HEPData Search

In order to determine the ηNN coupling constant we have measured the two reactions K − p→ Λη and K − p→ Λπ 0 with a magnetic wire chamber spectrometer which contained a gamma counter for the γγ decays of π 0 and η. The Λ polarization and the differential cross sections are given. The latter have quite different u dependences. Their ratio is interpreted, in terms of a nucleon-Regge exchange model, as the effect of a small ηNN coupling constant for which we obtain G η NN 2 = G π NN 2 · (0.26 ± 0.10) as allowed by SU(3). The large value given by Heisenberg's non-linear field theory, G η NN 2 = G π NN 2 · 0.9, is excluded by this measurement if the characteristic u dependence of the Λπ 0 channel is attributed to N α Regge exchange.

4 data tables

Table 1

Axis error includes +- 10/10 contribution.

Table 2

No description provided.

Table 3

Axis error includes +- 10/10 contribution.

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Forward A2+ in Two-dimensions Production in $\pi^+ p \to K^+ \bar{K}(s$)0 $p$ at 12.7-{GeV}/$c$

Hyams, B. ; Jones, C. ; Weilhammer, P. ; et al.

Nucl.Phys.B 146 (1978) 303-326, 1978.

Inspire Record 132236 DOI 10.17182/hepdata.34849

Approximately 350 A 2 + events have been observed in the reaction π + p → K + K S 0 p ( K S 0 → π + π − ) at an incident π + laboratory momentum of 12.7 GeV/ c . The events are distributed over a range of four-momentum transfer squared 0.01 ⩽ − t ⩽ 0.60 (GeV/ c ) 2 and K + K S 0 mass 1.11 ⩽ m K + K S 0 ⩽ 1.51 GeV . A Breit-Wigner fit to the mass spectrum yields a mass for the A 2 + , m A 2 + = 1.324 ± 0.005 GeV, and a width Γ 0 = 0.110 ± 0.018 GeV. We find a cross section σ ( π + p → A 2 + p) = 1.71 ± 0.30 μb referring to the above-mentioned mass and t range and A 2 + → K + K S O with K S 0 → π + π − . The spin-space density matrix in the Gottfried-Jackson frame is practically saturated by ϱ 11 ⋍ ϱ 1−1 = 1 2 suggesting natural parity exchanges only. There is a forward dip in the angular distribution consistent with dominance of s -channel net helicity flip amplitudes and ϱ and f Regge exchanges suffice to describe adequately our differential cross sections.

5 data tables

Table 1

SUBTRACTED BACKGROUND IS PHASE SPACE. FITTED D(SIG)/DT SLOPE IS 9.5 +- 0.9 GEV**-2.

Table 2

SUBTRACTED BACKGROUND IS AN S-WAVE WITH SLOPE OF 8 GEV**-2. FITTED D(SIG)/DT SLOPE IS 6.9 +- 0.6 GEV**-2.

Table 3

FROM D(SIG)/DT. ERROR INCLUDES 15 PCT SCALE ERROR ADDED QUADRATICALLY.

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A2- Production in the Reaction $\pi^- p \to K^- K^0_S p$ at 9.8-{GeV} and 18.8-{GeV}

The CERN-Munich collaboration Chabaud, V. ; Hyams, B. ; Jones, C. ; et al.

Nucl.Phys.B 145 (1978) 349-366, 1978.

Inspire Record 131631 DOI 10.17182/hepdata.34875

Results of two spark chamber experiments on A 2 − production in the reaction π − p → K − K S 0 (→ π + π − )p at 9.8 and 18.8 GeV are presented. Decay angular distributions and differential cross sections are given, and the energy dependence of the cross section σ [ π − p → A 2 − (→ K − K 0 )p] is compared with results from π − p → A 2 − (→ 3 π )p.

4 data tables

Table 1

FITS WITH CONSTANT BACKGROUNDS. A TWO-PARAMETER LINEAR BACKGROUND GIVES MUCH LARGER ERRORS.

Table 2

INTEGRATED OVER M(K AK) = 1.20 TO 1.42 GEV.

Table 3

No description provided.

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Forward $K^*$+ (892) Production in $K^+ p \to \pi^+ K^0_S p$ at 12.7-{GeV}/$c$

Sacharidis, E.J. ; Blum, W. ; Dietl, H. ; et al.

Nucl.Phys.B 179 (1981) 9-32, 1981.

Inspire Record 154321 DOI 10.17182/hepdata.34347

We have measured 618 K + p → π + K S 0 p events at 12.7 GeV/ c incident lab momentum, mass range 790 ⩽ m π + K s 0 ⩽ 990 MeV and t range 0.01 ⩽ − t ⩽ 0.60 (GeV/ c ) 2 . The π + K S 0 mass spectrum is dominated by the K ∗+ (892) resonance and a Breit-Wigner fit yields a mass m = 893.5 ± 1.1 MeV and a width Γ = 33.2 ± 4.1 MeV which is much narrower than measured hitherto. The t distribution of K ∗+ (892) events shows a dip in the forward direction and an exponential fall off thereafter, consistent with dominance of helicity flip amplitudes. The spin density matrix is almost saturated by ρ 11 and ρ 1−1 which are very close to their maximum allowed value of 1 2 throughout the measured t range except in the very forward direction where ρ 00 and Re ρ 10 deviate from zero. Natural parity exchanges, therefore, dominate with unnatural parity exchanges being restricted to a small region in the forward direction. A Regge pole analysis of the differential cross sections of the present measurement in conjunction with previously measured total cross sections supports the f-coupled-pomeron hypothesis.

