[Neutron] Postdoctoral position on neutron lifetime experiment

Fertl, Prof. Dr. Martin mfertl at uni-mainz.de
Tue Oct 11 17:14:20 CEST 2022


To strengthen its neutron physics research program, the Johannes Gutenberg University Mainz offers
one postdoctoral position (100 % EG13) to work on the tSPECT experiment (https://ucn.uni-mainz.de/tauspect/) to measure the lifetime of the free neutron.
The lifetime of the free neutron is a key observable in low-energy tests of the Standard Model of Particle Physics (SM) with important implications throughout the evolution of the Universe. The neutron lifetime determines the ratio of 4He/H after the primordial nucleosynthesis. And within the SM only three (low-energy) parameters are required for a highprecision description of the free neutron decay: The CKM matrix element Vud, the ratio of axial-vector and vector coupling strength gA/gV, and the free neutron lifetime. Therefore, a precise determination of the neutron lifetime contributes to a very stringent test of the SM prediction and any deviation thereof could be a tantalizing hint to physics beyond the SM.

The tSPECT experiment is installed at the source of ultra-cold neutrons (UCN) at JGU’s own TRIGA reactor. We follow the approach to measure the fraction of neutrons surviving for a variable storage time in a so-called neutron bottle. This bottle is formed by a region of a magnetic field minimum surrounded by strong positive magnetic field gradients. Through the neutron’s electromagnetic interaction potential, neutrons in the low-field-seeking spin state get trapped without contact to material walls where the spurious neutron absorption could occur. To “close” the UCN-bottle after the filling process tSPECT uses a unique approach. By applying a radio-frequency pulse, initially high-field seeking UCN are converted into the storable, low-field seeking state. This way also the closing of the bottle happens contact-less and without the need to physically move magnet arrangements. The tSPECT experiment is currently in its commissioning phase. The postdoctoral scholar will participate in the data accumulation during beam times and drive the efforts for detailed Monte-Carlo simulations of the experiment that will be required to understand effects that could systematically bias the extracted neutron lifetime result. Working experience with various UCN-specific MC packages is desireable.

Please send your application, including

· a cover letter
· a research statement about previous and current research experience (1-page max., 12 pt)
· a CV
· the name and email address of two providers of letters of reference (no letter initially required)
· copies of relevant certificates and grades, and transcripts of records

to Prof. Dr. Martin Fertl (jobs-agfertl at uni-mainz.de<mailto:jobs-agfertl at uni-mainz.de>) (electronic application materials only). Review of the received application will start after November 30th, 2022, but the position will remain open until filled. Please do not hesitate to contact Prof. Dr. Martin Fertl in case of any questions.

Prof. Dr. Martin Fertl (pronouns: he/him/his)
Johannes Gutenberg University Mainz
Institute of Physics

Staudingerweg 7
55128 Mainz, Germany

Office: 02-627
Phone: +49 6131 39-37687
Email: mfertl at uni-mainz.de<mailto:mfertl at uni-mainz.de>

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