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The D0 Upgrade (open access)

The D0 Upgrade

In this paper we describe the approved DO Upgrade detector, and its physics capabilities. The DO Upgrade is under construction and will run during the next Fermilab collider running period in early 1999 (Run II). The upgrade is designed to work at the higher luminosities and shorter bunch spacings expected during this run. The major elements of t he upgrade are: a new tracking system with a silicon tracker, scintillating fiber tracker, a 2T solenoid, and a central preshower detector; new calorimeter electronics; new muon trigger and tracking detectors with new muon system electronics; a forward preshower detector; new trigger electronics and DAQ improvements to handle the higher rates.
Date: July 1995
Creator: Abachi, S.
System: The UNT Digital Library
Diphoton production in p{bar p} collisions at {radical}s = 1.8 TeV (open access)

Diphoton production in p{bar p} collisions at {radical}s = 1.8 TeV

We present measurements of the inclusive {gamma}{gamma} cross section (as a function of invariant mass and photon {epsilon}{sub {tau}}), in p{bar p} collisions at {radical}s = 1.8 TeV, made using the D0 detector at the Fermilab Tevatron collider. The next is leading order (NLO) QCD prediction is found to be in good agreement with the data. The effects of invariant mass and diphoton balance cuts, which test the next-to-leading order contributions to the cross section, are investigated. We also compare the distribution of {kappa}{sub {tau}} between samples of diphotons and highly electromagnetic jets, and find that the NLO QCD prediction models the shape of the {gamma}{gamma} {kappa}{sub {tau}} distribution quite well.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Inclusive muon and b quark production cross sections in p{bar p} collisions at {radical}s = 1.8 TeV (open access)

Inclusive muon and b quark production cross sections in p{bar p} collisions at {radical}s = 1.8 TeV

We report on the measurement of inclusive muon and b quark production by the D0 collaboration in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron Collider. The results represent a refined analysis of the previously published 1992--93 data. We measure the muon cross section due to b quark decays over the kinematic range 4 < p{sub T}{sup {mu}} < 30 GeV/c and {vert_bar}y{sup {mu}}{vert_bar} < 0.8. The extracted b quark production cross section is consistent with next to leading order QCD predictions within theoretical and experimental errors. The improved inclusive b quark production cross section is 6.9 {plus_minus}0.1(stat) {plus_minus} 2.2(syst) {mu}b for p{sub T}{sup {mu}} > 6 GeV/c and {vert_bar}y{sup b}{vert_bar} < 1.0.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Limits on the anomalous ZZ{gamma} and Z{gamma}{gamma} couplings in p{anti p} collisions at {radical}s = 1.8 TeV (open access)

Limits on the anomalous ZZ{gamma} and Z{gamma}{gamma} couplings in p{anti p} collisions at {radical}s = 1.8 TeV

The authors performed a direct search for the anomalous ZZ{gamma} and Z{gamma}{gamma} couplings by studying p{anti p} {yields} {ell}{ell}{gamma} + X, ({ell} = e, {mu}) events at {radical}s = 1.8 TeV with the D0 detector at the Fermilab Tevatron Collider. A fit to the transverse energy spectrum of the photon in the signal events, based on the data set corresponding to an integrated luminosity of 14.3 pb{sup {minus}1} (13.7 pb{sup {minus}1}) for the electron (muon) channel, yields the following 95% confidence level limits on the anomalous CP-conserving ZZ{gamma} couplings: {vert_bar}h{sub 30}{sup Z}{vert_bar} < 1.8 (h{sub 40}{sup Z} = 0), and {vert_bar}h{sub 40}{sup Z}{vert_bar} < 0.5 (h{sub 30}{sup Z} = 0), for a form-factor scale {Lambda} = 500 GeV. Limits for the Z{gamma}{gamma} couplings and CP-violating couplings are also discussed.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Rapidity correlations between high p{sub T} intermediate vector bosons and jets in {bar p}p collisions at {radical}s = 1.8 TeV (open access)

Rapidity correlations between high p{sub T} intermediate vector bosons and jets in {bar p}p collisions at {radical}s = 1.8 TeV

