Search results for "Speed"
showing 10 items of 876 documents
Precise predictions for Dirac neutrino mixing
2016
The neutrino mixing parameters are thoroughly studied using renormalization-group evolution of Dirac neutrinos with recently proposed parametrization of the neutrino mixing angles referred as `high-scale mixing relations'. The correlations among all neutrino mixing and $CP$ violating observables are investigated. The predictions for the neutrino mixing angle $\theta_{23}$ are precise, and could be easily tested by ongoing and future experiments. We observe that the high scale mixing unification hypothesis is incompatible with Dirac neutrinos due to updated experimental data.
Can we probe intrinsic CP and T violations and nonunitarity at long baseline accelerator experiments?
2017
One of the fundamental parameters entering the neutrino oscillation framework is the leptonic $CP$ phase ${\ensuremath{\delta}}_{13}$, and its measurement is an important goal of the planned long baseline experiments. It should be noted that ordinary matter effects complicate the determination of this parameter, and there are studies in the literature that deal with separation of intrinsic vs extrinsic $CP$ violation. It is important to investigate the consequences of new physics effects that can not only hamper the measurement of ${\ensuremath{\delta}}_{13}$ but also impact the consequences of discrete symmetries such as $CP$, $T$, and unitarity in different oscillation channels. In the pr…
Electroweak baryogenesis at high bubble wall velocities
2020
It is widely believed that electroweak baryogenesis should be suppressed in strong phase transitions with fast-moving bubble walls, but this effect has never been quantitatively studied. We rederive fluid equations describing transport of particle asymmetries near the bubble wall without making the small-wall-velocity approximation. We show that the suppression of the baryon asymmetry is a smooth function of the wall speed and that there is no special behavior when crossing the sound speed barrier. Electroweak baryogenesis can thus be efficient also with strong detonations, generically associated with models with observably large gravitational waves. We also make a systematic and critical c…
The antares neutrino detector instrumentation
2012
ANTARES is actually the fully operational and the largest neutrino telescope in the Northern hemisphere. Located in the Mediterranean Sea, it consists of a 3D array of 885 photomultiplier tubes (PMTs) arranged in 12 detection lines (25 storeys each), able to detect the Cherenkov light induced by upgoing relativistic muons produced in the interaction of high energy cosmic neutrinos with the detector surroundings. Among its physics goals, the search for neutrino astrophysical sources and the indirect detection of dark matter particles coming from the sun are of particular interest. To reach these goals, good accuracy in track reconstruction is mandatory, so several calibration systems for tim…
Supersonic Magnetic Upflows in Granular Cells Observed with Sunrise/IMaX
2010
Using the IMaX instrument on-board the Sunrise stratospheric balloon-telescope we have detected extremely shifted polarization signals around the Fe I 5250.217 {\AA} spectral line within granules in the solar photosphere. We interpret the velocities associated with these events as corresponding to supersonic and magnetic upflows. In addition, they are also related to the appearance of opposite polarities and highly inclined magnetic fields. This suggests that they are produced by the reconnection of emerging magnetic loops through granular upflows. The events occupy an average area of 0.046 arcsec$^2$ and last for about 80 seconds, with larger events having longer lifetimes. These supersoni…
Effects of the Lorentz invariance violation in Coulomb interaction in nuclei and atoms
2016
Anisotropy in the speed of light that has been constrained by Michelson-Morley-type experiments also generates anisotropy in the Coulomb interactions. This anisotropy can manifest itself as an energy anisotropy in nuclear and atomic experiments. Here the experimental limits on Lorentz violation in 21Ne are used to improve the limits on the Lorentz symmetry in the photon sector, namely the anisotropy of the speed of light and the Coulomb interactions, by 7 orders of magnitude in comparison with previous experiments: the speed of light is isotropic to a part in E-28.
Status of the neutrino telescope AMANDA: Monopoles and WIMPs
2001
The neutrino telescope AMANDA has been set up at the geographical South Pole as first step to a neutrino telescope of the scale of one cubic kilometer, which is the canonical size for a detector sensitive to neutrinos from Active Galactic Nuclei (AGN), Gamma Ray Bursts (GRB) and Topological Defects (TD). The location and depth in which the detector is installed is given by the requirement to detect neutrinos by the Cherenkov light produced by their reaction products and to keep the background due to atmospheric muons as small as possible. However, a detector optimized for this purpose is also capable to detect the bright Cherenkov light from relativistic Monopoles and neutrino signals from …
Indirect searches for Dark Matter with the ANTARES neutrino telescope
2012
The results of a search for high-energy neutrinos coming from the direction of the Sun using the data recorded by the ANTARES neutrino telescope during 2007 and 2008 are presented. The number of neutrinos observed is found to be compatible with background expectations and upper limits for the spin-dependent and spin-independent WIMP-proton cross-sections are derived and compared to predictions of the CMSSM. These limits are comparable to those obtained by other neutrino telescopes and are more stringent than those obtained by direct search experiments for the spin-dependent WIMP-proton cross-section assuming the self-annihilation proceeds through hard channels, i.e. via W + W and t + t .
Status of the IceCube Neutrino Observatory
2004
Abstract The IceCube neutrino telescope, to be constructed near the Antarctic South Pole, represents the next generation of neutrino telescope. Its large 1 km3 size will make it uniquely sensitive to the detection of neutrinos from astrophysical sources. The current design of the detector is presented. The basic performance of the detector and its ability to search for neutrinos from various astrophysical sources has been studied using detailed simulations and is discussed.
Quantum Search with Multiple Walk Steps per Oracle Query
2015
We identify a key difference between quantum search by discrete- and continuous-time quantum walks: a discrete-time walk typically performs one walk step per oracle query, whereas a continuous-time walk can effectively perform multiple walk steps per query while only counting query time. As a result, we show that continuous-time quantum walks can outperform their discrete-time counterparts, even though both achieve quadratic speedups over their corresponding classical random walks. To provide greater equity, we allow the discrete-time quantum walk to also take multiple walk steps per oracle query while only counting queries. Then it matches the continuous-time algorithm's runtime, but such …