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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
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Possible Evidence for K* (1420) Decay Into K* (890) pi pi

Goldberg, Jacques ;
Lett.Nuovo Cim. 17 (1976) 253, 1976.
Inspire Record 3513 DOI 10.17182/hepdata.37428

None

1 data table
Table 1

No description provided.


Polarization in Elastic Scattering of pi+, K+ Mesons and Protons on Protons at 45-GeV/c

The Serpukhov-Saclay-Dubna-Moscow collaboration Bruneton, C. ; Bystricky, J. ; Gaidot, A. ; et al.
Sov.J.Nucl.Phys. 25 (1977) 198, 1977.
Inspire Record 108993 DOI 10.17182/hepdata.19052
1 data table
Table 1

No description provided.


Cross-Sections and Charged Particle Multiplicities in pi+ p and p p Collisions at 60-GeV/c

Bromberg, C. ; Ferbel, T. ; Jensen, T. ; et al.
Phys.Rev.D 15 (1977) 64, 1977.
Inspire Record 108488 DOI 10.17182/hepdata.24538

We have measured charged-particle multiplicities and elastic and inelastic cross sections for π+p and pp interactions at 60 GeV/c. The data are from a 30 000-picture exposure of the 30-inch bubble chamber to a tagged but unseparated positive-particle beam at Fermilab. The low-order moments of the inelastic multiplicity distributions for all charged particles are 〈n〉 = 5.60±0.09, f2 = 0.96±0.31, and 〈n〉D = 2.19±0.06 for pp reactions and 〈n〉6.23±0.10, f2 = 1.63±0.37, and 〈n〉D = 2.22±0.06 for π+p collisions.

3 data tables
Table 1

NORMALIZED TO A TOTAL CROSS SECTION OF 38.3 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.

Table 2

NORMALIZED TO A TOTAL CROSS SECTION OF 23.2 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.

Table 3

FORWARD CROSS SECTIONS ARE CONSISTENT WITH OPTICAL POINT FOR PURELY IMAGINARY ELASTIC AMPLITUDES.


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
Table 1

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

Table 2

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

Table 3

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


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
Table 1

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

Table 2

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

Table 3

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
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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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
Table 1

No description provided.

Table 2

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.

Table 3

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

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Rho Production by Virtual Photons

Joos, P. ; Ladage, A. ; Meyer, H. ; et al.
Nucl.Phys.B 113 (1976) 53-92, 1976.
Inspire Record 108749 DOI 10.17182/hepdata.35708

The reaction γ V p → p π + π − was studied in the W , Q 2 region 1.3–2.8 GeV, 0.3–1.4 GeV 2 using the streamer chamber at DESY. A detailed analysis of rho production via γ V p→ ϱ 0 p is presented. Near threshold rho production has peripheral and non-peripheral contributions of comparable magnitude. At higher energies ( W > 2 GeV) the peripheral component is dominant. The Q 2 dependence of σ ( γ V p→ ϱ 0 p) follows that of the rho propagator as predicted by VDM. The slope of d σ /d t at 〈 Q 2 〉 = 0.4 and 0.8 GeV 2 is within errors equal to its value at Q 2 = 0. The overall shape of the ϱ 0 is t dependent as in photoproduction, but is independent of Q 2 . The decay angular distribution shows that longitudinal rhos dominate in the threshold region. At higher energies transverse rhos are dominant. Rho production by transverse photons proceeds almost exclusively by natural parity exchange, σ T N ⩾ (0.83 ± 0.06) σ T for 2.2 < W < 2.8 GeV. The s -channel helicity-flip amplitudes are small compared to non-flip amplitudes. The ratio R = σ L / σ T was determined assuming s -channel helicity conservation. We find R = ξ 2 Q 2 / M ϱ 2 with ξ 2 ≈ 0.4 for 〈 W 〉 = 2.45 GeV. Interference between rho production amplitudes from longitudinal and transverse photons is observed. With increasing energy the phase between the two amplitudes decreases. The observed features of rho electroproduction are consistent with a dominantly diffractive production mechanism for W > 2 GeV.

10 data tables
Table 1

DIPION CHANNEL CROSS SECTION.

Table 2

THE TOTAL CROSS SECTION WAS OBTAINED BY THE AUTHORS FROM A FIT TO THE SINGLE ARM DATA OF S. STEIN ET AL., PR D12, 1884 (1975).

Table 3

No description provided.

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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
Table 1

SCALE UNCERTAINTY 20 PCT IS INCLUDED IN ERROR.

Table 2

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.

Table 3

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