Search for dinucleon decay into pions at Super-Kamiokande

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA search for dinucleon decay into pions with the Super-Kamiokande detector has been performed with an exposure of 282.1 kiloton-years. Dinucleon decay is a process that violates baryon number by two units. We present the first search for dinucleon decay to pions in a large water-Cherenkov detector. The modes O16(pp)→C14π+π+, O16(pn)→N14π+π0, and O16(nn)→O14π0π0 are investigated. No significant excess in the Super-Kamiokande data has been found, so a lower limit on the lifetime of the process per oxygen nucleus is determined. These limits are τpp→π+π+>7.22×1031 years, τpn→π+π0>1.70×1032 years, and τnn→π0π0>4.04×1032 years. The lower limits on each mode are about 2 orders of magnitude better than previous limits from searches for dinucleon decay in ironWe gratefully acknowledge the cooperation of the Kamioka Mining and Smelting Company. The Super- Kamiokande experiment has been built and operated from funding by the Japanese Ministry of Education, Culture, Sports, Science and Technology, the United States Department of Energy, and the U.S. National Science Foundation. This work was partially supported by the Research Foundation of Korea (BK21 and KNRC), the Korean Ministry of Science and Technology, the National Science Foundation of China, the European Union FP7 (DS laguna-lbno PN-284518 and ITN invisibles GA-2011- 289442), the National Science and Engineering Research Council (NSERC) of Canada, and the Scinet and West-grid consortia of Compute Canad

Limits on sterile neutrino mixing using atmospheric neutrinos in Super-Kamiokande

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMWe present limits on sterile neutrino mixing using 4,438 live-days of atmospheric neutrino data from the Super-Kamiokande experiment. We search for fast oscillations driven by an eV2-scale mass splitting and for oscillations into sterile neutrinos instead of tau neutrinos at the atmospheric mass splitting. When performing both of these searches we assume that the sterile mass splitting is large, allowing sin2(Δm2L/4E) to be approximated as 0.5, and we assume that there is no mixing between electron neutrinos and sterile neutrinos (|Ue4|2=0). No evidence of sterile oscillations is seen and we limit |Uμ4|2 to less than 0.041 and |Uτ4|2 to less than 0.18 for Δm2>0.1eV2 at the 90% C.L. in a 3+1 framework. The approximations that can be made with atmospheric neutrinos allow these limits to be easily applied to 3+N models, and we provide our results in a generic format to allow comparisons with other sterile neutrino modelsThe authors gratefully acknowledge the cooperation of the Kamioka Mining and Smelting Company. Super-K has been built and operated from funds provided by the Japanese Ministry of Education, Culture, Sports, Science and Technology, the U.S. Department of Energy, and the U.S. National Science Foundation. This work was partially supported by the Research Foundation of Korea (BK21 and KNRC), the Korean Ministry of Science and Technology, the National Science Foundation of China, the European Union FP7 (DS laguna-lbno PN- 284518 and ITN invisibles GA-2011-289442) the National Science and Engineering Research Council (NSERC) of Canada, and the Scinet and Westgrid consortia of Compute Canad

Test of Lorentz invariance with atmospheric neutrinos

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the nonperturbative standard model extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was observed, so limits are set on the renormalizable isotropic SME coefficients in the eμ, μτ, and eτ sectors, improving the existing limits by up to 7 orders of magnitude and setting limits for the first time in the neutrino μτ sector of the SMEWe would like to thank A. Kostelecky for his advice and support and we are grateful to J. S. Diaz for working closely with us to calculate and implement the Lorentz-violating oscillation probabilities. The authors gratefully acknowledge the cooperation of the Kamioka Mining and Smelting Company. Super-K has been built and operated from funds provided by the Japanese Ministry of Education, Culture, Sports, Science and Technology, the U.S. Department of Energy, and the U.S. National Science Foundation. This work was partially supported by the Research Foundation of Korea (BK21 and KNRC), the Korean Ministry of Science and Technology, the National Science Foundation of China, the European Union FP7 (DS laguna-lbno PN- 284518 and ITN invisibles GA-2011-289442), the National Science and Engineering Research Council (NSERC) of Canada, and the Scinet and Westgrid consortia of Compute Canad

Search for neutrinos in Super-Kamiokande associated with gravitational-wave events GW150914 and GW151226

