Date

The Reactions K+ p --> Lambda x++ and K+ p --> anti-Lambda x++ at Incident Momenta of 8.2-GeV/c and 16.0-GeV/c

Chliapnikov, P.V. ; Ciapetti, G. ; Dunwoodie, W. ; et al.
Nucl.Phys.B 112 (1976) 1-51, 1976.
Inspire Record 109100 DOI 10.17182/hepdata.35646

Inclusive production of Λ and Λ in K + p interactions is studied at incident momenta of 8.2 and 16.0 GeV/ c . Cross sections and single-particle distributions are presented, the correlation between longitudinal and transverse momentum is investigated, and the dependence of average charge multiplicity on missing mass measured. For Λ production, early scaling is observed in the target fragmentation region when the data are presented in terms of ( M 2 - M th 2 )/ s and t , where M th is the threshold value of the missing mass M . Furthermore, a triple-Regge analysis in these variable yields an effective exchange trajectory which passes through the K, Q and L mesons. There is evidence for beam fragmentation in Λ and Λ production, but the contributions seem not to be dominant in the fragmentation region. Nevertheless, the parameter values in a triple-Regge description are estimated, and together with those for target fragmentation in Λ production, provide a complete description of the fragmentation contributions to the two reactions. Integration of the resultant distribution functions over the complete Chew-Low plot yields fragmentation cross sections increasing approximately as log s ; in addition the observed features of the x , p L and p T 2 projections and of the p L - p T correlation are well-described in the fragmentation regions. Central production contributions are isolated by subtracting the calculated fragmentation distributions

20 data tables

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Inclusive $\pi^0$ Production at Large Transverse Momentum from $\pi^{\pm} p$ and pp Interactions at 100 and 200 GeV/c

Donaldson, G. ; Gordon, H. ; Lai, K.-W. ; et al.
Phys.Rev.Lett. 36 (1976) 1110, 1976.
Inspire Record 108958 DOI 10.17182/hepdata.21118

We have measured large-transverse-momentum (p⊥) inclusive π0 production at c.m. angles centered near 90° for π±p and pp interactions at 100 and 200 GeV/c. This is the first such measurement using a pion beam. The ratio σ(pp→π0X)σ(πp→π0X) decreases with increasing p⊥ and is independent of energy when expressed as a function of x⊥=p⊥pmax. We compare the data with predictions of various models.

6 data tables

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Production of Sigma (1660) in K- p Interactions at 4.2-GeV/c

The Amsterdam-CERN-Nijmegen-Oxford collaboration Timmermans, Jan ; Engelen, J.J. ; Heinen, P.M. ; et al.
Nucl.Phys.B 112 (1976) 77-106, 1976.
Inspire Record 108671 DOI 10.17182/hepdata.35709

The reaction of K − p → Σ + (1660) π − was studied in a 65 event/μb sample of Σππ(π), Λππ(π) and p K 0 π − final states. The main production features observed are that the Σ (1660) decaying into Σππ is mostly Λ (1405) π and is produced only at small t ; the Σ (1660) decaying into Σπ shows both forward and backward production. This confirms earlier results suggesting the existence of two Σ (1660) resonances. An Adair analysis and a (model-dependent) moments analysis find a J = 3 2 preference for the Σ + (1660)→ Λ (1405) π + → Σ + π − π + ; a Dalitz-Miller analysis of the decay Σ + (1660) → Λ (1405) π + → Σ − π + π + determines J P to be 3 2 − . For the Σ + (1660) → Σ 0 π + a moments analysis suggests J = 3 2 . Branching ratios are determined, which (with the exceptation of the Λ (1405) π mode) are in reasonable agreement with results from formation experiments for the J P = 3 2 − Σ(1660) resonance. We compare our branching ratios with SU(3) and SU(6) predictions; the latter comparison suggests that, unless there is strong configuration mixing, Σ (1660) → Λ (1405) π , if 3 2 − , cannot be a member of the (70, 1 − ) multiplet.

4 data tables

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PRODUCTION ANGULAR DISTRIBUTIONS OF SIG(1670D13)+ DIFFER FOR THE TWO FINAL STATES <LAM(1405S01) PI+> AND <SIGMA PION> SUGGESTING THE EXISTENCE OF TWO SIG(1660) RESONANCES.

VALUES IN STRONG DISAGREEMENT WITH THE STODOLSKY-SAKURAI MODEL PREDICTIONS.

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Large t Elastic Proton Proton Scattering at s**(1/2) = 53-GeV

de Kerret, H. ; Nagy, E. ; Regler, M. ; et al.
Phys.Lett.B 62 (1976) 363-365, 1976.
Inspire Record 108743 DOI 10.17182/hepdata.27660

New experimental results are presented on proton-proton elastic scattering in the range of momentum transfer 0.8GeV 2 < − t < 9 GeV 2 at a centre-of-mass energy of √ s = 53 GeV. The data are obtained sing the Split-Field- Magnet Detector at the CERN Intersecting Storage Rings. The cross section has well-known minimum at − t = (1.34±0.02) GeV 2 but no further minimum or change of slope is observed between 2 and 6.5 GeV 2 .

