Draft:Project 8 (physics experiment)

{{AFC comment|1=Wikipedia is a trailing encyclopedia, not a leading newspaper. As such there are only pages on established results. This project may turn out to be important, but at the moment there does not seem to be any results so it is WP:TOOSOON. At most add a couple of sentences to the neutron page, but even that might be premature.

I suggest leaving it, and when there are positive results revising then resubmitting.

N.B., you can also check WT:Physics#Project 8 (physics experiment) -- too soon? Ldm1954 (talk) 18:46, 15 January 2025 (UTC)}}

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{{Draft article}}

{{Short description|Collaborative experiment on neutrinos}}

Project 8 is an international collaboration of physicists intending to measure the absolute mass of the neutrinoMore specifically, the electron-weighted neutrino mass; see the page on Neutrinos - Flavor, mass, and their mixing for details. with a sensitivity of approximately 40 meV. {{Cite web |last=Kwon |first=Diana |date=2015-05-20 |title=Small teams, big dreams {{!}} symmetry magazine |url=https://www.symmetrymagazine.org/article/may-2015/small-teams-big-dreams |access-date=2024-11-18 |website=www.symmetrymagazine.org |language=en}}{{Cite web |title=Циклотронное излучение открывает новые возможности для измерения массы нейтрино • Новости науки |url=https://elementy.ru/novosti_nauki/432468 |access-date=2024-11-18 |website=«Элементы» |language=ru}}{{Cite web |last=Overgaard |first=Elise |date=2023-01-24 |title=Ways to weigh a neutrino {{!}} symmetry magazine |url=https://www.symmetrymagazine.org/article/ways-to-weigh-a-neutrino |access-date=2024-11-18 |website=www.symmetrymagazine.org |language=en}}{{Cite journal |last=Huber |first=Patrick |date=2015-04-20 |title=Cyclotron Radiation from One Electron |url=https://physics.aps.org/articles/v8/36 |journal=Physics |language=en |volume=8 |issue=16 |pages=36 |doi=10.1103/PhysRevLett.114.162501|pmid=25955048 |arxiv=1408.5362 |bibcode=2015PhRvL.114p2501A }}

The experiment measures the beta decay of tritium. The energy spectrum of beta-decay electrons depends on the mass of the electron antineutrino. A non-zero neutrino mass will distort the shape of the highest-energy part of the energy spectrum.{{Cite web |title=Neutrino Mass Experiment - About |url=https://www.project8.org/about |access-date=2024-11-18 |website=www.project8.org |language=en-US}} Project 8 relies on cyclotron radiation from single electrons produced in beta decay in order to measure their energy, a method dubbed CRES (Cyclotron Radiation Emission Spectroscopy). The cyclotron radiation is captured using a microwave waveguide (as in the first demonstration) or a resonant cavity (as considered for future phases{{cite arXiv

| collaboration = Project 8 Collaboration

| date = 2022-03-14

| title = The Project 8 Neutrino Mass Experiment

| eprint = 2203.07349

| class = physics.ins-det

| author1 = Project 8 Collaboration

| last2 = Ashtari Esfahani

| first2 = A.

| last3 = Böser

| first3 = S.

| last4 = Buzinsky

| first4 = N.

| last5 = Carmona-Benitez

| first5 = M. C.

| last6 = Claessens

| first6 = C.

| last7 = de Viveiros

| first7 = L.

| last8 = Doe

| first8 = P. J.

| last9 = Enomoto

| first9 = S.

| last10 = Fertl

| first10 = M.

| last11 = Formaggio

| first11 = J. A.

| last12 = Gaison

| first12 = J. K.

| last13 = Grando

| first13 = M.

| last14 = Heeger

| first14 = K. M.

| last15 = Huyan

| first15 = X.

| last16 = Jones

| first16 = A. M.

| last17 = Kazkaz

| first17 = K.

| last18 = Li

| first18 = M.

| last19 = Lindman

| first19 = A.

| last20 = Matthé

| first20 = C.

| last21 = Mohiuddin

| first21 = R.

| last22 = Monreal

| first22 = B.

| last23 = Mueller

| first23 = R.

| last24 = Nikkel

| first24 = J. A.

| last25 = Novitski

| first25 = E.

| last26 = Oblath

| first26 = N. S.

| last27 = Peña

| first27 = J. I.

| last28 = Pettus

| first28 = W.

| last29 = Reimann

| first29 = R.

| last30 = Robertson

| first30 = R. G. H.

| display-authors = 1

}}). This method was successfully demonstrated in Phase I of Project 8, marking the first measurement of cyclotron radiation from a single electron.{{Cite journal |last1=Asner |first1=D. M. |last2=Bradley |first2=R. F. |last3=de Viveiros |first3=L. |last4=Doe |first4=P. J. |last5=Fernandes |first5=J. L. |last6=Fertl |first6=M. |last7=Finn |first7=E. C. |last8=Formaggio |first8=J. A. |last9=Furse |first9=D. |last10=Jones |first10=A. M. |last11=Kofron |first11=J. N. |last12=LaRoque |first12=B. H. |last13=Leber |first13=M. |last14=McBride |first14=E. L. |last15=Miller |first15=M. L. |date=2015-04-20 |title=Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation |url=https://link.aps.org/doi/10.1103/PhysRevLett.114.162501 |journal=Physical Review Letters |language=en |volume=114 |issue=16 |page=162501 |doi=10.1103/PhysRevLett.114.162501 |pmid=25955048 |arxiv=1408.5362 |bibcode=2015PhRvL.114p2501A |issn=0031-9007}}

The beta decay source for the 40 meV experiment is planned to be atomic tritium. This provides higher precision than molecular tritium since an isolated atom has no rotational or vibrational states that can take up some of the decay's energy.{{cite journal |last1=Bodine |first1=L. I. |last2=Parno |first2=D. S. |last3=Robertson |first3=R. G. H. |title=Assessment of molecular effects on neutrino mass measurements from tritium β decay |journal=Physical Review C |date=27 March 2015 |volume=91 |issue=3 |page=035505 |doi=10.1103/PhysRevC.91.035505 |arxiv=1502.03497 |bibcode=2015PhRvC..91c5505B }}

Tritium beta decay has been used by a number of previous experiments, the current generation of which is KATRIN. its design uses a large spectrometer which would need to be enlarged to implausible proportions to materially improve its sensitivity. CRES is therefore a more promising method for a tritium-based next-generation direct neutrino-mass experiment.{{cite journal |last1=Formaggio |first1=Joseph A. |last2=de Gouvêa |first2=André Luiz C. |last3=Robertson |first3=R. G. Hamish |title=Direct measurements of neutrino mass |journal=Physics Reports |date=3 June 2021 |volume=914 |pages=1–54 |doi=10.1016/j.physrep.2021.02.002 |arxiv=2102.00594 |bibcode=2021PhR...914....1F }} Project 8 was mentioned in The 2023 Long Range Plan for Nuclear Science from the Nuclear Science Advisory Committee (NSAC) of the United States Department of Energy, which described the status of the field as follows:{{cite report |title=A New Era of Discovery: The 2023 Long Range Plan for Nuclear Science |date=1 October 2023 |doi=10.2172/2280968 |last1=None |first1=None |osti=2280968 }}

Any experiment that follows KATRIN will need two new technologies: (1) a scalable electron spectroscopy technique

to measure the tritium decay spectrum and (2) a tritium source consisting of atoms rather than the more

natural molecular form of this hydrogen isotope.