Measurement Of Neutrino Mass Research Articles

Toward the measurement of neutrino masses: Performance of cosmic magnification with submillimeter galaxies

Context. The phenomenon of magnification bias can induce a non-negligible angular correlation between two samples of galaxies with nonoverlapping redshift distributions. This signal is particularly clear when background submillimeter galaxies are used, and has been shown to constitute an independent cosmological probe. Aims. This work extends prior studies on the submillimeter galaxy magnification bias to the massive neutrino scenario, with the aim being to assess its sensitivity as a cosmological observable to the sum of neutrino masses. Methods. The measurements of the angular cross-correlation function between moderate redshift GAMA galaxies and high-redshift submillimeter H-ATLAS galaxies are fit to the weak lensing prediction down to the arcmin scale. The signal is interpreted under the halo model, which is modified to accommodate massive neutrinos. We discuss the impact of the choice of cosmological parametrization on the sensitivity to neutrino masses. Results. The currently available data on the magnification bias affecting submillimeter galaxies are sensitive to neutrino masses when a cosmological parametrization in terms of the primordial amplitude of the power spectrum (As) is chosen over the local root mean square of smoothed linear density perturbations (σ8). A clear upper limit on the sum of neutrino masses can be derived if the value of As is either fixed or assigned a narrow Gaussian prior, a behavior that is robust against changes to the chosen value.

Improved treatment of the T2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document} molecular final-states uncertainties for the KATRIN neutrino-mass measurement

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective mass of the electron antineutrino via a high-precision measurement of the tritium β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upbeta $$\\end{document}-decay spectrum in its end-point region. The target neutrino-mass sensitivity of 0.2eV/c2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${0.2}~\ ext {eV}/\ ext {c}^2$$\\end{document} at 90% CL can only be achieved in the case of high statistics and good control of the systematic uncertainties. One key systematic effect originates from the calculation of the molecular final states of T2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_2$$\\end{document}β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upbeta $$\\end{document} decay. In the first neutrino-mass analyses of KATRIN the contribution of the uncertainty of the molecular final-states distribution (FSD) was estimated via a conservative phenomenological approach to be 2×10-2eV2/c4.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2 \ imes 10^{-2}~\ ext {eV}^{2}/\ ext {c}^{4}.$$\\end{document} In this work a new procedure is presented for estimating the FSD-related uncertainties by considering the details of the final-states calculation, i.e. the uncertainties of constants, parameters, and functions used in the calculation as well as its convergence itself as a function of the basis-set size used in expanding the molecular wave functions. The calculated uncertainties are directly propagated into the experimental observable, the squared neutrino mass mν2,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_\ u ^2,$$\\end{document} and thus have to be determined individually for each experimental configuration. For the experimental conditions of the first KATRIN measurement campaign the new procedure is presented in detail, allowing for the application of this procedure to other experiments. This specific calculation leads to a constraint of the FSD-related uncertainty of 1.3×10-3eV2/c4,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1.3 \ imes 10^{-3}~\ ext {eV}^{2}/\ ext {c}^{4},$$\\end{document} well below the design limit of 7.5×10-3eV2/c4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$7.5 \ imes 10^{-3}~\ ext {eV}^{2}/\ ext {c}^{4}$$\\end{document} for any individual systematic contribution.

Neutrino mass measurement with cosmic gravitational focusing

We thoroughly explore the cosmic gravitational focusingof cosmic neutrino fluid (CνF) by dark matter (DM) halousing both general relativity for a pointsource of gravitational potential and Boltzmannequations for continuous overdensities. Derived inthe general way for both relativistic andnon-relativistic neutrinos, our resultsshow that the effect has fourth powerdependence on the neutrino mass and temperature.With nonlinear mass dependence which is differentfrom the cosmic microwave background (CMB) andlarge scale structure (LSS) observations,the cosmic gravitational focusing can provide anindependent cosmological way of measuring the neutrinomass and ordering. We take DESI as an example toillustrate that the projected sensitivity as well as itssynergy with existing terrestrial neutrino oscillationexperiments and other cosmological observations cansignificantly improve the neutrino mass measurement.

