CDF Detector Research Articles

The CDF MiniPlug calorimeters at the Tevatron

Two MiniPlug calorimeters, designed to measure the energy and lateral position of particles in the pseudorapidity region of 3.6<| η|<5.1 of the CDF detector, have been installed as part of the Run II CDF upgrade at the Tevatron collider. Detector performance and first results from p̄p collision data are presented.

Search for new particles or gauge bosons decaying into dileptons/dijets at the tevatron

The existence of new particles decaying in a jet or lepton pair is probed with the Run II data collected by the Tevatron ${\rm{p}}\bar{\rm{p}}$ collider at $\sqrt{s}\!=\!1.96\,{\rm{TeV}}$ . Searches performed on both jet and lepton data collected by the CDF and DO detectors do not show signs of any new resonance within the considered mass range. The sensitivity achieved by these searches leads to 95% C.L. limits on the production cross-section times branching ratio for axigluons, flavour universal colorons, excited quarks, colour octet techni-ρ, E6 diquarks, new gauge bosons and Randall-Sundrum gravitons. Excluded mass regions for these models are also computed. PACS 13.85.Rm Limits – 14.80.-j Other gauge bosons – 14.70.Pw Other particles – 12.60.-i Models

Erratum: Measurement of thett¯production cross section inpp¯collisions ats=1.8TeV[Phys. Rev. D64, 032002 (2001)

We update the measurement of the top production cross section using the CDF detector at the Fermilab Tevatron. This measurement uses $t\bar{t}$ decays to the final states $e+\nu$+jets and $\mu+\nu$+jets. We search for $b$ quarks from $t$ decays via secondary-vertex identification or the identification of semileptonic decays of the $b$ and cascade $c$ quarks. The background to the $t\bar{t}$ production is determined primarily through a Monte Carlo simulation. However, we calibrate the simulation and evaluate its uncertainty using several independent data samples. For a top mass of 175 $GeV/c^2$, we measure $\sigma_{t\bar{t}}=5.1 \pm 1.5$ pb and $\sigma_{t\bar{t}}=9.2 \pm 4.3$ pb using the secondary vertex and the lepton tagging algorithms, respectively. Finally, we combine these results with those from other $t\bar{t}$ decay channels and obtain $\sigma_{t\bar{t}} = 6.5^{+1.7}_{-1.4}$ pb.

The SVX4 integrated circuit

A first prototype of the SVX4 readout IC with enclosed transistor layout for radiation tolerance has been fabricated in a commercial 0.25 μm bulk CMOS process. The SVX4 is intended to instrument the CDF and D0 Run IIB silicon strip detector upgrades at Fermilab. The design and test results are discussed.

Gauge boson production at the tevatron

We present measurements on gauge boson production from data taken during 1994–1996 by the DØ and CDF detectors: the differential production cross section of the W boson as a function of the transverse momentum [1,2], the ratio of W and Z differential cross sections [3,4], direct photon cross-sections at √ s=630 and 1800 GeV [5,6], and studies of Drell-Yan production [7,8]. All measurements are in good agreement with currently available theoretical predictions in most of the measured kinematic range.

CDF — Run II status and prospects

After a five year upgrade period, the CDF detector located at the Fermilab Tevatron Collider is back in operation taking high quality data with all subsystems functional. We report on the status of the CDF experiment in Run II and discuss the start-up of the Tevatron accelerator. First physics results from CDF are presented. We also discuss the prospects for B physics in Run II, in particular the measurements of B s 0 flavour oscillations and CP violation in B decays.

The RASNIK real-time relative alignment monitor for the CDF inner tracking detectors

We describe the design and operation of the RASNIK optical relative alignment system designed for and installed on the CDF inner tracking detectors. The system provides low-cost minute-by-minute alignment monitoring with submicron precision. To reduce ambiguities, we modified the original three-element RASNIK design to a two-element one. Since the RASNIKs are located within 10– 40 cm of the beam line, the systems were built from low-mass and radiation-hard components and are operated in a mode which reduces damage from radiation. We describe the data-acquisition system, which has been running without interruption since before the CDF detector was rolled into its collision hall in March 2001. We evaluate what has been learned about sources of detector motion from almost 2 years of RASNIK data and discuss possible improvements to the system.

First run II results with the CDF detector

We report the first results obtained by the CDF collaboration from the analysis of the Tevatron Run II data collected until June 2002. All components of the CDF detector are operating at or near the design specifications. Typical physics signals are observed and used both to characterize the CDF detector performance, and to make several physics measurements. In spite of the still limited accumulated luminosity some measurements are already competitive with the best currently available.

First run II results with the CDF detector

We report the first results obtained by the CDF collaboration from the analysis of the Tevatron Run II data collected until June 2002. All components of the CDF detector are operating at or near the design specifications. Typical physics signals are observed and used both to characterize the CDF detector performance, and to make several physics measurements. In spite of the still limited accumulated luminosity some measurements are already competitive with the best currently available.

B physics at the Tevatron

A vibrant B physics program is being pursued at the Tevatron for Run II using the upgraded accelerator complex and the upgraded CDF and D0 detectors with the goal of collecting 2fb −1 of integrated luminosity. This will provide measurements of various CP parameters which both complement and extend the programs at the B factories. There are also a variety of spectroscopy measurements currently available only at the Tevatron. The detectors are now largely commissioned and data acquisition is underway.

