541 research outputs found
CP Violation and Matter Effect in Long Baseline Neutrino Oscillation Experiments
We show simple methods how to separate pure CP violating effect from matter
effect in long baseline neutrino oscillation experiments with three generations
of neutrinos. We give compact formulae for neutrino oscillation probabilities
assuming one of the three neutrino masses (presumably tau-neutrino mass) to be
much larger than the other masses and the effective mass due to matter effect.
Two methods are shown: One is to observe envelopes of the curves of oscillation
probabilities as functions of neutrino energy; a merit of this method is that
only a single detector is enough to determine the presence of CP violation. The
other is to compare experiments with at least two different baseline lengths;
this has a merit that it needs only narrow energy range of oscillation data.Comment: 17 pages + 9 eps figures, LaTeX, errors are correcte
CP and T violation test in neutrino oscillation
We examine how large violation of CP and T is allowed in long base line
neutrino experiments. When we attribute only the atmospheric neutrino anomaly
to neutrino oscillation we may have large CP violation effect. When we
attribute both the atmospheric neutrino anomaly and the solar neutrino deficit
to neutrino oscillation we may have a sizable T violation effect proportional
to the ratio of two mass differences; it is difficult to see CP violation since
we can't ignore the matter effect. We give a simple expression for T violation
in the presence of matter.Comment: 12 pages + 2 eps figures, Latex, In order to avoid misunderstanding
we have refined our English and rewritten the parts which might be
misleading. Several typographical errors are correcte
Simulation of Atmospheric Muon and Neutrino Fluxes with CORSIKA
The fluxes of atmospheric muons and neutrinos are calculated by a three
dimensional Monte Carlo simulation with the air shower code CORSIKA using the
hadronic interaction models DPMJET, VENUS, GHEISHA, and UrQMD. For the
simulation of low energy primary particles the original CORSIKA has been
extended by a parametrization of the solar modulation and a microscopic
calculation of the directional dependence of the geomagnetic cut-off functions.
An accurate description for the geography of the Earth has been included by a
digital elevation model, tables for the local magnetic field in the atmosphere,
and various atmospheric models for different geographic latitudes and annual
seasons. CORSIKA is used to calculate atmospheric muon fluxes for different
locations and the neutrino fluxes for Kamioka. The results of CORSIKA for the
muon fluxes are verified by an extensive comparison with recent measurements.
The obtained neutrino fluxes are compared with other calculations and the
influence of the hadronic interaction model, the geomagnetic cut-off and the
local magnetic field on the neutrino fluxes is investigated.Comment: revtex, 19 pages, 19 Postscript figures, submitted to Phys. Rev.
Experimental and Theoretical Results for Weak Charge Current Backward Proton Production
In this paper, we do three things in the study of deuteron break-up by high
energy neutrino beams. (1) We present previously unpublished data on neutrino
induced backward protons from deuteron targets; (2) we calculate the
contributions from both the two-nucleon (2N) and six-quark (6q) deuteron
components, which depend upon the overall normalization of the part that is 6q;
and (3) we suggest other signatures for distinguishing the 2N and 6q clusters.
We conclude that the 6q cluster easily explains the shape of the high momentum
backward proton spectrum, and its size is nicely explained if the amount of 6q
is one or a few percent by normalization of the deuteron. There is a crossover,
above which the 6q contribution is important or dominant, at 300--400 MeV/c
backward proton momentum.Comment: 8 pages, 5 figure
A first measurement of the interaction cross section of the tau neutrino
The DONuT experiment collected data in 1997 and published first results in
2000 based on four observed charged-current (CC) interactions. The
final analysis of the data collected in the experiment is presented in this
paper, based on protons on target using the 800 GeV
Tevatron beam at Fermilab. The number of observed CC interactions is
9, from a total of 578 observed neutrino interactions. We calculated the
energy-independent part of the tau-neutrino CC cross section (), relative to the well-known and cross sections. The
ratio / was found to be
. The CC cross section was found to be cm. Both results are in
agreement the Standard Model.Comment: 37 pages, 15 figure
A Study of Cosmic Ray Composition in the Knee Region using Multiple Muon Events in the Soudan 2 Detector
Deep underground muon events recorded by the Soudan 2 detector, located at a
depth of 2100 meters of water equivalent, have been used to infer the nuclear
composition of cosmic rays in the "knee" region of the cosmic ray energy
spectrum. The observed muon multiplicity distribution favors a composition
model with a substantial proton content in the energy region 800,000 -
13,000,000 GeV/nucleus.Comment: 38 pages including 11 figures, Latex, submitted to Physical Review
Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2
We have searched for the proton decay mode proton to neutrino K+ using the
one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained
from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for
occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0.
