Explore the vast range of titles available.

We report on a search for ultralow-mass axionlike dark matter by analyzing the ratio of the spin-precession frequencies of stored ultracold neutrons and Hg199 atoms for an axion-induced oscillating electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range 10−24≤ma≤10−17eV . Our null result sets the first laboratory constraints on the coupling of axion dark matter to gluons, which improve on astrophysical limits by up to 3 orders of magnitude, and also improves on previous laboratory constraints on the axion coupling to nucleons by up to a factor of 40.

The NEMO-3 results for the double- β decay of 150 Nd to the 0 1 + and 2 1 + excited states of 150 Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope 150 Nd are used in the analysis. The signal of the 2 ν β β transition to the 0 1 + excited state is detected with a statistical significance exceeding 5 σ . The half-life is measured to be T 1 / 2 2 ν β β ( 0 1 + ) = 1 . 11 - 0.14 + 0.19 stat - 0.15 + 0.17 syst × 10 20  year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the 2 ν β β decay to the 2 1 + level the limit is T 1 / 2 2 ν β β ( 2 1 + ) > 2.42 × 10 20 year . The limits on the 0 ν β β decay to the 0 1 + and 2 1 + levels of 150 Sm are significantly improved to T 1 / 2 0 ν β β ( 0 1 + ) > 1.36 × 10 22 year and T 1 / 2 0 ν β β ( 2 1 + ) > 1.26 × 10 22 year .

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( \\text{ stat }\\right) ^{+0.38}_{-0.40}\\,\\left( \\text{ syst }\\right) \\right] \\times 10^{18}\\] year. 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\\times 10^5\\] events and a signal-to-background ratio of \\[\\sim \\] 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 \\[\\mathrm{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.

The NEMO-3 results for the double-$\\beta $ decay of $^{150}$Nd to the 0$^+_1$ and 2$^+_1$ excited states of $^{150}$Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope $^{150}$Nd are used in the analysis. The signal of the $2\\nu \\beta \\beta $ transition to the 0$^+_1$ excited state is detected with a statistical significance exceeding 5$\\sigma $. The half-life is measured to be $T_{1/2}^{2\\nu \\beta \\beta }(0^+_1) = \\left[ 1.11 ^{+0.19}_{-0.14} \\,\\left( \\hbox {stat}\\right) ^{+0.17}_{-0.15}\\,\\left( \\hbox {syst}\\right) \\right] \\times 10^{20}$ year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the $2\\nu \\beta \\beta $ decay to the 2$^+_1$ level the limit is $T^{2\\nu \\beta \\beta }_{1/2}(2^+_1) > 2.42 \\times 10^{20}~\\hbox {year}$. The limits on the $0\\nu \\beta \\beta $ decay to the 0$^+_1$ and 2$^+_1$ levels of $^{150}$Sm are significantly improved to $T_{1/2}^{0\\nu \\beta \\beta }(0^+_1) > 1.36 \\times 10^{22}~\\hbox {year}$ and $T_{1/2}^{0\\nu \\beta \\beta }(2^+_1) > 1.26 \\times 10^{22}~\\hbox {year}$.

The NEMO-3 results for the double-$$\\beta $$β decay of$$^{150}$$150 Nd to the 0$$^+_1$$1 + and 2$$^+_1$$1 + excited states of$$^{150}$$150 Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope$$^{150}$$150 Nd are used in the analysis. The signal of the$$2\\nu \\beta \\beta $$2 ν β β transition to the 0$$^+_1$$1 + excited state is detected with a statistical significance exceeding 5$$\\sigma $$σ . The half-life is measured to be$$T_{1/2}^{2\\nu \\beta \\beta }(0^+_1) = \\left[ 1.11 ^{+0.19}_{-0.14} \\,\\left( \\hbox {stat}\\right) ^{+0.17}_{-0.15}\\,\\left( \\hbox {syst}\\right) \\right] \\times 10^{20}$$T 1 / 2 2 ν β β ( 0 1 + ) = 1 . 11 - 0.14 + 0.19 stat - 0.15 + 0.17 syst × 10 20  year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the$$2\\nu \\beta \\beta $$2 ν β β decay to the 2$$^+_1$$1 + level the limit is$$T^{2\\nu \\beta \\beta }_{1/2}(2^+_1) > 2.42 \\times 10^{20}~\\hbox {year}$$T 1 / 2 2 ν β β ( 2 1 + ) > 2.42 × 10 20 year . The limits on the$$0\\nu \\beta \\beta $$0 ν β β decay to the 0$$^+_1$$1 + and 2$$^+_1$$1 + levels of$$^{150}$$150 Sm are significantly improved to$$T_{1/2}^{0\\nu \\beta \\beta }(0^+_1) > 1.36 \\times 10^{22}~\\hbox {year}$$T 1 / 2 0 ν β β ( 0 1 + ) > 1.36 × 10 22 year and$$T_{1/2}^{0\\nu \\beta \\beta }(2^+_1) > 1.26 \\times 10^{22}~\\hbox {year}$$T 1 / 2 0 ν β β ( 2 1 + ) > 1.26 × 10 22 year .