The CDF silicon detector upgrade and performance

Abstract The CDF silicon tracking and vertexing system for Run2a of the Tevatron consists of eight layers, arranged in cylinders, spanning radii from 1.35 to 28 cm , and lengths from 90 cm to nearly 2 m for a total of 6 m 2 of silicon and 722,000 readout channels. This article will cover the last phase of detector assembly as well as the internal alignment of the subdetectors. The installation of the silicon into the main CDF detector, its commissioning and data taking will be discussed. First results will show signal to noise and charge collection of the ladders as well as the global alignment of the CDF drift chamber and the silicon detector with respect to each other and to the beam.

Tevatron B-physics: recent results and prospects

Between 1992 and 1996, the CDF and D0 experiments have collected data samples of 110 pb −1 each of p p collisions at √ s = 1.8 TeV at the Fermilab Tevatron. In the year 2001 the Tevatron commenced p p collisions again at √ s = 1.96 TeV with the goal of delivering an integrated luminosity of 1 fb −1 per year. In the mean time the CDF and D0 detectors have undergone substantial upgrades which allow for a rich B physics program with unique capabilities. In this paper we discuss recent results and the B Physics prospects at the Tevatron with 2 fb −1 of data (Run IIa) or 15 fb −1 of data (Run IIa+Run IIb).

Status report of the intermediate silicon layers detector at CDFII

The Intermediate Silicon Layers detector (ISL) is a large radius silicon tracker, installed in the CDF detector for the RUN II of the Tevatron Collider. With almost 4 m 2 of double-sided silicon sensors and 300,000 electronic channels it represents the biggest system of this kind ever built. The construction and installation phases, the performed quality assurance tests as well as the problems encountered are reviewed. RUN II of the Tevatron officially started on March 1st, 2001. Although the CDF silicon system is still being commissioned, results on the performance of the ISL detector obtained using the first data are presented.

THEORETICAL AND EXPERIMENTAL STATUS OF MAGNETIC MONOPOLES

The Tevatron has inspired new interest in the subject of magnetic monopoles. First there was the 1998 D0 limit on the virtual production of monopoles, based on the theory of Ginzburg and collaborators. In 2000 the first results from an experiment (Fermilab E882) searching for real magnetically charged particles bound to elements from the CDF and D0 detectors were reported. This also required new developments in theory. The status of the experimental limits on monopole masses will be discussed, as well as the limitation of the theory of magnetic charge at present.

Study of the heavy flavor content of jets produced in association withWbosons inpp¯collisions ats=1.8TeV

We present a detailed examination of the heavy flavor content of the $W $ + jet data sample collected with the CDF detector 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 $\pm$ 0.6 events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.

Measurement of theB+total cross section andB+differential cross sectiondσ/dpTinpp¯collisions ats=1.8 TeV

We present measurements of the B+ meson total cross section and differential cross section $d\sigma/ dp_T$. The measurements use a $98\pm 4$ pb^{-1} sample of $p \bar p$ collisions at $\sqrt{s}=1.8$ TeV collected by the CDF detector. Charged $B$ meson candidates are reconstructed through the decay $B^{\pm} \to J/\psi K^{\pm}$ with $J/\psi\to \mu^+ \mu^-$. The total cross section, measured in the central rapidity region $|y|<1.0$ for $p_T(B)>6.0$ GeV/$c$, is $3.6 \pm 0.6 ({\rm stat} \oplus {\rm syst)} \mu$b. The measured differential cross section is substantially larger than typical QCD predictions calculated to next-to-leading order.

Study of B0 --> J/psiK(*)0pi(+)pi(-) decays with the collider detector at Fermilab.

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).

Search for narrow diphoton resonances and forγγ+W/Zsignatures inpp¯collisions ats=1.8 TeV

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 p\bar p collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both p\bar p\to\gamma\gamma + X and p\bar p\to\gamma\gamma + W/Z. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale sqrt{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 H\to\gamma\gamma. Finally, we set a lower limit on the mass of a `bosophilic' Higgs boson (e.g. one which couples only to \gamma, W, and Z$ bosons with standard model couplings) of 82 GeV/c^2 at 95% confidence level.

QUARKONIA PRODUCTION AND POLARIZATION STUDIES WITH CDF

In this paper we present results on production and polarization of the J/ψ, ψ(2S), χc, ϒ and χb states at [Formula: see text]. These results were obtained from data taken with the CDF detector at Fermilab. We cover recently completed analyses of the 1992-96 collider run.

STUDY OF JET ENERGY RESOLUTION AT CDF

The jet energy resolution comes from many sources, which can be grouped into two categories: (1) detector effects such as calorimeter resolution, and (2) physics effects such as fluctuations in the energy outside a clustering cone. For the detector resolution we used both CDF detector simulation and data. For the first time the full granularity of the CDF detector is used to perform corrections at "tower level" rather than at "jet level". The track momenta measured by the Central Tracking Chamber and the neutral cluster energies measured by the Central Shower Max are used to correct the calorimeter tower energies. When tested on γ + jet data, our new algorithm has shown an improvement on the jet energy resolution better than 20% compared to the standard CDF jet corrections.