B. Schneider

The GERDA experiment searches for the lepton-number-violating neutrinoless double-β decay of 76Ge (76Ge→76Se+2e−) operating bare Ge diodes with an enriched 76Ge fraction in liquid argon. The exposure for broad-energy germanium type (BEGe) detectors is increased threefold with respect to our previous data release. The BEGe detectors feature an excellent background suppression from the analysis of the time profile of the detector signals. In the analysis window a background level of 1.0+0.6−0.4×10−3 counts/(keV kg yr) has been achieved; if normalized to the energy resolution this is the lowest ever achieved in any 0νββ experiment. No signal is observed and a new 90% C.L. lower limit for the half-life of 8.0×1025 yr is placed when combining with our previous data. The expected median sensitivity assuming no signal is 5.8×1025 yr.Received 17 November 2017Revised 23 January 2018DOI:https://doi.org/10.1103/PhysRevLett.120.132503© 2018 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDouble beta decayNeutrinoless double beta decayNuclear structure & decaysPropertiesBaryon & lepton number symmetriesNuclear Physics

The total photoproduction cross section is determined from a measurement of electroproduction with the ZEUS detector at HERA. The Q2 values of the virtual photons are in the range 10−7<Q2<2×10−2 GeV2. The γp total cross section in the γp centre of mass energy range 186–233 GeV is 154 ± 16 (stat.) ± 32 (syst.) μb.

A measurement of event-plane correlations involving two or three event planes of different order is presented as a function of centrality for 7 μb−1 Pb+Pb collision data at sNN=2.76 TeV, recorded by the ATLAS experiment at the Large Hadron Collider. Fourteen correlators are measured using a standard event-plane method and a scalar-product method, and the latter method is found to give a systematically larger correlation signal. Several different trends in the centrality dependence of these correlators are observed. These trends are not reproduced by predictions based on the Glauber model, which includes only the correlations from the collision geometry in the initial state. Calculations that include the final-state collective dynamics are able to describe qualitatively, and in some cases also quantitatively, the centrality dependence of the measured correlators. These observations suggest that both the fluctuations in the initial geometry and the nonlinear mixing between different harmonics in the final state are important for creating these correlations in momentum space.8 MoreReceived 3 March 2014DOI:https://doi.org/10.1103/PhysRevC.90.024905Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.©2014 CERN, for the ATLAS Collaboration

In a magnetic field along a $〈111〉$ axis, dysprosium aluminum garnet (DAG) closely resembles a two-sublattice Ising antiferromagnet, and it undergoes a transition to the paramagnetic state without spin flopping. To investigate the nature of this transition, high-resolution measurements have been made of the isothermal magnetization and the specific heat ${C}_{H}$ as a function of temperature from 1.1 to 4.2 \ifmmode^\circ\else\textdegree\fi{}K in magnetic fields up to 14 kOe. A number of additional measurements have also been made down to 0.5 \ifmmode^\circ\else\textdegree\fi{}K and between 4.2 and 8 \ifmmode^\circ\else\textdegree\fi{}K. Small lattice contributions to the specific heat were estimated from separate measurements on yttrium and lutetium aluminum garnets. The magnetic measurements were made on a small spherical crystal and the thermal measurements were made on a large ellipsoidal single crystal with a demagnetizing factor $N=5.35$. The two sets of data are shown to be consistent if the expected shape dependence is taken into account, and the principal results are converted to correspond to the ideal case of $N=0$. The analysis indicates that the transition is of first order below 1.66 \ifmmode^\circ\else\textdegree\fi{}K, with a region of coexistence between the antiferromagnetic and paramagnetic phases, depending on sample shape. The corresponding latent heat was measured directly and compared with the predictions of the magnetic Clausius-Clapeyron equation. Between 1.66 and 2.53 \ifmmode^\circ\else\textdegree\fi{}K the transition is higher than first order and unusual in form, with fairly sharp but finite maxima in the specific heat and only mild inflections in the magnetic isotherms. A complete phase diagram was constructed, and the principal thermodynamic functions (internal energy, entropy, and enthalpy) were derived. Possible applications of DAG to low-temperature heat engines are discussed briefly. The phase diagram corresponding to $N=0$ shows a general similarity to the phase diagram for ${\mathrm{He}}^{3}$-${\mathrm{He}}^{4}$ mixtures, but the analogy is complicated by long-range dipolar forces, known to be significant in the present case.

