Bulletin of the American Physical Society
2016 Fall Meeting of the APS Division of Nuclear Physics
Volume 61, Number 13
Thursday–Sunday, October 13–16, 2016; Vancouver, BC, Canada
Session HG: Mini-symposium on Neutron and Nuclear Tests of CKM Unitarity IIMini-Symposium
|
Hide Abstracts |
Chair: J.C. Hardy, Texas A&M University Room: Pavilion Ballroom B |
Saturday, October 15, 2016 8:30AM - 8:42AM |
HG.00001: CKM unitarity: a pion perspective Dinko Pocanic Whether or not the 3-generation Cabibbo--Kobayashi--Maskawa (CKM) quark mixing matrix is unitary has significant implications for the standard model of particles and fields (SM). Most importantly, the degree to which CKM unitarity is preserved sets limits on several important classes of physics extensions of the SM. Nuclear probes have played a key role in the most precise tests of the CKM top row unitarity. Among these, the beta decay of the charged pion, $\pi^{+} \to \pi^0e^{+}\nu_e$ offers the theoretically cleanest means to determine the dominant $V_{ud}$ CKM matrix element. We will examine the status, challenges and future prospects for $V_{ud}$ determination in the pion sector. [Preview Abstract] |
Saturday, October 15, 2016 8:42AM - 8:54AM |
HG.00002: Extraction of $a_1$ properties from hadronic tau decays Ina Lorenz, Emilie Passemar The axial vector current and its resonance content is a matter of debate. In particular the properties of the $a_1$ meson strongly depend on the model and experiment that is used to analyze tau decay data. We show the impact of physical constraints on these ambiguities using dispersion relations, and both structure functions and total decay rates. [Preview Abstract] |
Saturday, October 15, 2016 8:54AM - 9:06AM |
HG.00003: Improving Limits on Anomalous Pseudoscalar Interactions using Few Body Calculations Sheakha Aldaihan, William Michael Snow, Dennis Krause Exotic long-range spin-dependent interactions between nucleons can be generated by many possible sources beyond the Standard Model. Anomalous interactions arising from exchange of ultralight bosons with pseudoscalar couplings g$_{P}$ between free fermions are highly suppressed in the nonrelativistic limit due to their spin dependence and suppression factors associated with the parity change at the vertex. As a consequence the experimental limits on such interactions are several orders of magnitude weaker than limits on spin-independent Yukawa interactions. We call attention to a physical process in the interaction between nucleons in separate nuclei exchanging a light pseudoscalar first identified by Krause and Fischbach\footnote{Krause, D., et. al. (1993). Proceedings of the XXVIIIth Rencontre De Moriond. p.455.} which can lead to a spin independent effect and, in combination with existing experimental constraints on exotic Yukawa interactions, can improve constraints on g$_{P}$ for interaction ranges of atomic and mesoscopic scales. Similar nuclei models can also be used to improve constraints on P and T odd long-range interactions between scalar and pseudoscalar vertices.The theoretical evaluations of this effect will require knowledge of parity-odd matrix elements in nuclei. [Preview Abstract] |
Saturday, October 15, 2016 9:06AM - 9:18AM |
HG.00004: Searches for chirality-flipping interactions via cyclotron-radiation spectroscopy A. Garcia, M. Fertl, M. Guigue, P. Kammel, A. Leredde, P. Mueller, R.G.H. Robertson, G. Rybka, G. Savard, H.E. Swanson, B.A. Vandevender, A. Young The measurement of the beta spectrum from $^6{\rm He}$ allows for sensitive searches of tensor (chirality flipping) interactions. A source that delivers about $10^{10}$ $^6{\rm He}$ atoms per second in a stable fashion exists at the University of Washington. The recent demonstration by the Project 8 collaboration that detection of cyclotron radiation yields excellent energy resolution for electrons of $\lesssim 32$ keV emitted from a gaseous source invites application of the technique to higher-energy betas. Calculations and considerations showing the applicability of the technique for the $^6{\rm He}$ case will be presented. [Preview Abstract] |
Saturday, October 15, 2016 9:18AM - 9:30AM |
HG.00005: Precision experiments on mirror transitions at Notre Dame Maxime Brodeur Thanks to extensive experimental efforts that led to a precise determination of important experimental quantities of superallowed pure Fermi transitions, we now have a very precise value for Vud that leads to a stringent test of the CKM matrix unitarity. Despite this achievement, measurements in other systems remain relevant as conflicting results could uncover unknown systematic effects or even new physics. One such system is the superallowed mixed transition, which can help refine theoretical corrections used for pure Fermi transitions and improve the accuracy of Vud. However, as a corrected Ft-value determination from these systems requires the more challenging determination of the Fermi Gamow-Teller mixing ratio, only five transitions, spreading from 19Ne to 37Ar, are currently fully characterized. To rectify the situation, an experimental program on precision experiment of mirror transitions that includes precision half-life measurements, and in the future, the determination of the Fermi Gamow-Teller mixing ratio, has started at the University of Notre Dame. [Preview Abstract] |
