Barbarino, G.
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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.


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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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.


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
Table 1

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


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
Table 1

No description provided.

Table 2

No description provided.


Measurement of the Branching Ratio gamma (anti-p p --> e+ e-) / gamma (anti-p p --> Total) in anti-Proton-Proton Annihilation at Rest

Bassompierre, G. ; Binder, G. ; Dalpiaz, P. ; et al.
Phys.Lett.B 64 (1976) 475-478, 1976.
Inspire Record 109375 DOI 10.17182/hepdata.27616

Analyzing a sample of 220 000 events from an experiment still in progress at the CERN Proton Synchrotron (PS), 60 pairs of electrons with an energy above 700 MeV have been observed. The electrons, produced by annihilation of antiprotons stopped in a liquid-hydrogen target, are detected with optical spark chambers and scintillation counters. Twenty-nine out of these 60 pairs have been found to be collinear; normalizing with respect to the hadronic two-body channels π + π − and K + K − , a braching ratio B ee =Γ( p ̄ p → e + e − )/Γ( p ̄ p → total ) = (3.2 ± 0.9) × 10 −7 has been obtained

1 data table
Table 1

No description provided.


Energy Dependence of the Reactions K0(L) p --> K0(s) p, pi+ Lambda, pi+ Sigma0 from 1540-MeV to 1610-MeV

Engler, A. ; Keyes, G. ; Kraemer, R.W. ; et al.
Phys.Lett.B 63 (1976) 231-234, 1976.
Inspire Record 3809 DOI 10.17182/hepdata.27639

The reactions K L o p→K S o p, π + Λ , π + Σ o have been measured for center-of-mass energies from 1540 to 1610 MeV. Channel cross sections and coefficients of the Legendre polynomial expansion of the differential cross sections and hyperon polarizations are presented. We see no evidence in the πΛ channel for the suggested 3 2 − resonance at 1580 MeV. The cross section for the K S o p channel shows an energy dependence which is not predicted by the existing phase shift solutions based on charged kaon data.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Some 0- 1/2+ and 0- 3/2+ Final States in K- p Reactions at 14.3-GeV/c

Chaurand, B. ; Drevillon, B. ; Gago, J.M. ; et al.
Nucl.Phys.B 117 (1976) 1, 1976.
Inspire Record 109200 DOI 10.17182/hepdata.35604

We present data on K − p reactions leading to the final states K 0 n , π 0 Λ, ηΛ, η'Λ, π − Σ + , K 0 Δ 0 (1230), and π − Σ + (1385) from a bubble chamber experiment at 14.3 GeV/ c K − lab momentum. Total and differential cross sections, Λ and Σ ∓ polarisations in π 0 Λ and π − Σ + final states as well as the Σ + (1385) density matrix elements are given.

9 data tables
Table 1

NORMALIZED TO A TOTAL CROSS SECTION OF 21.5 +- 0.2 MB (GALBRAITH ET AL, PR 138B, 913 (1965)).

Table 2

No description provided.

Table 3

No description provided.

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PRISM Plot Analysis of the Reaction pi- p --> p pi+ pi- pi- at 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg-Warsaw collaboration Grassler, H. ; Honecker, R. ; Kirk, H.G. ; et al.
Nucl.Phys.B 113 (1976) 365-377, 1976.
Inspire Record 109661 DOI 10.17182/hepdata.35583

A prism plot analysis of the reaction π − p→p π + π − π − at 16 GeV/ c has been made and the results are compared with those obtained in a similar analysis of the reaction π + p→ p π + π + π − at the same energy. The three dominating reaction mechanisms (pion dissociation, reggeon exchange, proton diffraction dissociation) appear to be well separated, while considerable residual overlaps are present inside these classes. The prism plot method is discussed as a means for detecting hidden structures and some evidence is presented for a broad three-pion enhancement around 2 GeV decaying primarily into ϱ 0 π − .

2 data tables
Table 1

No description provided.

Table 2

A4(1900) IS CALLED A*(1800) BY AUTHORS. PI+ P CROSS SECTIONS PREVIOUSLY PUBLISHED IN M. DEUTSCHMANN ET AL., NP B99, 397 (1975).