A discovery that neutrinos are Majorana fermions would have profound implications for particle physics and cosmology. The Majorana character of neutrinos would make possible the neutrinoless double-β (0νββ) decay, a matter-creating process without the balancing emission of antimatter. The GERDA Collaboration searches for the 0νββ decay of 76Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg⋅year, we observe no signal and derive a lower half-life limit of T1/2 > 0.9 × 1026 years (90% C.L.). Our T1/2 sensitivity, assuming no signal, is 1.1 × 1026 years. Combining the latter with those from other 0νββ decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 to 0.16 electron volts.

The successful operation of the Large Hadron Collider (LHC) and the excellent performance of the ATLAS, CMS, LHCb and ALICE detectors in Run-1 and Run-2 with $pp$ collisions at center-of-mass energies of 7, 8 and 13 TeV as well as the giant leap in precision calculations and modeling of fundamental interactions at hadron colliders have allowed an extraordinary breadth of physics studies including precision measurements of a variety physics processes. The LHC results have so far confirmed the validity of the Standard Model of particle physics up to unprecedented energy scales and with great precision in the sectors of strong and electroweak interactions as well as flavour physics, for instance in top quark physics. The upgrade of the LHC to a High Luminosity phase (HL-LHC) at 14 TeV center-of-mass energy with 3 ab$^{-1}$ of integrated luminosity will probe the Standard Model with even greater precision and will extend the sensitivity to possible anomalies in the Standard Model, thanks to a ten-fold larger data set, upgraded detectors and expected improvements in the theoretical understanding. This document summarises the physics reach of the HL-LHC in the realm of strong and electroweak interactions and top quark physics, and provides a glimpse of the potential of a possible further upgrade of the LHC to a 27 TeV $pp$ collider, the High-Energy LHC (HE-LHC), assumed to accumulate an integrated luminosity of 15 ab$^{-1}$.

Extensive earlier work has indicated that dysprosium aluminum garnet (DAG) in a magnetic field along a (111) axis should approximate to a two-sublattice Ising-model antiferromagnet, and in this paper we examine this correspondence critically. Quantitative estimates are derived for the differences between the ideal model and the real material, and it is shown that they are in fact very small and that appropriate corrections can be applied to allow for most of the deviations. General expressions based on the Ising model are derived for the magnetization, differential susceptibility, and specific heat in field and temperature regions where exact asymptotic expansions are valid, and these are fitted to available experimental data on DAG. The results of the analysis can be expressed in terms of two sets of parameters which describe, respectively, the single-ion properties and combinations of the spin-spin interactions. The relation of these parameters to the microscopic Hamiltonian is deferred to a later paper, but a number of empirical cross checks indicate excellent consistency in the results. In addition, a number of parameters describing the cooperative behavior are extracted from the experimental data and there is a discussion of some of the general problems of analyzing critical-point data. The significance of most of these parameters must await further theoretical work on Ising models with competing and long-range interactions.

A search for neutrinoless $\beta\beta$ decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 10$^{23}$ yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with $^{76}$Ge. A new result for the half-life of the neutrino-accompanied $\beta\beta$ decay of $^{76}$Ge with significantly reduced uncertainties is also given, resulting in $T^{2\nu}_{1/2} = (1.926 \pm 0.095)\cdot10^{21}$ yr.

A new microfluidic assembly method for semiconductor‐based biosensors using 3D‐printing technologies was proposed for a rapid and cost‐efficient design of new sensor systems. The microfluidic unit is designed and printed by a 3D‐printer in just a few hours and assembled on a light‐addressable potentiometric sensor (LAPS) chip using a photo resin. The cell growth curves obtained from culturing cells within microfluidics‐based LAPS systems were compared with cell growth curves in cell culture flasks to examine biocompatibility of the 3D‐printed chips. Furthermore, an optimal cell culturing within microfluidics‐based LAPS chips was achieved by adjusting the fetal calf serum concentrations of the cell culture medium, an important factor for the cell proliferation.

