The Cosmic Ray Muon Flux at WIPP

In this work a measurement of the muon intensity at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM, USA is presented. WIPP is a salt mine with a depth of 655 m. The vertical muon flux was measured with a two panels scintillator coincidence setup to Phi_{vert}=3.10(+0.05/-0.07)*10^(-7)s^(-1)cm^(-2)sr^(-1).Comment: 18 pages, p figure

A next generation measurement of the electric dipole moment of the neutron at the FRM II

In this paper we discuss theoretical motivations and the status of experimental searches to find time-reversal symmetry-violating electric dipole moments (EDM). Emphasis is given to a next generation search for the EDM of the neutron, which is currently being set up at the FRM II neutron source in Garching, with an ultimate sensitivity goal of 5 × 10−28 cm (3σ). The layout of the apparatus allows for the detailed investigation of systematic effects by combining various means of magnetic field control and polarized UCN optics. All major components of the installations are portable and can be installed at the strongest available UCN beam

Mechanistic insight into proton-coupled mixed valency

Stabilisation of the mixed-valence state in [Mo2(TiPB)3(HDOP)]2+ (HTiPB = 2,4,6-triisopropylbenzoic acid, H2DOP = 3,6-dihydroxypyridazine) by electron transfer (ET) is related to the proton coordinate of the bridging ligands. Spectroelectrochemical studies suggest that ET is slower than 109 s−1. The mechanism has been probed using DFT calculations, which show that proton transfer induces a larger dipole in the molecule resulting in ET

First Measurement of the Neutron β\beta-Asymmetry with Ultracold Neutrons

We report the first measurement of angular correlation parameters in neutron $\beta$-decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for $\sim 30$ s in a Cu decay volume. The $\vec{\mu}_n \cdot \vec{B}$ potential of a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage (AFP) spin-flipper and enter a decay volume, situated within a 1 T, $2 \times 2\pi$ superconducting solenoidal spectrometer. We determine a value for the $\beta$-asymmetry parameter $A_0$, proportional to the angular correlation between the neutron polarization and the electron momentum, of $A_0 = -0.1138 \pm 0.0051$.Comment: 4 pages, 2 figures, 1 table, submitted to Phys. Rev. Let

Final results for the neutron β-asymmetry parameter A₀ from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A₀

Options for the Neutron Lifetime Measurements in Traps

Different geometries for the neutron lifetime measurements by the method of ultracold neutron storage in material traps and additional possibilities for the neutron storage in the magnetic storage ring are considered.Comment: 21 p., 11 figure

Overview of the CKM Matrix

The current status of the determination of the elements of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix is reviewed. Tensions in the global fits are highlighted. Particular attention is paid to progress in, and prospects for, measurements of CP violation effects.Comment: Proceedings of the Lepton Photon 2011 Conference, to appear in "Pramana - journal of physics", 17 pages, 13 figure