Data blinding for the nEDM experiment at PSI

N. J. Ayres; G. Ban; G. Bison; K. Bodek; V. Bondar; E. Chanel; P. J. Chiu; C. B. Crawford; M. Daum; S. Emmenegger; L. Ferraris-Bouchez; P. Flaux; Z. Grujić; P. G. Harris; N. Hild; J. Hommet; M. Kasprzak; Y. Kermaïdic; K. Kirch; S. Komposch; A. Kozela; J. Krempel; B. Lauss; T. Lefort; Y. Lemiere; A. Leredde; P. Mohanmurthy; A. Mtchedlishvili; O. Naviliat-Cuncic; D. Pais; F. M. Piegsa; G. Pignol; M. Rawlik; D. Rebreyend; I. Rienäcker; D. Ries; S. Roccia; D. Rozpedzik; P. Schmidt-Wellenburg; A. Schnabel; R. Virot; A. Weis; E. Wursten; J. Zejma; G. Zsigmond

doi:10.1140/epja/s10050-021-00456-1

Data blinding for the nEDM experiment at PSI

N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, E. Chanel, P. J. Chiu, C. B. Crawford, M. Daum, S. Emmenegger, L. Ferraris-Bouchez, P. Flaux, Z. Grujić, P. G. Harris, N. Hild, J. Hommet, M. Kasprzak, Y. Kermaïdic, K. Kirch, S. KomposchA. Kozela, J. Krempel, B. Lauss, T. Lefort, Y. Lemiere, A. Leredde, P. Mohanmurthy, A. Mtchedlishvili, O. Naviliat-Cuncic, D. Pais, F. M. Piegsa, G. Pignol, M. Rawlik, D. Rebreyend, I. Rienäcker, D. Ries, S. Roccia, D. Rozpedzik, P. Schmidt-Wellenburg, A. Schnabel, R. Virot, A. Weis, E. Wursten, J. Zejma, G. Zsigmond

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Abstract

Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.

Original language	English
Article number	152
Journal	European Physical Journal A
Volume	57
Issue number	4
DOIs	https://doi.org/10.1140/epja/s10050-021-00456-1
State	Published - Apr 2021

Bibliographical note

Funding Information:
We gratefully acknowledge financial support from the Swiss National Science Foundation through project grants 149211, 162574 and 172639 for the ETHZ group, grant 181996 for the Bern group and grants 117696, 144473, 137664, 163413, 169596, and 171626 for the PSI group. This work was funded in part by the United Kingdom Science and Technology Facilities Council (STFC) through grants ST/N000307/1 and ST/M503836/1, as well as by the School of Mathematical and Physical Sciences at the University of Sussex. One of the authors (P. M.) would like to acknowledge support from the Swiss State Secretariat for Education, Research and Innovation (SERI) - Federal Commission for Scholarships (FCS) award #2015.0594. We likewise gratefully acknowledge financial support from the Polish National Science Center, through grants UMO-2015/18/M/ST2/00056, UMO-2016/23/D/ST2/00715 and UMO-2018/30/M/ST2/00319. We are most grateful for the excellent support provided by the PSI technical groups and by various services of the collaborating universities and research laboratories.

Publisher Copyright:
© 2021, The Author(s).

ASJC Scopus subject areas

Nuclear and High Energy Physics

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10.1140/epja/s10050-021-00456-1

Cite this

Ayres, N. J., Ban, G., Bison, G., Bodek, K., Bondar, V., Chanel, E., Chiu, P. J., Crawford, C. B., Daum, M., Emmenegger, S., Ferraris-Bouchez, L., Flaux, P., Grujić, Z., Harris, P. G., Hild, N., Hommet, J., Kasprzak, M., Kermaïdic, Y., Kirch, K., ... Zsigmond, G. (2021). Data blinding for the nEDM experiment at PSI. European Physical Journal A, 57(4), [152]. https://doi.org/10.1140/epja/s10050-021-00456-1

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title = "Data blinding for the nEDM experiment at PSI",

abstract = "Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.",

author = "Ayres, {N. J.} and G. Ban and G. Bison and K. Bodek and V. Bondar and E. Chanel and Chiu, {P. J.} and Crawford, {C. B.} and M. Daum and S. Emmenegger and L. Ferraris-Bouchez and P. Flaux and Z. Gruji{\'c} and Harris, {P. G.} and N. Hild and J. Hommet and M. Kasprzak and Y. Kerma{\"i}dic and K. Kirch and S. Komposch and A. Kozela and J. Krempel and B. Lauss and T. Lefort and Y. Lemiere and A. Leredde and P. Mohanmurthy and A. Mtchedlishvili and O. Naviliat-Cuncic and D. Pais and Piegsa, {F. M.} and G. Pignol and M. Rawlik and D. Rebreyend and I. Rien{\"a}cker and D. Ries and S. Roccia and D. Rozpedzik and P. Schmidt-Wellenburg and A. Schnabel and R. Virot and A. Weis and E. Wursten and J. Zejma and G. Zsigmond",

