Date

Anti-proton - Proton Elastic Cross-sections in the Momentum Range Between 180-{MeV}/$c$ and 600-{MeV}/$c$

Bruckner, W. ; Dobbeling, H. ; Guttner, F. ; et al.
Phys.Lett.B 166 (1986) 113-118, 1986.
Inspire Record 217928 DOI 10.17182/hepdata.30308

Differential cross sections for p̄p elastic scattering have been measured in the full angular range for the p̄ momenta between 180 and 600 MeV/ c . It is found that s- and p-wave scattering is dominant below 300 MeV/ c . The s-wave component in the total cross section is 40–60% below 300 MeV/ c , in contrast to the NN scattering where it is about 90%. The s-, p- and d-wave scattering amplitudes are derived.

3 data tables

No description provided.

No description provided.

No description provided.


Direct Photon Pair Production From Pions and Protons at 200-{GeV}/$c$

The NA3 collaboration Badier, J. ; Bardadin-Otwinowska, M. ; Bemporad, C. ; et al.
Phys.Lett.B 164 (1985) 184-188, 1985.
Inspire Record 217947 DOI 10.17182/hepdata.30329

We present results from a direct photon pair search performed with the NA3 spectrometer, using incident positive and negative beams at 200 GeV/ c interacting with a carbon target. The experiment is sensitive to photons with p T >1.8 GeV / c and −0.4⩽y ∗ ⩽1.0 , one in each arm of the apparatus. A 3 standard deviation signal is seen in τ − and p interactions. The cross section is higher than the second order QCD calculations, but systematic errors are large.

1 data table

No description provided.


HADRON MULTIPLICITY VARIATION WITH Q**2 AND SCALE BREAKING OF THE HADRON DISTRIBUTIONS IN DEEP INELASTIC MUON - PROTON SCATTERING

The European Muon collaboration Arneodo, M. ; Arvidson, A. ; Aubert, J.J. ; et al.
Phys.Lett.B 165 (1985) 222-228, 1985.
Inspire Record 217810 DOI 10.17182/hepdata.30328

Measurements are presented of the variation with Q 2 (scaling violation) of the hadron multiplicity in deep inelastic muon-proton scattering. An increase in the average multiplicity of both the charged hadrons and K 0 mesons is observed with increasing Q 2 or x Bj for fixed centre-of-mass energy W . The study of the shape of the effective fragmentation function D h ( z , W , Q 2 ) shows that the increase of the particle yield with Q 2 takes place for low z particles. The variation of the hadron distributions with Q 2 is also studied in the current fragmentation region where a decrease in multiplicity is observed. Such effects are expected from QCD.

2 data tables

No description provided.

No description provided.


Charged Meson Pair Production in $\gamma \gamma$ Interactions

Boyer, J. ; Burke, D.L. ; Butler, F. ; et al.
Phys.Rev.Lett. 56 (1986) 207, 1986.
Inspire Record 220003 DOI 10.17182/hepdata.20236

The cross section for the production of π+π− or K+K− pairs in γγ interactions is measured for mππ between 1.7 and 3.5 GeV/c2 and for two intervals of γγ center-of-mass scattering angle. Results are compared with predictions of a QCD model.

2 data tables

Data read off graph.

Data read off graph.


Observation of a Narrow K anti-K State in J/psi Radiative Decays

The MARK-III collaboration Baltrusaitis, R.M. ; Becker, J. ; Blaylock, G. ; et al.
Phys.Rev.Lett. 56 (1986) 107, 1986.
Inspire Record 217856 DOI 10.17182/hepdata.20254

Evidence is presented for a narrow state, called ξ, in the decay modes J/ψ→γξ, ξ→K+K−, and ξ→KS0KS0. In the K+K− mode, the ξ has a mass of 2.230±0.006±0.014 GeV/c2, a width of Γ=0.026−0.016+0.020± 0.017 GeV/c2, a product branching ratio of (4.2−1.4+1.7±0.8)×10 −5, and a statistical significance of ∼4.5 standard deviations. In the KS0KS0 mode, it has a mass of 2.232±0.007±0.007 GeV/c2, a width of Γ=0.018−0.015+0.023± 0.010 GeV/c2, a product branching ratio of (3.1−1.3+1.6±0.7)×10 −5, and a statistical significance of ∼3.6 standard deviations. Limits on ξ decay to other final states are presented.

1 data table

No description provided.


