J. Van Eldik

Measurement of trilinear gauge boson couplings WWV, (V Z,gamma) in e(+)e(-) collisions at 189 GeV

Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identified lepton and X missing four-momentum. The observations are consistent with the predictions of the Standard Model.

Inclusive

Production of Sigma- and Lambda(1520) in hadronic Z decays has been measured using the DELPHI detector at LEP. The Sigma- is directly reconstructed as a charged track in the DELPHI microvertex detector and is identified by its Sigma -> n pi decay leading to a kink between the Sigma- and pi-track. The reconstruction of the Lambda(1520) resonance relies strongly on the particle identification capabilities of the barrel Ring Imaging Cherenkov detector and on the ionisation loss measurement of the TPC. Inclusive production spectra are measured for both particles. The production rates are measured to be = 0.081 +/- 0.002 +/- 0.010, = 0.029 +/- 0.005 +/- 0.005. The production rate of the Lambda(1520) suggests that a large fraction of the stable baryons descend from orbitally excited baryonic states. It is shown that the baryon production rates in Z decays follow a universal phenomenological law related to isospin, strangeness and mass of the particles.

\Sigma^-

From the data collected by DELPHI at LEP in autumn 1995, the multiplicity of charged particles at a hadronic energy of 130 GeV has been measured to be 〈nch〉 = 23.84 ± 0.51 (stat) ± 0.52 (syst). When compared to lower energy data, the value measured is consistent with the evolution predicted by QCD with corrections at next-to-leading order, for a value αs(130 GeV) = 0.105 ± 0.003 (stat) ± 0.008 (syst).

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CERN has been running a production OpenStack cloud since July 2013 to support physics computing and infrastructure services for the site. In the past year, CERN Cloud Infrastructure has seen a constant increase in nodes, virtual machines, users and projects. This paper will present what has been done in order to make the CERN cloud infrastructure scale out.

\Lambda(1520)

The DELPHI detector at LEP has collected 54 pb(-1) of data at a centre-of-mass energy around 183 GeV during 1997, 158 pb(-1) around 189 GeV during 1998, and 187 pb(-1) between 192 and 200 GeV during 1999. These data were used to measure the average charged particle multiplicity in e(+)e(-)→b (b) over bar events: (n)(b (b) over bar), and the difference delta(hl) between (n)(b (b) over bar) and the multiplicity, (n)(l (l) over bar), in generic light quark (u,d,s) events: delta(hl)(183 GeV) = 4.55 +/- 1.31(stat) +/- 0.73(syst), delta(hl)(189 GeV) = 4.43 +/- 0.85(stat) +/- 0.61(syst), delta(hl)(200 GeV) = 3.39 +/- 0.89(stat) +/- 1.01 (syst). This result is consistent with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the: mass of the quark itself.

production in hadronic Z decays

Abstract A search for stable or long-lived heavy charged particles in e + e − interactions at energies of 130–136, 161 and 172 GeV has been performed using the data taken by the DELPHI experiment at LEP. The search is based on particle identification provided by the Time Projection Chamber and the Ring Imaging Cherenkov detector. Upper limits at 95% confidence level are derived on the cross-section for heavy long-lived pair-produced charge ± e and ± 2 3 e particles in the range of 0.4–2.3 pb for masses from 45 to 84 GeV/ c 2 . Within supersymmetric extensions of the Standard Model, long-lived charginos with masses from 45 to 84 (80) GeV/ c 2 for high (low) sneutrino masses can be excluded at 95% confidence level. Left-handed (right-handed) long-lived or stable smuons and staus with masses between 45 and 68 (65) GeV/ c 2 can be excluded at 95% confidence level.

Charged particle multipicity in e+e- interactions at sqrt{s}=130 GeV

Abstract. Searches for pair production of supersymmetric particles in e

Scaling the CERN OpenStack cloud

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Hadronization properties of b quarks compared to light quarks in e(+)e(-)→ q(q)over-bar from 183 to 200 GeV

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Search for stable heavy charged particles in e(+)e(-) collisions at root s=130-136, 161 and 172 GeV

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