-
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker,
P. R. Burchat, [......],
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
S. M. Yang,
D. Yi,
S. Yoshida,
R. Zaliznyak,
C. Zhang,
W. M. Dunwoodie
Physical review D: Particles and fields 08/2006; 74(5):59901.
-
G A Alves,
S Amato,
J. C. Anjos,
J A Appel,
J. Astorga,
T. Bernard,
S. B. Bracker,
L M Cremaldi,
W. D. Dagenhart,
C L Darling, [......],
W R Ross, A F S Santoro,
M Sheaff,
M H G Souza,
C. Stoughton,
M. E. Streetman,
D J Summers,
S. F. Takach,
A. Wallace,
Z Wu
[show abstract]
[hide abstract]
ABSTRACT: Using data from Fermilab fixed-target experiment E769, we have measured particle-antiparticle production asymmetries for Lambda0 hyperons in 250 GeV/c pi+-, K+- and p -- nucleon interactions. The asymmetries are measured as functions of Feynman-x (x_F) and p_t^2 over the ranges -0.12<=x_F<=0.12 and 0<=p_t^2<=3 (GeV/c)^2 (for positive beam) and -0.12<=x_F<=0.4 and 0<=p_t^2<=10 (GeV/c)^2 (for negative beam). We find substantial asymmetries, even at x_F around zero. We also observe leading-particle-type asymmetries. These latter effects are qualitatively as expected from valence-quark content of the target and variety of projectiles studied.
04/2003;
-
E M Aitala,
S Amato,
J C Anjos,
J A Appel,
D Ashery,
S Banerjee,
I Bediaga,
G Blaylock,
S B Bracker,
P R Burchat, [......],
S Watanabe,
R Weiss-Babai,
J Wiener,
N Witchey,
E Wolin,
S M Yang,
D Yi,
S Yoshida,
R Zaliznyak,
C Zhang
[show abstract]
[hide abstract]
ABSTRACT: We study the Dalitz plot of the decay D(+)-->K(-)pi(+)pi(+) with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known Kpi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K(*)(0)(1430) to float, we obtain values consistent with those from PDG but the chi(2) per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797+/-19+/-43 MeV/c(2) and width 410+/-43+/-87 MeV/c(2). The mass and width of the K(*)(0)(1430) become 1459+/-7+/-5 MeV/c(2) and 175+/-12+/-12 MeV/c(2), respectively. Our results provide new information on the scalar sector in hadron spectroscopy.
Physical Review Letters 09/2002; 89(12):121801. · 7.37 Impact Factor
-
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker,
P. R. Burchat, [......],
S. Watanabe,
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
S. M. Yang,
D. Yi,
S. Yoshida,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: Using data from the E791 fixed-target hadroproduction experiment at Fermilab, we have studied the Cabibbo-favored but phase-space-suppressed decay D0→K-K-K+π+. We find the decay rate for this mode to be (0.54±0.16±0.08)×10-2 times that for the normalization mode D0→K-π-π+π+. We observe a clear signal for D0→φK-π+ which is consistent with producing 0.7±0.3 of the D0→K-K-K+π+ signal. In the context of simple models, we use our measurements to estimate the importance of decay amplitudes that produce extra quark-antiquark pairs from the vacuum relative to those that do not.
Phys. Rev. D. 11/2001; 64(11).
