Bulletin of the American Physical Society
2010 Fall Meeting of the APS Division of Nuclear Physics
Volume 55, Number 14
Tuesday–Saturday, November 2–6, 2010; Santa Fe, New Mexico
Session HC: Fundamental Symmetries Theory and Experiment |
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Chair: Scott Wilburn, Los Alamos National Laboratory Room: Sweeny C |
Friday, November 5, 2010 10:30AM - 10:42AM |
HC.00001: Neutron storage time measurement for the neutron EDM experiment W. Clark Griffith, Takeyasu Ito, John Ramsey, Mark Makela, Steven Clayton, Raul Hennings-Yeomans, M. Saidur Rahaman, Scott Currie, Todd Womack, Walter Sondheim, Martin Cooper A new experiment to search for the neutron electric dipole moment (nEDM) is under development for installation at the Spallation Neutron Source (SNS) at Oakridge National Laboratory. The experiment will use ultra-cold neutrons (UCN) stored in superfluid helium, along with $^3$He atoms acting as a neutron spin analyzer and comagnetometer. One crucial factor affecting the ultimate sensitivity of the experiment is the neutron storage time that can be obtained in the acrylic measurement cell. The acrylic cell walls will be coated with deuterated polystyrene (dPS), which is expected to give a wall loss factor of $\sim < 10^{-5}$ per bounce when cooled below the point where upscattering by hydrogen impurities contribute to UCN losses. We are currently preparing a measurement at Los Alamos to verify that a $10^{-5}$ wall loss factor can be achieved in a dPS coated acrylic test cell. The planned measurement will investigate the temperature dependence of the UCN storage time in the dPS coated test cell between room temperature and below 20 K. [Preview Abstract] |
Friday, November 5, 2010 10:42AM - 10:54AM |
HC.00002: Precise Half-Life Measurement of $^{46}$V H.I. Park, J.C. Hardy, V.E. Iacob, L. Chen, J. Goodwin, N. Nica, E. Simmons, L. Trache, R.E. Tribble The $^{46}$V is one of the key superallowed transitions contributing to precision tests of the conserved vector current hypothesis and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. Recent Penning-trap $Q_{EC}$ measurements of the superallowed $\beta$ decay of $^{46}$V showed an earlier reaction-based result to be wrong and raised the $Ft$ value by nearly three standard deviations from the average of all other well-known superallowed transitions. This anomaly raised the possibility of systematic effects for all reaction-based $Q$- value measurements and led to a theoretical reexamination of the isospin-symmetry-breaking corrections for superallowed decays. The improved corrections removed the anomalous result of $^{46}$V and restored agreement among the corrected $Ft$ values. Throughout these changes, the previously accepted half- life of $^{46}$V was assumed to be completely correct. We have now tested this assumption by measuring a new precise half-life of $^{46}$V. The preliminary result, 422.67(10) ms, agrees with but is more precise than previous values. [Preview Abstract] |
Friday, November 5, 2010 10:54AM - 11:06AM |
HC.00003: Tracing remnants of the baryon vector current anomaly in $n\to p e^- \bar\nu_e \gamma$ Daheng He, Susan Gardner We show that a triple-product correlation in the neutron radiative $\beta$-decay rate, characterized by the kinematical variable ${\mathbf l}_p\cdot({\mathbf l}_e\times{\mathbf k})$, isolates the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and SU(2)$\times$U(1) gauge invariance at low energies. We consider the bound which emerges on the strength of its neutral current analogue from MiniBooNE data and compute the size of the expected asymmetry in $n\to p e^- \bar\nu_e \gamma$. [Preview Abstract] |
Friday, November 5, 2010 11:06AM - 11:18AM |