D{O} has used W {yields} e{nu} and Z {yields} e{sup +}e{sup -} events produced in association with a high p{sub T}, jet to examine the effects of strong radiative corrections. We have compared the primary jet pseudorapidity distribution, as a function of reconstructed W or Z boson rapidity to leading order (LO) and Next-to-Leading order (NLO) QCD Monte Carlo generators, as well as a model based on extended color dipoles. We find that the primary jet is more central than either LO or NLO expectations. None of the Monte Carlo programs does a good job of predicting the shape of the jet distributions as a function of intermediate vector bosons rapidity.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Rapidity gaps between jets at D0 (open access)

Rapidity gaps between jets at D0

Results are presented from an analysis of the particle multiplicity distribution between high transverse energy jets produced at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.8 Tev. Using the D0 detector, we examine the particle multiplicity distribution between the two highest transverse energy jets. For events with large rapidity separation, we observed a significant excess of events at low tagged-particle multiplicity which is consistent with a strongly interacting color-singlet exchange process.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Search for anomalous WW and WZ production at D0 (open access)

Search for anomalous WW and WZ production at D0

We present a preliminary result from a search for anomalous WW and WZ production in p{bar p} collisions at {radical}s = 1.8 TeV using p{bar p} {yields} e{nu}jj events observed during the 1992-1993 run of the Fermilab Tevatron collider. A fit to the p{sub T} spectrum of W(e{nu}) yields direct limits on the CP-conserving anomalous WW{gamma} and WWZ coupling parameters of -0.89 < {Delta}{kappa} < 1.07 ({lambda} = 0) and -0.66 < {lambda} < 0.67 ({Delta}{kappa} = 0) at the 95% confidence level, assuming that the WWZ coupling parameters are equal to the WW{gamma} coupling parameters, and a form factor scale {Lambda} = 1.5 TeV.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Search for light top squarks with the D{O} detector (open access)

Search for light top squarks with the D{O} detector

We present preliminary results of a search for pair produced top squarks, the supersymmetric partners to the top quark, under the assumption that the two-body decay {bar t}{sub 1} {yields} b{bar W}{sub 1} and three-body decay {bar t}{sub 1} {yields} bW{bar Z}{sub 1} are kinematically forbidden. This scenario is realized if {bar t}{sub 1} is considerably lighter than all other squarks as well as {bar W}{sub 1}, all {bar v}s, and the top quark. Such light top squarks will dominantly decay via {bar t}{sub 1} {yields} c{bar Z}{sub 1} yielding a signal of two acollinear jets with (E){sub T}. The data reported here were taken during the 1992-1993 run of the D0 detector at the Fermilab Tevatron p{bar p} collider operating at {radical}s = 1.8 TeV.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Search for W boson pair production in p{bar p} collisions at {radical}s = 1.8 TeV (open access)

Search for W boson pair production in p{bar p} collisions at {radical}s = 1.8 TeV

The results of a search for W boson pair production in p{bar p} collisions at {radical}s = 1.8 TeV with subsequent decay to dilepton (e{mu}, ee, and {mu}{mu}) channels are presented. One event is observed with an expected background of 0.56 {plus_minus} 0.13 events with an integrated luminosity of approximately 14 pb{sup {minus}1}. Assuming equal strengths for the WWZ and WW{gamma} gauge boson coupling parameters {kappa} and {lambda}, limits on the CP-conserving anomalous coupling constants are {minus}2.6 < {delta}{kappa} < 2.8 and {minus}2.1 {lambda} < 2.1 at the 95% confidence level.
Date: July 19, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Studies of topological distributions of the three- and four-jet events in {bar p}p collisions at {radical}s = 1800 GeV with the D0 detector (open access)

Studies of topological distributions of the three- and four-jet events in {bar p}p collisions at {radical}s = 1800 GeV with the D0 detector

The global topologies of three- and four-jet events produced in {bar p}p interactions are described. the three- and four-jet events are selected from data recorded by the D0 detector at the Tevatron Collider operating at a center-of-mass energy of {radical}s = 1800 GeV. the measured normalized distributions of various topological variables are compared with parton-level predictions of the tree- level QCD calculations. The parton-level QCD calculations are found to be in good agreement with the data. The studies also show that the topological distributions of the different subprocesses involving different numbers of quarks are very similar and reproduce the measured distributions well.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
A study of the strong coupling constant using W+ jets processes (open access)

