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Invariant mass distributions for the pp ---> pp eta reaction at Q = 10 MeV

Moskal, P. ; Czyzykiewicz, R. ; Czerwinski, E. ; et al.
Eur.Phys.J. A43 (2010) 131-136, 2010.
Inspire Record 839339 DOI 10.17182/hepdata.54192

Proton-proton and proton-eta invariant mass distributions and the total cross section for the pp to pp eta reaction have been determined near the threshold at an excess energy of Q=10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q=15.5 MeV and Q= 40MeV.

3 data tables

Total cross section determined from the integral of the invariant mass distribution.

Distribution of the square of the invariant mass of the proton-proton system.

Distribution of the square of the invariant mass of the proton-eta system.


Mechanism of the close-to-threshold production of the eta meson

Czyzykiewicz, R. ; Moskal, P. ; Adam, H.-H. ; et al.
Phys.Rev.Lett. 98 (2007) 122003, 2007.
Inspire Record 731185 DOI 10.17182/hepdata.41775

Measurements of the analysing power for the p(pol)p --> ppeta reaction have been performed in the close-to-threshold energy region at beam momenta of p_{beam}=2.010 and 2.085 GeV/c, corresponding to excess energies of Q=10 and 36 MeV, respectively. The determined analysing power is essentially consistent with zero implying that the eta meson is produced predominantly in the s-wave at both excess energies. The angular dependence of the analysing power, combined with the hitherto determined isospin dependence of the total cross section for the eta meson production in nucleon-nucleon collisions, reveal a statistically significant indication that the excitation of the nucleon to the S_{11}(1535) resonance, the process which intermediates the production of the eta meson, is predominantly due to the exchange of the pi meson between the colliding nucleons.

2 data tables

Analysing power measurements for excess energy 10 MeV.

Analysing power measurements for excess energy 36 MeV.


Exclusive eta production in proton-proton reactions

Balestra, F. ; Bedfer, Y. ; Bertini, R. ; et al.
Phys.Rev. C69 (2004) 064003, 2004.
Inspire Record 653991 DOI 10.17182/hepdata.25225
8 data tables

Differential cross section for incident kinetic energy 2.15 GeV, divided by the phase space as a function of the invariant mass of the ETA and the final state proton with the lower value of ABS(T). This is proportional to the square of the decay matrix element ABS(M)**2 of the P-ETA system.

Differential cross section for incident kinetic energy 2.50 GeV, divided by the phase space as a function of the invariant mass of the ETA and the final state proton with the lower value of ABS(T). This is proportional to the square of the decay matrix element ABS(M)**2 of the P-ETA system.

Differential cross section for incident kinetic energy 2.85 GeV, divided by the phase space as a function of the invariant mass of the ETA and the final state proton with the lower value of ABS(T). This is proportional to the square of the decay matrix element ABS(M)**2 of the P-ETA system.

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Analyzing power A(y) in the reaction polarized-p p ---> p p eta close to threshold

Winter, P. ; Adam, H.H. ; Bauer, F. ; et al.
Phys.Lett. B544 (2002) 251-258, 2002.
Inspire Record 599591 DOI 10.17182/hepdata.31686

Measurements of the eta meson production with a polarised proton beam in the reaction p(pol) p --> p p eta have been carried out at an excess energy of Q = 40 MeV. The dependence of the analysing power A_y on the polar angle theta^*_q of the eta meson in the center of mass system (CMS) has been studied. The data indicate the possibility of an influence of p- and d-waves to the close to threshold eta production.

1 data table

Averaged value of the analyzing power and cross section as a function of the emmission angle of the ETA meson is the CM system.


Measurement of the eta production in proton proton collisions with the COSY time-of-flight spectrometer

The COSY-TOF collaboration Abdel-Bary, M. ; Abdel-Samad, S. ; Bilger, R. ; et al.
Eur.Phys.J. A16 (2003) 127-137, 2003.
Inspire Record 587236 DOI 10.17182/hepdata.43626

The reaction pp -> pp eta was measured at excess energies of 15 and 41 MeV at an external target of the Juelich Cooler Synchrotron COSY with the Time of Flight Spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of the process pp eta were detected with an acceptance of nearly 100% and the eta was reconstructed by the missing mass technique. For both excess energies the angular distributions are found to be nearly isotropic. In the invariant mass distributions strong deviations from the pure phase space distributions are seen.

6 data tables

Angular distribution of the ETA in the CM frame.

Angular distribution of the P P momentum in the CM frame.

Squared P P invariant mass distribution.

