Lindgren, M.
ALPHAS
Max results
Sort by Reverse order

Showing 10 of 96 results

MEASUREMENT OF alpha-s FROM HADRON JETS IN e+ e- ANNIHILATION AT S**(1/2) OF 29-GeV

Ford, William T. ; Qi, N. ; Read, Alexander L. ; et al.
Phys.Rev.D 40 (1989) 1385, 1989.
Inspire Record 276788 DOI 10.17182/hepdata.23112

A study of the lateral development of jets of hadrons produced in electron-positron annihilation has been used to determine the strong coupling constant αs. Data were obtained with the MAC detector at the SLAC e+e− storage ring PEP at s=29 GeV. Based on the parton calculations of Gottschalk and Shatz, a value for αs of 0.133±0.005(stat)±0.009(syst) has been determined for string fragmentation, and 0.112±0.008(stat)±0.007(syst) for an independent-jet model.

2 data tables
Table 1

JET FRACTION MEASURED. FIT ACCORDING TO:. T.D. GOTTSCHALK AND M.P.SCHATZ CALT-68-1172 (1985).

Table 2

JET FRACTION MEASURED. FIT ACCORDING TO INDEPENTENT JET MODEL.


rivet Analysis
Determination of $\alpha^- s$ From a Measurement of the Direct Photon Spectrum in $\Upsilon$ (1s) Decays

The ARGUS collaboration Albrecht, H. ; Andam, A.A. ; Binder, U. ; et al.
Phys.Lett.B 199 (1987) 291-296, 1987.
Inspire Record 248655 DOI 10.17182/hepdata.30061

Using the ARGUS detector at the DORIS II e + e − storage ring we have measured direct photons from the decay ???(1 S )→ γgg . The ratio R γ = Γ (???(1S)→ γgg )/ Γ (???(1S)→ ggg )=(3.00±0.13±0.18)% has been determined, from which we deduce values of the strong coupling constant α s =0.225±0.011±0.019 and the QCD scale parameter Λ MS =115±17±28 MeV defined in the modified minimal-subtraction scheme. The shape of the measured spectrum clearly rules out the predictions of the lowest order QCD calculations.

1 data table
Table 1

No description provided.


rivet Analysis
A Study of Energy-energy Correlations Between 12-{GeV} and 46.8-{GeV} {CM} Energies

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 36 (1987) 349-361, 1987.
Inspire Record 248660 DOI 10.17182/hepdata.1698

We present data on energy-energy correlations (EEC) and their related asymmetry (AEEC) ine+e− annihilation in the centre of mass energy range 12

10 data tables
Table 1

Correlation function binned in cos(chi).

Table 2

Correlation function binned in cos(chi).

Table 3

Correlation function binned in cos(chi).

More…

rivet Analysis
Determination of alpha-s and sin**2theta(w) from Measurements of the Total Hadronic Cross-Section in e+ e- Annihilation

The CELLO collaboration Behrend, H.J. ; Burger, J. ; Criegee, L. ; et al.
Phys.Lett.B 183 (1987) 400-411, 1987.
Inspire Record 236981 DOI 10.17182/hepdata.30231

We have measured the total normalized cross section R for the process e + e − → hadrons at centre-of-mass energies between 14.0 and 46.8 GeV based on an integrated luminosity of 60.3 pb −1 . The data are well described by the standard SU(3) c ⊗SU(2) L ⊗U(1) model with the production of the five known quarks. No open production of a sixth quark with charge 2/3 or 1/3 occurs below a centre-of-mass energy of 46.6 or 46.3 GeV, respectively. A fitting procedure which takes the correlations between measurements into account was used to determine the electroweak mixing angle sin 2 θ w and the strong coupling constant α s ( S ) in second-order QCD. We applied this procedure to the CELLO data and in addition included the data from other experiments at PETRA and PEP. Both fits give consistent results. The fit to the combined data yields α s (34 2 GeV 2 ) = 0.165±0.030, and sin 2 θ w = 0.236±0.020. Fixing sin 2 θ w at the world average value of 0.23 yields α s (34 2 GeV 2 ) = 0.169±0.025.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Measurement of the Branching Ratio for $\Upsilon^\prime$-prime $\to \mu \mu$

