Abstract The time-dependent CP asymmetries of B 0 → π + π − and B s 0 $$ {B}_s^0 $$ → K + K − decays are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 ...fb −1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. The results are C ππ = − 0.311 ± 0.045 ± 0.015 , S ππ = − 0.706 ± 0.042 ± 0.013 , C KK = 0.123 ± 0.034 ± 0.015 , S KK = 0.164 ± 0.034 ± 0.014 , A KK Δ Γ = − 0.83 ± 0.05 ± 0.09 , $$ {\displaystyle \begin{array}{c}{C}_{\pi \pi}=-0.311\pm 0.045\pm 0.015,\\ {}{S}_{\pi \pi}=-0.706\pm 0.042\pm 0.013,\\ {}{C}_{KK}=0.123\pm 0.034\pm 0.015,\\ {}{S}_{KK}=0.164\pm 0.034\pm 0.014,\\ {}{\mathcal{A}}_{KK}^{\Delta \varGamma }=-0.83\pm 0.05\pm 0.09,\end{array}} $$ where the first uncertainties are statistical and the second systematic. The same data sample is used to measure the time-integrated CP asymmetries of B 0 → K + π − and B s 0 $$ {B}_s^0 $$ → K − π + decays and the results are A CP B 0 = − 0.0824 ± 0.0033 ± 0.0033 , A CP B s 0 = 0.236 ± 0.013 ± 0.011 . $$ {\displaystyle \begin{array}{c}{A}_{CP}^{B^0}=-0.0824\pm 0.0033\pm 0.0033,\\ {}{A}_{CP}^{B_s^0}=0.236\pm 0.013\pm 0.011.\end{array}} $$ All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in B s 0 $$ {B}_s^0 $$ decays.
Abstract A search for the B s 0 $$ {B}_{\mathrm{s}}^0 $$ → D *± D ∓ decay is performed using proton-proton collision data at centre-of-mass energies of 7, 8 and 13 TeV collected by the LHCb ...experiment, corresponding to an integrated luminosity of 9 fb −1. The decay is observed with a high significance and its branching fraction relative to the B 0 → D *± D ∓ decay is measured to be ℬ B s 0 → D ∗ ± D ∓ B 0 → D ∗ ± D ∓ = 0.137 ± 0.017 ± 0.002 ± 0.006 , $$ \frac{\mathrm{\mathcal{B}}\left({B}_s^0\to {D}^{\ast \pm }{D}^{\mp}\right)}{\left({B}^0\to {D}^{\ast \pm }{D}^{\mp}\right)}=0.137\pm 0.017\pm 0.002\pm 0.006, $$ where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the B s 0 $$ {B}_{\mathrm{s}}^0 $$ and B 0 hadronisation fractions.
Abstract The CKM angle γ is measured for the first time from mixing-induced CP violation between B s 0 → D s ∓ K ± π ± π ∓ $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm }{\pi}^{\pm }{\pi}^{\mp } $$ and B ¯ s 0 ...→ D s ± K ∓ π ∓ π ± $$ {\overline{B}}_s^0\to {D}_s^{\pm }{K}^{\mp }{\pi}^{\mp }{\pi}^{\pm } $$ decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb −1 recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the CP-violating weak phase γ − 2β s and, subsequently, γ by taking the B s 0 ‐ B ¯ s 0 $$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$ mixing phase β s as an external input. The measurement yields γ = (44 ± 12)° modulo 180°, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields γ = 44 − 13 + 20 ° $$ \gamma =\left({44}_{-13}^{+20}\right){}^{\circ} $$ modulo 180°. Moreover, the B s 0 ‐ B ¯ s 0 $$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$ oscillation frequency is measured from the flavour-specific control channel B s 0 → D s − π + π + π − $$ {B}_s^0\to {D}_s^{-}{\pi}^{+}{\pi}^{+}{\pi}^{-} $$ to be ∆m s = (17.757 ± 0.007(stat) ± 0.008(syst)) ps −1, consistent with and more precise than the current world-average value.
At the beginning of the COVID-19 pandemic, health workers and first-responders, such as police officers, were in charge of trying to contain a disease that was unknown at that time. The lack of ...information and the tremendous need to contain new outbreaks put police officers at higher risk.
A cross-sectional study was conducted to describe SARS-CoV-2 infection rates among Police Special Forces Officers in Quito, Ecuador. In this study, 163 community-dwelling police officers from elite divisions voluntarily participated in our SARS-CoV-2 detection program using reverse transcription quantitative real-time PCR (RT-qPCR).
A total of 20 out of 163 police officers tested positive for SARS-CoV-2, yielding an infection rate of 12.3%. Within this cohort, 10% (2/20) of SARS-CoV-2 positive individuals were potentially super spreaders with viral loads over 10
copies/ul. About 85% of the SARS-CoV-2 positive individuals were asymptomatic and 15% reported mild symptoms related to COVID-19.
We found a high SARS-CoV-2 infection rate within the special forces police officers that, beyond a high health risk for themselves, their families, and coworkers. Our results point out the need for permanent SARS-CoV-2 testing among asymptomatic essential workers and first-responders to avoid local outbreaks and to prevent work-place absenteeism among police special units.
The major low molecular weight hordein (LMW hordein-1) from barley has been purified by preparative two-dimensional gel electrophoresis. Both its molecular weight (16500) and its amino acid ...composition are very close to those reported for LMW gliadins from wheat and A-secalins from rye. LMW hordein-1 lacks lysine and histidine and has a higher proportion of sulfur amino acids and a lower one of proline than B- and C-hordeins. The values of the compositional difference index determined for binary comparisons between the purified protein and other low molecular weight prolamins are consistent with a high degree of sequence homology between LMW hordein-1 and individual components of LMW gliadins and A-secalins but do not show homology with the sulfur-rich zeins.
