New Instruments for Neutrino Relics and Mass

Monday 8 Dec 2008, 08:45 → 18:00 Europe/Zurich

6-2-024 AB Auditorium (CERN)

We will bring together experts in both theory and experiment to evaluate the prospects for measuring the absolute neutrino mass with new (post-KATRIN) technologies, and for eventually detecting cosmological neutrino relics with radioactive isotopes. These technologies include radioactive ion storage rings, crystallized beams, beta beams, atomic spectroscopy, low-Q isotopes, laser atomic trapping, laser detection, and evaporative cooling. The goal of this workshop will be to identify promising directions for detector and beams technology development, stimulate theoretical work useful towards these measurements, identify the technologies which can reach the next orders of magnitude over KATRIN sensitivity and possibly discover neutrino relics, and to sketch a design for a next-generation neutrino mass instrument or research that could lead in this direction.

08:45 → 09:00 Welcome

08:45 Welcome

Welcome and suggest goals for the workshop

Speaker: Dr Bob McElrath (CERN)

Slides welcome.pdf

09:00 → 10:40 Experimental Techniques

09:00 Oscillations of Moessbauer neutrinos

We discuss the phenomenology of the Mössbauer neutrino experiment proposed recently by Raghavan. In particular, we will show that Mössbauer neutrinos do oscillate, in spite of their extremely small energy uncertainty. Using a quantum field theoretical approach, we will compute the combined rate of Mössbauer neutrino production, oscillation and detection, and discuss the arising coherence and localization conditions.

Speaker: Mr Joachim Kopp (Max Planck Institute for Nuclear Physics)

Slides kopp-moessbauer.pdf.pdf

09:25 One-dimensional ordering in high-energy ion beams

A sudden reduction of momentum spread, and under certain conditions also of Schottky-noise power, has been observed with electron-cooled beams at a few ion storage rings. This has been interpreted as an effect of one-dimensional ordering of the beams, such that the ions line up after one another in the ring. A brief overview of subject of beam crystallization or beam ordering is given, and results from observations and measurements of beam ordering at CRYRING in Stockholm are given together with a model of the ordered beam.

Speaker: Dr Håkan Danared (Manne Siegbahn Laboratory)

Slides NeutrinoRelicsAndMass.pdf NeutrinoRelicsAndMass.ppt

09:50 Contribution of Penning trap mass spectrometry to neutrino physics

Penning traps provide nowadays highest sensitivity, precision and accuracy for atomic mass spectrometry [1]. In the combined strong magnetic field and weak electric field of a Penning trap a charged particle can be stored and observed for long time thus frequency comparisons well below ppb can be performed. Different techniques such as non-destructive detection with single ion sensitivity or destructive time-of-flight resonance techniques are available to measure with high resolution the motional frequencies in the trap, yielding the free space cyclotron frequency which is inversely proportional to the charged particles mass. References 1. K. Blaum, Phys. Rep. 425, 1-78 (2006) 2. Sz. Nagy et al., Europhys. Lett. 74, 404?410 (2006) 3 G. Douysset et al., Phys. Rev. Lett. 86, 4259 - 4262 (2001) 4. M. Suhonen et al., JINST 2, P06003 (2007) 5. M. Redshaw et al., Phys. Rev. Lett. 98, 053003 (2007) A number of important mass measurements with remarkable precision have been performed for applications in neutrino physics experiments studying beta-decay or searching for neutrinoless double-beta-decay (0nBB) or radiative neutrinoless double electron capture (0n2EC) processes, where the atomic mass of the initial and final state nuclei or the mass difference are a much needed input. The mass measurement principle will be introduced and the different detection techniques will be compared. The latest advances shall be summarized, new ideas and upcoming experiments will be presented. The talk will cover some of the recent highlights such as the measurement of the 3H-3He mass difference giving the endpoint of the tritium beta-decay with 1.2 eV precision [2], the 76Ge-76Se Q-value of 2039.006(50) keV [3,4] and the 136Xe-136Ba Q-value 2457.83(37) [5].

Speaker: Dr Szilard Nagy (MPI-K)

Slides Nagy-CERN-08122008.pdf Nagy-CERN-08122008.pptx

10:15 Bounds on sterile neutrinos using full kinematic reconstruction of radioactive decays

Current bounds on mixing angles for light (several keV range) sterile neutrinos are rather weak, though theoretically it is a very interesting region. An interesting experimental technique for analysing such neutrinos is full kinematic reconstruction of the nuclear beta decay. This method, in principle, allows an event by event measurement of the neutrino mass, compared to large statistical noise of the kink search in the usual electron spectrum. I'll discuss advantages and problems of this approach.

Speaker: Mr Fedor Bezrukov (MPI fur Kernphysik)

Slides recoil.pdf

10:40 → 11:10 break

11:10 → 12:40 Existing Experiments

11:10 The MARE project: the calorimetric approach potential

The international project "Microcalorimeter Arrays for a Rhenium Experiment" (MARE) aims at a direct and calorimetric measurement of the electron antineutrino mass with sub-electronvolt sensitivity. The experimental strategy consists in analysing the beta spectrum of 187Re near the end-point looking for the spectral distortion expected for a finite antineutrino mass. In these experiments the detectors are thermal calorimeters with absorbers made of rhenium or of one of its compounds. Therefore the beta decay source is internal to the sensitive detector removing the most severe systematic uncertainties which have plagued the traditional and, so far, more sensitive spectrometers. In the final experimental phase, large arrays with as many as 10000 detectors each will be realized. At least five arrays will be then deployed to collect the statistics required to probe the antineutrino mass with a sensitivity of at least 0.2 eV, comparable to the one expected for the Katrin experiment. In this talk I would like to give an update on the status of the MARE experimental activity and their prospects. I will then discuss the results of a detailed study of the sensitivity achievable with the calorimetric approach.

