Search

Measuring the shape of the Higgs boson potential is of paramount importance, and will be a challenging task at current as well as future colliders. While the expectations for the measurement of the trilinear Higgs self-coupling are rather promising, an accurate measurement of the quartic self-coupling interaction is presently considered extremely challenging even at a future 100 TeV proton-proton collider. In this work we explore the sensitivity that a muon collider with a center of mass energy in the multi-TeV range and luminosities of the order of 1035cm−2s−1, as presently under discussion, might provide, thanks to a rather large three Higgs-boson production and to a limited background. By performing a first and simple analysis, we find a clear indication that a muon collider could provide a determination of the quartic Higgs self-coupling that is significantly better than what is currently considered attainable at other future colliders. [ABSTRACT FROM AUTHOR]

We review the current status of the theory predictions for elastic μ -e scattering, describing the recent activities and future plans of the theory initiative related to the proposed MUonE experiment. [ABSTRACT FROM AUTHOR]

We present a Monte-Carlo implementation of the Statistical Hadronization Model in ee collisions. The physical scheme is based on the statistical hadronization of massive clusters produced by the event generator Herwig within the microcanonical ensemble. We present a preliminary comparison of several observables with measurements in ee collisions at the Z peak. Although a fine tuning of the model parameters is not carried out, a general good agreement between its predictions and data is found. [ABSTRACT FROM AUTHOR]

Summary: In the past few years the field of hadron spectroscopy has seen renewed interest due to the publication, initially mostly from B-Factories, of evidences of states that do not match regular spectroscopy, but are rather candidates for bound states with additional quarks or gluons. A huge effort in understanding the nature of these new states and in building a new spectroscopy is ongoing. This report reviews the experimental and theoretical state of the art on heavy quarkonium exotic spectroscopy, with particular attention on the steps towards a global picture. [ABSTRACT FROM AUTHOR]

We compute the full one-loop EW contributions of ${\mathcal{O}}(\alpha_{\mathrm{S}}\alpha_{\mathrm{EM}}^{3})$ entering the electron–positron into two b-quarks and one gluon cross section at the Z peak and LC energies. We include both factorisable and non-factorisable virtual corrections, photon bremsstrahlung but not the real emission of W± and Z bosons. Their importance for the measurement of αS from jet rates and shape variables is explained qualitatively and illustrated quantitatively. Their impact on the forward–backward asymmetry is also analysed. [ABSTRACT FROM AUTHOR]

We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences. [ABSTRACT FROM AUTHOR]

We compute, in the MSSM framework, the sum of the one-loop electroweak and of the total QED radiation effects for the process $pp \to t W+X$ , initiated by the parton process $bg\to tW$ . Combining these terms with the existing NLO calculations of SM and SUSY QCD corrections, we analyze the overall one-loop supersymmetric effects on the partial rates of the process, obtained by integrating the differential cross section up to a final variable invariant mass. We conclude that, for some choices of the SUSY parameters and for relatively small final invariant masses, they could reach the relative ten percent level, possibly relevant for a dedicated experimental effort at LHC. [ABSTRACT FROM AUTHOR]

Based on the observation that K0 *(1430) is lighter than its SU3 counterpart, a0(1450), we examine the possibility that these particles, together with f0(1370), f0(1500) and f0(1710), fill a tetraquark recurrence of the sub-GeV 0++ nonet mixed with a glueball state. We find the picture to be consistent with the known data about the three f0 resonances, more than the qq̄ hypothesis. Conventional spin–orbit coupling suggests the qq̄, P-wave, nonet to lie around 1200 MeV. We review possible experimental indications of a scalar isovector resonance at 1.29 GeV, first observed by OBELIX in pp̄ annihilation. [ABSTRACT FROM AUTHOR]

We present a study of the cross sections J/ψX→D(*)D̄(*) (X=ρ, Φ) based on the calculation of the effective tri- and four-linear couplings J/ψ X D(*) D̄(*) within a constituent quark model. In particular, the method for the calculation of the four-linear couplings is illustrated. The results obtained have been used in a recent analysis of J/ψ absorption by the hot hadron gas formed heavy-ion collisions at SPS energies. [ABSTRACT FROM AUTHOR]

The production of the σ(500) meson in γγ→π0π0 is studied. In particular, the KLOE data collected during the DAΦNE run at $\sqrt{s}=1 \mathrm{GeV}$ are appropriate to this purpose because of the strong reduction of kaon backgrounds. [ABSTRACT FROM AUTHOR]

Objective: Few dinical trials have examined the effects of nitric oxide donors on the human cervix. We address the question of the ultrastructural and clinical effects of topical NO donor on the nonpregnant human cervix. Methods: Twenty patients admitted to the hospital for hysterectomy were randomly assigned to receive either placebo gel or 1% nitroprusside-based gel into the cervical canal. After surgery, a small biopsy of the cervical canal was taken and analyzed by electron microscopy. Vital parameters were monitored after application. Results: In the placebo group, the connective tissue was normal. The collagen fibers wre widely spaced, and no longitudinal collagen bundles were visible. Macrophages, leukocytes, and activated fibroblasts in treated tissues demonstrated a proinflammatory reaction. Adverse effect were reported in a minority of subjects. No significant changes in blood pressure or in nitrite and nitrate levels were reported. Conclusion: In both fertile and postmenopausal women, cervical sodium nitroprusside induced morphologic changes similar to those reported for the ripening process. [ABSTRACT FROM AUTHOR]

The production of four fermions plus a visible photon in electron–positron collisions is analyzed, with particular emphasis on the LEP2 energy range. The study is based on the calculation of exact matrix elements, including the effect of fermion masses. In the light of the present measurements performed at LEP, triple and quartic anomalous gauge couplings are taken into account. Due to the presence of a visible photon in the final state, particular attention is paid to the treatment of higher-order QED corrections. Explicit results for integrated cross sections and differential distributions are shown and commented on. The features of the Monte Carlo program WRAP, used to perform the calculation and available for experimental analysis, are described. [ABSTRACT FROM AUTHOR]

Four-fermion processes with a particle lost in the beam pipe are studied at LEP to perform precision tests of the electroweak theory. Leading higher-order QED corrections to such processes are analyzed within the framework of the structure function (SF) approach. The energy scale entering the QED SF is determined by inspection of the soft and collinear limit of the $O(\alpha)$ radiative corrections to the four-fermion final states, paying particular attention to the process of single- W production. Numerical predictions are shown in realistic situations for LEP experiments and compared with existing results. A Monte Carlo event generator, including exact tree-level matrix elements, vacuum polarization, higher-order leading QED corrections and anomalous trilinear gauge couplings, is presented. [ABSTRACT FROM AUTHOR]

Objective:This study investigates the biochemical and cardiovascular effects of L-arginine administration in normotensive pregnant women and women with preeclampsia.Methods:The study groups consisted of 12 women with uncomplicated pregnancies and 17 preeclamptic patients, four of whom were on antihypertensive treatment. In both groups, saline infusion was started, followed by 30 g L-arginine administration, and finally more saline. Blood pressure was recorded every 5 minutes and blood samples were collected for measurement of serum citrulline, arginine, and nitrite levels. Amino acid assays were done by using high-performance liquid chromatography with fluorometric detection.Results:L-Arginine infusion was associated with a significant reduction of blood pressure in both groups, the decrease being greater in the women with preeclampsia. Baseline serum citrulline and arginine levels were not significantly different between the two groups. L-Citrulline levels were significantly increased during infusion of L-arginine, and the increase was significantly lower in the women with preeclampsia. Serum nitrite levels were increased only in controls and not in preeclampsia patients. The total citrulline production stimulated by L-arginine was related inversely to baseline blood pressure values and was unrelated to clinical parameters such as gestational age at delivery, birth weight, and Apgar score.Conclusions:L-arginine load in pregnant women is associated with increased nitric oxide (NO) production and hypotension. Despite a reduced ability to produce NO, patients with preeclampsia may benefit from L-arginine supplementation. Overall, these findings partially support the hypothesis that preeclampsia is characterized by a dysfunction of the L-arginine-NO pathway. [ABSTRACT FROM PUBLISHER]

