Date

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Measurement of the tau polarization at LEP

The ALEPH collaboration Heister, A. ; Schael, S. ; Barate, R. ; et al.
Eur.Phys.J. C20 (2001) 401-430, 2001.
Inspire Record 555653 DOI 10.17182/hepdata.49751

The polarisation of $\tau$'s produced in Z decay is measured using 160 pb$^{-1}$ of data accumulated at LEP by the ALEPH detector between 1990 and 1995. The variation of the polarisation with polar angle yields the two parameters ${\cal A}_e = 0.1504 \pm 0.0068 $ and ${\cal A}_{\tau} = 0.1451 \pm 0.0059$ which are consistent with the hypothesis of $e$-$\tau$ universality. Assuming universality, the value ${\cal A}_{e{-}\tau} = 0.1474 \pm 0.0045$ is obtained from which the effective weak mixing angle $\sin^2 {\theta_{\mathrm{W}}^{\mathrm{eff}}} =0.23147 \pm 0.00057 $ is derived.

1 data table

No description provided.


A Precise measurement of the tau polarization at LEP-1

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J. C14 (2000) 585-611, 2000.
Inspire Record 511443 DOI 10.17182/hepdata.49001
2 data tables

The errors are statistical and systematic combined in quadrature.

No description provided.


Precision neutral current asymmetry parameter measurements from the tau polarization at LEP

The OPAL collaboration
Eur.Phys.J. C21 (2001) 1-21, 2001.
Inspire Record 554583 DOI 10.17182/hepdata.49765

Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e nu_e nu_tau, tau -> mu nu_mu nu_tau, tau -> pi nu_tau, tau -> rho nu_tau and tau -> a1 nu_tau decays from a sample of 144810 e+e- -> tau+ tau- candidates corresponding to an integrated luminosity of 151 pb-1. Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near Ecm = MZ to be <Ptau> = (-14.10 +/- 0.73 +/- 0.55)% and the tau polarization forward-backward asymmetry to be Afb = (-10.55 +/- 0.76 +/- 0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: Atau = 0.1456 +/- 0.0076 +/- 0.0057, Ae = 0.1454 +/- 0.0108 +/- 0.0036. These measurements are consistent with the hypothesis of lepton universality and combine to give Al = 0.1455 +/- 0.0073. Within the context of the Standard Model this combined result corresponds to sin^2(theta)(lept,effective) = 0.23172 +/- 0.00092. Combing these results with those from the other OPAL neutral current measurements yields a value of sin^2(theta)(lept,effective) = 0.23211 +/- 0.00068.

1 data table

No description provided.


An Improved direct measurement of leptonic coupling asymmetries with polarized Z bosons

The SLD collaboration Abe, Koya ; Abe, Kenji ; Abe, T. ; et al.
Phys.Rev.Lett. 86 (2001) 1162-1166, 2001.
Inspire Record 534735 DOI 10.17182/hepdata.41720

We present final measurements of the Z boson-lepton coupling asymmetry parameters Ae, Amu, and Atau with the complete sample of polarized Z bosons collected by the SLD detector at the SLAC Linear Collider. From the left-right production and decay polar angle asymmetries in leptonic Z decays we measure Ae = 0.1544 +- 0.0060, Amu = 0.142 +- 0.015, and Atau = 0.136 +- 0.015. Combined with our left-right asymmetry measured from hadronic decays, we find Ae = 0.1516 +- 0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin**2 theta^{eff}_W = 0.23098 +- 0.00026.

1 data table

No description provided.


A Search for the electric dipole moment of the tau lepton

The ARGUS collaboration Albrecht, H. ; Hamacher, T. ; Hofmann, R.P. ; et al.
Phys.Lett. B485 (2000) 37-44, 2000.
Inspire Record 526643 DOI 10.17182/hepdata.46940

Using the ARGUS detector at the e+e- storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor d_tau of the tau lepton in the production of tau pairs at q^2=100 GeV^2. This is the first direct measurement of this CP violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed tau decay products. No evidence for CP violation was found, and we derive the following results: Re(d_tau)=(1.6+-.9)*10^(-16) ecm and Im(d_tau)=(-0.2+-0.8)*10^(-16) ecm, where statistical and systematic errors have been combined.

1 data table

Electric dipole moment in E(electric charge)*CM units. Systematic and statistical errors are added in quadrature.


Improved measurements of cross-sections and asymmetries at the Z0 resonance

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Nucl.Phys. B418 (1994) 403-427, 1994.
Inspire Record 373114 DOI 10.17182/hepdata.48349
10 data tables

No description provided.

First result corresponds to the total cross section (i.e. S+T channel), while second one corresponds to S-channel only. An acollinearity less that 10 deg.