note = "Funding Information: We gratefully acknowledge financial support from the Swiss National Science Foundation through project grants 149211, 162574 and 172639 for the ETHZ group, grant 181996 for the Bern group and grants 117696, 144473, 137664, 163413, 169596, and 171626 for the PSI group. This work was funded in part by the United Kingdom Science and Technology Facilities Council (STFC) through grants ST/N000307/1 and ST/M503836/1, as well as by the School of Mathematical and Physical Sciences at the University of Sussex. One of the authors (P. M.) would like to acknowledge support from the Swiss State Secretariat for Education, Research and Innovation (SERI) - Federal Commission for Scholarships (FCS) award #2015.0594. We likewise gratefully acknowledge financial support from the Polish National Science Center, through grants UMO-2015/18/M/ST2/00056, UMO-2016/23/D/ST2/00715 and UMO-2018/30/M/ST2/00319. We are most grateful for the excellent support provided by the PSI technical groups and by various services of the collaborating universities and research laboratories. Publisher Copyright: {\textcopyright} 2021, The Author(s).",

year = "2021",

month = apr,

doi = "10.1140/epja/s10050-021-00456-1",

language = "English",

volume = "57",

number = "4",

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Ayres, NJ, Ban, G, Bison, G, Bodek, K, Bondar, V, Chanel, E, Chiu, PJ, Crawford, CB, Daum, M, Emmenegger, S, Ferraris-Bouchez, L, Flaux, P, Grujić, Z, Harris, PG, Hild, N, Hommet, J, Kasprzak, M, Kermaïdic, Y, Kirch, K, Komposch, S, Kozela, A, Krempel, J, Lauss, B, Lefort, T, Lemiere, Y, Leredde, A, Mohanmurthy, P, Mtchedlishvili, A, Naviliat-Cuncic, O, Pais, D, Piegsa, FM, Pignol, G, Rawlik, M, Rebreyend, D, Rienäcker, I, Ries, D, Roccia, S, Rozpedzik, D, Schmidt-Wellenburg, P, Schnabel, A, Virot, R, Weis, A, Wursten, E, Zejma, J & Zsigmond, G 2021, 'Data blinding for the nEDM experiment at PSI', European Physical Journal A, vol. 57, no. 4, 152. https://doi.org/10.1140/epja/s10050-021-00456-1

TY - JOUR

T1 - Data blinding for the nEDM experiment at PSI

AU - Ayres, N. J.

AU - Ban, G.

AU - Bison, G.

AU - Bodek, K.

AU - Bondar, V.

AU - Chanel, E.

AU - Chiu, P. J.

AU - Crawford, C. B.

AU - Daum, M.

AU - Emmenegger, S.

AU - Ferraris-Bouchez, L.

AU - Flaux, P.

AU - Grujić, Z.

AU - Harris, P. G.

AU - Hild, N.

AU - Hommet, J.

AU - Kasprzak, M.

AU - Kermaïdic, Y.

AU - Kirch, K.

AU - Komposch, S.

AU - Kozela, A.

AU - Krempel, J.

AU - Lauss, B.

AU - Lefort, T.

AU - Lemiere, Y.

AU - Leredde, A.

AU - Mohanmurthy, P.

AU - Mtchedlishvili, A.

AU - Naviliat-Cuncic, O.

AU - Pais, D.

AU - Piegsa, F. M.

AU - Pignol, G.

AU - Rawlik, M.

AU - Rebreyend, D.

AU - Rienäcker, I.

AU - Ries, D.

AU - Roccia, S.

AU - Rozpedzik, D.

AU - Schmidt-Wellenburg, P.

AU - Schnabel, A.

AU - Virot, R.

AU - Weis, A.

AU - Wursten, E.

AU - Zejma, J.

AU - Zsigmond, G.

N1 - Funding Information: We gratefully acknowledge financial support from the Swiss National Science Foundation through project grants 149211, 162574 and 172639 for the ETHZ group, grant 181996 for the Bern group and grants 117696, 144473, 137664, 163413, 169596, and 171626 for the PSI group. This work was funded in part by the United Kingdom Science and Technology Facilities Council (STFC) through grants ST/N000307/1 and ST/M503836/1, as well as by the School of Mathematical and Physical Sciences at the University of Sussex. One of the authors (P. M.) would like to acknowledge support from the Swiss State Secretariat for Education, Research and Innovation (SERI) - Federal Commission for Scholarships (FCS) award #2015.0594. We likewise gratefully acknowledge financial support from the Polish National Science Center, through grants UMO-2015/18/M/ST2/00056, UMO-2016/23/D/ST2/00715 and UMO-2018/30/M/ST2/00319. We are most grateful for the excellent support provided by the PSI technical groups and by various services of the collaborating universities and research laboratories. Publisher Copyright: © 2021, The Author(s).

PY - 2021/4

Y1 - 2021/4

N2 - Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.

AB - Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.

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ER -

Data blinding for the nEDM experiment at PSI

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