Max results
Sort by Reverse order

Showing 10 of 10000 results

Date

Measurement of the top quark pair production cross section in the all-jets decay channel

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.Lett. 83 (1999) 1908-1913, 1999.
Inspire Record 494099 DOI 10.17182/hepdata.42119

We present a measurement of tbar-t production using multijet final states in pbar-p collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity of 110.3 pb(-1). The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the tbar-t production cross section, and yields a cross section of 7.1 +/- 2.8(stat.) +/- 1.5(syst.) pb, assuming a top quark mass of 172.1 GeV/c^(2). Combining this result with previous D0 measurements, where one or both of the W bosons decay leptonically, gives a tbar-t production cross section of 5.9 +/- 1.2(stat) +/- 1.1(syst) pb.

1 data table
Table 1

No description provided.


Measurement of the carbon analyzing power in the momentum range 1.36-GeV/c to 2.02-GeV/c.

Alekseev, I.G. ; Budkovsky, P.E. ; Kanavets, V.P. ; et al.
Phys.Atom.Nucl. 62 (1999) 2024-2030, 1999.
Inspire Record 515065 DOI 10.17182/hepdata.39979

None

12 data tables
Table 1

THE CARBON THICKNESS 4.9 G/CM**2.

Table 2

THE CARBON THICKNESS 19.4 G/CM**2.

Table 3

THE CARBON THICKNESS 36.5 G/CM**2.

More…

Differential cross section for the reaction C-12(d,p)X at a primary momentum of 9-GeV/c and its tensor and vector analyzing powers.

Azhgirei, L.S. ; Arkhipov, V.V. ; Afanasev, S.V. ; et al.
Phys.Atom.Nucl. 62 (1999) 1673-1686, 1999.
Inspire Record 513982 DOI 10.17182/hepdata.17059

None

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Emission of light fragments in O-16 p interactions at a momentum of 3.25-GeV/c per projectile nucleon.

Glagolev, V.V. ; Gulamov, K.G. ; Lipin, V.D. ; et al.
Phys.Atom.Nucl. 62 (1999) 1388-1392, 1999.
Inspire Record 512749 DOI 10.17182/hepdata.17086

None

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Measurement of the neutron electric form factor G(E,n) in the quasifree H-2(e(pol.),e' n(pol.))p reaction.

Ostrick, M. ; Herberg, C. ; Andresen, H.G. ; et al.
Phys.Rev.Lett. 83 (1999) 276-279, 1999.
Inspire Record 506748 DOI 10.17182/hepdata.19444

The electric form factor of the neutron GE,n has been measured in the quasifree 2H(e→,e′n→)p reaction using the 855 MeV polarized cw electron beam of the Mainz Microtron MAMI. The polarization of the scattered neutrons was analyzed in a polarimeter consisting of two walls of plastic scintillators. The precession of the neutron spin in a magnetic field was used for the first time to circumvent the measurement of the effective analyzing power of the polarimeter and the beam polarization. In this way GE,n could be determined with little model dependence and experimental uncertainties. The result GE,n(0.34GeV2/c2)=0.0611±0.0069stat({+0.0069}{−0.0055})syst is larger than previously assumed.

1 data table
Table 1

No description provided.


Deep-subthreshold eta and pi0 production probing pion dynamics in the reaction Ar + Ca at 180-A-MeV.

Martinez, G. ; Charbonnier, Y. ; Aphecetche, L. ; et al.
Phys.Rev.Lett. 83 (1999) 1538-1541, 1999.
Inspire Record 508818 DOI 10.17182/hepdata.19447

We report on a measurement of subthreshold η and π0 mesons in the reaction Ar+Ca at 180A MeV. We find that the ratio of the η to π0 meson-production cross section is more than a factor of 20 smaller than the one expected from threshold-energy scaling of meson production. In addition, the multiplicity of high mt π0 increases faster with the centrality of the reaction than the multiplicity of the bulk of π0 mesons. This behavior is explained by the rescattering of π mesons in nuclear matter at the origin of most energetic particles.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


New measurement of the anomalous magnetic moment of the positive muon

Carey, R.M. ; Earle, W. ; Efstathiadis, E. ; et al.
Phys.Rev.Lett. 82 (1999) 1632-1635, 1999.
Inspire Record 500172 DOI 10.17182/hepdata.19493

The muon anomalous magnetic moment has been measured in a new experiment at Brookhaven. Polarized muons were stored in a superferric ring, and the angular frequency difference, ωa, between the spin precession and orbital frequencies was determined by measuring the time distribution of high-energy decay positrons. The ratio R of ωa to the Larmor precession frequency of free protons, ωp, in the storage-ring magnetic field was measured. We find R=3.707220(48)×10−3. With μμ/μp=3.18334547(47) this gives aμ+=1165925(15)×10−9 ( ±13ppm), in good agreement with the previous CERN measurements for μ+ and μ− and of approximately the same precision.

1 data table
Table 1

The anomalous g value is related to the gyromagnetic ratio by MOM(NAME=ANOMALOUS MAGNETIC) = (G-2)/2. The beam momentum spread is about 1 PCT.


Analyzing powers and partial wave decomposition of p n --> p p((1)S(0)) pi- at low energies.

Hahn, H. ; Duncan, F.A. ; Aclander, J. ; et al.
Phys.Rev.Lett. 82 (1999) 2258-2261, 1999.
Inspire Record 500174 DOI 10.17182/hepdata.19495

Analyzing powers for p→n→pp(S01)π− were measured at beam energies 353, 404, and 440 MeV by extracting the quasifree process from p→d→pppπ−. Partial wave amplitude analysis yields a significant contribution from the isospin 1, s-wave channel. This contribution is relatively much larger than that expected from theoretical models which have been successful in describing the isospin 1, s-wave channel behavior of pp→ppπ0 cross sections at threshold.

3 data tables
Table 1

Axis error includes +- 0.0/0.0 contribution (?////).

Table 2

Axis error includes +- 0.0/0.0 contribution (?////).

Table 3

Axis error includes +- 0.0/0.0 contribution (?////).


Inclusive spectra and large-angle correlations of pions and protons in pi- Be collisions at 43-GeV/c.

The SIGMA-AYAKS collaboration Kartasheva, V.G. ;
Phys.Atom.Nucl. 62 (1999) 1370-1377, 1999.
Inspire Record 512747 DOI 10.17182/hepdata.17090

None

21 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

rivet Analysis
Precise measurement of the total hadronic cross section in e+ e- annihilation at s**(1/2) = 57.77-GeV.

The VENUS collaboration Yusa, K. ; Hamasaki, H. ; Mori, S. ; et al.
Phys.Lett.B 447 (1999) 167-177, 1999.
Inspire Record 500179 DOI 10.17182/hepdata.5548

The total hadronic cross section in e + e − annihilation has been measured at s = 57.77 GeV using 290 pb −1 data sample collected with the VENUS detector at KEK TRISTAN. The cross section obtained is 140.3 ±1.8 pb for s ′/ s ≥0.5, where s ′ is the square of the invariant mass of the final state hadrons. The present result together with the recent results from the LEP collaborations is used to determine the hadronic γ − Z 0 interference parameter, j tot had , to be 0.196±0.083. The result is in good agreement with the Standard Model prediction of 0.220.

2 data tables
Table 1

The statistical and systematic errors are added in quadrature.

Table 2

No description provided.