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Pion-nucleon scattering in P{sub 11} channel and the Roper resonance

Description: The {pi}N scattering in P{sub 11} channel is investigated within the two-channel model of Pearce and Afnan. The model consists of: (1) vertex interactions b {yields} {pi}N, {pi}{nabla} with b denoting either a bare nucleon or a bare Roper state, (2) a background potential {upsilon}{sub {pi}B,{pi}B} with B = N,{nabla}. Assuming that {upsilon}{sub {pi}B,{pi}B} can be phenomenologically parameterized as a separable form and the {pi}N inelasticity can be accounted for by dressing the {nabla} in the {pi}{nabla} channel by a {nabla} {leftrightarrow} {pi}N vertex, it is found that the fit to the P{sub 11} phase shifts up to 1 GeV favors a large mass of the bare Roper state. Our results are consistent with the findings of Pearce and Afnan that if the mass of the bare Roper state is restricted to be {le}1600 MeV, then a physical Roper will have a width which is too narrow causing a rapid variation of the phase shifts at energies near the resonance energy.
Date: March 1996
Creator: Bugaev, K. A.; Yang, Shin Nan & Lee, T. S. H.
Partner: UNT Libraries Government Documents Department

J/{psi} and {psi}{prime} production at CDF

Description: This paper presents measurements of the J/{psi} and {psi}{prime} production cross sections in p{ovr p} collisions at {radical}s = 1.8 TeV. The cross sections are measured in the kinematic region P{sub T} {gt} 5 GeV/c, {vert_bar}{eta}{vert_bar} {lt} 0.6 using the dimuon decay channel. The fraction of events from B decays is measured and used to calculate the J/{psi} and {psi}{prime} cross sections from B decay. The fraction of J/{psi} events from {chi}{sub c} decays is also measured and used to calculate the J/{psi} cross section from direct production. 11 refs., 5 figs., 1 tab.
Date: July 1, 1996
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Highlights of B physics at CDF

Description: The CDF experiment at the Fermilab Tevatron collider has produced many B physics results. Recent measurements on B meson masses, B lifetimes, B branching ratios, limits on rare B decays, and B flavour tagging studies are reviewed.
Date: August 1, 1995
Creator: Paulini, M.
Partner: UNT Libraries Government Documents Department

Observation of {pi} - B meson charge-flavor correlations and measurement of time dependent B{sup 0} Bbar{sup 0} mixing in p{bar p} collisions

Description: We present evidence for charge correlations of {ital B} mesons with charged particles produced in {ital p{anti p}} Collisions at 1.8 TeV. Such correlations are expected to arise from pious produced in the fragmentation chain and from {ital B}{sup **} decays. We measure the efficiency and purity of this flavor tagging method for both charged and neutral {ital B} mesons. We apply these correlations to {ital B} mesons reconstructed in 110 pb{sup -1} of data collected with the CDF detector at the Fermilab Tevatron Collider. {ital B} mesons are either partially reconstructed, using the semileptonic decays {ital B}{sup 0} {yields} {ital l}{sup +}{ital D}{sup (*)-}{ital X} and {ital B}{sup +} {yields} {ital l}{sup +}{ital {anti D}X}, or fully reconstructed, using the decay modes {ital B}{sup 0} {yields} {ital J/{Psi}K{sup *0}} and {ital B}{sup +} {yields} {ital J/{Psi}K{sup +}}. Application of this new flavor tagging method to neutral {ital B} mesons yields a measurement of the frequency of the oscillation {ital B}{sup 0} {yields} {ital {anti B}}{sup 0}. We obtain {Delta}{ital m{sub d}} = 0.446 {+-} 0.057{sup +0.034}{sub -0.031}.
Date: September 1, 1996
Creator: CDF Collaboration
Partner: UNT Libraries Government Documents Department

Search for new exotic particles at CDF

Description: We present recent results of searches for new particles beyond the Standard Model at the Collider Detector at Fermilab (CDF). These include searches for heavy gauge bosons (Z{prime}, W{prime}), leptoquarks and stable massive charged particles. For most of these particles we set the currently most stringent limits. 15 refs., 7 figs.
Date: July 1, 1996
Creator: Wensel, H.
Partner: UNT Libraries Government Documents Department

Charged Higgs and SUSY searches at CDF

Description: We present recent results of supersymmetric (SUSY) particle searches at the Collider Detector at Fermilab. These include searches for squarks, gluinos, charginos, and neutralinos using the {ital E}{sub T}-multijet, like-sign dilepton, and trilepton SUSY signatures. Results from a charged Higgs search using the hadronic decays of the tau lepton are also presented.
Date: July 1996
Creator: Loomis, C.
Partner: UNT Libraries Government Documents Department

