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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

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

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

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

What have we learned about the solar interior from solar oscillations?

Description: After a brief review of the discovery and properties of solar oscillations, I summarize the significant advances in our knowledge of the Sun`s interior structure achieved by using solar oscillation frequency data. I discuss the surprising solar interior rotation profile; the precise determination of the convection zone depth; the convection zone helium abundance; evidence for diffusive settling of helium during the Sun`s 4.5 billion year lifetime; and the Sun`s central structure and implications for the solar neutrino problem.
Date: December 31, 1995
Creator: Guzik, J.A.
Partner: UNT Libraries Government Documents Department

The Russian-American gallium solar neutrino experiment

Description: The Russian-American Gallium solar neutrino Experiment (SAGE) is described. The solar neutrino flux measured by 31 extractions through October, 1993 is presented. The result of 69 {+-} 10{sub {minus}7}{sup +5} SNU is to be compared with a standard solar model prediction of 132 SNU. The status of a {sup 51}Cr neutrino source irradiation to test the overall operation of the experiment is also presented.
Date: August 1, 1995
Creator: Elliott, S.R.; Wilkerson, J.F. & Abdurashitov, J.N.
Partner: UNT Libraries Government Documents Department

The solar neutrino problem: Neither astrophysics nor oscillations?

Description: There is no consistent solar model which can describe all experimental data on the solar neutrinos. The problem can be formulated essentially in a model independent way. The key points are the comparison of the Homestake and the Kamiokande data as well as the comparison of the GALLEX and SAGE results with minimal signal estimated from the solar luminosity. It is argued that in such a compaxison one should use the Homestake-II data (only after 1986) with caution. The results of the model independent analysis show strong suppression of the beryllium neutrino flux. The data can be well described by the resonant flavor conversion. For the ``low flux model`` which can accommodate the Kamiokande signal, a consistent solution can be found for the neutrino mass squared difference {Delta}m{sup 2} = (0.3 - 1.0) {center_dot} {sup {minus}5} 10 eV{sup 2} and values of mixing angle sin {sup 2} 2{theta} > 5 {center_dot} 10{sup {minus}5} eV{sup 2} and values of mixing angle sin {sup 2} 2{theta} (``very small mixing solution``).
Date: June 1, 1994
Creator: Smirnov, A. Y.
Partner: UNT Libraries Government Documents Department

Radiochemical Solar Neutrino Experiments - Successful and Otherwise.

Description: Over the years, several different radiochemical systems have been proposed as solar neutrino detectors. Of these, two achieved operating status and obtained important results that helped to define the current field of neutrino physics: the first solar-neutrino experiment, the Chlorine Detector ({sup 37}Cl) that was developed by chemist Raymond Davis and colleagues at the Homestake Mine, and the subsequent Gallium ({sup 71}Ga) Detectors that were operated by (a) the SAGE collaboration at the Baksan Laboratory and (b) the GALLEX/GNO collaborations at the Gran Sasso National Laboratory. These experiments have been extensively discussed in the literature and in many previous International Neutrino Conferences. In this paper, I present important updates to the results from SAGE and GALLEX/GNO. I also review the principles of the radiochemical detectors and briefly describe several different detectors that have been proposed. In light of the well-known successes that have been subsequently obtained by real-time neutrino detectors such as Kamiokande, Super-Kamiokande, SNO, and KamLAND, I do not anticipate that any new radiochemical neutrino detectors will be built. At present, only SAGE is still operating; the Chlorine and GNO radiochemical detectors have been decommissioned and dismantled.
Date: May 25, 2008
Creator: Hahn,R.L.
Partner: UNT Libraries Government Documents Department

