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A Measurement of the Space - Like Pion Electromagnetic Form-Factor

The NA7 collaboration Amendolia, S.R. ; Arik, M. ; Badelek, B. ; et al.

Nucl.Phys.B 277 (1986) 168, 1986.

Inspire Record 228132 DOI 10.17182/hepdata.33611

The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/ c ) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r 2 π 〉 = 0.438±0.008 fm 2 .

1 data table

Table 1

No description provided.

A Study of the Production of Two Direct Photons in $p p$ Collisions at the {CERN} {ISR}

The Axial Field Spectrometer collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.

Z.Phys.C 32 (1986) 491-497, 1986.

Inspire Record 228954 DOI 10.17182/hepdata.15834

We have studied the processpp→γγ+X at$\sqrt s= 63 GeV$ GeV in the central rapidity region. We report a positive signal at 96% C.L., a ratio γγ/e+e−=4.0±3.0 when the transverse momentum of each photon is above 2 GeV/c, and a cross-sectiondσ/dydMγγ=(5.5±2.7)×10−34 cm2/GeV when |y|<0.5,4<Mγγ<6 GeV.

1 data table

Table 1

No description provided.

Measurement of the Photon Structure Function f(2)Gamma at Q2 from 7-GeV/c2 to 70-GeV/c**2

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gerhards, R. ; et al.

Z.Phys.C 31 (1986) 527, 1986.

Inspire Record 228251 DOI 10.17182/hepdata.15858

We have measured the processe+e−→e+e−+hadrons, where one of the scattered electrons was detected at large angles, withQ2 ranging from 7 to 70 (VeV/c)2. The photon structure functionF2γ(x, Q2) was determined at an averageQ2 of 23 (GeV/c)2. The measurements were compared to theoretical predictions of the Quark Parton Model and Quantum Chromodynamics. In both models a hadronic part was added. Within the errors the data are in agreement with the QPM using quark masses of 300 MeV/c2 for the light quarks. The data also agree with a QCD calculation including higher order corrections. A fit yielded a$\Lambda _{\overline {MS} } $ value of 140−65+190 MeV, where the errors include statistical and systematic uncertainties.

1 data table

Table 1

No description provided.

Vector Meson Production in the Final State $K^+ K^- \pi^+ \pi^-$ Photon-photon Collisions

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gerhards, R. ; et al.

Z.Phys.C 32 (1986) 11, 1986.

Inspire Record 228250 DOI 10.17182/hepdata.15846

Vector meson production is studied in the reaction γγ→K+K−π+π−. A clear Φ(1020) signal is seen in theK+K− mass distribution and aK*0 (890) signal is visible in theK±π∓ one. Both do not seem to be strongly correlated with quasi two body final states. Cross sections for the processes γγ→K+K−π+π−, γγ→Φπ+π−, γγ→K+0K±π∓ and upper limits for the production of Φp, ΦΦ andK*0$\overline {K^{ * 0} } $ are given as function of the invariant γγ mass.

5 data tables

Table 1

No description provided.

Table 2

First data point is sum of (K* K PI) and (K* AK*).

Table 3

Non resonant phase space.

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Characteristics of Charm Production by 400-{GeV} Protons

Duffy, M.E. ; Fanourakis, G.K. ; Loveless, R.J. ; et al.

Phys.Rev.Lett. 57 (1986) 1522, 1986.

Inspire Record 229849 DOI 10.17182/hepdata.20206

In a beam-dump experiment at Fermilab the cross section for charm-particle production has been deduced from a measurement of the prompt neutrino flux. The reaction cross section, if we assume only DD¯ and the dependence on atomic weight A0.75, is 57.2 ± 2.9 ± 8.5 μb/nucleon and the dependence on Feynman x and transverse momentum is EDd3σdpD3∝(1−x)3.2e−1.5p⊥ (p⊥ in GeV/c). The data are consistent with as much as 40% diffractive production of ΛcD¯.

2 data tables

Table 1

Assuming only (D AD) production and branching ratio BR(D--> NU) = 0.101.

Table 2

Assuming both (D AD) and (LAMBDA/C AD) production.

A Precision Measurement of sin**2theta(W) from Semileptonic Neutrino Scattering

Abramowicz, H. ; Belusevic, R. ; Blondel, A. ; et al.

Phys.Rev.Lett. 57 (1986) 298, 1986.

Inspire Record 228111 DOI 10.17182/hepdata.20208

The ratio Rν of the neutral- to charged-current cross sections of neutrinos in iron has been measured in an exposure of the CERN-Dortmund-Heidelberg-Saclay neutrino detector to a 160-GeV/c neutrino narrow-band beam at the CERN Super Proton Synchrotron. The result is Rν=0.3072±0.0025(stat)±0.0020(syst), for hadronic energy greater than 10 GeV. The electroweak mixing parameter is sin2θW=0.225±0.005(expt)±0.003(theor)+0.013(mc−1.5 GeVc2), where mc is the charm-quark mass.

1 data table

Table 1

No description provided.

Test of Charge Symmetry in Neutron - Proton Elastic Scattering at 477-{MeV}

Abegg, R. ; Bandyopadhyay, D. ; Birchall, J. ; et al.

Phys.Rev.Lett. 56 (1986) 2571, 1986.

Inspire Record 228239 DOI 10.17182/hepdata.20237

An experiment resulting in the first measurement of the isospin-mixing, charge-symmetry-violating component of the n−p interaction has been performed. The experiment determined the difference in the angles of the zero crossing of the neutron and proton analyzing powers An and Ap at 477 MeV. In terms of the laboratory scattering angle of the neutron, the measured difference is θ0n(An)−θ0n(Ap)=+0.13° ±0.06° (±0.03°), where the second error is a worst-case estimate of systematic error. The resulting difference in the analyzing powers at the zero-crossing angle is An−Ap=+0.0037 ±0.0017 (±0.0008).

1 data table

Table 1

No description provided.

DIJET PRODUCTION CROSS-SECTION AND FRAGMENTATION OF JETS PRODUCED IN P P COLLISIONS AT S**(1/2) = 63-GEV

The AXIAL FIELD SPECTROMETER collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.

Z.Phys.C 30 (1986) 27-43, 1986.

Inspire Record 221571 DOI 10.17182/hepdata.16017

We present stdies of events triggered on two high-pT jets, produced inpp collisions at the CERN Intersecting Storage Rings (ISR) at$\sqrt s $=63 GeV, using a large solid angle calorimeter. The cross-section for producing two jets is measured in the dijet mass range 17–50 GeV/c2. A high-statistics sample of dijet events, where each jet has transverse energy above 10 GeV, is used to study the structure of jets and the associated event. We find the longitudinal fragmentation function to be similar to that of jets emerging frome+e− collisions but considerably harder than that observed at the Super Proton Synchrotron (SPS)$p\bar p$ Collider. A steepening of the fragmentation function is observed when increasing the jet energy. Studies of the charge distribution in jets show that these predominantly originate from fragmenting valence quarks. The transverse energy and particle flows are presented as functions of the azimuthal distance from the jet axis.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

FRAGMENTATION FUNCTION FOR ET(JET) > 10 GEV.