Axon, T.J.
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Photoproduction of $\pi \Delta(1232)$ From Hydrogen in the Energy Range 2.4-{GeV} to 4.8-{GeV}

The LAMP2 Group collaboration Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.
Z.Phys.C 6 (1980) 93, 1980.
Inspire Record 153944 DOI 10.17182/hepdata.14328

We present differential cross sections andΔ++ spin density matrix elements for the photoproduction processγp→π−Δ++ and differential cross sections for the processγp→π+Δ0. The incident photon energy dependence is studied and a comparison is made with previous experiments and with the predictions of a theoretical model.

5 data tables
Table 1

DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.

Table 2

DIFFERENTIAL CROSS SECTION AVERAGED OVER WHOLE ENERGY RANGE.

Table 3

DIFFERENTIAL CROSS SECTION FOR DIFFERENT ENERGY RANGES.

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Strangeness Exchange in the Photoproduction of $K^+ \Lambda$ (1520) Between 2.8-{GeV} and 4.8-{GeV}

Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.
Z.Phys.C 7 (1980) 17, 1980.
Inspire Record 153887 DOI 10.17182/hepdata.14096

A tagged photon beam (2.8<Eγ<4.8 GeV) and multiparticle spectrometer have been used to study the photoproduction in hydrogen ofK+Λ(1520). Precise values for the mass and width of the Λ(1520) are given. The total cross-section is found to fall with increasing photon energy like (6.5±0.7)Eγ−(2.1±0.2) μb. The differential cross sectiondσ/dt indicates peripheral forward production and exhibits no evidence for shrinkage when compared with higher energy data. The Λ(1520) spin density matrix shows thatK exchange alone cannot account for the production mechanism. The reaction is found to resemble the process γp→K+ Λ(1115) in all measurable respects.

3 data tables
Table 1

FITTED CROSS SECTION ENERGY DEPENDENCE IS SIG = (6.7 +- 0.7 MUB*GEV**2) * P**(-2.1 +- 0.2), INCLUDING HIGHER ENERGY DATA.

Table 2

EXPONENTIAL SLOPE IS 6.1 +- 2.0 GEV**-2 FOR -T = 0.2 TO 0.7 GEV**2.

Table 3

No description provided.


Production of Muon Pairs in the Continuum Region by 39.5-{GeV}/$c \pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ Beams Incident on a Tungsten Target

Corden, M. ; Dowell, J.D. ; Garvey, J. ; et al.
Phys.Lett.B 96 (1980) 417-421, 1980.
Inspire Record 154577 DOI 10.17182/hepdata.27163

Inclusive dimuon production by 39.5 GeV/ c π ± , K ± , p and p¯ is described for masses greater than 2.0 GeV/ c 2 . The π − , π + and (π − − π + ) continuum cross-sections exceed the naive Drell-Yan predictions by a factor ∼2.4. The pion valence structure function has been measured and is consistent with a corresponding measurement at 200 GeV/ c .

1 data table
Table 1

No description provided.


Hard Scattering and $\Delta - \Delta$ Exchange in Backward Photoproduction of $\Delta^{++} \pi^-$

Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.
Phys.Lett.B 98 (1981) 135-139, 1981.
Inspire Record 156090 DOI 10.17182/hepdata.27134

A tagged photon beam and multiparticle spectrometer have been used to measure the backward photoproduction process γp → Δ ++ π − . The energy dependence of the production cross section between 2.8 and 4.8 GeV is studied and found to exhibit shrinkage in excess of that expected for Δ σ dominance. An interpretation of the production mechanism in terms of an incoherent mixture of Δ σ exchange and a “hard scattering” contribution is presented.

1 data table
Table 1

No description provided.


ELECTROPRODUCTION OF PI DELTA AND OTHER NONDIFFRACTIVE FINAL STATES

Day, C.T. ; Harding, D.J. ; Klinger, J.S. ; et al.
Phys.Rev.D 23 (1981) 576-586, 1981.
Inspire Record 166699 DOI 10.17182/hepdata.24078

This paper reports the results of an experiment measuring the parameters of various electroproduction reactions for a range in the electroproduction variables 0.7<Q2<4 GeV2 and 2<W2<16 GeV2. This report is limited to nondiffractive exclusive channels, with detailed results regarding the πΔ final states, statistically limited results for KΛ final states, and upper limits on the production of a number of event topologies containing a single unseen neutral particle.

16 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Experimental Test of the {Drell-Yan} Model in $p W \to \mu^+ \mu^- X$

Smith, S.R. ; Childress, S. ; Mockett, P.M. ; et al.
Phys.Rev.Lett. 46 (1981) 1607, 1981.
Inspire Record 164176 DOI 10.17182/hepdata.20659

We report a high-statistics study of the reaction p+W→μ++μ−+X with use of an intense 400-GeV/c proton beam, a magnetized-iron beam dump, and a wide-acceptance detector. Using data near xF=0, we have extracted the nucleon sea-quark distribution and find it to be a factor 1.6±0.3 larger than that obtained by inelastic charged-current neutrino scattering. We then compare the Drell-Yan prediction with our data including the previously unexplored region of large xF and find excellent agreement for a wide range of μ-pair invariant mass.

6 data tables
Table 1

Dimuon mass mass distribution at XFP=0.1.

Table 2

Dimuon production for varying mass as function of XFP.

Table 3

Dimuon production for varying mass as function of XFP.

