Search Results

Advanced search parameters have been applied.
open access

Charm Photoproduction Results From the Fermilab Tagged Photon Spectrometer

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

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

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

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

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

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

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Ds+ Lifetime

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

Pion and Kaon Production of Charm and Charm-Strange States

Description: We propose an experiment to measure the properties of hadronic charm production using the Tagged Photon Spectrometer facility. We shall measure the flavor, x and A dependence of this process at the same time and in a single apparatus. In addition to collecting several times more charm than any completed or proposed hadronic experiment, we expect to have a sample of F mesons as much as two orders of magnitude more than published efforts. High statistiCs lifetime measurements of several charm sta… more
Date: November 1, 1985
Creator: Anjos, J. C. C.; Santoro, A. F. S.; Souza, M. H. G.; Appel, J. A.; Dixon, R.; Green, D. et al.
Partner: UNT Libraries Government Documents Department
open access

The K- pi+ S-wave from the D+ --> k- pi+ pi+ Decay

Description: Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K{sup -}{pi}{sup +} S-wave amplitude from the decay D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K{sup -}{pi}{sup +} system.
Date: May 1, 2009
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
Partner: UNT Libraries Government Documents Department
open access

The K- pi+ S-wave from the D+ --> K- pi+ pi+ Decay

Description: Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the K{sup -}{pi}{sup +} S-wave amplitude from the decay D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the K{sup -}{sup +} system.
Date: May 1, 2009
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Dalitz plot analysis of the D+ ---> K- pi+ pi+ decay in the FOCUS experiment

Description: Using data collected by the high energy photoproduction experiment FOCUS at Fermilab we performed a Dalitz plot analysis of the Cabibbo favored decay D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}. This study uses 53653 Dalitz-plot events with a signal fraction of {approx} 97%, and represents the highest statistics, most complete Dalitz plot analysis for this channel. Results are presented and discussed using two different formalisms. The first is a simple sum of Breit-Wigner functions with f… more
Date: May 1, 2007
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
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

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

New measurement of BR(D+ ---> rho0 mu+ nu) / BR(D+ ---> anti-K*0 mu+ nu) branching ratio

Description: Using data collected by the FOCUS experiment at Fermilab, the authors present a new measurement of the charm semileptonic branching ratio BR(D{sup +} {yields} {rho}{sup 0}{mu}{sup +}{nu})/BR(D{sup +}{yields}{bar K}*{sup 0} {mu}{sup +}{nu}). From a sample of 320 {+-} 44 and 11,372 {+-} 161 D{sup +} {yields} {rho}{sup 0}{mu}{sup +}{nu} and D{sup +} {yields} K{sup -}{pi}{sup +}{mu}{sup +}{nu} events respectively, they find BR(D{sup +} {yields} {rho}{sup 0}{mu}{sup +}{nu})/BR(D{sup +}{yields}{bar K… more
Date: November 1, 2005
Creator: Link, J. M.; Yager, P. M.; Anjos, J. C.; Bediaga, I.; Castromonte, C.; Machado, A. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Fermilab E791

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

Charm physics at Fermilab E791

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

An upper limit to the photon fraction in cosmic rays above 10**19-eV from the Pierre Auger Observatory

Description: An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies above 10{sup 19} eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger s… more
Date: June 1, 2006
Creator: Abraham, J.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allison, P. et al.
Partner: UNT Libraries Government Documents Department
open access

Study of the D0 ---> pi- pi+ pi- pi+ decay

Description: Using data from the FOCUS (E831) experiment at Fermilab, they present new measurements for the Cabbibo-suppressed decay mode D{sup 0} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}. They measure the branching ratio {Lambda}(D{sup 0} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})/{Lambda}(D{sup 0} {yields} K{sup -} {pi}{sup +}{pi}{sup -}{pi}{sup +}) = 0.0914 {+-} 0.0018 {+-} 0.0022. An amplitude analysis has been performed, a first for this channel, in order to determine the reson… more
Date: January 1, 2007
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
Partner: UNT Libraries Government Documents Department
open access

