We present a search for pair production of doubly charged Higgs bosons in the processes qq¯→H(++)H(--) decaying through H(±±)→τ(±)τ(±),μ(±)τ(±),μ(±)μ(±). The search is performed in pp¯ collisions at a center-of-mass energy of √s = 1.96 TeV using an integrated luminosity of up to 7.0 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. The results are used to set 95% C.L. limits on the pair production cross section of doubly charged Higgs bosons and on their mass for different H(±±) branching fractions. Models predicting different H(±±) decays are investigated. Assuming B(H(±±)→τ(±)τ(±))=1 yields an observed (expected) lower limit on the mass of a left-handed H(L)(±±) boson of 128 (116) GeV and assuming B(H(±±)→μ(±)τ(±))=1 the corresponding limits are 144 (149) GeV. In a model with B(H(±±)→τ(±)τ(±))=B(H(±±)→μ(±)τ(±))=B(H(±±)→μ(±)μ(±))=1/3, we obtain M(H(L)(±±))>130 (138) GeV.
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http://dx.doi.org/10.1103/PhysRevLett.108.021801 | DOI Listing |
J Chem Phys
January 2025
Volgograd State University, University Avenue 100, Volgograd 400062, Russia.
The first excited state of conjugated donor-acceptor molecules of C3 symmetry (octupolar molecules) is doubly degenerate. Such a doublet is known to be isomorphic to a spin 1/2. It is shown that a large electric dipole moment is associated with this spin.
View Article and Find Full Text PDFAnal Chem
January 2025
Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China.
Polycyclic aromatic hydrocarbons (PAHs) are pervasive environmental pollutants with significant health risks due to their carcinogenic, mutagenic, and teratogenic properties. Traditional methods for PAH identification, primarily relying on gas chromatography-mass spectrometry (GC-MS), utilize spectral library searches together with other techniques, such as mass defect analysis. However, these methods are limited by incomplete spectral libraries and a high false positive rate.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Universidade de São Paulo, Instituto de Química, Departamento de Química Fundamental, São Paulo, Brazil.
Seventeen electronic states of the dication VH were characterized by the SA-CASSCF/icMRCI methodology using very extended basis sets; 11 were described for the first time. Potential energy curves were constructed and the associated spectroscopic parameters evaluated. Triplet and quintet states correlating with the V + H channel are thermodynamic stable.
View Article and Find Full Text PDFChemistry
December 2024
Department of Applied Chemistry, Graduate School of Engineering, Mie University, Tsu, Mie, 514-8507, Japan.
A bis(triarylamine) (BTA) radical cation, bridged by two o-terphenylene moieties, was prepared and characterized to explore the impact of the double-π-bridge on the intramolecular charge/spin transfer process in the 2-site organic mixed-valence (MV) compound. Spectroscopic analyses on optically and thermally assisted intervalence charge-transfer (IVCT) processes revealed that the doubly π-bridging enhanced the charge delocalization between two nitrogen redox-active centers, whereas the electronic coupling was not so strengthened, in comparison with the singly π-bridging reference compound.
View Article and Find Full Text PDFTalanta
December 2024
State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, 430074, China. Electronic address:
Accurate in situ carbon isotopic measurements of magnesium-rich carbonates using LA-MC-ICP-MS require effective correction for isobaric interference, particularly from doubly charged Mg ions that can induce δC deviations of several permil. This study focuses on optimizing gas parameters and developing robust correction strategies to improve the accuracy of δC measurements. Experimental results demonstrate that the introduction of nitrogen gas at a flow rate of 4-6 mL/min effectively doubles signal sensitivity while optimizing low helium (0.
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