The experimental determination of the properties of the newly discovered boson at the Large Hadron Collider is currently the most crucial task in high-energy physics. We show how information about ...the spin, parity, and, more generally, the tensor structure of the boson couplings can be obtained by studying angular and mass distributions of events in which the resonance decays to pairs of gauge bosons, ZZ, WW, and gamma gamma . A complete Monte Carlo simulation of the process pp arrow right X arrow right VV arrow right 4functionof is performed and verified by comparing it to an analytic calculation of the decay amplitudes X arrow right VV arrow right 4functionof. Our studies account for all spin correlations and include general couplings of a spin J = 0, 1, 2 resonance to Standard Model particles. We also discuss how to use angular and mass distributions of the resonance decay products for optimal background rejection. It is shown that by the end of the 8 TeV run of the LHC, it might be possible to separate extreme hypotheses of the spin and parity of the new boson with a confidence level of 99% or better for a wide range of models. We briefly discuss the feasibility of testing scenarios where the resonance is not a parity eigenstate.
Review of Particle Physics Tanabashi, M.; Nakamura, K.; Tanaka, J. ...
Physical review. D,
08/2018, Letnik:
98, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements from 758 papers, we list, evaluate, and average measured properties of ...gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 118 reviews are many that are new or heavily revised, including a new review on Neutrinos in Cosmology.
The indications for intracranial pressure (ICP) monitoring in patients with acute brain injury and the effects of ICP on patients’ outcomes are uncertain. The aims of this study were to describe ...current ICP monitoring practises for patients with acute brain injury at centres around the world and to assess variations in indications for ICP monitoring and interventions, and their association with long-term patient outcomes.
We did a prospective, observational cohort study at 146 intensive care units (ICUs) in 42 countries. We assessed for eligibility all patients aged 18 years or older who were admitted to the ICU with either acute brain injury due to primary haemorrhagic stroke (including intracranial haemorrhage or subarachnoid haemorrhage) or traumatic brain injury. We included patients with altered levels of consciousness at ICU admission or within the first 48 h after the brain injury, as defined by the Glasgow Coma Scale (GCS) eye response score of 1 (no eye opening) and a GCS motor response score of at least 5 (not obeying commands). Patients not admitted to the ICU or with other forms of acute brain injury were excluded from the study. Between-centre differences in use of ICP monitoring were quantified by using the median odds ratio (MOR). We used the therapy intensity level (TIL) to quantify practice variations in ICP interventions. Primary endpoints were 6 month mortality and 6 month Glasgow Outcome Scale Extended (GOSE) score. A propensity score method with inverse probability of treatment weighting was used to estimate the association between use of ICP monitoring and these 6 month outcomes, independently of measured baseline covariates. This study is registered with ClinicalTrial.gov, NCT03257904.
Between March 15, 2018, and April 30, 2019, 4776 patients were assessed for eligibility and 2395 patients were included in the study, including 1287 (54%) with traumatic brain injury, 587 (25%) with intracranial haemorrhage, and 521 (22%) with subarachnoid haemorrhage. The median age of patients was 55 years (IQR 39–69) and 1567 (65%) patients were male. Considerable variability was recorded in the use of ICP monitoring across centres (MOR 4·5, 95% CI 3·8–4·9 between two randomly selected centres for patients with similar covariates). 6 month mortality was lower in patients who had ICP monitoring (441/1318 34%) than in those who were not monitored (517/1049 49%; p<0·0001). ICP monitoring was associated with significantly lower 6 month mortality in patients with at least one unreactive pupil (hazard ratio HR 0·35, 95% CI 0·26–0·47; p<0·0001), and better neurological outcome at 6 months (odds ratio 0·38, 95% CI 0·26–0·56; p=0·0025). Median TIL was higher in patients with ICP monitoring (9 IQR 7–12) than in those who were not monitored (5 3–8; p<0·0001) and an increment of one point in TIL was associated with a reduction in mortality (HR 0·94, 95% CI 0·91–0·98; p=0·0011).
The use of ICP monitoring and ICP management varies greatly across centres and countries. The use of ICP monitoring might be associated with a more intensive therapeutic approach and with lower 6-month mortality in more severe cases. Intracranial hypertension treatment guided by monitoring might be considered in severe cases due to the potential associated improvement in long-term clinical results.
University of Milano-Bicocca and the European Society of Intensive Care Medicine.
Objective: identify the most acceptable options of anesthesia at urgent operative interventions concerning thoracoabdominal injuries depending on hemodynamic variables. Materials and methods: a ...retrospective analysis of medical cards of 203 patients treated in a specialized departament about thoracoabdominal injuries. The severity of injuries according to ISS was 21.2±7.0 points. We estimated the impact of different anesthesia methods on such hemodynamic parameters as mean arterial pressure, heart rate, Кerdo index, Allgower index. For statistical data processing we used the program Microsoft Office Excel 2007, as well as automatic calculators site www.medcalc.org. Results: in patients with thoracoabdominal injuries commonly used inhalation anesthesia. The choice of method of anesthesia is based on anesthesiology-operation risk and indicators of hemodynamics in the preoperative period. The most commonly observed unstable hemodynamics during anesthesia with ketamine and nitrous oxide, the least – during anesthesia with propofol and sevoflurane. At high values of Kerdo index is more likely to occur when stable hemodynamics using propofol and sevoflurane, at low values – when using nitrous oxide and ketamine. In terms of total intravenous anesthesia ketamine patients often required the use of drugs with inotropic effects. Conclusions: If thoracoabdominal trauma patients with a predominance of the sympathetic tone of the nervous system, treatment of choice is anesthetic management total intravenous anesthesia using ketamine. In patients with a predominance of activity of the parasympathetic nervous system is possible to use inhalation anaesthesia.
Many models of physics beyond the standard model predict the existence of new Abelian forces with new gauge bosons mediating interactions between "dark sectors" and the standard model. We report a ...search for a dark boson Z' coupling only to the second and third generations of leptons in the reaction e super(+) e super(?)arrowrightmu super(+)mu super(?)Z',Z'arrowrightmu super(+) mu? using 514fb super(?1) of data collected by the BABAR experiment. No significant signal is observed for Z' masses in the range 0.212-10 GeV. Limits on the coupling parameter g' as low as 7x10 super(?4) are derived, leading to improvements in the bounds compared to those previously derived from neutrino experiments.
The LHC effective field theory working group gathers members of the LHC experiments and the theory community to provide a framework for the interpretation of LHC data in the context of EFT. In this ...note we discuss experimental observables and corresponding measurements in analysis of the Higgs, top, and electroweak data at the LHC. We review the relationship between operators and measurements relevant for the interpretation of experimental data in the context of a global SMEFT analysis. One of the goals of ongoing effort is bridging the gap between theory and experimental communities working on EFT, and in particular concerning optimised analyses. This note serves as a guide to experimental measurements and observables leading to EFT fits and establishes good practice, but does not present authoritative guidelines how those measurements should be performed.
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