123338648
New Opportunities for Surprise
If history is any guide, then there is a good chance that our present description of neutrinos is wrong. Over the past 30 years, neutrino physics has again and again produced results which took us by surprise, and forced us to change our theoretical direction. In light of this, it is worth examining the experimental clues we now have to see if they lead to ideas outside our "New Standard Model." Our present paradigm says that there are only three neutrinos participating in the weak interaction. They are light, with masses less than 0.1 eV, and predicted to be Majorana neutrinos, that is, each is its own antiparticle. The light mass is motivated by the see-saw model, which postulates partners which are very massive (~hundreds of GeV). By contrast with this "conventional wisdom," this talk discusses five examples of experimental results which, if confirmed, would cause us to rethink our theory. It focuses only on oscillations, and on those questions which can be addressed at accelerators. Other ways neutrinos may be surprising, such as the anomalous measurement of sin2θW from NuTeV, are left for other talks. The ideas discussed here are best explored through accelerator-produced neutrino beams. So the reasons why beam-based experiments are becoming the venue-of-choice are then examined. Lastly, the first two of the five ideas are explored in detail.
118381753
A Study of the Fluorescence Response of Tetraphenyl-butadiene
Tetraphenyl-butadiene (TPB) is a widely used fluorescent wavelength-shifter. A common application is in liquid-argon-based particle detectors, where scintillation light is produced in the UV at 128 nm. In liquid argon experiments, TPB is often employed to shift the scintillation light to the visible range in order to allow detection via standard photomultiplier tubes. This paper presents studies on the stability of TPB with time under exposure to light. We also examine batch-to-batch variations. We compare scintillation-grade TPB to 99% pure TPB response. In the 99% pure samples, we report a yellowing effect, and full degradation of the TPB emission-peak, upon extended exposure to light.
119757503
A review of experimental results on neutrino oscillations
208856461
Search for core-collapse supernovae using the MiniBooNE neutrino detector
We present a search for core-collapse supernovae in the Milky Way galaxy, using the MiniBooNE neutrino detector. No evidence is found for core-collapse supernovae occurring in our Galaxy in the period from December 14, 2004 to July 31, 2008, corresponding to 98% live time for collection. We set a limit on the core-collapse supernova rate out to a distance of 13.4 kpc to be less than 0.69 supernovae per year at 90% C.L.
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.
118385577
Measurements of the rates of forward jet production in deep inelastic muon scattering
15092137
Detecting Dark Matter annihilation lines with Fermi
Dark matter constitutes one of the most intriguing but so far unresolved issues in physics today. In many extensions of the Standard Model the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an excellent dark matter particle candidate and one of the most interesting scenarios include an annihilation of two WIMPs into two gamma-rays. If the WIMPs are assumed to be non-relativistic, the resulting photons will both have an energy equal to the mass of the WIMP and manifest themselves as a monochromatic spectral line in the energy spectrum. This type of signal would represent a 'smoking gun' for dark matter, since no other known astrophysical process should be able to produce it. In these proceedings we give an overview of the different approaches to a search for dark matter lines that the Fermi-LAT collaboration is pursuing and the various challenges involved.
15358736
Search for neutrino-induced cascades with the AMANDA detector
J. Ahrens, X. Bai, G. Barouch, S.W. Barwick, R.C. Bay, T. Becka, K.-H. Becker, D. Bertrand, F. Binon, A. Biron, S. Böser, J. Booth, O. Botner, A. Bouchta, a O. Bouhali, M.M. Boyce, T. Burgess, S. Carius, A. Chen, D. Chirkin, J. Conrad, J. Cooley, C.G.S. Costa, D.F. Cowen, A. Davour, C. De Clercq, T. DeYoung, b P. Desiati, J.-P. Dewulf, P. Doksus, P. Ekström, T. Feser, J.-M. Frère, T.K. Gaisser, M. Gaug, A. Goldschmidt, A. Hallgren, F. Halzen, K. Hanson, R. Hardtke, T. Hauschildt, M. Hellwig, G.C. Hill, P.O. Hulth, K. Hultqvist, S. Hundertmark, J. Jacobsen, A. Karle, J. Kim, B. Koci, L. Köpke, M. Kowalski, J.I. Lamoureux, H. Leich, M. Leuthold, P. Lindahl, I. Liubarsky, D.M. Lowder, c J. Madsen, P. Marciniewski, H.S. Matis, C.P. McParland, T.C. Miller, d Y. Minaeva, P. Miočinović, P.C. Mock, e R. Morse, T. Neunhöffer, P. Niessen, D.R. Nygren, H. Ogelman, Ph. Olbrechts, C. Pérez de los Heros, A.C. Pohl, R. Porrata, f P.B. Price, G.T. Przybylski, K. Rawlins, C. Reed, g E. Resconi, W. Rhode, M. Ribordy, S. Richter, J. Rodŕıguez Martino, P. Romenesko, D. Ross, H.-G. Sander, T. Schmidt, D. Schneider, R. Schwarz, A. Silvestri, M. Solarz, G.M. Spiczak, C. Spiering, N. Starinsky, h D. Steele, P. Steffen, R.G. Stokstad, K.-H. Sulanke, I. Taboada, i L. Thollander, S. Tilav, M. Vander Donckt, C. Walck, C. Weinheimer, C.H. Wiebusch, a C. Widemann, R. Wischnewski, H. Wissing, K. Woschnagg, W. Wu, G. Yodh, and S. Young
118237340
Response of AMANDA-II to Cosmic Ray Muons
The high flux of down-going muon detected by the AMANDA-II neutrino telescope is used as a test beam to check the experiment systematics and to improve the knowledge of its response. This work shows the result of the effort to get a better understanding of AMANDA-II performance, an improved data filter and event reconstruction. The preliminary experimental down-going muon angular and depth intensities are compared with Monte Carlo prediction, other experimental results and theoretical calculations. A good agreement is found within systematic uncertainties.
53326002
Muon Track Reconstruction and Data Selection Techniques in AMANDA
The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice between 1500 and 2000 m. The primary goal of this detector is to discover astrophysical sources of high-energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector. The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2° accuracy. © 2004 Elsevier B.V. All rights reserved.
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.