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.
Synthetic, structural, and thermodynamic aspects of the recently discovered new reaction, donor-acceptor coordination of anions (A
–
) by chalcogen atoms (E) of 1,2,5-chalcogenadiazoles, are ...considered. According to the quantum chemical calculations, the charge transfer from A
–
to the heterocycle
via
the mechanism of negative hyperconjugation (
i.e
., from the MO of the lone pair of A
–
to the virtual σ* orbital of the E—N bond of chalcogenadiazole) depends on the nature of E and A
–
, being 0.42—0.52 and 0.30—0.44 e in terms of the Mulliken and NBO methods, respectively. According to the X-ray diffraction data, the E—A
–
coordinate bond is always longer than the sum of the covalent radii but shorter than the sum of the van der Waals radii of the atoms forming the bond. The E—A
–
bond energy varies in a wide range, from ~25 kcal mol
–1
comparable to the energy of weak covalent bonds (
e.g
., internal N—N bond in organic azides) to ~86 kcal mol
–1
comparable to the C—C bond energy in organic compounds. The quantum chemical estimations of the thermodynamics of the donor-acceptor coordination of the anions by the chalcogen atoms of 1,2,5-chalcogenadiazoles indicate that for E = Te and Se this reaction may be of general character also covering E = S in some cases.
A novel β-ketoimine-functionalized 2,1,3-benzothiadiazole (4-(2,1,3-benzothiadiazole-4-ylamino)pent-3-en-2-one, L2H ) was synthesized and used as chelating ligand for the complexation with Zn( ii ) ...(complex ZnL2 ). The spectroscopic and photophysical properties of L2H and ZnL2 as well as those of previously described 4-amino-2,1,3-benzothiadiazole ( L1 ) and its complex ZnL1 have been thoroughly studied in the crystalline state and solution. The UV-Vis absorption spectra of free ligands L1 , L2H and its deprotonated form L2 − , and complexes ZnL1 and ZnL2 were assigned on the basis of TD-DFT calculations. In contrast to ZnL2 having conventional single-band fluorescence, ZnL1 demonstrates a broad double-band purple-white fluorescence spanning the entire visible region. On the basis of careful spectroscopic studies the second band of this unusual fluorescence spectrum was attributed to the presence of traces of free ligand L1 in the crystals of complex ZnL1 . The energy transfer from the excited state of ZnL1 to a free ligand L1 was revealed.
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.
We present an extension of the JHUGen and MELA framework, which includes an event generator and library for the matrix element analysis. It enables simulation, optimal discrimination, reweighting ...techniques, and analysis of a bosonic resonance and the triple and quartic gauge boson interactions with the most general anomalous couplings. The new features, which become especially relevant at the current stage of LHC data taking, are the simulation of gluon fusion and vector boson fusion in the off-shell region, associated ZH production at NLO QCD including the gg initial state, and the simulation of a second spin-zero resonance. We also quote translations of the anomalous coupling measurements into constraints on dimension-six operators of an effective field theory. Some of the new features are illustrated with projections for experimental measurements with the full LHC and HL-LHC datasets.
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.
In this paper, we investigate anomalous interactions of the Higgs boson with heavy fermions, employing shapes of kinematic distributions. We study the processes pp→tt¯+H, bb¯+H, tq+H, and pp→H→τ+τ− ...and present applications of event generation, reweighting techniques for fast simulation of anomalous couplings, as well as matrix element techniques for optimal sensitivity. We extend the matrix element likelihood approach (MELA) technique, which proved to be a powerful matrix element tool for Higgs boson discovery and characterization during Run I of the LHC, and implement all analysis tools in the JHU generator framework. A next-to-leading-order QCD description of the pp→tt¯+H process allows us to investigate the performance of the MELA in the presence of extra radiation. Finally, projections for LHC measurements through the end of Run III are presented.
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