On the mass eigenstate purity of Boron-8 solar neutrinos

Description: We give a brief report on our recent paper, Ref. [1], in which we calculate the {nu}{sub 2} mass eigenstate purity of {sup 8}B solar neutrinos as 91 {+-} 2%.
Date: January 1, 2006
Creator: Parke, Stephen J.; /Fermilab; Nunokawa, Hiroshi; /Rio de Janeiro, Pont. U. Catol.; Zukanovich Funchal, Renata & U., /Sao Paulo
Partner: UNT Libraries Government Documents Department

Current Experiments in Particle Physics (September 1996)

Description: This report contains summaries of current and recent experiments in Particle Physics. Included are experiments at BEPC (Beijing), BNL, CEBAF, CERN, CESR, DESY, FNAL, Frascati, ITEP (Moscow), JINR (Dubna), KEK, LAMPF, Novosibirsk, PNPI (St. Petersburg), PSI, Saclay, Serpukhov, SLAC, and TRIUMF, and also several proton decay and solar neutrino experiments. Excluded are experiments that finished taking data before 1991. Instructions are given for the World Wide Web (WWW) searching of the computer database (maintained under the SLAC-SPIRES system) that contains the summaries. This report contains full summaries of 180 approved current and recent experiments in elementary particle physics. The focus of the report is on selected experiments which directly contribute to our better understanding of elementary particles and their properties such as masses, widths or lifetimes, and branching fractions.
Date: September 1, 1996
Creator: Galic, H.; Lehar, F.; Klyukhin, V.I.; Ryabov, Yu.G.; Bilak, S.V.; Illarionova, N.S. et al.
Partner: UNT Libraries Government Documents Department

Long Baseline Neutrino Beams and Large Detectors

Description: It is amazing to acknowledge that in roughly 70 years from when the existence of the neutrino was postulated, we are now contemplating investigating the mysteries of this particle (or particles) requiring and utilizing detectors of 300 ktons , distances of 1,000-2,000 kilometers, beam intensities of megawatts and underground depth of 5,000 feet. This evolution has evolved slowly, from the experimental discovery of the neutrino in 1956, to the demonstration that there were two neutrinos in 1962 and three and only three by 1991. The great excitement occurred in the 2000's coming from the study of solar and atmospheric neutrinos in which neutrinos were observed to oscillate and therefore have mass. Although the absolute mass of any of the neutrinos has yet to be determined (the upper limit is less than I electron volt) the difference in this square of these masses has been measured, yielding a value of (2.3 {+-} .2) 10{sup -3} ev{sup 2} for atmospheric neutrinos and (7.6 {+-} .2) 10{sup -5} ev{sup 2} for solar neutrinos. In addition their mixing angles were found to be 45{sup o} for atmospheric neutrinos and 34{sup o} for solar neutrinos. This present state of knowledge on neutrinos is pictorially displayed in Fig. 1. Of course, mixing between flavors had already been observed in the quark sector as exemplified by the Cabbibo-Kobayashi-Meskawa Matrix. It was therefore natural to extend this formalism to the lepton sector involving unitary 3 x 3 matrices and one CP violating phase. This is shown in Fig. 2 for the two sectors, quark and leptons including the Jarlskog invariant (J).
Date: October 27, 2008
Creator: Samios,N.P.
Partner: UNT Libraries Government Documents Department

Development of a compact 20 MeV gamma-ray source for energy calibration at the Sudbury Neutrino Observatory

Description: The Sudbury Neutrino Observatory (SNO) is a real-time neutrino detector under construction near Sudbury, Ontario, Canada. SNO collaboration is developing various calibration sources in order to determine the detector response completely. This paper describes briefly the calibration sources being developed by the collaboration. One of these, a compact {sup 3}H(p,{gamma}){sup 4}He source, which produces 20-MeV {gamma}-rays, is described.
Date: December 31, 1995
Creator: Poon, A.W.P.; Browne, M.C.; Robertson, R.G.H.; Waltham, C.E. & Kherani, N.P.
Partner: UNT Libraries Government Documents Department

Low energy solar neutrino experiments: The Soviet American Gallium Experiment (SAGE). Final report, August 12, 1988--October 31, 1994

