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8 results on '"nucleus: transition"'

1. Searching for the $\beta^+$EC and EC/EC Decays of $^{74}$Se

Author

E. Rukhadze, V.I. Umatov, V. B. Brudanin, Yu. Shitov, S. I. Konovalov, I. Stekl, N. I. Rukhadze, A. S. Barabash, G. Warot, A. V. Rakhimov, A. A. Klimenko, Laboratoire Souterrain de Modane (LSM - UMR 6417), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Hadron, Analytical chemistry, General Physics and Astronomy, lifetime: measured, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Water equivalent, 7. Clean energy, 01 natural sciences, energy: transition, background: low, double-beta decay: (0neutrino), Double beta decay, 0103 physical sciences, double-beta decay: (2neutrino), 010302 applied physics, Physics, 010308 nuclear & particles physics, selenium: lifetime, neutrino: Majorana: mass, neutrino: exchange, selenium: semileptonic decay, nucleus: transition, Excited state, Underground laboratory, Hpge detector, selenium: nuclide, experimental results
Abstract

International audience; Double beta decay (β$^{+}$EC, EC/EC) of $^{74}$Se was investigated at the Modane underground laboratory (LSM, France; 4800 m of water equivalent) using the OBELIX ultralow-background HPGe detector with a sensitive volume of 600 cm$^{3}$ and a sample of natural selenium with a mass of 1.6 kg containing ~0.89% (~14.24 g) of $^{74}$Se. The new experimental limits for β$^{+}$EC and EC/EC decays of $^{74}$Se to ground 0$^{+}$ and excited $2_{1}^{ + },$ 596 keV, and $2_{2}^{ + },$ 1204 keV states of $^{74}$Ge, were obtained from experimental data accumulated over 135 days.

Published
2020
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2. Anomalies in $^8$Be nuclear transitions and $(g-2)_{e,\mu}$: towards a minimal combined explanation

Author

A. M. Teixeira, J. Kriewald, Jon Orloff, Chandan Hati, Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Physics beyond the Standard Model, Scalar (mathematics), Parameter space, 01 natural sciences, electron: pair production, Theoretical physics, dipole: magnetic, Z', Gauge group, 0103 physical sciences, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Neutrino Physics, 010306 general physics, numerical calculations, lepton: mass, Boson, Physics, 010308 nuclear & particles physics, new physics, lepton: mixing, Fermion, symmetry: U(1), lepton: magnetic moment, beryllium, ddc, High Energy Physics - Phenomenology, nucleus: transition, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Beyond Standard Model, lcsh:QC770-798, fermion: vector particle, B-L number, Magnetic dipole, Lepton
Abstract

Motivated by a simultaneous explanation of the apparent discrepancies in the light charged lepton anomalous magnetic dipole moments, and the anomalous internal pair creation in $^8$Be nuclear transitions, we explore a simple New Physics model, based on an extension of the Standard Model gauge group by a $U(1)_{B-L}$. The model further includes heavy vector-like fermion fields, as well as an extra scalar responsible for the low-scale breaking of $U(1)_{B-L}$, which gives rise to a light $Z^\prime$ boson. The new fields and currents allow to explain the anomalous internal pair creation in $^8$Be while being consistent with various experimental constraints. Interestingly, we find that the contributions of the $Z^\prime$ and the new $U(1)_{B-L}$-breaking scalar can also successfully account for both $(g-2)_{e,\mu}$ anomalies; the strong phenomenological constraints on the model's parameter space ultimately render the combined explanation of $(g-2)_e$ and the anomalous internal pair creation in $^8$Be particularly predictive. The underlying idea of this minimal "prototype model" can be readily incorporated into other protophobic $U(1)$ extensions of the Standard Model., Comment: 32 pages, 6 figures

Published
2020
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3. Investigation of $\beta^+$EC, EC/EC processes in $^{74}$Se

Author

G. Warot, A. V. Rakhimov, V. B. Brudanin, I. Stekl, N. I. Rukhadze, V. I. Umatov, E. Rukhadze, S. I. Konovalov, Yu. A. Shitov, A. A. Klimenko, A. S. Barabash, Laboratoire Souterrain de Modane (LSM - UMR 6417), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Materials science, 010308 nuclear & particles physics, Radiochemistry, selenium: lifetime, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, energy: transition, neutrino: exchange, background: low, nucleus: transition, selenium: semileptonic decay, Volume (thermodynamics), chemistry, double-beta decay: (0neutrino), Double beta decay, 0103 physical sciences, Underground laboratory, double-beta decay: (2neutrino), 010306 general physics, Hpge detector, selenium: nuclide, Selenium, experimental results
Abstract

International audience; Investigation of double beta decay processes (β+EC, EC/EC) of 74Se was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using ultra low-background HPGe detector Obelix with sensitive volume of 600 cm3 and a sample of natural selenium with a mass of 1.6 kg, containing ∼0.89% (∼14.24 g) of 74Se. New experimental limits (at 90 % CL) on double beta decay transitions of 74Se to the ground and exited states of 74Ge were obtained from the preliminary calculation of experimental data accumulated in 135 days.

