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Mulan: a part-per-million measurement of the muon lifetime and determination of the Fermi constant
by R. Carey, T. Gorringe, D.W. Hertzog
This is not the latest submitted version.
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Submission summary
| Authors (as registered SciPost users): | Tim Gorringe |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202102_00014v1 (pdf) |
| Date submitted: | 2021-02-09 14:33 |
| Submitted by: | Gorringe, Tim |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | Review of Particle Physics at PSI (PSI2020) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Experimental |
Abstract
The part-per-million measurement of the positive muon lifetime and determination of the Fermi constant by the MuLan experiment at the Paul Scherrer Institute is reviewed. The experiment used an innovative, time-structured, surface muon beam and a near-4π, finely-segmented, plastic scintillator positron detector. Two in-vacuum muon stopping targets were used: a ferromagnetic foil with a large internal magnetic field, and a quartz crystal in a moderate external magnetic field. The experiment acquired a dataset of 1.6e12 positive muon decays and obtained a muon lifetime τ_µ = 2 196 980.3(2.2) ps (1.0 ppm) and Fermi constant G_F = 1.166 378 7(6) × 10−5 GeV^−2 (0.5 ppm). The thirty fold improvement in τ_µ has proven valuable for precision measurements in nuclear muon capture and the commensurate improvement in G_F has proven valuable for precision tests of the standard model.
Current status:
Reports on this Submission
Report #2 by Adrian Signer (Referee 1) on 2021-2-26 (Invited Report)
- Cite as: Adrian Signer, Report on arXiv:scipost_202102_00014v1, delivered 2021-02-26, doi: 10.21468/SciPost.Report.2618
Report
We (the editors Cy Hoffman, Klaus Kirch, Adrian Signer) had the
opportunity to review an earlier draft of the article and were in
communication with the authors before the submission. All our comments
and suggestions have been taken into account. Hence, we think the
paper can now be published in the current form.
Report #1 by Philipp Schmidt-Wellenburg (Referee 2) on 2021-2-23 (Invited Report)
- Cite as: Philipp Schmidt-Wellenburg, Report on arXiv:scipost_202102_00014v1, delivered 2021-02-23, doi: 10.21468/SciPost.Report.2600
Report
The PSI review article
"Mulan: a part-per-million measurement of the muon lifetime and
determination of the Fermi constant"
describes brief and comprehensive the impressive work performed by the muLan collaboration
resulting in the most precise measured lifetime of the positive muon.
This work is a cornerstone of particle physics and a beacon of PSI's particle physics laboratory.
The paper is ready for publication after the authors address the following minor remarks.
Requested changes
Line 68: the acronym MSPS is not defined
Line 79: unsure if "collimator" is the correct term, I would think the term "beam dump" would better suit.
Line 202: DOI link is not to the main article but to a publisher's note.
Line 209: Add link to paper: http://ivanik3.narod.ru/TimeLifeMezon/e_040_05_0811Balandin.pdf
- All arxiv links in the references do not work. This is probably a bibtex issue.
Author: Tim Gorringe on 2021-03-04 [id 1285]
(in reply to Report 2 by Adrian Signer on 2021-02-26)1) the authors are fine with replacing MSPS with either MHz or mega-samples-per-second as preferred by referee / editor
2) the collimator was a adjustable, horizontal slit. To the authors the word collimator is more accurate than beam dump.
3) the correct doi link is 10.1103/PhysRevLett.106.041803
thank you!