@article{gonzalez_fries_cude-woods_bailey_blatnik_broussard_callahan_choi_clayton_currie_et al._2021, title={Improved Neutron Lifetime Measurement with UCN τ}, volume={127}, ISSN={["1079-7114"]}, DOI={10.1103/PhysRevLett.127.162501}, abstractNote={We report an improved measurement of the free neutron lifetime τ_{n} using the UCNτ apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns in 2017 and 2018. We extract τ_{n} from three blinded, independent analyses by both pairing long and short storage time runs to find a set of replicate τ_{n} measurements and by performing a global likelihood fit to all data while self-consistently incorporating the β-decay lifetime. Both techniques achieve consistent results and find a value τ_{n}=877.75±0.28_{stat}+0.22/-0.16_{syst} s. With this sensitivity, neutron lifetime experiments now directly address the impact of recent refinements in our understanding of the standard model for neutron decay.}, number={16}, journal={PHYSICAL REVIEW LETTERS}, author={Gonzalez, F. M. and Fries, E. M. and Cude-Woods, C. and Bailey, T. and Blatnik, M. and Broussard, L. J. and Callahan, N. B. and Choi, J. H. and Clayton, S. M. and Currie, S. A. and et al.}, year={2021}, month={Oct}, pages={162501} }
 @article{kuk_cude-woods_chavez_choi_estrada_hoffbauer_holland_makela_morris_ramberg_et al._2021, title={Projection imaging with ultracold neutrons}, volume={1003}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2021.165306}, abstractNote={Ultracold neutron (UCN) projection imaging is demonstrated using a boron-coated back-illuminated CCD camera and the Los Alamos UCN source. Each neutron is recorded through the capture reactions with 10B. By direct detection at least one of the byproducts α, 7Li and γ (electron recoils) derived from the neutron capture and reduction of thermal noise of the scientific CCD camera, a signal-to-noise improvement on the order of 104 over the indirect detection has been achieved. Sub-pixel position resolution of a few microns is confirmed for individual UCN events. Projection imaging of test objects shows a spatial resolution less than 100μm by an integrated UCN flux one the order of 106 cm−2. The bCCD can be used to build UCN detectors with an area on the order of 1 m2. The combination of micrometer scale spatial resolution, low readout noise of a few electrons, and large area makes bCCD suitable for quantum science of UCN.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Kuk, K. and Cude-Woods, C. and Chavez, C. R. and Choi, J. H. and Estrada, J. and Hoffbauer, M. and Holland, S. E. and Makela, M. and Morris, C. L. and Ramberg, E. and et al.}, year={2021}, month={Jul} }
 @misc{phillips_snow_babul_banerjee_baxter_berezhiani_bergevin_bhattacharya_brooijmans_castellanos_et al._2016, title={Neutron-antineutron oscillations: Theoretical status and experimental prospects}, volume={612}, ISSN={["1873-6270"]}, DOI={10.1016/j.physrep.2015.11.001}, abstractNote={The observation of neutrons turning into antineutrons would constitute a discovery of fundamental importance for particle physics and cosmology. Observing the n–n̄ transition would show that baryon number (B) is violated by two units and that matter containing neutrons is unstable. It would provide a clue to how the matter in our universe might have evolved from the B=0 early universe. If seen at rates observable in foreseeable next-generation experiments, it might well help us understand the observed baryon asymmetry of the universe. A demonstration of the violation of B–L by 2 units would have a profound impact on our understanding of phenomena beyond the Standard Model of particle physics. Slow neutrons have kinetic energies of a few meV. By exploiting new slow neutron sources and optics technology developed for materials research, an optimized search for oscillations using free neutrons from a slow neutron moderator could improve existing limits on the free oscillation probability by at least three orders of magnitude. Such an experiment would deliver a slow neutron beam through a magnetically-shielded vacuum chamber to a thin annihilation target surrounded by a low-background antineutron annihilation detector. Antineutron annihilation in a target downstream of a free neutron beam is such a spectacular experimental signature that an essentially background-free search is possible. An authentic positive signal can be extinguished by a very small change in the ambient magnetic field in such an experiment. It is also possible to improve the sensitivity of neutron oscillation searches in nuclei using large underground detectors built mainly to search for proton decay and detect neutrinos. This paper summarizes the relevant theoretical developments, outlines some ideas to improve experimental searches for free neutron oscillations, and suggests avenues both for theoretical investigation and for future improvement in the experimental sensitivity.}, journal={PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS}, author={Phillips, D. G., II and Snow, W. M. and Babul, K. and Banerjee, S. and Baxter, D. V. and Berezhiani, Z. and Bergevin, M. and Bhattacharya, S. and Brooijmans, G. and Castellanos, L. and et al.}, year={2016}, month={Feb}, pages={1–45} }
