Baer, H.W.
R measurement
Max results
Sort by Reverse order

Showing 10 of 18 results

rivet Analysis
Measurements of the Cross Section for e+e- -> hadrons at Center-of-Mass Energies from 2 to 5 GeV

The BES collaboration Bai, J.Z. ; Ban, Y. ; Bian, J.G. ; et al.
Phys.Rev.Lett. 88 (2002) 101802, 2002.
Inspire Record 552757 DOI 10.17182/hepdata.41990

We report values of $R = \sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$ for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

1 data table
Table 1

Measured values of R.


rivet Analysis
Measurement of the Total Cross Section for Hadronic Production by e+e- Annihilation at Energies between 2.6-5 Gev

The BES collaboration Bai, J.Z. ; Ban, Y. ; Bian, J.G. ; et al.
Phys.Rev.Lett. 84 (2000) 594-597, 2000.
Inspire Record 505323 DOI 10.17182/hepdata.41611

Using the upgraded Beijing Spectrometer (BESII), we have measured the total cross section for $e^+e^-$ annihilation into hadronic final states at center-of-mass energies of 2.6, 3.2, 3.4, 3.55, 4.6 and 5.0 GeV. Values of $R$, $\sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$, are determined.

1 data table
Table 1

Data are corrected for acceptance and radiative effects.


A MEASUREMENT OF e+ e- ---> b anti-b FORWARD - BACKWARD CHARGE ASYMMETRY BETWEEN s**(1/2) = 52-GeV AND 57-GeV

The AMY collaboration Sagawa, H. ; Lim, J. ; Abe, K. ; et al.
Phys.Rev.Lett. 63 (1989) 2341, 1989.
Inspire Record 279824 DOI 10.17182/hepdata.19996

Using 123 multihadronic inclusive muon-production e+e− annihilation events at an average c.m. energy of 55.2 GeV, we extracted the forward-backward charge asymmetry of the e+e−→bb¯ process and the R ratio for bb¯ production. We used an analysis method in which the behavior of the c quark and lighter quarks is assumed, with only that of the b quark left indeterminate. The results, Ab=-0.72±0.28(stat)±0.13(syst) and Rb=0.57±0.16±0.10, are consistent with the standard model.

2 data tables
Table 1

Asymmetry in BOTTOM quark production.

Table 2

Ratio of BOTTOM quark production to total hadron cross section (R value).


rivet Analysis
MEASUREMENTS OF R FOR e+ e- ANNIHILATION AT TRISTAN

The AMY collaboration Kumita, T. ; Sagawa, H. ; Auchincloss, Priscilla S. ; et al.
Phys.Rev.D 42 (1990) 1339-1349, 1990.
Inspire Record 294525 DOI 10.17182/hepdata.22908

The ratio R of the total cross section for e+e− annihilation into hadrons to the lowest-order QED cross section for e+e−→μ+μ− has been measured for center-of-mass energies ranging from 50 to 61.4 GeV. If we allow for an overall shift of —4.9%, about 1.5 times our estimated normalization error, the results are consistent with the standard-model predictions.

1 data table
Table 1

Error quoted contains point-to-point systematics. There is also an additional 3.2 pct systematic error.


MEASUREMENTS OF THE e+ e- TOTAL HADRONIC CROSS-SECTION AND A DETERMINATION OF M(Z) AND LAMBDA (MS)

The AMY collaboration Mori, T. ; Nozaki, T. ; Blanis, D. ; et al.
Phys.Lett.B 218 (1989) 499-507, 1989.
Inspire Record 276653 DOI 10.17182/hepdata.29847

The total cross section for e + e − annihilation into hadrons has been measured for CM energies ranging from 50 to 57 GeV. We fit the predictions of the standard model to these measurements and those at lower energies. The mass of the Z 0 boson, M Z , and the QCD scale parameter, Λ MS , are derived from the fit. The results are M Z =88.6 −1.8 +2.0 GeV/ c 2 , and Λ MS =0.15 −0.11 +0.16 GeV .

1 data table
Table 1

No description provided.


