Highlights of the Reaction $\pi^- p \to \pi^- \pi^+ n$ at 100-{GeV}/$c$ and 175-{GeV}/$c$

Bromberg, C. ; Dickey, J.O. ; Fox, G.C. ; et al.
Phys.Rev.D 29 (1984) 588, 1984.
Inspire Record 13822 DOI 10.17182/hepdata.33875

We present a summary of the physics results from an experimental study of the reaction π−p→π−π+n at 100 and 175 GeV/c incident-beam momentum. Our data show the continuing dominance of one-pion exchange in these reactions with the characteristic 1Plab2 momentum dependence. We extract the pion Regge trajectory from our data on π−p→ρ0n and study the zero structure of the ππ differential cross section up to sππ=12 GeV2.

9 data tables

No description provided.

No description provided.

SPHERICAL HARMONIC MOMENTS.

More…

Measurement and Analysis of the Reaction $\pi^- p \to \rho^0 n$ on a Polarized Target

The CERN-Munich collaboration Becker, H. ; Blanar, G. ; Blum, W. ; et al.
Nucl.Phys.B 150 (1979) 301-325, 1979.
Inspire Record 132603 DOI 10.17182/hepdata.34819

The reaction π − p→ π + π − n has been measured in a high-statistics experiment on a transversely polarized proton target at 17.2 GeV, and unexpectedly large nucleon polarization effects have been observed. Combining the results of this experiment with a measurement on a hydrogen target allows a model-independent partial-wave analysis in terms of the “nucleon transversity” amplitudes. Unique or at most twofold ambiguous solutions are obtained. In particular we find a high lower limit ( ⪆30% ) of the spin non-flip unnatural exchange amplitudes at low | t |. These amplitudes, interpreted as being due to the exchange of an object with the quantum numbers of the A 1 , have been assumed to be absent in previous analyses. In checking the consequences of this finding on the old results, we test the validity of the rank-two assumotions for the density matrix. We find a small but significant deviation, which shows the need for a new phase-shift analysis including the A 1 exchange contribution.

2 data tables

MASS DEPENDENCE OF NORMALIZED T-CHANNEL MOMENTS SCALED TO 100 PCT POLARIZED PROTONS.

T DEPENDENCE OF NORMALIZED T-CHANNEL MOMENTS IN THE RHO REGION SCALED TO 100 PCT POLARIZED PROTONS.


Baryon Exchange in 12-GeV/c pi- p Interactions

Arenton, M.W. ; Bacino, W.J. ; Hauptman, J.M. ; et al.
Nucl.Phys.B 141 (1978) 77-100, 1978.
Inspire Record 136191 DOI 10.17182/hepdata.34942

Final states produced by charged baryon exchange in π − p interactions at 12 GeV/ c laboratory momentum have been studied. Forward neutrons with momenta determined by a calorimeter to be greater than 8.5 ± 1.4 GeV/ c triggered the SLAC 40-inch hydrogen bubble chamber which operated at a 10 Hz expansion rate. We report data on the reactions π − p→n π − π + , π − p→n π − π + π 0 , and π − p→n π − π − π + π + . In π − n π − p→n π + , production of ϱ and f mesons is observed. Differential cross sections are derived and compared with data at lower incident momentum and with theoretical models. In π − p→n π − π + π 0 , ω production is observed with a differential cross section having a deep near u ′= 0.2 (GeV/ c ) 2 . In π − p→n π − π − π + π + , Δ − , ϱ and f production is observed . The observed mass distributions appear to indicate the production of wide resonaces decaying into ϱππ. Some evidence for ϱ-ω interference is also observed.

14 data tables

No description provided.

No description provided.

CORRECTED FOR BACKGROUND.

More…

Backward Resonance Production in pi- p --> n pi+ pi- at 8-GeV/c

Eisenstein, Bob I. ; Elliott, J. ; Mollet, W. ; et al.
Phys.Rev.D 18 (1978) 1370-1381, 1978.
Inspire Record 136306 DOI 10.17182/hepdata.24374

We have studied backward meson and baryon production in π−p→nπ+π− at 8 GeV/c using a streamer chamber triggered by the detection of the interaction of the neutron in thick-plate optical spark chambers. Our data sample of 866 events is dominated by the quasi-two-body final states Δ−(1232)π+, nρ0, and nf0. We study the differential and total backward cross sections for these states and the decay angular distributions of the resonances. The results for the Δ− and ρ0 indicate that both nucleon and Δ exchange in the u channel are important in their production, while f0 production is, as expected, consistent with nucleon exchange.

5 data tables

No description provided.

BACKWARD DIP.

No description provided.

More…

Comparative Study of rho0, omega, K* (890) and anti-K* (890) Production by Charge Exchange

Wicklund, A.B. ; Ayres, D.S. ; Diebold, R. ; et al.
Phys.Rev.D 17 (1978) 1197, 1978.
Inspire Record 120816 DOI 10.17182/hepdata.24436

We present cross sections and density-matrix elements from a high-statistics study of the reactions π−p→ρ0n, K−p→K¯*0(890)n, and K+n→K*0(890)p, at 3, 4, and 6 GeV/c and four-momentum transfer squared to the recoil nucleon −t<~0.9 GeV2. The experiment was carried out at the Argonne Zero Gradient Synchrotron using the effective-mass spectrometer. In the same experiment, we have measured the ρ−ω interference cross sections by comparison of the two reactions π−p→π−π+n and π+n→π+π−p, to which the interference terms contribute with opposite signs. We examine the systematics of ρ0 production: In the s channel we find little shrinkage with energy of the helicity-0 cross sections, which are presumably dominated by π exchange; the helicity-1 cross sections exhibit considerable shrinkage for unnatural-parity exchange, and antishrinkage for natural-parity exchange. The K*0 and K¯*0 production observables exhibit significant differences, especially in the helicity-1 states. These differences are due to interference between even- and odd-G-parity exchange amplitudes and they are related by SU(3) symmetry to ρ−ω interference effects and to the ρ0 and ω production observables. It is shown that exchange-degeneracy-breaking effects satisfy SU(3) symmetry and can be explained qualitatively in the frame-work of SU(3)-symmetric, strongly absorbed Regge-pole models. The results of our amplitude analysis are compared with previous phenomenological analyses and model predictions.