A study of the strong coupling constant using W+ jets processes

The ratio of the number of W + 1 jet to W + 0 jet events is measured with the D0 detector using data from, the 1992--93 Tevatron Collider run. For the W {yields} e{nu} channel with a minimum jet E{sub T} cutoff of 25 GeV, the experimental ratio is 0.065 {+-} 0.003(stat) {+-} 0.007(sys). Next-to-Leading order QCD predictions for various parton distributions agree well with each other and are all over one standard deviation below the measurement. Varying the strong coupling constant {alpha}{sub s} in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy.
Date: July 1, 1995
Creator: Abachi, S.
System: The UNT Digital Library
Transverse energy distributions within jets in p{anti p} collisions at {radical}s = 1.8 TeV (open access)

Transverse energy distributions within jets in p{anti p} collisions at {radical}s = 1.8 TeV

The distribution of the transverse energy in jets has been measured in p{anti p} collisions at {radical}s = 1.8 TeV using the D0 detector at Fermilab. This measurement of the jet shape is made as a function of jet transverse energy in both the central and forward rapidity regions. Jets are observed to narrow both with increasing transverse energy and with increasing rapidity. Next-to-leading order partonic QCD calculations are compared to the data. Although the calculations qualitatively describe the data, they are shown to be very dependent on renormalization scale, parton clustering algorithm and jet direction definition and fail to consistently describe the data in all regions.
Date: July 1995
Creator: Abachi, S.
System: The UNT Digital Library
Single photon, photon-jet and diphoton production at DO (open access)

Single photon, photon-jet and diphoton production at DO

Results are described on the observation of isolated single photons by the DO detector at the Fermilab {anti p}p collider. The inclusive cross section has been measured for photons in the central rapidity region ({vert_bar} {eta} {vert_bar}< 0.9) above 10 GeV E{sub T}. Studies of jets recoiling against the single photon permit the measurement of the fundamental hard scattering cos{theta}* distribution. An analysis of the {eta} correlations between high-E{sub T} photons and the leading jet probes the gluon x distribution. Diphoton production measurements are used both as a test of QCD processes and as a search for resonant structure, including bosonic Higgs production.
Date: July 1, 1995
Creator: Abachi, S. & Collaboration, DO
System: The UNT Digital Library
Search for first and second generation leptoquarks at D0 (open access)

Search for first and second generation leptoquarks at D0

A search for first and second generation pair produced scalar leptoquarks has been done with the DO detector at Fermilab`s p{bar p} machine with {radical}s = 1.8 TeV. Leptoquarks are assumed to be strictly generational; for example, a first generation leptoquark couples only to the electron, its neutrino, and the u and d quarks. 95% C.L. mass limits of 133 GeV/c{sup 2} and 120 GeV/c{sup 2} for respective 100% and 50% decay branching ratios to electron plus quark for first generation scalar leptoquarks have been published. The preliminary results of a search for second generation scalar leptoquarks in the absence of a signal are mass limits of 111 GeV/c{sup 2} and 89 GeV/c{sup 2} for 100% and 50% decay branching ratios to muon plus quark. A feature of these mass limits is that they are independent of the unknown coupling of the leptoquark to leptons and quarks. The detection for e{sup +}e{sup {minus}} and e-p machines depends on the strength of this coupling.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B. & Abolins, M.
System: The UNT Digital Library
Search for fourth generation neutral heavy leptons (open access)

Search for fourth generation neutral heavy leptons

A search for fourth generation neutral heavy leptons ({nu}{sub 4}) in W decays was carried out the D0 detector at the Fermilab Tevatron at {radical}{bar s} = 1.8 TeV. The {nu}{sub 4} is assumed to be produced via mixing with the first generation neutrino only. We looked for a three electron final state event topology. The data used in this analysis represent 12.2 pb{sup {minus}1} taken during the 1992--1993 run. No candidates were found. We set a preliminary limit beyond the LEP limit for the considered mixing case on the {vert_bar}U{sub e4}{vert_bar}{sup 2} {minus} m{sub {nu}4} plane.
Date: July 1, 1995
Creator: Abachi, S.; Abbott, B.; Abolins, M. & Collaboration, D0
System: The UNT Digital Library
A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions (open access)

