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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REACTION OF QUASIELASTIC CHARGE EXCHANGE P HE-3 ---> N(F) P P P AT MEDIUM-ENERGIES. (IN RUSSIAN)

Blinov, A.V. ; Vanyushin, I.A. ; Grechko, V.E. ; et al.
Sov.J.Nucl.Phys. 47 (1988) 594, 1988.
Inspire Record 253277 DOI 10.17182/hepdata.9993

None

8 data tables

N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=3), WHERE PMIN IS DETERMINED FROM ALL EVENTS.

N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=4,5,6), WHERE PMIN IS DETERMINED FROM ALL EVENTS.

No description provided.

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STUDY OF DIFFERENTIAL CROSS-SECTIONS FOR THE REACTIONS H-3 (P, N) HE-3 AND H-3 (P, P) H-3 AT THE TRITON MOMENTUM OF 2.5-GEV/C. (IN RUSSIAN)

Blinov, A.V. ; Vanyushin, I.A. ; Voitenko, I.D. ; et al.
Yad.Fiz. 35 (1982) 523-531, 1982.
Inspire Record 179833 DOI 10.17182/hepdata.2691

None

3 data tables

No description provided.

No description provided.

No description provided.


Photoproduction of $\omega$ mesons off protons and neutrons

The CBELSA/TAPS collaboration Dietz, F. ; Metag, V. ; Anisovich, A.V. ; et al.
Eur.Phys.J.A 51 (2015) 6, 2015.
Inspire Record 1340913 DOI 10.17182/hepdata.69767

ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π$^{0}$ γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ≈ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E$_{γ}$ < 1.6 GeV. For higher incident beam energies this factor goes down to ≈ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements.

85 data tables

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.125-1.150 GeV.

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.150-1.175 GeV.

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.175-1.200 GeV.

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SMALL ANGLE ELASTIC P HE-4 SCATTERING AT THE ENERGY OF 992-MEV (IN RUSSIAN)

Velichko, G.N. ; Vorobev, A.A. ; Zalite, Yu.K. ; et al.
Sov.J.Nucl.Phys. 35 (1982) 154-157, 1982.
Inspire Record 179835 DOI 10.17182/hepdata.38070

None

3 data tables

DATA IS DEPEND OF MODEL.

DATA IS DEPEND OF MODEL.


Charge Exchange $K^- p$ Scattering in the Range of Small T at 30-{GeV}/$c$ Momentum

The Serpukhov-Brussels-Annecy(LAPP) & Serpukhov-CERN collaborations Binon, F.G. ; Gouanere, M. ; Davydov, V.A. ; et al.
Sov.J.Nucl.Phys. 33 (1981) 542, 1981.
Inspire Record 156875 DOI 10.17182/hepdata.41422

None

3 data tables

D(SIG)/D(T) AT T=0. OBTAINED FROM MODEL EXTRAPOLATION OF PRESENTED T DEPENDENCE OF D(SIG)/D(T).


$\pi^- p$ Scattering With Charge Exchange in the Region of Small T at 40-{GeV}/$c$ Momentum

The Serpukhov-Brussels-Annecy(LAPP) & Serpukhov-CERN collaborations Binon, F.G. ; Gouanere, M. ; Davydov, V.A. ; et al.
Sov.J.Nucl.Phys. 33 (1981) 663, 1981.
Inspire Record 156874 DOI 10.17182/hepdata.41613

None

2 data tables

D(SIG)/D(T) AT T=0. OBTAINED FROM MODEL EXTRAPOLATION.


Reaction $\pi^- p \to \omega n$ in the 15-{GeV}/$c$ - 40-{GeV}/$c$ Momentum Range

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Krüger, M. ; et al.
Lett.Nuovo Cim. 25 (1979) 493, 1979.
Inspire Record 142561 DOI 10.17182/hepdata.37383

None

7 data tables

DATA OBTAINED IN ASSUMPTION THAT RHO(MM=00,P=3,XYZ=SH)=1-2*RHO(MM=1-1,P=3,XYZ=SH).

INTEGRATED CROSS SECTION, INCLUDING SYSTEMATIC UNCERTAINTY IN ERRORS Axis error includes +- 15/15 contribution (DECAY-BR(BRN=OMEGA --> PI0 GAMMA,BR=0.088 +- 0.005)).

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Reaction $\pi^- p \to \eta^\prime n$ in the 15-{GeV}/$c$ - 40-{GeV}/$c$ Momentum Range

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Bertolucci, E. ; et al.
Phys.Lett.B 83 (1979) 131, 1979.
Inspire Record 141023 DOI 10.17182/hepdata.49657

Measurements were made of the cross section of the reactions π − p → ν ′(958)n, η ′ → 2 γ at momenta at 15, 20, 25, 30 and 40 GeV/c. The experiment was carried out on the IHEP 70 GeV accelerator using the 648 channel hodoscope spectrometer NICE for γ-ray detection. A total of 6000 η′ mesons were recorded. A sharp drop is seen in the differential cross section for t → 0. The dependences of the differential cross sections for the π − p → η ′n and π − p → η n on t are identical. On the basis of the ratio of the cross sections for these reactions at t = 0, i.e. R( η′ n ) t=0 = 0.55 ± 0.06 , the singlet-octet mixing angle for pseudoscalar mesons was determined to be β = −(18.2 ± 1.4)°.

8 data tables

AVERAGE RATIO IS 2.76 +- 0.07 PCT.

AVERAGE RATIO IS 0.52 +- 0.02.

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Reaction $\pi^- p \to \pi^0 n$ in the 15-{GeV}/$c$ - 40-{GeV}/$c$ Momentum Range

The Serpukhov-CERN collaboration Apel, W.D. ; Augenstein, K.H. ; Bertolucci, E. ; et al.
Nucl.Phys.B 154 (1979) 189, 1979.
Inspire Record 140776 DOI 10.17182/hepdata.34746

A high statistics measurement of the reaction π − p → π 0 n has been performed at the Serpukhov accelerator for 15, 20, 25, 30 and 40 GeV/ c incident pion momentum using the NICE set-up with its associated 648-channel hodoscope spectrometer for γ-ray detection. More than 3 million charge-exchange events have been recorded in total. It is found that the spin-flip and non-spin-flip amplitudes can be parametrized, for small | t |, as exponentials with the same slopes to within a few percent. Also the behaviour of the differential cross section for small and medium | t | agrees with the prediction of a geometrical s -channel model which describes binary reactions in terms of a complex pole b 0 ( s ). The imaginary part of this universal pole, Im b 0 ( s ), has been determined and found to be growing logarithmically with s .

1 data table

No data in this table.