897 research outputs found
Low Energy Neutrino Physics after SNO and KamLAND
In the recent years important discoveries in the field of low energy neutrino
physics (E in the MeV range) have been achieved. Results of the
solar neutrino experiment SNO show clearly flavor transitions from to
. In addition, the long standing solar neutrino problem is
basically solved. With KamLAND, an experiment measuring neutrinos emitted from
nuclear reactors at large distances, evidence for neutrino oscillations has
been found. The values for the oscillation parameters, amplitude and phase,
have been restricted. In this paper the potential of future projects in low
energy neutrino physics is discussed. This encompasses future solar and reactor
experiments as well as the direct search for neutrino masses. Finally the
potential of a large liquid scintillator detector in an underground laboratory
for supernova neutrino detection, solar neutrino detection, and the search for
proton decay is discussed.Comment: Invited brief review, World Scientific Publishing Compan
Why does the probe value effect emerge in working memory? Examining the biased attentional refreshing account
People are able to prioritize more valuable information in working memory. The current study examined whether this value effect is due to the items of greater value being refreshed more than lower-value items during maintenance. To assess this possibility, we combined a probe value manipulation with a guided-refreshing procedure. Arrays of colored shapes were presented, and after a brief delay, participants reported the color of one randomly probed shape on a continuous color wheel. To manipulate probe value, one item was indicated as more valuable than the rest prior to encoding (i.e., worth more notional points), or all items were indicated as equally valuable. To guide refreshing, in some trials, two arrows were presented during maintenance, each arrow cueing the spatial location of one item. Participants were told to âthink ofâ (i.e., refresh) the cued item. If value boosts are driven by attentional refreshing, cueing an item to be refreshed should enhance performance for items that are of low or equal value, but not items of high value, as these items would be refreshed regardless of the cue. This pattern of outcomes was observed, providing support for the hypothesis that attentional refreshing at least partially accounts for probe value effects in working memory
The General Theory of Quantum Field Mixing
We present a general theory of mixing for an arbitrary number of fields with
integer or half-integer spin. The time dynamics of the interacting fields is
solved and the Fock space for interacting fields is explicitly constructed. The
unitary inequivalence of the Fock space of base (unmixed) eigenstates and the
physical mixed eigenstates is shown by a straightforward algebraic method for
any number of flavors in boson or fermion statistics. The oscillation formulas
based on the nonperturbative vacuum are derived in a unified general
formulation and then applied to both two and three flavor cases. Especially,
the mixing of spin-1 (vector) mesons and the CKM mixing phenomena in the
Standard Model are discussed emphasizing the nonperturbative vacuum effect in
quantum field theory
R2D2 - a symmetric measurement of reactor neutrinos free of systematical errors
We discuss a symmetric setup for a reactor neutrino oscillation experiment
consisting of two reactors separated by about 1 km, and two symmetrically
placed detectors, one close to each reactor. We show that such a configuration
allows a determination of which is essentially free of
systematical errors, if it is possible to separate the contributions of the two
reactors in each detector sufficiently. This can be achieved either by
considering data when in an alternating way only one reactor is running or by
directional sensitivity obtained from the neutron displacement in the detector.Comment: 11 pages, 3 figures, clarifications added, some numbers in relation
with the neutron displacement corrected, version to appear in JHE
Reactor Neutrino Experiments with a Large Liquid Scintillator Detector
We discuss several new ideas for reactor neutrino oscillation experiments
with a Large Liquid Scintillator Detector. We consider two different scenarios
for a measurement of the small mixing angle with a mobile
source: a nuclear-powered ship, such as a submarine or an
icebreaker, and a land-based scenario with a mobile reactor. The former setup
can achieve a sensitivity to at the 90%
confidence level, while the latter performs only slightly better than Double
Chooz. Furthermore, we study the precision that can be achieved for the solar
parameters, and , with a mobile reactor
and with a conventional power station. With the mobile reactor, a precision
slightly better than from current global fit data is possible, while with a
power reactor, the accuracy can be reduced to less than 1%. Such a precision is
crucial for testing theoretical models, e.g. quark-lepton complementarity.Comment: 18 pages, 3 figures, 2 tables, revised version, to appear in JHEP,
Fig. 1 extended, Formula added, minor changes, results unchange
Establishing a nu_{mu,tau} Component in the Solar Neutrino Flux
We point out that the recoil electron kinetic energy spectra in the nu-e
elastic scattering are different for incident nu_{e} or nu_{mu,tau}, and hence
one can in principle establish the existence of the nu_{mu,tau} component in
the solar neutrino flux by fitting the shape of the spectrum. This would be a
new model-independent test of the solar neutrino oscillation in a single
experiment, free from astrophysical and nuclear physics uncertainties. For the
^7Be neutrinos, it is possible to determine the nu_{mu,tau} component at
BOREXINO or KamLAND, if the background is sufficiently low. Note that this
effect is different from the distortion in the incident neutrino energy
spectrum, which has been discussed in the literature.Comment: 12 pages, 3 figures, uses psfig. Figures reorganized, one corrected,
conclusions unchange
Quantum Field Theory of Meson Mixing
We have developed a quantum field theoretic framework for scalar and
pseudoscalar meson mixing and oscillations in time. The unitary inequivalence
of the Fock space of base (unmixed) eigenstates and the physical mixed
eigenstates is proven and shown to lead to a rich condensate structure. This is
exploited to develop formulas for two flavor boson oscillations in systems of
arbitrary boson occupation number. The mixing and oscillation can be understood
in terms of vacuum condensate which interacts with the bare particles to induce
non-trivial effects. We apply these formulas to analyze the mixing of
with and comment on the system. In addition, we consider the
mixing of boson coherent states, which may have future applications in the
construction of meson lasers.Comment: 12 pages, 3 figures; Eqs.(10-12) corrected, leading to new physical
insights; added paragraph under Eq.(24) explaining physical interpretation of
mixing in terms of vacuum condensation; references added and minor typo
correcte
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