6 pages, 2 figures, for Proceedings of Carolina International Symposium on Neutrino Physics, Columbia, SC, May 15-17, 2008. To be published in J.Phys.: Conf. Series
The sum of the masses of the three neutrino mass eigenstates is now constrained both from above and below, and lies between 55 and 6900 meV. The lower limit is set by neutrino oscillations and the fact that masses are non-negative. The upper limit is set by laboratory measurements on the beta decay of tritium. These determinations share a common characteristic of being essentially model independent, or "direct." The clustering on large scales in the universe depends on this quantity, and, within the framework of Lambda-CDM cosmology, favors a mass sum below about 600 meV. In this article, the laboratory approach to neutrino mass via beta decay is emphasized, particularly an experiment now under construction, KATRIN, on the beta decay of tritium. Another candidate beta-active nuclide, Re-187, offers an advantage in phase space but calls for a very different experimental approach.
Measurement of the Cosmic Ray and Neutrino-Induced Muon Flux at the Sudbury Neutrino Observatory
本文报道了萨德伯里中微子天文台（SNO）运行1229天以来，在地球表面以下2公里深处测量大气中微子诱发μ介子通量的结果。通过测量作为天顶角函数的通过μ介子的通量，SNO实验可以区分中微子通量的振荡和非振荡部分。在$-1 \le \cosθ_{\rm zenith} \le 0.4$之间共测量到514个μ子样事件，总曝光量为2.30 \times 10^{14} $ cm$ ^{2} $ s. The measured flux normalization is $ 1.22 \pm 0.09 $ times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle $ \cos θ_{ \rm zenith} > 0.4 $ is mea…
We present a phenomenological study of nuclear effects in neutrino charged-current interactions, using transverse kinematic imbalances in exclusive measurements. Novel observables with minimal dependence on neutrino energy are proposed to study quasielastic scattering, and especially resonance production. They should be able to provide direct constraints on nuclear effects in neutrino- and antineutrino-nucleus interactions.
A precise prediction of the neutrino flux is a critical input for achieving the physics goals of accelerator-based neutrino experiments. In modern experiments, neutrino beams are created from the decays of secondary hadrons produced in hadron-nucleus interactions. Hadron production is the leading systematic uncertainty source on the neutrino flux prediction; therefore, its precise measurement is essential. In this proceedings, recent results and ongoing analyses of hadron production measurements by the NA61/SHINE experiment, as well as prospect for achievable precision on the flux predictions …
We present the most recent results from the two currently running solar neutrino experiments, Borexino at the Gran Sasso laboratory in Italy and SuperK at Kamioka mine in Japan. SuperK has released the most precise yet measurement of the 8B solar neutrino interaction rate, with a precision better than 2\%, consistent with a constant solar neutrino emission over more than a decade. Borexino has released refined measurements of all neutrinos produced in the pp fusion chain. For the first time, one single detector has measured the entire range of solar neutrinos at once. These new data weakly fav…
Neutrino interactions with nuclei have been the subject of intense interest over the last 15 years. Current and future measurements of neutrino oscillation and exotic physics use order 0.1--10 GeV neutrinos on a range of nuclear targets ($^{12}$C, $^{16}$O, $^{40}$Ar). As the precision of these experiments has increased, information from their detectors and dedicated experiments indicate deficiencies in the modeling of neutrino interactions on nuclear targets. Here, we present the current state of knowledge about neutrino-nucleus interactions, the challenge of extracting the cross section of t…
The Tokai to Kamioka (T2K) long-baseline neutrino experiment consists of a muon neutrino beam, produced at the J-PARC accelerator, a near detector complex and a large 295km distant far detector. The present work utilizes the T2K event timing measurements at the near and far detectors to study neutrino time of flight as function of derived neutrino energy. Under the assumption of a relativistic relation between energy and time of flight, constraints on the neutrino rest mass can be derived. The sub-GeV neutrino beam in conjunction with timing precision of order tens of ns provide sensitivity to…
We discuss the main limitations of past neutrino scattering experiments and possible ways to address them in a next-generation program of precision measurements of fundamental interactions with (anti)neutrinos. A reduction of the longstanding precision gap with respect to electron scattering experiments could provide interesting synergies with the existing efforts in the fixed-target, collider, and nuclear physics communities.
The modelling of neutrino nucleus interactions is one of the limiting systematic errors in long base line neutrino oscillation experiments. The accurate modelling of the neutrino interactions requires more experimental observables to determine its accuracy. Adler Angles are observables carrying information about the polarization of the ?Δ resonance and the interference with the non-resonant single pion production. These observables were measured with limited statistics in bubble chamber experiments. We discuss the possibility of measuring the angles in neutrino interactions with nucleus.
The MicroBooNE detector has recently completed its first year of neutrino beam data-taking in the Booster Neutrino Beam at Fermilab, having collected approximately half of its intended data ($3.4\times10^{20}$ of $6.6\times10^{20}$ protons on target). We present kinematic distributions of neutrino interactions observed from a small subset of this data (equivalent to $5\times10^{19}$ protons on target), both as a first step towards a charged-current muon neutrino cross-section on argon, and as an exploration of the capabilities and operational challenges of large liquid argon time projection ch…
A precise prediction of expected neutrino fluxes is required for a long-baseline accelerator neutrino experiment. The flux is used to measure neutrino cross sections at the near detector, while at the far detector it provides an estimate of the expected signal for the study of neutrino oscillations. In the talk several approaches to constrain the neutrino flux are presented. The first is the traditional one when an interaction chain for the neutrino parent hadrons is stored to be weighted later with real measurements. In this approach differential hadron cross sections are used which, in turn,…
The Karlsruhe Tritium Neutrino (KATRIN) experiment will provide a measurement of the effective electron-neutrino mass, $m(ν_e)$, based on a precision measurement of the tritium beta decay spectrum near its endpoint. The effective mass is an average of the neutrino mass eigenvalues $m_i$ weighted by the flavor-mass mixing parameters $U_{ei}$ according to the relation $m^2(ν_e)= \sum_{i=1}^3 |U_{ei} |^2 m_i^2$. The KATRIN apparatus uses a windowless gaseous tritium source (WGTS) and a spectrometer based on the MAC-E filter concept to measure the beta energy spectrum. The KATRIN program is design…
Neutrino magnetic moment effects in electron-capture measurements at GSI
我猜想，GSI的类氢重离子两体电子俘获衰变的单离子测量中所报道的时间调制衰变率可能与储存环静态磁场中的中微子自旋进动有关。这些“GSI振荡”产生于磁场内外衰变幅度之间的干扰，这种情况需要狄拉克中微子的磁矩比Borexino太阳中微子上限0.54 x 10 E（-10）玻尔磁子低六倍。我还以一种以前没有讨论过的方式表明，与大质量中微子振幅之间的干扰有关的时间调制，如果这种干扰可能出现的话，其周期至少比报道的短四个数量级，并且在给定GSI测量的时间分辨率的情况下，平均值必须为零。
