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Search for new phenomena using single photon events in the DELPHI detector at LEP

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 74 (1997) 577-586, 1997.

Inspire Record 415746 DOI 10.17182/hepdata.41128

Data are presented on the reaction e+e− → γ + no other detected particle at centre-of-mass energies of 89.48, 91.26 and 93.08 GeV. The cross-section for this reaction is related directly to the number of light neutrino generations which couple to the Z° boson, and to several other possible phenomena such as the production of excited neutrinos, the production of any invisible ‘X’ particle, and the magnetic moment of the tau neutrino. Based on the observed number of single photon events, the number of light neutrinos that couple to the Z° is measured to be Nv = 2.89 ± 0.38. No evidence is found for anomalous production of energetic single photons, and upper limits at 95% confidence level are determined for excited neutrino production (BR < 4 − 8 × 10−6 depending on its mass), production of an invisible ‘X’ particle (σ, < 0.1 pb for masses below 60 GeV), and the magnetic moment of the tau neutrino (< 5.1 × 10-6 μB).

3 data tables

Table 1

No description provided.

Table 2

Limit on an anomalous magnetic moment for tau-neutrino from '1GAMMA + nothing' events. Magnetic moment in Bohr magnetons.

Table 3

Here UNSPEC is invisible particle.

Interferometry results from the CERN WA98 experiment

Rosselet, L. ; Angelis, A.L.S. ; Doenni, P. ; et al.

Nucl.Phys.A 610 (1996) 256C-263C, 1996.

Inspire Record 432737 DOI 10.17182/hepdata.36463

None

1 data table

Table 1

PRELIMINARY DATA. THE DISTRIBUTION (1/PT)*D(N)/D(PT) HAS BEEN FITTED BY A FORMULA SQRT(MT)*K1(SLOPE*MT), WHERE K1 IS THE MAKDONALD FUNCTION.

Hadron distributions: Recent results from the CERN experiment NA44

The NA44 collaboration Xu, Nu ; Bearden, I.G. ; Bøggild, H. ; et al.

Nucl.Phys.A 610 (1996) 175C-187C, 1996.

Inspire Record 432743 DOI 10.17182/hepdata.36469

Proton distributions at midrapidity have been measured for 158A·GeV Pb+Pb collisions in the focusing spectrometer experiment NA44 at CERN. A high degree of nuclear stopping is found in the truly heavy ion collisions. Systematic results of single particle transverse momentum distributions of pions, kaons, and protons, of 200A·GeV S+S and 158A·GeV Pb+Pb central collisions will be addressed within the context of thermalization. By comparing these data with thermal and transport models, freeze-out parameters such as the temperature parameter T fo and mean collective flow velocity 〈β〉 are extracted. Preliminary results of the particle ratios of K − K + and p p are discussed in the context of cascade models of RQMD and VENUS.

1 data table

Table 1

CENTRAL COLLISIONS: SIG(TRIG)/SIG(GEOM)=10%.

Strangelet search and antinuclei production studies in Pb + Pb collisions

The NA52 (NEWMASS) collaboration Ambrosini, G. ; Appelquist, G. ; Arsenescu, R. ; et al.

Nucl.Phys.A 610 (1996) 306C-316C, 1996.

Inspire Record 432734 DOI 10.17182/hepdata.36512

We searched for long-lived strange quark matter particles, so-called strangelets , and studied particle and antiparticle production in Pb + Pb collisions at 158 GeV/ c per nucleon at zero degree production angle. We give upper limits for the production of strangelets covering a mass to charge ratio up to 120 GeV/ c 2 and lifetimes t lab > 1.2 μ s and plot invariant differential production cross sections as a function of rapidity for a variety of particles.

1 data table

Table 1

No description provided.

WA97 results on strangeness production in lead lead collisions at 158-A-GeV/c

The WA97 collaboration Andersen, E. ; Andrighetto, A. ; Antinori, F. ; et al.

Nucl.Phys.A 610 (1996) 165C-174C, 1996.

Inspire Record 432744 DOI 10.17182/hepdata.36503

Preliminary results from WA97 measurements on Λ, Ξ and Ω production in lead-lead and proton-lead collisions are presented, along with a comparison of WA97 proton-lead data with previous WA85 proton-tungsten results. The ratio Ω gX seems to be enhanced in lead initiated reactions compared to proton initiated reactions.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

PRELIMINARI DATA.

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