We calculate the two-loop contributions to the electric dipole moments of the electron and the neutron mediated by charged Higgs in a generic supersymmetric theories. The new contributions are ...originated from the potential CP violation in the trilinear couplings of the charged Higgs bosons to the scalar-top or the scalar-bottom quarks. These couplings did not receive stringent constraints directly. We find observable effects for a sizable portion of the parameter space related to the third generation scalar-quarks in the minimal supersymmetric standard model.
2+1-dimensional Yang–Mills theory is reinterpreted in terms of metrics on 3-manifolds. The dual gluons are related to diffeomorphisms of the 3-manifolds. Monopoles are identified with points where ...the Ricci tensor has triply degenerate eigenvalues. The dual gluons have the desired interaction with these monopoles. This would give a mass for the dual gluons resulting in confinement.
Searches for pair production of gauginos and squarks in $e^{+} e^{-}$ collisions at a centre-of-mass energy of 189 GeV have been performed on data corresponding to an integrated luminosity of 158 ...pb$^{-1}$ collected by the DELPHI detector at LEP. The data were analyzed under the assumption of non-conservation of \mbox{$R$-parity} through a single dominant $\bar{U} \bar{D} \bar{D}$~coupling between squarks and quarks. Typical final states contain between 4 and 10 jets with or without additional leptons. No excess of data above Standard Model expectations was observed. The results were used to constrain domains of the MSSM parameter space and derive limits on the masses of supersymmetric particles. The following mass limits at 95\% CL were obtained from these searches: \begin{itemize} \item neutralino mass: $m_{\tilde{\chi^0_{1}}} \ge 32$ GeV \item chargino mass: $m_{\tilde{\chi^+_{1}}} \ge 94 $ GeV \item stop and sbottom mass (indirect decay) with $\Delta M 5$ GeV: $m_{\tilde{t_{1}}} \ge 74$ GeV, for $\Phi_{mix}=0$ rad $m_{\tilde{t_{1}}} \ge 59$ GeV, for $\Phi_{mix}=0.98 $ rad $m_{\tilde{b_{1}}} \ge 72$ GeV, for $\Phi_{mix}=0$ rad. \end{itemize} The angle $\phi_{mix}$ is the mixing angle between left and right handed quarks.
Performance of the DELPHI detector Abreu, P.; Ajinenko, I.; Aleksan, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1996, Letnik:
378, Številka:
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Journal Article
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Odprti dostop
DELPHI (DEtector with Lepton, Photon and Hadron Identification) is a detector for e
+e
− physics, designed to provide high granularity over a 4π solid angle, allowing an effective particle ...identification. It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.
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 ̄ events, 〈n〉 b b ̄ , and the difference δ bl between 〈n〉 b b ̄ and the multiplicity, 〈n〉 l l ̄ , in generic light quark (u,d,s) events: δ bl (183 GeV) =4.55±1.31( stat )±0.73( syst ) , δ bl (189 GeV) =4.43±0.85( stat )±0.61( syst ) , δ bl (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. (Elsevier)
The study of the directional dependence of two-particle correlations in the hadronic decays of the $Z^0$ boson is performed using the data collected by the DELPHI experiment in the 1992--1995 running ...periods. The comparison between the transverse, $R_{\perp}$, and longitudinal, $R_{\parallel}$, correlation radii confirms the string model prediction that the transverse correlation length is smaller than the longitudinal one, with the measured values of $R_{\perp}=0.53\pm 0.08\,\mathrm{fm}$ and $R_{\parallel}=0.85\pm 0.08\,\mathrm{fm}$, for selected $Z^0\rightarrow q\bar{q}$ events.
The rapidity-rank structure of \ppb pairs is used to analyze the mechanism of baryon production in hadronic \zz decay. The relative occurrence of the rapidity-ordered configuration \pmpb, where $M$ ...is a meson, and that of \ppb adjacent pairs is compared. The data are found to be consistent with predictions from a mechanism producing adjacent-rank \ppb pairs, without requiring `string-ordered' \pmpb configurations. An upper limit of 15\% at 90\% confidence is determined for the \pmpb contribution.