-
T. Aaltonen,
A. Abulencia,
J. Adelman,
T. Affolder,
T. Akimoto,
M. Albrow,
S. Amerio,
D. Amidei,
A. Anastassov,
K. Anikeev, [......],
G. Yu,
I. Yu,
S. Yu,
J. Yun,
L. Zanello,
A. Zanetti,
I. Zaw,
X. Zhang,
J. Zhou,
S. Zucchelli
Physical Review D. 04/2008; 77(7):1-24.
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
S. R. Amendolia,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
Physical review D: Particles and fields 05/2003; 67(11):119901.
-
D. Acosta,
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the flavor-changing neutral current decay
Bs-->μ+μ-φ in ppbar
collisions at (s)=1.8 TeV, using 91 pb-1 of data collected at
the Collider Detector at Fermilab (CDF). We find two candidate events
for this decay, which are consistent with the background estimate of one
event, and set an upper limit on the branching fraction of
B(Bs-->μ+μ-φ)<6.7×10-5
at a 95% confidence level. This is the first limit on the branching
fraction of this decay.
Physical review D: Particles and fields 05/2002; 65(11):111101.
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari,
T. Arisawa, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: The growth and development of “charged particle jets” produced in proton-antiproton collisions at 1.8 TeV are studied over a transverse momentum range from 0.5 GeV/c to 50 GeV/c. A variety of leading (highest transverse momentum) charged jet observables are compared with the QCD Monte Carlo models HERWIG, ISAJET, and PYTHIA. The models describe fairly well the multiplicity distribution of charged particles within the leading charged jet, the size of the leading charged jet, the radial distribution of charged particles and transverse momentum around the leading charged jet direction, and the momentum distribution of charged particles within the leading charged jet. The direction of the leading “charged particle jet” in each event is used to define three regions of η-φ space. The “toward” region contains the leading “charged particle jet,” while the “away” region, on the average, contains the away-side jet. The “transverse” region is perpendicular to the plane of the hard 2-to-2 scattering and is very sensitive to the “underlying event” component of the QCD Monte Carlo models. HERWIG, ISAJET, and PYTHIA with their default parameters do not describe correctly all the properties of the “transverse” region.
Phys. Rev. D. 04/2002; 65(9).
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari,
T. Arisawa, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We have searched for evidence of physics beyond the standard model in events that include an energetic photon and an energetic b-quark jet, produced in 85pb-1 of p̅ p collisions at 1.8 TeV at the Tevatron Collider at Fermilab. This signature, containing at least one gauge boson and a third-generation quark, could arise in the production and decay of a pair of new particles, such as those predicted by supersymmetry, leading to a production rate exceeding standard model predictions. We also search these events for anomalous production of missing transverse energy, additional jets and leptons (e, μ and τ), and additional b quarks. We find no evidence for any anomalous production of γb or γb+X events. We present limits on two supersymmetric models: a model where the photon is produced in the decay χ̃20→γχ̃10, and a model where the photon is produced in the neutralino decay into the gravitino LSP, χ̃10→γG̃. We also present our limits in a model-independent form and test methods of applying model-independent limits.
Phys. Rev. D. 02/2002; 65(5).
-
D. Acosta,
T. Affolder,
H. Akimoto,
A. Akopian,
P. Amaral,
D. Ambrose,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a detailed examination of the heavy flavor content of the W+jet data sample collected with the Collider Detector at Fermilab during the 1992–1995 collider run at the Fermilab Tevatron. Jets containing heavy flavor quarks are selected via the identification of secondary vertices or semileptonic decays of b and c quarks. There is generally good agreement between the rates of secondary vertices and soft leptons in the data and in the standard model simulation including single and pair production of top quarks. An exception is the number of events in which a single jet has both a soft lepton and a secondary vertex tag. In W+2,3 jet data, we find 13 such events where we expected 4.4±0.6 events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.
Phys. Rev. D. 02/2002; 65(5).
