HEPData Search

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Strangeness Exchange in the Photoproduction of $K^+ \Lambda$ (1520) Between 2.8-{GeV} and 4.8-{GeV}

Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.

Z.Phys.C 7 (1980) 17, 1980.

Inspire Record 153887 DOI 10.17182/hepdata.14096

A tagged photon beam (2.8<Eγ<4.8 GeV) and multiparticle spectrometer have been used to study the photoproduction in hydrogen ofK+Λ(1520). Precise values for the mass and width of the Λ(1520) are given. The total cross-section is found to fall with increasing photon energy like (6.5±0.7)Eγ−(2.1±0.2) μb. The differential cross sectiondσ/dt indicates peripheral forward production and exhibits no evidence for shrinkage when compared with higher energy data. The Λ(1520) spin density matrix shows thatK exchange alone cannot account for the production mechanism. The reaction is found to resemble the process γp→K+ Λ(1115) in all measurable respects.

3 data tables

Table 1

FITTED CROSS SECTION ENERGY DEPENDENCE IS SIG = (6.7 +- 0.7 MUB*GEV**2) * P**(-2.1 +- 0.2), INCLUDING HIGHER ENERGY DATA.

Table 2

EXPONENTIAL SLOPE IS 6.1 +- 2.0 GEV**-2 FOR -T = 0.2 TO 0.7 GEV**2.

Table 3

No description provided.

Comparison of Strange Anti-baryon and Strange Meson Production in $K^+ p$ Interactions at 32-{GeV}/$c$

Chliapnikov, P.V. ; Gerdyukov, L.N. ; Khromova, G.N. ; et al.

Z.Phys.C 12 (1982) 99, 1982.

Inspire Record 167341 DOI 10.17182/hepdata.10880

New experimental results are presented on inclusive production properties of$\bar \Sigma ^{ *+ } $(1385) and$\bar \Sigma ^{ *+ } $(1385) inK+p interactions at 32 GeV/c. The analysis is based on significantly larger statistics than previously available. A comparison is also made of invariantx-distributions ofK0/$\bar K^0 $,$\bar \Lambda $ and$\bar \Xi ^ +$ and of$\bar \Sigma ^{ *\pm } $(1385) andK*+(892). These spectra exhibit regularities expected from the quark-recombination picture when it is assumed that the strange mesons and antibaryons are produced off the strange$\bar s$-valence-quark in the incidentK+ meson. Transverse momentum distributions are also presented forK*+(892) and$\bar \Sigma ^{ *\pm } $(1385) and found to be very similar. The results on strange antibaryon average multiplicities disagree strongly with a recent version of the additive quark model.

32 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Photoproduction of $\pi \Delta(1232)$ From Hydrogen in the Energy Range 2.4-{GeV} to 4.8-{GeV}

The LAMP2 Group collaboration Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.

Z.Phys.C 6 (1980) 93, 1980.

Inspire Record 153944 DOI 10.17182/hepdata.14328

We present differential cross sections andΔ++ spin density matrix elements for the photoproduction processγp→π−Δ++ and differential cross sections for the processγp→π+Δ0. The incident photon energy dependence is studied and a comparison is made with previous experiments and with the predictions of a theoretical model.

5 data tables

Table 1

DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.

Table 2

DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.

Table 3

DIFFERENTIAL CROSS SECTION FOR DIFFERENT ENERGY RANGES.

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Inclusive $\Lambda$ and $\bar{\Lambda}$ Production in $K^+ p$ Interactions at 70-{GeV}/$c$

The Brussels-CERN-Genoa-Mons-Nijmegen-Serpukhov collaboration Barth, M. ; De Clercq, C. ; De Wolf, E.A. ; et al.

Z.Phys.C 10 (1981) 205, 1981.

Inspire Record 166163 DOI 10.17182/hepdata.2217

Inclusive and semi-inclusive production of Λ and$\bar \Lambda$ inK+p interactions is studied at an incident momentum of 70 GeV/c. Cross sections and single particle distributions are presented and compared with data at lower energies. Scaling is observed between 32 and 70 GeV/c in the Feynmanx variable in the target and the beam fragmentation regions for Λ and$\bar \Lambda$ inclusive production respectively. An increase of Λ ($\bar \Lambda$) production is observed in the beam (target) fragmentation regions, whereas the data at 70 and 32 GeV/c are reasonably close in the central region. The dependence of the Λ($\bar \Lambda$) polarization as a function ofx is measured and found to be in general agreement with the results at 32 GeV/c. The (Λ$\bar \Lambda$) pair production cross section increases significantly from 32 to 70 GeV/c. The Λ and$\bar \Lambda$ production associated with an identified proton is also studied.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV

The LHCb collaboration Aaij, R. ; Adeva, B. ; Adinolfi, M. ; et al.