The GERDA collaboration is performing a sensitive search for neutrinoless double beta decay of $^{76}$Ge at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the GERDA experiment from Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved. GERDA is thus the first experiment that will remain background-free up to its design exposure (100 kg yr). It will reach thereby a half-life sensitivity of more than 10$^{26}$ yr within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.

Dysprosium aluminum garnet is a highly anisotropic (Ising-like) antiferromagnet which, in an applied field, undergoes a transition to the paramagnetic state without spin flopping. To investigate the nature of this transition we have made high-resolution measurements of the isothermal magnetization M and we have measured the specific heat CH as a function of temperature in different constant magnetic fields up to 14 kOe. The results show that for temperatures between 1.66°K and 1.14°K (and probably below) the transition is of first order, with dM/dH accurately constant and equal to 1/D, where D is the demagnetizing factor. The latent heat corresponding to this first-order phase change was calculated from the Clausius-Clapeyron equation and compared with direct measurements of the isothermal heat of transformation. Good agreement was found. From 1.66°K up to the Néel point (TN=2.53°K) the transition is of higher than first order with a point of inflection in the M(H) isotherms and slightly rounded λ-type peaks in the CH(T) curves. Close to TN the phase boundary is found to fit Hcint=A(1−T/TN)n, with n=0.50±0.02 and A=6.52 kOe. Our results show that the theory of a simple Ising model with nearest-neighbor interactions is only partially successful in predicting the behavior of a real material which also has magnetic dipole interactions.

Abstract The dispersion equations of magnetostatic spin wave modes in thin ferromagnetic plates are derived within the linear phenomenological theory for a general anisotropic tensor of the dynamic susceptibility (Polder tensor). The equations are discussed for the two special cases of the effective magnetic field being parallel or perpendicular to the surface of the plate. In the Appendix the Polder tensor is derived for crystals with an anisotropic gyromagnetic ratio.

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at $$ \sqrt{s} $$ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured.

An optimized digital shaping filter has been developed for the Gerda experiment which searches for neutrinoless double beta decay in $$^{76}$$ Ge. The Gerda Phase I energy calibration data have been reprocessed and an average improvement of 0.3 keV in energy resolution (FWHM) corresponding to 10 % at the $$Q$$ value for $$0\nu \beta \beta $$ decay in $$^{76}$$ Ge is obtained. This is possible thanks to the enhanced low-frequency noise rejection of this Zero Area Cusp (ZAC) signal shaping filter.

The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0νββ) in 76Ge, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). In the first phase of the experiment, a 90% confidence level (C.L.) sensitivity of 2.4⋅1025 yr on the 0νββ decay half-life was achieved with a 21.6 kg⋅yr exposure and an unprecedented background index in the region of interest of 10−2 counts/(keV⋅kg⋅yr). No excess of signal events was found, and an experimental lower limit on the half-life of 2.1 ⋅ 1025 yr (90% C.L.) was established. Correspondingly, the limit on the effective Majorana neutrino mass is mee<0.2–0.4 eV, depending on the considered nuclear matrix element. The previous claim for evidence of a 0νββ decay signal is strongly disfavored, and the field of research is open again.

The GERmanium Detector Array (Gerda) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double-beta decay of 76 Ge into 76 Se+2e - . Gerda has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new 76Ge enriched detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the Hades underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for Gerda Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the accuracy of pulse shape simulation codes.

The Gerda experiment at Lngs of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66 PMTs in the water tank surrounding the Gerda cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two causes have been identified: (i) secondary muons from the Cngs neutrino beam (2.2%) and (ii) a temperature modulation of the atmosphere (1.4%). A mean cosmic muon rate of Iμ0=(3.477±0.002stat±0.067sys)×10−4/(s · m2) was found in good agreement with other experiments at Lngs. Combining the present result with those from previous experiments at Lngs the effective temperature coefficient αT,Lngs is determined to 0.93 ± 0.03. A fit of the temperature coefficients measured at various underground sites yields a kaon to pion ratio rK/π of 0.10 ± 0.03.

A number of experimental measurements on dysprosium aluminum garnet are combined to estimate the relative importance of non-dipolar contributions to the magnetic interactions. The main term is shown to be an enhancement (∼50%) of the Ising-like dipoke coupling between nearest neighbors.

Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of $$^{36}$$ Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of $$^{36}$$ Ar was established: $$T_{1/2} > $$ 3.6 $$\times $$ 10 $$^{21}$$ years at 90% CI.

Two neutrino double beta decay of $^{76}$Ge to excited states of $^{76}$Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in $^{76}$Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation $\gamma$ ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: ${0^+_{\rm g.s.}-2^+_1}$: $T^{2\nu}_{1/2}>$1.6$\cdot10^{23}$ yr, ${0^+_{\rm g.s.}-0^+_1}$: $T^{2\nu}_{1/2}>$3.7$\cdot10^{23}$ yr and ${0^+_{\rm g.s.}-2^+_2}$: $T^{2\nu}_{1/2}>$2.3$\cdot10^{23}$ yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the ${0^+_{\rm g.s.}-0^+_1}$ transition.

Motivated by the success of the flavour physics programme carried out over the last decade at the Large Hadron Collider (LHC), we characterize in detail the physics potential of its High-Luminosity and High-Energy upgrades in this domain of physics. We document the extraordinary breadth of the HL/HE-LHC programme enabled by a putative Upgrade II of the dedicated flavour physics experiment LHCb and the evolution of the established flavour physics role of the ATLAS and CMS general purpose experiments. We connect the dedicated flavour physics programme to studies of the top quark, Higgs boson, and direct high-$p_T$ searches for new particles and force carriers. We discuss the complementarity of their discovery potential for physics beyond the Standard Model, affirming the necessity to fully exploit the LHC's flavour physics potential throughout its upgrade eras.

The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 "telescopes", with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run 2 (2015-18) of the LHC, as well as preparations for Run 3, which will begin in 2022.

Abstract The magnetostatic spin wave mode transmission through anisotropic rectangular slabs of YIG has been investigated experimentally and dispersion curves have been derived. The experimental results are interpreted by an approximate application of the theory developed in a former paper. The agreement between theoretical and experimental results is rather good.

The GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay ([Formula: see text]) of [Formula: see text]Ge. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a “bare” mode and immersed in liquid argon. The overall background level of [Formula: see text] was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the [Formula: see text] decay of [Formula: see text]Ge [Formula: see text] yr (90% CL), while the corresponding median sensitivity was [Formula: see text] yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to [Formula: see text]. After analyzing 23.2 kg[Formula: see text]⋅[Formula: see text]yr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the [Formula: see text]Ge [Formula: see text] decay was obtained: [Formula: see text] yr (90% CL), reaching a sensitivity of [Formula: see text] yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg[Formula: see text]yr. If no signal is found by then the GERDA sensitivity will have reached [Formula: see text] yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of [Formula: see text] decay of [Formula: see text]Ge will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of [Formula: see text]Ge. After ten years of data taking, it will reach a sensitivity beyond 10[Formula: see text] yr, and hence fully cover the inverted hierarchy region.

A search for direct chargino and neutralino production processes is presented in a final state with exactly 3 leptons (electrons or muons). No excess over the Standard Model has been observed. The analysis presented is based on 20.7 fb−1 of proton-proton collision data delivered by the LHC at √(s) = 8 TeV and recorded by the ATLAS [2] detector in 2012. [1]

Internal contaminations of $^{238}$U, $^{235}$U and $^{232}$Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of $^{76}$Ge. The data from GERDA Phase~I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for $^{226}$Ra, $^{227}$Ac and $^{228}$Th, the long-lived daughter nuclides of $^{238}$U, $^{235}$U and $^{232}$Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from $^{226}$Ra and $^{228}$Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.

Abstract The GERmanium Detector Array (Gerda) experiment located at the INFN Gran Sasso Laboratory (Italy), is looking for the neutrinoless double beta decay of 76 Ge, by using high-purity germanium detectors made from isotopically enriched material. The combination of the novel experimental design, the careful material selection for radio-purity and the active/passive shielding techniques result in a very low residual background at the Q-value of the decay, about 10 −3 cts/(keV-kg-yr). This makes GERDA the first experiment in the field to be background-free for the complete design exposure of 100 kg-yr. A search for neutrinoless double beta decay was performed with a total exposure of 46.7 kg-yr: 23.2 kg-yr come from the second phase (Phase II) of the experiment, in which the background is reduced by about a factor of ten with respect to the previous phase. The analysis presented in this paper includes 12.4 kg-yr of new Phase II data. No evidence for a possible signal is found: the lower limit for the half-life of 76 Ge is 8.0 • 10 25 yr at 90% CL. The experimental median sensitivity is 5.8 • 10 25 yr. The experiment is currently taking data. As it is running in a background-free regime, its sensitivity grows linearly with exposure and it is expected to surpass 10 26 yr within 2018.

The spin-wave power transmission through a hybrid sample of YIG and InSb has been measured as a function of magnetic field strength H0 (0–1500 Oe), frequency f (1.5–4 GHz), and temperature T (150°–340°K). In the range of magnetostatic volume modes, a strong absorption of spin-wave power caused by the electrons in InSb has been found. The magnetic field H* of maximum absorption depends on f and T in a way which can be explained by the assumption of spin-wave-helicon interaction.

The Beam Instrumentation group of the European Organization for Nuclear Research (CERN) has been developing an instrument called the Beam Wire Scanner (BWS) for the past few years. This system is used to measure the size of proton beams in the Large Hadron Collider (LHC) and its injector chain. An electro-mechanical system moves a very thin wire of 30 μm through the particle beam and measures the induced radiation losses generated by this interaction. The actuator, based on a Permanent Magnet Synchronous Motor (PMSM), a solid rotor resolver and an in-house designed high precision optical encoder are located in underground installations and have to cope with large irradiation levels. Another difference with respect to its predecessors is the placement of all moving parts in the vacuum. The control electronics is situated far away from the beam tunnels to minimize the destructive impact of ionizing particles. Challenges arise from the long distance between these two parts, up to 250 meters, and the high scanning speed of the wire of up to 20 ms <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> , with a target position accuracy as low as 5 μm rms. This paper describes the challenges of the BWS design, details the current status and introduces the philosophy of its conception to the IEEE control application community.

In a hybrid sample composed of a ferrimagnetic YIG plate and a semiconducting InSb plate, a magnetostatic spin wave propagating along the ferrimagnetic plate exercises a drag on the electrons in the semiconductor plate. The resulting magnon drag voltage has been investigated as a function of applied magnetic field strength (0 to 3.5 kOe), spin wave power (5 to 500 μW), sample temperature (4 to 300 K), and frequency (1 to 3 GHz). The experimental results above 30 K could be explained by a theoretical treatment. This is based on the assumption of a non-linearity in the field equations caused by the magnetic field dependence of the conductivity tensor for the semiconductor. In einer hybriden Probe, die aus einer ferrimagnetischen YIG-Platte und einer halbleitenden InSb-Platte zusammengesetzt ist, führt eine magnetostatische Spinwelle, die sich längs der ferrimagnetischen Platte fortpflanzt, Elektronen in der angrenzenden Halbleiterplatte mit. Die resultierende Magnon-Mitführungsspannung wurde als Funktion der angelegten Magnetfeldstärke (0 bis 3,5 kOe), der Spinwellenleistung (5 bis 500 μW), der Probentemperatur (4 bis 300 K) und der Frequenz (1 bis 3 GHz) untersucht. Die experimentellen Ergebnisse oberhalb 30 K wurden durch eine theoretische Behandlung gedeutet. Diese ist auf die Annahme einer Nichtlinearität der Feldgleichungen gegründet, die auf der Magnetfeldabhängigkeit des Leitfähigkeitstensors des Halbleiters beruht.