 @article{brice_cooper_dejongh_empl_garrison_hime_hungerford_kobilarcik_loer_mariani_et al._2014, title={A method for measuring coherent elastic neutrino-nucleus scattering at a far off-axis high-energy neutrino beam target}, volume={89}, ISSN={1550-2368}, DOI={10.1103/physrevd.89.072004}, abstractNote={We present a new experimental method for measuring the process of Coherent Elastic Neutrino Nucleus Scattering (CENNS). This method uses a detector situated transverse to a high energy neutrino beam production target. This detector would be sensitive to the low energy neutrinos arising from pion decays-at-rest in the target. We discuss the physics motivation for making this measurement and outline the predicted backgrounds and sensitivities using this approach. We report a measurement of neutron backgrounds as found in an off-axis surface location of the Fermilab Booster Neutrino Beam (BNB) target. The results indicate that the Fermilab BNB target is a favorable location for a CENNS experiment.}, number={7}, journal={PHYSICAL REVIEW D}, author={Brice, S. J. and Cooper, R. L. and DeJongh, F. and Empl, A. and Garrison, L. M. and Hime, A. and Hungerford, E. and Kobilarcik, T. and Loer, B. and Mariani, C. and et al.}, year={2014}, month={Apr} }
 @article{salas-bacci_mcgaughey_baessler_broussard_makela_mirabal_pattie_pocanic_sjue_penttila_et al._2014, title={Characterization of large area, thick, and segmented silicon detectors for neutron beta-decay experiments}, volume={735}, journal={Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors, and Associated Equipment}, author={Salas-Bacci, A. and McGaughey, P. L. and Baessler, S. and Broussard, L. and Makela, M. F. and Mirabal, J. and Pattie, R. W. and Pocanic, D. and Sjue, S. K. L. and Penttila, S. I. and et al.}, year={2014}, pages={408–415} }
 @article{broussard_back_boswell_crowell_dendooven_giri_howell_kidd_jungmann_kruithof_et al._2014, title={Measurement of the Half-Life of the T=1/2 Mirror Decay of Ne-19 and its Implication on Physics Beyond the Standard Model}, volume={112}, ISSN={1079-7114}, DOI={10.1103/physrevlett.112.212301}, abstractNote={The $\frac{1}{2}^+ \rightarrow \frac{1}{2}^+$ superallowed mixed mirror decay of $^{19}$Ne to $^{19}$F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be $T_{1/2}$ = $17.2832 \pm 0.0051_{(stat)}$ $\pm 0.0066_{(sys)}$ s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.}, number={21}, journal={PHYSICAL REVIEW LETTERS}, author={Broussard, L. J. and Back, H. O. and Boswell, M. S. and Crowell, A. S. and Dendooven, P. and Giri, G. S. and Howell, C. R. and Kidd, M. F. and Jungmann, K. and Kruithof, W. L. and et al.}, year={2014}, month={May} }
 @article{pattie_hickerson_young_2013, title={Limits on tensor coupling from neutron beta decay}, volume={88}, ISSN={1089-490X}, DOI={10.1103/physrevc.88.048501}, abstractNote={Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\text{V}}=G_{\text{F}} V_{ud}$ as extracted from measurements of the $\mathcal{F}t$ values from the $0^{+} \to 0^{+}$ superallowed decays dataset. These limits are derived by comparing the neutron $\beta$-decay rate as predicted in the standard model with the measured decay rate while allowing for the existence of beyond the standard model couplings. We analyze limits derived from the electron-neutrino asymmetry, $a$, or the beta-asymmetry, $A$, finding that the most stringent limits for $C_\text{T}/C_\text{A}$ under the assumption of no right-handed currents is $-0.0026 < C_\text{T}/C_\text{A} < 0.0024$ (95% C.L.) for the two most recent values of $A$.}, number={4}, journal={PHYSICAL REVIEW C}, author={Pattie, R. W., Jr. and Hickerson, K. P. and Young, A. R.}, year={2013}, month={Oct} }
