise results about the CMB. It was a major source of information for cosmological studies. Together with BAO (Baryon Acoustic Oscillation) data, it provided in 2018, the most stringent cosmological constraint on the neutrino masses (m1+m2+m3 < 0.12 eV) and the number of neutrino families (2.99+-0.17).  [Wikipedia link]
  • 1987 Moe experiment : This experiment was done by Michael Moe and his collaborators and provided the direct proof of the existence of the double beta decay with neutrinos. It used a time projection chamber to identify the two electrons coming from the decay of 82Se. Since then, the double beta decay with neutrinos has been observed in about 12 nuclei, while we still wait eagerly for any evidence of double-beta decay without neutrinos, which would give the proof that neutrinos are Majorana particles. [Wikipedia link]
  • 2003-2011 NEMO3 : This neutrinoless double beta decay experimentwas the last version of the NEMO (Neutrnio Ettore Majorana Observatory) detector. It is located Modane Underground Laboratory.
    The detector is a cylinder made of 20 sectors that contain different isotopes in thin foils. Main ones are Molybdenium-100 and Selenium-82 which provide double beta decays, whose electrons or positrons are identified by a tracking detector in a magnetic field and an electromagnetic calorimeter. In addition Tellurium and Copper foils are used to measure the background. The next step of this collaboration is the SuperNEMO experiment. [Wikipedia link]
  • 2013 GERDA : This neutrinoless double beta decay experiment is located at the underground Gran Sasso laboratory. It use Ge76 crystals located inside a liquid argon tank. It was proposed in 2004 and started operation in 2013. One of the main results is a lower limit of 1026 years on the half-life of Ge76 neutrinoless double beta decay which is interpreted as a upper limit on neutrino mass of 0.3 eV. [Wikipedia link]
  • 2017 CUORE : This detector is looking for neutrinoless double beta decay at the underground Gran Sasso laboratory.  A preliminary version called Cuoricino took data from 2003 to 2008 and was the largest bolometer used with 62 TeO2 crystals. No neutrinoless double beta decay has been detected yet either with Cuoricino or Cuore. [Wikipedia link]
  • 1994-2004 Troitsk-numass: This experiment looked for neutrinos from 3H beta decay. It measured the end-point region of the beta-spectrum of tritium with an integral electrostatic spectrometer with adiabatic magnetic collimation and a gaseous tritium source. Last results came for a re-analysis of the data in 2011 and gave a limit on anti electron-neutrino mass: mνe< 2.05 eV at 95% CL. [Wikipedia link]
  • 2018-2023 KATRIN: This experiment looks for the spectrum of the electrons emitted from the beta decay of tritium. Thanks to a 200 tons spectrometer, it expect to get a precision on the neutrino mass below 1 eV. It is one of the few experiments trying to determine the absolute mass of the νe . [Wikipedia link]