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
G P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We have performed a search for gluinos (g) and scalar quarks (q) in a data sample of 84 pb(-1) of pp collisions at square root[s] = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and three or more jets, a characteristic signature in R-parity-conserving supersymmetric models. The analysis has been performed "blind," in that the inspection of the signal region is made only after the predictions from standard model backgrounds have been calculated. Comparing the data with predictions of constrained supersymmetric models, we exclude gluino masses below 195 GeV/c2 (95% C.L.), independent of the squark mass. For the case m(q) approximately m(g), gluino masses below 300 GeV/c2 are excluded.
Physical Review Letters 02/2002; 88(4):041801. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present the first general search for new heavy particles, X, which decay via X --> WZ0 --> e(nu)+jj as a function of M(X) and Gamma(X) in pp collisions at square root[s] = 1.8 TeV. No evidence is found for production of X in 110 pb(-1) of data collected by the Collider Detector at Fermilab. General cross section limits are set at the 95% C.L. as a function of mass and width of the new particle. The results are further interpreted as mass limits on the production of new heavy charged vector bosons which decay via W' --> WZ0 in an extended gauge model as a function of the width, Gamma(W'), and mixing factor between the W' and the standard model W bosons.
Physical Review Letters 02/2002; 88(7):071806. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report a study of the decays B0 --> J/psiK(*)0pi(+)pi(-), which involve the creation of a uu or dd quark pair in addition to a b -->c(cs) decay. The data sample consists of 110 pb(-1) of pp collisions at square root[s] = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching fractions to be B(B0 --> J/psiK(*0)pi(+)pi(-)) = (6.6 +/- 1.9 +/- 1.1)x10(-4) and B(B0 --> J/psiK0pi(+)pi(-)) = (10.3 +/- 3.3 +/- 1.5)x10(-4). Evidence is seen for contributions from psi(2S)K(*)0, J/psiK0rho(0), J/psiK(*+)pi(-), and J/psiK1(1270).
Physical Review Letters 02/2002; 88(7):071801. · 7.37 Impact Factor
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
S. R. Amendolia,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
Physical review D: Particles and fields 01/2002; 65(3):39902.
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report a measurement of the strong coupling constant, alpha(s)(MZ), extracted from inclusive jet production in pp collisions at square root[s] = 1800 GeV. The QCD prediction for the evolution of alpha(s) with jet transverse energy ET is tested over the range 40<ET<450 GeV using ET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of alpha(s) at the mass of the Z0 boson averaged over the range 40<ET<250 GeV is found to be alpha(s)(MZ) = 0.1178+/-0.0001(stat)+0.0081(-0.0095)(expt. syst). The associated theoretical uncertainties are mainly due to the choice of renormalization scale ((+6%)(-4%)) and input parton distribution functions (5%).
Physical Review Letters 01/2002; 88(4):042001. · 7.37 Impact Factor
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari,
T. Arisawa, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon + muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV pp̅ collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to the Compton scattering process cg⃗cγ, with the final-state charm quark producing a muon. The cross section for events with a photon transverse momentum between 12 and 40 GeV/c is measured to be 46.8±6.3±7.5 pb, which is two standard deviations below the most recent theoretical calculation. A significant fraction of the events in the sample contain a final-state bottom quark. The ratio of charm to bottom production is measured to be 2.4±1.2, in good agreement with QCD models.
Phys. Rev. D. 12/2001; 65(1).
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of diffractive J/psi(--> mu+mu-) production in pp collisions at root square[s] = 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p(mu)T>2 GeV/c within the pseudorapidity region /eta/ < 1.0, the ratio of diffractive to total J/psi production rates is found to be R(J/psi) = [1.45 +/- 0.25]%. The ratio R(J/psi)(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio R(jj)(x) for diffractive dijet production, we extract a value of 0.59 +/- 0.15 for the gluon fraction of the diffractive structure function of the proton.
Physical Review Letters 12/2001; 87(24):241802. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present results of the first search for like-sign dilepton ( e(+/-)e(+/-), e(+/-)mu(+/-), mu(+/-)mu(+/-)) events associated with multijets and large missing energy using 106 pb(-1) of data in pp macro collisions at square root of s = 1.8 TeV collected during 1992-1995 by the CDF experiment. Finding no events that pass our selection, we examine pair production of gluinos (tilde g) and squarks (tilde q) in a constrained framework of the minimal supersymmetric standard model. At tan beta = 2 and mu = -800 GeV/c(2), we set 95% confidence level limits of M(tilde g)>221 GeV/c(2) for M(tilde g) approximately M(tilde q), and M(tilde q)>168 GeV/c(2) for M(tilde q)>M(tilde g), both with small variation as a function of mu.