Published
2019
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4. Detailed studies of $^{100}$Mo two-neutrino double beta decay in NEMO-3

Author

S. Blot, I. Vanushin, Lukas Fajt, M. Bongrand, Frédéric Nowacki, Karel Smolek, R. Saakyan, C. Vilela, B. Soulé, C. Augier, Masaharu Nomachi, Vl. I. Tretyak, S. Jullian, A. Smetana, V.E. Kovalenko, H. Gómez, Y. A. Ramachers, Jose Busto, F. Mauger, J. J. Evans, P. Guzowski, Y. Lemière, A. S. Barabash, S. Calvez, C. Patrick, A. Huber, D.V. Filosofov, M. Macko, Jouni Suhonen, A. Chapon, X. Sarazin, F. Xie, A. Chopra, Z. J. Liptak, A. J. Caffrey, R. Hodák, A. Žukauskas, V.I. Umatov, J.P. Cesar, Ph. Hubert, S. Torre, C. Girard-Carillo, X. Garrido, V. G. Egorov, O.I. Kochetov, S. Söldner-Rembold, F. Mamedov, E. Rukhadze, Yu. Shitov, V. Brudanin, D. Boursette, G. Eurin, D. Waters, J. C. Thomas, J. K. Sedgbeer, S. I. Konovalov, H. Ohsumi, F. Piquemal, T. Le Noblet, E. Chauveau, Guillaume Lutter, Dominique Durand, R. Dvornický, C. Cerna, Kevin Lang, Pavel P. Povinec, Ch. Marquet, C. Macolino, G. Oliviéro, C. Hugon, F. Nova, A. Minotti, A. Pin, R. L. Flack, L. Dawson, D. Lalanne, J. L. Reyss, B. Morgan, Michele Cascella, P. Loaiza, C. L. Riddle, R. B. Pahlka, L. Simard, D. Duchesneau, A. Remoto, R. Salazar, X.R. Liu, C.S. Sutton, R. Arnold, V. I. Tretyak, A.A. Smolnikov, G. Szklarz, B. Guillon, Fedor Šimkovic, P. Přidal, Igor Nemchenok, J. Mott, V. V. Timkin, Vit Vorobel, A. Salamatin, A. Basharina-Freshville, F. Perrot, H. Tedjditi, S. Blondel, I. Stekl, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Souterrain de Modane (LSM - UMR 6417), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), NEMO-3, Arnold, R, Augier, C, Barabash, A, Basharina-Freshville, A, Blondel, S, Blot, S, Bongrand, M, Boursette, D, Brudanin, V, Busto, J, Caffrey, A, Calvez, S, Cascella, M, Cerna, C, Cesar, J, Chapon, A, Chauveau, E, Chopra, A, Dawson, L, Duchesneau, D, Durand, D, Dvornicky, R, Egorov, V, Eurin, G, Evans, J, Fajt, L, Filosofov, D, Flack, R, Garrido, X, Girard-Carillo, C, Gomez, H, Guillon, B, Guzowski, P, Hodak, R, Huber, A, Hubert, P, Hugon, C, Jullian, S, Kochetov, O, Konovalov, S, Kovalenko, V, Lalanne, D, Lang, K, Lemiere, Y, Noblet, T, Liptak, Z, Liu, X, Loaiza, P, Lutter, G, Macko, M, Macolino, C, Mamedov, F, Marquet, C, Mauger, F, Minotti, A, Morgan, B, Mott, J, Nemchenok, I, Nomachi, M, Nova, F, Nowacki, F, Ohsumi, H, Oliviero, G, Pahlka, R, Patrick, C, Perrot, F, Pin, A, Piquemal, F, Povinec, P, Pridal, P, Ramachers, Y, Remoto, A, Reyss, J, Riddle, C, Rukhadze, E, Saakyan, R, Salamatin, A, Salazar, R, Sarazin, X, Sedgbeer, J, Shitov, Y, Simard, L, Simkovic, F, Smetana, A, Smolek, K, Smolnikov, A, Soldner-Rembold, S, Soule, B, Stekl, I, Suhonen, J, Sutton, C, Szklarz, G, Tedjditi, H, Thomas, J, Timkin, V, Torre, S, Tretyak, V, Umatov, V, Vanushin, I, Vilela, C, Vorobel, V, Waters, D, Xie, F, Zukauskas, A, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire d'Annecy de Physique des Particules (LAPP), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Science and Technology Facilities Council (STFC)

