Showing papers by "M. J. Shochet published in 2002"
TL;DR: The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production, as well as on the Upsilonian polarization in p p macro collisions at square root of s = 1.8 TeV.
Abstract: We report on measurements of the Y(1S), Y(2S), and Y(3S) differential cross sections (d(2)sigma/dp(T)dy)(\y\ collisions at roots = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Y-->mu(+)mu(-) . The measured angular distribution of the muons in the Y(1S) rest frame is consistent with unpolarized meson production.
78 citations
TL;DR: In this paper, a search for gluinos and scalar quarks in a data sample of 84 pb(-1) of p (p) over bar collisions at roots = 1.8 TeV was performed.
Abstract: We have performed a search for gluinos ((g) over tilde) and scalar quarks ((q) over tilde) in a data sample of 84 pb(-1) of p (p) over bar collisions at roots = 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/c(2) (95% C.L.), independent of the squark mass. For the case m((q) over bar) approximate to m((g) over tilde), gluino masses below 300 GeV/c(2) are excluded.
70 citations
TL;DR: In this paper, the authors measured the total cross section and differential cross section of the Formula Presented meson using the CDF detector, and the measured differential cross-section is substantially larger than typical QCD predictions calculated to next-to-leading order.
Abstract: We present measurements of the [Formula Presented] meson total cross section and differential cross section [Formula Presented] The measurements use a [Formula Presented] [Formula Presented] sample of [Formula Presented] collisions at [Formula Presented] collected by the CDF detector. Charged B meson candidates are reconstructed through the decay [Formula Presented] with [Formula Presented] The total cross section, measured in the central rapidity region [Formula Presented] for [Formula Presented] is [Formula Presented] The measured differential cross section is substantially larger than typical QCD predictions calculated to next-to-leading order. © 2002 The American Physical Society.
67 citations
TL;DR: The QCD prediction for the evolution of alpha(s) with jet transverse energy ET is tested over the range 40
Abstract: We report a measurement of the strong coupling constant, ${\ensuremath{\alpha}}_{s}({M}_{Z})$, extracted from inclusive jet production in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1800\mathrm{GeV}$ The QCD prediction for the evolution of ${\ensuremath{\alpha}}_{s}$ with jet transverse energy ${E}_{T}$ is tested over the range $40l{E}_{T}l450\mathrm{GeV}$ using ${E}_{T}$ for the renormalization scale The data show good agreement with QCD in the region below 250 GeV The value of ${\ensuremath{\alpha}}_{s}$ at the mass of the ${Z}^{0}$ boson averaged over the range $40l{E}_{T}l250\mathrm{GeV}$ is found to be ${\ensuremath{\alpha}}_{s}({M}_{Z})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}01178\ifmmode\pm\else\textpm\fi{}00001(\mathrm{stat}{)}_{\ensuremath{-}00095}^{+00081}(\mathrm{expt}\mathrm{syst})$ The associated theoretical uncertainties are mainly due to the choice of renormalization scale $({+6%}{\ensuremath{-}4%})$ and input parton distribution functions $(5%)$
55 citations
TL;DR: In this article, the exclusive gamma signals at the Collider Detector at Fermilab were searched using 87 pb(-1) of data at roots = 1.8 TeV, and 95% C.L.
Abstract: The exclusive gammais not an element of(T) signal has a small standard model cross section and is thus a channel sensitive to new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the Collider Detector at Fermilab, using 87 pb(-1) of data at roots = 1.8 TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale \F\(1/2) in supersymmetric models. For 4, 6, and 8 extra dimensions, model-dependent limits on the fundamental mass scale M-D of 0.55, 0.58, and 0.60 TeV, respectively, are found. We also specify a "pseudo-model-independent" method of comparing the results to theoretical predictions.
40 citations
TL;DR: In this article, a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at roots=630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes was reported.
Abstract: We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at roots=630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800)=0.171+/-.024+/-.012 is in good agreement with next-to-leading order quantum chromodynamics.
23 citations
TL;DR: In this article, the authors report on measurements of the differential cross sections of the meson in the 1S, 2S, and 3S domains, and the measured angular distribution of the muons in the rest frame is consistent with unpolarized meson production.
Abstract: We report on measurements of the $\ensuremath{\Upsilon}(1S)$, $\ensuremath{\Upsilon}(2S)$, and $\ensuremath{\Upsilon}(3S)$ differential cross sections $({d}^{2}\ensuremath{\sigma}{/dp}_{T}\mathrm{dy}{)}_{|y|l0.4}$, as well as on the $\ensuremath{\Upsilon}(1S)$ polarization in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ using a sample of $77\ifmmode\pm\else\textpm\fi{}3{\mathrm{pb}}^{\ensuremath{-}1}$ collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay $\ensuremath{\Upsilon}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. The measured angular distribution of the muons in the $\ensuremath{\Upsilon}(1S)$ rest frame is consistent with unpolarized meson production.
