64 research outputs found

    Quantum Isometries of the finite noncommutative geometry of the Standard Model

    Full text link
    We compute the quantum isometry group of the finite noncommutative geometry F describing the internal degrees of freedom in the Standard Model of particle physics. We show that this provides genuine quantum symmetries of the spectral triple corresponding to M x F where M is a compact spin manifold. We also prove that the bosonic and fermionic part of the spectral action are preserved by these symmetries.Comment: 29 pages, no figures v3: minor change

    First Observation of B -> D(*) rho', rho' -> omega pi-

    Full text link
    We report on the observation of B-> D(*) pi+ pi- pi- pi^o decays. The branching ratios for D*+ and D*o are (1.72+/-0.14+/-0.24)% and (1.80+/-0.24+/-0.27)%, respectively. Each final state has a D* omega pi- component, with branching ratios (0.29+/-0.03+/-0.04)% and (0.45+/-0.10+/-0.07)% for the D*+ and D*o modes, respectively. We also observe B -> D omega pi- decays. The branching ratios for D+ and Do are (0.28+/-0.05+/-0.04)% and (0.41+/-0.07+/-0.06)%, respectively. A spin parity analysis of the D omega pi- final state prefers a wide 1^- resonance. A fit to the omega pi- mass spectrum finds a central mass of (1349+/-25^{+10}_{-5}) MeV and width of (547+/-86^{+46}_{-45}) MeV. We identify this object as the rho(1450) or the \rho'.Comment: 42 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, To Appear in PR

    Resonance capture cross section of 207Pb

    Get PDF
    The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.Comment: 7 pages, 3 figures, to be published in Phys. Rev.

    Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter

    Full text link
    Azimuthal angle \Delta\phi correlations are presented for charged hadrons from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing p_T, the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed "head" region centered at Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi +/- 1.1. The p_T spectrum for the "head" region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the "shoulder" region is independent of centrality and trigger p_T, which offers constraints on energy transport mechanisms and suggests that the "shoulder" region contains the medium response to energetic jets.Comment: 420 authors from 58 institutions, 6 pages, 4 figures. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Global, regional, and national prevalence and mortality burden of sickle cell disease, 2000–2021: a systematic analysis from the Global Burden of Disease Study 2021

    Get PDF
    Background Previous global analyses, with known underdiagnosis and single cause per death attribution systems, provide only a small insight into the suspected high population health effect of sickle cell disease. Completed as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, this study delivers a comprehensive global assessment of prevalence of sickle cell disease and mortality burden by age and sex for 204 countries and territories from 2000 to 2021. Methods We estimated cause-specific sickle cell disease mortality using standardised GBD approaches, in which each death is assigned to a single underlying cause, to estimate mortality rates from the International Classification of Diseases (ICD)-coded vital registration, surveillance, and verbal autopsy data. In parallel, our goal was to estimate a more accurate account of sickle cell disease health burden using four types of epidemiological data on sickle cell disease: birth incidence, age-specific prevalence, with-condition mortality (total deaths), and excess mortality (excess deaths). Systematic reviews, supplemented with ICD-coded hospital discharge and insurance claims data, informed this modelling approach. We employed DisMod-MR 2.1 to triangulate between these measures—borrowing strength from predictive covariates and across age, time, and geography—and generated internally consistent estimates of incidence, prevalence, and mortality for three distinct genotypes of sickle cell disease: homozygous sickle cell disease and severe sickle cell β-thalassaemia, sickle-haemoglobin C disease, and mild sickle cell β-thalassaemia. Summing the three models yielded final estimates of incidence at birth, prevalence by age and sex, and total sickle cell disease mortality, the latter of which was compared directly against cause-specific mortality estimates to evaluate differences in mortality burden assessment and implications for the Sustainable Development Goals (SDGs). Findings Between 2000 and 2021, national incidence rates of sickle cell disease were relatively stable, but total births of babies with sickle cell disease increased globally by 13·7% (95% uncertainty interval 11·1–16·5), to 515 000 (425 000–614 000), primarily due to population growth in the Caribbean and western and central sub-Saharan Africa. The number of people living with sickle cell disease globally increased by 41·4% (38·3–44·9), from 5·46 million (4·62–6·45) in 2000 to 7·74 million (6·51–9·2) in 2021. We estimated 34 400 (25 000–45 200) cause-specific all-age deaths globally in 2021, but total sickle cell disease mortality burden was nearly 11-times higher at 376 000 (303 000–467 000). In children younger than 5 years, there were 81 100 (58 800–108 000) deaths, ranking total sickle cell disease mortality as 12th (compared to 40th for cause-specific sickle cell disease mortality) across all causes estimated by the GBD in 2021. Interpretation Our findings show a strikingly high contribution of sickle cell disease to all-cause mortality that is not apparent when each death is assigned to only a single cause. Sickle cell disease mortality burden is highest in children, especially in countries with the greatest under-5 mortality rates. Without comprehensive strategies to address morbidity and mortality associated with sickle cell disease, attainment of SDG 3.1, 3.2, and 3.4 is uncertain. Widespread data gaps and correspondingly high uncertainty in the estimates highlight the urgent need for routine and sustained surveillance efforts, further research to assess the contribution of conditions associated with sickle cell disease, and widespread deployment of evidence-based prevention and treatment for those with sickle cell disease.publishedVersio

