180 research outputs found
Intracranial bleeding due to vitamin K deficiency: advantages of using a pediatric intensive care registry
Item does not contain fulltextAIM: To determine the incidence of late intracranial vitamin K deficiency bleeding (VKDB) in The Netherlands using the Dutch Pediatric Intensive Care Evaluation (PICE) registry. METHODS: The PICE registry was used to identify all infants who were admitted to a Dutch pediatric intensive care unit (PICU) with intracranial bleeding between 1 January 2004 and 31 December 2007. Cases of confirmed late intracranial VKDB were used to calculate the incidence for each year. To estimate the completeness of ascertainment of the PICE registry, data from 2005 were compared with general surveillance data from that year. RESULTS: In the 4-year study period, 16/64 (25%) of the infants admitted with intracranial bleeding had late intracranial VKDB, resulting in an overall incidence of 2.1/100,000 live births (95% confidence interval 1.2-3.5). The single-year incidence varied markedly between 0.5 and 3.3 per 100,000 live births. All five ascertained cases in 2005 were identified using the PICE registry, while general surveillance identified only three. CONCLUSIONS: The PICE registry allows ongoing monitoring of the incidence of late intracranial VKDB and appears to be associated with a higher rate of completeness than general surveillance. We propose the use of pediatric intensive care registries to assess the efficacy of national vitamin K prophylactic regimens
Observation of Two New Excited Îb0 States Decaying to Îb0 K-Ï+
Two narrow resonant states are observed in the Îb0K-Ï+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb-1. The minimal quark content of the Îb0K-Ï+ system indicates that these are excited Îb0 baryons. The masses of the Îb(6327)0 and Îb(6333)0 states are m[Îb(6327)0]=6327.28-0.21+0.23±0.12±0.24 and m[Îb(6333)0]=6332.69-0.18+0.17±0.03±0.22 MeV, respectively, with a mass splitting of Îm=5.41-0.27+0.26±0.12 MeV, where the uncertainties are statistical, systematic, and due to the Îb0 mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Î[Îb(6327)0]<2.20(2.56) and Î[Îb(6333)0]<1.60(1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Îb0 resonances
Measurement of D s <sup>±</sup> production asymmetry in pp collisions at âs=7 and 8 TeV
The inclusive production asymmetry is measured in collisions
collected by the LHCb experiment at centre-of-mass energies of
and 8 TeV. Promptly produced mesons are used, which decay as
, with . The measurement is
performed in bins of transverse momentum, , and rapidity, ,
covering the range GeV and . No kinematic
dependence is observed. Evidence of nonzero production asymmetry is
found with a significance of 3.3 standard deviations.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2018-010.htm
Search for CP violation in Îb0âpKâ and Îb0âpÏâ decays
A search for CP violation in Îb0âpKâ and Îb0âpÏâ decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fbâ1. The CP -violating asymmetries are measured to be ACPpKâ=â0.020±0.013±0.019 and ACPpÏâ=â0.035±0.017±0.020, and their difference ACPpKââACPpÏâ=0.014±0.022±0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date
Precision measurement of violation in the penguin-mediated decay
A flavor-tagged time-dependent angular analysis of the decay
is performed using collision data collected
by the LHCb experiment at % at TeV, the center-of-mass energy of
13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The
-violating phase and direct -violation parameter are measured
to be rad and
, respectively, assuming the same values
for all polarization states of the system. In these results, the
first uncertainties are statistical and the second systematic. These parameters
are also determined separately for each polarization state, showing no evidence
for polarization dependence. The results are combined with previous LHCb
measurements using collisions at center-of-mass energies of 7 and 8 TeV,
yielding rad and . This is the most precise study of time-dependent violation
in a penguin-dominated meson decay. The results are consistent with
symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb
public pages
Measurement of the differential branching fraction
The branching fraction of the rare decay is measured for the first time, in the squared dimuon mass
intervals, , excluding the and regions. The data
sample analyzed was collected by the LHCb experiment at center-of-mass energies
of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\
\mathrm{fb}^{-1}q^{2}q^{2} >15.0\
\mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model
dependence, agrees with the predictions.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-050.html (LHCb
public pages
Measurement of the CKM angle using with decays
A model-dependent amplitude analysis of the decay is performed using proton-proton collision data
corresponding to an integrated luminosity of 3.0fb, recorded at
and by the LHCb experiment. The CP violation observables
and , sensitive to the CKM angle , are measured to
be \begin{eqnarray*} x_- &=& -0.15 \pm 0.14 \pm 0.03 \pm 0.01, y_- &=& 0.25 \pm
0.15 \pm 0.06 \pm 0.01, x_+ &=& 0.05 \pm 0.24 \pm 0.04 \pm 0.01, y_+ &=&
-0.65^{+0.24}_{-0.23} \pm 0.08 \pm 0.01, \end{eqnarray*} where the first
uncertainties are statistical, the second systematic and the third arise from
the uncertainty on the amplitude model. These
are the most precise measurements of these observables. They correspond to
and , where is
the magnitude of the ratio of the suppressed and favoured decay amplitudes, in a mass region of around the
mass and for an absolute value of the cosine of the decay
angle larger than .Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-007.htm
Model-independent measurement of mixing parameters in D0ââ K S 0 Ï+Ïâ decays
The first model-independent measurement of the charm mixing parameters in the decay D 0âââK S 0 Ï + Ï â is reported, using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fbâ1 at a centre-of-mass energy of 7 TeV. The measured values are
x=(â0.86±0.53±0.17)Ă10â2,y=(+0.03±0.46±0.13)Ă10â2,
x=(â0.86±0.53±0.17)Ă10â2,y=(+0.03±0.46±0.13)Ă10â2,
where the first uncertainties are statistical and include small contributions due to the external input for the strong phase measured by the CLEO collaboration, and the second uncertainties are systematic
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