Criegee, L.
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A measurement of the QCD colour factors and a limit on the light gluino.

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.
Z.Phys.C 76 (1997) 1-14, 1997.
Inspire Record 440051 DOI 10.17182/hepdata.34162

Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios CA/CF and TF /CF and the strong coupling constant αs = CFαs(MZ)/(2π) has been performed by fitting theoretical predictions simultaneously to the measured differential two-jet rate and angular distributions in four-jet events. The result is found to be in excellent agreement with QCD, {fx4-1} Fixing CA/CF and TF/CF to the QCD values permits a determination of αs(MZ) and ηf, the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c2 is excluded at 95% confidence level.

3 data tables
Table 1

Fit A: using all kinematical distributions. NC, CF, and TF are the color factors for SU(3) group, NF is the number of the active flavors.

Table 2

Fit B: using all kinematical distributions, but QCD magnitudes for color factors are used: FA(DEF=NC/CF)) = 2.25 and TF/CF = 0.375. NC, CF, and TF are the color factors for SU(3) group, NF is the number of the active flavors.

Table 3

Fit C: the QCD magnitudes for color factors and NF = 5 are used.


Spin asymmetries from O-16(gamma(pol.),p pi-) near Delta resonance energies

Hicks, K. ; Baghaei, H. ; Caracappa, A. ; et al.
Phys.Rev.C 55 (1997) R12-R15, 1997.
Inspire Record 456890 DOI 10.17182/hepdata.25766

Spin asymmetries for the 16O(γ→,pπ−) reaction are reported for incident photon energies of 293 ± 20 MeV, proton angles ranging from 28° to 140° (lab), and pion angles of 35° to 115°. The data are compared with calculations in a quasifree plane-wave impulse approximation model. This model is in good agreement with the data at small momentum transfer q, but does not follow the trend of the data at large q. Sensitivity to the Δ-nucleus potential and to modification of the Δ lifetime from nuclear medium effects are explored using a simple modification of the Δ propagator in the calculations.

6 data tables
Table 1

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

Table 2

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

Table 3

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

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Study of anti-neutron proton annihilation in two mesons in the momentum range between 50 to 400 MeV/c with OBELIX

The OBELIX collaboration Bertin, A. ; Bruschi, M. ; Capponi, M. ; et al.
Phys.Lett.B 410 (1997) 344-352, 1997.
Inspire Record 459313 DOI 10.17182/hepdata.28243

We measured the in flight annihilation frequencies and cross sections of reactions n p → π + π 0 ,π + η and K + K S in the antineutron momentum range between 50 and 400 MeV/c. The annihilation frequencies of these channels from the different allowed initial states were calculated and some information about the n p annihilation dynamics were obtained. The first determination of the D-wave contribution in this momentum range was also obtained.

1 data table
Table 1

No description provided.


Charged particle production in S S collisions at 200-GeV/c per nucleon

The WA94 collaboration Andrighetto, A. ; Antinori, F. ; Bayes, A.C. ; et al.
Phys.Lett.B 412 (1997) 148-154, 1997.
Inspire Record 460283 DOI 10.17182/hepdata.28242

Charged particle production in central S-S collisions at 200 GeV/ c per nucleon has been studied by the WA94 experiment at the CERN-SPS. Particle identification has been provided by the Omega RICH, while a silicon telescope in the Omega spectrometer and an array of MultiWire Proportional Chambers have been used to trace particles through the RICH detector. Production ratios and transverse mass spectra for π ± , K ± and p( p ) at central rapidity and p T > 1.3 GeV/ c are presented.

3 data tables
Table 1

Distributions are fitted with (1/MT**1.5)*DSIG/DMT = CONST*EXP(-MT/SLOPE).

Table 2

1.54 GeV ratio is calculated from the fit to the MT distribution.

Table 3

1.54 GeV ratio is calculated from the fit to the MT distribution.


Anomalous J / psi suppression in Pb - Pb interactions at 158 GeV/c per nucleon

The NA50 collaboration Abreu, M.C. ; Alessandro, B. ; Alexa, C. ; et al.
Phys.Lett.B 410 (1997) 337-343, 1997.
Inspire Record 459314 DOI 10.17182/hepdata.28260

The Drell-Yan and J ψ cross-sections measured in PbPb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J ψ in PbPb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions.