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

Abstract The NEMO-3 results for the double- $$\\beta $$ β decay of $$^{150}$$ 150 Nd to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + excited states of $$^{150}$$ 150 Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope $$^{150}$$ 150 Nd are used in the analysis. The signal of the $$2\\nu \\beta \\beta $$ 2 ν β β transition to the 0 $$^+_1$$ 1 + excited state is detected with a statistical significance exceeding 5 $$\\sigma $$ σ . The half-life is measured to be $$T_{1/2}^{2\\nu \\beta \\beta }(0^+_1) = \\left[ 1.11 ^{+0.19}_{-0.14} \\,\\left( \\hbox {stat}\\right) ^{+0.17}_{-0.15}\\,\\left( \\hbox {syst}\\right) \\right] \\times 10^{20}$$ T 1 / 2 2 ν β β ( 0 1 + ) = 1 . 11 - 0.14 + 0.19 stat - 0.15 + 0.17 syst × 10 20  year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the $$2\\nu \\beta \\beta $$ 2 ν β β decay to the 2 $$^+_1$$ 1 + level the limit is $$T^{2\\nu \\beta \\beta }_{1/2}(2^+_1) > 2.42 \\times 10^{20}~\\hbox {year}$$ T 1 / 2 2 ν β β ( 2 1 + ) > 2.42 × 10 20 year . The limits on the $$0\\nu \\beta \\beta $$ 0 ν β β decay to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + levels of $$^{150}$$ 150 Sm are significantly improved to $$T_{1/2}^{0\\nu \\beta \\beta }(0^+_1) > 1.36 \\times 10^{22}~\\hbox {year}$$ T 1 / 2 0 ν β β ( 0 1 + ) > 1.36 × 10 22 year and $$T_{1/2}^{0\\nu \\beta \\beta }(2^+_1) > 1.26 \\times 10^{22}~\\hbox {year}$$ T 1 / 2 0 ν β β ( 2 1 + ) > 1.26 × 10 22 year .

Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay (\\[2\\nu \\beta \\beta \\]) half-life of \\[^{82}\\]Se as \\[T_{\\smash {1/2}}^{2\\nu } \\!=\\! \\left[ 9.39 \\pm 0.17\\left( \\text{ stat }\\right) \\pm 0.58\\left( \\text{ syst }\\right) \\right] \\times 10^{19}\\] y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is \\[\\left| M^{2\\nu }\\right| = 0.0498 \\pm 0.0016\\]. In addition, a search for neutrinoless double beta decay (\\[0\\nu \\beta \\beta \\]) using 0.93 kg of \\[^{82}\\]Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of \\[T_{1/2}^{0\\nu } > 2.5 \\times 10^{23} \\,\\text{ y } \\,(90\\%\\,\\text{ C.L. })\\] for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of \\[\\langle m_{\\nu } \\rangle < \\left( 1.2{-}3.0\\right) \\,\\text{ eV }\\], where the range reflects \\[0\\nu \\beta \\beta \\] nuclear matrix element values from different calculations. Furthermore, constraints on lepton number violating parameters for other \\[0\\nu \\beta \\beta \\] mechanisms, such as right-handed currents, majoron emission and R-parity violating supersymmetry modes have been set.

We report on the strategy used to optimize the sensitivity of our search for a neutron electric dipole moment at the Paul Scherrer Institute. Measurements were made upon ultracold neutrons stored within a single chamber at the heart of our apparatus. A mercury cohabiting magnetometer together with an array of cesium magnetometers were used to monitor the magnetic field, which was controlled and shaped by a series of precision field coils. In addition to details of the setup itself, we describe the chosen path to realize an appropriate balance between achieving the highest statistical sensitivity alongside the necessary control on systematic effects. The resulting irreducible sensitivity is better than 1 × 10 −26 e  cm. This contribution summarizes in a single coherent picture the results of the most recent publications of the collaboration.

We present the new spectrometer for the neutron electric dipole moment (nEDM) search at the Paul Scherrer Institute (PSI), called n2EDM. The setup is at room temperature in vacuum using ultracold neutrons. n2EDM features a large UCN double storage chamber design with neutron transport adapted to the PSI UCN source. The design builds on experience gained from the previous apparatus operated at PSI until 2017. An order of magnitude increase in sensitivity is calculated for the new baseline setup based on scalable results from the previous apparatus, and the UCN source performance achieved in 2016.