1,720,973 research outputs found
MiniBooNE Oscillation Update
No full textWascko, Morgan. (2009). MiniBooNE Oscillation Update. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/52769
Reconstruction of neutrino induced neutral current neutral pion events with the T2K ND280 Tracker and ECAL
Get PDFT2K is a long baseline neutrino oscillation experiment in Japan. One of
the goals is to search for electron neutrino appearance at the far detector
(Super Kamiokande) in a muon neutrino beam produced 295 km away, to
make a measurement of the unknown neutrino oscillation angle [Symbol appears here. To view, please open pdf attachment]13. A
major background to this appearance search is neutral pions (π0) produced
in neutral current (NC) neutrino interactions. The π0s decay to photons,
which can in cases mimic the electron appearance signal.
The near detector of the experiment (ND280) has the capability of measuring
the rates of NCπ0 production processes. NCπ0 interactions in the
Tracker of the detector (plastic scintillator targets, and time projection
chambers for tracking charged particles) can be detected through photon
conversions in the electromagnetic calorimeter that surrounds the Tracker.
For these types of events, the photon reconstruction in the calorimeter has
to have good energy and angular resolutions.
This thesis describes the T2K experiment, the ND280 detector and its
offline software, and gives details on the ECal reconstruction of photons.
The performance of the reconstruction in relation to the π0 decay photons,
their energy and angular resolutions, is studied.
An analysis is presented for the reconstruction of NC π0s produced in
the trackers, with both photons converting in the downstream calorimeter, developed purely with Monte Carlo (with GENIE as the interaction generator),
and then applied to the first-year data from ND280. The Monte Carlo
expectation is 17.7 ± 1.1(stat) ± 4.9(syst) events, with 37 ± 4% NCπ0 purity;
21 events are seen in the first year data. The MC is consistent with data at
the 0.5σ level.
As a crosscheck, the same analysis is applied to a different Monte Carlo
production (using NEUT as the generator). The expectation from this
production is 16.8 ± 1.0(stat) ± 4.7(syst) events, with 30 ± 4% purity. This
is consistent with data at the 0.7σ level
T2K Status, Results, and Plans
No full textT2K is an accelerator-based long-baseline neutrino experiment in which a muon neutrino beam produced by JPARC in Tokai is sent 295 km across Japan to the Super-Kamiokande detector to study neutrino oscillations via the disappearance of muon neutrinos and the appearance of electron neutrinos. The T2K beam can be run in neutrino or antineutrino mode. Since the start of operations in 2010, T2K has conclusively observed muon neutrino to electron neutrino oscillations, and performed the most precise measurement of the muon neutrino and antineutrino disappearance parameters. These measurements are a new probe of unknown physics, including the possibility of observing CP violation in neutrino mixing. T2K has collected new neutrino and antineutrino data since the Neutrino 2016 conference. In this talk, we will present updated neutrino and antineutrino oscillation results with new data, and touch on other physics topics. Finally, the future prospects of the experiment, including the extension of the T2K program, T2K-II, will be presented
Study of [muon neutrino] disappearance in the T2K experiment
No full textA Vμ disappearance analysis performed on the dataset collected during the first
physics run of the T2K experiment is presented. This dataset represents an
accumulated exposure of 3.23 x10¹⁹ protons on target (POT). A total of eight
events passed all the selection criteria at the far detector, Super-Kamiokande,
with an expectation of 22.8 ± 4.8(stat)+3.7-3.7(syst).
A two flavor neutrino oscillation fit was performed with systematic uncertainties using a Markov Chain Monte Carlo method and a Bayesian approach.
The sin² 2θ23 oscillation parameter was constrained to the physical region.
Under these conditions, we found best fit values for the oscillation parameters
of sin² 2θ23 = 0.83+016-0.18 and Δm²32 = 2.9+0.8-1.0 x 10⁻³ eV²/c⁴
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Study of neutrino-induced neutral current neutral pion production in the T2K near detector
Get PDFThe T2K experiment is a long baseline neutrino oscillation experiment. The
most intense accelerator muon neutrino beam ever built is produced at the
J-PARC facility in Tokai, located on the east coast of Japan, and directed
(2.5 [degrees] off -axis) toward the Super-Kamiokande water Cherenkov detector, located
295 km away in the mountains of western Japan.
For the current T2K [Symbol appears here. To view, please open pdf attachment]e appearance analysis, 23% of the background at Super-
Kamiokande is from neutral current interactions that produce one π0 in the final state (NC 1π0). This study uses ND280 Run 2 data totalling 7.832 x 10 [to the power of 19] POT
and selects neutrino-induced NC 1π0 interactions in FGD1 and FGD2 where
both π0 decay photons convert in the barrel and downstream ECAL.
Overall, neglecting photon reconstruction efficiency, an efficiency of 22% and
purity of 16% is obtained. For the case where both π0 decay photons convert in
the downstream (barrel) ECAL an efficiency of 33% (12%) and purity of 43%
(9%) is achieved. When one photon converts in the barrel ECAL and the other
in the downstream ECAL the efficiency (purity) is 29% (16%).
Systematic uncertainties arising from cross-section model parameters and final state interactions, the neutrino flux prediction and the shape discrepancy between
ECAL variables in data and MC are evaluated. The predicted total number
of events when both photons convert in the downstream and barrel ECAL is
7.1± 2.3 (syst)± 0.5 (stat) and 31.6± 8.9 (syst) ±1.2 (stat), respectively. Whereas
when one decay photon is reconstructed in the barrel ECAL and the other in the
downstream ECAL the expected number of events is 38.1± 8.7 (syst) ±1.3 (stat).
The selected number of events in data is 5, 22 and 31, respectively, which agrees
with the prediction within errors.
The calibration of the time offsets for the barrel and downstream ECAL is
also presented in this thesis. The application of this calibration reduces the
timing resolution from 9 ns to approximately 2.5 ns, for high charge hits.Open Acces
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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