Experimental Study of Electroweak Parameters at {PETRA} Energies (12-{GeV} $< E_{CMS} <$ 36.7-{GeV})

The MARK-J collaboration Barber, D.P. ; Becker, U. ; Bei, G.D. ; et al.
Phys.Rev.Lett. 46 (1981) 1663, 1981.
Inspire Record 164675 DOI 10.17182/hepdata.3303

We have performed a high-statistics measurement of Bhabha scattering and of the production of hadrons in electron-positron annihilation at PETRA energies (12 GeV<~s<~36.7 GeV). Combining the results with measurements of μ+μ− and τ+τ− production enables us to compare our results with electroweak theory. We find sin2θw=0.27±0.08. This is in good agreement with the value obtained from neutrino experiments which were carried out in entirely different kinematic regions.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

ASYMMETRY WAS USED.

More…

rivet Analysis
Determination of $\gamma (e e$) of the $\Upsilon$ (1s) and $\Upsilon$ (2s) Resonances and Measurement of R at $W=9$.39-{GeV}

The Crystal Ball collaboration Jakubowski, Z. ; Antreasyan, D. ; Bartels, H.W. ; et al.
Z.Phys.C 40 (1988) 49, 1988.
Inspire Record 261078 DOI 10.17182/hepdata.15560

Using the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widthsГeeof the Υ(1S) and Υ(2S) reson

1 data table
Table 1

No description provided.


Measurements of r and a Search for Heavy Quark Production in e+ e- Annihilation at s**(1/2) = 50-GeV and 52-GeV

The AMY collaboration Sagawa, H. ; Mori, T. ; Abe, K. ; et al.
Phys.Rev.Lett. 60 (1988) 93, 1988.
Inspire Record 251270 DOI 10.17182/hepdata.20143

The ratio R of the cross section for e+e− annihilation into hadronic final states to the QED cross section for muon-pair production is measured to be 4.34±0.45±0.30 and 4.23±0.20±0.21 at c.m. energies of 50 and 52 GeV, respectively. From these values of R and an analysis of the event shapes we deduce a 95%-confidence-level upper limit for the production rate of new heavy charge +23e or −13e quarks to be 0.19 units of R.

1 data table
Table 1

No description provided.


rivet Analysis
Study of Hadron and Inclusive Muon Production From Electron Positron Annihilation at 39.79-{GeV} $\le \sqrt{s} \le$ 46.78-{GeV}

The Mark-J collaboration Adeva, B. ; Ansari, S. ; Becker, U. ; et al.
Phys.Rev.D 34 (1986) 681-691, 1986.
Inspire Record 230297 DOI 10.17182/hepdata.23423

We use the reaction e+e−→hadrons, in the Mark J detector at the DESY electron-positron collider PETRA, to determine the hadronic cross section up to 46.78 GeV. The production of a top quark with a charge equal to (2/3) is excluded up to 46.6 GeV with 95% C.L. The observed rise in the cross section at higher energies is consistent with the electroweak prediction for a Z0 mass of 93 GeV. We describe some unusual muon inclusive events.

3 data tables
Table 1

Errors are statistical only.

Table 2

Energy scan of R.

Table 3

Inclusive muon cross section.


rivet Analysis
A Summary of Recent Experimental Results From Mark-$J$: High-energy $e^+ e^-$ Collisions at {PETRA}

The Mark-J collaboration Adeva, B. ; Barber, D.P. ; Becker, U. ; et al.
Phys.Rept. 109 (1984) 131, 1984.
Inspire Record 196567 DOI 10.17182/hepdata.30997

None

6 data tables
Table 1

DATA ARE CORRECTED FOR TWO-PHOTON AND TAU PRODUCTION EFFECTS, ACCEPTANCE AND QED RADIATIVE EFFECTS UP TO ORDER ALPHA**3. THERE IS ALSO A 6 PCT NORMALISATION ERROR NOT INCLUDED. THE OVERALL AVERAGE VALUE OF R FROM THIS DATA IS 3.88 +- 0.04 +- 0.22.

Table 2

No description provided.

Table 3

SEE PRL 55, 665 FOR MOST RECENT VALUES OF THE MU+ MU- CROSS SECTIONS.

More…