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in creator/contributor: "Bracker, S. B."

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A Search for Flavour Changing Neutral Current Processes in Decays of Charmed Mesons

Neutral current interactions are known from studies of K meson decays to conserve flavor to a high precision. Although flavor changing neutral currents (FCNC) are forbidden in the Weinberg-Salam model, many extensions of the Standard Model allow such processes. We present preliminary upper limits on FCNC-mediated decays of charmed particles, namely D/sup 0/ ..-->.. e/sup +/e/sup -/, D/sup 0/ ..-->.. ..mu../sup +/..mu../sup -/, D/sup 0/ ..-->.. ..mu..e and D/sup +/ ..-->.. ..pi../sup +/..mu..e.

Date: September 1, 1987

Creator: Anjos, J. C.; Appel, J. A.; Bracker, S. B.; Browder, T. E.; Cremaldi, L. M.; Elliott, J. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A Study of the Semileptonic Decay Mode D/Sup 0/. -->. K/Sup -/E/Sup +/Nu/Sub E/

We present an analysis of the exclusive semileptonic decay mode D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/. We have measured the ratio of decay rates GAMMA(D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/)/GAMMA(D/sup 0/ ..-->.. K/sup -/..pi../sup +/). After correcting for the reconstruction efficiencies and subtracting the contribution from other decay modes we have found the ratio to be equal to 0.77 +- 0.12(stat) +- 0.13(syst).

Date: September 1, 1987

Creator: Anjos, J. C.; Appel, J. A.; Bracker, S. B.; Browder, T. E.; Cremaldi, L. M.; Elliott, J. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hadroproduction of charm at Fermilab E769

Experiment E769 at Fermilab obtained charm hadroproduction data during the 1987-88 Fixed Target running period with a 250 GeV hadron beam incident on thin target foils of Be, Al, Cu, and W. From an analysis of 25% of the recorded 400M trigger sample we have explored the Feynman x, p{sub t}{sup 2} and the atomic number dependence of charm quark production using samples of D{sup +} and D{sup 0} mesons. 7 refs., 4 figs.

Date: November 15, 1990

Creator: Alves, G. A.; Anjos, J. C.; de Mello Neto, J. R. T.; de Miranda, J. M.; da Motta, H.; dos Reis, A. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Charm Photoproduction Results From the Fermilab Tagged Photon Spectrometer

We report results from a preliminary analysis of approximately 30 million reconstructed events (30% of the data) from E-691, a charm photoproduction experiment conducted at the Fermilab Tagged Photon Laboratory in 1985. We present ratios of antiparticles to particles, p/sub T//sup 2/ distributions, x/sub F/ distributions, the total charm production cross-section and its energy dependence and the fraction of D/sup 0/s from D*s.

Date: February 1, 1987

Creator: Anjos, J. C.; Appel, J. A.; Bracker, S. B.; Browder, T. E.; Cremaldi, L. M.; Elliott, J. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Results on charm production from E791, a high statistics charm hadroproduction experiment at Fermilab

Fermilab experiment E791 collected a large sample of charm events to study several aspects of charm physics. Many topics on production and decay of charm particles can be covered with this data set. This talk will concentrate on the production asymmetry of charm mesons.

Date: May 1994

Creator: Banerjee, S.; Appel, J. A.; Aitala, E. M.; Amato, S.; Anjos, J. C.; Bediaga, I. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurement of the Ds+ Lifetime

We have observed 99 decays of the charmed strange meson, the D/sub s//sup +/ (formerly called the F/sup +/), into the phi..pi../sup +/ (61) and antiK*/sup 0/K/sup +/ (38) final states in the Fermilab photoproduction experiment E-691. We determine the lifetime to be (.48/sub -.05//sup +.06/ +- .02) x 10/sup -12/s, Using our reported measurement of the D/sup 0/ lifetime, we calculate the ratio tau(D/sub s//sup +/)/tau(D/sup 0/) = (1.10 +- .15 +- .04).

Date: February 1, 1987

Creator: Anjos, J. C.; Appel, J. A.; Bracker, S. B.; Browder, T. E.; Cremaldi, L. M.; Elliott, J. R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Model independent measurement of S-wave K- pi+ systems using D+ ---> K pi pi decays from Fermilab E791

A model-independent partial-wave analysis of the S-wave component of the K{pi} system from decays of D{sup +} mesons to the three-body K{sup -}{pi}{sup +}{pi}{sup +} final state is described. Data come from the Fermilab E791 experiment. Amplitude measurements are made independently for ranges of K{sup -}{pi}{sup +} invariant mass, and results are obtained below 825 MeV/c{sup 2}, where previous measurements exist only in two mass bins. This method of parametrizing a three-body decay amplitude re… more

Date: July 1, 2005

Creator: Aitala, E. M.; Amato, S.; Anjos, J. C.; Appel, J. A.; Ashery, D.; Banerjee, S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fermilab E791

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab`s Tagged Photon Laboratory. Over 20 billionevents were recorded through a loose transverse energy trigger and written to 8mm tape in the 1991--92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysis on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We… more

Date: October 1, 1992

Creator: Amato, S.; Anjos, J. C.; Bediaga, I.; Costa, I.; de Mello Neto, J. R. T.; de Miranda, J. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Charm physics at Fermilab E791

Experiment 791 at Fermilab`s Tagged Photon Laboratory has just accumulated a high statistics charm sample by recording 20 billion events on 24000 8mm tapes. A 500 GeV/c {pi}{sup {minus}} beam was used with a fixed target and a magnetic spectrometer which now includes 23 silicon microstrip planes for vertex reconstruction. A new data acquisition system read out 9000 events/sec during the part of the Tevatron cycle that delivered beam. Digitization and readout took 50 {mu}S per event. Data was bu… more

Date: May 26, 1992

Creator: Amato, S.; Anjos, J. C.; Bediaga, I.; Costa, I.; de Mello Neto, J. R. T.; de Miranda, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department