Constraints on Unparticles from Low Energy Neutrino-Electron Scattering

We place limits on scalar and vector unparticle couplings to electrons and neutrinos using data from reactor neutrino experiments originally designed to search for neutrino magnetic moment. Upper bounds on Standard Model lepton-scalar unparticle and lepton-vector unparticle couplings $\lambda_0$, and $\lambda_1$ are given for various values of the unparticle mass dimension d, and the unparticle energy scale $\Lambda_{\cal U}$. Especially for smaller values of the mass dimension d (1 <d <1.3) these bounds are very significant and comparable to those obtained from production rates at high energy colliders. These bounds are also similar to those obtained by the analysis of the absence of the decay of the low-energy solar and reactor neutrinos.Comment: 6 pages of LATEX, 3 figure

Fermionic Effective Operators and Higgs Production at a Linear Collider

We study the possible contributions of dimension six operators containing fermion fields to Higgs production at a 500 GeV or 1 TeV $e^+e^-$ linear collider. We show that -- depending on the production mechanism -- the effects of such operators can be kinematically enhanced relative to Standard Model (SM) contributions. We determine constraints on the operator coefficients implied by existing precision electroweak measurements and the scale of neutrino mass. We find that even in the presence of such constraints, substantial deviations from SM Higgs production cross-sections are possible. We compare the effects of fermionic operators with those associated with purely bosonic operators that have been previously discussed in the literature.Comment: 25 pages, 9 figures, fixed typo in author name

Prospects for measuring coherent neutrino-nucleus elastic scattering at a stopped-pion neutrino source

Rates of coherent neutrino-nucleus elastic scattering at a high-intensity stopped-pion neutrino source in various detector materials (relevant for novel low-threshold detectors) are calculated. Sensitivity of a coherent neutrino-nucleus elastic scattering experiment to new physics is also explored.Comment: 9 pages, 14 figures; minor modifications for publicatio

Neutrino Mass Implications for Muon Decay Parameters

We use the scale of neutrino mass to derive model-independent naturalness constraints on possible contributions to muon decay Michel parameters from new physics above the electroweak symmetry-breaking scale. Focusing on Dirac neutrinos, we obtain a complete basis of effective dimension four and dimension six operators that are invariant under the gauge symmetry of the Standard Model and that contribute to both muon decay and neutrino mass. We show that -- in the absence of fine tuning -- the most stringent bounds on chirality-changing operators relevant to muon decay arise from one-loop contributions to neutrino mass. The bounds we obtain on their contributions to the Michel parameters are four or more orders of magnitude stronger than bounds previously obtained in the literature. We also show that there exist chirality-changing operators that contribute to muon decay but whose flavor structure allows them to evade neutrino mass naturalness bounds. We discuss the implications of our analysis for the interpretation of muon decay experiments.Comment: 19 pages, 4 figure

Geological controls on radon potential in Northern Ireland

Moderate and high radon potential in Northern Ireland is associated mainly with (i) the Neoproterozoic psammites, semipelites, meta-limestones, volcanics and mafic intrusives of Counties Londonderry and Tyrone; (ii) Silurian Hawick Group greywackes and, to a much more limited extent Gala Group greywackes, in the southern sector of Counties Armagh and Down; (iii) Ordovician and Silurian acid intrusives and volcanics in eastern Counties Londonderry and Tyrone; (iv) Middle-Late Devonian conglomerates in County Tyrone; (v) Lower Carboniferous (Dinantian) limestone in the western sector of Northern Ireland, especially in County Fermanagh; (vi) Palaeogene and Late Caledonian acid intrusive rocks of the Mourne Mountains Complex, Slieve Gullion Complex and Newry Granodiorite Complex in the SE sector in County Down and County Armagh. Moderate to high radon potential is sometimes associated with glacio-fluvial sand and gravel deposits where these overlie a range of bedrocks, some of which have relatively low radon potential. In this latter case the enhanced radon potential is probably caused by the high permeability of superficial deposits. Radon potential tends to be lower when bedrocks characterised by moderate or high radon potential are overlain by relatively impermeable silt-clay alluvium, glaciolacustrine, and lacustrine deposits; peat; and glacial till and moraine. Redistribution of rock debris derived from uranium-rich bedrocks, such as the Mourne Mountains granites, through glacial, alluvial and other processes can also result in higher radon potential being associated with superficial deposits relative to underlying bedrock

Electromagnetic Leptogenesis

We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.Comment: 6 pages, 6 figures; v2: some references added, minor change to discussion, accepted by PR

New gas mixtures suitable for rare event detection using a Micromegas-TPC detector

The aim of the presented work was to develop further techniques based on a Micromegas-TPC, in order to reach a high gas gain with good energy resolution, and to search for gas mixtures suitable for rare event detection. This paper focuses on xenon, which is convenient for the search of neutrinoless double beta decay in 136 Xe. Conversely, a small admixture of xenon to CF 4 can reduce attachment in the latter. This gas mixture would be suitable for dark matter searches and the study of solar and reactor neutrinos. Various configurations of the Micromegas plane were investigated and are described.Comment: 14 pages, 8 figures, article, revised version with improved figures, text modifications, accepted for publication by JINS

Does the neutrino magnetic moment have an impact on solar neutrino physics?

Solar neutrino observations coupled with the recent KamLAND data suggest that spin-flavor precession scenario does not play a major role in neutrino propagation in the solar matter. We provide approximate analytical formulas and numerical results to estimate the contribution of the spin-flavor precession, if any, to the electron neutrino survival probability when the magnetic moment and magnetic field combination is small.Comment: 7 pages, 1 figure

Unparticle physics and neutrino phenomenology

We have constrained unparticle interactions with neutrinos and electrons using available data on neutrino-electron elastic scattering and the four CERN LEP experiments data on mono photon production. We have found that, for neutrino-electron elastic scattering, the MUNU experiment gives better constraints than previous reported limits in the region d>1.5. The results are compared with the current astrophysical limits, pointing out the cases where these limits may or may not apply. We also discuss the sensitivity of future experiments to unparticle physics. In particular, we show that the measurement of coherent reactor neutrino scattering off nuclei could provide a good sensitivity to the couplings of unparticle interaction with neutrinos and quarks. We also discuss the case of future neutrino-electron experiments as well as the International Linear Collider.Comment: 20 pages, 5 figures. Minor changes, final versio

Low energy tracking and particles identification in the MUNU Time Projection Chamber at 1 bar. Possible application in low energy solar neutrino spectroscopy

In this paper we present the results from the measurements made with the MUNU TPC at 1bar pressure of CF4 in the energy region below 1 MeV. Electron events down to 80 keV are successfully measured. The electron energy and direction are reconstructed for every contained single electron above 200 keV. As test the 137Cs photopeak is reconstructed by measuring both the energy and direction of the Compton electrons in the TPC.Comment: 19 pages, 9 figures (6 figures in color); Figure 10 has been deleted from [v1]. Additional paragraph has been included; Manuscript is submitted to Nuclear Inst. and Methods in Physics Research,