-
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker,
P. R. Burchat, [......],
S. Watanabe,
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
S.M. Yang,
D. Yi,
S. Yoshida,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: We present a study of correlations between D and
[`(D)]{\overline D}
mesons produced in 500 GeV/cπ−-nucleon interactions, based on data from experiment E791 at Fermilab. We have fully reconstructed 791 44 charm meson pairs to study correlations between the transverse and longitudinal momenta of the two D mesons and the relative production rates for different types of D meson pairs. We see slight correlations between the longitudinal momenta of the D and the
[`(D)]{\bar D}
, and significant correlations between the azimuthal angle of the D and the
[`(D)]{\bar D}
. The experimental distributions are compared to a next-to-leading-order QCD calculation and to predictions of the PYTHIA/JETSET Monte Carlo event generator. We observe less correlation between transverse momenta and different correlations between longitudinal momenta than these models predict for the default values of the model parameters. Better agreement between data and theory might be achieved by tuning the model parameters or by adding higher order perturbative terms, thus contributing to a better understanding of charm production.The relative production rates for the four sets of charm pairs,
D0[`(D)]0, D0 D-, D+[`(D)]0, D+ D-D^0{{\overline D}^0}, D^0 D^{-}, D^+{{\overline D}^0}, D^+ D^{-}
as calculated in the PYTHIA/JETSET event generator with the default parameters, agree with data as far as the relative ordering, but predict too many
D+ [`(D)]0D^+ {{\overline D}^0}
pairs and too few
D+ D-D^+ D^{-}
pairs.
EPJ direct 11/2000; 1(1):1-67.
-
Fermilab Collaboration,
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker, [......],
S. Watanabe,
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
S. M. Yang,
D. Yi,
S. Yoshida,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: We have searched for evidence of the production and decay of a neutral
bound-state pentaquark, one of a predicted doublet of states:
P0c¯s=c¯suud> and
P-c¯s=c¯sddu>. Specifically, we have
searched for the decay
P0c¯s-->K*0K-p in
data from Fermilab experiment E791, in which a 500 GeV/c
π- beam interacted with nuclear targets. We find
mass-dependent upper limits at the 90% confidence level for the ratio of
cross section times branching fraction of this decay relative to that
for the decay
Ds--->K*0K-. The upper
limits vary between 0.016 and 0.036 for
M(P0c¯s) between 2.75 and 2.91
GeV/c2, assuming a pentaquark lifetime of 0.4 ps.
Physics Letters B 01/1999; 448:303-310. · 3.95 Impact Factor
-
Fermilab Collaboration,
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker, [......],
S. Watanabe,
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
D. Yi,
S. M. Yang,
S. Yoshida,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: The form factor ratios rV=V(0)/A1(0),
r2=A2(0)/A1(0) and
r3=A3(0)/A1(0) in the decay
D+-->K¯*0l +νl,
K¯*0-->K-π+ have been
measured using data from charm hadroproduction experiment E791 at
Fermilab. From 3034 (595) signal (background) events in the muon
channel, we obtain rV=1.84+/-0.11+/-0.09,
r2=0.75+/-0.08+/-0.09 and, as a first measurement of
r3, we find 0.04+/-0.33+/-0.29. The values of the form factor
ratios rV and r2 measured for the muon channel are
combined with the values of rV and r2 that we have
measured in the electron channel. The combined E791 results for the muon
and electron channels are rV=1.87+/-0.08+/-0.07 and
r2=0.73+/-0.06+/-0.08.
Physics Letters B 10/1998; 440:435-441. · 3.95 Impact Factor
-
G. A. Alves,
S. Amato,
J. C. Anjos,
J. A. Appel,
J. Astorga,
T. Bernard,
S. B. Bracker,
L. M. Cremaldi,
W. D. Dagenhart,
C. L. Darling, [......],
W. R. Ross, A. F. S. Santoro,
M. Sheaff,
M. H. G. Souza,
C. Stoughton,
M. E. Streetman,
D. J. Summers,
S. F. Takach,
A. Wallace,
Z. Wu
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the atomic mass dependence of central Ξ- and Ξ̅ + production. It is measured using a sample of 22 459 Ξ-’s and Ξ̅ +’s produced in collisions between a 250 GeV π- beam and targets of beryllium, aluminum, copper, and tungsten. The relative cross sections are fit to the two parameter function σ0Aα, where A is the atomic mass. We measure α=0.924±0.020±0.025, for Feynman x in the range -0.09<xF<0.15.
Phys. Rev. D. 10/1997; 56(9).