The six-fermion production processes $e^+e^-\rightarrow q\bar q l^+ l^-\nu\bar\nu$, with all the lepton flavours and $q=u,d,c,s$, relevant to the study of the intermediate-mass Higgs boson at future $e^+e^-$ linear colliders are analysed. A Monte Carlo program, taking into account the whole set of tree-level scattering amplitudes and the relevant radiative effects, is developed to provide integrated cross-sections and generation of unweighted events. The complete calculation is compared with the available results of real Higgs production, and the opportunities of precision studies with event generation are discussed, demonstrating the relevance of a full six-fermion calculation. Numerical results for integrated cross-sections with various kinematical cuts and including radiative effects are given and commented. In the analysis of event samples, several distributions are studied and found to be sensitive to the presence and to the properties of the Higgs boson. [ABSTRACT FROM AUTHOR]

It is shown that a Rarita-Schwinger (spin 3/2) particle in an external electromagnetic field besides exhibiting acausal propagation also violates tree unitarity for semi-classical scattering. This suggests a general connection between acausal propagation and the violation of tree unitarity for high-spin (≥1) fields. [ABSTRACT FROM AUTHOR]

The cardiotoxic and cytotoxic effects of the Cu(II)-doxorubicin (DXR) complex [Cu(DXR)]n are compared with those of the parent drug. It is shown that 10(-4) M [Cu(DXR)]n has no depressant effects on isolated rat atria, in contrast with an equimolar concentration of the parent drug. No differences were found between the cytotoxic activities of the Cu(II) complex and free DXR on B16 melanoma and HeLa cells. A reduced penetration of the polymeric [Cu(DXR)]n into the myocardial cells as compared with the free drug was invoked to account for the absence of cardiotoxicity of the DXR complex. On the other hand, the observation that copper-complexation does not affect the cytotoxicity of the drug suggests that extracellular as well as intracellular mechanisms may be involved in the development of its antitumor activity. [ABSTRACT FROM AUTHOR]

We consider the effects of a number of models with one extra Z, with enhanced couplings to quarks, in the final hadronic channels at LEP2. We show that, for a number of representative cases, visible effects could be produced even for very low values of the lepton couplings, much smaller than the existing LEP1/SLC and the future LEP2 (lepton channel) bounds. [ABSTRACT FROM AUTHOR]

Copyright of Experientia is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A single administration of adriamycin (DXR) 6.0 mg/kg i.v. to rats brings about a biphasic impairment of the maximal myocardial contractile performance, measured as dF/dt of ex vivo isolated atria incubated in the presence of calcium concentrations varying up to 12 mM. The initial impairment of the contractile performance peaks 1 week after DXR administration and recovers within 3 weeks (acute phase of cardiotoxicity). After this time and up to the end of the observation period (8 weeks after treatment), delayed cardiotoxicity occurs, showing a progressive and irreversible impairment of the contractile performance of the atria. This behaviour parallels the previously shown ECG and morphological abnormalities. Tissue determinations of DXR showed that the drug is present in myocardium during the acute phase of cardiotoxicity, while the metabolite adriamycinol is not detectable 1 week after DXR administration. These data show that the presence of DXR and/or metabolites in heart muscle is not necessary for the delayed form of cardiotoxicity to become apparent and suggest that this form of cardiotoxicity is related to a mechanism different from that involved in acute cardiotoxicity. [ABSTRACT FROM AUTHOR]

Lanthanum reduces the rate of calcium fast exchanging processes, whereas the slowly exchanging phase is not modified. Experimental data also confirm the importance of calcium fast exchanging fraction in regulating contractile force of cardiac muscle. [ABSTRACT FROM AUTHOR]

The stimulatory effect of PGE on different functions of isolated guinea-pig hearts (Langendorff method, Tyrode solution) was coupled with an increase in the rate ofCa uptake from the perfusion medium. The total myocardial Ca content and the amount of exchangeable cellular Ca were not affected. This action of PGE on the myocardial Ca metabolism seems to be related to the positive inotropic action of PGE and can most probably be explained by an increase in the membrane permeability to Ca ions (similar to the action of epinephrine). [ABSTRACT FROM AUTHOR]

Copyright of Experientia is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We describe the impact of the full one-loop EW terms of 풪(αSαEM3) entering the electron-positron into three-jet cross-section from = MZ to TeV scale energies. We include both factorisable and non-factorisable virtual corrections, photon bremsstrahlung but not the real emission of W± and Z bosons. Their importance for the measurement of αS from jet rates and shape variables is explained. [ABSTRACT FROM AUTHOR]