HEPData Search

Showing 10 of 759 results

rivet Analysis
Studies of topological distributions of inclusive the three and four jet events in anti-P P collisions at s**(1/2) = 1800-GeV with the D0 detector

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Rev.D 53 (1996) 6000-6016, 1996.

Inspire Record 399364 DOI 10.17182/hepdata.11124

The global topologies of inclusive three-- and four--jet events produced in $\pp$ interactions are described. The three-- and four--jet events are selected from data recorded by the D\O\ detector at the Tevatron Collider operating at a center--of--mass energy of $\sqrt{s} = 1800$ GeV. The measured, normalized distributions of various topological variables are compared with parton--level predictions of 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. The parton shower Monte Carlo generators provide a less satisfactory description of the topologies of the three-- and four--jet events.

29 data tables match query

Table 1

The estimated systematic uncertainty is 6 PCT.

Table 2

The estimated systematic uncertainty is 6 PCT.

Table 3

The estimated systematic uncertainty is 6 PCT.

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rivet Analysis
First measurement of the quark to photon fragmentation function

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.

Z.Phys.C 69 (1996) 365-378, 1996.

Inspire Record 398193 DOI 10.17182/hepdata.12261

Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon productioninside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energyz≥0.7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function,D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions toD(z) obtained from anO(ααs) QCD calculation, the unknown non-perturbative component ofD(z) is then determined at highz. Provided due account is taken of hadronization effects nearz=1, a good description of the other event topologies is then found.

16 data tables match query

Table 1

2-jet events. Variable Z has been defined as E(gamma)/(E(gamma)+E(had)), where E(gamma) is the energy of the hard photon in 'photon-jet', E(had) is the energy of the rest hadrons in jet. Ycut is jet resolution parameter (see paper).

Table 2

Table 3

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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 match query

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.

Neutrino production of same sign dimuons at the Fermilab Tevatron

Sandler, P.H. ; Kinnel, T.S. ; Smith, W.H. ; et al.

Z.Phys.C 57 (1993) 1-12, 1993.

Inspire Record 32390 DOI 10.17182/hepdata.14493

The rate of neutrino- and antineutrino-induced prompt same-sign dimuon production in steel was measured using a sample of μ−μ− events and 25 μ+μ+ events withPμ>9 GeV/c, produced in 1.5 millionvμ and 0.3 million$\overline {v_\mu}$ induced charged-current events with energies between 30 GeV and 600 GeV. The data were obtained with the Chicago-Columbia-Fermilab-Rochester (CCFR) neutrino detector in the Fermilab Tevatron Quadrupole Triplet Neutrino Beam during experiments E 744 and E 770. After background subtraction, the prompt rate of same-sign dimuon production is (0.53±0.24)×10−4 pervμ charged-current event and (0.52±0.33)×10−4 per$\overline {v_\mu}$ charged-current event. The kinematic distributions of the same-sign dimuon events after background subtraction are consistent with those of the non-prompt background due to meson decays in the hadron shower of a charged-current event. Calculations ofc$\bar c$ gluon bremsstrahlung, based on improved measurements of the charm mass parameter and nucleon structure functions by the CCFR collaboration, yield a prompt rate of (0.09±0.39)×10−4 pervμ charged-current event. In this case,c$\bar c$ gluon bremsstrahlung is probably not an observable source of prompt same-sign dimuons.

2 data tables match query

Table 1

Rate of dimuon production per charged current event.

Table 2

Rate of dimuon production per charged current event.

Study of the e+ e- ---> Z gamma gamma ---> q anti-q gamma gamma process at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.

Phys.Lett.B 505 (2001) 47-58, 2001.

Inspire Record 552996 DOI 10.17182/hepdata.13379

The process e^+e^- -> Z gamma gamma -> q q~ gamma gamma is studied in 0.5 fb-1 of data collected with the L3 detector at centre-of-mass energies between 130.1 GeV and 201.7 GeV. Cross sections are measured and found to be consistent with the Standard Model expectations. The study of the least energetic photon constrains the quartic gauge boson couplings to -0.008 GeV-2 < a_0/\Lambda^2 < 0.005 GeV-2 and -0.007 GeV-2 < a_c/\Lambda^2 < 0.011 GeV-2, at 95% confidence level.