An optimized digital shaping filter has been developed for the GERDA experiment which searches for neutrinoless double beta decay in 76Ge. The GERDA Phase I energy calibration data have been reprocessed and an average improvement of 0.3 keV in energy resolution (FWHM) at the 76Ge Q value for 0\nu\beta\beta decay is obtained. This is possible thanks to the enhanced low-frequency noise rejection of this Zero Area Cusp (ZAC) signal shaping fillter.

The observation of neutrinoless double beta decay would allow to shed light onto the particle nature of neutrinos. Gerda is aiming to perform a background-free search for this process using high purity germanium detectors enriched in 76Ge operated in liquid argon. This goal relies on the application of active background suppression techniques. A low background light instrumentation has been installed for Phase II to detect events with coincident energy deposition in the nearby liquid argon. The intended background index of ∼10−3 cts/(keV·ky·yr) has been confirmed.

The Gerda experiment, located at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy, searches for the neutrinoless double beta (0νββ) decay of 76Ge. Gerda Phase II is aiming to reach a sensitivity for the 0νββ half life of 1026 yr in ∼ 3 years of physics data taking with 100 kg·yr of exposure and a background index of ∼ 10−3 cts/(keV·kg·yr). After 6 months of acquisition a first data release with 10.8 kg·yr of exposure is performed, showing that the design background is achieved. In this work a study of the Phase II background spectrum, the main spectral structures and the background sources will be presented and discussed.

Gerda is designed for a background-free search of 76Ge neutrinoless double-β decay, using bare Ge detectors in liquid Ar. The experiment was upgraded after the successful completion of Phase I to double the target mass and further reduce the background. Newly-designed Ge detectors were installed along with LAr scintillation sensors. Phase II of data-taking started in Dec 2015 with approximately 36 kg of Ge detectors and is currently ongoing. The first results based on 10.8 kg· yr of exposure are presented. The background goal of 10−3 cts/(keV· kg· yr) is achieved and a search for neutrinoless double-β decay is performed by combining Phase I and II data. No signal is found and a new limit is set at yr (90% C.L.).

The GERmanium Detector Array (GERDA) experiment located at the INFN Gran Sasso Laboratory (Italy), is looking for the neutrinoless double beta decay of Ge76, by using high-purity germanium detectors made from isotopically enriched material. The combination of the novel experimental design, the careful material selection for radio-purity and the active/passive shielding techniques result in a very low residual background at the Q-value of the decay, about 1e-3 counts/(keV kg yr). This makes GERDA the first experiment in the field to be background-free for the complete design exposure of 100 kg yr. A search for neutrinoless double beta decay was performed with a total exposure of 47.7 kg yr: 23.2 kg yr come from the second phase (Phase II) of the experiment, in which the background is reduced by about a factor of ten with respect to the previous phase. The analysis presented in this paper includes 12.4 kg yr of new Phase II data. No evidence for a possible signal is found: the lower limit for the half-life of Ge76 is 8.0e25 yr at 90% CL. The experimental median sensitivity is 5.8e25 yr. The experiment is currently taking data. As it is running in a background-free regime, its sensitivity grows linearly with exposure and it is expected to surpass 1e26 yr within 2018.

Let G be a cubic graph of order 2n consisting of a cycle plus a perfect matching and let G∗ be the symmetric digraph obtained from G by replacing each edge of G by two opposite arcs. In this paper we study when G∗ can be decomposed into three hamiltonian circuits and in particular we prove that such a decomposition is impossible if n is even. Soit G un graphe cubique d'ordre 2n, formé de l'union d'un cycle et d'un couplage parfait. Soit G∗ le graphe orienté symétrique obtenu en remplaçant chaque arête de G par deux arcs opposés. Dans cet article, nous nous intéressons aux décompositions de G∗ en 3 circuits hamiltoniens; en particulier, nous montrons que si n est pair, une telle décomposition est impossible.

The design and construction of the ZEUS forward tracking detector is described. The detector consists of three large planar drift chambers mounted in the forward direction with respect to the proton beam and a smaller rear detector of the same type. Test beam measurements performed at DESY show a single wire spatial resolution of 105 μm and a dEdx resolution of 8.8%. The resolution of the three-dimensional track coordinates and slopes provided by one chamber are found to be 90 μm and 2.7 mrad, respectively.