HC.00004: Do Radioactive Half-Lives Depend on the Earth-Sun Distance? John Goodwin, John Hardy, Victor Iacob, Victor Golovko In recent articles [1-4], Jenkins \textit{et al}. claim to have evidence that radioactive half-lives vary as a function of the earth-to-sun distance. They base their claims on data obtained by others over the space of several years -- the decay of $^{32}$Si as measured at Brookhaven National Laboratory [5] from 1982-85 and that of $^{226}$Ra as measured at the Physikalisch Technische Bundesanstalt in Germany [6] from 1984-88 -- in which the decay rates show a small but statistically significant oscillation with a period of one year and approximately correlated with the earth-sun distance (and with the seasons). Here we report a series of seven measurements of the $^{198}$Au half-life (see [7] for a description of two of these) made by us at various intervals over a period of one aphelion-aphelion cycle. Each measured half-life has a precision of about 0.02{\%}. There is no evidence of any deviation from a constant half-life. [1] J. H. Jenkins \textit{et al}., Astropart. Phys. \textbf{31} 407 (2009) [2] J. H. Jenkins \textit{et al}., Astropart. Phys. \textbf{32}, 42 (2010) [3] E. Fischbach \textit{et al}., Space Sci. Rev. \textbf{145}, 285 (2009) [4] J. Jenkins \textit{et al}., arxiv:0912:5385v1 [5] D. Alburger \textit{et al}., Earth and Planet. Sci. Lett. \textbf{78}, 168 (1986) [6] H. Siegert \textit{et al}., Appl. Radiat. Isot.\textbf{ 49}, 1397 (1998) [7] J. R. Goodwin \textit{et al}., Eur. Phys. J. A \textbf{34}, 271 (2007). [Preview Abstract] |
Friday, November 5, 2010 11:18AM - 11:30AM |
HC.00005: A Trek to TREK Michael Kohl The Time Reversal Experiment with Kaons (TREK) at J-PARC has been designed to find New Physics beyond the Standard Model through the T-violating transverse polarization $P_T$ of muons in the $K^{+}_{\mu3}$ decay of stopped kaons with a sensitivity of $10^{-4}$, which is more than 20 times the sensitivity of its predecessor experiment E-246 at KEK-PS. TREK will use a high-intensity kaon beam and the upgraded E-246 apparatus. Two preceding measurements to use part of the new apparatus during the initial low-intensity phase at J-PARC are being proposed, to test lepton universality in the $K_{e2}/K_{\mu2}$ ratio, and to search for heavy sterile neutrinos. An overview of the planned experiments, results from recent R\&D activities, and the current project status will be presented. [Preview Abstract] |
Friday, November 5, 2010 11:30AM - 11:42AM |
HC.00006: New Results on the Hadronic Tau Decay Determination of $\alpha_s$ Kim Maltman Finite energy sum rule (FESR) analyses of non-strange hadronic $\tau$ decay data provide one of the most precise determinations of the strong coupling constant, $\alpha_s$. Over the last two years, analyses of the relevant current-current two-point functions based on the recently derived 5-loop result for the relevant $D=0$ OPE contributions have reached a nominal precision of order $1\%$, and brought the resulting determination of $\alpha_s(M_Z^2)$ into excellent agreement with independent lattice results. An outstanding issue for the FESR analyses is the possibility of residual ``duality violation'', i.e. of contributions associated with the breakdown of the OPE in the vicinity of the timelike real invariant-squared-mass axis. In this talk I discuss recent work to investigate and quantify these effects and present results for the impact of such contributions on the determination of $\alpha_s$, as well as on the determination of the $D=6$ condensates appearing in the OPE representation of the non-strange vector minus axial vector correlator difference, which condensates are relevant to determining the chiral limit values of the $K\rightarrow\pi\pi$ matrix elements of the electroweak penguin operators in the Standard Model.The reported analysis also provides a new determination of the gluon condensate. [Preview Abstract] |
Friday, November 5, 2010 11:42AM - 11:54AM |
HC.00007: Fully ElectroStatic Ion Traps for $\beta$-decay Studies Guy Ron Using principles analogous to those of conventional optics it is possible to construct fully electrostatic ion traps which act as a resonant cavity for ion beams. Such traps exhibit an unexpected phenomenon of self-bunching which allows for long lifetimes of trapped ion bunches. Such a trap was originally conceived and developed at the Weimann Institute of Science. Based on this design we are constructing such a trap for use with the LBL IRIS beamline. I will present the principles and design of such a trap. I will further discuss the experimental possibilities afforded, with emphasis on mass spectroscopy and possible measurements of $\beta$ decay correlations of trapped radioactive ions. Such measurements allow the study of possible standard model extensions affecting the structure of the weak interaction. [Preview Abstract] |
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