1,288 research outputs found
Precision on leptonic mixing parameters at future neutrino oscillation experiments
We perform a comparison of the different future neutrino oscillation
experiments based on the achievable precision in the determination of the
fundamental parameters theta_{13} and the CP phase, delta, assuming that
theta_{13} is in the range indicated by the recent Daya Bay measurement. We
study the non-trivial dependence of the error on delta on its true value. When
matter effects are small, the largest error is found at the points where CP
violation is maximal, and the smallest at the CP conserving points. The
situation is different when matter effects are sizable. As a result of this
effect, the comparison of the physics reach of different experiments on the
basis of the CP discovery potential, as usually done, can be misleading. We
have compared various proposed super-beam, beta-beam and neutrino factory
setups on the basis of the relative precision of theta_{13} and the error on
delta. Neutrino factories, both high-energy or low-energy, outperform
alternative beam technologies. An ultimate precision on theta_{13} below 3% and
an error on delta of < 7^{\circ} at 1 sigma (1 d.o.f.) can be obtained at a
neutrino factory.Comment: Minor changes, matches version accepted in JHEP. 30 pages, 9 figure
Potential of optimized NOvA for large theta(13) & combined performance with a LArTPC & T2K
NOvA experiment has reoptimized its event selection criteria in light of the
recently measured moderately large value of theta(13). We study the improvement
in the sensitivity to the neutrino mass hierarchy and to leptonic CP violation
due to these new features. For favourable values of deltacp, NOvA sensitivity
to mass hierarchy and leptonic CP violation is increased by 20%. Addition of 5
years of neutrino data from T2K to NOvA more than doubles the range of deltacp
for which the leptonic CP violation can be discovered, compared to stand alone
NOvA. But for unfavourable values of deltacp, the combination of NOvA and T2K
are not enough to provide even a 90% C.L. hint of hierarchy discovery.
Therefore, we further explore the improvement in the hierarchy and CP violation
sensitivities due to the addition of a 10 kt liquid argon detector placed close
to NOvA site. The capabilities of such a detector are equivalent to those of
NOvA in all respects. We find that combined data from 10 kt liquid argon
detector (3 years of nu + 3 years of nubar run), NOvA (6 years of nu + 6 years
of nubar run) and T2K (5 years of nu run) can give a close to 2 sigma hint of
hierarchy discovery for all values of deltacp. With this combined data, we can
achieve CP violation discovery at 95% C.L. for roughly 60% values of deltacp.Comment: 22 pages, 24 pdf figures, 5 tables. In the appendix, new results are
presented with conservative choices of central values of oscillation
parameters. New references are added. Accepted in JHE
Requirements for a New Detector at the South Pole Receiving an Accelerator Neutrino Beam
There are recent considerations to increase the photomultiplier density in
the IceCube detector array beyond that of DeepCore, which will lead to a lower
detection threshold and a huge fiducial mass for the neutrino detection. This
initiative is known as "Phased IceCube Next Generation Upgrade" (PINGU). We
discuss the possibility to send a neutrino beam from one of the major
accelerator laboratories in the Northern hemisphere to such a detector. Such an
experiment would be unique in the sense that it would be the only neutrino beam
where the baseline crosses the Earth's core. We study the detector requirements
for a beta beam, a neutrino factory beam, and a superbeam, where we consider
both the cases of small theta_13 and large theta_13, as suggested by the recent
T2K and Double Chooz results. We illustrate that a flavor-clean beta beam best
suits the requirements of such a detector, in particular, that PINGU may
replace a magic baseline detector for small values of theta_13 -- even in the
absence of any energy resolution capability. For large theta_13, however, a
single-baseline beta beam experiment cannot compete if it is constrained by the
CERN-SPS. For a neutrino factory, because of the missing charge identification
possibility in the detector, a very good energy resolution is required. If this
can be achieved, especially a low energy neutrino factory, which does not
suffer from the tau contamination, may be an interesting option for large
theta_13. For the superbeam, where we use the LBNE beam as a reference,
electron neutrino flavor identification and statistics are two of the main
limitations. Finally, we demonstrate that, at least in principle, neutrino
factory and superbeam can measure the density of the Earth's core to the
sub-percent level for sin^2 2theta_13 larger than 0.01.Comment: 34 pages, 15 figures. Minor changes and accepted in JHE
Probing the Neutrino Mass Hierarchy with Super-Kamiokande
We show that for recently discovered large values of theta(13), a superbeam
with an average neutrino energy of ~ 5 GeV, such as those being proposed at
CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino
mass hierarchy at 5 sigma in less than two years irrespective of the true
hierarchy and CP phase. The measurement relies on the near resonant matter
effect in the numu to nue oscillation channel, and can be done counting the
total number of appearance events with just a neutrino beam.Comment: 16 pages, 7 pdf figures, 2 tables. Format changed and text extended.