The GERmanium Detector Array (GERDA) experiment, located at the Gran Sasso underground laboratory in Italy, is built for the search of $0\nu\beta\beta$ decay in $^{76}$Ge. GERDA operates bare high purity germanium detectors submersed in liquid Argon (LAr). Phase I of the experiment was completed reaching an exposure of about 21 kg$\cdot$yr with a background level of $10^{-2}$ cts/(ke V $\cdot$ kg $\cdot$ yr). GERDA Phase I set a limit on the $0\nu\beta\beta$ decay of $^{76}$Ge of $T_{1/2}^{0\nu} > 2.1 \cdot 10^{25}$ yr. In Phase II 35 kg of germanium detectors enriched in $^{76}$Ge are operated to reach an exposure of 100 kg$\cdot$yr. The design goal is to reduce the background by one order of magnitude to reach the sensitivity for $T_{1/2}^{0\nu} = \mathcal{O} (10^{26} )$ yr. The Phase II setup comprises thirty newly produced Broad Energy Germanium (BEGe) detectors. They contribute to the background reduction with better energy resolution and enhanced pulse shape discrimination. To achieve the necessary background reduction, the setup was complemented with LAr veto. The hardware upgrade for Phase II was finished and all detectors were deployed in December 2015. We present the first results of Phase II with 10.8 kg$\cdot$yr exposure reached in June 2016.

This Letter presents the results of a search for a heavy particle decaying into an e(+/-)mu(+/-), e(+/-)tau(+/-), or mu(+/-)tau(+/-) final state in pp collisions at root s = 7 TeV. The data were recorded with the ATLAS detector at the LHC during 2011 and correspond to an integrated luminosity of 4.6 fb(-1). No significant excess above the Standard Model expectation is observed, and exclusions at 95% confidence level are placed on the cross section times branching ratio for the production of an R-parity-violating supersymmetric tau sneutrino. For a sneutrino mass of 500 (2000) GeV, the observed limits on the production cross section times branching ratio are 3.2 (1.4) fb, 42 (17) fb, and 40 (18) fb for the e mu, e tau, and mu tau modes, respectively. These results considerably extend constraints from Tevatron experiments.

The Insertable-B-Layer (IBL) is a new pixel detector layer to be installed at the ATLAS experiment at the LHC, CERN in 2013. It will be integrated into the general pixel readout and software framework, hence the off-detector readout electronics has to support the new front-end electronics whilst maintaining a high degree of interoperability to the components of the existing system. The off-detector readout is realised using a number of VME card pairs ROD and BOC plus a VME crate controller and a custom timing distribution system. The main elements of the new BOC design comprise optical interfaces towards the detector, signal conditioning and data recovery logic. We present the demonstrator used to verify the design approach. The demonstrator is based on a XILINX SP605 FPGA evaluation board and uses a Microblaze processor inside the FPGA to provide easy and flexible access to all essential BOC functions and the corresponding emulator modules, which enable full test of the entire BOC functionality even without any external components. However, optical interfaces may be connected via a mezzanine card. We present the details of the emulation circuitries together with measurement results showing the operation of the BOC logic.

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb(-1) of root s = 7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results.

We present a search for a light (mass < 2 GeV) boson predicted by Hidden Valley supersymmetric models that decays into a final state consisting of collimated muons or electrons, denoted lepton-jets. The analysis uses 5 fb(-1) of root s = 7 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider to search for the following signatures: single lepton-jets with at least four muons; pairs of lepton-jets, each with two or more muons; and pairs of lepton-jets with two or more electrons. This study finds no statistically significant deviation from the Standard Model prediction and places 95% confidence-level exclusion limits on the production cross section times branching ratio of light bosons for several parameter sets of a Hidden Valley model.