Forward-backward asymmetry within the polar angular range 44 < THETA < 136 degrees and acollinearity < 10 degrees.. First result corresponds to the total cross section (i.e. S+T channel), while second one corresponds to S-channel only.

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Tests of the standard model and constraints on new physics from measurements of fermion pair production at 183-GeV at LEP

The OPAL collaboration Abbiendi, G. ; Ackerstaff, K. ; Alexander, G. ; et al.
Eur.Phys.J. C6 (1999) 1-18, 1999.
Inspire Record 473699 DOI 10.17182/hepdata.49337

Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward asymmetries for the leptonic final states have also been measured. Cross-sections and asymmetries are also presented for data recorded in 1997 at sqrt(s) = 130 and 136 GeV. The results are used to measure the energy dependence of the electromagnetic coupling constant alpha_em, and to place limits on new physics as described by four-fermion contact interactions or by the exchange of a new heavy particle such as a leptoquark, or of a squark or sneutrino in supersymmetric theories with R-parity violation.

21 data tables

No description provided.

The contribution of interference between initial- and final-state radiationhas been removed.

The contribution of interference between initial- and final-state radiationhas been removed.

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Search for CP violation in Z ---> tau tau

The ALEPH collaboration Buskulic, D. ; Decamp, D. ; Goy, C. ; et al.
Phys.Lett. B297 (1992) 459-468, 1992.
Inspire Record 341557 DOI 10.17182/hepdata.48510
1 data table

No description provided.


Precise measurement of the left-right cross-section asymmetry in Z boson production by e+ e- collisions

The SLD collaboration Schumm, B.A. ;
Nucl.Phys.Proc.Suppl. 40 (1995) 497-503, 1995.
Inspire Record 389176 DOI 10.17182/hepdata.31853
1 data table

R and L refer to Right and Left handed electron beam polarization. ASYM is defined as follows : ASYM = ((SIG(C=L)-SIG(C=R))/(SIG(C=L)+SIG(C=R)).


Measurement of the Michel parameters and the average tau-neutrino helicity from tau decays in e+ e- ---> tau+ tau-

The L3 collaboration Acciarri, M. ; Adam, A. ; Adriani, O. ; et al.
Phys.Lett. B377 (1996) 313-324, 1996.
Inspire Record 418417 DOI 10.17182/hepdata.47587
1 data table

No description provided.


A Precise measurement of the tau polarization and its forward - backward asymmetry at LEP

The OPAL collaboration Alexander, G. ; Allison, John ; Altekamp, N. ; et al.
Z.Phys. C72 (1996) 365-375, 1996.
Inspire Record 421815 DOI 10.17182/hepdata.47776
1 data table

No description provided.


Measurement of the hadronic decay current in tau- --> pi- pi- pi+ tau-neutrino

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.
Z.Phys. C67 (1995) 45-56, 1995.
Inspire Record 393414 DOI 10.17182/hepdata.52012
2 data tables

See paper for definition of four weak decay formfactors : wa, wc, wd, we. For TAU+-.

Here ASYM is parity violating asymmetry parameter gamma_VA = 2g_v*g_A/(g_v **2+g_A**2) (see paper).


A Measurement of the tau leptonic branching fractions

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett. B357 (1995) 715-724, 1995.
Inspire Record 398321 DOI 10.17182/hepdata.48138
3 data tables

Axis error includes +- 0.23/0.23 contribution (Data statistics).

Axis error includes +- 0.19/0.19 contribution (Data statistics).

Combined from the two branching fractions above. E-MU universality assumed.


Measurements of the tau polarization in Z0 decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys. C67 (1995) 183-202, 1995.
Inspire Record 393793 DOI 10.17182/hepdata.47961
10 data tables

Results are for both TAU+ and TAU- decay.

The systematic error contains a systematic error of 0.003 common to all channels.

Errors are statistical only.

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Measurement of the Reactions $e^+ e^- \to \mu^+ \mu^-$ and $e^+ e^- \to \tau^+ \tau^-$ Between $\sqrt{s}=50$-{GeV} and 60.8-{GeV}

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Z.Phys. C48 (1990) 13-22, 1990.
Inspire Record 294672 DOI 10.17182/hepdata.38414
5 data tables

No description provided.

No description provided.

No description provided.

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Measurement of the $Z^0$ line shape parameters and the electroweak couplings of charged leptons

The OPAL collaboration Alexander, G. ; Allison, John ; Allport, P.P. ; et al.
Z.Phys. C52 (1991) 175-208, 1991.
Inspire Record 315269 DOI 10.17182/hepdata.14859
11 data tables

DATA FROM 1989 RUN. The cross section are quoted with their statistical and point-to-point systematic uncertainty of both the multihadron acceptance and the luminosity calculation.