1 data table

Axis error includes +- 0.0/0.0 contribution (?////THE QUOTED ERRORS ARE THE QUADRATIC SUM OF STATISTICAL AND ESTIMATED SYSTEMATIC ERRORS. THE SYSTEMATIC ERRORS ARE NOT INDEPENDENT FROM BIN TO BIN).


A Measurement of the Cross-Section of the Reaction p p --> n Delta++ (1232) at ISR Energies

Kwak, N. ; Nagy, E. ; Regler, M. ; et al.
Phys.Lett.B 62 (1976) 359-362, 1976.
Inspire Record 108757 DOI 10.17182/hepdata.27678

A measurement of the cross section of the charge-exchange reaction pp→ Δ ++ (1232)n at √ s = 23, 31 and 45 GeV at the CERN-ISR is reported. The energy dependence continues to follow a power law p lab − n with n = 1.94 ± 0.03 indicating dominance of one-pion exchange at the lowest ISR energy; there is some evidence for deviation from this at the higher ISR energies.

3 data tables

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The Real Part of anti-p p Forward Elastic Scattering Amplitude at 0.7-GeV/c

Kaseno, H. ; Hamatsu, R. ; Kawano, K. ; et al.
Phys.Lett.B 61 (1976) 203-206, 1976.
Inspire Record 3400 DOI 10.17182/hepdata.27693

The differential cross sections of p p elastic scattering at 0.7 GeV/ c were obtained in the range 0.0018<| t |⩽0.0320 GeV 2 . From the interference between the Coulomb and the nuclear amplitude, the ratio of real to imaginary part of the forward nuclear amplitude was found to be +0.33±0.04.

3 data tables

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FIT FOR FORWARD NUCLEAR AMPLITUDE IN COULOMB INTERFERENCE REGION.


Measurement of the Polarization in Backward Angle pi- p Elastic Scattering at 2.93-GeV/c and 3.25-GeV/c

Auer, P. ; Bridges, D. ; Droege, T. ; et al.
Nucl.Phys.B 113 (1976) 279-284, 1976.
Inspire Record 3320 DOI 10.17182/hepdata.35605

Polarization in π − p elastic scattering, with emphasis over the backward region, has been measured at 2.93 and 3.25 GeV/ c . We observe large changes in polarization compared with existing data above and below these energies. Our data may be useful in determining the properties of resonances and in understanding baryon exchanges.

1 data table

THESE DATA, TOGETHER WITH THE FORWARD SCATTERING POLARIZATION MEASUREMENTS, ARE TABULATED IN THE RECORD OF P. AUER ET AL., PRL 37, 83 (1976).


Rho+- Photoproduction at 9.6-GeV

Abramson, J. ; Andrews, D.E. ; Busnello, R. ; et al.
Phys.Rev.Lett. 36 (1976) 1432, 1976.
Inspire Record 108497 DOI 10.17182/hepdata.21105

ρ± photoproduction from hydrogen and deuterium at 9.6 GeV is studied. The reactions γp→ρ+n and γp→ρ−Δ++(1236) have cross sections much larger than expected from pion exchange alone. t distributions do not show the sharp forward peak characteristic of one-pion exchange contributions. Density matrices indicate an isotropic decay distribution. The ratio of ρ+ to ρ− production on deuterium differs from unity and by the amount expected from interference between ρ and A2 exchanges. We conclude that π exchange is unimportant for ρ± photoproduction, and infer that ρ exchange dominates.

7 data tables

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DENSITY MATRICES IN HELICITY FRAME - UNPUBLISHED.

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Production of $\psi$ (3100) and $\psi^{\prime}$ (3700) in p-Be Collisions at 400 GeV

Snyder, H.D. ; Hom, D.C. ; Lederman, L.M. ; et al.
Phys.Rev.Lett. 36 (1976) 1415, 1976.
Inspire Record 108462 DOI 10.17182/hepdata.21117

We report preliminary results on the production of electron-positron pairs in the mass range 2.5 to 4 GeV in 400-GeV p-Be interactions. Production cross sections of the ψ(3100) near x=0 as a function of pt, x, and the decay angle are presented and implications of these new data for single direct leptons are discussed. A ψ′(3700) signal is observed at a level corresponding to σ(ψ′)σ(ψ)=(10±3)%.

1 data table

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A Comparison of the Shapes of pi+ p and p p Diffraction Peaks from 50-GeV/c to 175-GeV/c

The Fermilab Single Arm Spectrometer Group collaboration Ayres, D.S. ; Diebold, Robert E. ; Maclay, G.J. ; et al.
Phys.Rev.Lett. 37 (1976) 548, 1976.
Inspire Record 108238 DOI 10.17182/hepdata.21073

The ratio of π+p to pp elastic scattering is found to be smoothly varying over the range −t=0.03 to 0.4 GeV2. It is well fitted by a single exponential, indicating the forward behavior must be quite similar for the two reactions.

1 data table

ACTUALLY THE DATA ARE THE EXPONENTIAL SLOPE OF THE RATIO OF D(SIG)/DT FOR THE TWO REACTIONS.