Description: Two {sup 71}Ga experiments are currently in operation. The first is the 60 ton Soviet American Gallium Experiment (SAGE) at Baksan, which has recently reported a signal level of 73+18/{minus}16(stat)+5/{minus}7(syst) SNU; the second is the 30 ton GALLEX experiment at Gran Sasso, which sees 87{+-}14{+-}7 SNU. Both results are consistent, and both suggest a neutrino flux level low compared to the total expected from standard solar model calculations. It is not possible, however, to make a case for flux levels lower than the p-p prediction. Assuming the experiments are correct (Neutrino source calibrations are planned for both SAGE and GALLEX in the near future.), it is not at all clear yet whether the answer lies with the neutrino physics, solar physics, or a combination of both. Nevertheless, though solar model effects cannot be ruled out, if the Homestake and Kamiokande results are taken at face value, then these two experiments alone imply that neutrino oscillations or some similar particle physics result must be present to some degree. This report reviews the SAGE experiment and recent results. Non-radiochemical experiments are also discussed, with an emphasis on the Kamiokande water Cerenkov results.
Date: April 1, 1995
Partner: UNT Libraries Government Documents Department

A Bayesian analysis of the solar neutrino problem

Description: We illustrate how the Bayesian approach can be used to provide a simple but powerful way to analyze data from solar neutrino experiments. The data are analyzed assuming that the neutrinos are unaltered during their passage from the Sun to the Earth. We derive quantitative and easily understood information pertaining to the solar neutrino problem.
Date: September 1, 1996
Creator: Bhat, C.M.; Bhat, P.C.; Paterno, M. & Prosper, H.B.
Partner: UNT Libraries Government Documents Department

SO(10) SUSY GUT model with a U(1) x Z2 x Z2 flavor s

Description: An SO(10) SUSY GUT model which leads to maximal atmospheric neutrino mixing and the LMA solar neutrino solution, developed in collaboration with S.M. Barr, is briefly described. Since the model is quantitatively predictive, it can be used to assess the need for a neutrino factory, as shown in collaboration with S. Geer.
Date: November 1, 2001
Creator: Albright, Carl H.
Partner: UNT Libraries Government Documents Department

NUFACT00: Interface between machine and physics working group summary

Description: The goal of Working Group 3 at NUFACT00 was to arrive at a set of neutrino factory parameters, taking into account physics needs and accelerator limitations. Fortunately there has been much work on both the machine design and the physics phenomenology since the first neutrino factory proposal based on a very intense muon source was made in November 1997. In addition the discussions and consensus at NUFACT99 formed a solid foundation for the phenomenological work done between NUFACT99 and NUFACT00. In particular, the agreement between various calculations of the neutrino oscillation physics possibilities at a neutrino factory gives us some confidence that the physics needs for oscillation physics are well understood if three flavor oscillation provides the right theoretical framework to describe the atmospheric and solar neutrino deficits. If it turns out that there is a surprise in store for us (for example, the LSND {nu}{sub {mu}} {r_arrow} {nu}{sub e} results are confirmed) then there may be a strong case for lower intensity and/or lower energy and shorter baseline experiments than described in the following. We can hope for a surprise, but since we can't count on one our considerations are based on more conventional three flavor oscillation scenarios.
Date: January 23, 2001
Creator: Cadenas, Juan Jose Gomez & Mori, Steve Geer and Yoshi
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{sup 2} {approx} 10{sup -10} - 10{sup -9} eV{sup 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 {le} {theta} {le} {pi}/2 when determining the allowed values of the neutrino oscillation parameters.
Date: May 18, 2000
Creator: Friedland, Alexander
Partner: UNT Libraries Government Documents Department

