Results from the Lena Detector on the Y and Y′ Resonances

Niczyporuk, B.; Żeludziewicz, T.; Vogel, H.; Wegener, H.; Chen, K. W.; Hartung, R.; Bienlein, J. K.; Graumann, R.; Krüger, J.; Leissner, M.; Schmitz, M.; Rippich, C.; Filos, E.; Heimlich, F. H.; Nernst, R.; Schwarz, A. S.; Strohbusch, U.; Zschorsch, P.; Engler, A.; Kraemer, R.W.; Messing, F.; Ridge, T.; Stacey, B.J.; Youssef, S.; Fridman, A.; Alexander, G.; Av-Shalom, A.; Bella, G.; Gnat, Y.; Grunhaus, J.; Hörber, E.; Langguth, W.; Scheer, M.

doi:10.1063/1.2947491

Cited by 4 publications

(5 citation statements)

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“…In the region from the J/ψ to the Υ R-measurements are available from Mark I [95,96], DASP [97], PLUTO [98], LENA [99], Crystal Ball (CB) [100] and MD-1 [101] (see Fig. 7).…”

Section: The E + E − Data and The Origin Of Systematic Errorsmentioning

confidence: 99%

Hadronic contributions to (g?2) of the leptons and to the effective fine structure constant ?(M Z 2 )

Eidelman

Jegerlehner

1995

Z. Phys. C - Particles and Fields

495

701

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The new experiment planned at Brookhaven to measure the anomalous magnetic moment of the muon a µ ≡ (g µ − 2)/2 will improve the present accuracy of 7 ppm by about a factor of 20. This requires a careful reconsideration of the theoretical uncertainties of the g −2 predictions, which are dominated by the error of the contribution from the light quarks to the photon vacuum polarization. This issue is crucial also for the precise determination of the running fine structure constant at the Z-peak as LEP/SLC experiments continue to increase their precision. In this paper we present an updated analysis of the hadronic vacuum polarization using all presently available e + e − data. This seems to be justified because previous work on the subject was based to some extent on preliminary or incomplete experimental data. Contributions from different energy ranges are presented separately for g −2 of the muon and the τ -lepton and for α(M 2 Z ). We obtain the results a had * µ = (725±16)×10 −10 and a had * τ = (351 ± 10) × 10 −8 , where the asterisk indicates the dressed (renormalization group improved) value. For the effective fine structure constant at M Z = 91.1888 GeV we obtain ∆α (5) had = 0.0280 ± 0.0007 and α(M 2 Z ) −1 = 128.896 ± 0.090. Further improvement in the accuracy of theoretical predictions which depend on the hadronic vacuum polarization requires more precise measurements of e + e − cross-sections at energies below about 12 GeV in future experiments.

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“…In the region from the J/ψ to the Υ R-measurements are available from Mark I [95,96], DASP [97], PLUTO [98], LENA [99], Crystal Ball (CB) [100] and MD-1 [101] (see Fig. 7).…”

Section: The E + E − Data and The Origin Of Systematic Errorsmentioning

confidence: 99%

Hadronic contributions to (g?2) of the leptons and to the effective fine structure constant ?(M Z 2 )

Eidelman

Jegerlehner

1995

Z. Phys. C - Particles and Fields

495

701

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“…We considered only published results obtained in the continuum, thus away from the J/Ψ and Υ resonances, which were determined following what is now considered a standard convention [57], namely including in the evaluation of the mean value all charged particles produced in the decays of particles with lifetimes shorter than 3 · 10 −10 sec. [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. This means that the charged decay products of K 0 s and of weakly decaying heavy-mesons (D,B, .…”

Section: Test Of Mlla Predictions For B Quark Jetsmentioning

confidence: 99%

Multiplicity difference between heavy- and light-quark jets revisited

et al. 2005

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The perturbative QCD approach to multiparticle production predicts a characteristic suppression of particle multiplicity in a heavy quark jet as compared to a light quark jet. In the Modified Leading Logarithmic Approximation (MLLA) the multiplicity difference δ Qℓ between heavy and light quark jets is derived in terms of a few other experimentally measured quantities. The earlier prediction for b-quarks needs revision in the light of new experimental results and the improvement in the understanding of the experimental data. We now find δ bℓ = 4.4 ± 0.4. The updated MLLA results on δ bℓ and δ cℓ are compared with the present data from e + e − annihilation. Their expected energy independence is confirmed within the energy range between 29 and 200 GeV; the absolute values are now in better agreement with experiment than in the previous analysis, and the remaining difference can be attributed largely to next-to-MLLA contributions, an important subset of which are identified and evaluated.

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“…-At higher energy the total cross section ratio R is measured inclusively. We use the data provided by the experiments γγ2 [56], MARK I [57], DELCO [58], DASP [59], PLUTO [60], LENA [61], Crystal Ball [62], MD-1 [63], CELLO [64], JADE [65], MARK-J [66], TASSO [67], CLEO [68], CUSB [69] and MAC [70]. Above 3.5 GeV the measurements of the MARK I Collaboration are significantly higher than those from LENA, PLUTO and Crystal Ball.…”

Section: The Origin Of the Datamentioning

confidence: 99%

Improved determination of the hadronic contribution to the muon ( ${g-2}$) and to ${\alpha(M_{\mathrm Z}^2)}$ Using new data from hadronic $\tau$ decays

Alemany¹,

Davier²,

Höcker³

1998

Eur. Phys. J. C

200

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We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon (g − 2) and to the running of the QED fine structure constant α(s) at s = M 2 Z . We incorporated new data from hadronic τ decays, recently published by the ALEPH Collaboration. In addition, compared to previous analyses, we use more extensive e + e − annihilation data sets. The integration over the total hadronic cross section is performed using experimental data up to 40 GeV and results from perturbative QCD above 40 GeV. The improvement from τ data concerns mainly the pion form factor, where the uncertainty in the corresponding integral could be reduced by more than a factor of two. We obtain for the lowest order hadronic vacuum polarization graph a had µ = (695.0 ± 15.0)×10 −10 and ∆α (5) had (M 2 Z ) = (280.9 ± 6.3)×10 −4 using e + e − data only. The corresponding results for combined e + e − and τ data are a had µ = (701.1 ± 9.4)×10 −10 and ∆α (5) had (M 2 Z ) = (281.7 ± 6.2) ×10 −4 , where the latter is calculated using the contribution from the five lightest quarks.

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Results from the Lena Detector on the Y and Y′ Resonances

Cited by 4 publications

References 0 publications

Hadronic contributions to (g?2) of the leptons and to the effective fine structure constant ?(M Z 2 )

Hadronic contributions to (g?2) of the leptons and to the effective fine structure constant ?(M Z 2 )

Multiplicity difference between heavy- and light-quark jets revisited

Improved determination of the hadronic contribution to the muon ( ${g-2}$) and to ${\alpha(M_{\mathrm Z}^2)}$ Using new data from hadronic $\tau$ decays

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