5 data tables match query

Table 1

No description provided.

Table 2

The results are presented for more more restrictive phase space.

Table 3

CONST(NAME=LAMBDA_NEW) is New Physics scale. COUPLING(NAME=A0,AC) are quartic gauge boson couplings of the effective Lagrangians (see paper for details).

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TOTAL CROSS-SECTION OF HADRON PHOTOPRODUCTION ON Be, C, H2O AND Al NUCLEI IN THE ENERGY RANGE E (gamma) = 200-MeV TO 900-MeV

Arakelian, E.A. ; Bayatian, G.L. ; Grigorian, N.K. ; et al.

EFI-730-45-84-YEREVAN, 1984.

Inspire Record 206946 DOI 10.17182/hepdata.2700

None

2 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Coincidence electroproduction of single neutral pions in the resonance region at q 2 = 0.5 (GeV/ c ) 2

Latham, A. ; Allison, J. ; Booth, I. ; et al.

Nucl.Phys.B 156 (1979) 58-92, 1979.

Inspire Record 1392686 DOI 10.17182/hepdata.836

Data are presented for the reaction ep → ep π 0 at a nominal four-momentum transfer squared of 0.5 (GeV/ c ) 2 . The data were obtained using an extracted electron beam from NINA and two magnetic spectrometers for coincidence detection of the electron and proton. Details are given of the experimental method and the results are given for isobar masses in the range 1.19 – 1.73 GeV/ c 2 .

21 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A Study of D*+- production in Z0 decays

The OPAL collaboration Alexander, G. ; Allison, J. ; Allport, P.P. ; et al.

Phys.Lett.B 262 (1991) 341-350, 1991.

Inspire Record 315060 DOI 10.17182/hepdata.9272

In this paper an investigation of the production of D ∗ ± mesons produced in e + e − collisions at energies around the Z 0 pole is presented. Based on 115 D ∗ ± mesons with x D∗  2E D ∗ /E cm > 0.2 the properties of D ∗ mesons produced in the reaction Z 0 → c c are studied. Fixing the yield and the fragmentation function of bottom quarks to the values obtained at LEP using lepton tags, and average energy fraction of the D ∗ ± mesons from primary charmed quarks of 〈x c → D ∗ 〉 = 0.52 ± 0.03 +- 0.01 is found and Γ z 0 →c c = (323 ± 61 ± 35) MeV is determined. The first error is the combined statistical and systematic error from this experiment, and the second the total error from other sources.

2 data tables match query

Table 1

FD denotes the fraction of D* mesons from primary charmed quarks, derived from the fit (see text).

Table 2

No description provided.

Properties of multi - hadronic events with a final state photon at s**(1/2) = M (Z0)

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 54 (1992) 193-210, 1992.

Inspire Record 322027 DOI 10.17182/hepdata.14650

The properties of final state photons in multihadronic decays of theZ0 and those of the recoiling hadronic system are discussed and compared with theoretical expectations. The yield of two and three jet events with final state photons is found to be in good agreement with the expectation from a matrix element calculation ofO(ααs. Uncertainties in the interpretation of the theoretical calculation do not yet permit a final assessment of events with just one reconstructed jet. Comparing the rates of two jet events with a photon to those of three jet events in the inclusive multihadronic sample, the strong coupling constant in second order is determined asαs$(M_{Z^0 } )$=0.122±0.010, taking into account only the statistical and experimental systematic errors. It is found that an abelian model of the strong interaction does not describe the data. The comparison of the total yield and the jet rates with QCD shower programs shows better agreement with the ARIADNE model than with the JETSET model. Both programs are found to describe well the photon properties and the properties of the residual hadronic event.

4 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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