Search for charged Higgs bosons in CDF

Description: We present results of a direct search for charged Higgs production from {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV at Fermilab`s Tevatron collider using the CDF detector. An expanded Higgs sector containing charged Higgs bosons is a persistent feature of candidate theories to replace the Standard Model. The minimal supersymmetric extension of the Standard Model, for example predicts that the dominant decay mode of the top quark is {ital t} {r_arrow} H{sup +}{ital b} {r_arrow} {tau}{sup +} {ital vb} for large values of tan {Beta}. We use the hadronic decays of the tau lepton in this channel to exclude charged Higgs bosons with M{sub H{sup {+-}}} {lt} 140 GeV/c{sup 2} for large tan{Beta}.
Date: August 1, 1996
Creator: Loomis, C.
Partner: UNT Libraries Government Documents Department

Production and decays of top quark pairs in the single lepton and dilepton channels at CDF

Description: We present the results from {ital t}{ital {anti t}} production in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV, with decays into one or two leptons plus multiple jets. The full data set accumulated by the CDF collaboration at the Fermilab Tevatron from 1992 through 1995, corresponding to a total integrated luminosity of 109.4 {+-} 7.2 pb{sup -1}, is used.
Date: August 1, 1996
Creator: Kruse, M. C.
Partner: UNT Libraries Government Documents Department

Search for squarks and gluinos using dileptons

Description: Gluinos and squarks can be produced in {ital p{anti p}} collisions at {radical}s = 1.8 TeV and decay via charginos and neutralinos to final states containing two (or more) leptons. There is no charge correlation between the leptons of charginos from gluino decays as gluinos are Majorana particles. The strategy of this analysis is to search for an excess of events containing two like-sign isolated leptons, missing energy, and jets. The analysis is based on 81 pb{sup -1} of 1994-5 data recorded at CDF.
Date: October 1, 1996
Creator: Done, J. P.
Partner: UNT Libraries Government Documents Department

New particle searches at CDF

Description: We present recent results of searches for new particles beyond the Standard Model at the Collider Detector at Fermilab (CDF). These include searches for supersymmetric (SUSY) particles, charged Higgs, heavy gauge bosons (Z{prime} and W{prime}), and stable massive charged particles. 19 refs., 12 figs.
Date: November 1, 1996
Creator: Maeshima, Kaori
Partner: UNT Libraries Government Documents Department

Top physics prospects in Run II and TeV33

Description: The top production rate in the future Tevatron run at {radical}s = 2 TeV with the increased luminosity is summarized. The expected yield seen by the upgraded detectors which have larger acceptance and better efficiency will give statistical and systematic improvements for various top decay properties and standard model values.
Date: July 1, 1996
Creator: Byon-Wagner, A.
Partner: UNT Libraries Government Documents Department

Hard Diffraction at CDF

Description: We present new evidence for events with a rapidity gap between jets in {bar p}-p collisions at {radical}s = 1.8 TeV based on data collected by triggering the Collider Detector at Fermilab on two high transverse momentum forward jets and results of a search for diffractive W{+-} and dijet production where diffraction is tagged by the rapidity gap technique. We also present the results of a search for diffractive dijets using data collected by triggering on a very forward particle in the recently installed roman-pot detectors. The dijet events exhibit additional diffractive characteristics such as rapidity gaps and boosted center of mass system, however the recoil antiproton measured in the roman-pots is in a regime in which the non- pomeron contribution is significant.
Date: July 1996
Creator: Melese, P. L.
Partner: UNT Libraries Government Documents Department

Measurement of the lifetime of the B{sup o}{sub s} meson from D{sup minus}{sub s}{ell}{sup plus} correlations

Description: The lifetime of the B{sub s}{sup 0} meson is measured using the semileptonic decay B{sub s}{sup 0} {r_arrow} D{sub s}{sup {minus}}l{sup {plus}}{nu}X. The data sample consists of approximately 110 pb{sup {minus}1} of p{ovr p} collisions at {radical}s = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider. There are 254{plus_minus}21 D{sub s}{sup {minus}}l{sup {plus}} signal events where the D{sub s}{sup {plus}} is reconstructed through its decay mode D{sub s}{sup {minus}} {r_arrow} {phi}{pi}{sup {minus}}, {phi} {r_arrow} K{sup {plus}}K{sup {minus}}. Using these events, the B{sub s}{sup 0} meson lifetime is determined to be {tau}(B{sub s}{sup 0}) {equals} 1.37{sup {plus}0.14}{sub {minus}0.12}(stat.){plus_minus}0.04(syst.) ps. The B{sub s}{sup 0} meson proper decay length distribution has been examined for a lifetime difference between the two CP eigenstates of the B{sub s}{sup 0} meson, B{sub s}{sup H} and B{sub s}{sup L}. 12 refs., 3 figs., 1 tab.
Date: July 1996
Creator: Burkett, K. & Paulini, M.
Partner: UNT Libraries Government Documents Department

