Measurement of W-pair production in $e^{+}e^{-}$ collisions at centre-of-mass energies from 183 to 209 GeV

The W + W- production cross section is measured from a data sample corresponding to a total integrated luminosity of 683 pb-1, collected by the ALEPH experiment at LEP at centre-of-mass energies from 183 to 209 GeV. Individual cross sections for the different topologies arising from W decays into leptons or hadrons, as well as the total W-pair cross section are given at eight centre-of-mass energies. The results are found to be in agreement with recently developed Standard Model calculations at the one percent level. The hadronic branching fraction of the W boson is measured to be B(W→qq¯) = 67.13 ± 0.37(stat.) ± 0.15(syst.)%, from which the CKM matrix element |\ensuremathVcs| is determined…

Search for γγ→ηb in e+e− collisions at LEP 2

A search for the pseudoscalar meson eta_b is performed in two-photon interactions at LEP~2 with an integrated luminosity of 699 pb^-1 collected at e+e- centre-of-mass energies from 181 GeV to 209 GeV. One candidate event is found in the six-charged-particle final state and none in the four-charged-particle final state, in agreement with the total expected background of about one event. Upper limits of Gamma_gammagamma(eta_b) * BR(eta_b -> 4 charged particles) 6 charged particles) < 132 eV are obtained at 95% confidence level, which correspond to 95% confidence level upper limits of 9.0% and 25% on these branching ratios.

Search for neutral Higgs bosons decaying into four taus at LEP2

A search for the production and non-standard decay of a Higgs boson, h, into four taus through intermediate pseudoscalars, a, is conducted on 683 pb-1 of data collected by the ALEPH experiment at centre-of-mass energies from 183 to 209 GeV. No excess of events above background is observed, and exclusion limits are placed on the combined production cross section times branching ratio, β2 = σ(e+e -→Zh)/σSM(e+e-→Zh) ×B(h→aa)×B(a→τ+τ-) 2. For mh 1 is excluded at the 95% confidence level.

Measurement of Z-pair production in e(+)e(-) collisions and constraints on anomalous neutral gauge couplings

The ZZ production cross section is measured from a data sample corresponding to a total integrated luminosity of 452 pb−1, collected by the ALEPH experiment at LEP at centre-of-mass energies from 192 to 209 GeV. Individual cross sections, extracted at six centre-of-mass energies, are found to be in agreement with Standard Model calculations. The results are used to set limits on anomalous neutral gauge couplings. The ZZ production cross section is measured from a data sample corresponding to a total integrated luminosity of 452 pb−1 , collected by the ALEPH experiment at LEP at centre-of-mass energies from 192 to 209 GeV. Individual cross sections, extracted at six centre-of-mass energies, …

Searches for neutral Higgs bosons in e+e− collisions at centre-of-mass energies from 192 to 202 GeV

Searches for neutral Higgs bosons are performed with the 237 pb-1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of the Standard Model and its minimal supersymmetric extension (MSSM) as well as to invisibly decaying Higgs bosons. No evidence of a signal is seen. A lower limit on the mass of the Standard Model Higgs boson of 107.7 GeV/c2 at 95% confidence level is set. In the MSSM, lower limits of 91.2 and 91.6 GeV/c2 are derived for the masses of the neutral Higgs bosons h and A, respectively. For a Higgs boson decaying invisibly and produced with the Standard Model cros…

Branching Ratios and Spectral Functions of $\tau$ Decays: final ALEPH measurements and physics implications

The full LEP-1 data set collected with the ALEPH detector at the $Z$ pole during 1991-1995 is analysed in order to measure the $\tau$ decay branching fractions. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to over 300 000 measured and identified $\tau$ decays. Branching fractions are obtained for the two leptonic channels and eleven hadronic channels defined by their respective numbers of charged particles and $\pi^0$'s. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied to the hadronic channels to derive branching ratios for exclusive final states without kao…

A flavour-independent Higgs boson search in e+e- collisions at sqrt(s) up to 209GeV

A search for the Higgsstrahlung process e+e- → HZ is carried out, covering decays of the Higgs boson into any quark pair, a gluon pair or a tau pair. The analysis is based on the 630 pb-1 of data collected by the ALEPH detector at LEP at centre-of-mass energies from 189 to 209 GeV. A 95% C.L. lower mass limit of 109.1 GeV/c2 is obtained for a Higgs boson cross section equal to that expected from the Standard Model if the Higgs boson decays exclusively into hadrons and/or taus, irrespective of the relative branching fractions. © 2002 Elsevier Science B.V. All rights reserved.

Supplementary Material for: Barber-Say Syndrome and Ablepharon-Macrostomia Syndrome: A Patient's View

Barber-Say syndrome (BSS) and ablepharon-macrostomia syndrome (AMS) are infrequently reported congenital malformation disorders caused by mutations in the TWIST2 gene. Both are characterized by abnormalities in ectoderm-derived structures and cause a very unusual morphology of mainly the face in individuals with otherwise normal cognition and normal physical functioning. We studied the impact that the presence of BSS and AMS has on psychosocial functioning of affected individuals and their families, using their point of view to start with. We tabulated frequently asked questions from affected individuals and families, and a parent of an affected child and an affected adult woman offered per…

Absolute Lower Limits on the Masses of Selectrons and Sneutrinos in the MSSM

The results of searches for selectrons, charginos and neutralinos performed with the data collected by the ALEPH detector at LEP at centre-of-mass energies up to 209 GeV are interpreted in the framework of the Minimal Supersymmetric extension of the Standard Model with R-parity conservation. Under the assumptions of gaugino and sfermion mass unification and no sfermion mixing, an absolute lower limit of 73 GeV/c2 is set on the mass of the lighter selectron at the 95% confidence level. Similarly, limits on the masses of the heavier selectron and of the sneutrino are set at 107 and 84 GeV/c2, respectively. Additional constraints are derived from the results of the searches for Higgs bosons. T…

Constraints on anomalous QGC's in $e^{+}e^{-}$ interactions from 183 to 209 GeV

The acoplanar photon pairs produced in the reaction e+ e- --> nu nubar gamma gamma are analysed in the 700 inverse nanobarns of data collected by the ALEPH detector at centre-of-mass energies between 183 and 209 GeV. No deviation from the Standard Model predictions is seen in any of the distributions examined. The resulting 95% C.L. limits set on the anomalous QGC's, az_0, az_c, aw_0 and aw_c, are -0.012 GeV**-2 < az_0/Lambda**2 < +0.019 GeV**-2, -0.041 GeV**-2 < az_c/Lambda**2 < +0.044 GeV**-2, -0.060 GeV**-2 < aw_0/Lambda**2 < +0.055 GeV**-2, -0.099 GeV**-2 < aw_c/Lambda**2 < +0.093 GeV**-2, where Lambda is the energy scale of the new Physics responsible for the anomalous couplings.

Inclusive production of the η and ω mesons in Z decays, and the muonic branching ratio of the ω

AbstractThe inclusive production of the η and ω(782) mesons is measured in the π+π−π0 decay mode in hadronic Z decays and compared to model predictions. The analysis is based on 4 million hadronic Z decays recorded by the ALEPH detector between 1991 and 1995. The η production rate for xp=pmeson/pbeam>0.10 is found to be 0.355±0.011stat±0.024sys per event, and the ω production rate for xp>0.05 is measured as 0.585±0.019stat±0.033sys per event. The branching ratio for ω→μ+μ− is investigated. A total of 18.1±5.9 events are observed, from which the muonic branching ratio is measured for the first time to be BR(ω→μ+μ−)=(9.0±2.9stat±1.1sys)×10−5.

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Abstract Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in su…

Fermion pair production in e+e- collisions at 189-209 GeV and constraints on physics beyond the Standard Model

Cross sections, angular distributions and forward-backward asymmetries are presented, of two-fermion events produced in e+e- collisions at centre-of-mass energies from 189 to 209 GeV at LEP, measured with the ALEPH detector. Results for e+e-, mu+mu-, tau+tau-, qq, bb and cc production are in agreement with the Standard Model predictions. Constraints are set on scenarios of new physics such as four-fermion contact interactions, leptoquarks, Z' bosons, TeV-scale quantum gravity and R-parity violating squarks and sneutrinos.

Improved search for $B_{s}^{0} - \overline{B}_{s}^{0}$ oscillations

An improved search for Bs oscillations is performed in the ALEPH data sample collected during the first phase of LEP, and reprocessed in 1998. Three analyses based on complementary event selections are presented. First, decays of Bs mesons into hadronic flavour eigenstates are fully reconstructed. This selection yields a small sample of candidates with excellent decay length and momentum resolution and high average Bs purity. Semileptonic decays with a reconstructed Ds- meson provide a second sample with larger statistics, high average Bs purity, but a poorer momentum and decay length resolution due to the partial decay reconstruction. Finally, semileptonic b-hadron decays are inclusively s…

Haemophagocytic syndrome in rheumatic patients. A systematic review

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH), is a potentially fatal hyperinflammatory syndrome characterized fever, hepatosplenomegaly, and cytopenias. HLH can be either primary, with a genetic aetiology, or secondary, associated with malignancies, autoimmune diseases, or infections. Among rheumatic disorders, HLH occurs most frequently in systemic juvenile idiopathic arthritis. AIM: To draw attention on this severe syndrome that may often go undiagnosed in patient with rheumatic diseases. MATERIALS AND METHODS: PubMed search was performed by combining the terms (haemophagocytic, haemophagocytosis, hemophagocytosis, hemophagocytic, erythrophagocytosis, macrophage activation syndrom…

Anaphylaxis caused by helminths: review of the literature.

BACKGROUND: Anaphylaxis is a severe, life-threatening, generalized or systemic hypersensitivity reaction. In many individuals with anaphylaxis a pivotal role is played by IgE and the high-affinity IgE receptor on mast cells or basophils. Less commonly, it is triggered through other immunologic mechanisms, or through nonimmunologic mechanisms. The human immune response to helminth infections is associated with elevated levels of IgE, tissue eosinophilia and mastocytosis, and the presence of CD4+ T cells that preferentially produce IL-4, IL-5, and IL-13. Individuals exposed to helminth infections may have allergic inflammatory responses to parasites and parasite antigens. AIM: To summarize th…

Search for Supersymmetric Particles in e+e- Collisions at sqrt(s) up to 202GeV and Mass Limit for the Lightest Neutralino

Searches for pair production of squarks, sleptons, charginos, and neutralinos are performed with the data collected by the ALEPH detector at LEP at centre-of-mass energies from 188.6 to 201.6 GeV. No evidence for any such signals is observed in a total integrated luminosity of about 410pb-1. The negative results of the searches are translated into exclusion domains in the space of the relevant MSSM parameters, which improve significantly on the constraints set previously. Under the assumptions of gaugino and sfermion mass unification, these results allow a 95% C.L. lower limit of 37GeV/c2 to be set on the mass of the lightest neutralino for any tan beta and sfermion mass. Additional constra…

Studies of QCD at $e^{+}e^{-}$ centre-of-mass energies between 91 and 209 GeV

The hadronic final states observed with the ALEPH detector at LEP in e(+)e(-) annihilation are analysed using 730 pb(-1) of data collected between 91 and 209 GeV in the framework of QCD. In particular event-shape variables and inclusive charged particle spectra are measured. The energy evolution of quantities derived from these measurements is compared to analytic QCD predictions. The mean charged particle multiplicity, the charged particle momentum spectrum and its peak position are compared to predictions of the modified-leading-logarithmic approximation. The strong coupling constant alpha(s) is determined from a fit of the QCD prediction to distributions of six event-shape variables at e…

Temperature dependence of the static structure factor of ortho-terphenyl in the supercooled liquid regime close to the glass transition

Abstract Studying the temperature dependence of the static structure factor of ortho-terphenyl from the liquid state down to the glass we find that the main peak of S ( Q ) is split into two maxima which behave quite differently. While the maximum at Q =1.4 A −1 is not much affected by the temperature variation the one at 1.9 A −1 is significantly enhanced. This effect is connected with a change of the short range order, i.e. of the intermolecular distances, but evolves continuously. Thus the dynamic anomalies that have been observed in this system around a characteristic temperature T c ≈290 K are not simply due to a discontinuous change in S ( Q ) but can be attributed to the existence of…

Search forBs0→μ+μ−andB0→μ+μ−Decays with CDF II

A search has been performed for B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} and B{sup 0} {yields} {mu}{sup +}{mu}{sup -} decays using 7 fb{sup -1} of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B{sup 0} candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of {Beta}(B{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 6.0 x 10{sup -9} at 95% confidence level. We observe an excess of B{sub s}{sup 0} candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expe…

Measurement of thett¯production cross section inpp¯collisions ats=1.96  TeVusing soft electronb-tagging

The authors present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318 pb{sup -1} of data collected with the CDF II detector, they measure the t{bar t} production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9{sub -1.0}{sup +1.0}(stat.){sub -1.0}{sup +1.1}(syst.) pb. The cross section value assumes a top quark mass of m{sub t} is presented in the paper. This result is cons…

Part of speech tagging with Na&amp;#x00EF;ve Bayes methods

Final results of the searches for neutral Higgs bosons in e+e- collisions at sqrt(s) up to 209GeV

The final results of the ALEPH search for the Standard Model Higgs boson at LEP, with data collected in the year 2000 at centre-of-mass energies up to 209 GeV, are presented. The changes with respect to the preceding publication are described and a complete study of systematic effects is reported. The findings of this final analysis confirm the preliminary results published in November 2000 shortly after the closing down of the LEP collider: a significant excess of events is observed, consistent with the production of a $115 \Gcs$ Standard Model Higgs boson. The final results of the searches for the neutral Higgs bosons of the MSSM are also reported, in terms of limits on $\mh$, $\mA$ and $…

Search for pentaquarks states in Z decays

Exotic hadrons made of five quarks (pentaquarks) are searched for in hadronic Z decays collected by the ALEPH detector at LEP. No significant signal is observed. At 95% C.L. upper limits are set on the production rates N of such particles and their charge-conjugate state per Z decay: N Θ(1535)+·BR(Θ(1535)+→pK S0)<6.2×10-4, N Ε(1862)-·BR(Ε(1862)-→Ε -π-)<4.5×10-4, N Ε(1862)0·BR(Ε(1862)0→Ε -π+)<8.9×10-4, N Θc(3100)0·BR(Θc(3100) 0→D*-p)<6.3×10-4, N Θc(3100)0·BR(Θc(3100) 0→D-p)<31×10-4. © 2004 Elsevier B.V. All rights reserved.

Deuteron and anti-deuteron production in e+e− collisions at the Z resonance

Deuteron and anti-deuteron production in Z decays has been observed in the ALEPH experiment at LEP. The production rate of anti-deuterons is measured to be 5.9+-1.8+-0.5 10^-6 per hadronic Z decay in the anti-deuteron momentum range 0.62 to 1.03 GeV/c. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033+-0.0013 GeV^2 in Z dedays. These measurements indicate that the production of anti-deuterons is suppressed in e+e- collisions compared to pp and photoproduction collisions.

Search for γγ decays of a Higgs boson in e+e- collisions at √s up to 209 GeV

A search for events with a photon pair arising from the decay of a Higgs boson produced in association with a fermion pair, is performed in 893 pb-1 of data recorded by the ALEPH detector at LEP at centre-of-mass energies up to 209 GeV. No excess of such events is found over the expected background, An upper limit is derived on the product of the e+e- → HZ cross section and the H → γγ branching fraction as a function of the Higgs boson mass. A fermiophobic Higgs boson produced with the Standard Model cross section is excluded at 95% confidence level for all masses below 105.4 GeV/c2. © 2002 Elsevier Science B.V. All rights reserved.

Bose-Einstein correlations in W-pair decays with an event-mixing technique

Bose-Einstein correlations in W-pair decays are studied using data collected by the ALEPH detector at LEP at e(+)e(-) centre-of-mass energies from 183 to 209 GeV. The analysis is based on the comparison of WW --> q (q) over barq (q) over bar events to "mixed" events constructed with the hadronic part of WW --> q (q) over bar lv events. The data are in agreement with the hypothesis that Bose-Einstein correlations are present only for pions from the same W decay. The JETSET model with Bose-Einstein correlations between pions from different W bosons is disfavoured. (C) 2004 Elsevier B.V. All rights reserved.

Search for Higgs bosons decaying to WW in e(+)e(-) stope collisions at LEP

A search for Higgs bosons produced in association with a fermion pair, and decaying to WW, is performed with the data collected by the ALEPH detector at centre-of-mass energies ranging from 191 to 209 GeV. The data correspond to an integrated luminosity of 453.2 pb^-1. Thirteen exclusive selections are developed according to the different final state topologies. No statistically significant evidence for a Higgs boson decaying into a WW pair has been found. An upper limit is derived, as a function of the Higgs boson mass, on the product of the e+e- -&gt; Hff cross section and the H -&gt; WW branching ratio. The data on the search for H -&gt; WW are combined with previously published ALEPH re…

Part-of-speech labeling for Reuters database

Even if the Vector Space Model used for document representation in information retrieval systems integrates a small quantity of knowledge it continues to be used due to its computational cost, speed execution and simplicity. We try to improve this document representation by adding some syntactic information such as the parts of speech. In this paper, we have evaluated three different tagging algorithms in order to select the most suitable tagger for using it to tag the Reuters dataset. In this work, we have evaluated the taggers using only five different parts of speech: noun, verb, adverb, adjective and others. We considered these particular tags being the most representative for describin…

Production of Ds** mesons in hadronic Z decays

The production rates of the orbitally excited Ds** mesons, Ds1 and Ds2*, are measured with the 4.1 million hadronic Z decays recorded by the ALEPH detector during 1991--1995. The Ds** mesons are reconstructed in the decay modes Ds1+ -&gt; D*+ K0, Ds1+ -&gt; D*0 K+ and Ds2*+ -&gt; D0 K+. The production rate of the Ds1 is measured to be n(Z-&gt;Ds1+-)=(0.52+-0.09+-0.06)%, under the assumption that the two considered decay modes of the Ds1 saturate the branching ratio. The production rate of the Ds2* is determined to be n(Z-&gt;Ds2*+-)=(0.83+-0.29+0.07-0.13)%, assuming that the branching fraction of the decay Ds2*+ -&gt; D0 K+ is 45%. The production rates in Z-&gt;cc and Z-&gt;bbar decays are …

Search for charginos nearly mass degenerate with the lightest neutralino in e+e− collisions at centre-of-mass energies up to 209 GeV

A search for charginos nearly mass degenerate with the lightest neutralino is performed with the data collected by the ALEPH detector at LEP, at centre-of-mass energies between 189 and 209 GeV, corresponding to an integrated luminosity of 628 pb-1. The analysis is based on the detection of isolated and energetic initial state radiation photons, produced in association with chargino pairs whose decay products have little visible energy. The number of candidate events observed is in agreement with that expected from Standard Model background sources. These results are combined with those of other direct searches for charginos, and a lower limit of 88 GeV/c2 at 95 % confidence level is derived…

Exclusive production of pion and kaon meson pairs in two photon collisions at LEP

Exclusive production of pi and K meson pairs in two photon collisions is measured with ALEPH data collected between 1992 and 2000. Cross-sections are presented as a function of cos theta* and invariant mass, for \ cos theta* \ < 0.6 and invariant masses between 2.0 and 6.0 GeV/c(2) (2.25 and 4.0 GeV/c(2)) for pions (kaons). The shape of the distributions are found to be well described by QCD predictions but the data have a significantly higher normalization. (C) 2003 Published by Elsevier B.V.

Search for neutral MSSM Higgs bosons at LEP

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of "benchmark" models, including CP-conserving and CP-violating scenarios. Thes…

Leptonic decays of the D-s meson

The purely leptonic decays Ds -&gt; tau nu and Ds -&gt; mu nu are studied in a sample of four million hadronic Z decays collected with the ALEPH detector at the LEP e+e- collider from 1991 to 1995. The branching fractions are extracted from a combination of two analyses, one optimized to select Ds -&gt; tau nu decays with tau -&gt; e nu nubar or mu nu nubar, and the other optimized for Ds-&gt; mu nu decays. The results are used to evaluate the Ds decay constant, within the Standard Model: fDs = [285 +- 19(stat) +- 40 (syst)] MeV

Inclusive semileptonic branching ratios of b hadrons produced in Z decays

A measurement of the inclusive semileptonic branching ratios of b hadrons produced in Z decay is presented, using four million hadronic events collected by the ALEPH detector from 1991 to 1995. Electrons and muons are selected opposite to b-tagged hemispheres. Two different methods are explored to distinguish the contributions from direct $\bl$ and cascade $\bcl$ decays to the total lepton yield. One is based on the lepton transverse momentum spectrum, the other makes use of the correlation between the charge of the lepton and charge estimators built from tracks in the opposite hemisphere of the event. The latter method reduces the dependence on the modelling of semileptonic b decays. The r…

Observation of an excess in the search for the Standard Model Higgs boson at ALEPH

A search has been performed for the Standard Model Higgs boson in the data sample collected with the ALEPH detector at LEP, at centre-of-mass energies up to 209GeV. An excess of 3sigma beyond the background expectation is found, consistent with the production of the Higgs boson with a mass near 114GeV/c2. Much of this excess is seen in the four-jet analyses, where three high purity events are selected.