59058647
COVARIANT DIFFERENTIAL EQUATIONS AND SINGULAR VECTORS IN VIRASORO REPRESENTATIONS
Abstract We give explicit expressions for the singular vectors in highest weight representations of the Virasoro algebra using a precise definition of fusion.
119118347
On Casimir's Ghost

Abstract:We define on the universal enveloping superalgebra of 
$ a nonstandard adjoint action, endowing it with a module structure. This allows, in particular, to construct a bosonic operator which anticommutes with all the fermionic generators and which appears to be the square root of a certain Casimir operator.
17007344
Representatives of the Thom class of a vector bundle
Abstract After a review of several methods designed to produce equivariant cohomology classes, we apply one introduced by Berline et al. (1992) to get a family of representatives of the universal Thom class of a vector bundle. Surprisingly, this family does not contain the representative given by Mathai and Quillen (1986). However, it contains the particularly simple and symmetric representative of Harvey and Lawson (1993).
118499620
Affinity and Fluctuations in a Mesoscopic Noria
We exhibit the invariance of cycle affinities in finite state Markov processes under various natural probabilistic constructions, for instance under conditioning and under a new combinatorial construction that we call “drag and drop”. We show that cycle affinities have a natural probabilistic meaning related to first passage non-equilibrium fluctuation relations that we establish.
121423772
The branching rules of conformal embeddings
After recalling the main properties of a conformal embedding of Lie algebrasg⊃p, which is defined by the equality of the Sugawara central charges on both sides, we launch a systematic study of their branching rules. The bulk of the paper is devoted to the proof of a general formula in the casesu(mn)1⊃su(m)n⊕su(n)m. At the end we give some applications to the construction of modular invariant partition functions.
118577113
Real Time Imaging of Quantum and Thermal Fluctuations: The Case of a Two-Level System
A quantum system in contact with a heat bath undergoes quantum transitions between energy levels upon absorption or emission of energy quanta by the bath. These transitions remain virtual unless the energy of the system is measured repeatedly, even continuously in time. Isolating the two indispensable mechanisms in competition, we describe in a synthetic way the main physical features of thermally activated quantum jumps. Using classical tools of stochastic analysis, we compute in the case of a two-level system the complete statistics of jumps and transition times in the limit when the typical measurement time is small compared to the thermal relaxation time. The emerging picture is that quantum trajectories are similar to those of a classical particle in a noisy environment, subject to transitions à la Kramer in a multi-well landscape, but with a large multiplicative noise.
122921889
SIMULATION OF LOW ENERGY NEUTRON RECOILS WITH GEANT4
12512718
High-resolution X-ray spectroscopy and imaging of the nuclear outflow of the starburst galaxy NGC 253
Aims. Using XMM-Newton  data, we have studied the nuclear outflow of the nearby starburst galaxy NGC 253 in X-rays with respect to its morphology and to spectral variations along the outflow. Methods. We analysed XMM-Newton  RGS spectra, RGS brightness profiles in cross-dispersion direction, narrow-band RGS and EPIC images, and EPIC PN brightness profiles of the nuclear region and of the outflow from NGC 253. Results. We detect a diversity of emission lines along the outflow of NGC 253. This includes the He-like ions of Si, Mg, Ne, and O and their corresponding ions in the next higher ionisation state. Additionally transitions from $\ion{Fe}{xvii}$ and $\ion{Fe}{xviii}$ are prominent. The derived temperatures from line ratios along the outflow range from 0.21 ± 0.01 to 0.79 ± 0.06 keV, and the ratio of $\ion{Fe}{xvii}$ lines indicates a predominantly collisionally ionised plasma. Additionally, we see indications of either a recombining or an underionised plasma in the $\ion{Fe}{xvii}$ line ratio. Derived electron densities are 0.106 ± 0.018 cm -3 for the nuclear region and 0.025 ± 0.003 cm -3 for the outflow region closest to the centre. The RGS image in the $\ion{O}{viii}$ line energy clearly shows the morphology of an outflow extending out to ~750 pc along the southeast minor axis, while the northwest part of the outflow is not seen in $\ion{O}{viii}$ due to the heavy absorption by the galactic disc. This is the first time that the hot wind fluid has been detected directly. The limb brightening in Chandra  and XMM-Newton  EPIC observations is only seen in the energy range that contains the $\ion{Fe}{xvii}$ lines (550-750 eV). In all other energy ranges between 400 and 2000 eV, no clear evidence of limb brightening could be detected.
117460354
Results of the CRESST commissioning Run 2007
G. Angloher, M. Bauer, I. Bavykina, A. Bento, A. Brown, C. Bucci,C. Ciemniak, C. Coppi, G. Deuter, F. von Feilitzsch, D. Hauff, S. Henry, P. Huff, J. Imber, S. Ingleby, C. Isaila, J. Jochum, M. Kiefer, M. Kimmerle, H. Kraus, J.-C. Lanfranchi, R. F. Lang, B. Majorovits, M. Malek, R. McGowan, V. B. Mikhailik, E. Pantic, F. Petricca, S. Pfister, W. Potzel, F. Pröbst, W. Rau, S. Roth, K. Rottler, C. Sailer, K. Schäffner, J. Schmaler, S. Scholl, W. Seidel, L. Stodolsky, A. J. B. Tolhurst, I. Usherov, W. Westphal Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München, Germany Physik-Department E15, Technische Universität München, D-85747 Garching, Germany Department of Physics, University of Oxford, Oxford OX1 3RH, United Kingdom Eberhard-Karls-Universität Tübingen, D-72076 Tübingen, Germany INFN, Laboratori Nazionali del Gran Sasso, I-67010 Assergi, Italy now at: Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München, Germany on leave from: Departamento de Fisica, Universidade de Coimbra, P3004 516 Coimbra, Portugal now at: Department of Physics, Queen’s University,Ontario K7L 3N6, Canada Deceased
122260318
Direct dark matter search with CRESST and EURECA
Abstract The current status of the direct Dark Matter experiments CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) and the planned EURECA (European Underground Rare Event Calorimeter Array) is presented. Both experiments are aimed at the direct detection of WIMPs (Weakly Interacting Massive Particles), potential candidates for the Dark Matter in the universe. New design developments of the cryogenic detectors operated at mK temperatures are investigated to optimize detector performance and to simplify mass production. Thus, CRESST is also providing a basis for the EURECA project, aimed at a ton of cryogenic detectors with a multi-material target.
119283621
Results from 730 kg days of the CRESST-II Dark Matter search
The CRESST-II cryogenic Dark Matter search, aiming at detection of WIMPs via elastic scattering off nuclei in CaWO4 crystals, completed 730 kg days of data taking in 2011. We present the data collected with eight detector modules, each with a two-channel readout; one for a phonon signal and the other for coincidently produced scintillation light. The former provides a precise measure of the energy deposited by an interaction, and the ratio of scintillation light to deposited energy can be used to discriminate different types of interacting particles and thus to distinguish possible signal events from the dominant backgrounds.Sixty-seven events are found in the acceptance region where a WIMP signal in the form of low energy nuclear recoils would be expected. We estimate background contributions to this observation from four sources: (1) “leakage” from the e/γ-band (2) “leakage” from the α-particle band (3) neutrons and (4) 206Pb recoils from 210Po decay. Using a maximum likelihood analysis, we find, at a statistical significance of more than 4σ, that these sources alone are not sufficient to explain the data. The addition of a signal due to scattering of relatively light WIMPs could account for this discrepancy, and we determine the associated WIMP parameters.