Abstract The inclusive b b ¯ $$ b\overline{b} $$ - and c c ¯ $$ c\overline{c} $$ -dijet production cross-sections in the forward region of pp collisions are measured using a data sample collected ...with the LHCb detector at a centre-of-mass energy of 13 TeV in 2016. The data sample corresponds to an integrated luminosity of 1.6 fb −1. Differential cross-sections are measured as a function of the transverse momentum and of the pseudorapidity of the leading jet, of the rapidity difference between the jets, and of the dijet invariant mass. A fiducial region for the measurement is defined by requiring that the two jets originating from the two b or c quarks are emitted with transverse momentum greater than 20 GeV/c, pseudorapidity in the range 2.2 < η < 4.2, and with a difference in the azimuthal angle between the two jets greater than 1.5. The integrated b b ¯ $$ b\overline{b} $$ -dijet cross-section is measured to be 53.0 ± 9.7 nb, and the total c c ¯ $$ c\overline{c} $$ -dijet cross-section is measured to be 73 ± 16 nb. The ratio between c c ¯ $$ c\overline{c} $$ - and b b ¯ $$ b\overline{b} $$ -dijet cross-sections is also measured and found to be 1.37 ± 0.27. The results are in agreement with theoretical predictions at next-to-leading order.
Abstract The decays B s 0 $$ {\mathrm{B}}_{\mathrm{s}}^0 $$ → J/ψπ+π − K+K − are studied using a data set corresponding to an integrated luminosity of 9 fb −1, collected with the LHCb detector in ...proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays B s 0 $$ {\mathrm{B}}_{\mathrm{s}}^0 $$ → J / ψK ∗ 0 K ¯ ∗ 0 $$ \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0} $$ and B s 0 $$ {\mathrm{B}}_{\mathrm{s}}^0 $$ → χc1(3872)K+K − , where the K+K − pair does not originate from a ϕ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate χc1(3872)ϕ, J / ψK ∗ 0 K ¯ ∗ 0 $$ \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0} $$ , ψ(2S)ϕ and χc1(3872)K+K − states are reported. A structure, denoted as X(4740), is observed in the J/ψϕ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be m X 4740 = 4741 ± 6 ± 6 MeV / c 2 , Γ X 4740 = 53 ± 15 ± 11 MeV , $$ {\displaystyle \begin{array}{c}{m}_{\mathrm{X}(4740)}=4741\pm 6\pm 6\kern0.5em \mathrm{MeV}/{c}^2,\\ {}{\Gamma}_{\mathrm{X}(4740)}=53\pm 15\pm 11\kern0.5em \mathrm{MeV},\end{array}} $$ where the first uncertainty is statistical and the second is systematic. In addition, the most precise single measurement of the mass of the B s 0 $$ {\mathrm{B}}_{\mathrm{s}}^0 $$ meson is performed and gives a value of m B s 0 = 5366.98 ± 0.07 ± 0.13 MeV / c 2 . $$ {m}_{{\mathrm{B}}_{\mathrm{s}}^0}=5366.98\pm 0.07\pm 0.13\kern0.5em \mathrm{MeV}/{c}^2. $$
Abstract A measurement of CP-violating observables is performed using the decays B ± → DK ± and B ± → Dπ ±, where the D meson is reconstructed in one of the self-conjugate three-body final states K S ...0 $$ {K}_{\mathrm{S}}^0 $$ π + π − and K S 0 $$ {K}_{\mathrm{S}}^0 $$ K + K − (commonly denoted K S 0 $$ {K}_{\mathrm{S}}^0 $$ h + h − ). The decays are analysed in bins of the D-decay phase space, leading to a measurement that is independent of the modelling of the D-decay amplitude. The observables are inter- preted in terms of the CKM angle γ. Using a data sample corresponding to an integrated luminosity of 9 fb −1 collected in proton-proton collisions at centre-of mass energies of 7, 8, and 13 TeV with the LHCb experiment, γ is measured to be 68.7 − 5.1 + 5.2 ° $$ \left({68.7}_{-5.1}^{+5.2}\right){}^{\circ} $$ . The hadronic parameters r B DK , r B Dπ , δ B DK , and δ B Dπ $$ {r}_B^{D K},{r}_B^{D\pi},{\delta}_B^{D K},\kern0.5em \mathrm{and}\kern0.5em {\delta}_B^{D\pi} $$ , which are the ratios and strong-phase differences of the suppressed and favoured B ± decays, are also reported.
Abstract An angular analysis of the B 0 → K* 0 e + e − decay is performed using a data sample corresponding to an integrated luminosity of 9 fb −1 of pp collisions collected with the LHCb experiment. ...The analysis is conducted in the very low dielectron mass squared (q 2) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B 0 → K *0 γ transition with a virtual photon. The fraction of longitudinal polarisation of the K *0 meson, F L, is measured to be F L = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The A T Re $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ observable, which is related to the lepton forward-backward asymmetry, is measured to be A T Re $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ = −0.06 ± 0.08 ± 0.02. The A T 2 $$ {A}_{\mathrm{T}}^{(2)} $$ and A T Im $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be A T 2 $$ {A}_{\mathrm{T}}^{(2)} $$ = 0.11 ± 0.10 ± 0.02 and A T Im $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world’s best constraint on the b → sγ photon polarisation.
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