17385602
On sensitivity calculations for neutrino oscillation experiments
Calculations of sensitivities of future experiments are a necessary ingredient in experimental high energy physics. Especially in the context of measurements of the neutrino oscillation parameters extensive studies are performed to arrive at the optimal configuration. In this note we clarify the definition of sensitivity as often applied in these studies. In addition, we examine two of the most common methods to calculate sensitivity from a statistical perspective using a toy model. The importance of inclusion of uncertainties in nuisance parameters for the interpretation of sensitivity calculations is pointed out.
120082547
Fermi Gamma-ray Space Telescope sees first light
With exceptional resolution and sensitivity, the latest orbiting gamma-ray telescope based on detection techniques from particle physics is opening a new window on the high-energy universe.
18437847
Fluctuation studies and energy reconstruction in a segmented calorimeter
In order to better understand energy estimation of electromagnetic showers in segmented calorimeters, detailed Geant4 simulation studies of electromagnetic showers in the energy range 1-100 GeV in CsI have been performed. When sampled in layers of 1.99 cm thickness, corresponding to 1.08 radiation lengths, the energy fluctuations in the samples show distributions that vary significantly with depth. The energy distributions are similar for incident electrons and photons and were found to change systematically along the shower, varying little with the initial energy. Three probability distributions have been fitted to the data: negative binomial, log-normal and Gaussian distributions, none of which gives a good fit over the full shower length. The obtained parameterizations might be useful in the use of the maximum likelihood method for estimating the energy. Two methods for estimating the energy have also been studied. One method is based on fitting individual longitudinal shower profiles with a Gamma-function, the other one corrects the measured energy for leakage by utilizing the energy deposited in the last layer. Our simulations indicate that the last-layer correction method applied to photons and electrons of 1 and 10 GeV gives about a factor of 2 improvement in the energy resolution.
118846253
Future dark matter searches with the GLAST-LAT
The Large Area Telescope, one of two instruments on the Gamma-ray Large Area Space Telescope mission, scheduled for launch by NASA in early 2008, is a high-energy gamma-ray telescope, sensitive to an energy range from approximately 20 MeV to more than 300 GeV and exceeding the sensitivity of its predecessor EGRET by nearly two orders of magnitude. Annihilation of Weakly Interacting Massive Particles (WIMP), predicted in many extensions of the Standard Model of Particle Physics, may give rise to a signal in gamma-ray spectra from many cosmic sources. In this contribution we give an overview of the searches for WIMP Dark Matter performed by the GLAST-LAT collaboration, in particular we discuss the sensitivity of GLAST to thermal WIMP dark matter in the galactic center and to high energy (50 -150 GeV) gamma-ray lines resulting from WIMP pair annihilation into two gamma-rays.
118516643
Anisotropies in the diffuse gamma-ray background from dark matter with Fermi LAT: a closer look
This thesis addresses the isotropic diffuse gamma-ray background, as measured by the Fermi gamma ray space telescope, and its implications for indirect detection of dark matter. We describe the measurement of the isotropic background, including also an alternative analysis method besides the one published by the Fermi-LAT collaboration. The measured isotropic diffuse background is compatible with a power law differential energy spectrum with a spectral index of -2.41 ± 0.05 and -2.39 ± 0.08, for the two analysis methods respectively. This is a softer spectrum than previously reported by the EGRET experiment. This rules out any dominant contribution with a significantly different shape, e.g. from dark matter, in the energy range 20 MeV to 102.4 GeV. Instead we present upper limits on a signal originating from annihilating dark matter of extragalactic origin. The uncertainty in the dark matter signal is primarily dependent on the cosmological evolution of the dark matter distribution. We use recent N-body simulations of structure formation, as well as a semi-analytical calculation, to assess this uncertainty. We investigate three main annihilation channels and find that in some, but not in all, of our scenarios we can start to probe, and sometimes rule out, interesting parameter spaces of particle physics models beyond the standard model.We also investigate the possibility to use the angular anisotropies of the annihilation signal to separate it from a background originating from conventional sources, e.g. from active galactic nuclei. By carefully modelling the performance of the Fermi gamma-ray space telescope and galactic foregrounds we find that this method could be as sensitive as using information from the energy spectrum only.
15402465
Coverage of Confidence Intervals for Poisson Statistics in Presence of Systematic Uncertainties
Coverage of Confidence Intervals for Poisson Statistics in Presence of Systematic Uncertainties
13999234
Recent Results on Neutrino Oscillations
This article reviews the many new results from neutrino oscillation searches which were presented at ICHEP '98. Exciting indications of neutrino oscillations have been seen in the solar neutrino deficit, atmospheric neutrino deficit and LSND excess. These indications and reported limits on oscillations are considered. Attempts to develop a theory which addresses all of the neutrino oscillation data are discussed. Some of the remaining questions and the future experiments which will help answer these questions are described.
122729879
Bringing the SciBar detector to the booster neutrino beam
This document presents the physics case for bringing SciBar, the fully active, finely segmented tracking detector at KEK, to the FNAL Booster Neutrino Beam (BNB) line. This unique opportunity arose with the termination of K2K beam operations in 2005. At that time, the SciBar detector became available for use in other neutrino beam lines, including the BNB, which has been providing neutrinos to the MiniBooNE experiment since late 2002. The physics that can be done with SciBar/BNB can be put into three categories, each involving several measurements. First are neutrino cross section measurements which are interesting in their own right, including analyses of multi-particle final states, with unprecedented statistics. Second are measurements of processes that represent the signal and primary background channels for the upcoming T2K experiment. Third are measurements which improve existing or planned MiniBooNE analyses and the understanding of the BNB, both in neutrino and antineutrino mode. For each of these proposed measurements, the SciBar/BNB combination presents a unique opportunity or will significantly improve upon current or near-future experiments for several reasons. First, the fine granularity of SciBar allows detailed reconstruction of final states not possible with the MiniBooNE detector. Additionally, the BNB neutrino energy spectrum is amore » close match to the expected T2K energy spectrum in a region where cross sections are expected to vary dramatically with energy. As a result, the SciBar/BNB combination will provide cross-section measurements in an energy range complementary to MINERvA and complete the knowledge of neutrino cross sections over the entire energy range of interest to the upcoming off-axis experiments.« less
5993897
Neutrino Scattering on Glass: NuSOnG
These proceedings describe the physics goals and initial design for a new experiment: NuSOnG—Neutrino Scattering On Glass. The design will yield about two orders of magnitude higher statistics than previous high energy neutrino experiments, observed in a detector optimized for low hadronic energy and electromagnetic events. As a result, the purely weak processes νμ+e−→νμ+e− and νμ+e−→νe+μ− (inverse muon decay) can be measured with high accuracy for the first time. This allows important precision electroweak tests and well as direct searches for new physics. The high statistics also will yield the world's largest sample of Deep Inelastic (DIS) events for precision parton distribution studies.
56440520
Supernova neutrinos and the LSND evidence for neutrino oscillations
The observation of the $\bar{\nu}_e$ energy spectrum from a supernova burst can provide constraints on neutrino oscillations. We derive formulas for adiabatic oscillations of supernova antineutrinos for a variety of 3- and 4-neutrino mixing schemes and mass hierarchies which are consistent with the LSND evidence for $\bar{\nu}_{\mu}\to \bar{\nu}_e$ oscillations. 
Finally, we explore the constraints on these models and LSND given by the supernova SN1987A $\bar{\nu}_e$'s observed by the Kamiokande-2 and IMB-3 detectors.
14263651
SIMULATIONS OF PION PRODUCTION IN THE DAEDALUS TARGET
DAEDALUS, the Decay At-rest Experiment for DCP at a 
Laboratory for Underground Science will look for evidence 
of CP-violation in the neutrino sector, an ingredient in theories 
that seek to explain the matter/antimatter asymmetry 
in our universe. It will make a precision measurement of 
the oscillations of muon antineutrinos to electron antineutrinos 
using multiple neutrino sources created by low-cost 
compact cyclotrons. The experiment utilizes decay-at-rest 
neutrino beams produced by 800 MeV protons impinging 
a beam target of graphite and copper. Two well established 
Monte Carlo codes, MARS and GEANT4, have been used 
to optimise the design and the performance of the target. A 
study of the results obtained with these two codes is presented 
in this paper.