Hadronic Charmed Meson Decays Involving Axial Vector Mesons

Cabibbo-allowed charmed meson decays into a pseudoscalar meson and an axial-vector meson are studied. The charm to axial-vector meson transition form factors are evaluated in the Isgur-Scora-Grinstein-Wise quark model. The dipole momentum dependence of the $D\to K$ transition form factor and the presence of a sizable long-distance $W$-exchange are the two key ingredients for understanding the data of $D\to \bar Ka_1$. The $K_{1A}-K_{1B}$ mixing angle of the strange axial-vector mesons is found to be $\approx \pm37^\circ$ or $\pm58^\circ$ from $\tau\to K_1\nu_\tau$ decays. The study of $D\to K_1(1270)\pi, K_1(1400)\pi$ decays excludes the positive mixing-angle solutions. It is pointed out that an observation of the decay $D^0\to K_1^-(1400)\pi^+$ at the level of $5\times 10^{-4}$ will rule out $\theta\approx -37^\circ$ and favor the solution $\theta\approx -58^\circ$. Though the decays $D^0\to \bar K_1^0\pi^0$ are color suppressed, they are comparable to and even larger than the color-allowed counterparts: $\bar K_1^0(1270)\pi^0\sim K_1^-(1270)\pi^+$ and $\bar K_1^0(1400)\pi^0> K_1^-(1400)\pi^+$. The finite width effect of the axial-vector resonance is examined. It becomes important for $a_1(1260)$ in particular when its width is near 600 MeV.Comment: 19 page

Search for long-lived neutral particles in pp collisions at s√=13 TeV that decay into displaced hadronic jets in the ATLAS calorimeter

This paper describes a search for pairs of neutral, long-lived particles decaying in the ATLAS calorimeter. Long-lived particles occur in many extensions to the Standard Model and may elude searches for new promptly decaying particles. The analysis considers neutral, long-lived scalars with masses between 5 and 400 GeV, produced from decays of heavy bosons with masses between 125 and 1000 GeV, where the long-lived scalars decay into Standard Model fermions. The analysis uses either 10.8 fb−1 or 33.0 fb−1 of data (depending on the trigger) recorded in 2016 at the LHC with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of 13 TeV. No significant excess is observed, and limits are reported on the production cross section times branching ratio as a function of the proper decay length of the long-lived particles

Replacement of missing teeth in a southern region of Vietnam--a descriptive dental laboratory study.

AIM: To explore whether tooth replacement in a southern region of Vietnam is in line with the primary health care approach, aiming at health services for all people at affordable costs. METHODS: Tooth replacement was investigated by means of prostheses as delivered by four dental laboratories of which the output was considered representative. Information was based on dental casts related to the prostheses. RESULTS: Prostheses replaced almost all missing teeth, irrespective of the types (interrupted or shortened dental arches) and numbers of missing teeth in the dental arch they were made for. Acrylic removable partial dentures were the most common prostheses delivered (65% of removable partial dentures). CONCLUSION: It cannot be stated that dental arch conditions in this study were representative for the southern Vietnamese population. However, it is concluded that dental practitioners tend to provide complete dental arches by tooth replacements. This morphologically based approach might introduce over treatment. In line with primary oral health care, a functionally oriented treatment management, including the shortened dental arch concept, should be implemented