The Fermilab KTeV experiment has searched for lepton-flavor-violating decays of the K(L) meson in three decay modes. We observe no events in the signal region for any of the modes studied, and we set ...the following upper limits for their branching ratios at the 90% C.L.: BR(K(L) --> pi(0) micro(+/-) e(-/+)) <7.6 x 10(-11); BR(K(L) --> pi(0)pi(0) micro(+/-) e(-/+)) <1.7 x 10(-10); BR(pi(0) --> micro(+/-) e(-/+)) <3.6 x 10(-10). This result represents a factor of 82 improvement in the branching ratio limit for K(L) --> pi(0) micro(+/-) e(-/+) and is the first reported limit for K(L) --> pi(0)pi(0) micro(+/-) e(-/+).
We present a new determination of the parity of the neutral pion via the double Dalitz decay pi0-->e+e-e+e-. Our sample, which consists of 30,511 candidate decays, was collected from KL-->pi0pi0pi0 ...decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative pi0 parity and place a limit on scalar contributions to the pi0-->e+e-e+e- decay amplitude of less than 3.3% assuming CPT conservation. The pi0gamma*gamma* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be B(pi0-->e+e-e+e-)=(3.26+/-0.18)x10(-5).
Whereas etiological heterogeneity of the various types of schizophrenia has been repeatedly proposed, relatively few attempts have been made to separate the component diseases. Using a strategy ...focusing on bimodal distributions within several relevant domains of schizophrenia, we demonstrate that currently available data on schizophrenia patients are consistent with the hypothesis that some of these patients have an ongoing neurodegenerative disease, whereas others do not. We review studies (longitudinal and cross-sectional) documenting progressive increases in ventricular size, accelerated loss of brain tissues, progressive delays in treatment response, and neurochemical (magnetic resonance spectroscopy) and neurophysiological (P300) indices, all of which are consistent with ongoing cerebral degeneration in a significant subgroup of schizophrenia patients. These lines of evidence converge on a conceptualization of schizophrenia as being composed of several etiologically distinct processes, with one subset of psychotic patients evidencing progressive brain degeneration. We conclude with a discussion of possible etiologies for this condition.
We present a measurement of B(π0→e+e-γ)/B(π0→γγ), the Dalitz branching ratio, using data taken in 1999 by the E832 KTeV experiment at Fermi National Accelerator Laboratory. We use neutral pions from ...fully reconstructed KL decays in flight; the measurement is based on ~60 thousand KL→π0π0π0→γγγγe+e-γ decays. We normalize to KL→π0π0π0→6γ decays. We find B(π0→e+e-γ)/B(π0→γγ) (me+e->15 MeV/c2)=3.920±0.016(stat)±0.036(syst)×10-3. Using the Mikaelian and Smith prediction for the e+e- mass spectrum, we correct the result to the full e+e- mass range. The corrected result is B(π0→e+e-γ)/B(π0→γγ)=1.1559±0.0047(stat)±0.0106(syst)%. This result is consistent with previous measurements, and the uncertainty is a factor of 3 smaller than any previous measurement.
We present a measurement of B(π0→e+e−γ)/B(π0→γγ), the Dalitz branching ratio, using data taken in 1999 by the E832 KTeV experiment at Fermi National Accelerator Laboratory. We use neutral pions from ...fully reconstructed KL decays in flight; the measurement is based on ∼60 thousand KL→π0π0π0→γγγγe+e−γ decays. We normalize to KL→π0π0π0→6γ decays. We find B(π0→e+e−γ)/B(π0→γγ) (me+e−>15 MeV/c2)=3.920±0.016(stat)±0.036(syst)×10−3. Using the Mikaelian and Smith prediction for the e+e− mass spectrum, we correct the result to the full e+e− mass range. The corrected result is B(π0→e+e−γ)/B(π0→γγ)=1.1559±0.0047(stat)±0.0106(syst)%. This result is consistent with previous measurements, and the uncertainty is a factor of 3 smaller than any previous measurement.
Measurements of the decay KL-->e+ e- gamma Abouzaid, E; Arenton, M; Barker, A R ...
Physical review letters,
2007-Aug-03, 20070803, Letnik:
99, Številka:
5
Journal Article
Recenzirano
The E799-II (KTeV) experiment at Fermilab has collected 83 262 K(L)-->e+ e- gamma(gamma) events above a background of 79 events. We measure a decay width, normalized to the K(L)-->pi0pi0pi(D)0 ...(pi0-->gammagamma, pi0-->gammagamma, pi(D0-->e+ e- gamma(gamma)) decay width, of Gamma(K(L)-->e+e-gamma(gamma))/Gamma(K(L)-->pi0pi0pi(D)0)=(1.3302+/-0.0046(stat)+/-0.0102(syst)) x 10(-3). We also measure parameters of two K(L)gamma*gamma form factor models. In the Bergström-Massó-Singer parametrization, we find Calpha(K*)= -0.517 +/- 0.030(stat) +/- 0.022(syst). We separately fit for the first parameter of the D'Ambrosio-Isidori-Portolés model and find alpha(DIP)= -1.729 +/- 0.043(stat) +/- 0.028(syst).
Managing heavily manured soils for decreased P loss to waters requires improved understanding of the chemical and sorption-desorption characteristics of P in these soils. We used soils from ...agricultural fields receiving > or = 8 yr of dairy, poultry, swine manure or spent mushroom compost for the determination of P functional groups in NaOH-EDTA extracts by solution 31P nuclear magnetic resonance (NMR) spectroscopy, degree of P saturation (DPS), and P sorption-desorption isotherms. The 31P NMR results show that inorganic orthophosphate was the primary form of P in manure treated (79-93% of total extract P) and untreated soils (33-71%). Pyrophosphate and phosphate monoesters were identified in all soils, whereas phosphate diesters were present in small proportions (<3%) in only a few soils. Polyphosphate, a more condensed form of inorganic P, was present in seven out of nine manured soils (9-47 mg P kg-1, <2%) but absent in untreated soils. Concentrations of inositol hexakisphosphate (IHP), mostly myo-IHP plus some scyllo-IHP, were similar in manured soils (52-116 mg P kg-1, 2-8%) and untreated soils (43-137 mg P kg-1, 6-22%), suggesting a lack of IHP accumulation despite long-term manure applications, including poultry manures that are typically rich in IHP. Most of the treated soils had DPS approximately 80 to 90% compared with 11 to 33% for the untreated samples. Results from P sorption isotherms showed that potential P release was 3 to 30 times greater from treated than untreated soils. The lack of IHP accumulation in soils receiving long-term manure applications implies that manure-derived IHP may not be biologically and environmentally benign.
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