Upper Limits of the Proton Magnetic Form-factor in the Timelike Region From $\bar{p} p \to e^+ e^-$ at the {CERN} {ISR}

The Annecy(LAPP)-CERN-Genoa-Lyon-Oslo-Rome-Strasbourg-Turin collaboration Baglin, C. ; Baird, S. ; Bassompierre, G. ; et al.
Phys.Lett.B 163 (1985) 400-403, 1985.
Inspire Record 218159 DOI 10.17182/hepdata.49639

From the measurement of e + e - pairs from the reaction p̄p→e + e - at the CERN-ISR, using an antiproton beam and a hydrogen jet target, we derived upper limits for the proton magnetic form factor in the time-like region at Q 2 ⋍8.9( GeV c ) 2 and Q 2 ⋍12.5( GeV c ) 2 .

1 data table

No description provided.


Evidence for Pomeron Single Quark Interactions in Proton Diffraction at the {ISR}

The R608 collaboration Smith, A.M. ; Meritet, L. ; Reyrolle, M. ; et al.
Phys.Lett.B 163 (1985) 267-272, 1985.
Inspire Record 216801 DOI 10.17182/hepdata.30332

Measurements are presented of two exclusive diffractive reactions, pp → (Λ 0 φ 0 K + ) p and pp → (Λ 0 Λ 0 p)p , at √ s = 63 GeV . Pronounced correlations with the beam direction are observed (in the rest frame of the forward-going bracketed system) for those outgoing particles which contain the beam valence quarks. In each case there is a forward-Λ 0 in correlation with a backward K + or p, respectively. No such behavior is seen for the particles which do not contain beam valence quarks (φ 0 and Λ 0 , respectively) . Interpreted as examples of pomeron-proton scattering, these results constitute evidence that, for these final states, the pomeron interacts with a single valence quark and apparently back-scatters it. The subsequent hadronization leads to a longitudinal event structure.

3 data tables

Cross sections for forward LAMBDA signal counting both arms of the p p interaction.

Cross sections for forward LAMBDA signal counting both arms of the p p interaction.

No description provided.


Inclusive Charged Particle Distribution in Nearly Threefold Symmetric Three Jet Events at $e$({CM}) = 29-{GeV}

Petersen, A. ; Abrams, G.S. ; Amidei, D. ; et al.
Phys.Rev.Lett. 55 (1985) 1954, 1985.
Inspire Record 216850 DOI 10.17182/hepdata.20285

We report a measurement of the inclusive charged-particle distribution for gluon jets derived from nearly threefold-symmetric three-jet events taken at center-of-mass energy of 29 GeV in e+e− annihilation. The charged-particle spectrum for these jets is observed to fall off more rapidly than those of quark jets of the same energy.

1 data table

Errors include both statistics and the uncertainty in correction factors. X is defined at the energy of the individual particle divided by the total energy of the jet to which it is assigned.


Inclusive $\phi$ Production in $K^- p$ Interactions at 110-{GeV}/$c$ and Search for Structure in $\phi \pi^-$

The Bombay-CERN-Cracow-Innsbruck-London-Vienna-Warsaw collaboration Banerjee, S. ; Ganguli, S.N. ; Gurtu, A. ; et al.
Z.Phys.C 31 (1986) 401, 1986.
Inspire Record 217420 DOI 10.17182/hepdata.15873

Results on inclusive ϕ production inK−p interactions at 110 GeV/c are presented. The production cross section is found to be larger than in πp andpp interactions at similar energies, suggesting OZI allowed\(s\bar s\) fusion to be the dominant mechanism in ϕ production. Thex distributions of ϕ and\(\bar K^{*0} \) are found to be similar to each other over the entirex range suggesting an overall strangeness suppression factor of 0.20±0.04 in the sea to be the dominant source of the difference in the cross section for ϕ and\(\bar K^{*0} \). There is no evidence of a narrowφπ− state around 2.1 GeV/c2 as suggested byK+ experiments, but there is some excess of events in the region 1.94−1.98 GeV/c2 consistent with theF-meson mass as observed ine+e− experiments.

2 data tables

Errors contain both statistics and systematics.

F(XL) is invariant cross section.


Study of the Reaction $\gamma \gamma \to 2 \pi^+ 2 \pi^- \pi^0$ and Upper Limits on the Production of $\gamma \gamma \to \omega \omega$ and $\gamma \gamma \to \rho^0 \omega$

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Lackas, W. ; et al.
Z.Phys.C 29 (1985) 183, 1985.
Inspire Record 220911 DOI 10.17182/hepdata.15911

A search for the reactionsγγ→ωω andγγ→ρ0ω has been carried out at an averagee+e− CM energy of 34.6 GeV with an integrated luminosity of 45 pb−1. Upper limits are set for these two channels over the γγ CM Energy range of 1.6 to 2.5 GeV. The cross section is determined for the exclusive channelγγ→π+2π−π0.

3 data tables

Data read from graph.

Data read from graph.

Data read from graph.