The Sudbury Neutrino Observatory (SNO) has confirmed the standard solar model and neutrino oscillations through the observation of neutrinos from the solar core. In this paper we present a search for ...neutrinos associated with sources other than the solar core, such as gamma-ray bursts and solar flares. We present a new method for looking for temporal coincidences between neutrino events and astrophysical bursts of widely varying intensity. No correlations were found between neutrinos detected in SNO and such astrophysical sources.
Results are reported from a joint analysis of Phase I and Phase II data from the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is T{sub eff}=3.5 MeV, the lowest ...analysis threshold yet achieved with water Cherenkov detector data. In units of 10{sup 6} cm{sup -2} s{sup -1}, the total flux of active-flavor neutrinos from {sup 8}B decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the {sup 8}B neutrino energy spectrum, is found to be PHI{sub NC}=5.140{sub -0.158}{sup +0.160}(stat){sub -0.117}{sup +0.132}(syst). These uncertainties are more than a factor of 2 smaller than previously published results. Also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons. A fit to the Sudbury Neutrino Observatory data in which the free parameters directly describe the total {sup 8}B neutrino flux and the energy-dependent nu{sub e} survival probability provides a measure of the total {sup 8}B neutrino flux PHI{sub {sup 8}{sub B}}=5.046{sub -0.152}{sup +0.159}(stat){sub -0.123}{sup +0.107}(syst). Combining these new results with results of all other solar experiments and the KamLAND reactor experiment yields best-fit values of the mixing parameters of theta{sub 12}=34.06{sub -0.84}{sup +1.16} degrees and DELTAm{sub 21}{sup 2}=7.59{sub -0.21}{sup +0.20}x10{sup -5} eV{sup 2}. The global value of PHI{sup 8}{sub B} is extracted to a precision of {sub -2.95}{sup +2.38}%. In a three-flavor analysis the best fit value of sin{sup 2}theta{sub 13} is 2.00{sub -1.63}{sup +2.09}x10{sup -2}. This implies an upper bound of sin{sup 2}theta{sub 13}<0.057 (95% C.L.).
The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle
$\theta _{13}$
have led to a re-evaluation of the physics ...potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal
$\sin ^22\theta _{23}$
, the octant of
$\theta _{23}$
, and the mass hierarchy, in addition to the measurements of
$\delta _{{\rm CP}}$
,
$\sin ^2\theta _{23}$
, and
$\Delta m^2_{32}$
, for various combinations of
$\nu$
-mode and
$\bar {\nu }$
-mode data-taking.
With an exposure of
$7.8\times 10^{21}$
protons-on-target, T2K can achieve 1
$\sigma$
resolution of 0.050 (0.054) on
$\sin ^2\theta _{23}$
and
$0.040\ (0.045)\times 10^{-3}\,\rm {eV}^2$
on
$\Delta m^2_{32}$
for 100% (50%) neutrino beam mode running assuming
$\sin ^2\theta _{23}=0.5$
and
$\Delta m^2_{32} = 2.4\times 10^{-3}\,\hbox {eV}^2$
. T2K will have sensitivity to the CP-violating phase
$\delta _{\rm {CP}}$
at 90% C.L. or better over a significant range. For example, if
$\sin ^22\theta _{23}$
is maximal (i.e.
$\theta _{23}=45^\circ$
) the range is
$-115^\circ \lt \delta _{\rm {CP}}\lt -60^\circ$
for normal hierarchy and
$+50^\circ \lt \delta _{\rm {CP}}\lt +130^\circ$
for inverted hierarchy. When T2K data is combined with data from the NO
$\nu$
A experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero
$\delta _{{\rm CP}}$
is substantially increased compared to if each experiment is analyzed alone.