The minimal massive Majoron Seesaw Model

A convincing explanation of the smallness of neutrino masses is represented by the Type-I Seesaw mechanism, where the two measured neutrino mass differences can be generated by introducing at least two right-handed neutrinos. In an ultraviolet complete model, it is possible to dynamically generate the heavy Majorana scale through the spontaneous symmetry breaking of a global Abelian symmetry and the most economical realisation consists in coupling the two exotic neutral leptons to a singlet complex scalar field. The associated Goldstone boson is often dubbed as Majoron, which may achieve a non-vanishing mass by means of a small term that explicitly breaks the Abelian symmetry. In a generic model, the neutrino and Majoron mass generation mechanisms are completely uncorrelated. In this paper, instead, we reduce the landscape of possible models proposing a unique, minimal and predictive framework in which these two types of masses are strictly tied and arise from the same source. Bounds from various terrestrial and astrophysical experiments are discussed.

Neutrino mass sum rules from modular A4 symmetry

Modular symmetries offer a dynamic approach to understanding the flavor structure of leptonic mixing. Using the modular A4 flavor symmetry integrated in a type-II seesaw, we propose a simple and minimalistic model that restricts the neutrino oscillation parameter space and, most importantly, introduces a sum rule in the physical neutrino masses. When combined with the mass squared differences observed in neutrino oscillations, this sum rule determines the absolute neutrino mass scale. This has significant implications for cosmology, neutrinoless double beta decay experiments, and direct neutrino mass measurements. In particular, the model predicts ∑imi≈0.1 eV for both normal and inverted ordering, and thus can be fully probed by the current generation of cosmological probes in the upcoming years. Published by the American Physical Society 2024

Measuring neutrino mass and asymmetry with matter pairwise velocities

ABSTRACT Neutrinos are believed to be the most abundant fermions in the Universe, but their masses are unknown, except for being non-zero but much smaller than other fermions. Cosmological relic neutrinos could also have non-zero chemical potentials (or asymmetries). Using neutrino-involved N-body simulations, we investigate the neutrino effects on the matter pairwise velocity, which itself is an interesting probe of cosmology. We find that for light-halo ([1011, 1013] M⊙) mean pairwise velocity, in the transition range ([4, 15] Mpc), the effects of neutrino masses overwhelm the effects of neutrino asymmetries, while in the two-halo-group range ([25, 50] Mpc), for both light and heavy haloes ([1013, 1015] M⊙), the effects of neutrino asymmetries dominate, making it possible to disentangle the two effects. We provide fitting formulae to quantify the effects of neutrino mass and asymmetry on halo–halo pairwise velocities.

Theoretical and Experimental Challenges in the Measurement of Neutrino Mass

Neutrino masses are yet unknown. We discuss the present state of effective electron antineutrino mass from β decay experiments; effective Majorana neutrino mass from neutrinoless double-beta decay experiments; neutrino mass squared differences from neutrino oscillation: solar, atmospheric, reactor, and accelerator-based experiments; sum of neutrino masses from cosmological observations. Current experimental challenges in the determination of neutrino masses are briefly discussed. The main focus is devoted to contemporary experiments.

Mitigating the optical depth degeneracy in the cosmological measurement of neutrino masses using 21-cm observations

Mitigating the optical depth degeneracy in the cosmological measurement of neutrino masses using 21-cm observations

Dark energy black holes with intermediate masses at high redshifts: An earlier generation of quasars and observations

Dark energy is the largest fraction of the energy density of our universe — yet it remains one of the enduring enigmas of our times. Here we show that dark energy can be used to solve 2 tantalizing mysteries of the observable universe. We build on existing models of dark energy linked to neutrino masses. In these models, dark energy can undergo phase transitions and form black holes. Here we look at the implications of the family structure of neutrinos for the phase transitions in dark energy and associated peaks in black hole formation. It has been previously shown that one of these peaks in black hole formation is associated with the observed peak in quasar formation at redshifts [Formula: see text]. Here, we predict that there will also be an earlier peak in the dark energy black holes at high redshifts [Formula: see text]. These dark energy black holes formed at high redshifts are Intermediate Mass Black Holes (IMBHs). These dark energy black holes at large redshift can help explain both the EDGES observations and the observations of large Supermassive Black Holes (SMBHs) at redshifts of 7 or larger. This work directs us to actively look for these dark energy black holes at these high redshifts as predicted here through targeted searches for these black holes at the redshifts [Formula: see text] near 18. There is a slight dependence of the location of the peak on the lightest neutrino mass. This may enable a measurement of the lightest neutrino mass — something which has eluded us so far. Finding these dark energy black holes of Intermediate Mass should be within the reach of upcoming observations — particularly with the James Webb Space Telescope — but perhaps also through the use of other innovative techniques focusing specifically on the redshifts [Formula: see text] around 18.

