Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ and $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV

The GlueX collaboration Al Ghoul, H. ; Anassontzis, E.G. ; Austregesilo, A. ; et al.
Phys.Rev.C 95 (2017) 042201, 2017.
Inspire Record 1511149 DOI 10.17182/hepdata.76745

We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\to p\pi^0$ and $\vec{\gamma}p\to p\eta $ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\pi^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

2 data tables

Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.

Measurement of the beam asymmetry $\Sigma$ for $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.


Asymmetry of the cross section of the reaction $\gamma$P $\rightarrow$ P$\pi^{0}$ in the energy interval 0.9-1.65 GeV at $\theta _{\pi}^{0 cms}$ = 110°

Abramyan, L.O. ; Avakyan, R.O. ; Akopov, N.Z. ; et al.
JETP Lett. 23 (1976) 375-378, 1976.
Inspire Record 1393126 DOI 10.17182/hepdata.39803

None

2 data tables

THE ERRORS INCLUDE THE 10 PCT ERROR IN THE EFFECTIVE PHOTON POLARIZATION.

No description provided.


A precise measurement of the tau polarisation at LEP-1.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J.C 14 (2000) 585-611, 2000.
Inspire Record 511443 DOI 10.17182/hepdata.49001

The$\tau$polarisation has been studied with the${\rm e^+e^-}\to \tau^+\tau^-$data collected by the DELPHI detector at LEP in

2 data tables

The errors are statistical and systematic combined in quadrature.

No description provided.


Analyzing powers and partial wave decomposition of p n --> p p((1)S(0)) pi- at low energies.

Hahn, H. ; Duncan, F.A. ; Aclander, J. ; et al.
Phys.Rev.Lett. 82 (1999) 2258-2261, 1999.
Inspire Record 500174 DOI 10.17182/hepdata.19495

Analyzing powers for p→n→pp(S01)π− were measured at beam energies 353, 404, and 440 MeV by extracting the quasifree process from p→d→pppπ−. Partial wave amplitude analysis yields a significant contribution from the isospin 1, s-wave channel. This contribution is relatively much larger than that expected from theoretical models which have been successful in describing the isospin 1, s-wave channel behavior of pp→ppπ0 cross sections at threshold.

3 data tables

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

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

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


A-dependence of Polarization of $\Lambda^0$ Produced Inclusively in Neutron - Nucleus Interactions

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.
Z.Phys.C 36 (1987) 27, 1987.
Inspire Record 237043 DOI 10.17182/hepdata.39599

TheA-dependence of the polarization ofΛ0,s produced inclusively in neutron-nucleus interactions at a mean neutron momentum of about 40 GeV/c has been measured in an experiment performed using the BIS-2 spectrometer at the Serpukhov accelerator. Carbon, Aluminium and Copper targets were used. TheΛ0,s were produced in the kinematical region of 0.6<pT<1.3 GeV/c and 0.2<xF<0.9. Describing the polarization of theΛ0,s by ℘=a·A a value of (−0.15+0.07/−0.60) was obtained by a fit to our data.

2 data tables

POLARIZATION IS DESCRIBED BY A POWER LOW: POL = C*A**B, WHERE C = -1.1, +0.4, -0.3 , A- ATOMIC NUMBER AND B = -0.15, +0.07, -0.6.


POLARIZATION PARAMETERS SIGMA, T, AND P FOR THE REACTION GAMMA P ---> P PI0 IN THE ENERGY INTERVAL 0.9-GEV - 1.5-GEV AT THETA (PI0) center-of-mass = 120-DEGREES

Asaturian, M.M. ; Belyaev, A.A. ; Vartapetian, G.A. ; et al.
JETP Lett. 44 (1986) 341-344, 1986.
Inspire Record 240634 DOI 10.17182/hepdata.16911

None

1 data table

No description provided.


Polarization of Charmed $\Lambda(c$)+ Baryons Produced in Neutron - Carbon Interactions

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.
Yad.Fiz. 43 (1986) 619-623, 1986.
Inspire Record 209855 DOI 10.17182/hepdata.39660

None

3 data tables

No description provided.

No description provided.

No description provided.


CROSS-SECTION ASYMMETRY OF THE gamma n ---> pi- p REACTION BY POLARIZED PHOTONS IN THE THIRD AND FOURTH RESONANCE REGIONS

Adamian, F.V. ; Akopian, G.G. ; Galumian, P.I. ; et al.
EFI-722-37-84-YEREVAN, 1984.
Inspire Record 206944 DOI 10.17182/hepdata.18433

None

5 data tables

No description provided.

No description provided.

No description provided.

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ASYMMETRY OF THE REACTION CROSS-SECTION FOR PI+ MESON PHOTOPRODUCTION ON HYDROGEN INDUCED BY POLARIZED PHOTONS IN THE RESONANCE ENERGY REGION. (IN RUSSIAN)

Abramian, L.O. ; Aganyants, Aleksandr O. ; Adamian, F.V. ; et al.
Yad.Fiz. 32 (1980) 128-132, 1980.
Inspire Record 159785 DOI 10.17182/hepdata.18977

None

2 data tables

Axis error includes +- 10/10 contribution (DUE TO BEAM POLARIZATION UNCERTAINTY).

Axis error includes +- 10/10 contribution (DUE TO BEAM POLARIZATION UNCERTAINTY).


Cross-Section Asymmetry of eta Mesons Photoproduction by Polarized Photons in the Resonance Region

Abramian, L.O. ; Avakian, R.O. ; Aganyants, Aleksandr O. ; et al.
Pisma Zh.Eksp.Teor.Fiz. 25 (1977) 597-600, 1977.
Inspire Record 124683 DOI 10.17182/hepdata.39787

None

1 data table

No description provided.