Search results for "Detectors"
showing 10 items of 2229 documents
Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam
2000
We carried out a model-independent search for light scalar or pseudoscalar particles $a$'s (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to $eV$ masses.\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\ The new particles, if they exist, could be produced through the Primakoff effect in interactions of high energy photons, generated by the 450 $GeV$ protons in the CERN SPS neutrino target, with virtual photons from the WANF horn magnetic field.\ The particles would penetrate the downstre…
Heavy neutrino mixing and single production at linear collider
1997
We study the single production of heavy neutrinos via the processes $e^-e^+ \to \nu N$ and $e^-\gamma \to W^- N$ at future linear colliders. As a base of our considerations we take a wide class of models, both with vanishing and non-vanishing left-handed Majorana neutrino mass matrix $m_L$. We perform a model independent analyses of the existing experimental data and find connections between the characteristic of heavy neutrinos (masses, mixings, CP eigenvalues) and the $m_L$ parameters. We show that with the present experimental constraints heavy neutrino masses almost up to the collision energy can be tested in the future experiments.
Light vector mediators facing XENON1T data
2020
Recently the XENON1T collaboration has released new results on searches for new physics in low-energy electronic recoils. The data shows an excess over background in the low-energy tail, particularly pronounced at about $2-3$ keV. With an exposure of $0.65$ tonne-year, large detection efficiency and energy resolution, the detector is sensitive as well to solar neutrino backgrounds, with the most prominent contribution given by $pp$ neutrinos. We investigate whether such signal can be explained in terms of new neutrino interactions with leptons mediated by a light vector particle. We find that the excess is consistent with this interpretation for vector masses below $\lesssim 0.1$ MeV. The r…
Solar neutrinos as probes of neutrino–matter interactions
2004
Data from solar neutrino and KamLAND experiments have led to a discovery of nonzero neutrino masses. Here we investigate what these data can tell us about neutrino interactions with matter, including the poorly constrained flavor-changing nu_e-nu_tau interactions. We give examples of the interaction parameters that are excluded by the solar/KamLAND data and are beyond the reach of other experiments. We also demonstrate that flavor-changing interactions, at the allowed level, may profoundly modify the conversion probability for neutrinos of energy <~ 6 MeV and the values of the mass parameter inferred from the data. The implications for future experiments are discussed.
Evaluation of the local hadronic calibration with combined beam-test data for the endcap and forward calorimeters of ATLAS in the pseudorapidity regi…
2012
Abstract The local hadronic calibration scheme developed for the reconstruction and calibration of jets and missing transverse energy in ATLAS has been evaluated using data obtained during combined beam tests of modules of the ATLAS liquid argon endcap and forward calorimeters. These tests covered the pseudorapidity range of 2.5 | η | 4.0 . The analysis has been performed using special sets of calibration weights and corrections obtained with the G eant 4 simulation of a detailed beam-test setup. The evaluation itself has been performed through the careful study of specific calorimeter performance parameters such as e.g. energy response and resolution, shower shapes, as well as different ph…
Neutrino properties
1996
A brief sketch is made of the present observational status of neutrino properties, with emphasis on the hints from solar and atmospheric neutrinos, as well as cosmological data on the amplitude of primordial density fluctuations. Implications of neutrino mass in particle accelerators, astrophysics and cosmology are discussed.
An improved cosmological bound on the tau-neutrino mass
1996
We consider the influence of non-equilibrium electronic neutrinos (and anti-neutrinos) on the neutron-to-proton ratio. These neutrinos would come from massive $\nu_\tau$ annihilations $\bar \nu_\tau \nu_\tau \rightarrow \bar \nu_e \nu_e$. For sufficiently large $\nu_\tau$ masses this new effect would strongly enhance the (n/p)-ratio, leading to a very stringent bound on the $\nu_\tau$ mass, even adopting a rather weak upper bound on the effective number on neutrino species during nucleosynthesis.
The AMANDA neutrino detector - Status report
2000
Abstract The first stage of the AMANDA High Energy Neutrino Detector at the south Pole, the 302 PMT array AMANDA-B10, is taking data since 1997. We describe results on atmospheric neutrinos, limits on indirect WIMP detection, seasonal muon flux variation, relativistic monopole flux limits, a search for gravitational collapse neutrinos, and a depth scan of the optical ice properties. The next stage 19-string detector AMANDA-II with ∼650 PMTs will be completed in spring 2000.
17 keV neutrino in a singlet-triplet majoron model
1991
Abstract We investigate the possibility of a cosmologically safe 17 keV neutrino which may have been observed in the decays of tritium, S 35 , and C 14 within a singlet-triplet majoron model. Consideration of the leptonic decay of K + and X rays associated with the radiative decay of massive relic neutrinos severely constrains the scale of the spontaneous lepton number violation. It is argued that the mass density of relic 17 keV neutrinos is constrained as Ω v ⩽ 0.05 h −1 (0.01/ sin 2 θ ) in view of the observed diffuse X ray background.
Mass of tau neutrino in SO(10) GUT-s
1997
We investigate the allowed ranges of masses for an unstable tau neutrino in the context of SO(10) GUT-s. In light of the new nucleosynthesis results we obtain that there is a narrow window for m_{\nu_\tau} where the LEP, neutrino oscillation and nucleosynthesis data are compatible. This window, which depends on the effective number of neutrinos contributing to nucleosynthesis, has important cosmological consequences and will be tested by ongoing neutrino oscillation and LEP II experiments.