Genuine Correlations of Like-Sign Particles in Hadronic Z0 Decays

Correlations among hadrons with the same electric charge produced in Z0 decays are studied using the high statistics data collected from 1991 through 1995 with the OPAL detector at LEP. Normalized factorial cumulants up to fourth order are used to measure genuine particle correlations as a function of the size of phase space domains in rapidity, azimuthal angle and transverse momentum. Both all-charge and like-sign particle combinations show strong positive genuine correlations. One-dimensional cumulants initially increase rapidly with decreasing size of the phase space cells but saturate quickly. In contrast, cumulants in two- and three-dimensional domains continue to increase. The strong rise of the cumulants for all-charge multiplets is increasingly driven by that of like-sign multiplets. This points to the likely influence of Bose-Einstein correlations. Some of the recently proposed algorithms to simulate Bose-Einstein effects, implemented in the Monte Carlo model PYTHIA, are found to reproduce reasonably well the measured second- and higher-order correlations between particles with the same charge as well as those in all-charge particle multiplets.Comment: 26 pages, 6 figures, Submitted to Phys. Lett.

The Mexican consensus on non-cardiac chest pain

Introduction: Non-cardiac chest pain is defined as a clinical syndrome characterized by ret-rosternal pain similar to that of angina pectoris, but of non-cardiac origin and produced byesophageal, musculoskeletal, pulmonary, or psychiatric diseases. Aim: To present a consensus review based on evidence regarding the definition, epidemiology,pathophysiology, and diagnosis of non-cardiac chest pain, as well as the therapeutic options forthose patients. Methods Three general coordinators carried out a literature review of all articles published inEnglish and Spanish on the theme and formulated 38 initial statements, dividing them into 3 maincategories: 1) definitions, epidemiology, and pathophysiology, 2) diagnosis, and 3) treatment.The statements underwent 3 rounds of voting, utilizing the Delphi system. The final statementswere those that reached > 75% agreement, and they were rated utilizing the GRADE system. Results and conclusions The final consensus included 29 statements. All patients presentingwith chest pain should initially be evaluated by a cardiologist. The most common cause of non-cardiac chest pain is gastroesophageal reflux disease. If there are no alarm symptoms, the initialapproach should be a therapeutic trial with a proton pump inhibitor for 2-4 weeks. If dysphagiaor alarm symptoms are present, endoscopy is recommended. High-resolution manometry isthe best method for ruling out spastic motor disorders and achalasia and pH monitoring aidsin demonstrating abnormal esophageal acid exposure. Treatment should be directed at thepathophysiologic mechanism. It can include proton pump inhibitors, neuromodulators and/orsmooth muscle relaxants, psychologic intervention and/or cognitive therapy, and occasionallysurgery or endoscopic therapy

