Thermodynamic properties of thin films of superfluid 3He-A

The pairing correlations in superfluid He-3 are strongly modified by quasiparticle scattering off a surface or an interface. We present theoretical results and predictions for the order parameter, the quasiparticle excitation spectrum and the free energy for thin films of superfluid He-3. Both specular and diffuse scattering by a substrate are considered, while the free surface is assumed to be a perfectly reflecting specular boundary. The results are based on self-consistent calculations of the order parameter and quasiparticle excitation spectrum at zero pressure. We obtain new results for the phase diagram, free energy, entropy and specific heat of thin films of superfluid He-3.Comment: Replaced with an updated versio

Recent advances in neutrinoless double beta decay search

Even after the discovery of neutrino flavour oscillations, based on data from atmospheric, solar, reactor, and accelerator experiments, many characteristics of the neutrino remain unknown. Only the neutrino square-mass differences and the mixing angle values have been estimated, while the value of each mass eigenstate still hasn't. Its nature (massive Majorana or Dirac particle) is still escaping. Neutrinoless double beta decay ($0\nu$-DBD) experimental discovery could be the ultimate answer to some delicate questions of elementary particle and nuclear physics. The Majorana description of neutrinos allows the $0\nu$-DBD process, and consequently either a mass value could be measured or the existence of physics beyond the standard should be confirmed without any doubt. As expected, the $0\nu$-DBD measurement is a very difficult field of application for experimentalists. In this paper, after a short summary of the latest results in neutrino physics, the experimental status, the R&D projects, and perspectives in $0\nu$-DBD sector are reviewed.Comment: 36 pages, 7 figures, To be publish in Czech Journal of Physic

Near-intrinsic energy resolution for 30-662 keV gamma rays in a high pressure xenon electroluminescent TPC

We present the design, data and results from the NEXT prototype for Double Beta and Dark Matter (NEXT-DBDM) detector, a high-pressure gaseous natural xenon electroluminescent time projection chamber (TPC) that was built at the Lawrence Berkeley National Laboratory. It is a prototype of the planned NEXT-100 136Xe neutrino-less double beta decay (0νββ) experiment with the main objectives of demonstrating near-intrinsic energy resolution at energies up to 662 keV and of optimizing the NEXT-100 detector design and operating parameters. Energy resolutions of ∼1% FWHM for 662 keV gamma rays were obtained at 10 and 15 atm and ∼5% FWHM for 30 keV fluorescence xenon X-rays. These results demonstrate that 0.5% FWHM resolutions for the 2,459 keV hypothetical neutrino-less double beta decay peak are realizable. This energy resolution is a factor 7 to 20 better than that of the current leading 0νββ experiments using liquid xenon and thus represents a significant advancement. We present also first results from a track imaging system consisting of 64 silicon photo-multipliers recently installed in NEXT-DBDM that, along with the excellent energy resolution, demonstrates the key functionalities required for the NEXT-100 0νββ search

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200

Effects of maternal trauma and associated psychopathology on atypical maternal behavior and infant social withdrawal six months postpartum.

Maternal psychopathology given a history of maltreatment and domestic violence exposure increases the risk for child psychopathology. Infant social withdrawal is one warning sign of adverse developmental outcomes including child anxiety and depression. It remains unclear how maternal trauma-related psychopathology might affect infant social withdrawal six-months postpartum. One-hundred ninety-five women and their six-month-old infants were studied in an at-risk community sample. Maternal trauma history, posttraumatic stress (PTSD) and major depressive (MDD) disorders were assessed. Maternal and infant behaviors were coded from videotaped interactions. Maternal trauma was correlated with atypical maternal behavior (AMB) and infant social withdrawal (p ≤ .001). PTSD and MDD, and comorbid PTSD/MDD predicted increased AMB (p ≤ .001) but only maternal MDD was predictive of infant social withdrawal (p ≤ .001). Effects of maternal MDD on infant withdrawal were mediated by AMB. At six-months postpartum, maternal MDD was associated with infant withdrawal. AMB is an important target for early intervention

Revisiting Botnet Models and Their Implications for Takedown Strategies

Abstract. Several works have utilized network models to study peerto-peer botnets, particularly in evaluating the effectiveness of strategies aimed at taking down a botnet. We observe that previous works fail to consider an important structural characteristic of networks — assortativity. This property quantifies the tendency for “similar ” nodes to connect to each other, where the notion of “similarity ” is examined in terms of node degree. Empirical measurements on networks simulated according to the Waledac botnet protocol, and on network traces of bots from a honeynet running in the wild, suggest that real-world botnets can be significantly assortative, even more so than social networks. By adjusting the level of assortativity in simulated networks, we show that high assortativity allows networks to be more resilient to takedown strategies than predicted by previous works, and can allow a network to “heal ” itself effectively after a fraction of its nodes are removed. We also identify alternative takedown strategies that are more effective, and more difficult for the network to recover from, than those explored in previous works.