... Y. Wu,5 T. Yamanaka,8 and ED Zimmerman4 (KTeV Collaboration) University of Arizona, Tucson, A... more ... Y. Wu,5 T. Yamanaka,8 and ED Zimmerman4 (KTeV Collaboration) University of Arizona, Tucson, Arizona 85721 University of California at Los Angeles, Los Angeles, California 90095 3 University of California at San Diego, La Jolla, California 92093 4 The Enrico Fermi Institute ...
ABSTRACT The Pierre Auger Observatory in Malarg¨ue, Argentina, is designed to study the propertie... more ABSTRACT The Pierre Auger Observatory in Malarg¨ue, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 1018 eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that results from both analyses are compatible, and that the uncertainties are well understood. The measurements of the aerosol attenuation provided by the two procedures are currently used at the Pierre Auger Observatory to reconstruct air shower data.
We present the first observation of Xi0 beta decay, using the KTeV beam line and detector at Ferm... more We present the first observation of Xi0 beta decay, using the KTeV beam line and detector at Fermilab. We have identified 176 beta decay events after subtracting a 7 event background. Normalization to 41 024 simultaneously collected Xi0-->Lambda0pi0 decays yields a branching ratio of gamma\(Xi0-->Sigma+e-nu¯e\)/gammatotal = \(2.71+/-0.22statistical+/-0.31systematic\)×10-4. The flavor symmetric quark model calculation agrees with this result.
We report on a new measurement of the decay K L →π 0 γγ by the KTeV experiment at Fermilab. We de... more We report on a new measurement of the decay K L →π 0 γγ by the KTeV experiment at Fermilab. We determine the K L →π 0 γγ branching ratio to be (1.68±0.07±0.08)×10 -6 . Our data show the first evidence for a low-mass γγ signal as predicted by recent O(p 6 ) chiral ...
We report on two null searches, one for the spontaneous appearance of π + π - pairs, another for ... more We report on two null searches, one for the spontaneous appearance of π + π - pairs, another for a single π 0 , consistent with the decay of a long-lived neutral particle into hadrons and an unseen neutral particle. For the lowest level gluon-gluino bound state, known as the R 0 , ...
The branching ratio of the rare decay π 0 →e + e - has been measured in E799-II, a rare kaon deca... more The branching ratio of the rare decay π 0 →e + e - has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. We observed 275 candidate π 0 →e + e - events, with an expected background of 21.4±6.2 events which includes the ...
... Y. Wu,5 T. Yamanaka,8 and ED Zimmerman4 (KTeV Collaboration) University of Arizona, Tucson, A... more ... Y. Wu,5 T. Yamanaka,8 and ED Zimmerman4 (KTeV Collaboration) University of Arizona, Tucson, Arizona 85721 University of California at Los Angeles, Los Angeles, California 90095 3 University of California at San Diego, La Jolla, California 92093 4 The Enrico Fermi Institute ...
ABSTRACT The Pierre Auger Observatory in Malarg¨ue, Argentina, is designed to study the propertie... more ABSTRACT The Pierre Auger Observatory in Malarg¨ue, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 1018 eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that results from both analyses are compatible, and that the uncertainties are well understood. The measurements of the aerosol attenuation provided by the two procedures are currently used at the Pierre Auger Observatory to reconstruct air shower data.
We present the first observation of Xi0 beta decay, using the KTeV beam line and detector at Ferm... more We present the first observation of Xi0 beta decay, using the KTeV beam line and detector at Fermilab. We have identified 176 beta decay events after subtracting a 7 event background. Normalization to 41 024 simultaneously collected Xi0-->Lambda0pi0 decays yields a branching ratio of gamma\(Xi0-->Sigma+e-nu¯e\)/gammatotal = \(2.71+/-0.22statistical+/-0.31systematic\)×10-4. The flavor symmetric quark model calculation agrees with this result.
We report on a new measurement of the decay K L →π 0 γγ by the KTeV experiment at Fermilab. We de... more We report on a new measurement of the decay K L →π 0 γγ by the KTeV experiment at Fermilab. We determine the K L →π 0 γγ branching ratio to be (1.68±0.07±0.08)×10 -6 . Our data show the first evidence for a low-mass γγ signal as predicted by recent O(p 6 ) chiral ...
We report on two null searches, one for the spontaneous appearance of π + π - pairs, another for ... more We report on two null searches, one for the spontaneous appearance of π + π - pairs, another for a single π 0 , consistent with the decay of a long-lived neutral particle into hadrons and an unseen neutral particle. For the lowest level gluon-gluino bound state, known as the R 0 , ...
The branching ratio of the rare decay π 0 →e + e - has been measured in E799-II, a rare kaon deca... more The branching ratio of the rare decay π 0 →e + e - has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. We observed 275 candidate π 0 →e + e - events, with an expected background of 21.4±6.2 events which includes the ...
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Papers by I. Albuquerque