9 data tables

No description provided.

No description provided.

No description provided.

More…

Production of rho0 and f in pi- p Interactions at 16-GeV/c and Separation Into Fragmentation and Central Components

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg-Warsaw collaboration Bartke, J. ; Kirk, H. ; Sixel, P. ; et al.
Nucl.Phys.B 107 (1976) 93-117, 1976.
Inspire Record 108513 DOI 10.17182/hepdata.8729

The production of ρ 0 (770) and f(1270) is studied in π − p interactions at 16 GeV/ c . By comparison with inclusive K ∗0 production in the reaction K − p → K ∗0 + anything, and with inclusive ρ 0 production in the reaction pp → ρ 0 + anything, it is found that the data can be interpreted in terms of two production processes: the central production of resonances and the fragmentation of the beam particle. For the π − p reaction, the inclusive ρ 0 beam fragmentation cross section is 3.1 ± 0.3 mb while that for central production is 1.6 ± 0.5 mb. The ρ 0 central production cross section is consistent with increasing with energy as ln s behaviour. The ratio of ρ 0 to π − inclusive cross sections (excluding the leading π − ) is ∼0.2, independent of energy. The ρ 0 to π − ratio increases as a function of p T to a constant value of ∼ 1 2 above 1 GeV/ c . The ρ (charged and neutral) and f decays account for (25 ± 4)% and (1.4 ± 0.3)%, respectively, of all pions produced.

7 data tables

No description provided.

No description provided.

No description provided.

More…

pi- C-12 Interactions at E(pi) = 40-GeV and the Hypothesis About Hadron Clusters

Inogamova, T.Ya. ; Kalinkin, B.N. ; Lyubimov, V.B. ; et al.
Sov.J.Nucl.Phys. 22 (1975) 291, 1975.
Inspire Record 91364 DOI 10.17182/hepdata.19081

None

1 data table

No description provided.


pi pi Scattering and pi+ d Interactions at 7-GeV/c

Carroll, J.T. ; Matthews, J.A.J. ; Walker, W.D. ; et al.
Phys.Rev.D 10 (1974) 1430, 1974.
Inspire Record 91650 DOI 10.17182/hepdata.25036

Using bubble-chamber data on the reactions π+d→pspπ0π0, π+d→pspπ+π−, and π−p→nπ+π− at 7 GeV/c incident π momentum, π−π phase shifts are determined for 0.6<M(ππ)<1.5 GeV/c2. An I=0S-wave resonance is observed in the f0 peak region of M(ππ). Constructive ρ−ω interference is found in the reaction π+n→pπ+π− and evidence is presented for some specifically deuteron effects in the data with large spectator-proton momentum.

6 data tables

TWO-PRONG CROSS SECTIONS IN DEUTERIUM WITH SPECTATOR PROTON MOMENTUM CUT AT 0.3 GEV/C.

NOTE THAT THE LOW-T DATA POINTS (<0.1 GEV**2) SHOULD BE CORRECTED FOR PAULI EXCLUSION IN DEUTERIUM.

FROM FIT WITH BREIT-WIGNER RESONANCES PLUS PHASE SPACE.

More…

An Investigation of rho Meson Production in pi p Interactions at 3.9-GeV/c

Haber, B. ; Hodous, M.F. ; Hulsizer, R.I. ; et al.
Phys.Rev.D 10 (1974) 1387, 1974.
Inspire Record 819 DOI 10.17182/hepdata.25008

We have investigated the ρ-meson production mechanism in the three reactions π±p→ρ±p and π−p→ρ0n at 3.9 GeV/c (s=8.2 GeV2) using the prism-plot technique. Differential cross sections at all momentum transfers are presented. A significant backward peak has been found in all three reactions. The differential cross sections for these backward peaks are given and are compared with the equivalent pion elastic and charge-exchange cross sections in the backward direction. Using a linear combination of the three differential cross sections we have isolated the I=0 exchange contribution in the forward direction. This differential cross section has a zero at −t=0.45 (GeV/c)2 and is fitted by the dual absorptive model of Harari with an interaction radius of ∼ 1.2 F. The total I=0 cross section is calculated and compared with similarly determined cross sections at higher momenta. An analysis of the properties of the other possible spin-parity exchanges is also presented.

8 data tables

SLOPE FITTED OVER 0.05 < -T < 0.3 GEV**2.

No description provided.

No description provided.

More…

Two-prong fitted channels at 11.7 gev/c

Evans, D. ; Neat, K. ; Caso, C. ; et al.
Nuovo Cim.A 16 (1973) 299-314, 1973.
Inspire Record 87004 DOI 10.17182/hepdata.37784

A sample of 43000 two-prong events obtained at a momomentum of 11.7 GeV/c is used to determine the cross-sections of the fitted channels, and to study the reaction π+p→π+pπ0. We investigate in particular the quasi-two-body channels π0Δ++ and ρ+p.

6 data tables

No description provided.

No description provided.

No description provided.

More…