Four new pdf figures added. Dependency of the result on 1-3 mixing angle
discussed. Conclusions unchanged. Accepted in JHE
Mass hierarchy discrimination with atmospheric neutrinos in large volume ice/water Cherenkov detectors
Large mass ice/water Cherenkov experiments, optimized to detect low energy
(1-20 GeV) atmospheric neutrinos, have the potential to discriminate between
normal and inverted neutrino mass hierarchies. The sensitivity depends on
several model and detector parameters, such as the neutrino flux profile and
normalization, the Earth density profile, the oscillation parameter
uncertainties, and the detector effective mass and resolution. A proper
evaluation of the mass hierarchy discrimination power requires a robust
statistical approach. In this work, the Toy Monte Carlo, based on an extended
unbinned likelihood ratio test statistic, was used. The effect of each model
and detector parameter, as well as the required detector exposure, was then
studied. While uncertainties on the Earth density and atmospheric neutrino flux
profiles were found to have a minor impact on the mass hierarchy
discrimination, the flux normalization, as well as some of the oscillation
parameter (\Delta m^2_{31}, \theta_{13}, \theta_{23}, and \delta_{CP})
uncertainties and correlations resulted critical. Finally, the minimum required
detector exposure, the optimization of the low energy threshold, and the
detector resolutions were also investigated.Comment: 23 pages, 16 figure
Toxic Epidermal Necrolysis after Pemetrexed and Cisplatin for Non-Small Cell Lung Cancer in a Patient with Sharp Syndrome
Background: Pemetrexed is an antifolate drug approved for maintenance and second-line therapy, and, in combination with cisplatin, for first-line treatment of advanced nonsquamous non-small cell lung cancer. The side-effect profile includes fatigue, hematological and gastrointestinal toxicity, an increase in hepatic enzymes, sensory neuropathy, and pulmonary and cutaneous toxicity in various degrees. Case Report: We present the case of a 58-year-old woman with history of Sharp's syndrome and adenocarcinoma of the lung, who developed toxic epidermal necrolysis after the first cycle of pemetrexed, including erythema, bullae, extensive skin denudation, subsequent systemic inflammation and severe deterioration in general condition. The generalized skin lesions occurred primarily in the previous radiation field and responded to immunosuppressive treatment with prednisone. Conclusion: Although skin toxicity is a well-known side effect of pemetrexed, severe skin reactions after pemetrexed administration are rare. Caution should be applied in cases in which pemetrexed is given subsequent to radiation therapy, especially in patients with pre-existing skin diseases
Analysis of the Temporal Organization of Sleep Spindles in the Human Sleep EEG Using a Phenomenological Modeling Approach
The sleep electroencephalogram (EEG) is characterized by typical oscillatory patterns such as sleep spindles and slow waves. Recently, we proposed a method to detect and analyze these patterns using linear autoregressive models for short (≈ 1 s) data segments. We analyzed the temporal organization of sleep spindles and discuss to what extent the observed interevent intervals correspond to properties of stationary stochastic processes and whether additional slow processes, such as slow oscillations, have to be assumed. We have found evidence for such an additional slow process, most pronounced in sleep stage 2
Aharonov-Bohm interference in topological insulator nanoribbons
Topological insulators represent novel phases of quantum matter with an
insulating bulk gap and gapless edges or surface states. The two-dimensional
topological insulator phase was predicted in HgTe quantum wells and confirmed
by transport measurements. Recently, Bi2Se3 and related materials have been
proposed as three-dimensional topological insulators with a single Dirac cone
on the surface and verified by angle-resolved photoemission spectroscopy
experiments. Here, we show unambiguous transport evidence of topological
surface states through periodic quantum interference effects in layered
single-crystalline Bi2Se3 nanoribbons. Pronounced Aharonov-Bohm oscillations in
the magnetoresistance clearly demonstrate the coverage of two-dimensional
electrons on the entire surface, as expected from the topological nature of the
surface states. The dominance of the primary h/e oscillation and its
temperature dependence demonstrate the robustness of these electronic states.
Our results suggest that topological insulator nanoribbons afford novel
promising materials for future spintronic devices at room temperature.Comment: 5 pages, 4 figures, RevTex forma
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