Date

Determination of the Real Part of the Isospin Even Forward Scattering Amplitude of Pion Nucleon Scattering at 55-{MeV} as a Test of Low-energy Quantum Chromodynamics

Wiedner, U. ; Goring, K. ; Jaki, J. ; et al.
Phys.Rev.Lett. 58 (1987) 648-650, 1987.
Inspire Record 246624 DOI 10.17182/hepdata.20153

The real part of the isospin-even forward-scattering amplitude of pion-nucleon scattering has been determined at a pion energy of Tπ=55 MeV by measurement of the elastic scattering of positive and negative pions on protons within the Coulomb-nuclear interference region. The value confirms the prediction of the Karlsruhe-Helsinki phase-shift analysis for that energy. These phases have been used to determine the σ term of pion-nucleon scattering by means of dispersion relations, resulting in a value for σ which is in contradiction with chiral perturbation theory of QCD.

1 data table

PI- P cross sections normalised to the Coulomb cross section taken from the Karlesruhe-Helsinki phase shift analysis (R. Koch, E. Pietarinen (NP A336(80)331).


Forward and Transverse Energy Distributions in Oxygen Induced Reactions at 60-agev and 200-agev

The WA80 collaboration Albrecht, R. ; Awes, T.C. ; Baktash, C. ; et al.
Phys.Lett.B 199 (1987) 297-303, 1987.
Inspire Record 254598 DOI 10.17182/hepdata.30059

Results are presented from reactions of 60 A GeV and 200 A GeV 16 O projectiles with C, Cu, Ag, and Au nuclei. Energy spectra measured at zero degrees and transverse energy distributions in the pseudorapidity range from 2.4 to 5.5 are shown. The average transverse energy per participant is found to be nearly independent of target mass. Estimates of nuclear stopping and of attained energy densities are made.

1 data table

STOPPING POWER IS THE QUANTITY GIVEN IN THIS TABLE. IT IS DEFINED AS ( D(ET(EXP)/D(ETA) / D(ET(THEORY)/D(ETA) ) AND THE DENOMINATOR IS TAKEN TO BE 0.5*E(HADRON IN CM). ETA IS THE PSEUDO-RAPIDITY.


Strangeness Suppression and Inclusive $\phi$ and $K^*$0 Production in $K^+ P$ Interactions at 250-{GeV}/c

The EHS - NA22 collaboration Adamus, M. ; Agababyan, N.M. ; Ajinenko, I.V. ; et al.
Phys.Lett.B 198 (1987) 427-432, 1987.
Inspire Record 254217 DOI 10.17182/hepdata.30075

We present inclusive ¶ and K *0 (892) cross sections and Feynman x -spectra in K + p collisions at 250 GeV/ c . In the K + fragmentation region, x > 0.2, the ratio of ¶ to K *0 (892) is used to estimate the strangeness suppression factor λ , with the result γ =0.17 ± 0.02 (stat ± 0.01 (syst). We see no evidence for an energy dependence of λ in the CM energy range 7.8 ≤ s ≤21.7 GeV.

4 data tables

RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.

RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.

RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.

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A Comparison of Inclusive $\rho^0$, $\rho^+$ and $\Omega$ Production in $K^+ P$ Interactions at 250-{GeV}/c

The EHS/NA22 collaboration Adamus, M. ; Agababyan, N.M. ; Ajinenko, I.V. ; et al.
Phys.Lett.B 198 (1987) 292-296, 1987.
Inspire Record 254609 DOI 10.17182/hepdata.30078

Inclusive data are presented on ϱ 0 ,ϱ + and ω produced in k + p interactions at 250 GeV/ c , for ϱ + and ω for the first time in K + p experiment. In the forward CM hemisphere, the ϱ + , ϱ 0 and ω differential production rates are equal within errors, and remarkably similar to muon-inelastic scattering data on ϱ 0 and ω at 280 GeV/ c .