A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions

We report on the results of a search for the B{sub c} (b{bar c}) meson in the decay B{sub c}{sup +-} {yields} J/{psi} + {pi}{sup +-}. This search is guided by a control sample of decays of B{sub u} mesons to J/{psi} + K and uses {approx_equal} 75pb{sup -1} of data collected at the Collider Detector Facility (CDF) at Fermilab. The lifetime of the B{sub c} meson is unknown, so the 95% confidence level limit on {sigma} {center_dot} BR(B{sub c} {yields} {psi} + {pi})/{sigma} {center_dot} BR(B{sub u} {yields} {psi} + K) is obtained as a function of the B{sub c} lifetime.
Date: July 15, 1995
Creator: Abe, F.
System: The UNT Digital Library
Measurement of the B{sup +} and B{sup 0} meson lifetimes using exclusive B {yields} {psi}K decays at CDF (open access)

Measurement of the B{sup +} and B{sup 0} meson lifetimes using exclusive B {yields} {psi}K decays at CDF

The authors present recent CDF measurements of {tau}{sup +}, {tau}{sup 0}, and {tau}{sup +}/{tau}{sup 0} using exclusive B {yields} {psi}K decays, where B = B{sup +} or B{sup 0}, {psi} = J/{psi} or {psi}(2S), and K = K{sup +}, K*(892){sup 0}, K{sub S}{sup 0}, or K*(892){sup +}. The precision of these results is less than 10% and is nearly identical to that previously reported at LEP.
Date: July 1995
Creator: Abe, F.
System: The UNT Digital Library
Measurement of the mass of the B{sub s}{sup 0} meson in {bar p}p collisions at {radical}s = 1.8 TeV (open access)

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

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.
System: The UNT Digital Library
Measurement of the polarization in the decays B{sup 0} {yields} J/{psi}K*{sup 0} and B{sub s}{sup 0} {yields} J/{psi}{phi} (open access)

Measurement of the polarization in the decays B{sup 0} {yields} J/{psi}K*{sup 0} and B{sub s}{sup 0} {yields} J/{psi}{phi}

The authors report on a measurement of the longitudinal polarization fraction in the decay B{sup 0} {yields} J/{psi}K*{sup 0} using data collected with the Collider Detector at Fermilab. B{sup 0} mesons are reconstructed through the decay chain B{sup 0} {yields} J/{psi} K*{sup 0}, J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}}, K*{sup 0} {yields} K{sup +}{pi}{sup {minus}}. A sample of 65 {+-} 10 events is used to obtain the result {Lambda}{sub L}/{Lambda} = 0.65 {+-} 0.10 (stat) {+-} 0.04 (sys). The first measurement of {Lambda}{sub L}/{Lambda} in the decay B{sub s}{sup 0} {yields} J/{psi}{phi} is also presented.
Date: July 1995
Creator: Abe, F.
System: The UNT Digital Library
Observation of B{sup +} {yields} J/{psi}{pi}{sup +} (open access)

Observation of B{sup +} {yields} J/{psi}{pi}{sup +}

We report on the observation of the Cabibbo-suppresed mode B{sup +} J/{psi}{pi}{sup +}, with J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}}. Further, we calculate the relative branching ratio. BR(B{sup +} - J/{psi}{pi}{sup +})/BR(B{sup +} {yields} J/{psi}K{sup +}) and find a value of (4.9{sub {minus}1.7}{sup +}{plus_minus}1.1)%.
Date: July 1, 1995
Creator: Abe, F.
System: The UNT Digital Library
Production of J/{Psi} from {chi}{sub c} decays at CDF (open access)

