Bartke, J.
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A Study of $K^0_S$, $\Lambda$ and $\bar{\Lambda}$ Production in 60-{GeV} and 200-{GeV} Per Nucleon O Au and $p$ Au Collisions With a Streamer Chamber Detector at the {CERN} {SPS}

The NA35 collaboration Bamberger, A. ; Bartke, J. ; Bialkowska, H. ; et al.
Z.Phys.C 43 (1989) 25, 1989.
Inspire Record 276686 DOI 10.17182/hepdata.15456

The production of neutral strange particlesKso, Λ and\(\bar \Lambda \) has been studied in 60 and 200 GeV per nucleon OAu and pAu collisions with the streamer chamber vertex spectrometer of the NA35 experiment at the CERN-SPS accelerator. Ratios of neutral strange particle production to negatively charged particle production in selected regions of phase space were measured to be the same in OAu and pAu reactions. The rates of strange particle production in central OAu collisions are about a factor of 16 higher than in pAu collisions when compared in the same regions of phase space. If an enhancement of strange particle production in OAu collisions relative to pAu collisions is considered to be a signature for quark-gluon plasma formation, no evidence supporting it is observed. The experimental results are compared to the Lund FRITIOF model.

22 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Experimental Evidence for the Nonabelian Nature of {QCD}

The AMY collaboration Park, I.H. ; Schnetzer, S. ; Green, J. ; et al.
Phys.Rev.Lett. 62 (1989) 1713, 1989.
Inspire Record 276619 DOI 10.17182/hepdata.20045

We present evidence for the non-Abelian nature of QCD from a study of multijet events produced in e+e− annihilations from √s =50 to 57 GeV in the AMY detector at the KEK storage ring TRISTAN. A comparison of the three-jet event fraction at TRISTAN to the fraction of the DESY storage ring PETRA shows that the QCD coupling strength αs decreases with increasing Q2. In addition, measurements of the angular distributions of four-jet events show evidence for the triple-gluon vertex.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Charm photoproduction

The Tagged Photon Spectrometer collaboration Anjos, J.C. ; Appel, J.A. ; Bean, A. ; et al.
Phys.Rev.Lett. 62 (1989) 513-516, 1989.
Inspire Record 289318 DOI 10.17182/hepdata.20043

We present results on the photoproduction of 10 000 charmed particles from the 108 recorded triggers of Fermilab experiment E691. The total cross section for the photoproduction of D0 and D+ particles (and antiparticles) for xF>0.2 is measured to be 3.88±0.06±0.40 μb/Be nucleus at 〈Eγ〉=145 GeV. We have also measured the relative production of different charmed particles, their pT2 and xF distributions, and the energy dependence of the total charm cross section. The mean pT2 is 1.16±0.04 GeV2/c2 and the ratio of charm cross sections at 200 and 100 GeV is 1.96±0.24. Results of fits to the xF distribution are also reported.

12 data tables
Table 1

D0/AD0 cross section from K-PI+/K+PI- decay mode.

Table 2

D+/D- cross section from K-2PI+/K+2PI- decay mode.

Table 3

D*+/D*- cross section from D0<K-PI+>PI+ + CC decay mode.

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Search for Narrow Baryonia With Negative and Positive Strangeness

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.
Z.Phys.C 47 (1990) 533-537, 1990.
Inspire Record 285796 DOI 10.17182/hepdata.15148

A search for baryonia with negative and positive strangeness decaying respectively into\(\Lambda+ \bar p + pions\) and\(\bar \Lambda+ p + pions\) has been carried out in a neutron beam with a mean momentum of ≅40 GeV/c in an experiment performed at the Serpukhov accelerator. There is a strong indication of the existence of these baryonia. The following four charge states are observed for negative and positive strangeness: neutral, negative, positive and doubly charged. Their mean mass is 3055±25 MeV/c2 and the width Γ≦36±15 MeV/c2. The data show that the isotopic spin of the baryonia is ≧3/2. The baryonia production cross sections in the acceptable kinematic regionXF≧0.2 andPT≦1 GeV/c times the branching ratios of the observed decays are of the order of 1 μb per nucleon.

1 data table
Table 1

No description provided.


Hidden Strangeness in the Proton? Determination of the Real Part of the Isospin Even - Forward Scattering Amplitude of Pion Nucleon Scattering at 54.3-{MeV}

Wiedner, U. ; Goring, K. ; Jaki, J. ; et al.
Phys.Rev.D 40 (1989) 3568-3581, 1989.
Inspire Record 287810 DOI 10.17182/hepdata.23079

The contradiction of the σ term of pion-nucleon scattering as deduced from the Karlsruhe-Helsinki phase shifts with the smaller value calculated by the chiral perturbation theory of QCD is well known. In an effort to clarify the discrepancy we have determined the real part of the isospin-even forward-scattering amplitude of pion-nucleon scattering at a pion energy Tπ=54.3 MeV by measurement of the elastic scattering of positive and negative pions on protons in the Coulomb-nuclear interference region. The deduced value is in agreement with the prediction of the Karlsruhe-Helsinki phase-shift analysis for that energy. The resulting large value of the σ term may be interpreted as being due to the influence of s¯s sea pairs even at large distances (small Q2) as previously suggested by the European Muon Collaboration measurement of deep-inelastic scattering of polarized muons on polarized protons.

