The Physics of Ultracold Neutrons and Fierz Interference in Beta Decay
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NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS and POLARIZED 3He
NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K. LAMOREAUXb aHahfl_Mejtfler Institut, Postfach 390128, Glienicker Strasse 100, 14109 Berlin, Germany b University of Washington, Department of Physics FM-15, Seattle, WA 98195, USA NORTH-HOLLAND PHYSICS REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1—62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb aHahnMeitner Institut, Postfach 390128, Glienicker Strasse 100, 14109 Berlin, Germany buniversily of Washington, Department of Physics FM-15, Seattle, WA 98195, USA Received May 1993; editor: J. Eichler Contents: 1. Introduction 4 5.3. Solution by use of the secular approximation 38 1.1. Historical background 4 5.4. Elimination of the pseudomagnetic field 2. Current experimental technique 8 suppression by feedback to w~ 39 2.1. Ultracold neutrons (UCN) 8 5.5. Effects of the z component of the pseudomagnetic 2.2. Neutron EDM measurements with stored UCN 10 field 42 2.3. Recent EDM experiments using UCN 13 5,6. Effects of offsets in the first-harmonic signal 44 3. Superfluid He neutron EDM with 3He 6. Noise analysis 45 comagnetometer 19 6.1. Model of the system for noise analysis 45 3.1. Introduction 19 6.2. Initial polarization and UCN density 45 3.2. Production of UCN in superfluid 4He 20 6.3. Analysis of harmonically modulated dressing 46 3.3. Polarization of UCN 21 6.4. Evolution of the UCN polarization and density 3.4. Polarization of 3He 22 under modulated dressing 46 3.5. -
Neutron Scattering Facilities in Europe Present Status and Future Perspectives
2 ESFRI Physical Sciences and Engineering Strategy Working Group Neutron Landscape Group Neutron scattering facilities in Europe Present status and future perspectives ESFRI scrIPTa Vol. 1 ESFRI Scripta Volume I Neutron scattering facilities in Europe Present status and future perspectives ESFRI Physical Sciences and Engineering Strategy Working Group Neutron Landscape Group i ESFRI Scripta Volume I Neutron scattering facilities in Europe - Present status and future perspectives Author: ESFRI Physical Sciences and Engineering Strategy Working Group - Neutron Landscape Group Scientific editors: Colin Carlile and Caterina Petrillo Foreword Technical editors: Marina Carpineti and Maddalena Donzelli ESFRI Scripta series will publish documents born out of special studies Cover image: Diffraction pattern from the sugar-binding protein Gal3c with mandated by ESFRI to high level expert groups, when of general interest. lactose bound collected using LADI-III at ILL. Picture credits should be given This first volume reproduces the concluding report of an ad-hoc group to D. Logan (Lund University) and M. Blakeley (ILL) mandated in 2014 by the Physical Science and Engineering Strategy Design: Promoscience srl Work Group (PSE SWG) of ESFRI, to develop a thorough analysis of the European Landscape of Research Infrastructures devoted to Neutron Developed on behalf of the ESFRI - Physical Sciences and Engineering Strategy Scattering, and its evolution in the next decades. ESFRI felt the urgency Working Group by the StR-ESFRI project and with the support of the ESFRI of such analysis, since many reactor-based neutron sources will be closed Secretariat down in the next years due to national decisions, while the European The StR-ESFRI project has received funding from the European Union’s Spallation Source (ESS) in Lund will be fully operative only in the mid Horizon 2020 research and innovation programme under grant agreement or late 2020s. -
Signa Ture Redacted' Signature Redacted