Status of the MINOS Experiment

Description: We report on the status of the MINOS long baseline neutrino experiment presently under construction at the Fermi National Accelerator Laboratory and the Soudan mine. There is growing evidence that the solar neutrino and atmospheric neutrino anomalies [1] are the result of neutrino oscillations. The MINOS experiment is a long baseline neutrino oscillation experiment designed to study the region of parameter space indicated by the SuperKamiokande atmospheric neutrino results [2]. The experiment consists of two detectors, one with a mass of 980 tons located at Fermilab (the near detector) and the other of mass 5400 tons located 731 km away in the Soudan mine in northern Minnesota (the far detector). The third component is the neutrino beam which is currently under construction at Fermilab.
Date: March 17, 2003
Creator: Buckley-Geer, Elizabeth
Partner: UNT Libraries Government Documents Department

Neutrino oscillations in noisy media

Description: The authors develop the Redfield equation for delta-correlated gaussian noise and apply it to the case of two neutrino flavor or spin precession in the presence of a noisy matter density or magnetic field, respectively. The criteria under which physical fluctuations can be well approximated by the delta-correlated gaussian noise for the above cases are examined. Current limits on the possible neutrino magnetic moment and solar magnetic field suggest that a reasonably noisy solar magnetic field would not appreciably affect the solar electron neutrino flux. However, if the solar electron density has fluctuations of a few percent of the local density and a small enough correlation length, the MSW effect is suppressed for a range of parameters.
Date: May 27, 1994
Creator: Loreti, F. N. & Balantekin, A. B.
Partner: UNT Libraries Government Documents Department


Description: A model based on SUSY SO(10) combined with SU(2) family symmetry is constructed. In contrast with the commonly used effective operator approach, 126-dimensional Higgs fields are utilized to construct the Yukawa sector. R-parity symmetry is thus preserved at low energies. The symmetric mass textures arising from the left-right symmetry breaking chain of SO(10) give rise to very good predictions for quark and lepton masses and mixings. The prediction for sin2{beta} agrees with the average of current bounds from BaBar and Belle. In the neutrino sector, our predictions are in good agreement with results from atmospheric neutrino experiments. Our model accommodates the LMA solution to the solar neutrino anomaly. The prediction of our model for the |U{sub ev{sub 3}}| element in the MNS matrix is close to the sensitivity of current experiments; thus the validity of our model can be tested in the near future. We also investigate the correlation between the |U{sub ev{sub 3}}| element and tan{sup 2} {theta}{sub {circle_dot}} in a general two-zero neutrino mass texture.
Date: July 20, 2003
Partner: UNT Libraries Government Documents Department

Results from SAGE II

Description: The Russian-American Gallium solar neutrino Experiment (SAGE) began the second phase of operation (SAGE II) in September of 1992. Monthly measurements of the integral flux of solar neutrinos have been made with 55 tonnes of gallium. The K-peak results of the first nine runs of SAGE II give a capture rate of 66{sub -13}{sup +18} (stat) {sub -7}{sup +5} (sys) SNU. Combined with the SAGE I result of 73{sub -16}{sup +18} (stat) {sub -7}{sup 5} (sys) SNU, the capture rate is 69{sub -11}{sup +11} (stat) {sub -7}{sup +5} (sys) SNU. This represents only 52%--56% of the capture rate predicted by different Standard Solar Models.
Date: October 1, 1994
Creator: Nico, J. S.
Partner: UNT Libraries Government Documents Department

Landau-Zener Treatments of Solar Neutrino Oscillations

Description: The authors present a simple derivation of Landau-Zener formulae for nonadiabatic level crossings for linear and exponential density profiles. The derivation depends on a single assumption that applies somewhat differently to the exponential and linear cases, providing some insight into the relationship between the respective formulae. They note that one exponential Landau-Zener formula in common use is only approximately correct. Comparisons with exact calculations are made.
Date: January 1, 1995
Creator: Bruggen, Marcus; Haxton, W. C. & Qian, Y. Z.
Partner: UNT Libraries Government Documents Department