Angelini, C.
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Study of anti-p p --> pi0 pi0 eta from 600-MeV/c to 1940-MeV/c.

The Crystal Barrel collaboration Anisovich, A.V. ; Nikonov, V.A. ; Sarantsev, A.V. ; et al.
Phys.Lett.B 452 (1999) 180-186, 1999.
Inspire Record 501657 DOI 10.17182/hepdata.28094

Antiproton-proton annihilation into π 0 π 0 η has been studied with incident beam momenta of 0.6 to 1.94 GeV/c. The main aim is to look for resonances formed by p ̄ p and decaying into π 0 π 0 η . Resonances observed are: two 4 ++ resonances with mass and width (M, Γ ) at (2044, 208) MeV and (2320±30, 220±30) MeV; three 2 ++ resonances at (2020±50, 220±70) MeV, (2240±40, 170±50) MeV and (2370±50, 320±50) MeV; two 3 ++ resonances at (2000±40, 250±40) MeV and (2280±30, 210±30) MeV; a 1 ++ resonance at (2340±40, 340±40) MeV; and two 2 −+ resonances at (2040±40, 190±40) MeV and (2300±40, 270±40) MeV.

1 data table
Table 1

No description provided.


Evidence for a pi eta P-wave in anti-p p annihilations at rest into pi0 pi0 eta.

The Crystal Barrel collaboration Abele, A. ; Adomeit, J. ; Amsler, C. ; et al.
Phys.Lett.B 446 (1999) 349-355, 1999.
Inspire Record 498113 DOI 10.17182/hepdata.28121

A partial wave analysis is presented of two high-statistics data samples of protonium annihilation into π 0 π 0 η in liquid and 12 atm gaseous hydrogen. The contributions from the 1 S 0 , 3 P 1 and 3 P 2 initial atomic fine structure states to the two data sets are different. The change of their fractional contributions when going from liquid to gaseous H 2 as calculated in a cascade model is imposed in fitting the data. Thus the uncertainty in the fraction of S-state and P-state capture is minimized. Both data sets allow a description with a common set of resonances and resonance parameters. The inclusion of a π η P-wave in the fit gives supportive evidence for the ρ ̂ (1405) , with parameters compatible with previous findings.

1 data table
Table 1

No description provided.


Neutron production in coincidence with fragments from the 40Ca + H reaction at Elab = 357A and 565A MeV

Tuve, C. ; Albergo, S. ; Boemi, D. ; et al.
Phys.Rev.C 59 (1999) 233-238, 1999.
Inspire Record 493470 DOI 10.17182/hepdata.25641

Neutron production, in coincidence with fragments emitted in the 40Ca+H reaction at Elab=357A and 565A MeV, has been measured using a 3-module version of the multifunctional neutron spectrometer MUFFINS. The mean neutron multiplicities for neutrons detected in the angular range covered by MUFFINS (0°−3.2°) have been estimated from the comparison between the neutron cross sections, in coincidence with the fragments, and the elemental cross sections. We have found evidence for a preequilibrium emission of prompt neutrons in superposition to a “slower” deexcitation of the equilibrated remnant by emission of nucleons and fragments, as already seen in inclusive rapidity distributions. The energy dependence of the inclusive neutron production cross sections, measured in a previous work, is here interpreted as due to the stronger neutron focusing in the forward direction at the higher energy. Comparison with a BNV+phase space coalescence model is discussed.

1 data table
Table 1

No description provided.


Measurement of the proton and deuteron spin structure functions g2 and asymmetry A(2).

The E155 collaboration Anthony, P.L. ; Arnold, R.G. ; Averett, T. ; et al.
Phys.Lett.B 458 (1999) 529-535, 1999.
Inspire Record 493768 DOI 10.17182/hepdata.27072

We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 1.0 < Q^2 < 30(GeV/c)^2 by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets.The absolute value of A2 is significantly smaller than the sqrt{R} positivity limit over the measured range, while g2 is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d2p, d2d and d2n. The Burkhardt-Cottingham sum rule integral - int(g2(x)dx) is reported for the range 0.02 < x < 0.8.

4 data tables
Table 1

2.75 degree spectrometer data.

Table 2

5.5 degree spectrometer data.

Table 3

10.5 degree spectrometer data.

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Measurement of gamma p --> K0 Sigma+ at photon energies up to 1.55-GeV.

The SAPHIR collaboration Goers, S ; Barth, J ; Bennhold, C ; et al.
Phys.Lett.B 464 (1999) 331-338, 1999.
Inspire Record 512574 DOI 10.17182/hepdata.27045

The reaction γp → K 0 Σ + has been measured with the SAPHIR detector at the electron stretcher ring ELSA. The total cross section rises up to a peak value of 1.1 μ b at a photon energy of 1.4 GeV. The differential cross sections dσ/dΩ are consistent with being flat throughout the measured energy range. The first measurement of the Σ + polarization in photon induced reactions was obtained.