Eur.Phys.J.C 71 (2011) 1645, 2011.

Inspire Record 891233 DOI 10.17182/hepdata.57066

The production of $J/\psi$ mesons in proton-proton collisions at $\sqrt{s}$= 7 tev is studied with the LHCb detector at the LHC. The differential cross-section for prompt $J/\psi$ production is measured as a function of the $J/\psi$ transverse momentum p_{\rm T}\ and rapidity $y$ in the fiducial region $p_{\rm T}\in[0;14]$ GeV/c and $y\in[2.0;4.5]$. The differential cross-section and fraction of \j psi\ from $b$-hadron decays are also measured in the same p_{\rm T}\ and $y$ range s. The analysis is based on a data sample corresponding to an integrated luminos ity of 5.2 pb$^{-1}$. The measured cross-sections integrated over the fiducial region are $10.52\pm 0. 04\pm 1.40^{+1.64}_{-2.20}\mu b$ for $\mathrm{prompt}~J/\psi$ production and $1.14 \pm 0. 01\pm 0.16 \mu b$ for $J/\psi$ from $b$-hadron decays, where the first uncertainty is statistical and the second systematic. The $\mathrm{prompt}~J/\psi$ production cross-section is obtained assuming no $J/\psi$ polarisation and the third error indicates the acceptance uncertainty due to this assumption.

10 data tables

Table 1

Integrated cross section in the defined fiducial region for prompt J/PSIs and for those from b-hadron decay assuming no polarisation. The second systematic error in the prompt cross section is the uncertainty related to the assumption of no polarisation.

Table 2

The derived cross section for b-hadron production obtained by extrapolation to the full polar angle range using the LHCB MC based on Pythia6.4 and EvtGen and a branching ratio to J/PSI of 1.16+-0.1 PCT.

Table 3

Mean PT and RMS for prompt J/PSI production (assuming unpolarised).

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INCLUSIVE pi0 PHOTOPRODUCTION AND THE QUARK - PARTON MODEL

The LAMP2 Group collaboration Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.

Phys.Lett.B 77 (1978) 233-239, 1978.

Inspire Record 129937 DOI 10.17182/hepdata.27429

We present measurements on the inclusive structure function for π 0 photoproduction for the incident photon energy range of 2.8–4.8 GeV. Comparisons are made with electroproduction data and it is found that the scaling behaviour already observed for finite q 2 continues to be valid at q 2 = 0.

1 data table

Table 1

No description provided.

Study of Inclusive Production of $\pi^\pm$ and Protons in $\bar{p} p$ Interactions at 32-{GeV}/$c$

The French-Soviet & CERN-Soviet collaborations Vlasov, E.V. ; Babintsev, V.V. ; Bumazhnov, V.A. ; et al.

Z.Phys.C 13 (1982) 95, 1982.

Inspire Record 176790 DOI 10.17182/hepdata.1191

Results are presented on the inclusive production of π± mesons and protons in$\bar p$p interactions at an incident antiproton momentum of 32 GeV/c in the MIRABELLE bubble chamber, based on a sample of 55,000 inelastic events. The spectra of π+(π−) andp($\bar p$) are separated in the whole kinematically admitted region of phase space by a statistical method. The semi-inclusive and inclusive cross sections and the main average characteristics of π andp production are calculated. The invariant differential cross sections are studied as functions of the Fevnman scaling variablex, the rapidity and the transverse momentum. Thex distribution of π± mesons in the proton fragmentation region does not show any significant contribution from quark exchange or annihilation processes. A possible contribution of hard quark scattering on mesons or baryons is observed for large transverse momenta.

38 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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The $\rho^\prime$ (1600) in the Reaction $\gamma p \to \pi^+ \pi^- \pi^0 \pi^0 p$ at Photon Energies of 20-{GeV} to 70-{GeV}

The Omega Photon collaboration Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.

Z.Phys.C 26 (1985) 499, 1985.

Inspire Record 202941 DOI 10.17182/hepdata.15774

The reactionγp→π+π−π0π0p (excludingωπ0 production) has been studied for photon energies in the range 20–70 GeV. A peak is seen in the 4π mass spectrum at ∼1.66 GeV with a width of ∼0.3 GeV which is identified with theρ′(1600). Maximum likelihood fits show that the peak is dominantly inρ±π∓π0 withB(ρ′→ρ0π0π0)/B(ρ′→ρ±π∓π0)<0.1. This indicates anI=1ρπ final-state interaction. However, no evidence is found for any resonant ρπ state such as anA1 orπ′.

2 data tables

Table 1

AFTER OMEGA EXCLUSION.

Table 2

ERROR IS DOMINANTLY SYSTEMATIC.