Augustin, J.E.
E+ E- Scattering
Max results
Sort by Reverse order

Showing 10 of 369 results

Date

A Study of b quark fragmentation into B0 and B+ mesons at LEP

The OPAL collaboration Alexander, G. ; Allison, J. ; Altekamp, N. ; et al.
Phys.Lett.B 364 (1995) 93-106, 1995.
Inspire Record 400812 DOI 10.17182/hepdata.48093

A study of b quark fragmentation at LEP is presented using a sample of semileptonic B decays containing a fully reconstructed charm meson. The data are compared to several theoretical models for heavy quark fragmentation; the free parameters in these models are fitted and the sensitivity of the model parameters to the rate of P-wave B meson production is studied. The mean scaled energy fraction of B 0 and B + mesons has been determined to be < x E > = 0.695 ± 0.006 ± 0.003 ± 0.007, where the errors are statistical, systematic and model dependence respectively. This result is consistent with previous, less direct measurements from inclusive leptonic B decays. Also presented is a model independent fit to the shape of the energy distribution of weakly decaying B mesons at LEP.

1 data table
Table 1

No description provided.


rivet Analysis
Observation of a narrow state decaying into Xi(c)+ pi-

The CLEO collaboration Avery, P. ; Freyberger, A. ; Lingel, K. ; et al.
Phys.Rev.Lett. 75 (1995) 4364-4368, 1995.
Inspire Record 397770 DOI 10.17182/hepdata.47270

Using data recorded by the CLEO-II detector at CESR, we report the first observation of a narrow state decaying into $\Xi_c~+\pi~-$. The state has mass difference $M(\Xi_c~+\pi~-)-M(\Xi_c~+)$ of $178.2\pm0.5\pm1.0$ $\rm{MeV/c~2}$, and a width of $&lt;5.5$ $\rm{MeV/c~2}$ (90\% confidence level limit). The most likely explanation of this new state is that it is the $J=\32$ spin excitation of the $\Xi_c~0$ charmed baryon.

1 data table
Table 1

No description provided.


Study of prompt photon production in hadronic Z0 decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys.C 69 (1995) 1-14, 1995.
Inspire Record 397391 DOI 10.17182/hepdata.48136

None

3 data tables
Table 1

Rates for gamma + 1 jet.

Table 2

Rates for gamma + 2 jet.

Table 3

Rates for gamma + 3 jet.


A Measurement of the tau leptonic branching fractions

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 357 (1995) 715-724, 1995.
Inspire Record 398321 DOI 10.17182/hepdata.48138

A sample of 25000 Z 0 → τ + τ − events collected by the DELPHI experiment at LEP in 1991 and 1992 is used to measure the leptonic branching fractions of the τ lepton. The results are B(τ → eν ν ) = (17.51 ± 0.39) % and B(τ → μν ν ) = (17.02 ± 0.31) %. The ratio of the muon and electron couplings to the weak charged current is measured to be g μ g e = 1.000 ± 0.013 , satisfying e-μ universality. The leptonic branching fraction corrected to the value for a massless lepton, assuming e-μ universality, is found to be B(τ → lν ν ) = (17.50 ± 0.25) %.

3 data tables
Table 1

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

Table 2

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

Table 3

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


rivet Analysis
Delta++ production in hadronic Z0 decays

The OPAL collaboration Alexander, G. ; Allison, John ; Altekamp, N. ; et al.
Phys.Lett.B 358 (1995) 162-172, 1995.
Inspire Record 398320 DOI 10.17182/hepdata.48153

The production of Δ ++ baryons has been measured using 3.5 million hadronic Z 0 decays collected with the OPAL detector at LEP. The production rate and fragmentation function are presented. A total of 0.22 ± 0.04 ± 0.04 Δ ++ + ( Δ ) −− per hadronic Z 0 decay is observed. The fragmentation function is found to be softer than that predicted by the JETSET and HERWIG Monte Carlo event generators. With this measurement of Δ ++ production, at least one baryon of each strangeness level in the lightest baryon decuplet has now been measured at LEP.

1 data table
Table 1

No description provided.


A Measurement of the photon structure function F2(gamma) at an average Q**2 of 12-GeV**2/c**4

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys.C 69 (1996) 223-234, 1996.
Inspire Record 396884 DOI 10.17182/hepdata.47867

None

2 data tables
Table 1

No description provided.

Table 2

Low x domain.


Search for exclusive charmless B meson decays with the DELPHI detector at LEP

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 357 (1995) 255-266, 1995.
Inspire Record 397145 DOI 10.17182/hepdata.52353

Charmless hadronic decays of beauty mesons have been searched for using the data collected with the DELPHI detector at the LEP collider. Several two, three and four-body decay modes have been investigated. Particle identification was used to distinguish the final states with protons, kaons and pions. Three candidate events selected in two-body decay modes are interpreted as evidence for charmless B decays. No excess has been found in higher multiplicity modes and improved upper limits for some of the branching ratios are given.

3 data tables
Table 1

Two body decay modes. Upper limits at 90% CL. In computing of limits the fractions of B/(d,u)(0,-) and B/S0 mesons were assumed to be 0.39 and 0.12 respectively. Limits are given for the weighted average of the decay rates of the two neutral B mesons.

Table 2

Three body decay modes. Upper limits at 90% CL.

Table 3

Four body decay modes. Upper limits at 90% CL.


Measurement of the average b baryon lifetime and the product branching ratio f (b --> Lambda(b)) x BR (Lambda(b) --> Lambda lepton- anti-neutrino X)

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.
Z.Phys.C 69 (1996) 195-214, 1996.
Inspire Record 397395 DOI 10.17182/hepdata.51966

None

1 data table
Table 1

Charged conjugate state is assumed.


A Model independent measurement of quark and gluon jet properties and differences

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.
Z.Phys.C 68 (1995) 179-202, 1995.
Inspire Record 396179 DOI 10.17182/hepdata.47862

None

3 data tables
Table 1

THETA is the angle between hadron and jet's axis. CONST is the parameter used in jet's definition (see text).

Table 2

CONST is the parameter used in jet's definition (see text).

Table 3

CONST is the parameter used in jet's definition (see text).


Measurement of the longitudinal, transverse and asymmetry fragmentation functions at LEP

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.
Z.Phys.C 68 (1995) 203-214, 1995.
Inspire Record 395450 DOI 10.17182/hepdata.48040

The fragmentation function for the process e+e−→h+X, whereh represents a hadron, may be decomposed into transverse, longitudinal and asymmetric contributions by analysis of the distribution of polar production angles. A number of new tests of QCD have been proposed using these fragmentation functions, but so far no data have been published on the separate components. We have performed such a separation using data on charged particles from hadronic Z0 decays atOpal, and have compared the results with the predictions of QCD. By integrating the fragmentation functions, we determine the average charged particle multiplicity to be\(\overline {n_{ch} }= 21.05 \pm 0.20\). The longitudinal to total cross-section ratio is determined to be σL/σtot=0.057±0.005. From the longitudinal fragmentation function we are able to extract the gluon fragmentation function. The connection between the asymmetry fragmentation function and electroweak asymmetrics is discussed.

4 data tables
Table 1

Transverse component of the fragmentation function.

Table 2

Longitudinal component of the fragmentation function.

Table 3

Asymmetry component of the fragmentation function.

More…