In Situ Tritium Decontamination of the KATRIN Rear Wall Using an Ultraviolet/Ozone Treatment

The KArlsruhe TRItium Neutrino (KATRIN) collaboration aims to determine the neutrino mass with a sensitivity of 0.2 eV/c2 (90% confidence level). This will be achieved by probing the end-point region of the β-electron spectrum of gaseous tritium with an electrostatic spectrometer. A gold-coated stainless steel disk defines the reference potential for high-precision neutrino mass measurement, and it terminates the β-electron flux as the physical boundary of the tritium source. This so-called rear wall is exposed to tritium, which leads to adsorption and absorption. This in turn leads to systematic uncertainties for the neutrino mass measurements that need to be understood and mitigated. In maintenance phases, during which the gaseous tritium source was emptied (<10−5 of nominal gas density), the activity that accumulated on the rear wall during normal operation was monitored using beta-induced X-ray spectrometry (BIXS) and direct observation of emitted β electrons with a silicon detector. Dependency of the observed activity increase on the integral tritium throughput was investigated and found to converge from limited exponential growth to continuous linear growth. This paper gives an overview of the results that were obtained using several methods of in situ decontamination of the rear wall while continuously monitoring the activity. The decontamination methods included heating during continuous evacuation; flushing the system with nitrogen, deuterium, or air with residual humidity at different pressures; and illumination of the rear wall with ultraviolet (UV) light. These well-known methods led to only a small ( ≈ 15%) decrease in the observed activity. However, a decrease of the surface activity by three orders of magnitude in less than 1 week was achieved by combination of different methods using UV light, a heated surface, and a low (5 to 100 mbar) pressure of air inside the chamber, leading to the production of highly reactive ozone. This proved to be by far the most efficient method, drastically reducing the contribution of the rear wall surface activity to the β spectrum of the gaseous source.

Toward neutrino mass from cosmology without optical depth information

With low-redshift probes reaching unprecedented precision, uncertainty of the cosmic microwave background (CMB) optical depth is expected to be the limiting factor for future cosmological neutrino mass constraints. In this paper, we discuss to what extent combinations of CMB lensing and galaxy survey measurements at low redshifts $z\ensuremath{\sim}0.5--5$ will be able to make competitive neutrino mass measurements without relying on any optical depth constraints. We find that the combination of LSST galaxies and CMB-S4 lensing should be able to achieve constraints on the neutrino mass sum of 25 meV without optical depth information, an independent measurement that is competitive with or slightly better than the constraint of 30 meV possible with CMB-S4 and present-day optical depth measurements. These constraints originate in both structure growth probed by cross-correlation tomography over a wide redshift range as well as, most importantly, the shape of the galaxy power spectrum measured over a large volume. We caution that possible complications such as higher-order biasing and systematic errors in the analysis of high-redshift galaxy clustering are only briefly discussed and may be non-negligible. Nevertheless, our results show that new kinds of high-precision neutrino mass measurements at and beyond the present-day optical depth limit may be possible.

Plutonium-241 as a possible isotope for neutrino mass measurement and capture

Tritium has been the isotope of choice for measurements of the absolute neutrino mass and planned detection of the relic neutrino background. The low mass of 3H leads to large recoil energy of the nucleus. This has emerged as a limiting factor in both measurements. We investigate 241Pu as an alternative. The recoil is 80 times smaller and it has similar decay energy and a lifetime to 3H. We evaluate for the first time its soft-neutrino capture cross-section and find (σ v) ν = 1.52 × 10−45 cm2. This is 40% of the capture cross-section for tritium, making 241Pu an interesting alternative for 3H.