-
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock,
S. B. Bracker,
P. R. Burchat, [......],
A. K. Tripathi,
S. Watanabe,
R. Weiss-Babai,
J. Wiener,
N. Witchey,
E. Wolin,
D. Yi,
S. Yoshida,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the branching ratio B(D+ ->
ρ0 l+ νl)/B(D+ ->
K*0 l+ νl) from the Fermilab charm
hadroproduction experiment E791. Based on signals of 49 +/- 17 events in
the D+ -> ρ0 e+ νe
mode and 54 +/- 18 events in the D+ -> ρ0
μ+ νμ mode, we measureB(D+
-> ρ0 e+ νe)/B(D+
-> K*0 e) νe) = 0.045 +/- 0.014
+/- 0.009,B(D+ -> ρ0 μ+
νμ)/B(D+ -> K*0
μ+ νμ) = 0.051 +/- 0.015 +/- 0.009.
Combining the results from both the electronic and muonic modes, we
obtainB(D+ -> ρ0 l+
νl)/B(D+ -> K*0 l+
νl) = 0.047 +/- 0.013. This result is compared to
theoretical predictions.
Physics Letters B 01/1997; 397:325-332. · 3.95 Impact Factor
-
E. M. Aitala,
S Amato,
J. C. Anjos,
J A Appel,
M. Aryal,
D. Ashery,
J. Astorga,
S Banerjee,
I. Bediaga,
G Blaylock, [......],
K Thorne,
A K Tripathi,
S Watanabe,
R Weiss-Babai,
J Wiener,
N Witchey,
E Wolin,
D Yi,
R Zaliznyak,
C Zhang
[show abstract]
[hide abstract]
ABSTRACT: We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used.
02/1996;
-
A. Nguyen,
E. M. Aitala,
S. Amato,
J. C. Anjos,
J. A. Appel,
M. Aryal,
D. Ashery,
S. Banerjee,
I. Bediaga,
G. Blaylock, [......],
K. Thorne,
A. K. Tripathi,
S. Watanabe,
R. Weiss,
J. Wiener,
N. Witchey,
E. Wolin,
D. Yi,
R. Zaliznyak,
C. Zhang
[show abstract]
[hide abstract]
ABSTRACT: Fermilab E791 is a high statistics charm experiment using a 500 GeV/c π− beam incident on a segmented target. We present results based on one third of the 1991‐1992 data, with particular emphasis on a search for the flavor changing neutral current decay D+→π+μ+μ−. © 1995 American Institute of Physics.
AIP Conference Proceedings. 07/1995; 338(1):777-780.
-
S. Amato,
J.C. Anjos,
I. Bediaga,
I. Costa,
J.R.T. de Mello Neto,
J.M. de Miranda, A.F.S. Santoro,
M.H.G. Souza,
G. Blaylock,
P.R. Burchat, [......],
S.B. Bracker,
J. Astroga,
R. Milburn,
A. Napier,
S. Radeztsky,
M. Sheaff,
C. Darling,
J. Slaughter,
S. Takach,
E. Wolin
[show abstract]
[hide abstract]
ABSTRACT: 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 also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.
09/1992
-
S. Amato,
J.C. Anjos,
I. Bediaga,
I. Costa,
J.R.T. de Mello Neto,
J. de Miranda, A.F.S. Santoro,
M.H.G. Souza,
G. Blaylock,
P.R. Burchat, [......],
S.B. Bracker,
J. Astorga,
R. Milburn,
A. Napier,
S. Radeztsky,
M. Sheaff,
C. Darling,
J. Slaughter,
S. Takach,
E. Wolin
[show abstract]
[hide abstract]
ABSTRACT: 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 buffered in eight large FIFO memories to allow continuous event building and continuous tape writing to a wall of 42 Exabytes at 9.6 MB/sec. The 50 terabytes of data buffered to tape is now being filtered on RISC CPUs. Preliminary results show D{sup 0} {yields} K{sup {minus}}{pi}{sup +} and D{sup +} {yields} K{sup {minus}}{pi}{pi}{sup +} decays. Rarer decays will be pursued.
