The production rates of D*+-, Ds*+-, D+-, D0 / D0bar, Ds+, and Lambda_c in Z to ccbar decays are measured using the LEP I data sample recorded by the ALEPH detector. The fractional energy spectrum of the D*+- is well described as the sum of three contributions: charm hadronisation, b hadron decays and gluon splitting into a pair of heavy quarks. The probability for a c quark to hadronise into a D*+ is found to be f(c to D*+) = 0.233 +- 0.010 (stat.) +- 0.011 (syst.). The average fraction of the beam energy carried by D*+- mesons in Z to cc events is measured to be < X_E (D*+-) >_cc = 0.4878 +- 0.0046 (stat.) +- 0.0061 (syst.). The D*+- energy and the hemisphere mass imbalance distributions are simultaneously used to measure the fraction of hadronic Z decays in which a gluon splits to a cc pair: n_{gluon to cc} = (3.23 +- 0.48 (stat.) +- 0.53 (syst.) %. The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be P_V = 0.595 +- 0.045. The fractional decay width of the Z into cc pairs is determined from the sum of the production rates for various weakly decaying charmed states to be Rc = 0.1738 +- 0.0047 (stat.) +- 0.0116 (syst.).
The differential D*+- production rate. Statistical errors only.
The multiplicity of D*+- events using a MC shape to do the very small extrapolation over the entire X range.
Fraction of hadronic Z0 decays into charm quark pairs summing all the contributions of the fundamental charmed states and including a contribution from baryons not decaying to LAMBDA/C+. The second DSYS error is due to the uncertainty in the branching ratio.
The production rates and the inclusive cross sections of the isovector meson${\rm \pi^0}$, the isoscalar mesons$\eta$and
Inclusive cross section for PI0 production in hadronic events.
Inclusive cross section for ETA production in hadronic events.
Inclusive cross section for ETAPRIME production in hadronic events.
New results of the neutron-proton spin-dependent total cross section difference$\Delta\sigma_L(np)$at the neutron beam kinetic energies 1.59, 1.79 and 2.20 GeV ar
Final results from the np data.
Values of the cross section difference at I=0 deduced by combining these npdata with pure pp (I=1) data from other experiments.
A precise measurement of the strange quark forward-backward asymmetry used 3.2M multihadronic events around the Z$^0$peak collected by the DELPHI experiment from 1
No description provided.
Parity violating coupling, COUPLING(NAME=A_S) = (2*V_S*A_S)/(V_S**2+A_S**2).
The inclusive charm production rate in W decays is measured from a study of the properties of final state particles. The sample of W pairs is selected from 67.7 pb −1 collected by ALEPH in 1996 and 1997 at centre-of-mass energies near 172 and 183 GeV in the channels W + W − →4q and W + W − →ℓνq q ̄ . The branching fraction of hadronic W decays to a final state containing a c quark, R W c = Γ(W→cX)/Γ(W→hadrons), is measured to be 0.51±0.05 stat ±0.03 syst . This allows a direct determination of the CKM matrix element |V cs |=1.00±0.11 stat ±0.07 syst .
VCS is the CKM matrix element.
In the experiment with the SND detector at VEPP-2M e^+e^- collider the process $e^+e^-\to\pi^+\pi^-\pi^0$ was studied in the energy range 2E_0 from 1.04 to 1.38 GeV. A broad peak was observed with the visible mass $M_{vis}=1220\pm 20$ MeV and cross section in the maximum $\sigma_0\simeq 4$ nb. The peak can be interpreted as a $\omega$-like resonance $\omega (1200)$.
The total cross section for E+ E- --> PI+ PI- PI0 after correction for efficiency and radiative effects.
The ee -> ZZ cross section at sqrt(s)=182.7 and 188.6 GeV has been measured using the ALEPH detector. The analysis covers all of the visible ZZ final states and yields cross section measurements of sigma_ZZ(182.7 GeV) = 0.11 +- (0.16,0.11) (stat.) +- 0.04 (syst.) pb and sigma_ZZ(188.6 GeV) = 0.67 +- 0.13 (stat.) +- 0.04 (syst.) pb consistent with the Standard Model expectations.
The combined cross sections for the 2Z0 (NC2) fixed state.
The fragmentation functions of quarks and gluons are measured in various three-jet topologies in Z decays from the full data set collected with the Delphi detector at the Z resonance between 1992 and
Charged hadron XE(=Z) distributions. Durham algorithm. XISTAR is peak position in XI=LOG(-XE) distribution.
Charged hadron XE(=Z) distributions. Durham algorithm. XISTAR is peak position in XI=LOG(-XE) distribution.
Charged hadron XE(=Z) distributions. Durham algorithm. XISTAR is peak position in XI=LOG(-XE) distribution.
The$\tau$polarisation has been studied with the${\rm e^+e^-}\to \tau^+\tau^-$data collected by the DELPHI detector at LEP in
The errors are statistical and systematic combined in quadrature.
No description provided.
The branching ratio for the leptonic decay of charged B mesons ( B − →τ − ν ̄ τ ) has been measured using selected leptonic τ − →ℓ − ν τ ν ̄ ℓ and hadronic τ − → ν τ X decays in Z → b b ̄ decays recorded by DELPHI at LEP1 in 1992–1995. The result, BR ( B − →τ − ν ̄ τ )<1.1×10 −3 at the 90% confidence level, is consistent with standard model expectations and puts a constraint on the ratio tan β / M H ± <0.46 (GeV/ c 2 ) −1 in the framework of models with two Higgs doublets (type II Higgs doublet model). From the missing energy distribution in Z → b b ̄ decays without identified leptons, the b →τ ν ̄ τ X branching ratio has been measured in the hadronic channel τ → ν τ X′. The result, BR ( b →τ ν ̄ τ X )=(2.19±0.24 ( stat )±0.39 ( syst ))% , is consistent with the Standard Model prediction and with previous experimental measurements.
TAN(BETA) is the two-Higgs-doublet model parameter, while M_H is the mass of charged Higgs.
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