Ultracold Neutron Storage Simulation Using the MASSACUTS ILNSTITUTE Kassiopeia Software Package OF TECHNOLOGY by JUL 2 4 2019 Zachary Bogorad LIBRARIES Submitted to the Department of Physics ARCHIVES in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2019 Massachusetts Institute of Technology 2019. All rights reserved. Signa ture redacted' A uthor ............................ D 4 tment of Physics May 10, 2019 Signature redacted_ C ertified by ....................... ose . Formaggio rofessor of Physics Thesis Supervisor Signature redacted Accepted by ................ Nergis Mavalvala Associate Department Head, Department of Physics 2 Ultracold Neutron Storage Simulation Using the Kassiopeia Software Package by Zachary Bogorad Submitted to the Department of Physics on May 10, 2019, in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics Abstract The Kassiopeia software package was originally developed to simulate electromagnetic fields and charged particle trajectories for neutrino mass measurement experiments. Recent additions to Kassiopeia also allow it to simulate neutral particle trajectories in magnetic fields based on their magnetic moments. Two different methods were implemented: an exact method that can work for arbitrary fields and an adiabatic method that is limited to slowly-varying fields but is much faster for large precession frequencies. Additional interactions to simulate reflection of ultracold neutrons from material walls and to allow spin-flip pulses were also added. These tools were used to simulate neutron precession in the Paul Scherrer Institute's neutron electric dipole moment experiment and predict the values of the longitudinal and transverse relax- ation times as well as the trapping lifetime. -
Facilities and Methods Ultracold Neutrons—Physics and Production
facilities and methods Ultracold Neutrons—Physics and Production Introduction Free neutrons are the most funda- mental ones of the easily accessible, electrically neutral spin-1/2 systems. They take part in all the four known interactions: they strongly interact with nucleons and nuclear matter, they undergo weak β-decay, they have magnetic moments and gravitational mass. Although the neutron itself is a composite system, and thus, strictly speaking, not a fundamental particle, it is one of the finest probes for funda- mental physics. Neutrons can be and are used to study all interactions, to search for new interactions, to test fundamental quantum mechanics and symmetries of nature. Over the past five decades the field of slow neutron Figure 1. Dispersion relation of superfluid helium (c) and free neutron (a). precision physics developed and Neutrons with E » 1meV can excite a single phonon q » 0.7Å-1 with same energy could usually make major advance- and are thus down-scattered to the UCN energy range. The UCN production ments when new and more powerful rate (b) (circles) [16] shows the dominance of this single phonon process with neutron sources became available. respect to multiphonon processes. Very often experiments benefit from using slower neutrons and, thus, longer de Broglie wavelengths λ=2πh/(m · v), for example, thermal Besides numerous reviews, two new schemes for the production of neutrons at about 2,200 m/s average text books have been written on UCN UCN that have been studied in detail velocity have wavelengths of the typi- [2, 3]. For an update on the status of recently and are presently being real- cal atomic scale of about 1 Å. -
TRIUMF Ultracold Neutron Source
TRIUMF Ultracold Neutron Source J.W. Martin (Spokesperson)1, L. Buchmann2, J.D. Bowman3, L. Clarke4, C. Davis2, B.W. Filippone5, M. Gericke6, R. Golub4, K. Hatanaka7, M. Hayden8, T.M. Ito9, S. Jeong10, I. Kato2, S. Komamiya11, E. Korobkina4, E. Korkmaz12, L. Lee6, Y. Masuda9, K. Matsuta13, A. Micherdzinska1, W.D. Ramsay6, S.A. Page6, B. Plaster14, I. Tanihata7, W.T.H. van Oers6, Y. Watanabe10, S. Yamashita11, and T. Yoshioka11 1University of Winnipeg, Winnipeg, MB 2TRIUMF, Vancouver, BC 3Oak Ridge National Laboratory, Oak Ridge, TN, USA 4North Carolina State University, Raleigh, NC, USA 5California Institute of Technology, Pasadena, CA, USA 6University of Manitoba, Winnipeg, MB 7Research Center for Nuclear Physics, Osaka University, Osaka, Japan 8Simon Fraser University, Burnaby, BC 9Los Alamos National Laboratory, Los Alamos, NM, USA 10KEK, 1-1 Oho, Tsukuba, Ibaraki, Japan 11The University of Tokyo, Tokyo, Japan 12University of Northern British Columbia, Prince George, BC 13Osaka University, Toyonaka, Osaka, Japan 14University of Kentucky, Lexington, KY, USA March 17, 2008 1 Executive Summary We propose the construction of the world’s highest density source of ultracold neutrons (UCN) at TRIUMF. The truly high density that could be obtained at TRIUMF would allow a class of precision measurements to be conducted with significantly improved statistical and systematic uncertainties, and thus more significant results. This source would therefore make a major impact on studies of fundamental physics with UCN that would complement and enhance the ISAC program. A window of opportunity exists to capitalize on the successes of Y. Masuda’s group at KEK and at RCNP, thereby allowing the TRIUMF project to surpass other proposed sources elsewhere. -
