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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The Reaction pi- p ---> eta n at High-Energies

Dahl, O.I. ; Johnson, R.A. ; Kenney, R.W. ; et al.
Phys.Rev.Lett. 37 (1976) 80, 1976.
Inspire Record 108647 DOI 10.17182/hepdata.21028

Measurements on the reaction π−p→ηn have been carried out at Fermilab with beam energies from 20 to 200 GeV in the same experiment in which pion charge-exchange scattering was studied. The differential cross sections have a pronounced dip in the forward direction. The data can be described well by a simple Regge-pole model but the resulting A2 trajectory is not degenerate with the ρ trajectory extracted from the charge-exchange data.

3 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).


Pion Charge Exchange Scattering at High-Energies

Barnes, A.V. ; Mellema, D.J. ; Tollestrup, A.V. ; et al.
Phys.Rev.Lett. 37 (1976) 76, 1976.
Inspire Record 108646 DOI 10.17182/hepdata.21046

We report on a study of pion charge-exchange scattering carried out at Fermilab in the energy range 20 to 200 GeV. The results can be described remarkably well by a simple Regge-pole model. The charge-exchange cross sections in the forward direction lead to a prediction for the difference in total cross sections of π−p and π+p which is in satisfactory agreement with direct measurements of this difference in another experiment at Fermilab.

3 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).


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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Experimental Results on Diffractive One Pion Production at the CERN ISR

de Kerret, H. ; Nagy, E. ; Regler, M. ; et al.
Phys.Lett.B 63 (1976) 477-482, 1976.
Inspire Record 109254 DOI 10.17182/hepdata.27619

New experimental results are reported on diffractive dissociation of protons into (nπ + ) in proton-proton collisions at a centre-of-mass energy of s = 45 GeV . The data were obtained using the Split-Field-Magnet detector at the CERN Intersecting Storage Rings. We have searched for resonance contributions and found peaks at mass values of 1.5 GeV, 1.65 GeV, and 2.1 GeV. A dip in d σ d t is observed at low t and low mass; it is most pronounced for events with neutrons emitted at 90° in the Gottfried-Jackson frame. The correlation between mass and slope depends strongly on θ J . The cross section of the channel pp → pnπ + is 400 ± 110 μb at s = 45 GeV , giving an energy dependence of s −0.30±0.07 for isospin exchange zero in this channel.

3 data tables

SCALE UNCERTAINTY 20 PCT IS INCLUDED IN ERROR.

SIG(P P --> P N PI+) IS NEARLY EQUAL TO SIG(P P --> P (N PI+)) WHICH WAS ACTUALLY MEASURED, SINCE THE CROSS SECTION OF THE REACTION P P --> N (P PI+) IS LESS THAN .1 MUB AS MEASURED BY N. KWAK ET AL., PL 62B, 359, 1976.

EXTRAPOLATING TO T=0 AND ALLOWING FOR OTHER DECAY MODES YIELDS RESULT.


Large Transverse Momentum Photons from High-Energy Proton Proton Collisions

Darriulat, P. ; Dittmann, P. ; Eggert, K. ; et al.
Nucl.Phys.B 110 (1976) 365, 1976.
Inspire Record 109343 DOI 10.17182/hepdata.35743

We have performed a simultaneous measurement of the large transverse momentum (1.6 to 3.8 GeV/ c ) yields of single photons and of photon pairs at 90° production angle in pp collisions at ISR energies. Production cross sections for each of these two processes are compared.

2 data tables

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Elastic Scattering Crossovers from 50-GeV to 175-GeV

The Fermilab Single Arm Spectrometer Group collaboration Anderson, R.L. ; Anelli, E.F. ; Ayres, D.S. ; et al.
Phys.Rev.Lett. 37 (1976) 1025, 1976.
Inspire Record 108810 DOI 10.17182/hepdata.21092

A comparison of K±p and p±p elastic scattering is made for incident energy 50 to 175 GeV. Average values of 0.19±0.04 and 0.11±0.02 GeV2 were found for the invariant-momentum-transfer values of the Kp and pp crossover points, respectively.

1 data table

KP AND PP CROSSOVER POINTS AT -T = 0.19 +- 0.04 AND 0.11 +- 0.02 GEV**2 (AVERAGE VALUES) RESPECTIVELY.


High Statistics Investigation of K0 K- Decay of a2- Produced by 23-GeV/c pi- on Hydrogen

Margulies, M. ; Kramer, M.A. ; Foley, K.J. ; et al.
Phys.Rev.D 14 (1976) 667, 1976.
Inspire Record 3806 DOI 10.17182/hepdata.24780

We present the results of an experiment to study the reaction π−p→A2−p, A2−→KS0K− at 22.4 and 23.9 GeV/c. We have 3346 KS0K− events in the effective mass region 1.1 to 1.5 GeV, and covering the |t′| interval 0.0 to 1.0 (GeV/c)2. Because of the low background in this channel, we are able to study various |t′| regions, including the region 0.2 to 0.29 (GeV/c)2 in which the original split A2 peak was observed. We find no substructure in any region. We have also derived differential and total cross sections. The differential cross sections are well fitted by the form dσdt′=At′ebt′ with b≈7.0 (GeV/c)−2. The total cross section is in good agreement with the value derived from other experiments that measure the A2−→ρ0π− decay mode.

3 data tables

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New Data on the Reaction K- n --> (Sigma pi)- and a Partial Wave Analysis of anti-K n --> Sigma pi in the Energy Range 1520-MeV-1745-MeV

Hepp, V. ; Braun, O. ; Grimm, H.J. ; et al.
Phys.Lett.B 65 (1976) 487-491, 1976.
Inspire Record 109742 DOI 10.17182/hepdata.27591

Differential cross sections for K − n → Σ o π o have been measured at K − momenta between 680 and 840 MeV/ c in a bubble chamber experiment. For K − n → Σ o π − the Σ o polarization was also determined. The measurements were combined with the available data on K − p → Σπ in an energy-dependent partial wave analysis in the center of mass energy range from 1520 to 1745 MeV. An acceptable fit was obtained with the well established resonances.

1 data table

FULL DETAILS OF THIS EXPERIMENT ARE IN V. HEPP ET AL., NP B115, 82 (1976), THE RECORD OF WHICH CONTAINS THE TABULATED TOTAL AND DIFFERENTIAL CROSS SECTIONS, POLARIZATIONS AND LEGENDRE POLYNOMIAL COEFFICIENTS.


Amplitude Analysis for the Process K- p --> (pi+ pi-) S-Wave Sigma0 (1385)

The Amsterdam-CERN-Nijmegen-Oxford collaboration Barreiro, F. ; Zalewski, K. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 66 (1977) 197-201, 1977.
Inspire Record 110387 DOI 10.17182/hepdata.27588

Transversity amplitudes and spin density matrix elements are determined for the process K − p → (π + π − ) s-wave ϵ 0 (1385). Predictions of the additive quark model and of duality diagrams are tested and found consistent with the data; this is the first information about the applicability of these models to processes where a scalar object is produced at the mesonic vertex.

1 data table

No description provided.