3 data tables
Table 1

Total cross section for the reaction GAMMA P --> K0 SIGMA+. Errors include statistics and the uncertainty on the acceptance calculation and photon flux.

Table 2

Differential cross section for the reaction GAMMA P --> K0 SIGMA+. Errors are dominated by statistical uncertainties.

Table 3

Measure of SIGMA+ polarization in the reaction GAMMA P --> K0 SIGMA+.


Measurement and interpretation of fermion pair production at LEP energies from 130-GeV to 172-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J.C 11 (1999) 383-407, 1999.
Inspire Record 495462 DOI 10.17182/hepdata.34520

None

9 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Virtual Compton scattering under pi0 threshold at Q**2 = 0.33-GeV**2: Preliminary results.

Roche, J. ; Bartsch, P. ; Berthot, J. ; et al.
Nucl.Phys.A 654 (1999) 547c-551c, 1999.
Inspire Record 500668 DOI 10.17182/hepdata.31223

We have measured the absolute unpolarized cross sections for photon electro-production off the proton ep → epγ with the Three-Spectrometer-Setup at MAMI at a momentum transfer q=600 MeV/c and a virtual photon polarization ɛ=0.62. The momentum q ′ of the outgoing real photon range from 33 to 111 MeV/c. We extracted two combinations of the recently introduced generalized polarizabilities [1,2].

1 data table
Table 1

No description provided.


Measurement of vector-tensor spin-transfer observables for the reaction H(p(pol.),d(pol.))pi+ between 580-MeV and 1300-MeV.

Furget, C ; Goy, J ; Kox, S ; et al.
Nucl.Phys.A 655 (1999) 495-521, 1999.
Inspire Record 512680 DOI 10.17182/hepdata.36156

The three polarization tensor components of the deuteron produced in the H( p , d )π + reaction have been measured for the first time. The experiment was performed using a vertically polarized proton beam produced by the SATURNE accelerator. The deuteron polarization was measured with the POLDER polarimeter. The three polarizing powers t 20 00 , t 21 00 and t 22 00 and the three spin-transfer observables t 20 11 , t 22 11 and t 22 11 have been extracted at a proton kinetic energy of 580 MeV over a wide angular range and at two fixed center-of-mass angles, 132° and 151°, between 800 and 1300 MeV. The six observables, calculated in the C.M. helicity frame, have been compared with predictions of the most refined partial-wave analyses and also with the predictions of a theoretical coupled-channel model which includes the NN-NΔ transition. The comparison between the data and the theory/partial-wave analyses shows some discrepancies which get worse with increasing proton energy. Adding these data to the world database should improve significantly future partial-wave analyses. The A y 0 analyzing power has also been measured over the same kinematical range. The partial-wave analysis predictions are in good agreement with this observable.

7 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Study of anti-n p --> phi pi+ and anti-n p --> omega pi+ annihilation reactions in flight.

The OBELIX collaboration Filippi, A. ; Agnello, M. ; Balestra, F. ; et al.
Nucl.Phys.A 655 (1999) 453-494, 1999.
Inspire Record 512679 DOI 10.17182/hepdata.36158

The results of a study of the annihilation reactions n p → θπ + and n p → ωπ + are reported; the data were collected by the OBELIX apparatus, with antineutrons annihilating in flight (momenta from ∼ 50 MeV/ c to 405 MeV/ c ). Annihilation frequencies and annihilation cross sections have been deduced, for both channels, as a function of antineutron momentum. From the cross section ratio, a substantial deviation from OZI rule expectations is observed. An s s quark content in the nucleon offers a fairly plausible explanation for such an effect.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Antinuclei production in heavy ion collisions at CERN SPS.

The NA52 collaboration Arsenescu, R. ; Baglin, C. ; Beck, H.P. ; et al.
Nucl.Phys.A 661 (1999) 177-184, 1999.
Inspire Record 514756 DOI 10.17182/hepdata.36135

Besides the dedicated search for strangelets NA52 measures light (anti)particle and (anti)nuclei production over a wide range of rapidity. Compared to previous runs the statistics has been increased in the 1998 run by more than one order of magnitude for negatively charged objects at different spectrometer rigidities. At a rigidity of −20 GeV/ c we measured 10 6 p , 10 3 d and one 3 He without any centrality requirements. These preliminary results together with previous measurements near central rapidity are discussed in the framework of a thermodynamical and a coalescence model.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.