Three events for the decay K{sup +}{yields}{pi}{sup +}{nu}{nu} have been observed in the pion momentum region below the K{sup +}{yields}{pi}{sup +}{pi}{sup 0} peak, 140<P{sub {pi}}<199 MeV/c, with an ...estimated background of 0.93{+-}0.17(stat.){sub -0.24}{sup +0.32}(syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K{sup +}{yields}{pi}{sup +}{nu}{nu})=(1.73{sub -1.05}{sup +1.15})x10{sup -10} consistent with the standard model prediction.
A compact beam stop for a rare kaon decay experiment Belz, J.; Diwan, M.; Eckhause, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1999, Letnik:
428, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We describe the development and testing of a novel beam stop for use in a rare kaon decay experiment at the Brookhaven Alternating Gradient Synchrotron. The beam stop is located inside a dipole ...spectrometer magnet in close proximity to straw drift chambers and intercepts a high-intensity neutral hadron beam. The design process, involving both Monte Carlo simulations and beam tests of alternative beam-stop shielding arrangements, had the goal of minimizing the leakage of particles from the beam stop and the resulting hit rates in detectors, while preserving maximum acceptance for events of interest. The beam tests consisted of measurements of rates in drift chambers, scintillation counter hodoscopes, a gas threshold Cherenkov counter, and a lead glass array. Measurements were also made with a set of specialized detectors which were sensitive to low-energy neutrons, photons, and charged particles. Comparisons are made between these measurements and a detailed Monte Carlo simulation.
The ability of free electrons to drift long distances at high velocities in pure liquid argon under an applied electric field has been exploited for the past forty years to implement detectors with ...increasingly large volumes for high energy physics research. In this paper, we summarize the electron attachment rate constants as a function of the external electric field for common impurities in LArTPC with data from the literature. We further provide analytical functions to parameterize the data, which are useful to compare with new measurements as well as to make extrapolations.
Evidence of massive neutrinos in the pi --> e nu decay spectrum was sought with the background pi --> mu --> e decay chain highly suppressed. Upper limits (90% C.L.) on the neutrino mixing matrix ...element |U_ei|^2 in the neutrino mass region 60--129 MeV/c^2 were set at the level of 10^-8.
To search for spontaneous conversion of muonium to antimuonium with very low background, a new signature was implemented that required the coincident detection of the decay products of the ...antimuonium atom, the energetic {ital e}{sup {minus}} and the atomic {ital e}{sup +}. No conversion events were seen, which sets an improved upper limit of 6.5{times}10{sup {minus}7} (90% C.L.) on the conversion probability. The corresponding limit on the coupling constant, using a {ital V}{minus}{ital A} form for the conversion Hamiltonian, is {ital G}{sub {ital M}{ital {bar M}}}{lt}0.16{ital G}{sub {ital F}} (90% C.L.), where {ital G}{sub {ital F}} is the Fermi coupling constant.
This paper describes in detail the acrylic target vessels used to encapsulate the target and gamma catcher regions in the Daya Bay experiment's first pair of antineutrino detectors. We give an ...overview of the design, fabrication, shipping, and installation of the acrylic target vessels and their liquid overflow tanks. The acrylic quality assurance program and vessel characterization, which measures all geometric, optical, and material properties relevant to {\nu}e detection at Daya Bay are summarized. This paper is the technical reference for the Daya Bay acrylic vessels and can provide guidance in the design and use of acrylic components in future neutrino or dark matter experiments.
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