Showing papers by "D. P. Benjamin published in 1993"
TL;DR: In this paper, the authors report the full reconstruction of mesons through the decay chain, using data obtained at the Collider Detector at Fermilab in 2.8 TeV.
Abstract: We report the full reconstruction of ${\mathrm{\ensuremath{\chi}}}_{\mathit{c}}$ mesons through the decay chain ${\mathrm{\ensuremath{\chi}}}_{\mathit{c}}$\ensuremath{\rightarrow}J/\ensuremath{\psi} \ensuremath{\gamma}, J/\ensuremath{\psi}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}$, using data obtained at the Collider Detector at Fermilab in 2.6\ifmmode\pm\else\textpm\fi{}0.2 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV. This exclusive ${\mathrm{\ensuremath{\chi}}}_{\mathit{c}}$ sample is used to measure the ${\mathrm{\ensuremath{\chi}}}_{\mathit{c}}$-meson production cross section times branching fractions. We obtain \ensuremath{\sigma}\ifmmode\times\else\texttimes\fi{}B=3.2\ifmmode\pm\else\textpm\fi{}0.4(stat${)}_{\mathrm{\ensuremath{-}}1.1}^{+1.2}$(syst) nb for ${\mathrm{\ensuremath{\chi}}}_{\mathit{c}}$ mesons decaying to J/\ensuremath{\psi} with ${\mathit{p}}_{\mathit{T}}$g6.0 GeV/c and pseudorapidity \ensuremath{\Vert}\ensuremath{\eta}\ensuremath{\Vert}0.5. From this and the inclusive J/\ensuremath{\psi} cross section we calculate the inclusive b-quark cross section to be 12.0\ifmmode\pm\else\textpm\fi{}4.5 \ensuremath{\mu}b for ${\mathit{p}}_{\mathit{T}}^{\mathit{b}}$g8.5 GeV/c and \ensuremath{\Vert}${\mathit{y}}^{\mathit{b}}$\ensuremath{\Vert}1.
59 citations
TL;DR: In this article, the authors presented a measurement of the [ital b]-quark cross section in 1.8 TeV [ital p]-[ital [bar p] collisions recorded with the Collider Detector at Fermilab using muonic quark decays.
Abstract: We present a measurement of the [ital b]-quark cross section in 1.8 TeV [ital p]-[ital [bar p]] collisions recorded with the Collider Detector at Fermilab using muonic [ital b]-quark decays. In the central rapidity region ([vert bar][ital y][sup [ital b]][vert bar][lt]1.0), the cross section is 295[plus minus]21[plus minus]75 nb (59[plus minus]14[plus minus]15 nb) for [ital p][sub [ital T]][sup [ital b]][gt]21 GeV/[ital c] (29 GeV/[ital c]). Comparisons are made to previous measurements and next-to-leading order QCD calculations.
48 citations
TL;DR: In this paper, the authors present a measurement of jet shapes in [ital [bar p]p] collisions at [radical][ital s] = 1.8 TeV at the Fermilab Tevatron using the Collider Detector.
Abstract: We present a measurement of jet shapes in [ital [bar p]p] collisions at [radical][ital s] =1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab (CDF). Qualitative agreement is seen with the predictions of recent next-to-leading [[ital O]([alpha][sub [ital s]][sup 3])] calculations and with leading logarithm QCD based Monte Carlo simulations. The dependence of the jet shape on transverse energy is studied.
32 citations
TL;DR: The average lifetime of a b-hadron was measured using a high statistics sample of {ital B} {r_arrow} {ital J}/{psi}{Chi} decays recorded with the Collider Detector at Fermilab as discussed by the authors.
Abstract: The average b-hadron lifetime has been measured using a high statistics sample of {ital B} {r_arrow} {ital J}/{psi}{Chi} decays recorded with the Collider Detector at Fermilab We use a sample with an integrated luminosity of {approx} 90 {ital pb}{sup -1} recorded during the 1994-95 running period The decay vertices of {approx} 62656 inclusive {ital J}/{psi} {r_arrow} {mu}{sup +}{mu}{sup -} candidates have been reconstructed using information from a silicon vertex-detector The measured {ital B}lifetime, which is the average over all b-hadrons produced in {ital p}{ital {anti p}} collisions at {radical}s = 18 TeV weighted by their branching ratios into {ital J}/{psi}, is 1524 {+-} 0015 ({ital stat}){sup +0035}{sub -0026} ({ital sys}) ps The precision of this measurement is significantly improved compared to the inclusive lifetime measurement published previously using {approx} 10 {ital pb}{sup -1}
22 citations
TL;DR: Model-independent limits on the production of heavy particles decaying into two jets are presented and a limit on quark compositeness of ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}$g1.3 TeV is obtained.
