Anomalous dynamics characterized by non-Gaussian probability distributions (PDFs) and/or temporal long-range correlations can cause subtle modifications of conventional fluctuation relations. As prototypes we study three variants of a generic time-fractional Fokker-Planck equation with constant force. Type A generates superdiffusion, type B subdiffusion and type C both super- and subdiffusion depending on parameter variation. Furthermore type C obeys a fluctuation-dissipation relation whereas A and B do not. We calculate analytically the position PDFs for all three cases and explore numerically their strongly non-Gaussian shapes. While for type C we obtain the conventional transient work fluctuation relation, type A and type B both yield deviations by featuring a coefficient that depends on time and by a nonlinear dependence on the work. We discuss possible applications of these types of dynamics and fluctuation relations to experiments.
The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of $^{76}$Ge. The Majorana Parts Tracking Database is used to record the history of components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Transportation, storage, and processes undergone by parts such as machining or cleaning are linked to part records. Tracking parts provides a great logistics benefit and an important quality assurance reference during construction. In addition, the location history of parts provides an estimate of their exposure to cosmic radiation. A web application for data entry and a radiation exposure calculator have been developed as tools for achieving the extreme radio-purity required for this rare decay search.
In June 2012, an Expression of Interest for a long-baseline experiment (LBNO) has been submitted to the CERN SPSC. LBNO considers three types of neutrino detector technologies: a double-phase liquid argon (LAr) TPC and a magnetised iron detector as far detectors. For the near detector, a high-pressure gas TPC embedded in a calorimeter and a magnet is the baseline design. A mandatory milestone is a concrete prototyping effort towards the envisioned large-scale detectors, and an accompanying campaign of measurements aimed at assessing the detector associated systematic errors. The proposed $6times 6times 6$m$^3$ DLAr is an industrial prototype of the design discussed in the EoI and scalable to 20 kton or 50~kton. It is to be constructed and operated in a controlled laboratory and surface environment with test beam access, such as the CERN North Area (NA). Its successful operation and full characterisation will be a fundamental milestone, likely opening the path to an underground deployment of larger detectors. The response of the DLAr demonstrator will be measured and understood with an unprecedented precision in a charged particle test beam (0.5-20 GeV/c). The exposure will certify the assumptions and calibrate the response of the detector, and allow to develop and to benchmark sophisticated reconstruction algorithms, such as those of 3-dimensional tracking, particle ID and energy flow in liquid argon. All these steps are fundamental for validating the correctness of the physics performance described in the LBNO EoI.
The T2K experiment studies oscillations of an off-axis muon neutrino beam between the J-PARC accelerator complex and the Super-Kamiokande detector. Special emphasis is placed on measuring the mixing angle theta_13 by observing electron neutrino appearance via the sub-dominant muon neutrino to electron neutrino oscillation, and searching for CP violation in the lepton sector. The experiment includes a sophisticated, off-axis, near detector, the ND280, situated 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to understand better neutrino interactions at the energy scale below a few GeV. The data collected with the ND280 are used to study charged- and neutral-current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. A key element of the near detector is the ND280 electromagnetic calorimeter (ECal), consisting of active scintillator bars sandwiched between lead sheets and read outwith multi-pixel photon counters (MPPCs). The ECal is vital to the reconstruction of neutral particles, and the identification of charged particle species. The ECal surrounds the Pi-0 detector (P0D) and the tracking region of the ND280, and is enclosed in the former UA1/NOMAD dipole magnet. This paper describes the design, construction and assembly of the ECal, as well as the materials from which it is composed. The electronic and data acquisition (DAQ) systems are discussed, and performance of the ECal modules, as deduced from measurements with particle beams, cosmic rays, the calibration system, and T2K data, is described.
The NASA Exoplanet Program Analysis Group (ExoPAG) has undertaken an effort to define mission Level 1 requirements for exoplanet direct detection missions at a range of sizes. This report outlines the science goals and requirements for the next exoplanet flagship imaging and spectroscopy mission as determined by the flagship mission Study Analysis Group (SAG) of the NASA Exoplanet Program Analysis Group (ExoPAG). We expect that these goals and requirements will be used to evaluate specific architectures for a future flagship exoplanet imaging and spectroscopy mission, and we expect this effort to serve as a guide and template for similar goals and requirements for smaller missions, an effort that we expect will begin soon. These goals and requirements were discussed, determined, and documented over a 1 year period with contributions from approximately 60 volunteer exoplanet scientists, technologists, and engineers. Numerous teleconferences, emails, and several in-person meetings were conducted to progress on this task, resulting in creating and improving drafts of mission science goals and requirements. That work has been documented in this report as a set of science goals, more detailed objectives, and specific requirements with deliberate flow-down and linkage between each of these sets. The specific requirements have been developed in two categories: Musts are nonnegotiable hard requirements, while Discriminator requirements assign value to performance in areas beyond the floor values set by the Musts. We believe that this framework and content will ensure that this report will be valuable when applied to future mission evaluation activities. We envision that any future exoplanet imaging flagship mission must also be capable of conducting a broad range of other observational astrophysics. We expect that this will be done by the NASA Cosmic Origins Program Analysis Group (COPAG).
Fibre-fed spectrographs now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached has often been pinpointed as one of the major issues associated with the use of fibres. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam-switching, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on sky subtraction can be reached, provided that the cross beam-switching mode is used. This is very encouraging with regard to the detection of very faint sources with future fibre-fed spectrographs, such as VLT/MOONS or E-ELT/MOSAIC.