Speaker: Angelo Nucciotti (INFN Milano-Bicocca / Dip. di Fisica U. di Milano-Bicocca)

Slides talk.pdf

11:40 Orbital electron capture decay of hydrogen-like ions (GSI)

At GSI Darmstadt, we have studied the decay of highly-charged heavy ions, stored and cooled in the experimental storage ring, ESR, by means of time-resolved Schottky-noise mass spectroscopy. The Fast Fourier Transform, FFT, of the Schottky noise is a non-destructive, non-instantaneous detection method, sensitive to a single heavy ion circulating in the ring. We have focused our interest on the two-body orbital electron capture decay of hydrogen-like ions, and have developed a method that allows us to identify unambiguously the decay channel and the decay time by observing both the parent and the daughter ions. We have investigated the decay of small numbers of particles stored and cooled in the ring, and we have observed deviations from the expected exponential decay of 140 Pr and 142 Pm ions [1]. In this contribution, I will concentrate on the motivation, on the method, and on the experimental findings of these studies.

Speaker: Dr Christophor Kozhuharov (GSI)

Slides KozhuharovCern20081208.pdf KozhuharovCern20081208.ppt

12:10 The Karlsruhe Tritium Neutrino Experiment KATRIN

The KArlsruher TRItium Neutrino experiment KATRIN is going to search for the neutrino mass from the endpoint region of the tritium beta decay spectrum with one order of magnitude higher sensitivity of 0.2 eV/c2 compared to previous direct neutrino mass experiments. This sensitvity will allow to distinguish between hierarchical and quasi-degenerate neutrino mass scenarios as well as to investigate the whole cosmological relevant neutrino mass range. The KATRIN experiment is currently being set up at Forschungszentrum Karlsruhe/Germany by an international collaboration. The key elements of KATRIN are a windowless gaseous molecular tritium source with an ultra-high luminosity and which minimizes systematic uncertainties, a very effective tritium retention and electron guiding system, the 23m long and 10m diameter main spectrometer of MAC-E-Filter type, and an electron detector. This setup allows to measure the tritium beta spectrum with unprecedented signal rate and energy resolution of 0.93eV. The scientific context, the present status of KATRIN, its technical challenges and a discussion on KATRIN`s systematics and sensitivity will be presented.

Speaker: Prof. Christian Weinheimer (University of Münster, Germany)

Slides cern_weinheimer.pdf

12:40 → 14:00 lunch

14:00 → 15:15 Theory and Cosmology

14:00 The electron endpoint from accelerated ions - a new route to the neutrino mass scale?

We introduce the possibility of determining the neutrino mass scale from monitoring the decays of a crystalised beam. Through the careful control of the beam momentum, one can perform a 'cut' on the electron spectrum with only electrons near the endpoint traveling backwards in the laboratory frame. The idea is introduced with the results from preliminary simulations presented.

Speaker: Christopher Orme (Durham University)

Slides orme_endpt.pdf

14:25 Measuring the neutrino mass from large scale structure

Future large scale structure surveys provide one of the most promising techniques for probing the neutrino mass. I will present results from detailed N-body simulations of structure formation in models with neutrino mass. Such simulations are necessary for the next generation of surveys such as the LSST

Speaker: Prof. Steen Hannestad (University of Aarhus)

Slides hannestad_cern2008.pdf hannestad_cern2008.ppt

14:50 The GSI anomaly and neutrino mixing

It will be shown why the GSI anomaly can in principle not be due to neutrino mixing.

Speaker: Prof. Manfred Lindner (Max Planck Institut fuer Kernphysik)

Slides lindner.pdf

15:15 → 15:45 break

15:45 → 17:30 Relic Detection

15:45 Coherent target effects for atomic neutrino mass spectroscopy and detection of relic neutrino

New experimental method using isolated atoms and molecules implanted in sold matrix is explained, whose goal is to measure all 3 neutrino masses and the unknown mixing angle along with determination of Majorana or Dirac particle. If the method works, it is expected to detect the cosmic relic neutrino, too.

Speaker: Motohiko Yoshimura (Okayama University)

16:15 Emergent Electroweak Gravity

We show that the cosmic neutrino background is a superfluid today, and the quantum numbers of the order parameter give a goldstone graviton, with a coupling numerically similar to the actual Newton's constant.

Speaker: Dr Bob McElrath (CERN)

Slides ewgravity_newinst.pdf

16:40 Relic neutrino detection using beta decaying nuclei

We present a study on the interaction of low energy electron neutrinos on nuclei that undergo both beta decay and electron capture. We show that, due to the absence of an energy threshold and to the relatively high value of the cross section, these processes are the only ones to date having a realistic chance to unambiguously detect the yet undiscovered cosmological relic neutrino background.

Speaker: Dr Alfredo Giuseppe Cocco (Istituto Nazionale di Fisica Nucleare)

Slides CERN_cocco.pdf

17:05 Experimental challenges towards the detection of relic neutrinos with unstable nuclei

In this talk I will review the experimental challenges towards the detection of relic neutrinos. The talk is based on a paper where the idea of detecting relic neutrinos with instable nucli is renewed. Different target nucli and experimental approaches are considered and, the advantage and the difficulties of different experimental techniques are discussed.

Speaker: Dr Marcello Messina (University of Bern)

Slides CERNworkshop.pdf

17:30 → 18:00 Discussion/Plans for Future