22 citations
TL;DR: In this paper, the diffractive structure function of the antiproton was measured from a study of dijet events produced in association with a leading antroton in (p) over barp collisions at roots = 630 GeV at the Fermilab Tevatron.
Abstract: We report a measurement of the diffractive structure function F-jj(D) of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in (p) over barp collisions at roots = 630 GeV at the Fermilab Tevatron. The ratio of F-jj(D) at roots = 630 GeV to F-jj(D) obtained from a similar measurement at roots = 1800 GeV is compared with expectations from QCD factorization and other theoretical predictions. We also report a measurement of the xi (x-Pomeron) and beta (x of parton in Pomeron) dependence of F-jj(D) at roots = 1800 GeV . In the region 0.035 < ξ < 0.095 , \t\ < 1 GeV2 , and β < 0.5 , F-jj(D)(beta, xi) is found to be of the form beta(-1.0+/-0.1) xi(-0.9+/-0. 1) , which obeys beta-xi factorization.
20 citations
TL;DR: In this paper, the branching ratio of the decays of B+-->chi(c1)(0)(1P)K+ and B++-->J/psiK(+)pi(+)π(+) pi(-) was measured.
Abstract: We report on measurements of the branching ratios of the decays B+-->chi(c1)(0)(1P)K+ and B+-->J/psiK(+)pi(+)pi(-), where chi(c1)(0)(1P)-->J/psigamma and J/psi-->mu(+)mu(-) in p (p) over bar collisions at roots=1.8 TeV. Using a data sample from an integrated luminosity of 110 pb(-1) collected by the Collider Detector at Fermilab we measure the branching ratios to be BR(B+-->chi(c1)(0)(1P)K+)=15.5+/-5.4(stat)+/-1.5(syst)+/-1.3(br)x10(-4) and BR(B+-->J/psiK(+)pi(+)pi(-))=6.9+/-1.8(stat)+/-1.1(syst)+/-0.4(br)x10(-4) where (br) is due to the finite precision on BR(B+-->J/psiK(+)), BR(chi(c1)(0)(1P)-->J/psigamma) is used to normalize the signal yield, and (syst) encompasses all other systematic uncertainties.
20 citations
TL;DR: In this article, 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 Tevatron is presented.
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.
16 citations
TL;DR: In this article, the supersymmetric partner of the top quark (stop) in 107 pb(-1) of p (p) over bar collisions at roots=1.8 TeV collected by the Collider Detector at Fermilab (CDF).
Abstract: We have searched for pair production of the supersymmetric partner of the top quark (stop) in 107 pb(-1) of p (p) over bar collisions at roots=1.8 TeV collected by the Collider Detector at Fermilab (CDF). Each stop is assumed to decay into a lepton, bottom quark, and supersymmetric neutrino. Such a scenario would give rise to events with two leptons, two hadronic jets, and a substantial imbalance of transverse energy. No evidence of such a stop signal has been found. We exclude stop masses in the region (80less than or equal tom((t) over bar)less than or equal to135 GeV/c(2)) in the mass plane of stop versus sneutrino.
TL;DR: In this article, the authors performed a search for radiative b-hadron decays using events produced in p (p) over bar collisions at roots=1.8 TeV and collected by the Collider Detector at Fermilab.
Abstract: We have performed a search for radiative b-hadron decays using events produced in p (p) over bar collisions at roots=1.8 TeV and collected by the Collider Detector at Fermilab. The decays we considered were (B) over bar (0)(d)→(K) over bar*(0)(→K(-)pi(+))gamma, (B) over bar (0)(s)→phi(→K+K-)gamma, Lambda(b)(0)→Lambda(→ppi(-))gamma, and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external photon conversion before the tracking detector volume. By combining the two methods we obtain upper limits on the branching fractions for the (B) over bar (0)(d), (B) over bar (0)(s), and Lambda(b)(0) radiative decays which, at the 95% confidence level, are found to be B((B) over bar (0)(d)→(K) over bar*(0)gamma) lt 1.4x10(-4), B((B) over bar (0)(s)→phigamma) lt 1.6x10(-4), and B(Λ(0)(b)→Lambdagamma) lt 1.9x10(-3).
TL;DR: 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, is reported.
