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Studies of the top quark at the Tevatron

Description: We report on studies of the top quark, beyond the measurements of its mass and produciton cross section, which have been carried out recently by the CDF and D0 collaborations, based on {approximately}110{+-}6 pb{sup -1} of proton-antiproton collisions at a center-of-mass energy of 1.8 TeV. Each experiment has searched for t{yields}H{sup +}b decays and, from the lack of observable signal, excluded previously unexplored regions of the [M{sub H+},tan{beta}] parameter space. D0 has studied the correlation between the spin states of pair-produced top quarks, and CDF has studied the helicity of the W bosons produced in the decay of top quarks. Within large statistical uncertainties, both measurements agree with predictions of the standard model.
Date: May 28, 1999
Creator: Chakraborty, Dhiman
Partner: UNT Libraries Government Documents Department

Charmed meson and onium production at the Tevatron

Description: The authors report recent results of D*{sup {+-}} meson, J/{psi} and {Upsilon} production at the Fermilab Tevatron. They observe about 8,000 D*{sup {+-}} mesons reconstructed in the decay chain of D* {r_arrow} D{sub {pi}}{sup 0}, D{sup 0} {r_arrow} K{mu}+X. They measure the integrated D*{sup +} production cross section to be 347 {+-} 65(stat.) {+-} 58(sys.) nb for the rapidity range {vert_bar}{eta}(D*{sup +}){vert_bar} < 1.0 and the transverse momentum range p{sub T} (D*{sup +}) > 10 GeV/c. The measurement is slightly higher than the theoretical prediction, especially at lower pT range. We also measure the polarization of J/{psi} at production and find that the measured transverse polarization is not well explained by the color-octet model proposed to explain the anomalously high J/{psi} production cross section. We also present a new result on {Upsilon} production and polarization. Production of the {Upsilon} is consistent with being unpolarized.
Date: December 20, 2000
Creator: Nakaya, T.
Partner: UNT Libraries Government Documents Department

Electroweak and B physics results from the Fermilab Tevatron Collider

Description: This writeup is an introduction to some of the experimental issues involved in performing electroweak and b physics measurements at the Fermilab Tevatron. In the electroweak sector, we discuss W and Z boson cross section measurements as well as the measurement of the mass of the W boson. For b physics, we discuss measurements of B{sup 0}/{bar B}{sup 0} mixing and CP violation. This paper is geared towards nonexperts who are interested in understanding some of the issues and motivations for these measurements and how the measurements are carried out.
Date: January 30, 2001
Creator: Pitts, K.T.
Partner: UNT Libraries Government Documents Department

Dijet production by double pomeron exchange at the Tevatron

Description: The authors report the observation of dijet events with a Double Pomeron Exchange topology produced in {bar p}p collisions at {radical}s = 1,800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a rapidity gap on the outgoing proton side. Results on kinematics, production rates, and comparisons with corresponding results from single diffractive and inclusive dijet production are presented.
Date: December 21, 2000
Creator: Terashi, Koji
Partner: UNT Libraries Government Documents Department

C0 low-{beta} optics

Description: A low-{beta} insertion has been designed for the BTeV experiment at C0. With {+-} 12 m for detector space, a {beta}* of 0.5 m can be achieved using 170 T/m magnets in the final focus triplets. A total half-crossing angle of 240 {micro}r is necessary to keep the beams separated by 5{sigma} at the 2nd parasitic crossing. There are 2 possible Tevatron collision scenarios: B0 and D0, but not C0, and; C0, but not B0 or D0.
Date: February 2, 2001
Creator: Johnstone, J.A.
Partner: UNT Libraries Government Documents Department

W, Z + jets at Tevatron

Description: We report the production jet cross-sections and properties in W and Z events using data from collisions with {radical}s = 1800 GeV at Fermilab Tevatron. Observed distributions in general agree with predictions of leading order QCD matrix element calculations with added gluon radiations and simulated parton fragmentations; however, some limitations of LO QCD predictions are also observed. The cross-section ratio of W + {>=} 1 jet events to inclusive W events is reported and compared with next-to-the-leading order QCD expectations. Good agreement between data and theory is seen. The color coherence effects are also observed in W+ jets events.
Date: May 3, 1999
Creator: Chang, Paoti
Partner: UNT Libraries Government Documents Department

Prospects for higgs at the Tevatron

Description: The current status of simulation studies for the observation of a standard-model or lightest supersymmetric Higgs boson at TeV33 are reviewed. Latest studies indicate that the mass range 60 < m{sub H} {approx_lt} 130 GeV can be covered at the 5-standard-deviation level with 30 fb{sup -1}, using the WH and ZH channels. This is the full allowed mass range for the lightest Higgs h of minimal supersymmetry.
Date: February 1, 1998
Creator: Womersley, J.
Partner: UNT Libraries Government Documents Department

