SciPost Submission Page

MuCap: Muon Capture on the Proton

by Malte Hildebrandt and Claude Petitjean

This is not the current version.

Submission summary

As Contributors: Malte Hildebrandt
Preprint link: scipost_202101_00009v1
Date submitted: 2021-01-13 17:17
Submitted by: Hildebrandt, Malte
Submitted to: SciPost Physics Proceedings
Proceedings issue: PSI Particle Physics
Academic field: Physics
  • Nuclear Physics - Experiment
Approach: Experimental


The singlet muon capture rate $\Lambda_S$ on the proton $\mu^-\ p \to \nu_\mu n$ is determined in a high precision lifetime measurement. The main apparatus consists of a new hydrogen time projection chamber as muon detector, developed by PSI, surrounded by cylindrical wire chambers and a plastic scintillator hodoscope as electron detectors. $\Lambda_S$ is evaluated as the difference between the inverse $\mu\,p$ lifetime and that of the free $\mu^+$. The result $\Lambda_S^\text{MuCap} = (715.6 \pm 5.4^\text{stat} \pm 5.1^\text{sys})\,\text{s}^{-1}$ is in excellent agreement with the prediction of chiral perturbation theory $\Lambda_S^{\chi\text{PT}} = (715.4 \pm 6.9)\,\text{s}^{-1}$. From $\Lambda_S^\text{MuCap}$ a recent analysis derives for the induced pseudoscalar coupling $g^\text{MuCap}_p = 8.23 \pm 0.83$ whereas $\bar{g}^{\chi\text{PT}}_p = 8.25 \pm 0.25$.}

Current status:
Has been resubmitted

Submission & Refereeing History

Resubmission scipost_202101_00009v3 on 3 February 2021
Resubmission scipost_202101_00009v2 on 1 February 2021

Reports on this Submission

Anonymous Report 1 on 2021-1-30 (Invited Report)


This is a beautiful experiment and I recommend publication! I have only a few very minor and only formal suggestions for changes, see below

Requested changes

1) If one follows the the AIP Style manual, one should avoid to start a new sentence with a symbol or a number. So, one might change on line 11 ,,Lambda_s is evaluated... by e.g. ,,The parameter Lambda_s is evaluated ...

2) Line 20 g_p(??): One should correct this.

3) In the footnote on page 2: (??) , please correct.

4) The references [3,4] are mentioned on page 4 after reference [20] only. So, in the list of references, one should make the according changes.

  • validity: high
  • significance: high
  • originality: high
  • clarity: high
  • formatting: good
  • grammar: good

Author:  Malte Hildebrandt  on 2021-01-31

(in reply to Report 1 on 2021-01-30)
reply to objection

Thank you very much for your careful reading of the manuscript and your feedback.

Concerning your remark 1)
Thank you very much for pointing this out. We will keep this in mind and will correct according to the main editor's recommendations.

Concerning your remarks 2) and 3)
This manuscript is not a "stand-alone" paper, but part of a special volume in SciPost on particle physics at the Paul Scherrer Institut. The two "(??)" refer to the theory chapter of this special volume which is not yet submitted. In the tex-file the references to the theory chapter are already included and consequently appear currently only as "(??)".

Concerning your remark 4)
The references [3, 4] are already cited on page 1 in line 23. We think, the sequence of the references is correct - actually it is done automatically by LaTex.

Thanks and best regards, Malte Hildebrandt

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