Snowmass Neutrino Frontier Report
This report summarizes the current status of neutrino physics and the broad and exciting future prospects identified for the Neutrino Frontier as part of the 2021 Snowmass Process.
arXiv subjects
Publications and source records attributed to Jonathan M. Link.
This report summarizes the current status of neutrino physics and the broad and exciting future prospects identified for the Neutrino Frontier as part of the 2021 Snowmass Process.
The non-linear energy response of the plastic scintillator EJ-260 is measured with the MicroCHANDLER detector, using neutron beams of energy 5 to 27 MeV at the Triangle Universities Nuclear Laboratory. The first and second order Birks' constants are extracted from the data, and found to be $k_B = (8.70 \pm 0.93)\times 10^{-3}\ {\rm g/cm^2/MeV}$ and $k_C = (1.42 \pm 1.00) \times 10^{-5}\ {\rm (g/cm^2/MeV)^2}$. This result covers a unique energy range that is of direct relevance for fast neutron backgrounds in reactor inverse beta decay detectors. These measurements will improve the energy non-linearity modeling of plastic scintillator detectors. In particular, the updated energy response model will lead to an improvement of fast neutron modeling for detectors based on the CHANDLER reactor neutrino detector technology.
The XENON1T experiment recently reported an excess of events at low electron recoil energies, which may be due to interactions of solar neutrinos inside the detector via a large neutrino magnetic moment. We point out that a $^{51}$Cr neutrino source placed close to the detector can directly test this hypothesis.
We deployed a small, 80kg, antineutrino detector based on solid plastic scintillator, called MiniCHANDLER for nearly three months at a distance of 25m from a 2.9GW thermal power reactor core at the North Anna Nuclear Generating Station. We report the detection of an antineutrino signal resulting from inverse beta decay at 5.5 sigma significance with no overburden and minimal shielding. This result also demonstrates that 3D segmentation can be used to significantly improve the signal to noise ratio, in this case by a factor of 4. In addition, this measurement represents an observation of the positron spectrum in a small, surface-deployed detector; this observation of reactor antineutrinos was achieved with a mobile neutrino detector mounted in an ordinary, small trailer.
Neutrino interactions beyond the Standard Model (BSM) are theoretically well motivated and have an important impact on the future precision measurement of neutrino oscillation. In this work, we study the sensitivity of a multi-ton-scale liquid Xenon dark matter detector equipped with an intense radiative neutrino source to various BSM neutrino-electron interactions. We consider the conventional Non-Standard Interactions (NSIs), other more generalized four-fermion interactions including scalar and tensor forms, and light-boson mediated interactions. The work shows that with realistic experimental setups, one can achieve unprecedented sensitivity to these BSM neutrino-electron interactions.
In this letter we point out the possibility to study new physics in the neutrino sector using dark matter detectors based on liquid xenon. These are characterized by very good spatial resolution and extremely low thresholds for electron recoil energies. When combined with a radioactive $ν_e$ source, both features in combination allow for a very competitive sensitivity to neutrino magnetic moments and sterile neutrino oscillations. We find that, for realistic values of detector size and source strength, the bound on the neutrino magnetic moment can be improved by an order of magnitude with respect to the present value. Regarding sterile neutrino searches, we find that most of the gallium anomaly could be explored at the 95% confidence level just using shape information.
We study the possibility to replace the anti-neutrino run of a long baseline neutrino oscillation experiment, with anti-neutrinos from muon decay at rest. The low energy of these neutrinos allows the use of inverse beta decay for detection in a Gadolinium-doped water Cerenkov detector. We show that this approach yields a factor of five times larger anti-neutrino event sample. The resulting discovery reaches in theta_13, the mass hierarchy and leptonic CP violation are compared with those from a conventional superbeam experiment with combined neutrino and anti-neutrino running. We find that this approach yields a greatly improved reach for CP violation and theta_13 while leaving the ability to measure the mass hierarchy intact.
We show that a low energy beta-beam facility can be used to search for sterile neutrinos by measuring the disappearance of electron anti-neutrinos. This channel is particularly sensitive since it allows to use inverse beta decay as detection reaction; thus it is free from hadronic uncertainties, provided the neutrino energy is below the pion production threshold. This corresponds to a choice of the Lorentz gamma=30 for the 6He parent ion. Moreover, a disappearance measurement allows the constraint of sterile neutrino properties independently of any CP violating effects. A moderate detector size of a few 100 tons and ion production rates of 2E13 per second are sufficient to constrain mixing angles as small as \sin^22θ=0.01 at 99% confidence level.
We report on a direct measurement of the mixing parameter y=(3.42+-1.39+-0.74)% in the D0-D0bar system by measuring the lifetime difference between the CP mixed final state K^+pi^- and the CP even state K^+K^-. We also present a study of the decay \ws based on a sample of 149+-31 observed events compared to 36760+-195 events observed in the Cabibbo favored channel D0->K^-pi^+. The observed branching ratio R=(0.404+-0.085+-0.025)% is used to obtain limits on the mixing parameters x' and y' and the doubly Cabibbo suppressed branching ratio, R_DCS. These studies are based on a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831).
Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay $D^0\to K^+π^-$ with a signal yield of $149\pm31$ events compared to a similarly cut sample consisting of $36760 \pm 195$ $D^0\to K^-π^+$ events. We use the observed ratio of $D^0\to K^+π^-$ to $D^0\to K^-π^+$ $(0.404\pm 0.085\pm 0.025)%$ to obtain a relationship between the $D^0$ mixing and doubly Cabibbo suppressed decay parameters.