Consenso mexicano sobre dolor torácico no cardiaco

Introducción: Dolor torácico no cardíaco (DTNC) se define como un síndrome clínico caracte-rizado por dolor retroesternal semejante a la angina de pecho, pero de origen no cardiaco ygenerado por enfermedades esofágicas, osteomusculares, pulmonares o psiquiátricas.Objetivo: Presentar una revisión consensuada basada en evidencias sobre definición, epidemio-logía, fisiopatología, diagnóstico y opciones terapéuticas para pacientes con DTNC.Métodos: Tres coordinadores generales realizaron una revisión bibliográfica de todas las publi-caciones en inglés y espa˜nol sobre el tema y elaboraron 38 enunciados iniciales divididosen tres categorías principales: 1) definiciones, epidemiología y fisiopatología; 2) diagnóstico,y 3) tratamiento. Los enunciados fueron votados (3 rondas) utilizando el sistema Delphi, y losque alcanzaron un acuerdo > 75% fueron considerados y calificados de acuerdo con el sistemaGRADE. Resultados y conclusiones: El consenso final incluyó 29 enunciados Todo paciente que debutacon dolor torácico debe ser inicialmente evaluado por un cardiólogo. La causa más común deDTNC es la enfermedad por reflujo gastroesofágico (ERGE). Como abordaje inicial, si no existensíntomas de alarma, se puede dar una prueba terapéutica con inhibidor de bomba de pro-tones (IBP) por 2-4 semanas. Si hay disfagia o síntomas de alarma, se recomienda hacer unaendoscopia. La manometría de alta resolución es el mejor método para descartar trastornosmotores espásticos y acalasia. La pHmetría ayuda a demostrar exposición esofágica anormal alácido. El tratamiento debe ser dirigido al mecanismo fisiopatológico, y puede incluir IBP, neu-romoduladores y/o relajantes de músculo liso, intervención psicológica y/o terapia cognitiva,y ocasionalmente cirugía o terapia endoscópica. ABSTRACT Introduction: Non-cardiac chest pain is defined as a clinical syndrome characterized by retros-ternal pain similar to that of angina pectoris, but of non-cardiac origin and produced byesophageal, musculoskeletal, pulmonary, or psychiatric diseases.Aim: To present a consensus review based on evidence regarding the definition, epidemiology,pathophysiology, and diagnosis of non-cardiac chest pain, as well as the therapeutic options forthose patients. Methods: Three general coordinators carried out a literature review of all articles published inEnglish and Spanish on the theme and formulated 38 initial statements, dividing them into 3 maincategories: (i) definitions, epidemiology, and pathophysiology; (ii) diagnosis, and (iii) treatment.The statements underwent 3 rounds of voting, utilizing the Delphi system. The final statementswere those that reached > 75% agreement, and they were rated utilizing the GRADE system.Results and conclusions: The final consensus included 29 statements. All patients presentingwith chest pain should initially be evaluated by a cardiologist. The most common cause ofnon-cardiac chest pain is gastroesophageal reflux disease. If there are no alarm symptoms, the initial approach should be a therapeutic trial with a proton pump inhibitor for 2-4 weeks. Ifdysphagia or alarm symptoms are present, endoscopy is recommended. High-resolution mano-metry is the best method for ruling out spastic motor disorders and achalasia and pH monitoringaids in demonstrating abnormal esophageal acid exposure. Treatment should be directed at thepathophysiologic mechanism. It can include proton pump inhibitors, neuromodulators and/orsmooth muscle relaxants, psychologic intervention and/or cognitive therapy, and occasionallysurgery or endoscopic therapy

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

Measurement of the partial widths of the Z into up- and down-type quarks

Using the entire OPAL LEP1 on-peak Z hadronic decay sample, Z -> qbarq gamma decays were selected by tagging hadronic final states with isolated photon candidates in the electromagnetic calorimeter. Combining the measured rates of Z -> qbarq gamma decays with the total rate of hadronic Z decays permits the simultaneous determination of the widths of the Z into up- and down-type quarks. The values obtained, with total errors, were Gamma u = 300 ^{+19}_{-18} MeV and Gamma d = 381 ^{+12}_{-12} MeV. The results are in good agreement with the Standard Model expectation.Comment: 22 pages, 5 figures, Submitted to Phys. Letts.

Measurement of Rb in e+e- Collisions at 182 - 209 GeV

Measurements of Rb, the ratio of the bbbar cross-section to the qqbar cross- section in e+e- collisions, are presented. The data were collected by the OPAL experiment at LEP at centre-of-mass energies between 182 GeV and 209 GeV. Lepton, lifetime and event shape information is used to tag events containing b quarks with high efficiency. The data are compatible with the Standard Model expectation. The mean ratio of the eight measurements reported here to the Standard Model prediction is 1.055+-0.031+-0.037, where the first error is statistical and the second systematic.Comment: 21 pages, 5 figures, Submitted to Phys. Letts

Search for contact interactions, large extra dimensions and finite quark radius in ep collisions at HERA

A search for physics beyond the Standard Model has been performed with high-Q^2 neutral current deep inelastic scattering events recorded with the ZEUS detector at HERA. Two data sets, e^+ p \to e^+ X and e^- p \to e^- X, with respective integrated luminosities of 112 pb^-1 and 16 pb^-1, were analyzed. The data reach Q^2 values as high as 40000 GeV^2. No significant deviations from Standard Model predictions were observed. Limits were derived on the effective mass scale in eeqq contact interactions, the ratio of leptoquark mass to the Yukawa coupling for heavy leptoquark models and the mass scale parameter in models with large extra dimensions. The limit on the quark charge radius, in the classical form factor approximation, is 0.85 10^-16 cm.Comment: 28 pages, 4 figures, accepted for publication in Physics Letters

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

WW Production Cross Section and W Branching Fractions in e+e- Collisions at 189 GeV

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.Comment: 22 pages, 5 figures, submitted to Phys. Lett.

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results