Present searches for Higgs signatures at the Tevatron

Description: We present results for various searches for signatures of standard and non-standard model Higgs boson decays conducted at the collider detectors CDF and D0 using {approx}100 pb{sup -1} of integrated luminosity each from the Tevatron collider Run 1 (1992-96) at {radical}s=1.8 TeV. No evidence for a Higgs boson decay is found and various limits are set.
Date: August 1, 1997
Creator: Groer, L.
Partner: UNT Libraries Government Documents Department

Top quark physics: Overview

Description: In this presentation I will primarily focus on top quark physics but I will include a discussion of the W-boson mass and the possibility of discovering a light Higgs boson via associated production at the Tevatron.
Date: January 1, 1998
Creator: Parke, S.
Partner: UNT Libraries Government Documents Department

Search for new particles in multijet final states at the Tevatron

Description: We present the latest results of the searches for new particles in hadronic final states performed in p{anti p} collisions at {radical}s=1.8 TeV. The large data samples collected with the CDF and D0 detectors at the Tevatron collider between 1992 and 1995 allow searches for low cross section phenomena in dijet and multijet events, despite the hindrance of the high background from normal QCD processes. However no signal for new physics is found, and the data show good agreement with QCD. Limits on the mass and on the cross section of the searched states can thus be set.
Date: August 1, 1997
Creator: Dorigo, T.
Partner: UNT Libraries Government Documents Department

Switchyard in the Main Injector era conceptual design report

Description: This report presents elements of a design of the Switchyard and of the present fixed target beamlines in the era of the Main Injector (MI). It presumes that 800 GeV Tevatron beam will be transported to this area in the MI era, and permits it to share cycles with 120 GeV Main Injector beam if this option is desired. Geographically, the region discussed extends from the vicinity of AO to downstream points beyond which beam properties will be determined by the requirements of specific experiments. New neutrino lines not utilizing the present Switchyard (NuMI, BooNE) are not addressed. Similarly Main Injector beams upstream of AO are described fully in MI documentation and are unaffected by what is presented here. The timing both of the preparation of this report and of its recommendations for proceeding with construction relate to a desire to do required work in Transfer Hall and Enclosure B during the Main Injector construction shutdown (September 1997 - September 1998). As these areas are off-limits during any Tevatron operation, it is necessary for the fixed target program that work be completed here during this extended down period. The design presented here enables the operation of all beamlines in the manner specified in the current Laboratory plans for future fixed- target physics.
Date: August 1, 1997
Creator: Brown, C.; Kobilarcik, T.; Lucas, P.; Malensek, A.; Murphy, C.T. & Yang, M.-J.
Partner: UNT Libraries Government Documents Department

Recent Tevatron results on b quark production

Description: A number of recent B physics results from the CDF and D0 experiments at the Fermilab Tevatron Collider is reported. Measurements of open b quark production cross section in the central and forward rapidity regions in p{anti p} interactions at {radical}s = 1800 GeV are presented. The measurements are used to evaluate the rapidity dependence of b quark production. We also report recent results on correlated b {anti b} production: a measurement of b {anti b} angular correlations using dimuon triggers (D0) and the first direct measurement of b {anti b} rapidity correlations (CDF). The results from the various measurements are compared with the next-to-leading order QCD predictions. Finally, a measurement by CDF of the polarization of {psi}(2S) mesons is compared with the predictions of the Color Octet Model.
Date: June 1, 1999
Creator: Baarmand, Marc M.
Partner: UNT Libraries Government Documents Department

Online calculation of the Tevatron collider luminosity using accelerator instrumentation

Description: The luminosity of a collision region may be calculated if one understands the lattice parameters and measures the beam intensities, the transverse and longitudinal emittances, and the individual proton and antiproton beam trajectories (space and time) through the collision region. This paper explores an attempt to make this calculation using beam instrumentation during Run 1b of the Tevatron. The instrumentation used is briefly described. The calculations and their uncertainties are compared to luminosities calculated independently by the Collider Experiments (CDF and D0).
Date: July 1, 1997
Creator: Hahn, A.A.
Partner: UNT Libraries Government Documents Department

Tevatron performance goals for the coming decade

Description: Fermilab is in the midst of a program to raise the luminosity in the Tevatron proton-antiproton collider by at least a factor of five above the currently achieved level of 1 .6x10{sup 31} cm{sup -2}sec{sup -l} Components of this program include the construction of a new synchrotron, the Main Injector, a new antiproton storage ring, the Recycler, and a variety of improvements to the existing Antiproton Source and Tevatron. Commissioning of these components will be underway in early 1999 with the next Tevatron collider run scheduled to start in April 2000. Initial commissioning experience with these systems will be described, along with developments underway to support further Tevatron luminosity enhancements over the coming decade.
Date: June 3, 1999
Creator: Holmes, Stephen D.
Partner: UNT Libraries Government Documents Department