Abstract: The dijet invariant mass distribution has been measured in the region between 140 and 1000 GeV/${\mathit{c}}^{2}$, in 1.8 TeV p p\ifmmode\bar\else\textasciimacron\fi{} collisions. Data collected with the Collider Detector at Fermilab show agreement with QCD calculations. A limit on quark compositeness of ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}$g1.3 TeV is obtained. Axigluons with masses between 240 and 640 GeV/${\mathit{c}}^{2}$ are excluded at 95% C.L. if we assume ten open decay channels. Model-independent limits on the production of heavy particles decaying into two jets are also presented.
21 citations
TL;DR: Measurements from events with two isolated prompt photons in collisions at [radical][ital s] =1.8 TeV show differential cross section, measured as a function of transverse momentum, is about 3 times what next-to-leading-order QCD calculations predict.
Abstract: We present measurements from events with two isolated prompt photons in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV. The differential cross section, measured as a function of transverse momentum (${\mathit{P}}_{\mathit{T}}$) of each photon, is about 3 times what next-to-leading-order QCD calculations predict. The cross section for photons with ${\mathit{P}}_{\mathit{T}}$ in the range 10--19 GeV is 86\ifmmode\pm\else\textpm\fi{}27(stat${)}_{\mathrm{\ensuremath{-}}23}^{+32}$(syst) pb. We also study the correlation between the two photons in both azimuthal angle and ${\mathit{P}}_{\mathit{T}}$. The magnitude of the vector sum of the transverse momenta of both photons, ${\mathit{K}}_{\mathit{T}}$=\ensuremath{\Vert}${\mathbf{P}}_{\mathit{T}1}$+${\mathbf{P}}_{\mathit{T}2}$\ensuremath{\Vert}, has a mean value of 〈${\mathit{K}}_{\mathit{T}}$〉=5.1\ifmmode\pm\else\textpm\fi{}1.1 GeV.
19 citations
TL;DR: In this paper, the mass of the [ital B][sub [ital s]][sup 0] meson was determined to be 5383.3[plus minus]4.5(stat)[plusminus]5.0(syst) MeV/[ital c][sup 2].
Abstract: This Letter reports the observation and mass measurement of fully reconstructed [ital B][sub [ital s]][sup 0] mesons through the decay chain [ital B][sub [ital s]][sup 0][r arrow][ital J]/[psi] [psi], [ital J]/[psi][r arrow][mu][sup +][mu][sup [minus]], [phi][r arrow][ital K][sup +][ital K[minus]] using data obtained at the Collider Detector at Fermilab in [ital [bar p]p] collisions at [radical][ital s] =1.8 TeV. A signal of 14.0[plus minus]4.7 events is observed. Comparison of the [ital B][sub [ital s]][sup 0] signal with the kinematically similar decays [ital B][sup +][r arrow][ital J]/[psi] [ital K][sup +] and [ital B][sup 0][r arrow][ital J]/[psi] K[sup *](892)[sup 0] is presented. The mass of the [ital B][sub [ital s]][sup 0] meson is determined to be 5383.3[plus minus]4.5(stat)[plus minus]5.0(syst) MeV/[ital c][sup 2].
15 citations
TL;DR: In this paper, the authors measured the production cross section times the branching ratio for [ital W][r arrow][ital l][nu], [ital l]=[ital e],[mu] decays as a function of the associated jet multiplicity.
Abstract: The [ital W] production cross section times the branching ratio for [ital W][r arrow][ital l][nu], [ital l]=[ital e],[mu] decays has been measured as a function of the associated jet multiplicity. The data have been recorded at the Collider Detector at Fermilab during the 1988--89 run. A recent leading order QCD calculation agrees well with the data up to a jet multiplicity of 4.
10 citations
TL;DR: Data taken with the Collider Detector at Fermilab during the 1988-1989 run of the Tevatron are used to measure the distribution of the center-of-mass angle between isolated prompt photons and the beam direction.
Abstract: Data taken with the Collider Detector at Fermilab (CDF) during the 1988--1989 run of the Tevatron are used to measure the distribution of the center-of-mass (rest frame of the initial state partons) angle between isolated prompt photons and the beam direction. The shape of the angular distribution for photon-jet events is found to be significantly different from that observed in dijet data. The QCD predictions show qualitative agreement with the observed prompt photon angular distribution.
4 citations
TL;DR: In this article, the authors search for the $b$-flavored baryon decay in collisions at 1.8$ TeV with the Collider Detector at Fermilab (CDF).
Abstract: We have searched for the $b$-flavored baryon decay ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\frac{J}{\ensuremath{\psi}}{\ensuremath{\Lambda}}^{0}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV with the Collider Detector at Fermilab (CDF). In the $\frac{J}{\ensuremath{\psi}}{\ensuremath{\Lambda}}^{0}$ invariant-mass distribution we observe a flat distribution and a small number of events, consistent with no signal. Using the $b$-quark cross section measured by the CDF we put an upper limit on the $b\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{b}$ production fraction times the branching ratio $F({\ensuremath{\Lambda}}_{b})B({\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\frac{J}{\ensuremath{\psi}}{\ensuremath{\Lambda}}^{0})$ of 0.50\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ at 90% confidence level.
3 citations
Journal Article•