SYNCA: A Synthetic Cyclotron Antenna for the Project 8 Collaboration

Cyclotron Radiation Emission Spectroscopy (CRES) is a technique for measuring the kinetic energy of charged particles through a precision measurement of the frequency of the cyclotron radiation generated by the particle's motion in a magnetic field. The Project 8 collaboration is developing a next-generation neutrino mass measurement experiment based on CRES. One approach is to use a phased antenna array, which surrounds a volume of tritium gas, to detect and measure the cyclotron radiation of the resulting β-decay electrons. To validate the feasibility of this method, Project 8 has designed a test stand to benchmark the performance of an antenna array at reconstructing signals that mimic those of genuine CRES events. To generate synthetic CRES events, a novel probe antenna has been developed, which emits radiation with characteristics similar to the cyclotron radiation produced by charged particles in magnetic fields. This paper outlines the design, construction, and characterization of this Synthetic Cyclotron Antenna (SYNCA). Furthermore, we perform a series of measurements that use the SYNCA to test the position reconstruction capabilities of the digital beamforming reconstruction technique. We find that the SYNCA produces radiation with characteristics closely matching those expected for cyclotron radiation and reproduces experimentally the phenomenology of digital beamforming simulations of true CRES signals.

Detector Array Readout with Traveling Wave Amplifiers

Reducing noise to the quantum limit over a large bandwidth is a fundamental requirement for future applications operating at millikelvin temperatures, such as the neutrino mass measurement, the next-generation X-ray observatory, the CMB measurement, the dark matter and axion detection, and the rapid high-fidelity readout of superconducting qubits. The read out sensitivity of arrays of microcalorimeter detectors, resonant axion-detectors, and qubits, is currently limited by the noise temperature and bandwidth of the cryogenic amplifiers. The Detector Array Readout with Traveling Wave Amplifiers project has the goal of developing high-performing innovative traveling wave parametric amplifiers with a high gain, a high saturation power, and a quantum-limited or nearly quantum-limited noise. The practical development follows two different promising approaches, one based on the Josephson junctions and the other one based on the kinetic inductance of a high-resistivity superconductor. In this contribution, we present the aims of the project, the adopted design solutions and preliminary results from simulations and measurements.

Neutrino Mass Measurements Using Cryogenic Detectors

The determination of the absolute mass scale of neutrinos is one of the most important challenges in Particle Physics. The shape of the endpoint region of beta ^--decay and electron capture (EC) spectra depends on the phase space factor, which, in turn, is function of the masses of the neutrino mass eigenstates. High energy resolution and high statistics measurements of beta ^- and EC spectra are therefore considered a model-independent way for the determination of the neutrino mass scale. Since almost four decades, low temperature microcalorimeters are used for the measurement of low energy beta ^- and EC spectra. The first efforts were focused on the development of large arrays for the measurement of the ^{187}Re beta ^--spectrum. In the last ten years, the attention moved to EC of ^{163}Ho. This choice was mainly motivated by the very good performance which could be achieved with low temperature microcalorimeters enclosing ^{163}Ho with respect to microcalorimeters with absorber containing ^{187}Re. The development of low temperature microcalorimeters for the measurement of the finite neutrino mass is discussed and, in particular, the reasons for moving from ^{187}Re to ^{163}Ho. The possibility to reach sub-eV sensitivity on the effective electron neutrino mass with ^{163}Ho, thanks to the multiplexing of large microcalorimeter arrays is demonstrated. In conclusion, an overview on other nuclides which have been proposed as good candidates, motivated by the excellent performance of low temperature microcalorimeters is presented.

Probing the Neutrino-Mass Scale with the KATRIN Experiment

The absolute mass scale of neutrinos is an intriguing open question in contemporary physics. The as-yet-unknown mass of the lightest and, at the same time, most abundant massive elementary particle species bears fundamental relevance to theoretical particle physics, astrophysics, and cosmology. The most model-independent experimental approach consists of precision measurements of the kinematics of weak decays, notably tritium β decay. With the KATRIN experiment, this direct neutrino-mass measurement has entered the sub-eV domain, recently pushing the upper limit on the electron-based neutrino mass down to 0.8 eV (90% CL) on the basis of first-year data out of ongoing, multiyear operations. Here, we review the experimental apparatus of KATRIN, the progress of data taking, and initial results. While KATRIN is heading toward the target sensitivity of 0.2 eV, other scientific goals are pursued. We discuss the search for light sterile neutrinos and an outlook on future keV-scale sterile-neutrino searches as well as further physics opportunities beyond the Standard Model.