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Exclusive $\rho^0$, $\omega$ and $\phi$ Electroproduction

Cassel, D.G. ; Ahrens, L.A. ; Berkelman, Karl ; et al.
Phys.Rev.D 24 (1981) 2787, 1981.
Inspire Record 166020 DOI 10.17182/hepdata.24050

We have measured exclusive ρ0, ω, and φ meson electroproduction at the Cornell Wilson Synchrotron. The final ρ0 data sample included 4637 four-constraint e+p→e+π++π−+p events, with incident energy E=11.5 GeV and electroproduction variables Q2 and W in the region 0.7<Q2<4 GeV2 and 1.9<W<4 GeV. We find that the width of the forward ρ0 diffraction peak increases rapidly as the lifetime of the intermediate hadron states decreases below cΔτ=1 fm and that the peak is wider for longitudinal ρ0 than it is for transverse ρ0. The longitudinal-transverse cross-section ratio Rp=σLσT, obtained assuming s-channel helicity conservation, becomes constant at high Q2. At fixed W the diffractive vector-meson-dominance (VMD) model reproduces the Q2 dependence of our cross section, σ=(σT+εσL), but is is not able to account for the rapid decrease in the cross section with increasing W we observe. We find that σωσρ depends on W but is independent of Q2 for 0.7<Q2<3 GeV2 and 2.2<W<3.7 GeV. However, σω is substantially larger than the diffractive VMD cross section. Our results for σφ are consistent with the Q2 dependence of the diffractive VMD model for 0.8<Q2<4 GeV2 and 2<W<3.7 GeV, but this model again fails to predict the W dependence we observe.

8 data tables
Table 1

FOUR CHANNEL FIT TO TWO PION PRODUCTION ASSUMING NO INTERFERENCE.

Table 2

DEPENDENCE OF TOTAL, LONGITUDINAL (L) AND TRANSVERSE (U) DIFFERENTIAL CROSS SECTIONS ON C*DELTA(TAU), THE FORMATION TIME FOR VIRTUAL INTERMEDIATE HADRON STATES. DELTA(TAU) IS 1/DELTA(E) WHERE DELTA(E) IS E(RF=LAB,P=3) - NU = SQRT(NU**2 + Q2 + M(RHO)**2) - NU.

Table 3

No description provided.

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A Study of Elastic Photoproduction of Low Mass K$^{+} $K$^{-}$ Pairs From Hydrogen in the Energy Range 2.8-{GeV} to 4.8-{GeV}

Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.
Z.Phys.C 12 (1982) 1, 1982.
Inspire Record 168200 DOI 10.17182/hepdata.16435

The results of an experiment to study elasticK+K− photoproduction are presented. Differential cross sections and spin density matrix elements for ϕ(1.019) production are stddied as a function of incident photon energy and over a wide range of momentum transfer,t (tmin>t>−1.5(GeV/c)2). Helicity conserving amplitudes are observed to dominate ϕ production throughout this range and the differential cross sections exhibit a forward diffractive peak which cannot be understood in terms of a simple exponential dependence. A new value of the photon ϕ coupling constant is determined and shown to be consistent withe+e− annihilation measurements. A detailed study of the energy dependence of the differential cross sections is made, including other experimental data, and the extracted effective Regge trajectory compared with other diffractive processes. A study of the dependence of theK+K− decay angular distribution on invariant mass reveals evidence for ans wave contribution interfering with thep wave ϕ which may be attributable to theS* meson.

3 data tables
Table 1

LOWER LIMIT OF ABS(T) IN TABLE IS TMIN.

Table 2

No description provided.

Table 3

LOW T VARIATION WITH ELAB. LOWER LIMIT OF ABS(T) IN TABLE IS TMIN.


Transverse Momentum Distributions of Hadrons Produced in $\alpha \alpha$ and $\alpha p$ Collisions at the {CERN} Intersecting Storage Rings

The CERN-Heidelberg-Lund collaboration Bell, W. ; Braune, K. ; Claesson, G. ; et al.
Phys.Lett.B 112 (1982) 271-276, 1982.
Inspire Record 176957 DOI 10.17182/hepdata.30920

The inclusive production of charged hadrons has been measured in αα and αp collisions at nucleon-nucleon c.m. energies (√s nn )of 31 and 44 GeV, respectively, for transverse momenta p T up to 5 GeV/ c in the central rapidity ( y ) region. at high p T the yields are consistent with being 4 times and 16 times highere than the ones in pp interactions at y =0, for αp and αα interactions, respectively. However, an enhancement over these factors, as expected from an earlier FNAL experiment, cannot be ruled out.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A MEASUREMENT OF THE A-DEPENDENCE OF THE J / PSI CROSS-SECTION BY COMPARING DATA ON HYDROGEN AND TUNGSTEN TARGETS AT 39.5-GeV/c

Corden, M.J. ; Dowell, J.D. ; Garvey, J. ; et al.
Phys.Lett.B 110 (1982) 415-418, 1982.
Inspire Record 179825 DOI 10.17182/hepdata.30977

J/ψ production on hydrogen and tungsten targets has been compared at 39.5 GeV/ c and the variation of the A -dependence of the J/ψ cross section as a function of p t 2 and x F has been measured. The A -dependence parameter, α, rises with increasing p t 2 and falls with increasing x F . Both effects are shown not to be due to the Fermi motion of nucleons in the tungsten nucleus.

2 data tables
Table 1

No description provided.

Table 2

No description provided.