Found deep underground at the Baksan Neutrino Observatory in the Caucasus mountains in Russia, the finished two-zone gallium target, at left, consists of a external and inner tank of gallium, which is irradiated by an electron neutrino source. Credit: A.A. Shikhin
More than a mile underground in the Baksan Neutrino Observatory in Russias Caucasus Mountains, BEST used 26 irradiated disks of chromium 51, a synthetic radioisotope of chromium and the 3.4 megacurie source of electron neutrinos, to irradiate an inner and outer tank of gallium, a soft, silvery metal likewise used in previous experiments, though formerly in a one-tank set-up. The response in between the electron neutrinos from the chromium 51 and the gallium produces the isotope germanium 71.
The determined rate of germanium 71 production was 20-24% lower than expected based upon theoretical modeling. That disparity remains in line with the anomaly seen in previous experiments.
BEST constructs on a solar neutrino experiment, the Soviet-American Gallium Experiment (SAGE), in which Los Alamos National Laboratory was a significant factor, beginning in the late 1980s. That experiment likewise utilized gallium and high-intensity neutrino sources. The results of that experiment and others indicated a deficit of electron neutrinos– a discrepancy between the predicted and the actual results that happened called the “gallium anomaly.” An interpretation of the deficit might be proof for oscillations in between electron neutrino and sterilized neutrino states.
A set of 26 irradiated disks of chromium 51 are the source of electron neutrinos that react with gallium and produce germanium 71 at rates that can be measured versus anticipated rates. Credit: A.A. Shikhin
The very same abnormality recurred in the BEST experiment. The possible explanations once again include oscillation into a sterilized neutrino.
Other explanations for the anomaly consist of the possibility of a misconception in the theoretical inputs to the experiment– that the physics itself requires reworking. Elliott mentions that the cross-section of the electron neutrino has actually never been measured at these energies. A theoretical input to measuring the cross section, which is hard to validate, is the electron density at the atomic nucleus.
The experiments approach was completely evaluated to make sure no mistakes were made in elements of the research, such as radiation source placement or counting system operations. Future iterations of the experiment, if performed, may include a various radiation source with greater energy, longer half-life, and level of sensitivity to shorter oscillation wavelengths.
Recommendations:
” Results from the Baksan Experiment on Sterile Transitions (BEST)” by V. V. Barinov et al., 9 June 2022, Physical Review Letters.DOI: 10.1103/ PhysRevLett.128.232501.
” Search for electron-neutrino transitions to sterilized states in the very best experiment” by V. V. Barinov et al., 9 June 2022, Physical Review C.DOI: 10.1103/ PhysRevC.105.065502.
Financing: Department of Energy, Office of Science, Office of Nuclear Physics.
New arise from the Baksan Experiment on Sterile Transitions (BEST) experiment validate anomaly recommending new physics possibility.
Sterile neutrino, physics principles among analyses of anomalous outcomes.
New clinical outcomes verify an anomaly seen in previous experiments, which might point to an as-yet-unconfirmed new primary particle, the sterilized neutrino, or indicate the need for a brand-new interpretation of an element of basic model physics, such as the neutrino cross section, first measured 60 years ago. Los Alamos National Laboratory is the lead American institution teaming up on the Baksan Experiment on Sterile Transitions (BEST) experiment, outcomes of which were recently published in the journals Physical Review Letters and Physical Review C.
” The results are very extremelyInteresting” said Steve Elliott, lead analyst of one of the teams groups the data and a member of Los Alamos Physics division. “This absolutely declares the abnormality weve seen in previous experiments.
New scientific outcomes validate an anomaly seen in previous experiments, which might point to an as-yet-unconfirmed brand-new primary particle, the sterile neutrino, or indicate the requirement for a brand-new analysis of an element of standard design physics, such as the neutrino cross area, very first determined 60 years ago. Los Alamos National Laboratory is the lead American institution teaming up on the Baksan Experiment on Sterile Transitions (BEST) experiment, outcomes of which were recently published in the journals Physical Review Letters and Physical Review C.
” The results are very reallyInteresting” said Steve Elliott, lead analyst of one of the teams groups assessing data information a member of Los Alamos Physics divisionDepartment BEST builds on a solar neutrino experiment, the Soviet-American Gallium Experiment (SAGE), in which Los Alamos National Laboratory was a significant factor, beginning in the late 1980s. That experiment likewise utilized gallium and high-intensity neutrino sources. Other descriptions for the abnormality consist of the possibility of a misunderstanding in the theoretical inputs to the experiment– that the physics itself requires remodeling.