Subjects
Particle physics, S029MT, Physics and Astronomy (miscellaneous), FOS: Physical sciences, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, invariance: Lorentz, 01 natural sciences, 7. Clean energy, neutrinoless double beta decay, decay modes, Physics, Particles & Fields, double-beta decay: (0neutrino), SEARCH, Double beta decay, 0103 physical sciences, ground state, Nuclear Experiment (nucl-ex), 010306 general physics, 0206 Quantum Physics, Engineering (miscellaneous), Nuclear Experiment, Majoron, S076H2N, Physics, Science & Technology, HALF-LIFE, 010308 nuclear & particles physics, MO-100, High Energy Physics::Phenomenology, Nuclear & Particles Physics, violation: Lorentz, nucleus: transition, STATES, statistics, Physical Sciences, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, spectral, electron: energy spectrum, High Energy Physics::Experiment, Neutrino, Ground state, Energy (signal processing), Radioactive decay, Lepton
Abstract

The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $^{100}$Mo to the ground state of $^{100}$Ru, $T_{1/2} = \left[ 6.81 \pm 0.01\,\left(\mbox{stat}\right) ^{+0.38}_{-0.40}\,\left(\mbox{syst}\right) \right] \times10^{18}$ y. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $5\times10^5$ events and a signal-to-background ratio of ~80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of n=2,3,7, as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained., 11 pages, 9 figures

Published
2019
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5. Investigating the Double Beta Decay of $^{58}$Ni

Author

A. A. Klimenko, V. B. Brudanin, F. Piquemal, I. Stekl, E. Rukhadze, N. I. Rukhadze, Yu. Shitov, G. Warot, Laboratoire Souterrain de Modane (LSM - UMR 6417), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], energy: ground state, Hadron, Analytical chemistry, energy spectrum, General Physics and Astronomy, Water equivalent, 7. Clean energy, 01 natural sciences, Preliminary analysis, energy: transition, nickel, double-beta decay: (0neutrino), Double beta decay, 0103 physical sciences, double-beta decay: (2neutrino), 010306 general physics, Physics, 010308 nuclear & particles physics, excited state: energy, semileptonic decay, 3. Good health, nucleus: transition, Excited state, Underground laboratory, Ground state, Hpge detector
Abstract

Double beta decay (β + EC, EC/EC) of 58Ni is investigated at France’s Modane Underground Laboratory (4800 m water equivalent) using the OBELIX ultralow-background HPGe detector with a sensitive volume of 600 cm3 and a natural nickel sample of ~68% 58Ni with a mass of ~21.7 kg. After preliminary analysis of the experimental data accumulated over ~144 days, new experimental limits are obtained for the 2νβ+EC decay of 58Ni to the 0+ ground state and the 2 1 + , 811 keV excited state of 58Fe, and for the 2νEC/EC decay of 58Ni to the 2 1 + , 811 keV and 2 2 + , 1675 keV excited states of 58Fe. The limits are T1/2(β+EC,0→0+) > 1.7 × 1022 yr, T1/2(β+EC,0→2 1 + ) > 2.3 × 1022 yr, T1/2(EC/EC,0→2 1 + ) > 3.3 × 1022 yr, and T1/2(EC/EC,0→2 2 + ) > 3.4 × 1022 yr. Experimental limit T1/2(0νEC/EC–res, 1918 keV > 4.1 × 1022 yr is obtained for resonant neutrinoless radiative EC/EC decay with an energy of 1918.3 keV. All limits are at 90% CL.

Published
2018
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6. Investigation of 2$\beta$ decay of $^{116}$Cd with the help of enriched $^{116}$CdWO$_4$ crystal scintillators

Author

V.V. Kobychev, R. Cerulli, M. Laubenstein, A. Incicchitti, S. I. Konovalov, V.M. Mokina, A. S. Barabash, D. V. Poda, F.A. Danevich, V. Caracciolo, V.N. Shlegel, F. Cappella, S. d'Angelo, P. Belli, D.V. Kasperovych, V. I. Tretyak, O. G. Polischuk, D. M. Chernyak, Ya.V. Vasiliev, R. Bernabei, V. I. Umatov, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière ( CSNSM ), and Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
energy: ground state, energy spectrum, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Crystal, double-beta decay: (0neutrino), Double beta decay, 0103 physical sciences, double-beta decay: (2neutrino), 116Cd, ground state, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, Nuclear Experiment, Majoron, Physics, 010308 nuclear & particles physics, nucleus, neutrino: Majorana: mass, double-beta decay, semileptonic decay, Beta decay, Automatic Keywords, MAJORANA, nucleus: transition, Excited state, scintillation counter: crystal, Neutrino, Atomic physics, Ground state
Abstract

