Updated Determination of D⁰–D¯⁰Mixing and CP Violation Parameters with D⁰→K⁺π⁻ Decays

We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D⁰→K⁺π⁻ to D⁰→K⁻π⁺ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0  fb⁻¹ recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be x′²=(3.9±2.7)×10⁻⁵, y′=(5.28±0.52)×10⁻³, and R[subscript D]=(3.454±0.031)×10⁻³. Without this assumption, the measurement is performed separately for D⁰ and D[over ¯]⁰ mesons, yielding a direct CP-violating asymmetry A[subscript D]=(-0.1±9.1)×10⁻³, and magnitude of the ratio of mixing parameters 1.00<|q/p|<1.35 at the 68.3% confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed

Search for CPCP violation through an amplitude analysis of D0→K+K−π+π−D^0 \to K^+ K^- \pi^+ \pi^- decays

International audienceA search for CP violation in the Cabibbo-suppressed D$^{0}$ → K$^{+}$K$^{−}$π$^{+}$π$^{−}$ decay mode is performed using an amplitude analysis. The measurement uses a sample of pp collisions recorded by the LHCb experiment during 2011 and 2012, corresponding to an integrated luminosity of 3.0 fb$^{−1}$. The D$^{0}$ mesons are reconstructed from semileptonic b-hadron decays into D$^{0}$μ$^{−}$X final states. The selected sample contains more than 160 000 signal decays, allowing the most precise amplitude modelling of this D$^{0}$ decay to date. The obtained amplitude model is used to perform the search for CP violation. The result is compatible with CP symmetry, with a sensitivity ranging from 1% to 15% depending on the amplitude considered

Updated determination of D 0 - D 0 mixing and C P violation parameters with D 0 → K + π -

We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D0→K+π- to D0→K-π+ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0 fb-1 recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be x′2=(3.9±2.7)×10-5, y′=(5.28±0.52)×10-3, and RD=(3.454±0.031)×10-3. Without this assumption, the measurement is performed separately for D0 and D0 mesons, yielding a direct CP-violating asymmetry AD=(-0.1±9.1)×10-3, and magnitude of the ratio of mixing parameters 1.00<|q/p|<1.35 at the 68.3% confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed

Updated determination of D-0-(D)over-bar(0) mixing and CP violation parameters with D-0 -> K+ pi(-) decays

We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of $D^0\to K^+\pi^-$ to $D^0\to K^-\pi^+$ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of $5.0$ fb$^{-1}$ recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be $x'^2=(3.9 \pm 2.7) \times10^{-5}$, $y'=(5.28 \pm 0.52) \times 10^{-3}$, and $R_D=(3.454 \pm 0.031)\times10^{-3}$. Without this assumption, the measurement is performed separately for $D^0$ and $\overline{D}{}^0$ mesons, yielding a direct CP-violating asymmetry $A_D =(-0.1\pm9.1)\times10^{-3}$, and magnitude of the ratio of mixing parameters $1.00< |q/p| <1.35$ at the $68.3\%$ confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed.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-2017-046.htm

Measurement of the Omega(0)(c) Baryon Lifetime

We report a measurement of the lifetime of the $\Omega_c^0$ baryon using proton-proton collision data at center-of-mass energies of 7 and 8~TeV, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ collected by the LHCb experiment. The sample consists of about 1000 $\Omega_b^-\to\Omega_c^0\mu^-\bar{\nu}_{\mu} X$ signal decays, where the $\Omega_c^0$ baryon is detected in the $pK^-K^-\pi^+$ final state and $X$ represents possible additional undetected particles in the decay. The $\Omega_c^0$ lifetime is measured to be $\tau_{\Omega_c^0} = 268\pm24\pm10\pm2$ fs, where the uncertainties are statistical, systematic, and from the uncertainty in the $D^+$ lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.Comment: 7 pages, 2 figures. 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-2018-028.htm

Effect of concomitant usage of alteplase and mechanical thrombectomy for M1 middle cerebral artery occlusion on clinical outcome: a retrospective analysis of 457 patients from two centers