The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0νββ) in 76Ge, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). GERDA operates bare high purity germanium detectors submersed in liquid Argon (LAr). Phase II of data-taking started in Dec 2015 and is currently ongoing. In Phase II 35 kg of germanium detectors enriched in 76Ge including thirty newly produced Broad Energy Germanium (BEGe) detectors is operating to reach an exposure of 100 kg·yr within about 3 years data taking. The design goal of Phase II is to reduce the background by one order of magnitude to get the sensitivity for . To achieve the necessary background reduction, the setup was complemented with LAr veto. Analysis of the background spectrum of Phase II demonstrates consistency with the background models. Furthermore 226Ra and 232Th contamination levels consistent with screening results. In the first Phase II data release we found no hint for a 0νββ decay signal and place a limit of this process yr (90% C.L., sensitivity 4.0·1025 yr). First results of GERDA Phase II will be presented.

The GERmanium Detector Array (gerda) experiment, located at the Gran Sasso underground laboratory in Italy, is one of the leading experiments for the search of 0νββ decay. In Phase II of the experiment 35.6 kg of enriched germanium detectors are operated. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allowed to reduce the background index to the intended level of 10−3 cts/(keV·kg·yr).In the first five month of data taking 10.8 kg yr of exposure were accumulated. No signal has been found and together with data from Phase I a new limit for the neutrinoless double beta decay half-life of 76Ge of 5.3 · 1025 yr at 90% C.L. was established in June 2016. Phase II data taking is ongoing and will allow the exploration of half-lifes in the 1026 yr regime. The current status of data taking and an update on the background index are presented.

The GERmanium Detector Array (GERDA) experiment, located at the Gran Sasso underground laboratory in Italy, is built for the search of $0\nu\beta\beta$ decay in $^{76}$Ge. GERDA operates bare high purity germanium detectors submersed in liquid Argon (LAr). Phase I of the experiment was completed reaching an exposure of about 21 kg$\cdot$yr with a background level of $10^{-2}$ cts/(ke V $\cdot$ kg $\cdot$ yr). GERDA Phase I set a limit on the $0\nu\beta\beta$ decay of $^{76}$Ge of $T_{1/2}^{0\nu} > 2.1 \cdot 10^{25}$ yr. In Phase II 35 kg of germanium detectors enriched in $^{76}$Ge are operated to reach an exposure of 100 kg$\cdot$yr. The design goal is to reduce the background by one order of magnitude to reach the sensitivity for $T_{1/2}^{0\nu} = \mathcal{O} (10^{26} )$ yr. The Phase II setup comprises thirty newly produced Broad Energy Germanium (BEGe) detectors. They contribute to the background reduction with better energy resolution and enhanced pulse shape discrimination. To achieve the necessary background reduction, the setup was complemented with LAr veto. The hardware upgrade for Phase II was finished and all detectors were deployed in December 2015. We present the first results of Phase II with 10.8 kg$\cdot$yr exposure reached in June 2016.

.

An observation of neutrinoless double beta ([Formula: see text]) decay would allow to shed light onto the nature of neutrinos. Gerda (GERmanium Detector Array) aims to discover this process in a background-free search using [Formula: see text]Ge. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. Bare, isotopically enriched, high purity germanium detectors are operated in liquid argon. Gerda follows a staged approach. In Phase II 35.6 kg of enriched germanium detectors are operated since December 2015. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allows to reduce the background index to the intended level of [Formula: see text] cts/(keV⋅kg⋅yr). No evidence for the [Formula: see text] decay has been found in 23.2 kg⋅yr of Phase II data, and together with data from Phase I the up-to-date most stringent half-life limit for this process in [Formula: see text]Ge has been established, at a median sensitivity of 5.8⋅10[Formula: see text][Formula: see text]yr the 90[Formula: see text]% C.L. lower limit is 8.0⋅10[Formula: see text][Formula: see text]yr.

During the last decades, research on lab-on-a-chip systems has continuously increased systems have multiple functionalities on a single chip, like flow control, triggering and detection of analyte reactions or stimulation of cells.To enhance flexibility and perform different tasks in a single system, light-addressable technologies can be used.E.g., it is possible to use light-addressable hydrogels for flow control, light-addressable potentiometric sensors for sensing and light-addressable electrodes for stimulation inside measurement chambers.These technologies have to be adapted and combined for the integration in a common set-up.In this work, the single technologies will be introduced and the actual progress of combining these technologies into a common analysis platform will be presented.