E Merle

Publications (437)73.64 Total impact

• Article: Limits on the Masses of Supersymmetric Particles at $\sqrt{s}$=189 GeV

  P Abreu, W Adam, T Adye, P Adzic, I Ajinenko, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Searches for charginos, neutralinos and sleptons at LEP2 centre-of-mass energies from 130 GeV to 189 GeV have been used to set lower limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles within the MSSM framework. R-parity conservation has been assumed. The lightest neutralino was found to be heavier than 32.3~\mbox{$ {\mathrm{GeV}}/c^2$} independent of the $m_0$ value. The lightest chargino, the second-to-lightest neutralino, the next-to-heaviest neutralino, the heaviest neutralino, the sneutrino and the right-handed selectron %{\mbox{$ {\tilde{\mathrm e}_R} $}} were found to be heavier than 62.4~\mbox{$ {\mathrm{GeV}}/c^2$}, 62.4~\mbox{$ {\mathrm{GeV}}/c^2$}, 99.9~\mbox{$ {\mathrm{GeV}}/c^2$}, 116.0~\mbox{$ {\mathrm{GeV}}/c^2$}, 61.0~\mbox{$ {\mathrm{GeV}}/c^2$}, and 87.0 GeV=c$^{2}$ , respectively. These limits do not depend on m0 or M2 and are valid for 1 $\le tan\beta \le 40$, in the $\mu$ region where the lightest neutralino is the LSP. If the sneutrino is heavier than the chargino the lightest neutralino has to be heavier than 32.4 GeV=c 2 . The e ects of mixings in the third family of sfermions on these limits are discussed. The confidence level of all limits given is 95%.
• Article: Search for sleptons in $e^+ e^-$ collisions at $\sqrt{s}$= 183 to 189 GeV

  P Abreu, W Adam, T Adye, P Adzic, I Ajinenko, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Data taken by the {\tt DELPHI} experiment at centre-of-mass energies of 183~\GeV\ and 189~\GeV\ with a total integrated luminosity of 212 pb$^{-1} have been used to search for the supersymmetric partners of the electrons, muons, and taus in the context of the Minimal Supersymmetric Standard Model (MSSM). The decay topologies searched for were the direct decay ({\tilde \ell} -> \ell {\tilde\chi_1^0}), producing acoplanar lepton pairs plus missing energy, and the cascade decay ({\tilde \ell} -> \ell {\tilde \chi_2^0} -> \ell\gamma {\tilde \chi_1^0}), producing acoplanar lepton and photon pairs plus missing energy. The observed number of events is in agreement with Standard Model predictions. The 95% CL excluded mass limits for selectrons, smuons and staus are m_{\tilde {e}\leq 87 GeV/c^2, m_{\tilde {\mu}} \leq 80 GeV/c^2 and m_{\tilde {\tau}} \leq 75 GeV/c^2, respectively, for values of \mu=-200 GeV/c^2 and tan(beta)=1.5.
• Article: Update of the search for supersymmetric particles in scenarios with Gravitino LSP and Sleptons NLSP

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: An update of the search for sleptons, neutralinos and charginos in the context of scenarios where the lightest supersymmetric particle is the gravitino and the next-to-lightest supersymmetric particle is a slepton, is presented, together with the update of the search for heavy stable charged particles in light gravitino scenarios and Minimal Supersymmetric Standard Models. Data collected in 1999 with the DELPHI detector at centre-of-mass energies around 192, 196, 200 and 202 GeV were analysed. No evidence for the production of these supersymmetric particles was found. Hence, new mass limits were derived at 95% confidence level.
• Article: Measurement of the Mass and Width of the W Boson in $e^+ e^-$ Collisions at $\sqrt{s}$ = 189 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: A measurement of the W mass and width has been performed by the DELPHI collaboration using the data collected during 1998. The data sample has an integrated luminosity of 155 pb^{-1} and an average centre-of-mass energy of 188.6 GeV. Results are obtained by applying the method of direct reconstruction of the mass of the W from its decay products in both the W+W- -> lvqq and W+W- -> qqqq channels. The W mass result for the 1998 data set is M_W = 80.387 +/- 0.087 (stat) +/- 0.034 (syst) +/- 0.017 (LEP) +/- 0.035 (FSI) GeV/c2, where FSI represents the uncertainty due to final state interaction effects in the qqqq channel, and LEP represents that arising from the knowledge of the beam energy of the accelerator. Combining this result with those previously published by the DELPHI collaboration gives the result M_W = 80.359 +/- 0.074 (stat) +/- 0.032 (syst) +/- 0.017 (LEP) +/- 0.033 (FSI) GeV/c2. The combined value for the W width is \Gamma_W = 2.266 +/- 0.176 (stat) +/- 0.056 (syst) +/- 0.052 (FSI) GeV/c2.
• Article: Search for neutral MSSM Higgs bosons at LEP