A Non-parametric approach to measuring the K- pi+ amplitudes in D+ ---> K- K+ pi+ decay

Description: Using a large sample of D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decays collected by the FOCUS photoproduction experiment at Fermilab, we present the first non-parametric analysis of the K{sup -}{pi}{sup +} amplitudes in D{sup +} {yields} K{sup -}K{sup +}{pi}{sup +} decay. The technique is similar to the technique used for our non-parametric measurements of the D{sup +} {yields} {bar K}*{sup 0} e{sup +}{nu} form factors. Although these results are in rough agreement with those of E687, we … more
Date: December 1, 2006
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Search for Lambda+(c) ---> p K+ pi- and D+(s) ---> K+ K+ pi- using genetic programming event selection

Description: The authors apply a genetic programming technique to search for the doubly Cabibbo suppressed decays {Lambda}{sub c}{sup +} {yields} pK{sup +} {pi}{sup -} and D{sub s}{sup +} {yields} K{sup +}K{sup +}{pi}{sup -}. They normalize these decays to their Cabibbo favored partners and find BR({Lambda}{sub c}{sup +} {yields} pK{sup +}{pi}{sup -})/BR({Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +}) = (0.05 {+-} 0.26 {+-} 0.02)% and BR(D{sub s}{sup +} {yields} K{sup +}K{sup +}{pi}{sup -})/BR(D{sub s… more
Date: July 1, 2005
Creator: Link, J. M.; Yager, P. M.; Anjos, J. C.; Bediaga, I.; Castromonte, C.; Machado, A. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Anisotropy studies around the Galactic Centre at EeV energies with the Auger Observatory

Description: Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicti… more
Date: July 1, 2006
Creator: Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allison, P.; Alvarez, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Hadroproduction of charm at Fermilab E769

Description: 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.
Partner: UNT Libraries Government Documents Department
open access

Study of the D0 ---> K+ K- pi+ pi-

Description: Using data from the FOCUS (E831) experiment at Fermilab, the authors present a new measurement for the Cabibbo-suppressed decay mode D{sup 0} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}. They measure: {Lambda}(D{sup 0} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup +}) = 0.0295 {+-} 0.0011 {+-} 0.0008. An amplitude analysis has been performed in order to determine the resonant substructure of this decay mode. The dominant c… more
Date: November 1, 2004
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Gobel, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the doubly Cabibbo suppressed decay D0 ---> K+ pi- and a search for charm mixing

Description: The authors present an analysis of the decay D{sup 0} {yields} K{sup +}{pi}{sup -} based on FOCUS data. From a sample of 234 signal events, they find a branching ratio of {Lambda}(D{sup 0} {yields} K{sup +}{pi}{sup -})/{Lambda}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (0.429{sub -0.061}{sup +0-.063} {+-} 0.027)% under the assumptions of no mixing and no CP violation. Allowing for CP violation, the find a branching ratio of (0.435{sub -0.061}{sup +0.063} {+-} 0.028)% and a CP asymmetry of 0.178{… more
Date: December 1, 2004
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Gobel, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Hadronic mass spectrum analysis of D+ ---> K- pi+ mu+ nu decay and measurement of the K*(892)0 mass and width

Description: We present a K{pi} mass spectrum analysis of the four-body semileptonic charm decay D{sup +} {yields} K{sup -}{pi}{sup +}{mu}{sup +}{nu} in the range of 0.65 GeV/c{sup 2} < m{sub K{pi}} < 1.5 GeV/c{sup 2}. We observe a non-resonant contribution of 5.30 {+-} 0.74{sub -0.51}{sup +0.99}% with respect to the total D{sup +} {yields} K{sup -} {pi}{sup +}{mu}{sup +}{nu} decay. For the K*(892){sup 0} resonance, we obtain a mass of 895.41 {+-} 0.32{sub -0.36}{sup +0.35} NeV/c{sup 2}, a width of 47… more
Date: March 1, 2005
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Gobel, C. et al.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen