Pairs of τ leptons produced at s=3.77 GeV have been studied in eμ, ee, and μμ final states. The leptonic branching ratios have been measured to be B(τ→eνν)=(18.2±0.7±0.5)% and B(τ→μνν)=(18.0±1.0±0.6)%. Limits have been set for the two-body decays τ→eG and τ→μG, where G is a light Goldstone boson.
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The production of the hypertriton nuclei $^{3}_{\Lambda}\mathrm H$ and $^{3}_{\bar{\Lambda}} \overline{\mathrm H}$ has been measured for the first time in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with the ALICE experiment at LHC energies. The total yield, d$N$/d$y$ $\times \mathrm{B.R.}_{\left( ^{3}_{\Lambda}\mathrm H \rightarrow ^{3}\mathrm{He},\pi^{-} \right)} = \left( 3.86 \pm 0.77 (\mathrm{stat.}) \pm 0.68 (\mathrm{syst.})\right) \times 10^{-5}$ in the 0-10% most central collisions, is consistent with the predictions from a statistical thermal model using the same temperature as for the light hadrons. The coalescence parameter $B_3$ shows a dependence on the transverse momentum, similar to the $B_2$ of deuterons and the $B_3$ of $^{3}\mathrm{He}$ nuclei. The ratio of yields $S_3$ = $^{3}_{\Lambda}\mathrm H$/($^{3}\mathrm{He}$ $\times \Lambda/\mathrm{p}$) was measured to be $S_3$ = 0.60 $\pm$ 0.13 (stat.) $\pm$ 0.21 (syst.) in 0-10% centrality events; this value is compared to different theoretical models. The measured $S_3$ is fully compatible with thermal model predictions. The measured $^{3}_{\Lambda}\mathrm H$ lifetime, $ \tau = 181^{+54}_{-39} (\mathrm{stat.}) \pm 33 (\mathrm{syst.})\ \mathrm{ps}$ is compatible within 1$\sigma$ with the world average value.
(Hypertriton + Anti-Hypertriton)dN/d(ct) distribution.
Hypertriton and Anti-hypertriton $p_{\rm T}$ spectra x B.R.
$B_2$ as a function of $p_{\rm T}$/A for Hypertriton.
The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlatio
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.
A measurement of the cross section of the charge-exchange reaction pp→ Δ ++ (1232)n at √ s = 23, 31 and 45 GeV at the CERN-ISR is reported. The energy dependence continues to follow a power law p lab − n with n = 1.94 ± 0.03 indicating dominance of one-pion exchange at the lowest ISR energy; there is some evidence for deviation from this at the higher ISR energies.
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The strong coupling constant αs has been determined from a study of the reaction p¯p→W±X, W→eν at s of 630 GeV in the UA1 experiment at CERN. The measurement is based upon a study of jet production in association with W bosons. The result obtained is αs(MW2)=0.127±0.026(stat)±0.034(syst).
Systematic error not given.
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Results from a partial wave analysis of theKππ system produced in the hypercharge exchange reaction π−p→(K+π−π0)Λ at 3.95 GeV/c are presented. SignificantQ1 production is observed but no evidence is found forQ2 production thus confirming the results obtained in a previous decay Dalitz plot analysis of the same reaction. The relative phase behaviour of the 1+(Kϱ) partial waves obtained with the present analysis provides additional confirmation of the resonance interpretation of theQ1 enhancement. Information is also obtained about its production properties and the role played by the Λ polarization in the hypercharge exchange reaction. This is compared with the results obtained in the reactionK−p→(π+π−π0)Λ at 4 GeV/c.
LAMBDA POLARIZATION CALCULATED AS AVERAGE POLARIZATION OF ALL 1 + (K RHO0) PARTIAL WAVES IN THE QLOW(1240) REGION.
SPIN PARITY CONTENT OF (K PI PI) SYSTEM.
CONTRIBUTION TO THE TOTAL JP=1+ INTENSITY FROM THE K* AND RHO ISOBARS.
The reaction π − p → K + K − π − p at 16 GeV/ c was studied in the CERN OMEGA spectrometer and a partial-wave analysis (PWA) of the low-mass (K + K − π − ) system (1.3–2.0 GeV) was performed. Only states in the unnatural spin-parity series produced by natural parity exchange are important and they approximately conserve t -channel helicity. The 1 + S K ∗ K wave dominates the low-mass (K + K − π − ) region. We observe an enhancement in 2 − P K ∗ K wave at a mass of 1.7 GeV, consistent with the decay of the A 3 resonance.
TOTAL ACCEPTANCE CORRECTED CROSS SECTION.
ACCEPTANCE CORRECTED.
MOST IMPORTANT CONTRIBUTING STATES CORRECTED FOR ACCEPTANCE.
In this paper an investigation of the production of D ∗ ± mesons produced in e + e − collisions at energies around the Z 0 pole is presented. Based on 115 D ∗ ± mesons with x D∗ 2E D ∗ /E cm > 0.2 the properties of D ∗ mesons produced in the reaction Z 0 → c c are studied. Fixing the yield and the fragmentation function of bottom quarks to the values obtained at LEP using lepton tags, and average energy fraction of the D ∗ ± mesons from primary charmed quarks of 〈x c → D ∗ 〉 = 0.52 ± 0.03 +- 0.01 is found and Γ z 0 →c c = (323 ± 61 ± 35) MeV is determined. The first error is the combined statistical and systematic error from this experiment, and the second the total error from other sources.
FD denotes the fraction of D* mesons from primary charmed quarks, derived from the fit (see text).
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We have studied inclusive KS, Λ, and Λ¯ photoproduction over the ranges 40<Eγ<170 GeV and forward produced mass 2<MF<10 GeV. We observe equal Λ and Λ¯ production rates and spectra as expected in a diffractive process where the target proton remains unaltered. We show that the fraction of hadronic events with a strange particle produced in events with forward mass MF agrees well with the same measurement in e+e− annihilation at a center-of-mass energy Ec.m.=MF. The x=2PMF distributions of these three particles in the forward-mass rest frame are compared with theoretical predictions.
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292+-7 MUB - CORRECTED VALUE FOR FIRST REACTION (SLOW PROTONS). M(P 4PI) <= 3.5 GEV FOR REACTIONS WITH FOUR PIONS.
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