2 data tables
Table 1

The results from other experiments are also presented.

Table 2

Different data are rescaled at 200 GeV.


Study of the pi0 pi0 eta-prime final state in anti-p p annihilation at rest

The Crystal Barrel collaboration Abele, A. ; Adomeit, J. ; Amsler, C. ; et al.
Phys.Lett.B 404 (1997) 179-186, 1997.
Inspire Record 457856 DOI 10.17182/hepdata.28292

A partial wave analysis of p̄p → π 0 π 0 η ′ has been performed using the η′ → π 0 π 0 η and η ′ → γγ decay modes. The data are dominated by an η ′ recoiling against the ( ππ ) S-wave. In addition, α 2 (1320) → η′π 0 is needed. There is evidence for contributions from α 0 (1450) → η′π 0 . The branching ratio of α 0 (1450) → η′π 0 with respect to ηπ 0 is consistent with the prediction of SU(3).

1 data table
Table 1

No description provided.


Tensor analyzing power T(20) in backward elastic d p scattering and breakup at 0-degrees between 3.5-GeV/c and 6.5-GeV/c

Azhgirey, L.S. ; Chernykh, E.V. ; Kobushkin, A.P. ; et al.
Phys.Lett.B 391 (1997) 22-28, 1997.
Inspire Record 456818 DOI 10.17182/hepdata.28323

The tensor analyzing power T 20 for the p ( d , p d) and p ( d , p ) pn reactions θ cm p = 180° have been measured at incident deuteron momenta from 3.5 to 6.5 GeV/ c . For both reactions T 20 remains negative up to internal momentum k ⋍ 0.85 GeV/ c and show a rich structure beyond the region where T 20 is expected to be determined by the S - and D -states of the deuteron. The T 20 data for deuteron breakup without pion production, close to the backward elastic kinematics, were obtained simultaneously with the elastic data.

1 data table
Table 1

K is the internal momentum of the nucleon.


Threshold measurements at the internal experimental facility COSY-11

Balewski, J. ; Brauksiepe, S. ; Budzanowski, A. ; et al.
Nucl.Phys.A 626 (1997) 85C-92C, 1997.
Inspire Record 463151 DOI 10.17182/hepdata.36361

The experimental setup and detection technique of the COSY-11 installation, an internal experimental facility at the cooler synchrotron and storage ring COSY Jülich, are described. The detection system has been designed for meson production studies with full geometrical acceptance close to threshold. Preliminary results of first measurements are presented, emphasis is put on strangeness production in the reactions pp → ppK + K − and pp → pK + Λ .

2 data tables
Table 1

Excess energy of 6.1 MeV above threshold 3.3016 GeV.

Table 2

Excess energy of 2 MeV above threshold 2.339 GeV.


Measurement of the quasifree p + n --> d + eta reaction near threshold.

Calen, H. ; Dyring, J. ; Fransson, K. ; et al.
Phys.Rev.Lett. 79 (1997) 2642-2645, 1997.
Inspire Record 450604 DOI 10.17182/hepdata.19551

The quasifree p+n→d+η reaction cross section has been measured in the near-threshold region using deuterium from an internal cluster-jet target and 1350 MeV protons in the CELSIUS storage ring of the The Svedberg Laboratory, Uppsala. The energy dependence of the cross section is extracted by exploiting the Fermi momentum of the target neutron and reconstructing the kinematics on an event-by-event basis. The data cover center of mass excess energies from 16 to 113 MeV.

1 data table
Table 1

No description provided.


J / psi and Drell-Yan cross-sections in Pb Pb interactions at 158 GeV/c per nucleon

The NA50 collaboration Abreu, M.C. ; Alessandro, B. ; Alexa, C. ; et al.
Phys.Lett.B 410 (1997) 327-336, 1997.
Inspire Record 459315 DOI 10.17182/hepdata.5631

First results are reported on J ψ and Drell-Yan cross-sections in PbPb reactions at 158 GeV/ c per nucleon. The ratio of cross-sections σ J/ψ /σ DY is studied as a function of the impact parameter of the collision estimated from the measured transverse energy.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

The Drell-Yan cross sections are taken in the mass interval 2.9 to 4.5 GeV. SIG/SIG ratio are free from most systematic errors.

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