IntroductionEndovascular thrombectomy (EVT) and concomitant usage of intravenous alteplase (alteplase) in large vessel occlusion stroke may produce unwanted excess intracerebral hemorrhage (ICH). Whether this applies specifically to isolated occlusion of the M1 segment of the middle cerebral artery (MCA) is unknown.MethodsA retrospective study from two tertiary thrombectomy centers. ICH was determined according to Heidelberg Bleeding Classification (HBC). Factors associated with the occurrence of ICH in EVT alone vs. EVT with alteplase were evaluated using logistic regression analysis. Factors related to the clinical outcome as determined with a modified Rankin scale (mRS) were investigated with univariate and adjusted multivariate logistic regression analysis. The interaction between clinical variables and the usage of alteplase on the occurrence of ICH was evaluated.ResultsAny ICH occurred in 156/457 (34.1%) patients Class 1a bleeding in 37 (8.1%), type 2 in 45 (9.8%) Class 1c in 22 (4.8%), Class 2 in 25 (5.5%), and Class 3 (extraparenchymal) in 27 (5.9%). ICH occurred in similar frequency between alteplase-treated patients vs. EVT alone (85/262 [32%] vs. 71/195 [36%]; OR 1.19 (95% CI 0.81–1.76). After adjustment, odds for clinical outcome were lower in ICH patients (OR 0.44 [95% CI 0.25–0.74]), p = 0.002). Higher ICH rate was associated with more EVT steps (p for interaction −0.005), and usage of only stent-retriever (p for interaction =0.005).ConclusionUtilization of alteplase alongside EVT for MCA M1 occlusion did not result in excessive ICH occurrences or clinical deterioration

Neutrophil to lymphocyte ratio predicts intracranial hemorrhage after endovascular thrombectomy in acute ischemic stroke

Abstract Background The development of intracranial hemorrhage (ICH) in acute ischemic stroke is associated with a higher neutrophil to lymphocyte ratio (NLR) in peripheral blood. Here, we studied whether the predictive value of NLR at admission also translates into the occurrence of hemorrhagic complications and poor functional outcome after endovascular treatment (EVT). Methods We performed a retrospective analysis of consecutive patients with anterior circulation ischemic stroke who underwent EVT at a tertiary care center from 2012 to 2016. Follow-up scans were examined for non-procedural ICH and scored according to the Heidelberg Bleeding Classification. Demographic, clinical, and laboratory data were correlated with the occurrence of non-procedural ICH. Results We identified 187 patients with a median age of 74 years (interquartile range [IQR] 60–81) and a median baseline National Institutes of Health Stroke scale (NIHSS) score of 18 (IQR 13–22). A bridging therapy with recombinant tissue-plasminogen activator (rt-PA) was performed in 133 (71%). Of the 31 patients with non-procedural ICH (16.6%), 13 (41.9%) were symptomatic. Patients with ICH more commonly had a worse outcome at 3 months (p = 0.049), and were characterized by a lower body mass index, more frequent presence of tandem occlusions, higher NLR, larger intracranial thrombus, and prolonged rt-PA and groin puncture times. In a multivariate analysis, higher admission NLR was independently associated with ICH (OR 1.09 per unit increase, 95% CI (1.00–1.20, p = 0.040). The optimal cutoff value of NLR that best distinguished the development of ICH was 3.89. Conclusions NLR is an independent predictor for the development of ICH after EVT. Further studies are needed to investigate the role of the immune system in hemorrhagic complications following EVT, and confirm the value of NLR as a potential biomarker

Higher blood pressure duringeEndovascular thrombectomy in anterior circulation stroke is associated with better outcomes

BACKGROUND AND PURPOSE: Reports investigating the relationship between in-procedure blood pressure (BP) and outcomes in patients undergoing endovascular thrombectomy (EVT) due to anterior circulation stroke are sparse and contradictory. ----- METHODS: Consecutive EVT-treated adults (modern stent retrievers, BP managed in line with the recommendations, general anesthesia, invasive BP measurements) were evaluated for associations of the rate of in-procedure systolic BP (SBP) and mean arterial pressure (MAP) excursions to >120%/<80% of the reference values (serial measurements at anesthesia induction) and of the reference BP/weighted in-procedure mean BP with post-procedure imaging outcomes (ischemic lesion volume [ILV], hemorrhages) and 3-month functional outcome (modified Rankin Scale [mRS], score 0 to 2 vs. 3 to 6). ----- RESULTS: Overall 164 patients (70.7% pharmacological reperfusion, 80.5% with good collaterals, 73.8% with successful reperfusion) were evaluated for ILV (range, 0 to 581 cm3) and hemorrhages (incidence 17.7%). Higher rate of in-procedure SBP/MAP excursions to >120% was independently associated with lower ILV, while higher in-procedure mean SBP/MAP was associated with lower odds of hemorrhages. mRS 0-2 was achieved in 75/155 (48.4%) evaluated patients (nine had missing mRS data). Higher rate of SBP/MAP excursions to >120% and higher reference SBP/MAP were independently associated with higher odds of mRS 0-2, while higher ILV was associated with lower odds of mRS 0-2. Rate of SBP/MAP excursions to <80% was not associated with any outcome. ----- CONCLUSION: s In the EVT-treated patients with BP managed within the recommended limits, a better functional outcome might be achieved by targeting in-procedure BP that exceeds the preprocedure values by more than 20%