Production of J/{Psi} from {chi}{sub c} decays at CDF

We have measured the fraction of J/{psi} originating from {chi}{sub c} states in p{bar p} collisions at {radical}s = 1.8 TeV in four bins of J/{psi} P{sub T}. The fraction in the inclusive CDF J/{psi} sample with P{sub T}{sup J/{psi}} > 4.0 GeV/c and {vert_bar}{eta}{sup J/{psi}}{vert_bar} < 0.6 is f{sub x}{sup J/{psi}} = 28.3{+-}1.6(stat){+-}6.8(syst)%. The fraction of J/{psi} from {chi}{sub c} not including contributions from B{yields}J/{psi}. X and B {yields} {chi}{sub c} X is f(Nob){chi}{sup J/{psi}} = 32.3{+-}2.0(stat){+-}8.5(syst)%. We have also found that directly produced {chi}{sub c}`s are produced in the ratio = {sigma}({chi}{sub c2}) over {sigma}({chi}{sub cl}) + {sigma}({chi}{sub c2})= 0.47{+-}0.08(stat){+-}0.02(syst.)
Date: July 1, 1995
Creator: Abe, F.
System: The UNT Digital Library
Search for the decay B{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}} (open access)

Search for the decay B{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}

The authors present a search for the decays B{sub d}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}} and B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}} using 17.8 pb{sup {minus}1} of data collected with the Collider Detector at Fermilab (CDF) during 1992--1993 data taking period. They find no B{sub d}{sup 0} candidates in a mass window of [5.205, 5.355] GeV/c{sup 2} and 1 B{sub s}{sup 0} candidate in a mass window of [5.300, 5.450] GeV/c{sup 2}. Normalizing to the measured cross-section {sigma} (B{sup +}) = 2.39 {+-} 0.54 {micro}b for p{sub t}(B) > 6 GeV/c and {vert_bar}y(B){vert_bar} < 1 and assuming {sigma}(B{sup +}) = {sigma}(B{sub d}{sup 0}) = 3{sigma}(B{sub s}{sup 0}), they find Br(B{sub d}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}) < 1.6 {times} 10{sup {minus}6} and Br(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}) < 8.4 {times} 10{sup {minus}6} at 90% confidence level. These limits are significant improvements of previous measurements.
Date: July 1, 1995
Creator: Abe, F.
System: The UNT Digital Library
Precision measurement of charge symmetry breaking in np elastic scattering at 347 MeV (open access)

Precision measurement of charge symmetry breaking in np elastic scattering at 347 MeV

Charge symmetry breaking in np elastic scattering at 347 MeV has been measured with high precision. From fits of the measured asymmetry curves over the angular range 53.4{degree} {le} {theta}{sub cm} {le} 86.9{degree}, the difference in the center-of-mass zero-crossing angles of the analyzing powers was determined to be 0.438{degree} {+-} 0.054{degree} (stat.) {+-} 0.051{degree} (syst.). Using the experimentally determined slope of the analyzing power, dA/d{theta} = ({minus}1.35 {+-} 0.05) {times} 10{sup {minus}2} deg{sup {minus}1}, this is equivalent to {Delta}A = [59 {+-} 7(stat.) {+-} 7(syst.) {+-} 2(syst.)] {times} 10{sup {minus}4}. Predictions of nucleon-nucleon interaction models based on meson exchange agree well with this result.
Date: July 1, 1995
Creator: Abegg, R.; Berdoz, A.R. & Birchall, J.
System: The UNT Digital Library
The evaluation of retrofit measures in a tall residential building (open access)

The evaluation of retrofit measures in a tall residential building

As part of a joint demonstration effort involving the US Department of Energy (DOE), the US Department of Housing and Urban Development (HUD), Boston Edison Company (BECo), and the Chelsea Housing Authority, Oak Ridge National Laboratory (ORNL) participated in the evaluation of energy and demand saving retrofits for a tall residential building located in Boston. The thirteen story all-electric building underwent window, lighting, and control renovations in December, 1992. annual energy consumption was reduced by 15% and peak demand fell by 17%. Hourly should building consumption data were available for the comparison of pre- and post- conditions and for calibration of a DOE-2.1D simulation model. The analysis found the window retrofit accounted for 90% of total energy savings and 95% of average demand savings, due to reductions in both conduction and infiltration. Benefits from lighting retrofits were low in cooling months and negligible in winter months due to the increase in the demand for electric resistance heating which was proportional to the reduction in lighting capacity. Finally, the simulation model verified that heating system controls had not been used as intended, and that the utility rate structure would not allow cost savings from the original control strategy. These results and …
Date: July 1, 1995
Creator: Abraham, M. M. & McLain, H. A.
System: The UNT Digital Library