Saturday, October 15, 2016 9:30AM - 9:42AM |
HG.00006: Status of the TAMUTRAP facility at Texas A\&M University Dan Melconian, Eames Bennett, Michael Mehlman, John Patti, Praveen Shidling The Cyclotron Institute at Texas A\&M University is nearing completion of an upgrade to recommission our K150 cyclotron and couple it to our K500 cyclotron, allowing the two to either work in parallel or together for re-acceleration of exotic ions. One of the end-stations being constructed to take advantage of the high intenstities available from the K150 is T{\small AMU}T{\small RAP}: a 180-mm inner diameter cylindrical Penning trap. The unprecedented open-area of T{\small AMU}T{\small RAP} is ideal for $4\pi$ collection of the delayed protons following the superallowed $\beta$ decays of proton-rich nuclei. In particular, observation of the $\beta$-delayed proton in coincidence with the $\beta$ can be used to determine the $\beta-\nu$ correlation parameter, the value of which can be used as a sensitive probe of possible scalar currents contributing to the weak interaction.\\ An overview of the correlation experiments planned at T{\small AMU}T{\small RAP} as well as its current status will be presented. [Preview Abstract] |
Saturday, October 15, 2016 9:42AM - 9:54AM |
HG.00007: Neutralizer for TRIUMF's experiment for measurements of parity non-conservation in francium Alexandre Gorelov, J.A. Behr, M.R. Kalita, M.R. Pearson, M, Tandecki, D. l, S. Aubin, R. Collister, A.C. DeHart, G. Gwinner, E. Gomez, L.A. Orozco, J. z The experiment at TRIUMF for measurements of parity non-conservation (PNC) effects in magneto-optically trapped (MOT) isotopes of francium to test the Standard Model at low energies underwent significant development. In particular, we have overhauled the design of the neutralizer, which catches ionized atoms from the ISAC radioactive beam facility and releases them in neutral form for trapping. We have adopted the design idea, proposed by group of researchers from State University of New York, Stony Brook. It assumed sequential collecting of radioactive species on cold foil, transport them to capture cell and release during short time heating of the foil. We have modified original electric connections to the foil, the way of mounting foil and replaced yttrium foil by zirconium one, more robust. Such modifications allowed us to ensure an operation of the neutralizer through more than 500,000 cycles (this makes possible continuous taking of data during 2 months) with the release about 10\% of embedded atoms per cycle. [Preview Abstract] |
Saturday, October 15, 2016 9:54AM - 10:06AM |
HG.00008: Precision measurement of the nuclear polarization of laser-cooled, optically pumped 37K J.A. Behr, I. Craiciu, A. Gorelov, S. Smale, C.L. Warner, L. Lawrence, B. Fenker, R.S. Behling, M. Mehlman, D. Melconian, G. Gwinner, M. Anholm, J. McNeil, D. Ashery, I. Cohen We have spin-polarized laser cooled $^{37}$K by direct optical pumping and measured the polarization to $<$ 0.1\% accuracy [B. Fenker arXiv:1602.04526]. Our polarization method naturally monitors the polarization of the nuclei as they decay. The atoms absorb circularly polarized light directed along the quantization axis near-resonant with the atomic S$_{1/2}$ to P$_{1/2}$ transition. Once the atoms are polarized, they stop absorbing light, so the ratio between the final P$_{1/2}$ population and its initial maximum probes the degree of polarization. We monitor the P$_{1/2}$ population using UV photons energetic enough to photoionize the P$_{1/2}$ state but not the S$_{1/2}$ state. Since the final P$_{1/2}$ population nearly vanishes, 5\% precision on the final/maximum ratio determines the polarization to 0.1\%. We eliminate a nonclassical effect, coherent population trapping, which could produce poorly polarized unexcited atoms. We show planned upgrades. Our result for the nuclear vector polarization during our A$_\beta$ measurement [B. Fenker, this conference] was 99.13(9)\%, not the dominant systematic. [Preview Abstract] |
Saturday, October 15, 2016 10:06AM - 10:18AM |
HG.00009: A high-precision measurement of the $\pi \rightarrow e \nu$ branching ratio} TRISTAN SULLIVAN, D.A. Bryman, S. Cuen-Rochin, A. Aguilar-Arevalo, M. Aoki, M. Blecher, D.I. Britton, D. Protopopescu, D. Vom Bruch, S. Chen, J. Comfort, L. Doria, P. Gumplinger, L. Kurchaninov, R.E. Mischke, T. Numao, A. Sher, D. Vavilov, A. Hussein, Y. Igarashi, . Kek, S. Ito, S.H. Kettell, L.S. Littenberg, C. Malbrunot The pion decay branching ratio, $ R_{\pi} = \frac{\Gamma\left(\pi \rightarrow e \nu \hspace{1 mm} + \hspace{1 mm} \pi \rightarrow e \nu \gamma \right)}{\Gamma\left(\pi \rightarrow \mu \nu \hspace{1 mm} + \hspace{1 mm} \pi \rightarrow \mu \nu \gamma \right)}$, is an important observable in the Standard Model of particle physics. The value of the $\pi \rightarrow e \nu$ branching ratio has been calculated within the Standard Model to be (1.2352 $\pm$ 0.0002) $\times 10^{-4}$. The PIENU experiment at TRIUMF aims to measure this quantity to a precision of $<$ 0.1\%. This provides a sensitive test of lepton universality, and constraints on many new physics scenarios with mass reach up to 1000 TeV. The measurements are also sensitive to the presence of heavy neutrinos.The current state of the analysis of the PIENU data will be presented. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700