 @article{sharapov_morris_makela_saunders_adamek_bagdasarova_broussard_cude-woods_fellers_geltenbort_et al._2013, title={Measurements of ultracold neutron upscattering and absorption in polyethylene and vanadium}, volume={88}, ISSN={1089-490X}, DOI={10.1103/physrevc.88.037601}, abstractNote={The study of neutron cross sections for elements used as efficient ``absorbers'' of ultracold neutrons (UCN) is crucial for many precision experiments in nuclear and particle physics, cosmology and gravity. In this context, ``absorption'' includes both the capture and upscattering of neutrons to the energies above the UCN energy region. The available data, especially for hydrogen, do not agree between themselves or with the theory. In this report we describe measurements performed at the Los Alamos National Laboratory UCN facility of the UCN upscattering cross sections for vanadium and for hydrogen in CH$_2$ using simultaneous measurements of the radiative capture cross sections for these elements. We measured $\sigma_{up}=1972\pm130$ b for hydrogen in CH$_2$, which is below theoretical expectations, and $\sigma_{up} < 25\pm9$ b for vanadium, in agreement with the expectation for the neutron heating by thermal excitations in solids.}, number={3}, journal={PHYSICAL REVIEW C}, author={Sharapov, E. I. and Morris, C. L. and Makela, M. and Saunders, A. and Adamek, Evan R. and Bagdasarova, Y. and Broussard, L. J. and Cude-Woods, C. B. and Fellers, Deion E. and Geltenbort, Peter and et al.}, year={2013}, month={Sep} }
 @article{saunders_makela_bagdasarova_back_boissevain_broussard_bowles_carr_currie_filippone_et al._2013, title={Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source}, volume={84}, ISSN={0034-6748 1089-7623}, url={http://dx.doi.org/10.1063/1.4770063}, DOI={10.1063/1.4770063}, abstractNote={In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9) UCN/cc with a solid deuterium volume of ∼1500 cm3.}, number={1}, journal={Review of Scientific Instruments}, publisher={AIP Publishing}, author={Saunders, A. and Makela, M. and Bagdasarova, Y. and Back, H. O. and Boissevain, J. and Broussard, L. J. and Bowles, T. J. and Carr, R. and Currie, S. A. and Filippone, B. and et al.}, year={2013}, pages={013304} }
 @article{mendenhall_pattie_bagdasarova_berguno_broussard_carr_currie_ding_filippone_garcía_et al._2013, title={Precision measurement of the neutron<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>-decay asymmetry}, volume={87}, ISSN={0556-2813 1089-490X}, url={http://dx.doi.org/10.1103/physrevc.87.032501}, DOI={10.1103/physrevc.87.032501}, abstractNote={A new measurement of the neutron $\beta$-decay asymmetry $A_0$ has been carried out by the UCNA collaboration using polarized ultracold neutrons (UCN) from the solid deuterium UCN source at the Los Alamos Neutron Science Center (LANSCE). Improvements in the experiment have led to reductions in both statistical and systematic uncertainties leading to $A_0 = -0.11954(55)_{\rm stat.}(98)_{\rm syst.}$, corresponding to the ratio of axial-vector to vector coupling $\lambda \equiv g_A/g_V = -1.2756(30)$.}, number={3}, journal={Physical Review C}, publisher={American Physical Society (APS)}, author={Mendenhall, M. P. and Pattie, R. W. and Bagdasarova, Y. and Berguno, D. B. and Broussard, L. J. and Carr, R. and Currie, S. and Ding, X. and Filippone, B. W. and García, A. and et al.}, year={2013}, month={Mar} }
 @article{sharapov_morris_makela_saunders_adamek_broussard_cude-woods_fellers_geltenbort_hartl_et al._2013, title={Upscattering of ultracold neutrons from the polymer [C6H12](n)}, volume={88}, ISSN={1089-490X}, DOI={10.1103/physrevc.88.064605}, abstractNote={It is generally accepted that the main cause of ultracold neutron (UCN) losses in storage traps is the upscattering to the thermal energy range by hydrogen adsorbed on the surface of the trap walls. However, the data on which this conclusion is based are poor and contradictory. Here, we report a measurement, performed at the Los Alamos National Laboratory UCN source, of the average energy of the flux of upscattered neutrons after the interaction of UCN with hydrogen bound in semicrystalline polymer PMP (tradename TPX), [C$_{6}$H$_{12}$]$_n$. Our analysis, performed with the MCNP code based on the application of the neutron scattering law to UCN upscattered by bound hydrogen in semicrystalline polyethylene, [C$_{2}$H$_{4}$]$_n$, leads us to a flux average energy value of 26$\pm3$ meV in contradiction with previously reported experimental values of 10 to 13 meV and in agreement with the theoretical models of neutron heating implemented in the MCNP code.}, number={6}, journal={PHYSICAL REVIEW C}, author={Sharapov, E. I. and Morris, C. L. and Makela, M. and Saunders, A. and Adamek, Evan R. and Broussard, L. J. and Cude-Woods, C. B. and Fellers, Deion E. and Geltenbort, Peter and Hartl, M. and et al.}, year={2013}, month={Dec} }