Abstract: We report a study of the decays B-0 --> J/psiK((*)0) pi(+) pi(-), which involve the creation of a u(u) over bar or d(d) over bar quark pair in addition to a (b) over bar --> (c) over bar(c(s) over bar) decay. The data sample consists of 110 pb(-1) of p(p) over bar collisions at roots = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching fractions to be B(B-0 --> J/psiK(*0) pi(+) pi(-)) = (6.6 +/- 1.9 +/- 1.1) X 10(-4) and B(B-0 --> J/psiK(0) pi(+) pi(-)) = (10.3 +/- 3.3 +/- 1.5) X 10(-4). Evidence is seen for contributions from psi(2S)K-(*)0, J/psiK(0) rho(0), J/psiK(*+) pi(-), and J/psiK(1)(1270).
TL;DR: In this paper, the authors performed a search for radiative b-hadron decays using events produced in $p\overline{p}$ collisions at Fermilab.
Abstract: We have performed a search for radiative b-hadron decays using events produced in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{TeV}$ and collected by the Collider Detector at Fermilab. The decays we considered were ${B}_{d}^{0}\ensuremath{\rightarrow}{K}^{*0}(\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})\ensuremath{\gamma},$ ${B}_{s}^{0}\ensuremath{\rightarrow}\ensuremath{\varphi}(\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}})\ensuremath{\gamma},$ ${\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}(\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}})\ensuremath{\gamma},$ and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external photon conversion before the tracking detector volume. By combining the two methods we obtain upper limits on the branching fractions for the ${B}_{d}^{0},$ ${B}_{s}^{0},$ and ${\ensuremath{\Lambda}}_{b}^{0}$ radiative decays which, at the 95% confidence level, are found to be $\mathcal{B}({B}_{d}^{0}\ensuremath{\rightarrow}{K}^{*0}\ensuremath{\gamma})l1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4},$ $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}\ensuremath{\varphi}\ensuremath{\gamma})l1.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4},$ and $\mathcal{B}({\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma})l1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}.$
TL;DR: In this article, the authors search 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 p p collisions at 1.8 TeV at Fermilab.
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 p 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 χ20→γχ10, and a model where the photon is produced in the neutralino decay into the gravitino LSP, χ10→γG. We also present our limits in a model-independent form and test methods of applying model-independent limits.
TL;DR: In this article, the authors present the results of a search for anomalous production of events containing a photon with large transverse energy and a lepton, with the possible exception of photon-lepton events with large T energy.
Abstract: We present the results of a search in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{TeV}$ for anomalous production of events containing a photon with large transverse energy and a lepton $(e$ or $\ensuremath{\mu})$ with large transverse energy, using $86 {\mathrm{pb}}^{\ensuremath{-}1}$ of data collected with the Collider Detector at Fermilab during the 1994--1995 collider run at the Fermilab Tevatron. The presence of large missing transverse energy $({E}_{T}),$ additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large ${E}_{T},$ for which the observed total is 16 events and the expected mean total is $7.6\ifmmode\pm\else\textpm\fi{}0.7$ events.
21 Mar 2002-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a non-parametric method was proposed for the energy reconstruction of the ATLAS barrel prototype combined calorimeter, consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part.
Abstract: This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known e/h ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within ±1% of the true values and the fractional energy resolution is [(58±3)%/ E +(2.5±0.3)%]⊕(1.7±0.2)/E . The value of the e/h ratio obtained for the electromagnetic compartment of the combined calorimeter is 1.74±0.04 and agrees with the prediction that e/h>1.66 for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV .
TL;DR: In this article, the branching ratio B(J/psi→mu(+)mu(-)) has been measured in the forward pseudorapidity region: Bxdsigma[(p) over bar +p→J/PSi(p(T) gt 10 GeV/c,2.1 lt \eta\ lt 2.6)+X]/deta=192+/-9(stat)+/- 29(syst) pb.
Abstract: The inclusive cross section for J/psi production times the branching ratio B(J/psi→mu(+)mu(-)) has been measured in the forward pseudorapidity region: Bxdsigma[(p) over bar +p→J/psi(p(T) gt 10 GeV/c,2.1 lt \eta\ lt 2.6)+X]/deta=192+/-9(stat)+/- 29(syst) pb. The results are based on 74.1+/-5.2 pb(-1) of data collected by the CDF Collaboration at the Fermilab Tevatron Collider. The measurements extend earlier measurements of the D0 Collaboration to higher p(T)(J/psi). In the kinematic range where the experiments partially overlap, these data are in good agreement with previous measurements.
Journal Article•
TL;DR: In this article, the first general search for new heavy particles, X, which decay via X → WZ(0) → enu + jj as a function of M-X and Gamma(X) in p(p) over bar collisions at roots = 1.8 TeV was presented.
Abstract: We present the first general search for new heavy particles, X, which decay via X → WZ(0) → enu + jj as a function of M-X and Gamma(X) in p(p) over bar collisions at roots = 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 lit-nits on the production of new heavy charged vector bosons which decay via W' → WZ(0) 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.