    Observation of b -> d gamma and determination of vertical bar V-td/V-ts vertical bar

    Get PDF
    We report the observation of the flavor-changing neutral current process b -> d gamma using a sample of 386 x 10(6) B meson pairs accumulated by the Belle detector at the KEKB e(+)e(-) collider. We measure branching fractions for the exclusive modes B- -> rho(-)gamma, (B) over bar (0) -> rho(0)gamma, and (B) over bar (0) -> omega gamma. Assuming that these three modes are related by isospin, we find B((B) over bar -> (rho, omega)gamma) = (1.32(-0.31)(+0.34)(stat)(-0.09)(+0.10)(syst)) x 10(-6) with a significance of 5.1 sigma. This result is used to determine the ratio of Cabibbo-Kobayashi-Maskawa matrix elements vertical bar V-td/V-ts vertical bar to be 0.199(-0.025)(+0.026)(exp)(-0.015)(+0.018)(theor)

    Evidence of the purely leptonic decay B- -> tau(-)(v)over-bar(tau)

    Get PDF
    We present the first evidence of the decay B-->tau(-)nu(tau), using 414 fb(-1) of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B-->tau(-)nu(tau))=(1.79(-0.49)(+0.56)(stat)(-0.51)(+0.46)(syst))x10(-4). This implies that f(B)=0.229(-0.031)(+0.036)(stat)(-0.037)(+0.034)(syst) GeV and is the first direct measurement of this quantity

    Het Bestuursverbod bij de Commanditaire Vennootschap

    Get PDF
    Het onderwerp van dit onderzoek is de in art. 20 lid 2 WvK opgenomen regel die het de commanditaire vennoot verbiedt de commanditaire vennootschap waarin hij deelneemt te besturen. Teneinde dit onderwerp enig reliëf te geven zal ik eerst in 1.1.2 in vogelvlucht ingaan op de specifieke kenmerken van de commanditaire vennootschap en de plaats die zij inneemt in het systeem van het Nederlandse vennootschapsrecht. Daarna zal ik in 1.1.3 aandacht besteden aan de doeleinden waarvoor de commanditaire vennootschap in de rechtspraktijk wordt ingezet. In 1.1.4 bespreek ik de bezwaren die in de huidige wettelijke regeling aan deze rechtsvorm zijn verbonden. Dat leidt tot een formulering van de onderzoeksvraag in 1.1.5 en een beschrijving van het belang van het onderzoek in 1.1.6. Als laatste bespreek ik in 1.1.7 het theoretisch kader van waaruit dit onderzoek is gedaan
    corecore