Astrophysical Journal Letters 830.1 (2016): L11 reproduced by permission of the AASWe report the results from a search in Super-Kamiokande for neutrino signals coincident with the first detected gravitational-wave events, GW150914 and GW151226, as well as LVT151012, using a neutrino energy range from 3.5 MeV to 100 PeV. We searched for coincident neutrino events within a time window of ±500 s around the gravitational-wave detection time. Four neutrino candidates are found for GW150914, and no candidates are found for GW151226. The remaining neutrino candidates are consistent with the expected background events. We calculated the 90% confidence level upper limits on the combined neutrino fluence for both gravitational-wave events, which depends on event energy and topologies. Considering the upward-going muon data set (1.6 GeV-100 PeV), the neutrino fluence limit for each gravitational-wave event is 14-37 (19-50) cm-2 for muon neutrinos (muon antineutrinos), depending on the zenith angle of the event. In the other data sets, the combined fluence limits for both gravitational-wave events range from 2.4 ×104 to 7.0 ×109 cm-2The Super-Kamiokande experiment has been built and operated from funding by the Japanese Ministry of Education, Culture, Sports, Science and Technology, the U.S. Department of Energy, and the U.S. National Science Foundation. Some of us have been supported by funds from the Korean Research Foundation (BK21 and KNRC), the National Research Foundation of Korea (NRF-20110024009), the European Union (H2020 RISE-GA641540-SKPLUS), the Japan Society for the Promotion of Science, the National Natural Science Foundation of China under grant No. 11235006, and the Scinet and Westgrid consortia of Compute Canad

Search for Nucleon and Dinucleon Decays with an Invisible Particle and a Charged Lepton in the Final State at the Super-Kamiokande Experiment

Artículo escrito por muchos autores, sólo se referencian el primero, los autores que firman como Universidad Autónoma de Madrid y el grupo de colaboración en el caso de que aparezca en el artículoSearch results for nucleon decays p→e+X, p→μ+X, n→νγ (where X is an invisible, massless particle) as well as dinucleon decays np→e+ν, np→μ+ν, and np→τ+ν in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of 273.4 kton·yr, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of τp→e+X>7.9×1032yr, τp→μ+X>4.1×1032yr, τn→νγ>5.5×1032yr, τnp→e+ν>2.6×1032yr, τnp→μ+ν>2.2×1032yr, and τnp→τ+ν>2.9×1031yr at a 90% confidence level are obtained. Some of these searches are novelThe Super- Kamiokande experiment was built and has been operated with funding from the Japanese Ministry of Education, Culture, Sports, Science and Technology, the U.S. Department of Energy, and the U.S. National Science Foundatio

The ZEUS Forward Plug Calorimeter with Lead-Scintillator Plates and WLS Fiber Readout

A Forward Plug Calorimeter (FPC) for the ZEUS detector at HERA has been built as a shashlik lead-scintillator calorimeter with wave length shifter fiber readout. Before installation it was tested and calibrated using the X5 test beam facility of the SPS accelerator at CERN. Electron, muon and pion beams in the momentum range of 10 to 100 GeV/c were used. Results of these measurements are presented as well as a calibration monitoring system based on a $^{60}$Co source.Comment: 38 pages (Latex); 26 figures (ps

Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar

Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or high-turbulence regimes, but in general the radar-retrieved values correspond well with the in situ measurements. Root mean square differences are typically a factor of 4-6 relative to any given magnitude of dissipation rate. These differences are no larger than those found when comparing dissipation rates computed from tetheredballoon and meteorological tower-mounted sonic anemometer measurements made at spatial distances of a few hundred meters. Temporal lag analyses suggest that approximately half of the observed differences are due to spatial sampling considerations, such that the anticipated radar-based retrieval uncertainty is on the order of a factor of 2-3. Moreover, radar retrievals are clearly able to capture the vertical dissipation rate structure observed by the in situ sensors, while offering substantially more information on the time variability of turbulence profiles. Together these evaluations indicate that radar-based retrievals can, at a minimum, be used to determine the vertical structure of turbulence in Arctic stratocumulus clouds

Renal prostacyclin influences renal function in non-azotemic cirrhotic patients treated with furosemide

The influence of prostaglandins on renal function changes induced by furosemide was analyzed in 21 non-azotemic cirrhotic patients with ascites. Patients were studied in two periods of 120 min immediately before and after furosemide infusion (20 mg, ev). Furosemide caused an increase in creatinine clearance in 15 patients (group A: 99 +/- 7 vs. 129 +/- 5 ml/min; mean +/- S.E.) and a reduction in the remaining six (group B: 102 +/- 13 vs. 71 +/- 9 ml/min). Parallel changes were observed in the urinary excretion of 6-Keto-prostaglandin-F1 alpha (metabolite of renal prostacyclin) which augmented after furosemide in 14 of the 15 patients from group A (478 +/- 107 vs. 1034 +/- 159 pg/min, p less than 0.001) and decreased in all patients from group B (1032 +/- 240 vs. 548 +/- 136 pg/min, p less than 0.05). In contrast, the urinary excretion of prostaglandin E2 was stimulated by furosemide in all patients (group A, 92 +/- 19 vs. 448 +/- 60 pg/min, p less than 0.001; and group B, 209 +/- 63 vs. 361 +/- 25 pg/min, p less than 0.05). In all of the patients furosemide-induced changes (post- minus pre-furosemide values) in creatinine clearance were closely correlated in a direct and linear fashion with those in 6-Keto-prostaglandin-F1 alpha (r = 0.74; p less than 0.001). These changes were associated with a higher furosemide-induced natriuresis in group A than in group B (641 +/- 68 vs. 302 +/-- 46 mumol/min, p less than 0.001