Kaarsberg, T. ; Lee-Franzini, Juliet ; Lovelock, D.M.J. ; et al.
Phys.Rev.D 35 (1987) 2265, 1987.
Inspire Record 230842 DOI 10.17182/hepdata.23382

Using the CUSB-II detector at the Cornell Electron Storage Ring, we have measured Bμμ, the branching fraction into muons, of the Υ’’ meson. We find Bμμ(Υ’’)=(1.53±0.33±0.21)%, from which the Υ’’ total decay width is 25.5±5.0 keV. From this result we obtain αs=0.170−0.012+0.015, ΛMS¯=148−39+56 MeV. (MS¯ denotes the modified minimal-subtraction scheme).

1 data table
Table 1

No description provided.


A Measurement of the Strong Coupling Constant $\alpha^- s$ to Complete Second Order

The Mark-J collaboration Adeva, B. ; Anderhub, H. ; Ansari, S. ; et al.
Phys.Lett.B 180 (1986) 181-184, 1986.
Inspire Record 231302 DOI 10.17182/hepdata.6535

The strong interaction coupling constant α s has been measured with a new method, the planar triple energy correlation in the reaction e + e - → hadrons at center-of-mass energies ranging from 14 GeV to 46.78 GeV. A complete second-order perturbative QCD calculation was used. Λ MS = 110 ± 30 −55 +70 MeV is found.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


A Measurement of Strong Coupling Constant $\alpha_s$ to Second Order for 14-{GeV} $\le \sqrt{s} \le$ 46.78-{GeV}

The MARK-J collaboration Adeva, B. ; Becker, U. ; Becker-Szendy, R. ; et al.
Phys.Rev.Lett. 54 (1985) 1750, 1985.
Inspire Record 208007 DOI 10.17182/hepdata.20386

Using the Mark-J detector at the high-energy e+e− collider PETRA, we compare the data from hadron production with the complete second-order QCD calculation over the energy region 22 to 46.78 GeV. We determine the QCD parameter Λ=100±30−45+60 MeV which yields the strong-coupling constant αs=0.12±0.02 for s=44 GeV.

2 data tables
Table 1

No description provided.

Table 2

Axis error includes +- 0.0/0.0 contribution (DUE TO FRAGMENTATION MODEL).


rivet Analysis
Precision Measurement of the Total Cross-section for $e^+ e^- \to$ Hadrons at a Center-of-mass Energy of 29-{GeV}

Fernandez, E. ; Ford, William T. ; Qi, N. ; et al.
Phys.Rev.D 31 (1985) 1537, 1985.
Inspire Record 206052 DOI 10.17182/hepdata.4048

We report a high-precision measurement of the ratio R of the total cross section for e+e−→hadrons to that for e+e−→μ+μ−, at a center-of-mass energy of 29.0 GeV using the MAC detector. The result is R=3.96±0.09. This value of R is used to determine a value of the strong coupling constant αs of 0.23±0.06, nearly independent of fragmentation models. Two different analysis methods having quite different event-selection criteria have been used and the results are in agreement. Particular attention has been given to the study of systematic errors. New higher-order QED calculations are used for the luminosity determination and the acceptance for hadrons.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Determination of $\alpha_s$ in First and Second Order {QCD} From $e^+ e^-$ Annihilation Into Hadrons

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Kirschfink, F.J. ; et al.
Z.Phys.C 26 (1984) 157, 1984.
Inspire Record 203143 DOI 10.17182/hepdata.16210

None

1 data table
Table 1

No description provided.


rivet Analysis
Measurements of Energy Correlations in $e^+ e^- \to$ Hadrons

The JADE collaboration Bartel, W. ; Becker, L. ; Bowdery, C. ; et al.
Z.Phys.C 25 (1984) 231, 1984.
Inspire Record 202784 DOI 10.17182/hepdata.1998

Energy-energy-correlations (EEC) have been measured with the JADE detector at c.m. energies of 14 GeV, 22 GeV and in the region 29 GeV

3 data tables
Table 1

TABLES GIVEN HERE CONTAIN SELF CORRELATION. THIS IS SUBTRACTED IN THE FIGURE.

Table 2

VALUE OF ASSYMETRY IN CORRELATIONS.

Table 3

No description provided.