Cowan, C.A
SLOPE
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Exclusive $\rho^0$ and $\phi$ Production in Deep Inelastic Muon Scattering

The European Muon collaboration Ashman, J. ; Badelek, B. ; Baum, G. ; et al.
Z.Phys.C 39 (1988) 169, 1988.
Inspire Record 252743 DOI 10.17182/hepdata.15619

Data are presented on exclusive ρ0 and ϕ production in deep inelastic muon scattering from a target consisting mainly of nitrogen. The ratio of the total cross sections for ρ0 and ϕ production is found to be 9∶(1.6±0.4) at 〈Q2〉=7.5 GeV2, consistent with theSU(3) prediction of 9∶2. Thet dependence for exclusive ρ0 production is found to become shallover asQ2 increases and, for largeQ2, thet dependence is typical of that for a hard scattering process. Furthermore, the ratio of the cross sections for coherent: incoherent production from nitrogen is found to decrease rapidly withQ2. Such behaviour indicates that even for exclusive vector meson production the virtual photon behaves predominantly as an electromagnetic probe.

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Test of S Channel Helicity Conservation in Inelastic $\rho^0$ Diffraction in 20-{GeV} Photoproduction

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.D 32 (1985) 2288, 1985.
Inspire Record 209692 DOI 10.17182/hepdata.23546

The reaction γp→ρfast0pπ+π− has been studied with the linearly polarized 20-GeV monochromatic photon beam at the SLAC Hybrid Facility to test the prediction of s-channel helicity conservation in inelastic diffraction for t’<0.4 (GeV/c)2. In a sample of 1934 events from this reaction, the ρ0 decay-angular distributions and spin-density-matrix elements are consistent with s-channel helicity conservation, the π+π− mass shape displays the same skewing as seen in the reaction γp→pπ+π−, and the pπ+π− mass distribution compares well and scales according to the vector dominance model with that produced in π±p→πfast±pπ+π−.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

SPIN DENSITY MATRIX ELEMENTS FOR THE DIFFRACTIVE RHO0 MESON FROM STUDY OF THE ANGULAR DISTRIBUTIONS. CORRECTION HAS BEEN MADE FOR THE (20 +- 5) PCT NON DIFFRACTIVE BACKGROUND IN THE FINAL DATA SAMPLE, ASSUMING IT TO HAVE AN ISOTOPIC ANGULAR DISTRIBUTION.


Study of the $\rho^\prime$ (1600) Mass Region Using $\gamma p \to \pi^+ \pi^- p$ at 20-{GeV}

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.Lett. 53 (1984) 751, 1984.
Inspire Record 201710 DOI 10.17182/hepdata.20387

We have observed the π+π− decay of the ρ′(1600) in the production reaction γp→ρ′p at 20 GeV. Using a calculation which takes into account the interference of the ρ′ with the ρ(770) and a Drell background, we find good evidence that this resonance is a radial excitation of the ρ(770). The background interference strongly distorts the angular distributions predicted by a purely s-channel helicity-conserving production mechanism. We measure m0=(1.55±0.07) GeV/c2 and Γ0=(0.28−0.08+0.03) GeV/c2.

4 data tables
Table 1

SLOPE VARIATION WITH M(PI+ PI-) IN THE RANGE 0.4 TO 2.5 GEV.

Table 2

No description provided.

Table 3

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Elastic Photon Proton Scattering in the 50-{GeV} - 130-{GeV} Range

Breakstone, A.M. ; Cheng, D.C. ; Dorfan, D.E. ; et al.
Phys.Rev.Lett. 47 (1981) 1778-1781, 1981.
Inspire Record 173082 DOI 10.17182/hepdata.20627

In the tagged-photon beam at Fermilab, differential cross sections were measured for the elastic scattering of photons on a liquid-hydrogen target. The diffractive forward peak was measured for photon energies between 50 and 130 GeV and |t| values between 0.07 and 1.20 (GeV/c)2. The shape of the diffraction peak is similar to that seen in π−p scattering. The magnitude is that predicted by the optical theorem.

3 data tables
Table 1

No description provided.

Table 2

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Table 3

No description provided.


OBSERVATION OF THE REACTION K- P ---> B- Y*+ AT 8.25-GeV/c

The BIRMINGHAM-CERN-GLASGOW-MICHIGAN STATE-PARIS collaboration Bloodworth, I.J. ; Carney, J.N. ; Cowan, C.A. ; et al.
Lett.Nuovo Cim. 27 (1980) 555-561, 1980.
Inspire Record 157726 DOI 10.17182/hepdata.37367

None

4 data tables
Table 1

No description provided.

Table 2

DOMINANT NATURAL PARITY EXCHANGE.

Table 3

EVIDENCE FOR FORWARD DIP FOR -TP < 0.1 GEV**2.

