Lamsa, J.W.
Photoproduction
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High-Energy Photoproduction of pi0 Mesons from Hydrogen

DeWire, J.W. ; Jackson, H.E. ; Littauer, Raphael ;
Phys.Rev. 110 (1958) 1208-1209, 1958.
Inspire Record 944997 DOI 10.17182/hepdata.26907

None

1 data table
Table 1

No description provided.


Photoproduction of pi0 Mesons from Hydrogen in the Region 900 to 1200 Mev

Jackson, H.E. ; DeWire, J.W. ; Littauer, R.M. ;
Phys.Rev. 119 (1960) 1381-1384, 1960.
Inspire Record 944989 DOI 10.17182/hepdata.26849

The reaction γ+p→π0+p has been studied in three adjacent 100-Mev energy intervals between 900 and 1200 Mev and at pion center-of-mass angles of 47°, 90°, and 125°. The reaction was observed as a coincidence between the recoil proton and one of the photons from the meson's decay. The kinematics were determined by the energy of the incident photon and the angle of the recoil proton. The differential cross sections at the forward and backward angles show pronounced maxima near 1050 Mev, while the 90° cross sections decrease slowly with energy. The estimated total cross sections suggest a narrow maximum near 1050 Mev. These features are consistent with the previously proposed existence of a resonant state in the pion-nucleon system of total angular momentum 52.

1 data table
Table 1

No description provided.


Photoproduction of pi0 Mesons from Hydrogen near Zero Degrees

Highland, V.L. ; DeWire, J.W. ;
Phys.Rev. 132 (1963) 1293-1297, 1963.
Inspire Record 944974 DOI 10.17182/hepdata.26730

We report measurements of the differential cross section for photoproduction of π0 mesons from hydrogen, with the pion emerging near 0 deg, in the photon energy range 290 to 700 MeV. The results show no unusual behavior of the cross section in the forward direction. They are consistent with the angular distribution characteristic of a magnetic-dipole transition to a P32 state. The results agree reasonably well with theoretical predictions of Gourdin and Salin, but disagree with a prediction of DeTollis and Verganelakis. Least-squares fits in powers of cosθ have been made to the available angular distributions.

1 data table
Table 1

No description provided.


THE REACTION e p ---> e p omega0

Linnemann, J.T. ; Ahrens, L.A. ; Berkelman, Karl ; et al.
Phys.Rev.Lett. 41 (1978) 1266, 1978.
Inspire Record 129525 DOI 10.17182/hepdata.20864

The production of the ω meson by virtual photons has been measured as a function of Q2 and W. The ratio of ω production to ρ0 production is independent of Q2 in contrast to indications at lower values of W.

1 data table
Table 1

No description provided.


EXCLUSIVE RHO PRODUCTION BY VIRTUAL PHOTONS

Ahrens, L.A. ; Berkelman, Karl ; Cassel, D.G. ; et al.
Phys.Rev.Lett. 42 (1979) 208, 1979.
Inspire Record 129526 DOI 10.17182/hepdata.20809

The cross section for production of ρ0 mesons has been measured in the reaction e+p→e+p+π++π−. The cross section is presented as a function of W, the c.m. energy of the virtual-photon-proton system, and -Q2, the square of the virtual-photon mass. The vector-dominance model is not able to describe the dependence of the cross section on the parameters Q2 and W. The slope parameter B describing the scattering of the proton exhibits a significant variation with Q2.

1 data table
Table 1

No description provided.


CROSS-SECTIONS AND POSSIBLE RESONANCES IN P ANTI-P ELECTROPRODUCTION

Gibbard, B.G. ; Ahrens, L.A. ; Berkelman, Karl ; et al.
Phys.Rev.Lett. 42 (1979) 1593-1596, 1979.
Inspire Record 146169 DOI 10.17182/hepdata.20810

The cross section for the fully constrained reaction ep→eppp¯ has been determined as a function of the electroproduction variables Q2 and s, in the range 0.7<Q2<3 GeV2 and 8<s<16 GeV2. Evidence is presented and cross-section estimates are made for resonances in the final-state p¯p system.

2 data tables
Table 1

The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.

Table 2

The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.


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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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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PHOTON MULTIPLICITY AND ENERGY FRACTION OF THE UPSILON (4S) AND NEAR CONTINUUM

Chen, A. ; Goldberg, M. ; Horwitz, N. ; et al.
PRINT-83-0720, 1983.
Inspire Record 191581 DOI 10.17182/hepdata.12129

None

2 data tables
Table 1

CHARGED HADRON MEASUREMENTS ARE TAKEN FROM R.A. PERCHANOK, PHD THESIS, CORNELL UNIVERSITY (1983).

Table 2

CHARGED HADRON MEASUREMENTS ARE TAKEN FROM G.J. RUCINSKI, PHD THESIS, CORNELL UNIVERSITY (1983).


EXCLUSIVE PRODUCTION OF K+ K- pi+ pi- IN PHOTON-PHOTON COLLISIONS

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Armitage, J.C. ; et al.
Phys.Rev.Lett. 54 (1985) 2564, 1985.
Inspire Record 213402 DOI 10.17182/hepdata.20345

We report a measurement of the reaction γγ→K+K−π+π− in both tagged and untagged events at PEP. The cross section rises with invariant γγ mass to about 15 nb at 2 GeV and falls slowly at higher masses. We find clear evidence for the processes γγ→φπ+π− and γγ→K*0(892)Kπ. Upper limits (95% C.L.) of 1.5 and 5.7 nb in the mass range from 1.7 to 3.7 GeV are obtained for φρ0 and K*0K¯*0 production, respectively.

8 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

Untagged sample, (non-resonant).

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