Loomis, W.A.
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Observation of the top quark

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 74 (1995) 2632-2637, 1995.
Inspire Record 393099 DOI 10.17182/hepdata.42452

The DO collaboration reports on a search for the Standard Model top quark in pbar-p collisions at Sqrt(s)=1.8TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50pb-1. We have searched for t-tbar production in the dilepton and single-lepton decay channels, with and without tagging of b-quark jets. We observed 17 events with an expected background of 3.8+/-0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2.0E-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199~+19_21 (stat.)+/- 22 (syst.)GeV/c**2 and its production cross section to be 6.4 +/- 2.2 pb.

1 data table
Table 1

Cross section refers to top quark mass equal 199. (+19, -21, +- 22) GeV.


Observation of top quark production in anti-p p collisions

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 74 (1995) 2626-2631, 1995.
Inspire Record 393084 DOI 10.17182/hepdata.42453

We establish the existence of the top quark using a 67 pb^-1 data sample of Pbar-P collisions at Sqrt(s) = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). Employing techniques similar to those we previously published, we observe a signal consistent with t-tbar decay to WW b-bbar, but inconsistent with the background prediction by 4.8 sigma. Additional evidence for the top quark is provided by a peak in the reconstructed mass distribution. We measure the top quark mass to be 176 +/-8(stat) +/- 10(sys.) GeV/c^2, and the t-tbar production cross section to be 6.8 +3.6 -2.4 pb.

1 data table
Table 1

Cross section refers to top quark mass equal 176. (+- 8 +- 10) GeV.. Error contains both statistical and systematic uncertainty.


Measurement of the B meson differential cross-section, d sigma / d p(T), in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, M.G. ; Amendolia, S.R. ; et al.
Phys.Rev.Lett. 75 (1995) 1451-1455, 1995.
Inspire Record 393552 DOI 10.17182/hepdata.42432

This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$~{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B~{+}\rightarrow J/\psi K~{+}$ and $B~{0}\rightarrow J/\psi K~{*0}(892)$, where $J/\psi \rightarrow \mu~+\mu~-$ and $K~{*0} \rightarrow K~+ \pi~-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.

3 data tables
Table 1

Charged B meson cross section.

Table 2

Average B meson cross section (including charged and neutral).

Table 3

Total integrated B meson cross section above 6 GeV.


A Measurement of the ratio sigma x B (p anti-p ---> W ---> e neutrino) / sigma x B (p anti-p ---> Z0 ---> e e) in p anti-p collisions at s**(1/2) = 1800-GeV

The CDF collaboration Abe, F. ; Albrow, Michael G. ; Amendolia, S.R. ; et al.
Phys.Rev.D 52 (1995) 2624-2655, 1995.
Inspire Record 395439 DOI 10.17182/hepdata.42470

We present an analysis of data from p p¯ collisions at a center-of-mass energy of √s =1800 GeV. A measurement is made of the ratio R≡σB(p p¯→W→eν)/σB(p p¯→Z0→ee). The data represent 19.6 pg−1 collected by the Collider Detector at Fermilab during the 1992–1993 collider run of the Fermilab Tevatron. We find R=10.90±0.32(stat)±0.29(syst), and from this value we extract a measurement of the W→eν branching ratio Γ(W→eν)/Γ(W)=0.1094±0.0033(stat)±0.0031(syst). From this branching ratio we set a limit on the top quark mass of mt>62 GeV/c2 at the 95% confidence level. In contrast with direct searches for the top quark, this limit makes no assumptions about the allowed decay modes of the top quark. In addition, we use a calculation of the leptonic width Γ(W→eν) to obtain a value for the W total decay width: Γ(W)=2.064±0.060(stat)±0.059(syst) GeV.

1 data table
Table 1

The cross section ratio contains the branching ratio of W --> E NU and Z0 --> E+ E-. RE = PBAR P --> W+ X.


Production of strange B baryons decaying into Xi-+ - lepton-+ pairs at LEP

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys.C 68 (1995) 541-554, 1995.
Inspire Record 393792 DOI 10.17182/hepdata.52371

None

2 data tables
Table 1

HERE 'PRODUCTION FRACTION' IS PROBABILITY(BQ --> B-BARYON)*BR(B-BARYON --> XI- LEPTON- X). 'LEPTON' IS E OR MU.

