16,507 research outputs found
Search for Heavy Right-Handed Neutrinos at the LHC and Beyond in the Same-Sign Same-Flavor Leptons Final State
In this study we explore the LHC's Run II potential to the discovery of heavy
Majorana neutrinos, with luminosities between and fb in the
final state. Given that there exist many models for
neutrino mass generation, even within the Type I seesaw framework, we use a
simplified model approach and study two simple extensions to the Standard
Model, one with a single heavy Majorana neutrino, singlet under the Standard
Model gauge group, and a limiting case of the left-right symmetric model. We
then extend the analysis to a future hadron collider running at TeV
center of mass energies. This extrapolation in energy allows us to study the
relative importance of the resonant production versus gauge boson fusion
processes in the study of Majorana neutrinos at hadron colliders. We analyze
and propose different search strategies designed to maximize the discovery
potential in either the resonant production or the gauge boson fusion modes
PARISROC, a Photomultiplier Array Integrated Read Out Chip
PARISROC is a complete read out chip, in AMS SiGe 0.35 !m technology, for
photomultipliers array. It allows triggerless acquisition for next generation
neutrino experiments and it belongs to an R&D program funded by the French
national agency for research (ANR) called PMm2: ?Innovative electronics for
photodetectors array used in High Energy Physics and Astroparticles?
(ref.ANR-06-BLAN-0186). The ASIC (Application Specific Integrated Circuit)
integrates 16 independent and auto triggered channels with variable gain and
provides charge and time measurement by a Wilkinson ADC (Analog to Digital
Converter) and a 24-bit Counter. The charge measurement should be performed
from 1 up to 300 photo- electrons (p.e.) with a good linearity. The time
measurement allowed to a coarse time with a 24-bit counter at 10 MHz and a fine
time on a 100ns ramp to achieve a resolution of 1 ns. The ASIC sends out only
the relevant data through network cables to the central data storage. This
paper describes the front-end electronics ASIC called PARISROC.Comment: IEEE Nuclear Science Symposium an Medical Imaging Conference (2009
NSS/MIC
Stochastic Liouville equation simulation of multidimensional vibrational line shapes of trialanine
The line shapes detected in coherent femtosecond vibrational spectroscopies contain direct signatures of peptide conformational fluctuations through their effect on vibrational frequencies and intermode couplings. These effects are simulated in trialanine using a Green's function solution of a stochastic Liouville equation constructed for four collective bath coordinates (two Ramachandran angles affecting the mode couplings and two diagonal energies). We find that fluctuations of the Ramachandran angles which hardly affect the linear absorption can be effectively probed by two-dimensional spectra. The signal generated at k(1)+k(2)-k(3) is particularly sensitive to such fluctuations. (C) 2004 American Institute of Physics
Structure preserving primal dual methods for gradient flows with nonlinear mobility transport distances
We develop structure preserving schemes for a class of nonlinear mobility continuity equation.
When the mobility is a concave function, this equation admits a form of gradient flow with respect
to a Wasserstein-like transport metric. Our numerical schemes build upon such formulation and utilize modern large scale optimization algorithms. There are two distinctive features of our approach
compared to previous ones. On one hand, the essential properties of the solution, including positivity, global bounds, mass conservation and energy dissipation are all guaranteed by construction. On
the other hand, it enjoys sufficient flexibility when applies to a large variety of problems including
different free energy functionals, general wetting boundary conditions and degenerate mobilities.
The performance of our methods are demonstrated through a suite of examples
Chemical-free inactivated whole influenza virus vaccine prepared by ultrashort pulsed laser treatment
There is an urgent need for rapid methods to develop vaccines in response to emerging viral pathogens. Whole inactivated virus (WIV) vaccines represent an ideal strategy for this purpose; however, a universal method for producing safe and immunogenic inactivated vaccines is lacking. Conventional pathogen inactivation methods such as formalin, heat, ultraviolet light, and gamma rays cause structural alterations in vaccines that lead to reduced neutralizing antibody specificity, and in some cases, disastrous T helper type 2-mediated immune pathology. We have evaluated the potential of a visible ultrashort pulsed (USP) laser method to generate safe and immunogenic WIV vaccines without adjuvants. Specifically, we demonstrate that vaccination of mice with laser-inactivated H1N1 influenza virus at about a 10-fold lower dose than that required using conventional formalin-inactivated influenza vaccines results in protection against lethal H1N1 challenge in mice. The virus, inactivated by the USP laser irradiation, has been shown to retain its surface protein structure through hemagglutination assay. Unlike conventional inactivation methods, laser treatment did not generate carbonyl groups in protein, thereby reducing the risk of adverse vaccine-elicited T helper type 2 responses. Therefore, USP laser treatment is an attractive potential strategy to generate WIV vaccines with greater potency and safety than vaccines produced by current inactivation techniques
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