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Production of eta-prime mesons in the p p ---> p p eta-prime reaction at 3.67-GeV/c

The DISTO collaboration Balestra, F. ; Bedfer, Y. ; Bertini, R. ; et al.
Phys.Lett. B491 (2000) 29-35, 2000.
Inspire Record 532685 DOI 10.17182/hepdata.31445

The ratio of the total exclusive production cross sections for $\eta\prime$ and $\eta$ mesons has been measured in the $pp$ reaction at $p_{beam}=3.67$ GeV/c. The observed $\eta\prime/\eta$ ratio is $(0.83\pm{0.11}^{+0.23}_{-0.18})\times 10^{-2}$ from which the exclusive $\eta\prime$ meson production cross section is determined to be $(1.12\pm{0.15}^{+0.42}_{-0.31})\mu b$. Differential cross section distributions have been measured. Their shape is consistent with isotropic $\eta\prime$ meson production.

5 data tables

No description provided.

No description provided.

Only statistial errors.

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Comparison of eta and eta-prime production in the p p ---> p p eta (eta-prime) reactions near threshold

Hibou, F. ; Bing, O. ; Boivin, M. ; et al.
Phys.Lett. B438 (1998) 41-46, 1998.
Inspire Record 466930 DOI 10.17182/hepdata.28154

The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model.

2 data tables

Axis error includes +- 10/10 contribution (Overall normalization error already included).

Axis error includes +- 10/10 contribution (Overall normalization error already included).


Near threshold eta meson production in proton proton collisions

Smyrski, J. ; Wuestner, P. ; Budzanowski, A. ; et al.
Phys.Lett. B474 (2000) 182-187, 2000.
Inspire Record 512406 DOI 10.17182/hepdata.28056

The production of eta mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies in the range from 0.5 MeV to 5.4 MeV. The energy dependence of the total cross section is well described by the available phase-space volume weighted by FSI factors for the proton-proton and proton-eta pairs.

1 data table

The total cross sections as a function of beam momentum and excess energy with statistical errors. The uncertainty on the beam momentum and excess energy are +- 0.00080 GeV and +- 0.28 MeV respectively.


The p p ---> p p eta reaction near the kinematical threshold

Calen, H. ; Carius, S. ; Fransson, K. ; et al.
Phys.Lett. B366 (1996) 39-43, 1996.
Inspire Record 427397 DOI 10.17182/hepdata.28423
1 data table

No description provided.


eta meson production in p d and p p collisions

Chiavassa, E. ; Dellacasa, G. ; De Marco, N. ; et al.
Phys.Lett. B337 (1994) 192-195, 1994.
Inspire Record 384615 DOI 10.17182/hepdata.28780
8 data tables

No description provided.

No description provided.

No description provided.

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Measurement of the p p ---> p p eta total cross-section between 1.265-GeV and 1.5-GeV

Chiavassa, E. ; Dellacasa, G. ; De Marco, N. ; et al.
Phys.Lett. B322 (1994) 270-274, 1994.
Inspire Record 376677 DOI 10.17182/hepdata.28768
1 data table

Value given at 1263 MeV assumes energy 2 MeV lower than nominal value. This uncertainty only affects this lowest energy point.


Total cross-section of the p p ---> p p eta reaction near threshold

Bergdolt, A.M. ; Bergdolt, G. ; Bing, O. ; et al.
Phys.Rev. D48 (1993) R2969-R2973, 1993.
Inspire Record 364575 DOI 10.17182/hepdata.22579
1 data table

No description provided.


Experimental study of four-prong events in proton proton interactions at 13.1 gev/c

Le Guyader, J. ; Sene, M. ; Ginestet, J. ; et al.
Nucl.Phys. B35 (1971) 573-591, 1971.
Inspire Record 75410 DOI 10.17182/hepdata.33033
2 data tables

NORMALIZED TO A TOTAL CROSS SECTION OF 39.6 +- 0.2 MB.

RESONANCE PRODUCTION ESTIMATED BY CUTS WITH MONTE-CARLO AND HAND-DRAWN PHASE SPACE DISTRIBUTIONS.


MAIN CHARACTERISTICS OF REACTIONS P P ---> P P PI+ PI- PI0 AND P P ---> P N PI+ PI+ PI- AT 4-GEV/. (IN RUSSIAN)

Beketov, G.V. ; Vanyushin, I.A. ; Ergakov, V.A. ; et al.
Yad.Fiz. 32 (1980) 1319-1328, 1980.
Inspire Record 159802 DOI 10.17182/hepdata.18033
25 data tables

No description provided.

No description provided.

No description provided.

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