Table 2

No description provided.


rivet Analysis
Properties of high mass multi - jet events at the Fermilab proton - anti-proton collider

The CDF collaboration Abe, F. ; Albrow, M.G. ; Amendolia, S.R. ; et al.
Phys.Rev.Lett. 75 (1995) 608-612, 1995.
Inspire Record 393345 DOI 10.17182/hepdata.52833

The properties of two-, three-, four-, five-, and six-jet events with multijet masses >600 GeV /c2 are compared with QCD predictions. The shapes of the multijet-mass and leading-jet-angular distributions are approximately independent of jet multiplicity and are well described by the NJETS matrix element calculation and the HERWIG parton shower Monte Carlo predictions. The observed jet transverse momentum distributions for three- and four-jet events discriminate between the matrix element and parton shower predictions, the data favoring the matrix element calculation.

19 data tables
Table 1

Exclusive 2-jet mass distribution.

Table 2

Exclusive 3-jet mass distribution.

Table 3

Exclusive 4-jet mass distribution.

More…

phi meson production from p anti-p collisions at s**(1/2) = 1.8-TeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Z.Phys.C 67 (1995) 411-416, 1995.
Inspire Record 405368 DOI 10.17182/hepdata.14115

Fermilab experiment E735 located at the CO intersection region of the\(\sqrt s= 1.8\) TeV\(p\bar p\) collider analysed over 900 Φ→K+K− events. Measured were the transverse momentum spectrum, the correlation between the average transverse momentum and the charged particle multiphcityNc, as well as the probability of Φ production per charged track,NΦ/Nc, versusNc. We have also made an estinate of the total inclusive cross section for Φ mesons,\(\sigma (p\bar p \to \phi X) = 7.3 \pm 2.2 mb\).

3 data tables
Table 1

Corrected phi meson transverse momentum distribution at rapidity = 0.

Table 2

Total inclusive cross section.

Table 3

Ratio of phi to rho0 production in high and low charged particle multiplicity events.


rivet Analysis
Measurement of phi meson parameters with CMD-2 detector at VEPP-2M collider

Akhmetshin, R.R. ; Aksenov, G.A. ; Anashkin, E.V. ; et al.
Phys.Lett.B 364 (1995) 199-206, 1995.
Inspire Record 406880 DOI 10.17182/hepdata.28437

Results of the measurement of the φ meson parameters with the general purpose detector CMD-2 at the upgraded e + e − collider VEPP-2M at Novosibirsk are presented. This is the first measurement of the four major φ decay modes in a single e + e − experiment. The results based on about 55,600 identified hadronic events are consistent with previous measurements, and have precision comparable to the current world average.

1 data table
Table 1

No description provided.


Production of charged particles, K0(s), K+-, p and Lambda in Z --> b anti-b events and in the decay of b hadrons

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 347 (1995) 447-466, 1995.
Inspire Record 392257 DOI 10.17182/hepdata.48180

A sample of events enriched in bb̄ quark pairs was selected in the data recorded by the DELPHI experiment at LEP during 1992 and 1993, by the presence of secondary decay vertices from short-lived particles. Using this sample, the average multiplicities of K s 0 , K ± , p(p̄), Λ( Λ ) and of charged particles in bb̄ events have been measured, distinguishing the component from fragmentation and the component coming from the decay of b-hadrons. The measurement of the average charge multiplicity in bb̄ events was used to compute the mean fractional beam energy carried by the primary b-hadron, and the difference in charged particle multiplicity between bb̄ events and light quark (uū, dd̄, ss̄) events.

9 data tables
Table 1

Event multiplicity in bottom events.

Table 2

Differential cross section for charged particles in BOTTOM tagged hemispheres.

Table 3

Differential cross section for charged particles in untagged hemispheres.

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Search for new particles decaying to dijets in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, M.G. ; Amendolia, S.R. ; et al.
Phys.Rev.Lett. 74 (1995) 3538-3543, 1995.
Inspire Record 392053 DOI 10.17182/hepdata.42387

We have used 19 pb**-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at 95% confidence level models containing the following new particles: axigluons with mass between 200 and 870 GeV, excited quarks with mass between 80 and 570 GeV, and color octet technirhos with mass between 320 and 480 GeV.

1 data table
Table 1

Here UNSPEC refers to axigluons, excited quarks, colour octet technirhos, ngauge bosons (W' and Z') and diquarks (D and Dc). M is the mass of the new particle (axigluon, q*, ...). Measurements are given to the 95% confidence limit.