Based on a data sample of 106 M $psi^{prime}$ events collected with the BESIII detector, the decays $psi^{prime}argammachi_{c0, 2}$,$chi_{c0, 2}argammagamma$ are studied to determine the two-photon widths of the $chi_{c0, 2}$ states. The two-photon decay branching fractions are determined to be ${cal B}(chi_{c0}argammagamma) = (2.24pm 0.19pm 0.12pm 0.08)times 10^{-4}$ and ${cal B}(chi_{c2}argammagamma) = (3.21pm 0.18pm 0.17pm 0.13)times 10^{-4}$. From these, the two-photon widths are determined to be $Gamma_{gamma gamma}(chi_{c0}) = (2.33pm0.20pm0.13pm0.17)$ keV, $Gamma_{gamma gamma}(chi_{c2}) = (0.63pm0.04pm0.04pm0.04)$ keV, and $cal R$ $=Gamma_{gamma gamma}(chi_{c2})/Gamma_{gamma gamma}(chi_{c0})=0.271pm 0.029pm 0.013pm 0.027$, where the uncertainties are statistical, systematic, and those from the PDG ${cal B}(psi^{prime}argammachi_{c0,2})$ and $Gamma(chi_{c0,2})$ errors, respectively. The ratio of the two-photon widths for helicity $lambda=0$ and helicity $lambda=2$ components in the decay $chi_{c2}argammagamma$ is measured for the first time to be $f_{0/2} =Gamma^{lambda=0}_{gammagamma}(chi_{c2})/Gamma^{lambda=2}_{gammagamma}(chi_{c2}) = 0.00pm0.02pm0.02$.
The decays $J/psito pbar{p}$ and $J/psito nbar{n}$ have been investigated with a sample of 225.2 million $J/psi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider. The branching fractions are determined to be $mathcal{B}(J/psito pbar{p})=(2.112pm0.004pm0.031)times10^{-3}$ and $mathcal{B}(J/psito nbar{n})=(2.07pm0.01pm0.17)times10^{-3}$. Distributions of the angle $theta$ between the proton or anti-neutron and the beam direction are well described by the form $1+alphacos^2theta$, and we find $alpha=0.595pm0.012pm0.015$ for $J/psito pbar{p}$ and $alpha=0.50pm0.04pm0.21$ for $J/psito nbar{n}$. Our branching-fraction results suggest a large phase angle between the strong and electromagnetic amplitudes describing the $J/psito Nbar{N}$ decay.
The X-ray spectra of Active Galactic Nuclei (AGN) carry the signatures of the emission from the central region, close to the Super Massive Black Hole (SMBH). For this reason, the study of deep X-ray spectra is a powerful instrument to investigate the origin of their emission. The emission line most often observed in the X-ray spectra of AGN is Fe K. It is known that it can be broadened and deformed by relativistic effects if emitted close enough to the central SMBH. In recent statistical studies of the X-ray spectra of AGN samples, it is found that a narrow Fe line is ubiquitous, while whether the broad features are as common is still uncertain. We present here the results of an investigation on the characteristics of the Fe line in the average X-ray spectra of AGN in deep Chandra fields. The average spectrum of the AGN is computed using Chandra spectra with more than 200 net counts from the AEGIS, Chandra Deep Field North and Chandra Deep Field South surveys. The sample spans a broader range of X-ray luminosities than other samples studied with stacking methods up to z=3.5. We analyze the average spectra of this sample using our own averaging method, checking the results against extensive simulations. Subsamples defined in terms of column density of the local absorber, luminosity and z are also investigated. We found a very significant Fe line with a narrow profile in all our samples and in almost all the subsamples that we constructed. The equivalent width (EW) of the narrow line estimated in the average spectrum of the full sample is 74 eV. The broad line component is significantly detected in the subsample of AGN with L<1.43 1E44 cgs and z<0.76, with EW=108 eV. We concluded that the narrow Fe line is an ubiquitous feature of the X-ray spectra of the AGN up to z=3.5.The broad line component is significant in the X-ray spectra of the AGN with low luminosity and low z.
In this paper we advance physical background of the energy- and flux-budget turbulence closure based on the budget equations for the turbulent kinetic and potential energies and turbulent fluxes of momentum and buoyancy, and a new relaxation equation for the turbulent dissipation time-scale. The closure is designed for stratified geophysical flows from neutral to very stable and accounts for the Earth rotation. In accordance to modern experimental evidence, the closure implies maintaining of turbulence by the velocity shear at any gradient Richardson number Ri, and distinguishes between the two principally different regimes: strong turbulence at Ri << 1 typical of boundary-layer flows and characterised by the practically constant turbulent Prandtl number; and weak turbulence at Ri > 1 typical of the free atmosphere or deep ocean, where the turbulent Prandtl number asymptotically linearly increases with increasing Ri (which implies very strong suppression of the heat transfer compared to the momentum transfer). For use in different applications, the closure is formulated at different levels of complexity, from the local algebraic model relevant to the steady-state regime of turbulence to a hierarchy of non-local closures including simpler down-gradient models, presented in terms of the eddy-viscosity and eddy-conductivity, and general non-gradient model based on prognostic equations for all basic parameters of turbulence including turbulent fluxes.
