LSND
Encyclopedia
The Liquid Scintillator Neutrino Detector (LSND) was a scintillation counter
at Los Alamos National Laboratory
that measured the number of neutrino
s being produced by an accelerator neutrino source. The LSND project was created to look for evidence of neutrino oscillation
, and its results conflict with the standard model expectation of only three neutrino flavors, when considered in the context of other solar and atmospheric neutrino oscillation experiments. Cosmological data bound the mass of the sterile neutrino to ms < 0.26eV (0.44eV) at 95% (99.9%) confidence limit, excluding at high significance the sterile neutrino hypothesis
as an explanation of the LSND anomaly. The controversial LSND result was tested by the MiniBooNE
experiment at Fermilab
, which refuted a simple 2-neutrino oscillation interpretation of the LSND result.
The detector consisted of a tank filled with 167 tons (50,000 gallons) of mineral oil
and 14 pounds (6.4 kg) of b-PDB (2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole) organic scintillator material. Cherenkov light
emitted by particle interactions was detected by an array of 1220 photomultiplier
tubes. The experiment collected data from 1993 to 1998.
Scintillation counter
A scintillation counter measures ionizing radiation. The sensor, called a scintillator, consists of a transparent crystal, usually phosphor, plastic , or organic liquid that fluoresces when struck by ionizing radiation. A sensitive photomultiplier tube measures the light from the crystal...
at Los Alamos National Laboratory
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...
that measured the number of neutrino
Neutrino
A neutrino is an electrically neutral, weakly interacting elementary subatomic particle with a half-integer spin, chirality and a disputed but small non-zero mass. It is able to pass through ordinary matter almost unaffected...
s being produced by an accelerator neutrino source. The LSND project was created to look for evidence of neutrino oscillation
Neutrino oscillation
Neutrino oscillation is a quantum mechanical phenomenon predicted by Bruno Pontecorvowhereby a neutrino created with a specific lepton flavor can later be measured to have a different flavor. The probability of measuring a particular flavor for a neutrino varies periodically as it propagates...
, and its results conflict with the standard model expectation of only three neutrino flavors, when considered in the context of other solar and atmospheric neutrino oscillation experiments. Cosmological data bound the mass of the sterile neutrino to ms < 0.26eV (0.44eV) at 95% (99.9%) confidence limit, excluding at high significance the sterile neutrino hypothesis
Sterile neutrino
Sterile neutrinosIn scientific literature, these particles are also variously referred to as right-handed neutrinos, inert neutrinos, heavy neutrinos, or neutral heavy leptons . are a hypothetical type of neutrino that do not interact via any of the fundamental interactions of the Standard Model...
as an explanation of the LSND anomaly. The controversial LSND result was tested by the MiniBooNE
MiniBooNE
MiniBooNE is an experiment at Fermilab designed to observe neutrino oscillations . A neutrino beam consisting primarily of muon neutrinos is directed at a detector filled with 800 tons of mineral oil and lined with 1,280 photomultiplier tubes...
experiment at Fermilab
Fermilab
Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...
, which refuted a simple 2-neutrino oscillation interpretation of the LSND result.
The detector consisted of a tank filled with 167 tons (50,000 gallons) of mineral oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
and 14 pounds (6.4 kg) of b-PDB (2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole) organic scintillator material. Cherenkov light
Cherenkov radiation
Cherenkov radiation is electromagnetic radiation emitted when a charged particle passes through a dielectric medium at a speed greater than the phase velocity of light in that medium...
emitted by particle interactions was detected by an array of 1220 photomultiplier
Photomultiplier
Photomultiplier tubes , members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum...
tubes. The experiment collected data from 1993 to 1998.