Double beta decay of $^{116}$Cd has been investigated with the help of radiopure enriched $^{116}$CdWO$_4$ crystal scintillators in the experiment Aurora. The half-life of $^{116}$Cd relatively to the 2$\nu$2$\beta$ decay of $^{116}$Cd to the ground level of $^{116}$Sn is measured with the highest up-to-date accuracy as $T_{1/2}$ = [2.69 $\pm$ 0.02 (stat.) $\pm$ 0.14 (syst.)] $\times$ 10$^{19}$ yr. A new improved limit on the 0$\nu$2$\beta$ decay of $^{116}$Cd to the ground state of $^{116}$Sn is set as $T_{1/2}\geq 2.4 \times 10^{23}$ yr at 90\% C.L., that corresponds to the effective Majorana neutrino mass limit in the range $\langle$$m_\nu$$\rangle$ $\le$ $(1.1-1.6)$ eV, depending on the nuclear matrix elements used in the estimations. New improved limits on other $2\beta$ processes in $^{116}$Cd (decays with majoron emission, transitions to excited levels of $^{116}$Sn) were set at the level of $T_{1/2}\geq 10^{21}-10^{22}$ yr., Comment: 4 pages, 2 figures

Published
2017
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7. Investigation of double beta decay of $^{58}$Ni with the Obelix spectrometer

Author

F. Piquemal, N. I. Rukhadze, G. Warot, E. Rukhadze, A. A. Klimenko, Yu. Shitov, V. B. Brudanin, I. Stekl, Laboratoire Souterrain de Modane (LSM - UMR 6417), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
energy: ground state, Analytical chemistry, energy spectrum, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, energy: transition, nickel, double-beta decay: (0neutrino), Double beta decay, 0103 physical sciences, double-beta decay: (2neutrino), 010306 general physics, Physics, Spectrometer, 010308 nuclear & particles physics, excited state: energy, semileptonic decay, Nickel, nucleus: transition, chemistry, Excited state, Underground laboratory, spectrometer, Hpge detector
Abstract

International audience; Investigation of double beta decay processes (β+EC, EC/EC) of 58Ni was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using ultra low-background HPGe detector Obelix with sensitive volume of 600 cm3 and a sample of natural nickel, containing ∼68% of 58Ni with a mass of ∼21.7 kg. New experimental limits on 2νβ+EC decay of 58Ni to the ground 0+ and 21+, 811 keV excited state of 58Fe, and 2νEC/EC decay of 58Ni to 21+, 811 keV and 22+ 1 675 keV excited states of 58Fe were obtained from the preliminary calculation of experimental data accumulated in ∼88d. They are - T1/2(β+ EC, 0+ → 0+) > 1.4 ×1021 y; T1/2(β+EC,0+→21+)>1.7×1022 y, T1/2(EC/EC, 0+→21+)>2.4×1022 y, T1/2(EC/EC, 0+→22+)>2.1×1022 y. For resonant neutrino-less radiative EC/EC decay with energy of 1 918.3 keV a new experimental limit of T1/2 (0νEC/EC − res, 1918keV) > 4.7 ×1022 y was also obtained. All limits are at 90 % CL.

Published
2017
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8. Possible explanation of the electron positron anomaly at 17 MeV in 8 Be transitions through a light pseudoscalar

Author

Stefano Moretti, Ulrich Ellwanger, Laboratoire de Physique Théorique d'Orsay [Orsay] (LPT), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique d'Orsay [Orsay] ( LPT ), and Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Quark, Particle physics, Nuclear and High Energy Physics, Physics beyond the Standard Model, High Energy Physics::Lattice, FOS: Physical sciences, 01 natural sciences, law.invention, Nuclear physics, electron: pair production, High Energy Physics - Phenomenology (hep-ph), law, electron: coupling, 0103 physical sciences, pseudoscalar particle: coupling, Beam dump, 010306 general physics, Phenomenological Models, Coupling, Physics, 010308 nuclear & particles physics, new physics, High Energy Physics::Phenomenology, Yukawa potential, beryllium, pseudoscalar particle: mass, Pseudoscalar, High Energy Physics - Phenomenology, nucleus: transition, Supersymmetry Phenomenology, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Higgs boson, [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Anomaly (physics), coupling: Yukawa, new particle
Abstract

We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the $^8Be$ anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading to a short enough A life time consistent with an explanation of the anomaly., Comment: 12 pages, discussion of nuclear shell model corrected, to appear in JHEP

Published
2016
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