  S Schael, R Barate, R Brunelière, I De Bonis, D Décamp, C Goy, S Jézéquel, J P Lees, F Martin, E Merle, [......], N Wermes, G W Wilson, J A Wilson, T R Wyatt, S Yamashita, D Zer-Zion, L Zivkovic, S. Heinemeyer, A. Pilaftsis, G. Weiglein
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  ABSTRACT: The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of ``benchmark" models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter tanb and, in some scenarios, on the masses of neutral Higgs bosons.
• Article: Determination of the $e^+ e^- \to \gamma \gamma(\gamma)$ cross-section at centre-of-mass energies ranging from 189 GeV to 202 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: A test of the QED process \eeintogg(\fot) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest ener\-gies achieved at LEP, reaching 202 GeV in the centre-of-mass. The total integrated luminosity amounts to 375.7 pb$^{-1}$. The differential and total cross-sections for the process $e^+e^- \to \gamma \gamma$ were measured, and found to be in agreement with the QED prediction. 95\% Confidence Level (C.L.) lower limits on the QED cut-off parameters of $\rm \Lambda_+ >$ 330 GeV and $\rm \Lambda_{-}>$ 320 GeV were derived. A 95\% C.L. lower bound on the mass of an excited electron of 311 $\rm GeV/c^2$ (for $\lambda_{\gamma}$ =1) was obtained. s-channel virtual graviton exchange was searched for, resulting in 95\% C.L. lower limits on the string mass scale, $\rm M_S$: $\rm M_S > 713 \, GeV/c^2$ ( $\lambda=1$) and $\rm M_S > 691 \,GeV/c^2$ ($\lambda = -1$).
• Article: A search for invisible Higgs bosons produced in $e^{+} e^{-}$ interactions up to $\sqrt{s}$ = 189 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Searches for {\mbox{$ {\mathrm H} {\mathrm Z} $}} production d with the Higgs boson decaying into an invisible final state have been performedd the data collected by the DELPHI experimentd up to the centre-of-mass energy of 188.6~{\mbox{$ {\mathrm{GeV}}$}}. d The hadronic and muon pair final states of the d {\mbox{$ {\mathrm Z} $}} d boson were analysed. No signal was found. d Upper limits on the cross-section and the corresponding Higgs boson mass d limits were set d at 95\% confidence level. Combining these results with DELPHI results for the vd a 95\% confidence level Higgs mass lower limit of 92.3~{\mbox{$d {\mathrm{GeV}}$}} was obtained, independentd of the branching ratio into visible and invisible decays.
• Article: Measurement of Trilinear Gauge Boson Couplings $WWV, (V \equiv Z, \gamma)$ in $e^+ e^-$ Collisions at 189 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Measurements of the trilinear gauge boson couplings $WW\gamma$ 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 \Dgz\ and \Dkg, the differences of the $WWZ$ charge coupling and of the $WW\gamma$ dipole coupling from their Standard Model values, and for \lm, the $WW\gamma$ quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the $W$ is extracted from the results for \Dkg{} and \lm. The study uses data from the final states \jjlv, \jjjj \lX, \jjX\ and \gX, where $j$ represents a quark jet, $\ell$ an identified lepton and $X$ missing four-momentum. The observations are consistent with the predictions of the Standard Model.
• Article: Search for a fermiophobic Higgs at LEP 2