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Exclusive Vector Meson Production in Muon - Proton Scattering

del Papa, C. ; Dorfan, David E. ; Flatte, Stanley M. ; et al.
Phys.Rev.D 19 (1979) 1303, 1979.
Inspire Record 130570 DOI 10.17182/hepdata.24312

From a muon-proton scattering experiment with a streamer chamber at the Stanford Linear Accelerator we present results in the ranges 0.3<Q2<4.7 GeV2 and 1.7<W<4.7 GeV for the reactions μ+p→μpV where V is a vector meson (ρ0, ω, or φ). It is shown that in ρ production the skewing parameter and the longitudinal-transverse ratio change significantly as Q2 increases above 1 GeV2. The cross section for ρ0 production as a function of Q2 falls below the vector-meson-dominance prediction. The ratio of the cross section for exclusive vector-meson production to the total cross section falls by a factor of 10 between photoproduction and a Q2 of 2 GeV2, yet the ratio of ω to ρ production remains constant at the photoproduction value out to Q2>2 GeV2.

4 data tables
Table 1

THE ABSOLUTE TOTAL CROSS SECTION IS FROM A FIT TO THE MIT-SLAC ELECTRON SCATTERING DATA BY W. ATWOOD AND S. STEIN.

Table 2

No description provided.

Table 3

FOR 0.6 < M(PI+ PI-) < 0.9 GEV, USING THE METHOD OF MOMENTS.

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The Slope of Forward Elastic pi+ p Scattering from 4.4-GeV/c to 6.0-GeV/c

Rey, C.A. ; Poirier, J.A. ; Lennox, Arlene J. ; et al.
Phys.Rev.D 15 (1977) 59, 1977.
Inspire Record 109729 DOI 10.17182/hepdata.24605

Angular distributions for π+p→π+p were measured for 13 incident-pion momenta from 4.4 to 6.0 GeV/c and for −t less than ∼0.1 (GeV/c)2. This experiment was performed at the Zero Gradient Synchrotron of Argonne National Laboratory, where a focusing magnetic spectrometer and a scintillation-counter hodoscope were used. In fitting the angular distributions the strong-interaction contribution was parameterized by an exponential form exp(bt); the Coulomb interference was also included. The resulting values of the slope parameter for |t|<∼0.1 (GeV/c)2 are presented for each incident beam momentum.

2 data tables
Table 1

ENLARGED GRAPHS OF FIGURES SUPPLIED BY J. A. POIRIER.

Table 2

SLOPE IS FROM FITTING EXP(SLOPE*T) TO FORWARD DIFFERENTIAL CROSS SECTION FOR -T < 0.1 GEV**2 APPROX AFTER ALLOWING FOR COULOMB INTERACTION.


$\pi^+ p$ Backward Elastic Scattering from 2-GeV/c to 6-GeV/c

Lennox, Arlene J. ; Baker, W.F. ; Eartly, David P. ; et al.
Phys.Rev.D 11 (1975) 1777, 1975.
Inspire Record 90923 DOI 10.17182/hepdata.24918

The backward angular distributions obtained in an experiment at the Zero Gradient Synchrotron of Argonne National Laboratory were used to systematically study the energy dependence of the 180° differential cross section for π+p elastic scattering in the center-of-mass energy region from 2159 to 3487 MeV. At each of 38 incident pion momenta between 2.0 and 6.0 GeV/c, a focusing spectrometer and scintillation counter hodoscopes were used to obtain differential cross sections for typically five pion scattering angles from 141° to 173° in the laboratory. Values for dσdΩ at 180° were then obtained by extrapolation. A resonance model and an interference model were used to perform fits to the energy dependence of dσdΩ (180°). Both models led to good fits to our data and yielded values for the masses, widths, parities, and the product of spin and elasticity for the Δ(2200), Δ(2420), Δ(2850), and Δ(3230) resonances. Our data confirm the existence of the Δ(3230) and require the negative-parity Δ(2200).

39 data tables
Table 1

No description provided.

Table 2

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Table 3

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The Energy Dependence of Backward $\pi^+ p$ Elastic Scattering from 2 GeV/c to 6 GeV/c

Baker, W.F. ; Eartly, David P. ; Pretzl, K. ; et al.
Phys.Rev.Lett. 32 (1974) 251, 1974.
Inspire Record 80709 DOI 10.17182/hepdata.21310

The energy dependence of backward π+p elastic scattering has been measured for incident π momenta 2.0-6.0 GeV/c in steps of typically 100 MeV/c. Values are presented for both the differential cross section extrapolated to 180° and the slope of the backward peak as a function of momentum. In the s channel we see the effects of the established Δ++ resonances and evidence for the Δ(3230). Also, the data show the existence of a negative-parity Δ resonance with mass ∼2200 MeV/c2.

1 data table
Table 1

No description provided.