HEPData Search

Showing 10 of 118 results

$\pi^+$ photoproduction on the proton for photon energies from 0.725 to 2.875 GeV

The CLAS collaboration Dugger, M. ; Ritchie, B.G. ; Ball, J.P. ; et al.

Phys.Rev.C 79 (2009) 065206, 2009.

Inspire Record 814847 DOI 10.17182/hepdata.51952

Differential cross sections for the reaction $\gamma p \to n \pi^+$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID and MAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the world data set, significant changes have occurred in the high-energy behavior of the SAID cross-section predictions and amplitudes.

11 data tables

Table 1

Differential cross sections for incident photon energies 0.725, 0.775, 0.825and 0.875 GeV.

Table 2

Differential cross sections for incident photon energies 0.925, 0.975, 1.025and 1.075 GeV.

Table 3

Differential cross sections for incident photon energies 1.125, 1.175, 1.225and 1.275 GeV.

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$\pi^+$ production with linearly polarized photons

Geweniger, C. ; Heide, P. ; Kötz, U. ; et al.

Phys.Lett.B 29 (1969) 41-44, 1969.

Inspire Record 56795 DOI 10.17182/hepdata.29060

Single π + production on protons by linearly polarized photons of 2.5 to 5 GeV was measured at squared four momentum transfers t between −0.01 and −0.6 (GeV/ c ) 2 . The results show that the differential cross section d σ ⊥ d t with the electric vector of the photon perpendicular to the reaction plane is much larger than d σ ‖ d t with the electric vector parallel to the reaction plane. The predictions of Regge models and of the vector meson dominance model are briefly discussed.

3 data tables

Table 1

Axis error includes +- 0.0/0.0 contribution (?////).

Table 2

Axis error includes +- 0.0/0.0 contribution (?////).

Table 3

Axis error includes +- 0.0/0.0 contribution (?////).

$\pi^\pm$ Meson Spectra in the Inclusive Reaction $\gamma C \to \pi X$ Caused by Bremsstrahlung $\gamma$ Quanta With the Maximum Energy 4.5-{GeV}

Alanakian, K.V. ; Amarian, M.D. ; Demirchyan, R.A. ; et al.

JETP Lett. 32 (1980) 652, 1980.

Inspire Record 158531 DOI 10.17182/hepdata.18460

None

1 data table

Table 1

DISTRIBUTIONS INTEGRATED WITH PHOTON SPECTRUM ARE NORMALIZED ON NUMBER OF EQUIVALENT PHOTONS.

A Measurement of the Cross-Section for Four Pion Production in gamma gamma Collisions at SPEAR

Burke, D.L. ; Abrams, G.S. ; Alam, M.S. ; et al.

Phys.Lett.B 103 (1981) 153-156, 1981.

Inspire Record 165016 DOI 10.17182/hepdata.31168

We present a measurement of the cross section for the reaction e + e − → e + e − π + π − π + π − at SPEAR. This channel is found to be large and dominated by the process γγ → ϱ 0 ϱ 0 → π + π − π + π − . The cross section, which is small just above the four-pion threshold, exhibits a large enhancement near the ϱ 0 ϱ 0 threshold.

1 data table

Table 1

Axis error includes +- 0.0/0.0 contribution (THE QUOTED ERRORS INCLUDE VARIOUS SYSTEMATIC ERRORS ADDED QUADRATICALLY).

A Measurement of the photon structure function F2(gamma) at an average Q2 of 12-GeV2/c**4

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 69 (1996) 223-234, 1996.

Inspire Record 396884 DOI 10.17182/hepdata.47867

None

2 data tables

Table 1

No description provided.

Table 2

Low x domain.

A Study of D* Production in High-Energy $\gamma$ p Interactions

Sliwa, K. ; Appel, J.A. ; Biel, J. ; et al.

Phys.Rev.D 32 (1985) 1053-1060, 1985.

Inspire Record 194636 DOI 10.17182/hepdata.23561

We have studied D* production mechanisms using data from a photoproduction experiment at the Fermilab Tagged Photon Spectrometer. A large sample of charged D*’s was selected via the clean signature of the cascade decay D*→D0π+ and subsequently D0→K−π+ or D0→K−π+π0. The cross section for the process γp→(D*++anything)p at an average energy of 105 GeV was measured to be 88±32 nb. Only (11±7)% of D*’s were found to be consistent with being accompanied solely by a D¯* or a D¯; the remaining events contain additional particles. The distribution of the production angle of the D* in the photon-fragmentation-system center of mass is strongly anisotropic and consistent with the form f(θ*)=cos4θ*. We set a limit on the associated-production-process cross section σ(γp→(D¯*−+anything)Λc) x)<60 nb (90% C.L.).

2 data tables

Table 1

No description provided.

Table 2

No description provided.

A Study of the Inclusive $K_s^0$, $\Lambda$, $\bar{\Lambda}$ Production in Diffractive $\gamma$P Interactions

Bhadra, S. ; Appel, J.A. ; Bartlett, D.F. ; et al.

Phys.Rev.Lett. 55 (1985) 2749, 1985.

Inspire Record 217669 DOI 10.17182/hepdata.20275

We have studied inclusive KS, Λ, and Λ¯ photoproduction over the ranges 40<Eγ<170 GeV and forward produced mass 2<MF<10 GeV. We observe equal Λ and Λ¯ production rates and spectra as expected in a diffractive process where the target proton remains unaltered. We show that the fraction of hadronic events with a strange particle produced in events with forward mass MF agrees well with the same measurement in e+e− annihilation at a center-of-mass energy Ec.m.=MF. The x=2PMF distributions of these three particles in the forward-mass rest frame are compared with theoretical predictions.

1 data table

Table 1

No description provided.