3 data tables

Table 1

SUBTRACTED BACKGROUND IS PHASE SPACE.

Table 2

SUBTRACTED BACKGROUND IS AN INCOHERENT S-WAVE WITH EXPONENTIAL T-DEPENDENCE WITH SLOPE OF 6 GEV**-2.

Table 3

Axis error includes +- 15/15 contribution.

Measurement of the pseudoscalar decay constant, f(D).

The BES collaboration Bai, J.Z. ; Bardon, O. ; Blum, Ira K. ; et al.

SLAC-PUB-7147, 1996.

Inspire Record 421008 DOI 10.17182/hepdata.18760

None

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Search for psi(2S) production in e+ e- annihilations at 4.03-GeV

The BES collaboration Bai, J.Z. ; Bian, J.G. ; Blum, I. ; et al.

Phys.Rev.D 57 (1998) 3854-3859, 1998.

Inspire Record 468969 DOI 10.17182/hepdata.22270

A search is performed for the production of the ψ(2S) in e+e− annihilation at a center-of-mass energy of 4.03 GeV using the BES detector operated at the Beijing Electron Positron Collider (BEPC). The kinematic features of the reconstructed ψ(2S) signal are consistent with its being produced only in association with an energetic photon resulting from initial state radiation (ISR). Limits are placed on ψ(2S) production from the decay of unknown charmonia or metastable hybrids that might be produced in e+e− annihilations at 4.03 GeV. Under the assumption that the observed cross section for ψ(2S) production is due entirely to ISR, the partial width Γee of the ψ(2S) is measured to be 2.07±0.32keV.

1 data table

Table 1

PSI(UNSPEC) is considered as a new 3D2 charmonium state. CHI/C(UNSPEC) is considered as any unknown charmonium state. EXOTIC is considered as a metastable hybrid.

Total cross-section for n-p and n-d scattering at 10 GeV/c neutron momentum

Engler, J. ; Horn, K. ; König, J. ; et al.

Phys.Lett.B 27 (1968) 599-601, 1968.

Inspire Record 1389110 DOI 10.17182/hepdata.752

The total neutron cross-sections were measured with high precision for hydrogen and deuterium. At an average neutron momentum of 10 GeV/c we obtained σ T (np)=39.5±0.5 mb and σ T (nd)=73.3±1.1 mb. These values are in excellent agreement with p-p and p-d total cross sections. No energy dependence was found for n-p cross section between 4 and 10 GeV/c.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Elastic scattering and polarisation in 3.0 and 3.6 GeV/c antiproton-proton collisions

Escoubès, B. ; Fedrighini, A. ; Goldschmidt-Clermont, Y. ; et al.

Phys.Lett. 5 (1963) 132-136, 1963.

Inspire Record 1389108 DOI 10.17182/hepdata.751

None

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Multihadron production in e+ e- collisions at high energy

Grilli, M. ; Iarocci, E. ; Spillantini, P. ; et al.

Nuovo Cim.A 13 (1973) 593-644, 1973.

Inspire Record 87243 DOI 10.17182/hepdata.1179

Multihadron production by electron-positron colliding beams has been investigated for total centre-of-mass energies ranging from 1.2 to 2.4 GeV. The total cross-section, σtot ≡ σ(e+e−→π+π−+ + anything), is of the order of σμμ ≡ σ(e+e−→μ+μ−), with a threshold near 1 GeV. Partial cross-sections for the various channels are also derived. The cross-section of the specific channel e+e−→π+π−π+π− exhibits an energy dependence which is suggestive of a heavier vector meson, ρ' (mρ,≈ 1.6 GeV,Гρ, ≈ 350 Mev), having the same quantum numbers as the ρ-meson. An upper limit is given for the coupling constantfρ′ (fρ′/4π<18, wherefρ′=mρ′2e/gγρ′). Final states withG+ parity are found to be much more abundant than those withG− parity. The average multiplicity (charged plus neutral final-state pions) is found to be betweet 4 and 5 over all the energy range explored.

3 data tables

Table 1

No description provided.

Table 2

VALUES OF R CALCULATED FROM TOTAL CROSS SECTION.

Table 3

No description provided.

Date

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Reactions

Observables

CM Energies (GeV) Reset

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Measurement of the Reactions $\bar{P} P \to \bar{\Lambda} \Lambda$, $\bar{p} p \to \bar{\Lambda} \Sigma^0$ and $\bar{P} P \to \bar{\Lambda}$ (Missing Mass) at 6-{GeV}

Measurement of the Baryon Exchange Reactions $K^- p \to \Lambda \eta$, $K^- p \to \Lambda \pi^0$ at 6-{GeV}/$c$ and the Value of the $\eta N N$ Coupling Constant

Forward A2+ in Two-dimensions Production in $\pi^+ p \to K^+ \bar{K}(s$)0 $p$ at 12.7-{GeV}/$c$

A2- Production in the Reaction $\pi^- p \to K^- K^0_S p$ at 9.8-{GeV} and 18.8-{GeV}

Forward $K^*$+ (892) Production in $K^+ p \to \pi^+ K^0_S p$ at 12.7-{GeV}/$c$

Measurement of the pseudoscalar decay constant, f(D).

Search for psi(2S) production in e+ e- annihilations at 4.03-GeV

Total cross-section for n-p and n-d scattering at 10 GeV/c neutron momentum

Elastic scattering and polarisation in 3.0 and 3.6 GeV/c antiproton-proton collisions

Multihadron production in e+ e- collisions at high energy