Further Evidence for the Decay K+ to pi+ neutrino-antineutrino

Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute 0.15 pm 0.05 events. The branching ratio is B=1.57^{+1.75}_{-0.82} 10^{-10}.Comment: 10 pages, 2 figure

Improved Measurement of the K+ to pi+ nu nubar Branching Ratio

An additional event near the upper kinematic limit for K+ to pi+ nu nubar has been observed by Experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+ to pi+ nu nubar)= 1.47 (+1.30, - 0.89) x 10-10 based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9

Land-use change and carbon stocks: regional assessment of sugarcane areas in Brazil.

Abstract: In agricultural product Life Cycle Assessment (LCA), emissions or removals of carbon (C) from land-use change can highly affect the global warming. The aim of this study was to evaluate the impacts of biomass C values and stock change factors on land use change (LUC) emissions in areas of sugarcane expansion in Brazil. In this study, we used stratified random sample in order to estimate changes in land cover through geotechnologies and associated C stocks from literature data. For that, the total area was stratified by three criteria: soil type, % of native vegetation in 1998 and age of sugarcane plantation in 2018. The sample size represented 12.8% of the studied area (172,000 ha). To this end, a matrix of primary combinations was combined with spatial data such as land cover in 1998, soil types, biomes and Köppen climate classification. Estimates of C stock changes in soil and biomass were calculated the Stock-Difference Method, according to IPCC Guidelines and specialized literature. Respecting the uncertainties, this approach allowed to have an estimate of C balance in sugarcane fields at the regional level in Brazil. Three main recommendations: (i) values of FMG> 1.0 (FMG, stock change factor for management regime), should be used for sugarcane, but future research ratification is necessary; (ii) biomass C values of sugarcane biomass above 5 tonnes C ha-1 should be used, especially when sugarcane is harvested without burning; and (iii) as there is still no relationship between level of pasture degradation and C content in soil, biomass C values and pasture FMG should be carefully chosen in pasture conversion to sugarcane

Upper Limit on the Branching Ratio for the Decay π0→ννˉ\pi^0 \to \nu \bar\nu

A sample of kinematically identified $K^+ \to \pi^+ \pi^0$ decays obtained with the E949 detector was used to search for the helicity-suppressed decay $\pi^0 \to \nu \bar{\nu}$ resulting in an upper limit of $2.7\times10^{-7}$ at 90% confidence level.The upper limit is also applicable to $\pi^0$ decays into unknown weakly interacting particles.Comment: 9 pages, 3 figures; no change in the results, accepted for publication in Physical Review

Study of the decay K+ => pi+,nu,nubar in the momentum region 140<Ppi<199 MeV/c

Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay K+ => pi+,nu,nubar in the pion momentum region 140 < P_pi < 199 MeV/c in an exposure of 1.71e12 stopped kaons with an estimated total background of 0.93+-0.17(stat.)+0.32-0.24(syst.) events. This brings the total number of observed K+ => pi+,nu,nubar events to seven. Combining this observation with previous results, assuming the pion spectrum predicted by the standard model, results in a branching ratio of (1.73+1.15-1.05)e-10. An interpretation of the results for alternative models of the decay K^ => pi+,nothing is also presented.Comment: Submitted to Phys.Rev.

MACHO Alert 95-30 : First Real-Time Observation of Extended Source Effects in Gravitational Microlensing

We present analysis of MACHO Alert 95-30, a dramatic gravitational microlensing event towards the Galactic bulge whose peak magnification departs significantly from the standard point-source microlensing model. Alert 95-30 was observed in real-time by the Global Microlensing Alert Network (GMAN), which obtained densely sampled photometric and spectroscopic data throughout the event. We interpret the light-curve ``fine structure'' as indicating transit of the lens across the extended face of the source star. This signifies resolution of a star several kpc distant. We find a lens angular impact parameter theta_{min}/theta_{source} = 0.715 +/- 0.003. This information, along with the radius and distance of the source, provides an additional constraint on the lensing system. Spectroscopic and photometric data indicate the source is an M4 III star of radius 61 +/- 12 Rsun, located on the far side of the bulge at 9 kpc. We derive a lens angular velocity, relative to the source, of 21.5 +/- 4.9 km/s/kpc, where the error is dominated by uncertainty in the source radius. Likelihood analysis yields a median lens mass of 0.67{+2.53}{-0.46} Msun, located with 80% probability in the Galactic bulge at a distance of 6.93{+1.56}{-2.25} kpc. If the lens is a main-sequence star, we can include constraints on the lens luminosity. This modifies our estimates to M_lens = 0.53{+0.52}{-0.35} Msun and D_lens = 6.57{+0.99}{-2.25} kpc. Spectra taken during the event show that the absorption line equivalent widths of H alpha and the TiO bands near 6700 A vary, as predicted for microlensing of an extended source. This is most likely due to center-to-limb variation in the stellar spectral lines. These data demonstrate the feasibility of using microlensing limb crossings as a tool to probe stellar atmospheres directly.Comment: 32 pages including 6 tables, and 15 figures; Uses AASTeX 4.0; submitted to The Astrophysical Journa

Measurement of the K+→π+ννˉK^+\to\pi^+\nu\bar{\nu} Branching Ratio

Experiment E949 at Brookhaven National Laboratory studied the rare decay \$K^+\to\pi^+\nu\bar{\nu}$ and other processes with an exposure of $1.77\times 10^{12}$ $K^+$'s. The data were analyzed using a blind analysis technique yielding one candidate event with an estimated background of $0.30\pm0.03$ events. Combining this result with the observation of two candidate events by the predecessor experiment E787 gave the branching ratio {\calB}(K^+\to\pi^+\nu\bar{\nu})=(1.47^{+1.30}_{-0.89})\times 10^{-10}, consistent with the Standard Model prediction of $(0.74\pm0.20)\times 10^{-10}$. This is a more detailed report of results previously published in Physical Review Letters.Comment: 99 pages, 32 figures, 12 tables. Added authors, corrected typos and modify the text suggested by the referees. Accepted for publication in PR