Neutron Phase Spin Echo
PHYSICAL REVIEW C 93, 045501 (2016) Neutron phase spin echo Florian M. Piegsa,1,* Patrick Hautle,2 and Christian Schanzer3 1ETH Zurich,¨ Institute for Particle Physics, CH-8093 Zurich,¨ Switzerland 2Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland 3SwissNeutronics AG, CH-5313 Klingnau, Switzerland (Received 25 January 2016; revised manuscript received 11 February 2016; published 8 April 2016) A novel neutron spin resonance technique is presented based on the well-known neutron spin echo method. In a first proof-of-principle measurement using a monochromatic neutron beam, it is demonstrated that relative velocity changes of down to a precision of 4 × 10−7 can be resolved, corresponding to an energy resolution of better than 3 neV. Currently, the sensitivity is only limited by counting statistics and not by systematic effects. An improvement by another two orders of magnitude can be achieved with a dedicated setup, allowing energy resolutions in the 10 peV regime. The new technique is ideally suited for investigations in the field of precision fundamental neutron physics, but will also be beneficial in scattering applications. DOI: 10.1103/PhysRevC.93.045501 I. INTRODUCTION the neutron spins in and out of their plane of precession.1 Here, γ =−2π × 29.165 MHz/T is the gyromagnetic ratio of the The neutron spin echo (NSE) technique was first proposed n neutron [27]. Detailed theoretical descriptions of the spin flip by Mezei in 1972 [1]. It describes a very sensitive method process, NSE, and NRSE can be found in Refs. [28–30]. to determine small changes in the neutron velocity caused by inelastic scattering in a sample [2]. -
New Search for Mirror Neutron Regeneration
New Search for Mirror Neutron Regeneration L. J. Broussard1;∗, K. M. Bailey1, W. B. Bailey1, J. L. Barrow2, K. Berry1, A. Blose3, C. Crawford3, L. Debeer-Schmitt1, M. Frost1;2, A. Galindo-Uribarri1, F. X. Gallmeier1, C. E. Gilbert1;2, L. Heilbronn2, E. B. Iverson1, A. Johnston2, Y. Kamyshkov2, P. Lewiz2, I. Novikov4, S. I. Penttilä1, S. Vavra2, and A. R. Young5 1Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 2University of Tennessee, Knoxville, TN 37996 USA 3University of Kentucky, Lexington, KY 40506 USA 4Western Kentucky University, Bowling Green, KY 42101 USA 5North Carolina State University, Raleigh, NC 27695 USA Abstract. The possibility of relatively fast neutron oscillations into a mirror neutron state is not excluded experimentally when a mirror magnetic field is considered. Direct searches for the disappearance of neutrons into mirror neutrons in a controlled magnetic field have previously been performed using ultracold neutrons, with some anomalous results reported. We describe a technique using cold neutrons to perform a disappearance and regeneration search, which would allow us to unambiguously identify a possible oscillation signal. An experiment using the existing General Purpose-Small Angle Neutron Scattering instrument at the High Flux Isotope Reactor at Oak Ridge National Laboratory will have the sensitivity to fully explore the parameter space of prior ultracold neutron searches and confirm or refute previous claims of observation. This instrument can also conclusively test the validity of recently suggested oscillation-based explanations for the neutron lifetime anomaly. 1 Introduction that can resolve the ambiguity associated with the source of ultracold neutron losses [14, 15]. The astrophysical evidence for dark matter is strong. -
Chapter 15 Β Decay
