Abstract. The most sensitive direct method to establish the absolute neutrino mass is observation of the endpoint of the tritium beta-decay spectrum. Cyclotron Radiation Emission Spectroscopy (CRES) is a precision spectrographic technique that can probe much of the unexplored neutrino mass range with O(eV) resolution. A lower bound of m(ν e ) 9(0.1) meV is set by observations of neutrino oscillations, while the KATRIN Experiment -the current-generation tritium beta-decay experiment that is based on Magnetic Adiabatic Collimation with an Electrostatic (MAC-E) filter -will achieve a arXiv:1703.02037v1 [physics.ins-det]

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments. For over a century, nuclear decay electron spectroscopy has played a pivotal role in the understanding of nuclear physics. Early measurements of the continuous β-decay spectrum [1] provided the first evidence of the existence of the weak force and the neutrino [2], and immediately hinted that the neutrino mass is small. Continuing this tradition, present efforts to directly measure the mass of the neutrino rely on precision spectroscopy of the β-decay energy spectrum of 3 H. Because the value of the neutrino mass is an input to the standard model of particle physics as well as precision cosmology, a precision measurement of the neutrino mass would represent a significant advance in our description of nature.The sensitivity of 3 H -based neutrino mass measurements has been improving over the past 80 years as a result of increasingly powerful electron spectrometry techniques [3][4][5][6]. The most sensitive experiments to date place a limit on the electron-flavor-weighted neutrino mass m β ≤ 2.05 eV=c 2 at 95% C.L. [7][8][9], m 2 β ¼

No abstract

The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory. The studied region includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A=135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations.