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On the Detection of the Free Neutrino

Description: The experiment previously proposed [to Detect the Free Neutrino] has been initiated, with a Hanford pile as a neutrino source. It appears probable that neutrino detection has been accomplished, and confirmatory work is in progress. (K.S.)
Date: August 1, 1953
Creator: Reines, F. & Cowan, C. L., Jr.
Partner: UNT Libraries Government Documents Department

MSW Effects in Vacuum Oscillations

Description: We point out that for solar neutrino oscillations with the mass-squared difference of Delta m^2 ~;; 10^-10 - 10^-9 eV^2, traditionally known as"vacuum oscillation'' range, the solar matter effects are non-negligible, particularly for the low energy pp neutrinos. One consequence of this is that the values of the mixing angle theta and pi/2-theta are not equivalent, leading to the need to consider the entire physical range of the mixing angle 0<=theta<=pi/2 when determining the allowed values of the neutrino oscillation parameters.
Date: February 6, 2000
Creator: Friedland, Alexander
Partner: UNT Libraries Government Documents Department

How Can We Test Seesaw Experimentally?

Description: The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve a variety of data from LHC, ILC, cosmology, underground, and low-energy flavor violation experiments to establish the case.
Date: June 7, 2006
Creator: Buckley, Matthew R. & Murayama, Hitoshi
Partner: UNT Libraries Government Documents Department

Anarchy and hierarchy

Description: We advocate a new approach to study models of fermion massesand mixings, namely anarchy proposed in hep-ph/9911341. In this approach,we scan the O(1) coefficients randomly. We argue that this is the correctapproach when the fundamental theory is sufficiently complicated.Assuming there is no physical distinction among three generations ofneutrinos, the probability distributions in MNS mixing angles can bepredicted independent of the choice of the measure. This is because themixing angles are distributed according to the Haar measure of the Liegroups whose elements diagonalize the mass matrices. The near-maximalmixings, as observed in the atmospheric neutrino data and as required inthe LMA solution to the solar neutrino problem, are highly probable. Asmall hierarchy between the Delta m2 for the atmospheric and the solarneutrinos is obtained very easily; the complex seesaw case gives ahierarchy of a factor of 20 as the most probable one, even though thisconclusion is more measure-dependent. U_e3 has to be just below thecurrent limit from the CHOOZ experiment. The CP-violating parameter sindelta is preferred to be maximal. We present a simple SU(5)-likeextension of anarchy to the charged-lepton and quark sectors which workswell phenomenologically.
Date: September 14, 2000
Creator: Haba, Naoyuki & Murayama, Hitoshi
Partner: UNT Libraries Government Documents Department

Baryon Triality And Neutrino Masses From An Anomalous FlavorU(1)

Description: We construct a concise U(1){sub X} Froggatt-Nielsen model in which baryon triality, a discrete gauge Z{sub 3}-symmetry, arises from U(1){sub X} breaking. The proton is thus stable, however, R-parity is violated. With the proper choice of U(1){sub X} charges we can obtain neutrino masses and mixings consistent with an explanation of the atmospheric and solar neutrino anomalies in terms of neutrino oscillations, with no right-handed neutrinos required. The only mass scale apart from M{sub grav} is m{sub soft}.
Date: August 15, 2007
Creator: Dreiner, Herbi K.; Luhn, Christoph; Murayama, Hitoshi & Thormeier,Marc
Partner: UNT Libraries Government Documents Department

LSND, SN1987A, and CPT violation

Description: We point out that neutrino events observed at Kamiokande andIMB from SN1987A disfavor the neutrino oscillation parameters preferredby the LSND experiment. For Delta m2>0 (the light side), theelectron neutrinos from the neutronization burst would be lost, while thefirst event at Kamiokande is quite likely to be due to an electronneutrino. For Delta m2<0 (the dark side), the average energy of thedominantly bar nu e events is already lower than the theoreticalexpectations, which would get aggravated by a complete conversion frombar nu mu to bar nu e. If taken seriously, the LSND data are disfavoredindependent of the existence of a sterile neutrino. A possible remedy isCPT violation, which allows different mass spectra for neutrinos andanti-neutrinos and hence can accommodate atmospheric, solar and LSND datawithout a sterile neutrino. If this is the case, Mini-BooNE must run inbar nu rather than the planned nu mode to test the LSND signal. Wespeculate on a possible origin of CPT violation.
Date: October 17, 2000
Creator: Murayama, Hitoshi & Yanagida, T.
Partner: UNT Libraries Government Documents Department


Description: We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-08 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of livetime. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 {sigma} after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E{sup -2} spectrum is E{sup 2} {Phi}{sub {nu}{sub {mu}}} &lt; 1.4 x 10{sup -1} TeV cm{sup -2}s{sup -1}, in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of two.
Date: May 14, 2009
Creator: Collaboration, IceCube & Klein, Spencer
Partner: UNT Libraries Government Documents Department

Multi-year search for a diffuse flxu of muon neutrinos with AMANDA-II

Description: A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent livetime of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with non-thermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E{sup 2}{Phi}{sub 90%C.L.} &lt; 7.4 x 10{sup -8} GeV cm{sup -2} s{sup -1} sr{sup -1} is placed on the diffuse flux of muon neutrinos with a {Phi} {proportional_to} E{sup -2} spectrum in the energy range 16 TeV to 2.5 PeV. This is currently the most sensitive {Phi} {proportional_to} E{sup -2} diffuse astrophysical neutrino limit. We also set upper limits for astrophysical and prompt neutrino models, all of which have spectra different than {Phi} {proportional_to} E{sup -2}.
Date: April 13, 2008
Creator: Collaboration, IceCube; Klein, Spencer; Achterberg, A. & Collaboration, IceCube
Partner: UNT Libraries Government Documents Department

Search for high-energy muon neutrinos from the"naked-eye" GRB080319B with the IceCube neutrino telescope

Description: We report on a search with the IceCube detector for high-energy muon neutrinos from GRB080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.12 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, there was no excess found above the background. The 90% C.L. upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.0 x 10{sup -3} erg cm{sup -2} in the energy range between 145 TeV and 2.1 PeV, which contains 90% of the expected events.
Date: February 1, 2009
Creator: Collaboration, IceCube & Abbasi, R.
Partner: UNT Libraries Government Documents Department

Neutrino Physics with the IceCube Detector

Description: IceCube is a cubic kilometer neutrino telescope under construction at the South Pole.The primary goal is to discover astrophysical sources of high energy neutrinos.We describe the detector and present results on atmospheric muon neutrinos from2006 data collected with nine detector strings.
Date: June 11, 2008
Creator: Collaboration, IceCube; Kiryluk, Joanna & Kiryluk, Joanna
Partner: UNT Libraries Government Documents Department

Bayesian analysis of the solar neutrino anomaly

Description: We present an analysis of the recent solar neutrino data from the five experiments using Bayesian approach. We extract quantitative and easily understandable information pertaining to the solar neutrino problem. The probability distributions for the individual neutrino fluxes and, discrepancy distribution for B and Be fluxes, which include theoretical and experimental uncertainties have been extracted. The analysis carried out assuming that the neutrinos are unaltered during their passage from the sun to earth, clearly indicate that the observed PP flux is consistent with the 1995 standard solar model predictions of Bahcall and Pinsonneault within 2{sigma} (standard deviation), whereas the {sup 8}B flux is down by more than 12{sigma} and the {sup 7}Be flux is maximally suppressed. We also deduce the experimental survival probability for the solar neutrinos as a function of their energy in a model-independent way. We find that the shape of that distribution is in qualitative agreement with the MSW oscillation predictions.
Date: February 1, 1998
Creator: Bhat, C.M.
Partner: UNT Libraries Government Documents Department

MiniBooNE oscillation searches

Description: The range of oscillation analyses being pursued by the MiniBooNE collaboration is described. Focus is given to the various searches for electron neutrino appearance, but the disappearance of muon neutrinos and the appearance search for electron anti-neutrinos are covered as well.
Date: January 1, 2008
Creator: Brice, Stephen J.
Partner: UNT Libraries Government Documents Department

A p-Adic Metric for Particle Mass Scale Organization with Genetic Divisors

Description: The concept of genetic divisors can be given a quantitative measure with a non-Archimedean p-adic metric that is both computationally convenient and physically motivated. For two particles possessing distinct mass parameters x and y, the metric distance D(x, y) is expressed on the field of rational numbers Q as the inverse of the greatest common divisor [gcd (x , y)]. As a measure of genetic similarity, this metric can be applied to (1) the mass numbers of particle states and (2) the corresponding subgroup orders of these systems. The use of the Bezout identity in the form of a congruence for the expression of the gcd (x , y) corresponding to the v{sub e} and {sub {mu}} neutrinos (a) connects the genetic divisor concept to the cosmic seesaw congruence, (b) provides support for the {delta}-conjecture concerning the subgroup structure of particle states, and (c) quantitatively strengthens the interlocking relationships joining the values of the prospectively derived (i) electron neutrino (v{sub e}) mass (0.808 meV), (ii) muon neutrino (v{sub {mu}}) mass (27.68 meV), and (iii) unified strong-electroweak coupling constant ({alpha}*{sup -1} = 34.26).
Date: December 1, 2001
Partner: UNT Libraries Government Documents Department

Detector R&amp;D for future neutrino experiments with the NuMI beamline.

Description: This document is the result of a request from the Fermilab directorate to (i) investigate the detector technology issues relevant for future long baseline experiments and (ii) consider the associated detector R and D that would be needed to prepare the way for future neutrino oscillation experiments using the NuMI beamline. Because of the narrow energy spread provided by an off-axis beam and the resulting low intrinsic electron neutrino background, as well as the very favorable duty cycle of the NuMI beamline, a well-placed neutrino detector at the surface of the earth could take the next important steps in neutrino oscillation physics. The biggest outstanding issue in this field is whether or not the last unmeasured element of the leptonic mixing matrix, parameterized by the mixing angle {theta}{sub 13}, is nonzero. If it is in fact non-zero, this opens the door to measurements of the neutrino mass hierarchy and, if the solar neutrino oscillations are described by the LMA solution, searches for CP violation in the lepton sector. In order to get to any of these measurements, an off-axis detector must be capable of measuring the {nu}{sub {mu}}({bar {nu}}{sub {mu}}) {yields} {nu}{sub e}({bar {nu}}{sub e}) transition probabilities as well as the {nu}{sub {mu}}({bar {nu}}{sub {mu}}) survival probabilities, at the energies present in these off-axis beams, which could lie anywhere from 0.6 to 3 GeV. Optimal baselines and energies will depend on the physics goal of the experiment. For example, an optimization of the sensitivity for {nu}{sub e} appearance from a {nu}{sub {mu}} beam assuming {Delta}m{sub 32}{sup 2} = 3 x 10{sup -3} eV{sup 2} would lead to a baseline of {approx} 700-900 km and an energy of {approx} 2.2 GeV.
Date: July 25, 2003
Creator: Drake, G.; Goodman, M.; Bareboim, G.; Bodek, A.; Bross, A.; Buckley-Geer, L. et al.
Partner: UNT Libraries Government Documents Department


Description: The physics motivations, design, and status of the Booster Neutrino Experiment at Fermilab, MiniBooNE, are briefly discussed. Particular emphasis is given on the ongoing preparatory work that is needed for the MiniBooNE muon neutrino to electron neutrino oscillation appearance search. This search aims to confirm or refute in a definitive and independent way the evidence for neutrino oscillations reported by the LSND experiment.
Date: February 1, 2006
Creator: Sorel, Michel & U., /Columbia
Partner: UNT Libraries Government Documents Department

Determining neutrino mass hierarchy by precision measurements in electron and muon neutrino disappearance experiments

Description: Recently a new method for determining the neutrino mass hierarchy by comparing the effective values of the atmospheric {Delta}m{sup 2} measured in the electron neutrino disappearance channel, {Delta}m{sup 2}(ee), with the one measured in the muon neutrino disappearance channel, {Delta}m{sup 2}({mu}{mu}), was proposed. If {Delta}m{sup 2}(ee) is larger (smaller) than {Delta}m{sup 2} ({mu}{mu}) the hierarchy is of the normal (inverted) type. We re-examine this proposition in the light of two very high precision measurements: {Delta}m{sup 2}({mu}{mu}) that may be accomplished by the phase II of the Tokai-to-Kamioka (T2K) experiment, for example, and {Delta}m{sup 2}(ee) that can be envisaged using the novel Moessbauer enhanced resonant {bar {nu}}{sub e} absorption technique. Under optimistic assumptions for the systematic uncertainties of both measurements, we estimate the parameter region of ({theta}{sub 13}, {delta}) in which the mass hierarchy can be determined. If {theta}{sub 13} is relatively large, sin{sup 2} 2{theta}{sub 13} {approx}&gt; 0.05, and both of {Delta}m{sup 2}(ee) and {Delta}m{sup 2}({mu}{mu}) can be measured with the precision of {approx} 0.5 % it is possible to determine the neutrino mass hierarchy at &gt; 95% CL for 0.3{pi} {approx}&lt; {delta} {approx}&lt; 1.7 {pi} for the current best fit values of all the other oscillation parameters.
Date: July 1, 2006
Creator: Minakata, H.; U., /Tokyo Metropolitan; Nunokawa, H.; /Rio de Janeiro, Pont. U. Catol.; Parke, S.J.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Measurement of electron neutrino appearance with the MINOS experiment

Description: MINOS is a long-baseline two-detector neutrino oscillation experiment that uses a high intensity muon neutrino beam to investigate the phenomena of neutrino oscillations. By measuring the neutrino interactions in a detector near the neutrino source and again 735 km away from the production site, it is possible to probe the parameters governing neutrino oscillation. The majority of the {nu}{sub {mu}} oscillate to {nu}{sub {tau}} but a small fraction may oscillate instead to {nu}{sub e}. This thesis presents a measurement of the {nu}{sub e} appearance rate in the MINOS far detector using the first two years of exposure. Methods for constraining the far detector backgrounds using the near detector measurements is discussed and a technique for estimating the uncertainty on the background and signal selection are developed. A 1.6{sigma} excess over the expected background rate is found providing a hint of {nu}{sub e} appearance.
Date: May 1, 2009
Creator: Boehm, Joshua Adam Alpern & U., /Harvard
Partner: UNT Libraries Government Documents Department

The Energy Spectrum of Atmospheric Neutrinos between 2 and 200 TeV with the AMANDA-II Detector

Description: The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2-200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed.
Date: May 11, 2010
Creator: Collaboration, IceCube & Abbasi, R.
Partner: UNT Libraries Government Documents Department

Neutrino masses and solar neutrinos

Description: It has been pointed out by Bahcall and Bethe and others that all solar neutrino data can be explained by MSW oscillations with m({nu}{sub {mu}}) {approximately} 10{sup {minus}3} eV consistent with ideas grand unified theories (GUTS). There is a second possibility consistent with GUTS ideas with m({nu}{sub {tau}}) {approximately} 10{sup {minus}2} eV and m({nu} {sub {mu}}) {approximately} 10 {sup {minus}4} eV. The two cases can be distinguished by a measurement of the solar neutrinos from {sup {tau}}Be.
Date: November 1, 1992
Creator: Wolfenstein, L.
Partner: UNT Libraries Government Documents Department

Cosmic Closure: Relating the Ultimate Fate of Massive Stars and the Ultimate Fate of the Universe

Description: We give a brief overview of the status of core collapse supernova modeling, particularly as it pertains to predictions of neutrino signatures for the next galactic or near extragalactic supernova. We also consider the implications of neutrino mass for both the supernova mechanism and neutrino signature predictions.
Date: September 7, 1998
Creator: Bruenn, S.W. & Mezzacappa, A.
Partner: UNT Libraries Government Documents Department

Current status of MiniBooNE experiment

Description: This paper reviews the current status of the Fermilab mini-Booster neutrino experiment (MiniBooNE). The experiment began taking beam data in late August 2002. We describe the experiment, status of the beamline and detector, and show the first neutrino candidate events.
Date: March 24, 2003
Creator: Garcia, Fernanda G.
Partner: UNT Libraries Government Documents Department

Support Facility for a Graphite Target Neutrino Factory

Description: The Target Support Facility for a Neutrino Producing Research Facility extends from the pretarget, primary beam focusing region to the end of the decay channel. Technical components include the target, beam absorber, and solenoid magnetic-field focusing system. While the ultimate goal is to target about 4 MW of proton beam in the target area., smaller values and different target materials (e.g., low Z) are considered to facilitate the first step. As detailed in this report, a carbon target was chosen with an incident primary beam power of 1.5 MW, The target is embedded in a high-field solenoid magnet of 20 T, followed by a transition section channel, where the field tapers down to 1.25 T. An iterative design process has been carried out which optimizes Monte Carlo code flux projections with realistic magnetic-field parameters. The severe radiation environment and component shielding requirements strongly influence design choices. The overall system design includes the capture and decay channel solenoids, the design parameters of which were provided by the National High Magnetic Field Laboratory. This design balances resistive and superconducting magnet contributions. Facility requirements, including shielding, remote handling, radioactive water system, etc. are based on the final design goal of 4 MW. The extent of the Target Support Facility and radiation-handling equipment includes the 50-m decay channel, where remote-handling operations are also required.
Date: August 1, 2000
Creator: Spampinato, P.T.; Chesser, J.B.; Gabriel, T.A.; Gallmeier, F.X.; Haines, J.R.; Lillie, R.A. et al.
Partner: UNT Libraries Government Documents Department

Solar core homology, solar neutrinos and helioseismology

Description: Precise numerical standard solar models (SSMs) now agree with one another and with helioseismological observations in the convective and outer radiative zones. Nevertheless these models obscure how luminosity, neutrino production and g-mode core helioseismology depend on such inputs as opacity and nuclear cross sections. Although the Sun is not homologous, its inner core by itself is chemically evolved and almost homologous, because of its compactness, radiative energy transport, and ppI-dominated luminosity production. We apply luminosity-fixed homology transformations to the core to estimate theoretical uncertainties in the SSM and to obtain a broad class of non-SSMs, parameterized by central temperature and density and purely radiative energy transport in the core. 25 refs., 3 figs., 3 tabs.
Date: December 1995
Creator: Bludman, S. A. & Kennedy, D. C.
Partner: UNT Libraries Government Documents Department