Properties of b-quark production at the Tevatron

Description: We report on results obtained by the D0 and CDF collaborations on the properties of b-quark production in p{anti p} collisions at ps = 1:8 TeV. The D0 experiment has measured the inclusive production cross section for muons originating from b-quark decays in the forward region, corresponding to the rapidity range 2:4 < j y {sup {mu}} j < 3:2. Combined with previous measurements in the central region, these results permit a comparison of the rapidity dependence of the b-quark production cross section with the predictions of next-to-leading order QCD. The CDF experiment has achieved the #12;rst direct measurement of b {anti b} rapidity correlations at a hadron collider, with the ratio of the cross sections obtained in two rapidity bins. This measurement is a direct probe of the high-x gluon content of the proton.
Date: October 1, 1998
Creator: Stichelbaut, Frederic
Partner: UNT Libraries Government Documents Department

Vector boson pair production and trilinear gauge boson couplings - Results from the Tevatron

Description: Direct measurements of vector boson pair production processes and trilinear gauge boson couplings have been conducted by the CDF and D0 Collaborations. Preliminary results from searches for anomalous WW/WZ {yields} {mu}{nu} jet jet and WZ {yields} eee{nu} production are presented. 95% CL anomalous coupling limits from previously published D0 results are -0.20< {lambda} < 0.20 ({Delta}{kappa} = 0) and -3.0<{Delta}{kappa} < 0:43 ({lambda} = 0) for {Lambda} = 2000 GeV where the WW{gamma} couplings are assumed to equal the WWZ couplings. Combined D0 + LEP experiment anomalous coupling limits are presented for the #12;rst time. 95% CL limits are -0.16 < {lambda}{sub {gamma}} < 0:10 ({Delta}{kappa} = 0) and -0.15< {Delta}{kappa}{sub {gamma}}#20; < 0:41 ({lambda} = 0) under the assumption that the couplings are related by the \HISZ" constraints. 95% CL anomalous ZZ{gamma} and Z{gamma}{gamma} coupling limits from D0 are jh{sup Z}{sub 30} j < 0:36 (h{sup Z}{sub 40 = 0) and jh{sup Z}{sub 40} j < 0:05 (h{sup Z}{sub 30} = 0) for {Lambda} = 750 GeV. CDF reports the first observation of a ZZ event. Prospects for Run II are discussed.
Date: October 1, 1998
Creator: Diehl, H. T.
Partner: UNT Libraries Government Documents Department

Searches for exotic particles at the Tevatron

Description: This paper reports on recent searches for exotic particles by the CDF and D#31; Collaborations. The results are derived from the data collected during the 1992-95 Run I at the Fermilab Tevatron. Limits are presented on new heavy gauge bosons, leptoquarks, monopoles and technicolor particles.
Date: October 1, 1998
Creator: Grosso-Pilcher, C.
Partner: UNT Libraries Government Documents Department

Report of the Tevatron Higgs working group.

Description: Despite the success of the Standard Model (SM), which provides a superb description of a wide range of experimental particle physics data, the dynamics responsible for electroweak symmetry breaking is still unknown. Its elucidation remains one of the primary goals of future high energy physics experimentation. Present day global fits to precision electroweak data based on the Standard Model favor the existence of a weakly-interacting scalar Higgs boson, which is a remnant of elementary scalar dynamics that drives electroweak symmetry breaking. The only known viable theoretical framework incorporating light elementary scalar fields employs low-energy supersymmetry, where the scale of supersymmetry breaking is {Omicron} (1 TeV). The Higgs sector of the Minimal Supersymmetric extension of the Standard Model (MSSM) is of particular interest because it predicts the existence of a light CP-even neutral Higgs boson with a mass below about 130 GeV. Moreover, over a significant portion of the MSSM parameter space, the properties of this scalar are indistinguishable from those of the SM Higgs boson.
Date: November 14, 2000
Creator: Carena, M.; Conway, J. S.; Haber, H. E.; Hobbs, J. D.; Harris, B. W.; Kuhlmann, S. et al.
Partner: UNT Libraries Government Documents Department

The BTeV pixel detector and trigger system

Description: BTeV is an approved forward collider experiment at the Fermilab Tevatron dedicated to the precision studies of CP violation, mixing, and rare decays of beauty and charm hadrons. The BTeV detector has been designed to achieve these goals. One of the unique features of BTeV is a state-of-the-art pixel detector system, designed to provide accurate measurements of the decay vertices of heavy flavor hadrons that can be used in the first trigger level. The pixel vertex detector and the trigger design are described. Recent results on some of the achievements in the R and D effort are presented.
Date: December 3, 2002
Creator: Kwan, Simon
Partner: UNT Libraries Government Documents Department