We found one candidate event consistent with background, yielding a limit,
tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters
Super-Kamiokande atmospheric neutrino data, zenith distributions, and three-flavor oscillations
We present a detailed analysis of the zenith angle distributions of
atmospheric neutrino events observed in the Super-Kamiokande (SK) underground
experiment, assuming two-flavor and three-flavor oscillations (with one
dominant mass scale) among active neutrinos. In particular, we calculate the
five angular distributions associated to sub-GeV and multi-GeV \mu-like and
e-like events and to upward through-going muons, for a total of 30 accurately
computed observables (zenith bins). First we study how such observables vary
with the oscillation parameters, and then we perform a fit to the experimental
data as measured in SK for an exposure of 33 kTy (535 days). In the two-flavor
mixing case, we confirm the results of the SK Collaboration analysis, namely,
that \nu_\mu\nu_\tau oscillations are preferred over \nu_\mu\nu_e,
and that the no oscillation case is excluded with high confidence. In the
three-flavor mixing case, we perform our analysis with and without the
additional constraints imposed by the CHOOZ reactor experiment. In both cases,
the analysis favors a dominance of the \nu_\mu\nu_\tau channel. Without
the CHOOZ constraints, the amplitudes of the subdominant \nu_\munu_e and
\nu_e\nu_\tau transitions can also be relatively large, indicating that,
at present, current SK data do not exclude sizable \nu_e mixing by themselves.
After combining the CHOOZ and SK data, the amplitudes of the subdominant
transitions are constrained to be smaller, but they can still play a
nonnegligible role both in atmospheric and other neutrino oscillation searches.
In particular, we find that the \nu_e appearance probability expected in long
baseline experiments can reach the testable level of ~15%.Comment: 35 pages (RevTeX), including 20 ps figures (with epsfig.sty
A New Upper Limit for the Tau-Neutrino Magnetic Moment
Using a prompt neutrino beam in which a nu_tau component was identified for
the first time, the nu_tau magnetic moment was measured based on a search for
an anomalous increase in the number of neutrino-electron interactions. One such
event was observed when 2.3 were expected from background processes, giving an
upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.Comment: 9 pages; 1 figur
Gravitational-wave research as an emerging field in the Max Planck Society. The long roots of GEO600 and of the Albert Einstein Institute
On the occasion of the 50th anniversary since the beginning of the search for
gravitational waves at the Max Planck Society, and in coincidence with the 25th
anniversary of the foundation of the Albert Einstein Institute, we explore the
interplay between the renaissance of general relativity and the advent of
relativistic astrophysics following the German early involvement in
gravitational-wave research, to the point when gravitational-wave detection
became established by the appearance of full-scale detectors and international
collaborations. On the background of the spectacular astrophysical discoveries
of the 1960s and the growing role of relativistic astrophysics, Ludwig Biermann
and his collaborators at the Max Planck Institute for Astrophysics in Munich
became deeply involved in research related to such new horizons. At the end of
the 1960s, Joseph Weber's announcements claiming detection of gravitational
waves sparked the decisive entry of this group into the field, in parallel with
the appointment of the renowned relativist Juergen Ehlers. The Munich area
group of Max Planck institutes provided the fertile ground for acquiring a
leading position in the 1970s, facilitating the experimental transition from
resonant bars towards laser interferometry and its innovation at increasingly
large scales, eventually moving to a dedicated site in Hannover in the early
1990s. The Hannover group emphasized perfecting experimental systems at pilot
scales, and never developed a full-sized detector, rather joining the LIGO
Scientific Collaboration at the end of the century. In parallel, the Max Planck
Institute for Gravitational Physics (Albert Einstein Institute) had been
founded in Potsdam, and both sites, in Hannover and Potsdam, became a unified
entity in the early 2000s and were central contributors to the first detection
of gravitational waves in 2015.Comment: 94 pages. Enlarged version including new results from further
archival research. A previous version appears as a chapter in the volume The
Renaissance of General Relativity in Context, edited by A. Blum, R. Lalli and
J. Renn (Boston: Birkhauser, 2020
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