  P Abreu, W Adam, T Adye, P Adzic, I Ajinenko, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Higgs bosons predicted by the fermiophobic scenario within Two Higgs Doublets Models were searched for in the data collected by the DELPHI detector at centre-of-mass energies between 189 GeV and 202 GeV, corresponding to a total integrated luminosity of 380 pb^{-1}. No signal was found and confidence limits were derivedwska, Agni
• Article: Measurement and Interpretation of Fermion-Pair Production at LEP Energies of 183 and 189 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: An analysis of the data collected in 1997 and 1998 with the DELPHIdetector at $e^+e^-$ collision energies close to 183 and 189GeV was performed in order to extract the hadronic and leptonic fermion--paircross--sections, as well as the leptonic forward--backward asymmetries andangular distributions.The data are used to put limit on contact interactions between fermions,the exchange of R-parity violating SUSY sneutrinos, $\Zprime$ bosons and the existence of gravity in extra dimensions.
• Article: Search for SUSY with R-parity violating $LL\overline{E}$ couplings at $\sqrt{s}$=189 GeV

  P Abreu, W Adam, T Adye, P Adzic, Z Albrecht, T Alderweireld, G D Alekseev, R Alemany, T Allmendinger, P P Allport, [......], O P Yushchenko, A Zalewska-Bak, Piotr Zalewski, D Zavrtanik, E Zevgolatakos, N I Zimin, A I Zinchenko, P. Zoller, G Zumerle, M Zupan
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  ABSTRACT: Searches for pair production of supersymmetric particlesunder the assumption that $R$--parity is not conserved are presented,based on data recorded by the DELPHI detector in 1998from e$^{+}$e$^{-}$ collisions at a centre-of-mass energy of189~GeV. Only one $R$--parity violating $\rm{LL} \bar{\rm E}$term (i.e. one $\lambda$ coupling), which couples\mbox{scalar} leptons to leptons,is considered to be dominant at a time.Moreover, it is assumed that the strength of the $R$--parityviolating couplings is such that the lifetimes can be neglected.The search for pair production of neutralinos, charginos and sleptonshas been performed for both direct $R$--parity violating decaysand indirect cascade decays.The results are in agreement with Standard Model expectations, andare used to update the constraints on the MSSM parametervalues and the mass limits previously derived at \mbox{$\sqrt{s}$~=~183~GeV.}\\The present 95\% C.L. limits on supersymmetric particle masses are:\begin{malist}\item $m_{\tilde{\chi}^0}>~$30~\GeVcc\ and $m_{\tilde{\chi}^\pm}>$~94~\GeVcc;\item $m_{\tilde{\nu}}>$~76.5~\GeVcc \ (direct and indirect decays);\item $m_{\tilde{\ell}_R}>$~83~\GeVcc\ (indirect decay only).\end{malist}
• Article: Precision electroweak measurements on the Z resonance

  S Schael, R Barate, R Bruneliere, D Buskulic, I De Bonis, D Decamp, P Ghez, C Goy, S Jezequel, JP Lees, [......], RK Yamamoto, XQ Yang, J Yashima, SJ Yellin, CC Young, H Yuta, G Zapalac, RW Zdarko, C Zeitlin, J Zhou
  Michael Williams.
• Article: Precision Electroweak Measurements on the Z Resonance

  S Schael, R Barate, R Brunelière, Damir Buskulic, I De Bonis, D Décamp, P Ghez, C Goy, S Jézéquel, J P Lees, [......], R K Yamamoto, X Q Yang, J Yashima, S J Yellin, C C Young, H Yuta, G Zapalac, R W Zdarko, C Zeitlin, J Zhou
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  ABSTRACT: We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, $MZ$ and $GZ$, and its couplings to fermions, for example the $ ho$ parameter and the effective electroweak mixing angle for leptons, are precisely measured: egin{eqnarray*} MZ & = & 91.1875 pm 0.0021~GeV \ GZ & = & 2.4952 pm 0.0023~GeV \ ho_ell & = & 1.0050 pm 0.0010 \ swsqeffl & =& 0.23153 pm 0.00016 ,. end{eqnarray*} The number of light neutrino species is determined to be $2.9840pm0.0082$, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model. At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its Standard Model expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, $Mt=173^{+13}_{-10}~GeV$, and the mass of the W boson, $MW=80.363pm0.032~GeV$. These indirect constraints are compared to the direct measurements, providing a stringent test of the Standard Model. Using in addition the direct measurements of $Mt$ and $MW$, the mass of the as yet unobserved Standard Model Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than $285~GeV$ at 95% confidence level.
• Source