Chapter 15 β Decay Note to students and other readers: This Chapter is intended to supplement Chapter 9 of Krane’s excellent book, ”Introductory Nuclear Physics”. Kindly read the relevant sections in Krane’s book first. This reading is supplementary to that, and the subsection ordering will mirror that of Krane’s, at least until further notice. β-particle’s are either electrons1 or positrons that are emitted through a certain class of nuclear decay associated with the “weak interaction”. The discoverer of electrons was Henri Becquerel, who noticed that photographic plates, covered in black paper, stored near ra- dioactive sources, became fogged. The black paper (meant to keep the plates unexposed) was thick enough to stop α-particles, and Becquerel concluded that fogging was caused by a new form of radiation, one more penetrating than α-particles. The name “β”, followed naturally as the next letter in the Greek alphabet after α, α-particles having already been discovered and named by Rutherford. Since that discovery, we have learned that β-particles are about 100 times more penetrating 1 than α-particles, and are spin- 2 fermions. Associated with the electrons is a conserved quantity, expressed as the quantum number known as the lepton number. The lepton number of the negatron is, by convention +1. The lepton number of the positron, also the anti- particle of the negatron, is -1. Thus, in a negatron-positron annihilation event, the next lepton number is zero. Only leptons can carry lepton number. (More on this soon.) Recall, from Chapter 13 (Chapter 6 in Krane), our discussion of the various decay modes that are associated with β decay: 1Technically, the word “electron” can represent either a negatron (a fancy word for e−) or a positron (e+). -
Abstract ANGULAR CORRELATIONS in FREE NEUTRON DECAY Jiirgen
365 ANGULAR CORRELATIONS IN FREE NEUTRON DECAY Jiirgen Last Institut Laue-Langevin 156 X 38042 Grenoble Cedex France Abstract The study of particle angular correlations in freeneutron decay provides important information about �-decay coupling constants, the structure of the hadronic weak current and possible extensions to the Standard Model. New experiments are expected to substantially reduce the uncertainty in the parity violating �-asymmetry A. The value of Yuct, which is currently derived from �-transition life times, might soon become available directly from neutron data. J7t=O+ An experiment which looks for time reversal violation in internal pair creation following polarized neutron captureon is briefly discussed. 366 NEIUTRON DECAY AND FUNDAMENTAL PHYSICS The term 'fundamental interaction' suggests that the physical system under study is elementary and prototypical for a whole class of similar processes. In this sense the weak decay of the neutron is clearly fundamental. Although the neutron possesses a complex internal structure, its quark contents is udd, it is the simplest baryonic system which undergoes semileptonic 13- decay. A neutron decays into a proton, an electron and an anti-neutrino. During this process one of the down-quarks is changed into an up-quark, emitting a W-boson which itsself decays into a pair of leptons. Since free quarks have not been observed in an experiment, neutron 13-decay is a very important source of information about the structure of the hadronic weak current and the weak coupling constants gA and gy. Their numerical values serve as input to nuclear astrop hysics problems, Big Bang cosmology, neutrino reactions and many other nuclear physics processes!. -
Letter of Interest Unitarity of CKM Matrix, |Vud|, Radiative Corrections
Snowmass2021 - Letter of Interest Unitarity of CKM Matrix, jVudj, Radiative Corrections and Semi-leptonic Form Factors Topical Groups: (EF04) EW Physics: EW Precision Physics and constraining new physics (EF05) QCD and strong interactions:Precision QCD (RF02) BSM: Weak decays of strange and light quarks (RF03) Fundamental Physics in Small Experiments (TF05) Lattice gauge theory (CompF2) Theoretical Calculations and Simulation Contact Information: Rajan Gupta (Los Alamos National Laboratory) [[email protected]]: Vincenzo Cirigliano (Los Alamos National Laboratory) [[email protected]] Collaboration: Precision Neutron Decay Matrix Elements (PNDME) and Nucleon Matrix Elements (NME) Authors: Tanmoy Bhattacharya (Los Alamos National Laboratory) [[email protected]] Steven Clayton (Los Alamos National Laboratory) [[email protected]] Vincenzo Cirigliano (Los Alamos National Laboratory) [[email protected]] Rajan Gupta (Los Alamos National Laboratory) [[email protected]] Takeyasu Ito (Los Alamos National Laboratory) [[email protected]] Yong-Chull Jang (Brookhaven National Laboratory) [[email protected]] Emanuele Mereghetti (Los Alamos National Laboratory) [[email protected]] Santanu Mondal (Los Alamos National Laboratory) [[email protected]] Sungwoo Park (Los Alamos