1 data table
Table 1

No description provided.


K0(S) PRODUCTION IN ANTI-P P INTERACTIONS AT S**(1/2) = 630-GeV AND 1800-GEV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.
Phys.Rev.D 40 (1989) 3791-3794, 1989.
Inspire Record 287811 DOI 10.17182/hepdata.22999

Measurements of inclusive transverse-momentum spectra for KS0 mesons produced in proton-antiproton collisions at s of 630 and 1800 GeV are presented and compared with data taken at lower energies. The ratio, as a function of pT, of the cross section for KS0 to that for charged hadrons is very similar to what is observed at lower energies. At 1800 GeV, we calculate the strangeness-suppression factor λ=0.40±0.05.

4 data tables
Table 1

Estimated effective cross sections for events which pass the trigger and selection criteria. The uncertainties in these represent the principal source of error in the overall normalisation of the results.

Table 2

Statistical errors only.

Table 3

Statistical errors only.

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DIFFERENTIAL CROSS-SECTION FOR PI- P ---> GAMMA N FROM 427-MEV/C TO 625-MEV/C

Kim, G.J. ; Arends, J. ; Briscoe, W.J. ; et al.
Phys.Rev.D 40 (1989) 244-247, 1989.
Inspire Record 285141 DOI 10.17182/hepdata.23110

Differential cross sections for π−p→γn have been determined from 427 to 625 MeV/c, mainly at 90° and 110° c.m. The data were obtained by combining measurements of the Panofsky ratio in flight with known charge-exchange cross sections. The results are compared with γn→π−p data derived from γd experiments; the difference is typically 30%. The radiative decay amplitudes of neutral πN resonances are therefore uncertain by at least 30%.

3 data tables
Table 1

Charge exchange cross section from PWA.

Table 2

PI- P --> GAMMA N cross section.

Table 3

GAMMA N --> PI- P cross section calculated using detailed balance.


MEASUREMENT OF alpha-s FROM HADRON JETS IN e+ e- ANNIHILATION AT S**(1/2) OF 29-GeV

Ford, William T. ; Qi, N. ; Read, Alexander L. ; et al.
Phys.Rev.D 40 (1989) 1385, 1989.
Inspire Record 276788 DOI 10.17182/hepdata.23112

A study of the lateral development of jets of hadrons produced in electron-positron annihilation has been used to determine the strong coupling constant αs. Data were obtained with the MAC detector at the SLAC e+e− storage ring PEP at s=29 GeV. Based on the parton calculations of Gottschalk and Shatz, a value for αs of 0.133±0.005(stat)±0.009(syst) has been determined for string fragmentation, and 0.112±0.008(stat)±0.007(syst) for an independent-jet model.

2 data tables
Table 1

JET FRACTION MEASURED. FIT ACCORDING TO:. T.D. GOTTSCHALK AND M.P.SCHATZ CALT-68-1172 (1985).

Table 2

JET FRACTION MEASURED. FIT ACCORDING TO INDEPENTENT JET MODEL.


INCLUSIVE CHARGED D* PRODUCTION IN 205-GEV/C PI- BE INTERACTIONS

Mooney, P. ; Sarmiento, M. ; Bishop, J.M. ; et al.
Phys.Rev.D 39 (1989) 2494-2498, 1989.
Inspire Record 282266 DOI 10.17182/hepdata.23225

The inclusive cross section for charged-D* production by 205-GeV/c π− mesons incident on a beryllium target was measured with a two-arm spectrometer triggered by prompt muons. Using the mass-difference technique often employed in D* studies, a signal of 31±11 charged D*’s was isolated; it includes contributions from both the D*+ and D*− charged modes in correlation with triggering muons of the proper charge. This corresponds to an inclusive charged-D* production cross section of 220±77−57+77 μb per Be nucleus or 24±9−6+9 μb per nucleon when the cross section is scaled linearly with atomic mass number. The first error is statistical and the second is systematic.

1 data table
Table 1

No description provided.


Polarization in Inclusive $\Lambda$ and $\bar{\Lambda}$ Production at Large $p_T$

Lundberg, B. ; Handler, R. ; Pondrom, L. ; et al.
Phys.Rev.D 40 (1989) 3557-3567, 1989.
Inspire Record 287809 DOI 10.17182/hepdata.23077

A study of the inclusive polarization of Λ hyperons produced by 400-GeV/c protons incident on nuclear targets has been performed at Fermilab. The polarization P of the Λ has been mapped over a large range of xF and pT to good precision for pT up to 3.8 GeV/c. The magnitude of the polarization at fixed xF rises with pT to a plateau at about 1 GeV/c, and the size of the plateau increases monotonically with xF. The Λ¯ were found to be unpolarized for pT<2.4 GeV/c. A target-nucleus dependence for the Λ polarization has been observed.

17 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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