Evidence for the decay Σ+ → pμ+μ PARK, H. K; BURNSTEIN, R. A; GIDAL, G ...
Physical review letters,
01/2005, Volume:
94, Issue:
2
Journal Article
Peer reviewed
Open access
We report the first evidence for the decay {Sigma}{sup +} {yields} p{mu}{sup +}{mu}{sup -} from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ...ratio is {Beta}({Sigma}{sup +} {yields} p{mu}{sup +}{mu}{sup -}) = 8.6{sub -5.4}{sup +6.6}(stat) {+-} 5.5(syst) x 10{sup -8}. The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, {Sigma}{sup +} {yields} pP{sup 0},P{sup 0} {yields} {mu}{sup +}{mu}{sup -} with a P{sup 0} mass of 214.3 {+-} 0.5 MeV/c{sup 2} and branching ratio {Beta}({Sigma}{sup +} {yields} pP{sup 0}, P{sup 0} {yields} {mu}{sup +}{mu}{sup -}) = 3.1{sub -1.9}{sup +2.4}(stat) {+-} 1.5(syst) x 10{sup -8}.
What Can Be Done to Stop the Decline? Lederman, Leon M.
Science (American Association for the Advancement of Science),
07/2005, Volume:
309, Issue:
5731
Journal Article
The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular
CP violation in
Ξ
and
Λ
hyperon decays with a sensitivity of
...10
-
4
. Intense charged secondary beams were produced by 800
GeV/
c protons and momentum selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in 12 months of data-taking.
: We begin with the absurdity of ninth‐grade biology to bewail the fate of high school science education as one component of a wholly inadequate K‐12 education. Our proposal for a coherent ...physics‐chemistry‐biology core curriculum for all high school students leads naturally to seeking the connections between the sciences, the sciences and mathematics, and indeed to the social sciences and the humanities. Our goal is literacy—scientific and humanistic—as the sensible goal for a 21st century high school graduate.
Using data collected with the HyperCP (E871) spectrometer during the 1997 fixed-target run at Fermilab, we report the first observation of the decay K--->pi(-)mu(+)mu(-) and new measurements of the ...branching ratios for K+/--->pi(+/-)mu(+)mu(-). By combining the branching ratios for the decays K+-->pi(+)mu(+)mu(-) and K--->pi(-)mu(+)mu(-), we measure Gamma(K+/--->pi(+/-)mu(+)mu(-))/Gamma(K+/--->all) = (9.8+/-1.0+/-0.5)x10(-8). The CP asymmetry between the rates of the two decay modes is Gamma(K+-->pi(+)mu(+)mu(-))-Gamma(K--->pi(-)mu(+)mu(-))/Gamma(K+-->pi(+)mu(+)mu(-))+Gamma(K--->pi(-)mu(+)mu(-)) = -0.02+/-0.11+/-0.04.
Test-based accountability system is being controlled by people who may know how to develop standardized achievement tests but know very little about the institutional realities of accountability and ...even less about how to improve instruction in schools. A novel way to increase student engagement and counter the pressures of high-stakes testing is proposed.
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