1 data table

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The Production of Prompt Positrons at Low Transverse Momentum Increases With the Square of the Associated Charged Multiplicity

The Axial Field Spectrometer collaboration Åkesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.
Phys.Lett.B 192 (1987) 463-470, 1987.
Inspire Record 244887 DOI 10.17182/hepdata.30156

We have measured the production of prompt positrons in pp collisions at √ s = 63 GeV and y = 0 in the p T interval 0.12< p T <1.0 GeV/c. The results indicate that the production of positrons at low p T (<0.4 GeV/ c ) is proportional to the square of the mean multiplicity in the central region | y | < 1. Such a quadratic dependence is not expected from final-state sources such as hadronic bremsstrahlung or hadronic decays, but is natural in models where low mass electron pairs are produced by interactions of constituents created during the collision.

3 data tables

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A Measurement of the Proton Structure Functions From Neutrino Hydrogen and Anti-neutrino Hydrogen Charged Current Interactions

The Birmingham-CERN-Imperial Coll.-MPI(Munich)-Oxford-University Coll. collaboration Jones, G.T. ; Jones, R.W.L. ; Kennedy, B.W. ; et al.
Z.Phys.C 44 (1989) 379-384, 1989.
Inspire Record 252341 DOI 10.17182/hepdata.15358

Within the framework of the quark-parton model, the quark and anti-quark structure functions of the proton have been measured by fitting them to the distributions of the events in the Bjorkeny variable. The data used form the largest sample of neutrino and antineutrino interactions on a pure hydrogen target available, and come from exposures of BEBC to the CERN wide band neutrino and antineutrino beams. It is found that the ratiodv/uv of valence quark distributions falls with increasing Bjorkenx. In the context of the quark-parton model the results constrain the isospin composition of the accompanying diquark system. Models involving scattering from diquarks are in disagreement with the data.

3 data tables

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Single Diffraction Dissociation in $\pi^+ p$ and $K^+ p$ Interactions at 250-{GeV}/$c$

The EHS/NA22 collaboration Adamus, M. ; Azhinenko, I.V. ; Almeida, F.M.L., Jr. ; et al.
Z.Phys.C 39 (1988) 301, 1988.
Inspire Record 254506 DOI 10.17182/hepdata.15646

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1 data table

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Limit on the Decay D0 $\to e^\pm \mu^\mp$

Riles, Keith ; Dorfan, J. ; Abrams, G.S. ; et al.
Phys.Rev.D 35 (1987) 2914, 1987.
Inspire Record 236093 DOI 10.17182/hepdata.23380

We have searched for the lepton-flavor-violating decay D0→e±μ∓ in 204 pb−1 of e+e− annihilation data at Ec.m.=29 GeV from the Mark II detector. No candidates were found; we estimate an upper limit on the cross section times branching ratio of σ(e+e−→D0,D¯0; inclusive)B(D0→e±μ∓)<0.35 pb at the 90% confidence level. Simple assumptions yield the rough limit B(D0→e±μ∓)<2.1×10−3. AE.

1 data table

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A Study of the Emc Effect Using Neutrino and Anti-neutrino Interactions in Neon and Deuterium

The WA25 & WA59 collaborations Guy, J. ; Saitta, B. ; Apeldoorn, G.Van ; et al.
Z.Phys.C 36 (1987) 337-348, 1987.
Inspire Record 236239 DOI 10.17182/hepdata.15733

Nearly 40000 neutrino and antineutrino interactions in BEBC are compared to measure the differences between neon and deuterium in the quark and antiquark distributions and in the nucleon structure functions. The ratio of Ne to D cross sections indicates some decrease betweenx∼0.2 andx∼0.6. They distributions show there is no significant increase in the neon sea, but prefer a small decrease. Taken altogether, thex andy distributions and the measured total cross-sections indicate some change in the shape of the valence distributions. No significant dependence onA is observed for either the shape of the sea or the ratio of longitudinal to transverse cross-sections.

12 data tables

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