Geology and mineral resources of S?o Jo?o do Para?so (RJ) region.

A regi?o de S?o Jo?o do Para?so (noroeste do Rio de Janeiro) representa um importante p?lo gerador de rochas ornamentais e de revestimento. Atualmente, s?o escassos os trabalhos que retratam as fei??es de campo, aspectos petrol?gicos e recursos minerais desta regi?o. O objetivo do presente trabalho ? apresentar os aspectos geol?gicos e recursos minerais baseados no levantamento de campo realizado e an?lises minerais por meio de estereomicrosc?pio, microsc?pio e refrat?metro. Na regi?o afloram granitoides diatex?ticos leucocr?ticos (com composi??o de plagiocl?sio, quartzo, K-feldspato, granada e biotita), m?rmores de composi??o calc?tica, paragnaisses de composi??es variadas, al?m de in?meros corpos pegmat?ticos. Tais litotipos apresentam grande potencial para o uso como rochas ornamentais e, no caso dos pegmatitos, como fonte de minerais gema, especialmente de berilo em sua variedade ?gua marinha, e de turmalina negra (shorlita).The region of S?o Jo?o do Para?so (northwest of Rio de Janeiro) is an important pole generating ornamental rocks. Currently, few works show the field features, petrological aspects and mineral resources this region. The objective of the present work is to present the geological aspects and mineral resources based on the field survey and mineral analyzes using a stereomicroscope, microscope and refractometer. In the region are exposed leucocratic diatextic granitoids (with plagioclase, quartz, K-feldspar, garnet and biotite), marbles of calcitic composition, paragnaisses of varied compositions, besides numerous pegmatitic bodies. Such lithotypes present great potential for use as ornamental rocks and, in the case of pegmatites, as a source of gem minerals, especially beryl in its aquamarine variety, and black tourmaline (shorlite)

Measurement of the lifetimes of promptly produced Ωc0Ω^{0}_{c} and Ξc0Ξ^{0}_{c} baryons

A measurement of the lifetimes of the $\Omega^{0}_{c}$ and $\Xi^{0}_{c}$ baryons is reported using proton-proton collision data at a centre-of-mass energy of $13\text{ TeV}$, corresponding to an integrated luminosity of $5.4\text{ fb}^{-1}$ collected by the LHCb experiment. The $\Omega^{0}_{c}$ and $\Xi^{0}_{c}$ baryons are produced directly from proton interactions and reconstructed in the $pK^{-}K^{-}\pi^{+}$ final state. The $\Omega^{0}_{c}$ lifetime is measured to be $276.5\pm13.4\pm4.4\pm0.7\text{ fs}$, and the $\Xi^{0}_{c}$ lifetime is measured to be $148.0\pm2.3\pm2.2\pm0.2\text{ fs}$, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the $D^{0}$ lifetime. These results confirm previous LHCb measurements based on semileptonic beauty-hadron decays, which disagree with earlier results of a four times shorter $\Omega^{0}_{c}$ lifetime, and provide the single most precise measurement of the $\Omega^{0}_{c}$ lifetime

Measurement of the lifetimes of promptly produced Omega(0)(c) and Xi(9)(c) baryons

A measurement of the lifetimes of the Omega(0)(c) and Xi(0)(c) baryons is reported using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1) collected by the LHCb experiment. The Omega(0)(c) and Xi(0)(c) baryons are produced directly from proton interactions and reconstructed in the pK(-)K(-)pi(+) final state. The Omega(0)(c) lifetime is measured to be 276.5 +/- 13.4 +/- 4.4 +/- 0.7 fs, and the Xi(0)(c) lifetime is measured to be 148.0 +/- 2.3 +/- 2.2 +/- 0.2 fs, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the D-0 lifetime. These results confirm previous LHCb measurements based on semileptonic beauty-hadron decays, which disagree with earlier results of a four times shorter Omega(c)0 lifetime, and provide the single most precise measurement of the Omega(0 )(c)lifetime. (C) 2021 Science China Press. Published by Elsevier B.V. and Science China Press