National Laboratory) [[email protected]] Andrew Saunders (Los Alamos National Laboratory) [[email protected]] Boram Yoon (Los Alamos National Laboratory) [[email protected]] Albert Young (North Carolina State University) [[email protected]] Abstract: Exploring deviations from unitarity of the CKM matrix provides several probes of BSM physics. Many of these require calculating the matrix elements of the electroweak current between ground state mesons or nucleons, for which large scale simulations of lattice QCD provide the best systematically im- provable method. This LOI focues on improvments in the precision with which the CKM element jVudj can be extracted from neutron decay experiments coupled with lattice QCD calculations of the radiative correc- tions. -
UC San Diego UC San Diego Previously Published Works
UC San Diego UC San Diego Previously Published Works Title Neutron Lifetime Discrepancy as a Sign of a Dark Sector? Permalink https://escholarship.org/uc/item/5rw0t1wt Authors Fornal, Bartosz Grinstein, Benjamin Publication Date 2018-10-01 Peer reviewed eScholarship.org Powered by the California Digital Library University of California CIPANP2018-Fornal October 2, 2018 Neutron Lifetime Discrepancy as a Sign of a Dark Sector? Bartosz Fornal∗y and Benjam´ın Grinstein∗ Department of Physics University of California, San Diego 9500 Gilman Drive, La Jolla, CA 92093, USA We summarize our recent proposal of explaining the discrepancy between the bottle and beam measurements of the neutron lifetime through the ex- istence of a dark sector, which the neutron can decay to with a branching fraction 1%. We show that viable particle physics models for such neutron dark decays can be constructed and we briefly comment on recent develop- ments in this area. PRESENTED AT arXiv:1810.00862v1 [hep-ph] 1 Oct 2018 13th Conference on the Intersections of Particle and Nuclear Physics Palm Springs, CA, USA, May 29 { June 3, 2018 ∗ Research supported in part by the DOE Grant No. DE-SC0009919. y Speaker; talk title: Dark Matter Interpretation of the Neutron Decay Anomaly; based on: B. Fornal and B. Grinstein, Phys. Rev. Lett. 120, 191801 (2018) [1] 1 Neutron Lifetime In the Standard Model (SM), the dominant neutron decay channel is beta decay, − n ! p + e + νe ; (1) along with radiative corrections involving one or more photons in the final state. The theoretical prediction for the neutron lifetime is [2] SM 4908:7(1:9) s τn = 2 2 ; (2) jVudj (1 + 3gA) where gA is the ratio of the axial-vector to vector coupling. -
Ultracold Neutrons in Canada and Japan
Ultracold Neutrons in Canada and Japan Jeff Martin The University of Winnipeg February 2009 research supported by Natural Sciences and Engineering Research Council Canada Canada Foundation for Innovation Manitoba Research & Innovation Fund Japan Society for the Promotion of Science International Spallation Ultracold Neutron Source Spokespeople: Y. Masuda (KEK), J.W. Martin (Winnipeg) Collaborators: J.D. Bowman, J. Birchall, L. Buchmann, L. Clarke, C. Davis, B.W. Filippone, M. Gericke, R. Golub, K. Hatanaka, M. Hayden, T.M. Ito, S. Jeong, I. Kato, S. Komamiya, E. Korobkina, E. Korkmaz, L. Lee, K. Matsuta, A. Micherdzinska, W.D. Ramsay, S.A. Page, B. Plaster, I. Tanihata, W.T.H. van Oers, Y. Watanabe, S. Yamashita, T. Yoshioka (KEK, Winnipeg, Manitoba, ORNL, TRIUMF, NCSU, Caltech, RCNP, SFU, LANL, Tokyo, UNBC, Osaka, Kentucky) We propose to construct the world©s highest density source of ultracold neutrons and use it to conduct fundamental and applied physics research using neutrons. Ultracold Neutrons (UCN) ● What are UCN? ● Interactions of UCN. ● How to make UCN. ● Plans for the International Spallation Ultracold Neutron Source (i-SUN). ● Experiments that we would do there. Ultracold Neutrons (UCN) ● UCN are neutrons that are moving so slowly that they are totally reflected from a variety of materials. ● So, they can be confined in material bottles for long periods of time. ● Typical parameters: – velocity < 8 m/s = 30 km/h – temperature < 4 mK – kinetic energy < 300 neV ● Interactions: – gravity: V=mgh – weak interaction (allows UCN to decay) – magnetic fields: V=-µ •B – strong interaction Gravity ● Question: If I threw something straight up at an initial speed of 30 km/h, how high would it go? ● Answer (from high-school physics): – about 3 meters (10 feet).