Coherent diffractive photoproduction of $\rho^{0}$ mesons on gold nuclei at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 96 (2017) 054904, 2017.
Inspire Record 1515028 DOI 10.17182/hepdata.101354

The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly-real photon emitted by one ion scatters from the other ion. We fit the $\pi^+\pi^-$ invariant mass spectrum with a combination of $\rho$ and $\omega$ resonances and a direct $\pi^+\pi^-$ continuum. This is the first observation of the $\omega$ in ultra-peripheral collisions, and the first measurement of $\rho-\omega$ interference at energies where photoproduction is dominated by Pomeron exchange. The $\omega$ amplitude is consistent with the measured $\gamma p\rightarrow \omega p$ cross section, a classical Glauber calculation and the $\omega\rightarrow\pi^+\pi^-$ branching ratio. The $\omega$ phase angle is similar to that observed at much lower energies, showing that the $\rho-\omega$ phase difference does not depend significantly on photon energy. The $\rho^0$ differential cross section $d\sigma/dt$ exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with 2 minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

13 data tables

The $\pi^+\pi^-$ invariant-mass distribution for all selected $\pi\pi$ candidates with $p_T~<~100~\textrm{MeV}/c$.

The ratio $|B/A|$ of amplitudes of nonresonant $\pi^+\pi^-$ and $\rho^0$ mesons in the present STAR analysis.

The ratio $|B/A|$ of amplitudes of nonresonant $\pi^+\pi^-$ and $\rho^0$ mesons in the previous STAR analysis, Phys. Rev. C 77 034910 (2008).

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Study on the cross section asymmetry of deuteron photodisintegration induced by low energy polarized γ quanta

Barannik, V.P. ; Gorbenko, V.G. ; Gushchin, V.A. ; et al.
Yad.Fiz. 38 (1983) 1108-1100, 1983.
Inspire Record 1408810 DOI 10.17182/hepdata.17732

Results are presented on measured asymmetry parameter in the cross sections of the deuteron photodesintegration by linearly polarized photon beam in the energy range 40-70 MeV for the proton emission angles of 75 and 90 deg in the c. m. s. The experimental data are compared with the theoretical calculations by Partovi, Arenhovel, as well as with calculations performed within an invariant approach with gauge-invariant amplitudes in the pole approximation. The results of the calculation by Arenhovel and the present calculations satisfactorily agree with the experimental data, while the Partovi theory does not describe the asymmetry parameter measurements for photon energies above 40 MeV

1 data table

No description provided.


THE ASYMMETRY SIGMA HAS BEEN DETERMINED BY THE FORMULA: D(SIG)/D(OMEGA)=D(SIG0)/D(OMEGA)*(1+P*SIGMA*COS(PHI)), WHERE D(SIG0)/D(OMEGA) - CROSS SECTION ON U NPOLARIZED PHOTON BEAM, P - BEAM POLARIZATION, PHI - ASIMUTHAL ANGLE BETWEEN POLARIZATION VECTOR OF BEAM AND THE PLANE OF THE REACTION.


Polarization of protons in the reactions $\gamma^{3,4}$He$\rightarrow\overrightarrow{p}X$ and the quasideuteron model

Zybalov, A.A. ; Karasev, S.P. ; Konovalov, O.G. ; et al.
Sov.J.Nucl.Phys. 47 (1988) 955-956, 1988.
Inspire Record 1392524 DOI 10.17182/hepdata.17410

None

1 data table

No description provided.


Cross-section asymmetry in two-particle photodisintegration of helium-3 by linearly polarized protons

Belyaev, A.A. ; Ganenko, V.B. ; Get'man, V.A. ; et al.
Sov.J.Nucl.Phys. 44 (1986) 181-183, 1986.
Inspire Record 1392511 DOI 10.17182/hepdata.17441

None

2 data tables

No description provided.

No description provided.


Photofission of Bi, Pb, Au, Pt, Os, Re, Ta, and Hf below 260 MeV

Ranyuk, Yu.N. ; Sorokin, P.V. ;
Sov.J.Nucl.Phys. 5 (1967) 26-29, 1967.
Inspire Record 1392566 DOI 10.17182/hepdata.17313

None

2 data tables

No description provided.

No description provided.


Proton polarization in deuteron photodisintegration in the Δ(1232)-resonance region

Zybalov, A.A. ; Konovalov, O.G. ; Marekhin, S.V. ; et al.
Nucl.Phys.A 533 (1991) 642-650, 1991.
Inspire Record 1392876 DOI 10.17182/hepdata.36724

We report the results from measurements of proton polarization P , in the γ +D→p+n reaction at photon energies ranging from 200 to 350 MeV. The data obtained are compared with the measured analysing power A , of the reverse reaction and with model calculations. The assumption of the dominant contribution of isobar configurations in this region is on the whole confirmed by the present proton polarization measurements.

5 data tables

No description provided.

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Angular dependence of the asymmetry of the cross section for the reaction $\gamma$p $\rightarrow$ $\Delta^{++}\pi^{-}$ at a photon energy 650 MeV

Ganenko, V.B. ; Gorbenko, V.B. ; Zhebrovskii, Yu.V. ; et al.
JETP Lett. 16 (1972) 310-312, 1972.
Inspire Record 1393130 DOI 10.17182/hepdata.39786

None

1 data table

No description provided.


Asymmetry of the cross section of gamma d ---> pi0 d reaction at photon energy of 350 mev

Ganenko, V.B. ; Gorbenko, V.G. ; Zhebrovskii, Yu.V. ; et al.
Pisma Zh.Eksp.Teor.Fiz. 18 (1973) 483-486, 1973.
Inspire Record 87826 DOI 10.17182/hepdata.39926

None

1 data table

No description provided.


Eta photoproduction on the proton for photon energies from 0.75-GeV to 1.95-GeV

The CLAS collaboration Dugger, M. ; Ritchie, B.G. ; Ball, J. ; et al.
Phys.Rev.Lett. 89 (2002) 222002, 2002.
Inspire Record 603904 DOI 10.17182/hepdata.19406

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W=1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S11 resonance with mass ∼1.8  GeV couples to the ηN channel.

6 data tables

Cross sections for photon energies 0.775 to 0.925 GeV.

Cross sections for photon energies 0.975 to 1.125 GeV.

Cross sections for photon energies 1.175 to 1.325 GeV.

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