DATA FROM 1990 RUN. The cross section are quoted with their statistical and point-to-point systematic uncertainty of both the multihadron acceptance and the luminosity calculation.

Cross sections corrected for the effects of efficiency and kinematic cuts and background. Data from 1989 run, reanalysed.

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Electroweak studies in e+ e- collisions: 12 < s**(1/2) < 46.78 GeV

The MARK J collaboration Adeva, B. ; Anderhub, H. ; Ansari, S. ; et al.
Phys.Rev. D38 (1988) 2665-2678, 1988.
Inspire Record 274887 DOI 10.17182/hepdata.23272
9 data tables

SIG(QED) = 86.85/S.

No description provided.

No description provided.

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The Production and Decay of Tau Leptons

The Mark-J collaboration Adeva, B. ; Ansari, S. ; Becker, U. ; et al.
Phys.Lett. B179 (1986) 177-182, 1986.
Inspire Record 230298 DOI 10.17182/hepdata.14556
4 data tables

Total cross section calculated from measured channel cross section assuming BR(tau-mu) = 17.6 pct. SIG(Q=MU) is the QED point cross section.

No description provided.

No description provided.

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Measurements of cross-sections and charge asymmetries for $e^+e^- \to \tau^+ \tau^-$ and $e^+e^- \to \mu^+ \mu^-$ for $\sqrt{s}$ from 52 GeV to 57-GeV

The AMY collaboration Bacala, A. ; Malchow, R.L. ; Sparks, K. ; et al.
Phys.Lett. B218 (1989) 112-118, 1989.
Inspire Record 265797 DOI 10.17182/hepdata.51370
11 data tables

Axis error includes +- 5/5 contribution (Included in the quoted errors for the total cross sections. The main contribution to SYS-ERR are the systematic uncertainty in the luminosity measurement and the uncertainty in the computer modeling of the various efficiencies and backgrounds).

Axis error includes +- 5/5 contribution (Included in the quoted errors for the total cross sections. The main contribution to SYS-ERR are the systematic uncertainty in the luminosity measurement and the uncertainty in the computer modeling of the various efficiencies and backgrounds).

No description provided.

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Unique Solution for the Weak Neutral Current Coupling Constants in Purely Leptonic Interactions

The Mark-J collaboration Barber, D.P. ; Becker, U. ; Berghoff, G. ; et al.
Phys.Lett. B95 (1980) 149-153, 1980.
Inspire Record 154136 DOI 10.17182/hepdata.6235
3 data tables

No description provided.

No description provided.

No description provided.


Electroweak Effects in $e^+ e^- \to \tau^+ \tau^-$ at 29-{GeV}

Fernandez, E. ; Ford, William T. ; Qi, N. ; et al.
Phys.Rev.Lett. 54 (1985) 1620, 1985.
Inspire Record 207555 DOI 10.17182/hepdata.3267
4 data tables

Data fully corrected up to O(ALPHA**3) radiative effects. Data requested from authors.

Data extrapolated to full acceptance.

No description provided.

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Measurement of the Polarization of $\tau$ Leptons Produced in $e^+ e^-$ Annihilation at $\sqrt{s}=29$-{GeV}

Ford, William T. ; Qi, N. ; Read, Alexander L. ; et al.
Phys.Rev. D36 (1987) 1971, 1987.
Inspire Record 245571 DOI 10.17182/hepdata.23349
1 data table

No description provided.


Weak Neutral Currents in e+ e- Collisions at s**(1/2)=29-GeV

Levi, M.E. ; Blocker, C.A. ; Strait, J. ; et al.
Phys.Rev.Lett. 51 (1983) 1941, 1983.
Inspire Record 191845 DOI 10.17182/hepdata.3281
8 data tables

Numerical values supplied by M.Levi.

Data requested from authors.

Extrapolated to full angular range.

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Measurement of $e^+ e^- \to \tau^+ \tau^-$ at High-energy and Properties of the $\tau$ Lepton

The CELLO collaboration Behrend, H.J. ; Chen, C. ; Fenner, H. ; et al.
Phys.Lett. B114 (1982) 282-286, 1982.
Inspire Record 177224 DOI 10.17182/hepdata.6667
4 data tables

No description provided.

No description provided.

Forward-backward asymmetry based on 1 + (cos(theta))**2 + bcos(theta) fit for angular distribution.

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Charge Asymmetry and Weak Interaction Effects in $e^+ e^- \to \mu^+ \mu^-$ and $e^+ e^- \to \tau^+ \tau^-$

The TASSO collaboration Brandelik, R. ; Braunschweig, W. ; Gather, K. ; et al.
Phys.Lett. B110 (1982) 173-180, 1982.
Inspire Record 176719 DOI 10.17182/hepdata.6699
7 data tables

No description provided.

No description provided.

No description provided.

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