 @article{holley_broussard_davis_hickerson_ito_liu_lyles_makela_mammei_mendenhall_et al._2012, title={A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment}, volume={83}, ISSN={0034-6748 1089-7623}, url={http://dx.doi.org/10.1063/1.4732822}, DOI={10.1063/1.4732822}, abstractNote={The UCNA collaboration is making a precision measurement of the β asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }=0.9985(4)$\end{document}ε¯=0.9985(4).}, number={7}, journal={Review of Scientific Instruments}, publisher={AIP Publishing}, author={Holley, A. T. and Broussard, L. J. and Davis, J. L. and Hickerson, K. and Ito, T. M. and Liu, C. Y. and Lyles, J. T. M. and Makela, M. and Mammei, R. R. and Mendenhall, M. P. and et al.}, year={2012}, pages={073505} }
 @article{plaster_rios_back_bowles_broussard_carr_clayton_currie_filippone_garcia_et al._2012, title={Measurement of the neutron beta-asymmetry parameter A(0) with ultracold neutrons}, volume={86}, number={5}, journal={Physical Review. C, Nuclear Physics}, author={Plaster, B. and Rios, R. and Back, H. O. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clayton, S. and Currie, S. and Filippone, B. W. and Garcia, A. and et al.}, year={2012} }
 @article{wrede_filippone_garcía_harper_lassell_liu_mendenhall_palmer_pattie_will_et al._2011, title={Preparation of 114mIn low energy conversion electron sources}, volume={269}, ISSN={0168-583X}, url={http://dx.doi.org/10.1016/j.nimb.2011.02.076}, DOI={10.1016/j.nimb.2011.02.076}, abstractNote={The preparation of ^(114)mIn sources of conversion electrons in the energy range 162–190 keV and β continuum with a 1989 keV endpoint via ion implantation of ^(113)In into Al substrates and subsequent irradiation by thermal and epi-thermal neutrons in a nuclear reactor is described}, number={10}, journal={Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, publisher={Elsevier BV}, author={Wrede, C. and Filippone, B.W. and García, A. and Harper, G.C. and Lassell, S. and Liu, J. and Mendenhall, M.P. and Palmer, A.S.C. and Pattie, R.W., Jr. and Will, D.I. and et al.}, year={2011}, month={May}, pages={1113–1116} }
 @article{rios_tatar_bacon_bowles_hill_green_hogan_ito_makela_morris_et al._2011, title={Sealed drift tube cosmic ray veto counters}, volume={637}, ISSN={0168-9002}, url={http://dx.doi.org/10.1016/J.NIMA.2010.12.098}, DOI={10.1016/j.nima.2010.12.098}, abstractNote={We describe a simple drift tube counter that has been used as a cosmic ray veto for the UCNA experiment, a first-ever measurement of the neutron beta-asymmetry using ultra-cold neutrons. These detectors provide an inexpensive alternative to more conventional scintillation detectors for large area cosmic ray anticoincidence detectors.}, number={1}, journal={Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors, and Associated Equipment}, publisher={Elsevier BV}, author={Rios, R. and Tatar, E. and Bacon, J.D. and Bowles, T.J. and Hill, R. and Green, J.A. and Hogan, G.E. and Ito, T.M. and Makela, M. and Morris, C.L. and et al.}, year={2011}, pages={105–108} }
 @article{liu_mendenhall_holley_back_bowles_broussard_carr_clayton_currie_filippone_et al._2010, title={Determination of the axial-vector weak coupling constant with ultracold neutrons}, volume={105}, number={18}, journal={Physical Review Letters}, author={Liu, J. and Mendenhall, M. P. and Holley, A. T. and Back, H. O. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clayton, S. and Currie, S. and Filippone, B. W. and et al.}, year={2010} }
 @article{pattie_anaya_back_boissevain_bowles_broussard_carr_clark_currie_du_et al._2009, title={First measurement of the neutron beta asymmetry with ultracold neutrons}, volume={102}, number={1}, journal={Physical Review Letters}, author={Pattie, R. W. and Anaya, J. and Back, H. O. and Boissevain, J. G. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clark, D. J. and Currie, S. and Du, S. and et al.}, year={2009} }
 @article{morris_bowles_gonzales_hill_hogan_makela_mortenson_ramsey_saunders_seestrom_et al._2009, title={Multi-wire proportional chamber for ultra-cold neutron detection}, volume={599}, ISSN={0168-9002}, DOI={10.1016/j.nima.2008.11.099}, abstractNote={In this paper we describe the principles that have guided our design and the experience we have gained building multi-wire proportional chambers detectors for the ultra-cold neutron (UCN) source at the Los Alamos Neutron Science Center (LANSCE). Simple robust detectors with 50 cm2 of active area have been designed. These have been used both in ion chamber and proportional mode for the detection of UCN.}, number={2-3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Morris, C. L. and Bowles, T. J. and Gonzales, J. and Hill, R. and Hogan, G. and Makela, M. and Mortenson, R. and Ramsey, J. and Saunders, A. and Seestrom, S. J. and et al.}, year={2009}, month={Feb}, pages={248–250} }