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has ...achieved a low energy threshold with improved sensitivity to low-mass (<10 GeV/c2) dark matter particles. We present an analysis of the final CDMSlite dataset, taken with a different detector than was used for the two previous CDMSlite datasets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile likelihood methods to search for a dark matter signal in the presence of backgrounds. We achieve an energy threshold of 70 eV and significantly improve the sensitivity for dark matter particles with masses between 2.5 and 10 GeV/c2 compared to previous analyses. We set an upper limit on the dark matter-nucleon scattering cross section in germanium of 5.4×10-42 cm2 at 5 GeV/c2, a factor of ~2.5 improvement over the previous CDMSlite result.
Summary Lung cancer is the most common cause of cancer deaths worldwide. The two broad histological subtypes of lung cancer are small-cell lung cancer (SCLC), which is the cause of 15% of cases, and ...non-small-cell lung cancer (NSCLC), which accounts for 85% of cases and includes adenocarcinoma, squamous-cell carcinoma, and large-cell carcinoma. Although NSCLC and SCLC are commonly thought to be different diseases owing to their distinct biology and genomic abnormalities, the idea that these malignant disorders might share common cells of origin has been gaining support. This idea has been supported by the unexpected findings that a subset of NSCLCs with mutated EGFR return as SCLC when resistance to EGFR tyrosine kinase inhibitors develops. Additionally, other case reports have described the coexistence of NSCLC and SCLC, further challenging the commonly accepted view of their distinct lineages. Here, we summarise the published clinical observations and biology underlying tumours with combined SCLC and NSCLC histology and cancers that transform from adenocarcinoma to SCLC. We also discuss pre-clinical studies pointing to common potential cells of origin, and speculate how the distinct paths of differentiation are determined by the genomics of each disease.
Results are reported from a search for low-multiplicity neutrino bursts in the Sudbury Neutrino Observatory. Such bursts could indicate the detection of a nearby core-collapse supernova explosion. ...The data were taken from Phase I (1999 November-2001 May), when the detector was filled with heavy water, and Phase II (2001 July-2003 August), when NaCl was added to the target. The search was a blind analysis in which the potential backgrounds were estimated and analysis cuts were developed to eliminate such backgrounds with 90% confidence before the data were examined. The search maintained a greater than 50% detection probability for standard supernovae occurring at a distance of up to 60 kpc for Phase I and up to 70 kpc for Phase II. No low-multiplicity bursts were observed during the data-taking period.
Nuclear-recoil energy scale in CDMS II silicon dark-matter detectors Agnese, R.; Anderson, A. J.; Aramaki, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2018, Letnik:
905, Številka:
C
Journal Article
Recenzirano
The Cryogenic Dark Matter Search (CDMS II) experiment aims to detect dark matter particles that elastically scatter from nuclei in semiconductor detectors. The resulting nuclear-recoil energy ...depositions are detected by ionization and phonon sensors. Neutrons produce a similar spectrum of low-energy nuclear recoils in such detectors, while most other backgrounds produce electron recoils. The absolute energy scale for nuclear recoils is necessary to interpret results correctly. The energy scale can be determined in CDMS II silicon detectors using neutrons incident from a broad-spectrum 252Cf source, taking advantage of a prominent resonance in the neutron elastic scattering cross section of silicon at a recoil (neutron) energy near 20 (182) keV. Results indicate that the phonon collection efficiency for nuclear recoils is 4.8+0.7-0.9% lower than for electron recoils of the same energy. Comparisons of the ionization signals for nuclear recoils to those measured previously by other groups at higher electric fields indicate that the ionization collection efficiency for CDMS II silicon detectors operated at ~4 V/cm is consistent with 100% for nuclear recoils below 20 keV and gradually decreases for larger energies to ~75% at 100 keV. The impact of these measurements on previously published CDMS II silicon results is small.
We report the result of a blinded search for Weakly Interacting Massive Particles (WIMPs) using the full SuperCDMS Soudan dataset. With an exposure of 1690 kg days, a single event was observed after ...unblinding, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4x10^-44 (1.0x10^-44) cm^2 at 46 GeV/c^2 . These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12 GeV/c^2.
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