05/1992
-
G.A. Alves,
J.C. Anjos,
J.R.T. de Mello Neto,
J.M. de Miranda,
H. da Motta,
A.C. dos Reis, A.F.S. Santoro,
M.H.G. Souza,
J.A. Appel,
R.L. Dixon,
H.C. Fenker,
D.R. Green,
S. Kwan,
L.H. Lueking,
P.M. Mantsch,
W.J. Spalding,
C. Stoughton,
M.E. Streetman,
S.B. Bracker,
Ga
[show abstract]
[hide abstract]
ABSTRACT: 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.
11/1990
-
Paul Karchin,
J. C. Anjos,
J. A. Appel,
A. Bean,
S. B. Bracker,
T. E. Browder,
L. M. Cremaldi,
J. R. Elliott,
C. O. Escobar,
P. Estabrooks, [......],
C. Gay,
R. Jedicke,
J. Metheny,
R. Milburn,
A. Napier,
D. Errede,
M. Sheaff,
P. Karchin,
W. Ross,
Z. Wu
Nuclear Physics B - Proceedings Supplements 04/1989; 7:60-67. · 0.88 Impact Factor
-
J. R. Raab,
J. C. Anjos,
J. A. Appel,
S. B. Bracker,
T. E. Browder,
L. M. Cremaldi,
J. R. Elliott,
C. O. Escobar,
P. Estabrooks,
M. C. Gibney, [......],
M. V. Purohit, A. F. S. Santoro,
J. S. Sidhu,
K. Sliwa,
M. D. Sokoloff,
M. H. G. Souza,
W. J. Spalding,
M. E. Streetman,
A. B. Stundia,
M. S. Witherell
[show abstract]
[hide abstract]
ABSTRACT: We have measured the lifetimes of the D0, D+, and Ds+ mesons which were produced by a high-energy photon beam incident on beryllium. Using the Fermilab Tagged Photon Spectrometer with a silicon-microstrip vertex detector we have collected 108 events from which we have extracted about 4200 D0 decays in the K-π+ and K-π+π-π+ modes, 3000 D+ into the K-π+π+ channel, and a total of 230 Ds+ into φπ+ and K¯*0K+. From an analysis of these events we have determined the lifetimes for the D0, D+, and Ds+ to be 0.422±0.008±0.010, 1.090±0.030±0.025, and 0.47±0.04±0.02 psec, respectively.
Phys. Rev. D. 04/1988; 37(9).
-
[show abstract]
[hide abstract]
ABSTRACT: We propose a natural generalization to the case of unequal constituent masses of the formula which gives the correct decay
constants for vector mesons of the quarkonium type. Within the philosophy where diquarks are used as baryonic constituents,
this allows us to evaluate the decay widths for all vector particles both mesons and diquarks to be used later in the calculation
of baryon lifetimes.
Lettere al Nuovo Cimento 05/1985; 42(2):54-58.
-
[show abstract]
[hide abstract]
ABSTRACT: The λ+
c lifetime is calculated in a quark-diquark philosophy using previous results and a number of « natural » assumptions. It is
shown that the contribution from the W-exchange dominates in this case that from the W-radiation which is estimated of the
order of ∼ 20%. The result is in good agreement with the experimental findings.
Lettere al Nuovo Cimento 12/1984; 42(2):92-96.
-
[show abstract]
[hide abstract]
ABSTRACT: We propose a model which is able to explain the main features of the
experimental data for the reaction π-p-->φφn,
starting from the assumption that two glueball resonances with
JPC=2++ are produced in this reaction. The
couplings of these glueball candidates to φφ are estimated,
and come out to be of the same strength as ordinary hadronic couplings.
Physical review D: Particles and fields 06/1984; 30:69-74.
-
[show abstract]
[hide abstract]
ABSTRACT: The decay constants of pseudoscalar mesons and scalar diquarks are calculated in an approximated way within a quark model
previously developed.
Le costanti di decadimento dei mesoni pseudoscalari e dei diquark scalari sono calcolate in modo approssimato nell’ambito
di un modello a quark sviluppato precedentemente.
В рамках модели кварков, раэвитой ранее, приближенно вычисляются постоянные распадов пседоскалярных меэонов и скалярных дикварков.
Il Nuovo Cimento A 04/1984; 81(2):485-492.
