130 research outputs found

    A compact and robust diode laser system for atom interferometry on a sounding rocket

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    We present a diode laser system optimized for laser cooling and atom interferometry with ultra-cold rubidium atoms aboard sounding rockets as an important milestone towards space-borne quantum sensors. Design, assembly and qualification of the system, combing micro-integrated distributed feedback (DFB) diode laser modules and free space optical bench technology is presented in the context of the MAIUS (Matter-wave Interferometry in Microgravity) mission. This laser system, with a volume of 21 liters and total mass of 27 kg, passed all qualification tests for operation on sounding rockets and is currently used in the integrated MAIUS flight system producing Bose-Einstein condensates and performing atom interferometry based on Bragg diffraction. The MAIUS payload is being prepared for launch in fall 2016. We further report on a reference laser system, comprising a rubidium stabilized DFB laser, which was operated successfully on the TEXUS 51 mission in April 2015. The system demonstrated a high level of technological maturity by remaining frequency stabilized throughout the mission including the rocket's boost phase

    MNS Parameters from Neutrino Oscillations, Single Beta Decay and Double Beta Decay

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    We examine the constraints on the MNS lepton mixing matrix =66rom the present and future experimental data of the neutrino oscillation, tritium beta decay, and neutrinoless double beta decay for Majorana neutrinos. We show that the small mixing angle solutions for solar neutrino problem are disfavored for small averaged mass () of neutrinoless double beta decay ($\leq 0.01$ eV) in the inverse neutrino mass hierarchy scenario. This is the case even in the normal mass hierarchy scenario except for very restrictive value of the averaged neutrino mass ($\bar{m_\nu}$) of single beta decay. The lower mass bound for $\bar{m_\nu}$ is given from the present neutrino oscillation data. We obtain some relations between and mΜˉ\bar{m_\nu}. The constraints on the Majorana CP violating phases are also given.Comment: 25pages, 10figure

    A Large Scale Double Beta and Dark Matter Experiment: GENIUS

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    The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the Standard Model. To increase by a major step the present sensitivity for double beta decay and dark matter search much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We present here a study of a project proposed recently, which would operate one ton of 'naked' enriched GErmanium-detectors in liquid NItrogen as shielding in an Underground Setup (GENIUS). It improves the sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe neutrino masses even down to 10^-3 eV. The first version would allow to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow in addition significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking supersymmetry models, leptoquark masses and mechanism and right-handed W-boson masses comparable to LHC. The second issue of the experiment is the search for dark matter in the universe. The entire MSSM parameter space for prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment - with the same purity requirements but using only 100 kg of 76Ge or even of natural Ge - making the experiment competitive to LHC in the search for supersymmetry. The layout of the proposed experiment is discussed and the shielding and purity requirements are studied using GEANT Monte Carlo simulations. As a demonstration of the feasibility of the experiment first results of operating a 'naked' Ge detector in liquid nitrogen are presented.Comment: 22 pages, 12 figures, see also http://pluto.mpi-hd.mpg.de/~betalit/genius.htm

    Interferometry with Bose-Einstein Condensates in Microgravity

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    Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Due to their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this paper we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far-field of a double-slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.Comment: 8 pages, 3 figures; 8 pages of supporting materia

    Reheating-temperature independence of cosmological baryon asymmetry in Affleck-Dine leptogenesis

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    In this paper we point out that the cosmological baryon asymmetry in our universe is generated almost independently of the reheating temperature TRT_R in Affleck-Dine leptogenesis and it is determined mainly by the mass of the lightest neutrino, mÎœ1m_{\nu_1}, in a wide range of the reheating temperature TR≃105T_R\simeq 10^5--101210^{12} GeV. The present baryon asymmetry predicts the mÎœ1m_{\nu_1} in a narrow region, mÎœ1≃(0.3m_{\nu_1}\simeq (0.3--1)×10−91)\times 10^{-9} eV. Such a small mass of the lightest neutrino leads to a high predictability on the mass parameter mÎœeÎœem_{\nu_e \nu_e} contributing to the neutrinoless double beta decay. We also propose an explicit model in which such an ultralight neutrino can be naturally obtained.Comment: 22 pages, LaTeX, 9 eps figure

    Charge collection and electrode structures in ionization and phonon based dark matter detectors

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    We report on progress in our understanding of the physics of of implanted contacts, amorphous layer structures and Schottky contacts on detectors based on the simultaneous ionization and phonon based at 20 mK. Loss of charge for events near the contacts limits the capabilities of these detectors for detecting dark matter, an effect which is minimized by use of amorphous blocking layers

    Generalized Bounds on Majoron-neutrino couplings

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    We discuss limits on neutrino-Majoron couplings both from laboratory experiments as well as from astrophysics. They apply to the simplest class of Majoron models which covers a variety of possibilities where neutrinos acquire mass either via a seesaw-type scheme or via radiative corrections. By adopting a general framework including CP phases we generalize bounds obtained previously. The combination of complementary bounds enables us to obtain a highly non-trivial exclusion region in the parameter space. We find that the future double beta project GENIUS, together with constraints based on supernova energy release arguments, could restrict neutrino-Majoron couplings down to the 10^{-7} level.Comment: 17 pages, LateX, 7 figures, version to be published in Phys. Rev.

    Charge collection and electrode structures in ionization and phonon based dark matter detectors

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    We report on progress in our understanding of the physics of of implanted contacts, amorphous layer structures and Schottky contacts on detectors based on the simultaneous ionization and phonon based at 20 mK. Loss of charge for events near the contacts limits the capabilities of these detectors for detecting dark matter, an effect which is minimized by use of amorphous blocking layers

    Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions

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    Fundamental mechanisms for Majoron emitting neutrinoless double beta decay in SU(3)_C x G_W x U(1) models, for electroweak flavor chiral extensions, G_W = SU(3)_L and SU(4)_L are pointed out. Both kinds of known Majoron emitting processes, charged Majoron emitting where the massless Nambu-Goldstone boson itself carries lepton charge, L=−2L=-2, and the ordinary Majoron emitting where the boson has a small mass are found possible. PACS numbers: 11.15.Ex, 12.60.Fr, 14.80.CpComment: 18 pages, Revtex, 3 Postscript figures. To be published in Phys.Rev.D(1 May 1998
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