Reanalysis of the $β- \bar{ν_e}$ Angular Correlation Measurement from the aSPECT Experiment with New Constraints on Fierz Interference
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2023
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866913266975899648 |
|---|---|
| author | Beck, M. Heil, W. Schmidt, C. Baeßler, S. Glück, F. Konrad, G. Schmidt, U. |
| author_facet | Beck, M. Heil, W. Schmidt, C. Baeßler, S. Glück, F. Konrad, G. Schmidt, U. |
| contents | On the basis of revisions of some of the systematic errors, we reanalyzed the electron-antineutrino angular correlation ($a$ coefficient) in free neutron decay inferred from the recoil energy spectrum of the protons which are detected in 4$π$ by the aSPECT spectrometer. With $a = -0.10402(82)$ the new value differs only marginally from the one published in 2020. The experiment also has sensitivity to $b$, the Fierz interference term. From a correlated $(b,a)$ fit to the proton recoil spectrum, we derive a limit of $b = -0.0098(193)$ which translates into a somewhat improved 90 \% CL region of $-0.041 \leq b \leq 0.022$ on this hypothetical term. Tighter constraints on $b$ can be set from a combined$^{(c)}$ analysis of the PERKEO~III ($β$ asymmetry) and aSPECT measurement which suggests a finite value of $b$ with $b^{(c)}$ = -0.0181 $\pm$ 0.0065 deviating by 2.82$σ$ from the standard model. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2308_16170 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Reanalysis of the $β- \bar{ν_e}$ Angular Correlation Measurement from the aSPECT Experiment with New Constraints on Fierz Interference Beck, M. Heil, W. Schmidt, C. Baeßler, S. Glück, F. Konrad, G. Schmidt, U. Nuclear Experiment On the basis of revisions of some of the systematic errors, we reanalyzed the electron-antineutrino angular correlation ($a$ coefficient) in free neutron decay inferred from the recoil energy spectrum of the protons which are detected in 4$π$ by the aSPECT spectrometer. With $a = -0.10402(82)$ the new value differs only marginally from the one published in 2020. The experiment also has sensitivity to $b$, the Fierz interference term. From a correlated $(b,a)$ fit to the proton recoil spectrum, we derive a limit of $b = -0.0098(193)$ which translates into a somewhat improved 90 \% CL region of $-0.041 \leq b \leq 0.022$ on this hypothetical term. Tighter constraints on $b$ can be set from a combined$^{(c)}$ analysis of the PERKEO~III ($β$ asymmetry) and aSPECT measurement which suggests a finite value of $b$ with $b^{(c)}$ = -0.0181 $\pm$ 0.0065 deviating by 2.82$σ$ from the standard model. |
| title | Reanalysis of the $β- \bar{ν_e}$ Angular Correlation Measurement from the aSPECT Experiment with New Constraints on Fierz Interference |
| topic | Nuclear Experiment |
| url | https://arxiv.org/abs/2308.16170 |