摘要:

This paper reports the latest indications of an anomaly in the measurements of atmospheric neutrinos. New results from Soudan-2 and Super-Kamiokande provide evidence that the ratio of&ngr;&mgr;to&ngr;einteractions is not as expected. High energy Super-Kamiokande data indicates the cause is a deficit of upward-going&ngr;&mgr;,and the zenith angle dependence of the effect is consistent with neutrino oscillations. Upward-going muon measurements by several detectors are discussed, but in total they provide inconclusive evidence for the anomaly. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56606

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The current status of neutrino oscillations is reviewed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56594

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A preliminary measurement ofsin2&hthinsp;&thgr;Win&ngr;−Ndeep inelastic scattering from the NuTeV experiment is presented. Using separate neutrino and antineutrino beams, NuTeV is able to determinesin2&hthinsp;&thgr;Wwith low systematic errors. NuTeV measuressin2&hthinsp;&thgr;W(on–shell)=0.2253±0.0019(stat)±0.0010(syst),which impliesMW=80.26±0.11&hthinsp;GeV.Expectations are also presented for the NuTeV search for&ngr;&mgr;→&ngr;&tgr;and&ngr;&mgr;→&ngr;eoscillations using the measured neutral to charged-current ratio. The future BooNE experiment is described which searches for&ngr;&mgr;→&ngr;eappearance and&ngr;&mgr;disappearance oscillations using a new neutrino beam created from the Fermilab 8 GeV Booster accelerator. The experiment is designed to cover definitively the&dgr;m2/sin2&hthinsp;2&thgr;region associated with the possible oscillation signal from the LSND experiment and to measure accurately the oscillation parameters if a signal is observed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56584

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The energy dependence of the neutrino oscillation length in vacuum is examined in a theoretically unbiased way by expanding it in a Laurent series. The three simplest power laws are compared with experimental data and potential physical mechanisms beyond the usual mass mixing mechanism are discussed for the two survivors. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56607

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The model-independent “box” parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing–matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations amongn⩾3flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56585

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The Standard Cosmological Model of the 1980’s is no more. I describe the definitive evidence that the density of matter is insufficient to result in a flat universe, as well as the mounting evidence that the cosmological constant is not zero. I finally discuss the implications of these results for particle physics and direct searches for non-baryonic dark matter. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56598

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

This talk reviews the original motivation for the axion as a solution to the strong CP problem and the constraints that have been placed on the axion by experimental searches and by astrophysical and cosmological considerations. As a result of the bounds, the axion mass is presently restricted to a window extending from about10−2&hthinsp;eVto about10−6&hthinsp;eV.In this window, axions are a form of cold dark matter. It is possible to detect galactic halo axions by stimulating their conversion to photons in a laboratory magnetic field. I’ll report on two experiments of this type, one at Lawrence Livermore National Laboratory and the other at Kyoto University. I’ll also discuss what can be learned about the structure of our galactic halo if a signal is found. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56599

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Having a neutrino component of dark matter provides the best existing model for structure formation in the universe. If at least one light sterile neutrino exists, this hot dark matter can be accommodated, along with the solar&ngr;edeficit, the anomalous&mgr;/eratio produced by atmospheric neutrinos, and the candidate events for&ngr;&mgr;→&ngr;e(or&ngr;¯&mgr;→&ngr;¯e) from the LSND experiment. This neutrino mass pattern also provides a robust solution to problems presently making heavy-element synthesis by suppernovae seem impossible, and it could help resolve a possible discrepancy between big bang nucleosynthesis theory and observations. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56600

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We present the scientific motivation and conceptual design of the P. Auger Observatory. Two giant ground arrays of water Cˇerenkov tanks overlooked by fluorescence detectors will cover an area of 3000 km2each. They will be build in the Southern and Northern hemisphere to provide full sky coverage. The total aperture of14000&hthinsp;km2srwill allow to study all observable aspects of cosmic rays from below 10 EeV up to arbitrarily high energies with an unprecedented accuracy. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56586

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The observation of cosmic-ray events above the Greisen–Kuzmin–Zatsepin (GZK) cutoff of5×1019&hthinsp;eVchallenges orthodox modeling. We discuss a possible solution which uses Standard Model (SM) physics augmented only by ≲ eV neutrino masses as suggested by solar, atmospheric, and terrestrial neutrino detection and the cosmological preference for a hot dark matter component. In this scheme, cosmic ray neutrinos from distant, highest-energy sources annihilate relatively nearby on the relic-neutrino background to produce “Z-bursts”, highly-collimated, highly-boosted(&ggr;Z∼1011)hadronic jets. ¿From the SM and hot Big Bang cosmology, the probability for each neutrino flavor at its resonant energy to annihilate within the halo of our galactic supercluster is likely within an order of magnitude of 1&percent;. The kinematics of the annihilation are completely determined by the neutrino masses and the properties of theZboson. The burst energy isER=4&hthinsp;(eV/m&ngr;)×1021&hthinsp;eV,and the burst content includes, on average, thirty photons and 2.7 nucleons with super-GZK energies. Several tests of the neutrino annihilation hypothesis are indicated. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56587

出版商:AIP    

年代:1998

数据来源: AIP