  Available from: Andrea Sciabà

  Article: Determination of the LEP centre-of-mass energy from Z$\gamma$ events

  R Barate, D Décamp, P Ghez, C Goy, S Jézéquel, J P Lees, F Martin, E Merle, M N Minard, B Pietrzyk, [......], P A McNamara, J Nielsen, W Orejudos, Y B Pan, Y Saadi, I J Scott, J Walsh, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: Radiative returns to the Z resonance (Z\gamma events) are used to determine the LEP2 centre-of-mass energy from the data collected with the ALEPH detector in 1997. The average centre-of-mass energy is measured to be: E_CM = 182.50 +- 0.19 (stat.) +- 0.08 (syst.) GeV in good agreement with the precise determination by the LEP energy working group of 182.652 +- 0.050 GeV. If applied to the measurement of the W mass, its precision translates into a systematic error on M_W which is smaller than the statistical error achieved from the corresponding dataset.
• Source

  Available from: Andrea Sciabà

  Article: Measurement of W-pair production in $e^{+}e^{-}$ collisions at 183 GeV

  R Barate, D Décamp, P Ghez, C Goy, S Jézéquel, J P Lees, F Martin, E Merle, M N Minard, B Pietrzyk, [......], J Nielsen, W Orejudos, Y B Pan, Y Saadi, I J Scott, M Vogt, J Walsh, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: The production of W+W- pairs is analysed in a data sample collected by ALEPH at a mean centre-of-mass energy of 182.7 GeV, corresponding to an integrated luminosity of 57 pb-1. Cross sections are given for different topologies of W decays into leptons or hadrons. Under Standard Model assumptions for the W-pair production and decay, the W-pair cross section is measured to be 15.57+-0.62(stat.)+-0.29(syst.) pb. Using also the W-pair data samples collected by ALEPH at lower centre-of-mass energies, the decay branching ratio of the W boson into hadrons is measured to be B(W->hadrons)= 68.93+-1.21(stat.)+-0.51(syst.)%, allowing a determination of the CKM matrix element |Vcs|= 1.043 +- 0.058(stat.) +- 0.026(syst.). The agreement of the cross sections with the Standard Model prediction allows a limit to be set on the W decay rate to undetectable final states.
• Source

  Available from: Andrea Sciabà

  Article: Search for scalar leptons in $e^+ e^-$ collisions at centre-of-mass energies up to 209 GeV

  A Heister, S Schael, R Barate, R Brunelière, I De Bonis, D Décamp, C Goy, S Jézéquel, J P Lees, F Martin, [......], J Kile, P A McNamara, J Nielsen, Y B Pan, J H Von Wimmersperg-Töller, W Wiedenmann, J Wu, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: A search for selectron, smuon and stau pair production is performed with the data collected by the ALEPH detector at LEP at centre-of-mass energies up to 209 GeV. The numbers of candidate events are consistent with the background predicted by the Standard Model. Final mass limits from ALEPH are reported.
• Article: The forward-backward asymmetry for charm quarks at the Z

  R. Barate, D. Buskulic, D. Decamp, P. Ghez, C. Goy, J.-P. Lees, A. Lucotte, E. Merle, M.-N. Minard, J.-Y. Nief, [......], J.M. Nachtman, J. Nielsen, W. Orejudos, Y.B. Pan, Y. Saadi, I.J. Scott, J. Walsh, Sau Lan Wu, X. Wu, G. Zobernig
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  ABSTRACT: The data set collected with the ALEPH detector from 1991 to 1995 at LEP has been analysed to measure the charm forward-backward asymmetry at the Z. Out of a total of 4.1 million hadronic Z decays, about 36000 high momentum , D+ and D0 decays were reconstructed, of which 80% originate from events. The forward-backward asymmetry was measured at three energy points:From this analysis, a value of the effective electroweak mixing angle sin2θeffW=0.2321±0.0016 is extracted.
  Physics Letters B.
• Article: Study of $D^{0}-\overline{D}^{0}$ mixing and $D^{0}$ doubly-Cabibbo-suppressed decays