Physical Review Letters 12/2001; 87(25):251803. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a measurement of the mean charged-particle multiplicity of jets in dijet events with dijet masses in the range 80-630 GeV/c(2), produced at the Tevatron in pp collisions with square root (s) = 1.8 TeV and recorded by the Collider Detector at Fermilab. The data are fit to perturbative-QCD calculations carried out in the framework of the modified leading log approximation and the hypothesis of local parton-hadron duality. The fit yields values for two parameters in that framework: the ratio of parton multiplicities in gluon and quark jets, r identical withN(g-jet)(partons)/N(q-jet)(partons) = 1.7+/-0.3, and the ratio of the number of charged hadrons to the number of partons in a jet, K(charged)(LPHD) identical with N(charged)(hadrons)/N(partons) = 0.57+/-0.11.
Physical Review Letters 12/2001; 87(21):211804. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present searches for quark-lepton compositeness and a heavy W' boson at high electron-neutrino transverse mass. We use approximately 110 pb(-1) of data collected in p p macro collisions at square root of [s] = 1.8 TeV by the CDF Collaboration during 1992-1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Lambda, the ratio of partial cross sections sigma(W'-->enu)/sigma(W-->enu), and the mass of a W' boson with standard model couplings. We exclude Lambda<2.81 TeV and a W' boson with mass below 754 GeV/c(2) at the 95% confidence level. Combining with our previously published limit obtained using the muon channel, we exclude a W' boson with mass below 786 GeV/c(2) at the 95% confidence level.
Physical Review Letters 12/2001; 87(23):231803. · 7.37 Impact Factor
-
T. Affolder,
H. Akimoto,
A. Akopian,
M. G. Albrow,
P. Amaral,
D. Amidei,
K. Anikeev,
J. Antos,
G. Apollinari,
T. Arisawa, [......],
P. Yeh,
J. Yoh,
C. Yosef,
T. Yoshida,
I. Yu,
S. Yu,
Z. Yu,
A. Zanetti,
F. Zetti,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 pb-1 of pp̅ collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both pp̅ →γγ+X and pp̅ →γγ+W/Z. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale √F in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for H⃗γγ. Finally, we set a lower limit on the mass of a “bosophilic” Higgs boson (e.g., one which couples only to γ, W, and Z bosons with standard model couplings) of 82 GeV/c2 at 95% confidence level.
Phys. Rev. D. 10/2001; 64(9).
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
S R Amendolia,
D Amidei,
K Anikeev,
J Antos,
G Apollinari, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We have measured the p(T) distribution of top quarks that are pair produced in pp collisions at sqrt[s] = 1.8 TeV using a sample of tt decays in which we observe a single high- p(T) charged lepton, a neutrino, and four or more jets. We use a likelihood technique that corrects for the experimental bias introduced due to event reconstruction and detector resolution effects. The observed distribution is consistent with the standard model prediction. We use these data to place limits on the production of high- p(T) top quarks suggested in some models of anomalous top quark pair production.
Physical Review Letters 10/2001; 87(10):102001. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.
Physical Review Letters 10/2001; 87(14):141802. · 7.37 Impact Factor
-
T Affolder,
H Akimoto,
A Akopian,
M G Albrow,
P Amaral,
D Amidei,
K Anikeev,
J Antos,
G Apollinari,
T Arisawa, [......],
P Yeh,
J Yoh,
C Yosef,
T Yoshida,
I Yu,
S Yu,
Z Yu,
A Zanetti,
F Zetti,
S Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A(FB), and production cross section d sigma/dM for e(+)e(-) pairs with mass M(ee)>40 GeV/c(2). The data sample consists of 108 pb(-1) of pp macro collisions at square root of s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and d sigma/dM are compared with the predictions of the standard model and a model with an extra Z' gauge boson.
Physical Review Letters 09/2001; 87(13):131802. · 7.37 Impact Factor