Branching fractions of B{sup plus} {r_arrow} {Psi}(2S)K{sup plus} and B{sup O} {r_arrow} {Psi}(2S)K{sup {asterisk}0} decays at CDF

Description: This paper describes the observation of the decays B{sup {plus}} {r_arrow} {psi}(2S)K{sup {plus}} and B{sup 0} {r_arrow} {psi}(2S)K{sup {asterisk}}(892){sup 0} in 1.8 TeV p{ovr p} collisions and presents measurements of the branching fractions Br(B{sup {plus}} {r_arrow} {psi}(2S)K{sup {plus}}) and Br(B{sup 0} {r_arrow} {psi}(2S)K{sup {asterisk}}(892){sup 0}) relative to Br(B{sup {plus}} {r_arrow} J/{psi}K{sup {plus}}) and Br(B{sup 0} {r_arrow} J/{psi}K{sup {asterisk}}(892){sup 0}), respectively. The {psi}(2S) mesons are reconstructed in both the {psi}(2S) {r_arrow} {mu}{sup {plus}}{mu}{sup {minus}} and {psi}(2S) {r_arrow} J/{psi}{pi}{sup {plus}}{pi}{sup {minus}} channels. The world average branching fractions for the J/{psi} channels are used to extract the absolute branching fractions Br(B{sup {plus}} {r_arrow} {psi}(2S)K{sup {plus}}) = (6.8{plus_minus}1.0(stat.){plus_minus}1.4(syst.)){times}10{sup {minus}4} and Br(B{sup 0} {r_arrow} {psi}(2S)K{sup {asterisk}}(892){sup 0}) = (9.0{plus_minus}2.1(stat.){plus_minus}2. 0(syst.)){times}10{sup {minus}4}. 9 refs., 13 figs., 8 tabs.
Date: July 1, 1996
Creator: Warburton, A.
Partner: UNT Libraries Government Documents Department

Search for charginos and neutralinos using trileptons

Description: We search for supersymmetry (SUSY) using trilepton events in {ital p{anti p}} collisions at {radical}s = 1.8 TeV. In the Minimal Supersymmetric Standard Model (MSSM), trilepton events are expected from chargino-neutralino ({anti {chi}}{sub 1}{sup {+-}}{anti {chi}}{sub 2}{sup 0}) pair production, with subsequent decay into leptons. In all possible combinations of electron and muon channels in 100 pb{sup -1} of data, we observe no events which pass our trilepton selection criteria. Assuming the GUT hypothesis within the framework of the MSSM, our preliminary analysis excludes M({anti {chi}}{sub 1}{sup {+-}}) < 68 GeV/c{sup 2}.
Date: October 1, 1996
Creator: Done, J. P.
Partner: UNT Libraries Government Documents Department

W/Z at CDF

Description: Results are presented based on 19 {ital pb}{sup -1} of data collected by the CDF detector during the 1992-1993 collider run at the Fermilab Tevatron. These results include measurements of the {ital W} mass and {sigma}{center_dot}{ital B} for {ital W} and {ital Z decays} using both the electron and muon channels. In addition to extracting the total width of the {ital W} width using the electron decay channel is also presented.
Date: August 1, 1996
Creator: Thurman-Keupp, R. M.
Partner: UNT Libraries Government Documents Department

Implementation of the shower max electron trigger at CDF

Description: The authors have built and installed new electronics which brings the central shower max detector into the CDF Level-2 trigger. By matching a stiff track from the central fast track processor to an associated shower max cluster, this trigger improvement reduces the electron Level-2 cross section by approximately 50% while retaining greater than 85% of real electrons and allows the authors to lower their electron trigger threshold.
Date: June 1, 1994
Creator: Byrum, K.; Dawson, J.; Nodulman, L.; Wicklund, A.B.; Amidei, D.; Burkett, K. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the B meson differential cross-section in p{bar p} collisions at {radical}s = 1.8 TeV