  R Barate, Damir Buskulic, D Décamp, P Ghez, C Goy, J P Lees, A Lucotte, E Merle, M N Minard, J Y Nief, [......], J M Nachtman, J Nielsen, W Orejudos, Y B Pan, Y Saadi, I J Scott, J Walsh, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: Using a sample of four million hadronic Z events collected in ALEPH from 1991 to 1995, the decays D^{*+} --> D^0 pi_{s}^+, with D^0 decaying to K^- pi^+ or to K^+ pi^-, are studied. The relative br anching ratio $B(\D^0 \to \K^+ \pi^-) / B(\D^0 \to \K^- \pi^+)$ is measured to be ( 1.84 \pm 0.59(\stat) \pm 0.34(\syst). The two possible contributions to the $\decDW$ decay, doubly Cabibbo-suppr essed decays and D^0-$D^0bar mixing, are disentangled by measuring the proper-time distribution of the reconstructed D^0's. Assuming no interference between the two processes, the upper limit obtai ned on the mixing rate is 0.92% at 95 % CL. The possible effect of interference between the two amplitudes is also assessed.
• Article: Measurement of the spectral functions of axial-vector hadronic $\tau$ decays and determination of $\alpha_{s}(M^2_\tau)$

  R Barate, Damir Buskulic, D Décamp, P Ghez, C Goy, J P Lees, A Lucotte, E Merle, M N Minard, J Y Nief, [......], J M Nachtman, J Nielsen, W Orejudos, Y B Pan, Y Saadi, I J Scott, J Walsh, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: An analysis based on 124000 selected tau pairs recorded by the ALEPH detector at LEP provides the vector (V) and axial-vector (A) spectral functions of hadronic tau decays together with their total widths. This allows the evaluation of finite energy chiral sum rules that are weighted integrals over the (V-A) spectral functions. In addition, a precise measurement of alpha_s along with a determination of nonperturbative contributions at the tau mass scale is performed. The experimentally and theoretically most robust determination of alpha_s(M_tau^2) is obtained from the (V+A) fit that yields alpha_s(M_tau^2) = 0.334 +/- 0.022 giving alpha_s(M_Z^2) = 0.1202 +/- 0.0027 after the extrapolation to the mass of the Z boson. The approach of the Operator Product Expansion (OPE) is tested experimentally studying the evolution of the tau hadronic widths to masses smaller than the tau mass.
• Article: Measurements of the structure of quark and gluon jets in hadronic Z decays

  R Barate, Damir Buskulic, D Décamp, P Ghez, C Goy, J P Lees, A Lucotte, E Merle, M N Minard, J Y Nief, [......], J M Nachtman, J Nielsen, W Orejudos, Y B Pan, Y Saadi, I J Scott, J Walsh, Wu Sau Lan, X Wu, G Zobernig
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  ABSTRACT: An experimental investigation of the structure of identified quark and gluon jets is presented. Observables related to both the global and internal structure of jets are measured; this allows for tests of QCD over a wide range of transverse momentum scales. The observables include distributions of jet-shape variables, the mean and standard deviation of the subjet multiplicity distribution and the fragmentation function for charged particles. The data are compared with predictions of perturbative QCD as well as QCD-based Monte Carlo models. In certain kinematic regions the measurements are sensitive mainly to perturbatively calculable effects, allowing for a test of QCD. The comparisons are also extended into regions where nonperturbative effects become large, and in this way the transition from hard to soft QCD is investigated. It is found that by including leading and next-to-leading logarithmic contributions in the QCD predictions, the agreement with the data can be extended to lower transverse momentum scales, especially for gluon jets.