1,542 research outputs found
The role of -induced reactions on lead and iron in neutrino detectors
We have calculated cross sections and branching ratios for neutrino induced
reactions on ^{208}Pb and ^{56}Fe for various supernova and
accelerator-relevant neutrino spectra. This was motivated by the facts that
lead and iron will be used on one hand as target materials in future neutrino
detectors, on the other hand have been and are still used as shielding
materials in accelerator-based experiments. In particular we study the
inclusive ^{56}^{56}Co and ^{208}^{208}Bi cross
sections and calculate the neutron energy spectra following the decay of the
daughter nuclei. These reactions give a potential background signal in the
KARMEN and LSND experiment and are discussed as a detection scheme for
supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the
neutron-emission following the neutrino-induced neutral-current excitation of
^{56}Fe and ^{208}Pb.Comment: 23 pages (including 7 figures
Triple resonant four-wavemixing boosts the yield of continuous coherent VUV generation
Continuous-wave coherent radiation in the vacuum ultraviolet (VUV)wavelength
region at 121 nm will be essential for future laser-cooling of trapped
antihydrogen [1]. Cold antihydrogen will enable both tests of the fundamental
symmetry between matter and antimatter at unprecedented experimental precision
[2] and also experiments in antimatter gravity [3]. Another fascinating
application of narrowband continuous laser radiation in the VUV is quantum
information processing using single trapped ions in Rydberg-states [4, 5]. Here
we describe highly efficient continuous four-wave mixing in the VUV by using
three different fundamental wavelengths with a sophisticated choice of
detunings to resonances of the nonlinear medium. Up to 6 microwatts of vacuum
ultraviolet radiation at 121 nm can be generated which corresponds to an
increase of three orders of magnitude in efficiency.Comment: 11 pages, 3 figure
Muon capture on nuclei with N > Z, random phase approximation, and in-medium renormalization of the axial-vector coupling constant
We use the random phase approximation to describe the muon capture rate on
Ca,Ca, Fe, Zr, and Pb. With
Ca as a test case, we show that the Continuum Random Phase
Approximation (CRPA) and the standard RPA give essentially equivalent
descriptions of the muon capture process. Using the standard RPA with the free
nucleon weak form factors we reproduce the experimental total capture rates on
these nuclei quite well. Confirming our previous CRPA result for the
nuclei, we find that the calculated rates would be significantly lower than the
data if the in-medium quenching of the axial-vector coupling constant were
employed.Comment: submitted to Phys. Rev.
Neutrino induced transitions between the ground states of the A=12 triad
Neutrino induced reactions on C, an ingredient of liquid
scintillators, have been studied in several experiments. We show that for
currently available neutrino energies, 300 MeV, calculated
exclusive cross sections CN for both muon
and electron neutrinos are essentially model independent, provided the
calculations simultaneously describe the rates of several other reactions
involving the same states or their isobar analogs. The calculations agree well
with the measured cross sections, which can be therefore used to check the
normalization of the incident neutrino spectrum and the efficiency of the
detector.Comment: 9 pages REVTEX, 2 postscript figures, text and figures available at
http://www.krl.caltech.edu/preprints/MAP.htm
Neutrino Detection using Lead Perchlorate
We discuss the possibility of using lead perchlorate as a neutrino detector.
The primary neutrino interactions are given along with some relevant properties
of the material.Comment: 2 pages, 2 figures, TAUP-99, TEX fil
Neutrino and antineutrino cross sections in C
We extend the formalism of weak interaction processes, obtaining new
expressions for the transition rates, which greatly facilitate numerical
calculations, both for neutrino-nucleus reactions and muon capture. We have
done a thorough study of exclusive (ground state) properties of B and
N within the projected quasiparticle random phase approximation (PQRPA).
Good agreement with experimental data is achieved in this way. The inclusive
neutrino/antineutrino () reactions C(N
and C(B are calculated within both the PQRPA, and
the relativistic QRPA (RQRPA). It is found that the magnitudes of the resulting
cross-sections: i) are close to the sum-rule limit at low energy, but
significantly smaller than this limit at high energies both for and
, ii) they steadily increase when the size of the configuration
space is augmented, and particulary for energies MeV,
and iii) converge for sufficiently large configuration space and final state
spin.Comment: Proceedings of the International Nuclear Physics Conference 2010,
Vancouver, BC - Canada 4-9 Jul 201
Neutrino-Nucleus Cross Section Measurements using Stopped Pions and Low Energy Beta Beams
Two new facilities have recently been proposed to measure low energy
neutrino-nucleus cross sections, the nu-SNS (Spallation Neutron Source) and low
energy beta beams. The former produces neutrinos by pion decay at rest, while
the latter produces neutrinos from the beta decays of accelerated ions. One of
the uses of neutrino-nucleus cross section measurements is for supernova
studies, where typical neutrino energies are 10s of MeV. In this energy range
there are many different components to the nuclear response and this makes the
theoretical interpretation of the results of such an experiment complex.
Although even one measurement on a heavy nucleus such as lead is much
anticipated, more than one data set would be still better. We suggest that this
can be done by breaking the electron spectrum down into the parts produced in
coincidence with one or two neutrons, running a beta beam at more than one
energy, comparing the spectra produced with pions and a beta beam or any
combination of these.Comment: 6 pages, 6 figure
Signal for supernova and neutrinos in water \v{C}erenkov detectors
We suggest that photons with energies between 5 and 10 MeV, generated by the
() and () reactions on O, constitute a
signal which allows a unique identification of supernova and
neutrinos in water \v{C}erenkov detectors. We calculate the yield of
such events and estimate that a few hundred of them would be detected
in Superkamiokande for a supernova at 10 kpc distance.Comment: 8 pages, RevTex 3.0, figures and text available at
http://www.krl.caltech.edu/preprints/MAP.htm
Can guided introspection help avoid rationalization of meat consumption? Mixed-methods results of a pilot experimental study
The need for reducing meat consumption in affluent countries is increasingly recognized as crucial to minimizing carbon footprint. However, confronting individuals with rational arguments can prompt emotional discomfort, which is often relieved by engaging in rationalization processes stabilizing current consumption patterns. Mindfulness research suggests that making people aware of their emotional reactions through introspection can reduce these rationalization processes. In this mixed-method pilot experimental study, we inquired whether a single guided introspection, inspired by the micro-phenomenological interview technique, can alter individuals' experience of and abilities to deal with cognitive dissonance. Furthermore, we asked if such an intervention can stimulate attitude or intention changes concerning meat consumption. After inducing cognitive dissonance by exposing participants to pictures of the slaughter of a cow, the intervention group (n = 36) participated in the guided introspection, while the control group (n = 39) played solitaire. Self-report questionnaire measures of emotional discomfort, rationalization strategies, and attitudes towards meat consumption were administered before and after the intervention. Also, open-ended responses to participants’ experience of the study were analyzed. Quantitative results show significantly lower negative attitudes toward reducing meat consumption in the intervention group compared to the control group (partial 2 = 0.107). Qualitative results indicate that these participants are more aware of negative emotions while engaging less in rationalization strategies. We conclude that our study indicates some potential for guided introspection to affect dissonance resolution and provide suggestions for future research
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