Achasov, M.N.
hep-ex
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DOUBLE PROMPT PHOTON PRODUCTION AT HIGH TRANSVERSE MOMENTUM BY pi- ON PROTONS AT 280-GeV/c

The WA70 collaboration Bonvin, E. ; Bopp, R. ; Carroll, L.J. ; et al.
Z.Phys.C 41 (1989) 591, 1989.
Inspire Record 265091 DOI 10.17182/hepdata.15470

A search for pairs of highpT prompt photons produced in hydrogen by a 280 GeV/c incidentπ- beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forpT>3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of αs is also presented.

2 data tables match query
Table 1

PT is the transverse momentum of either of the two photons.

Table 2

PT is the transverse momentum of either of the two photons.


Measurements of the b anti-b production cross-section and forward backward asymmetry at center-of-mass energies above the Z pole at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 485 (2000) 71-84, 2000.
Inspire Record 527337 DOI 10.17182/hepdata.49963

The measurements of Rb = sigma(e+e- -> bb~)/sigma(e+e- -> qq~) and of the b quark forward-backward charge asymmetry, A^b_fb, at centre-of-mass energies above the Z pole are described. The measurement of Rb is performed at \root{s} between 130 and 189 GeV using a b-tagging method that exploits the relatively large decay length of b-hadrons. The measurement of A^b_fb is performed using the large statistics event sample collected at \root{s}=189 GeV with a lepton-tag analysis based on the selection of prompt muons and electrons. The results at \root{s}=189 GeV are: Rb = 0.163 +/- 0.013 (stat.) +/- 0.005 (syst.), A^b_fb = 0.61 +/- 0.18 (stat.) +/- 0.09 (syst.).

2 data tables match query
Table 1

No description provided.

Table 2

No description provided.


Hard photon production and tests of QED at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 475 (2000) 198-205, 2000.
Inspire Record 513397 DOI 10.17182/hepdata.48965

The total and differential cross sections of the process e+e- -> n gamma with n >= 2 are measured using data collected by the L3 experiment at centre-of-mass energies of \sqrt{s}=183 and 189 GeV. The results are in agreement with the Standard Model expectations. Limits are set on deviations from QED, contact interaction cut-off parameters and masses of excited electrons.

2 data tables match query
Table 1

Measured cross section.

Table 2

Measured differential cross sections corrected for efficiency and additional photons as a function of cos(theta) where theta is the polar angle of the event defined as. cos(theta)=ABS((sin(theta1-theta2)/2)/(sin(theta1+theta2)/2)).


Search for anomalous couplings in the Higgs sector at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 489 (2000) 102-114, 2000.
Inspire Record 531571 DOI 10.17182/hepdata.49878

We search for a Higgs particle with anomalous couplings in the e+e- -> H gamma, e+e- -> HZ and e+e- -> He+e- processes with the L3 detector at LEP. We explore the mass range 70GeV < m_H < 170GeV using 176pb^-1 of integrated luminosity at a center-of-mass energy of \sqrt{s} = 189GeV. The Higgs decays H -> bb, H -> gamma gamma and H -> Z gamma are considered in the analysis. No evidence for anomalous Higgs production is found. This is interpreted in terms of limits on the anomalous couplings d, d_B, Delta g_1^Z and Delta kappa_gamma. Limits on the Gamma(H -> gamma gamma) and Gamma(H -> Z gamma) partial widths in the explored Higgs mass range are also obtained.

3 data tables match query
Table 1

The cross section times BR(HIGGS --> 2GAMMA).

Table 2

The cross section times BR(HIGGS --> BQ BQBAR).

Table 3

The cross section times BR(HIGGS --> Z GAMMA).


Measurement of cross-sections and leptonic forward - backward asymmetries at the z pole and determination of electroweak parameters

The L3 collaboration Acciarri, M. ; Adam, A. ; Adriani, O. ; et al.
Z.Phys.C 62 (1994) 551-576, 1994.
Inspire Record 374696 DOI 10.17182/hepdata.48198

We report on the measurement of the leptonic and hadronic cross sections and leptonic forward-backward asymmetries at theZ peak with the L3 detector at LEP. The total luminosity of 40.8 pb−1 collected

28 data tables match query
Table 1

Results from 1990 data. Additional systematic uncertainty of 0.3 pct.

Table 2

Results from 1991 data. Additional systematic uncertainty of 0.15 pct.

Table 3

Results from 1992 data. Additional systematic uncertainty of 0.15 pct.

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Search for anomalous Z Z gamma and Z gamma gamma couplings in the process e+ e- ---> Z gamma at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 489 (2000) 55-64, 2000.
Inspire Record 527338 DOI 10.17182/hepdata.49970

We search for anomalous trilinear gauge couplings in the ZZgamma and Zgammagamma vertices using data collected with the L3 detector at LEP at a centre-of-mass energy \sqrt{s}=189 GeV. No evidence is found and limits on these couplings and on new physics scales are derived from the analysis of the process e+e- -> Zgamma.

2 data tables match query
Table 1

No description provided.

Table 2

See text for Z(GAMMA) anomalous coupling definitions.


Measurement of charged-particle multiplicity distributions and their H(q) moments in hadronic Z decays at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 577 (2003) 109-119, 2003.
Inspire Record 565148 DOI 10.17182/hepdata.49796

The charged-particle multiplicity distribution is measured for all hadronic events as well as for light-quark and b-quark events produced in e+e- collisions at the Z pole. Moments of the charged-particle multiplicity distributions are calculated. The H moments of the multiplicity distributions are studied, and their quasi-oscillations as a function of the rank of the moment are investigated.

6 data tables match query
Table 1

Moments of the charged particle multiplicity distribution with KOS and LAMBDA decay for all events.

Table 2

Moments of the charged particle multiplicity distribution without KOS and LAMBDA decay for all events.

Table 3

Moments of the charged particle multiplicity distribution with KOS and LAMBDA decay for light quark events.

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