Effective Majorana Neutrino Mass for ΔL = 2 Neutrino Oscillations

It is well known that the observations of neutrinoless double-beta decay prove the Majorana nature of the neutrino. However, with specific values of Majorana phases, the effective Majorana neutrino mass to be estimated from the observation of neutrinoless double-beta decay experiments is strongly suppressed if the neutrino mass pattern adheres to a normal ordering. In this case, double-beta decay might not be observed even though the neutrino is Majorana in nature. We show if neutrinos oscillate to antineutrinos in their propagation; then, the observation of this oscillation proves that neutrinos are Majorana and will provide a measurement of neutrino masses and Majorana phases.

Lensing power spectrum of the cosmic microwave background with deep polarization experiments

Precise reconstruction of the cosmic microwave background lensing potential can be achieved with deep polarization surveys by iteratively removing lensing-induced $B$ modes. We introduce a lensing spectrum estimator and its likelihood for such optimal iterative reconstruction. Our modeling shares similarities to the state-of-the-art likelihoods for quadratic estimator (QE)-based lensing reconstruction. In particular, we generalize the ${N}^{(0)}$ and ${N}^{(1)}$ lensing biases, and design a realization-dependent spectrum debiaser, making this estimator robust to uncertainties in the data modeling. We demonstrate unbiased recovery of the cosmology using map-based reconstructions, focussing on lensing-only cosmological constraints and neutrino mass measurement in combination with CMB spectra and acoustic oscillation data. We find this spectrum estimator is essentially optimal and with a diagonal covariance matrix. For a CMB-S4 survey, this likelihood can double the constraints on the lensing amplitude compared to the QE on a wide range of scales, while at the same time keeping numerical cost under control and being robust to errors.

High-precision electron-capture Q value measurement of 111In for electron-neutrino mass determination

A precise determination of the ground state 111In (9/2+) electron capture to ground state of 111Cd (1/2+) Q value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture Q value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for 111Cd was used to determine whether the four states are energetically allowed for a potential ultra-low Q-value β decay or electron-capture decay. Our results confirm that the excited states of 866.60(6) keV with spin-parity (Jπ) of 3/2+ and 864.8(3) keV with Jπ=3/2+ are ruled out due to their deduced electron-capture Q value being smaller than 0 keV at the level of around 20σ and 50σ, respectively. Electron-capture decays to the excited states at 853.94(7) keV (Jπ=7/2+) and 855.6(10) keV (Jπ=3/2+), are energetically allowed with Q values of 3.69(19) keV and 2.0(10) keV, respectively. The allowed decay transition 111In (9/2+) → 111Cd (7/2+), with a Q value of 3.69(19) keV, is a potential new candidate for neutrino-mass measurements by future EC experiments featuring new powerful detection technologies. The results show that the indium level 2p1/2 for this decay branch leads to a significant increase in the number of EC events in the energy region sensitive to the electron neutrino mass.

Cosmic neutrino background detection in large-neutrino-mass cosmologies

The cosmic neutrino background (CNB) is a definite prediction of the standard cosmological model and its direct discovery would represent a milestone in cosmology and neutrino physics. In this work, we consider the capture of relic neutrinos on a tritium target as a possible way to detect the CNB, as aimed for by the PTOLEMY project. Crucial parameters for this measurement are the absolute neutrino mass ${m}_{\ensuremath{\nu}}$ and the local neutrino number density ${n}_{\ensuremath{\nu}}^{\mathrm{loc}}$. Within the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model, cosmology provides a stringent upper limit on the sum of neutrino masses of $\ensuremath{\sum}{m}_{\ensuremath{\nu}}&lt;0.12\text{ }\text{ }\mathrm{eV}$, with further improvements expected soon from galaxy surveys by DESI and EUCLID. This makes the prospects for a CNB detection and a neutrino mass measurement in the laboratory very difficult. In this context, we consider a set of nonstandard cosmological models that allow for large neutrino masses (${m}_{\ensuremath{\nu}}\ensuremath{\sim}1\text{ }\text{ }\mathrm{eV}$), potentially in reach of the KATRIN neutrino mass experiment or upcoming neutrinoless double-beta decay searches. We show that the CNB detection prospects could be much higher in some of these models compared to those in $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$, and discuss the potential for such a detection to discriminate between cosmological scenarios. Moreover, we provide a simple rule to estimate the required values of energy resolution, exposure, and background rate for a PTOLEMY-like experiment to cover a certain region in the $({m}_{\ensuremath{\nu}},{n}_{\ensuremath{\nu}}^{\mathrm{loc}})$ parameter space. Alongside this paper, we publicly release a code to calculate the CNB sensitivity in a given cosmological model.