Description: This paper presents a direct measurement of the differential {ital B}{sup +} and {ital B}{sup 0} cross sections, {ital d{sigma}/dp{sub T}} in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV using a sample of 74 {ital pb}{sup -1} accumulated by the Collider Detector at Fermilab (CDF). The cross sections are measured in the central pseudorapidity region {vert_bar}{eta}{vert_bar} {lt} 1 for {ital p{sub T}}({ital B}) {gt} 6.0 GeV/c by fully reconstructing the {ital B} meson decays {ital B}{sup +} {r_arrow} {ital J/{psi}K{sup +}} and {ital B}{sup 0} {r_arrow} {ital J/{psi}K{sup *0}}(892), where {ital J/{psi}} {r_arrow} {mu}{sup +}{mu}{sup -} and {ital K}{sup *0} {r_arrow} {ital K}{sup +}{pi}{sup -}. The prediction of next-to- leading order QCD is consistent with the shape of the differential cross section but is low by a factor of 2.1{+-}0.2{+-}0.3. The integrated {ital B} meson cross section for {ital p{sub T}}({ital B}) {gt} 6.0 GeV/c is determined to be {sigma}({ital B}{sup -} = 3. 54{+-}0.22{+-}0.53 {mu}{ital b}.
Date: July 1996
Creator: Laasanen, A.
Partner: UNT Libraries Government Documents Department

Quarkonia production at CDF

Description: In this paper we present results on {ital J}/{Psi}, {Psi}(2{ital S}), {chi}{sub {ital c}} and {Gamma} production at {radical}{ital s} = 1.8 TeV. These results were obtained from data taken with the CDF detector at Fermilab. We cover recently completed analyses of the 1992-1995 collider run. We find an excess of {ital J}/{Psi}, {Psi}(2{ital S}) and {Gamma} production compared with the predictions from the Color Singlet Model. Prospects for the near future are also discussed.
Date: November 1, 1996
Creator: Papadimitriou, V.
Partner: UNT Libraries Government Documents Department

A search for neutral heavy vector gauge bosons in {anti p}p collisions at {radical}s = 1.8 TeV

Description: A search for a neutral heavy vector gauge boson, {ital Z}`, was conducted in {ital p{anti p}} collisions using 110 pb{sup -1} of data obtained at the Collider Detector at Fermilab. We present preliminary 95% CL limits on the production of {ital Z}` in different models using its {ital e}{sup +}{ital e}{sup -} and {mu}{sup +}{mu}{sup -} decay modes.
Date: September 1, 1996
Creator: CDF Collaboration
Partner: UNT Libraries Government Documents Department

Measurement of the mass of the B{sub s}{sup 0} meson in {bar p}p collisions at {radical}s = 1.8 TeV

Description: We measure the mass of the B{sub s}{sup 0} meson by fully reconstructing the decay B{sub s}{sup 0} {yields} J/{psi} {phi} with the subsequent decays J/{psi} {yields} {mu}{sup +} {mu}{sup {minus}} and {phi} {yields} K{sup +} K{sup {minus}}. The data was obtained from 19.3 pb{sup {minus}1} of integrated luminosity of {bar p}p collisions at {radical}s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A sample of 80,000 inclusive J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}} events is used to study systematic biases in track reconstruction and is used to calibrate the momentum scale. We reconstruct the kinematically similar decays B{sup {minus}} {yields} J/{psi} K{sup {minus}} and B{sup 0} {yields} J/{psi} K* to study the mass measurement technique used for the B{sup 0} meson. Based on the observation of 32 {plus_minus} 6 candidates, the mass of the B{sub s}{sup 0} meson is measured to be 5369.9 {plus_minus} 2.3 {plus_minus} 1.3 MeV/c{sup 2}.
Date: July 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Remote data monitoring for CDF

Description: Remote data monitoring from the physicists` home institutions has become an important issue in large international experiments to ensure high performance of the detectors and high quality of data and scientific results. The CDF experiment is a collaboration of 450 physicists from 36 institutions in the U.S., Japan, Canada, Italy and Taiwan. Future experiments at Fermilab, CERN and elsewhere will be even larger, and will be performed over a period of order 10 years. The ability of collaborators at remote sites to monitor the increasingly complex detectors and feed the results back into the data acquisition process will be of great importance We report on the status and performance of remote monitoring from Japan of the CDF experiment in Batavia Illinois. We also discuss feasibilities for modest Remote Control Rooms.
Date: November 1, 1995
Creator: Kippenhan, H. A., Jr.; Lidinsky, W. & Roediger, G.
Partner: UNT Libraries Government Documents Department