Relative Width Difference Research Articles

Measurement of the relative width difference of the B 0 ‐ B ¯ 0 $$ {B}^0\hbox{-} {\overline{B}}^0 $$ system with the ATLAS detector

This paper presents the measurement of the relative width difference $\Delta \Gamma_d / \Gamma_d$ of the $B^0$-$\bar B^0$ system using the data collected by the ATLAS experiment at the LHC in $p p$ collisions at $\sqrt{s} = 7$ TeV and $\sqrt{s} = 8$ TeV and corresponding to an integrated luminosity of 25.2 fb$^{-1}$. The value of $\Delta \Gamma_d / \Gamma_d$ is obtained by comparing the decay-time distributions of $B^0 \to J/\psi K_S$ and $B^0 \to J/\psi K^{*0}(892)$ decays. The result is $\Delta \Gamma_d / \Gamma_d = (-0.1 \pm 1.1~\mbox{(stat.)} \pm 0.9~\mbox{(syst.)}) \times 10^{-2}$. Currently, this is the most precise single measurement of $\Delta \Gamma_d / \Gamma_d$. It agrees with the Standard Model prediction and the measurements by other experiments.

Comb-like optical transmission spectra generated from one-dimensional two-segment-connected two-material waveguide networks optimized by genetic algorithm

In this Letter, a one-dimensional (1D) two-segment-connected two-material waveguide network (TSCTMWN) is designed to produce comb-like frequency passbands, where each waveguide segment is composed of normal and anomalous dispersion materials and the length ratio of sub-waveguide segments is optimized by genetic algorithm (GA). It is found that 66 comb-like frequency passbands are created in the second frequency unit, maximal relative width difference of which is less than 2 × 10 − 5 . It may be useful for the designing of dense wavelength division multiplexings (DWDMs) and multi-channel filters, etc., and provide new applications for GA. • Optical comb-like frequency bands with quasi-equal widths are created by 1D TSCTMWNs. • The maximal relative width difference of comb-like frequency bands is less than 2 × 10 − 5 . • The span, band number, and bandwidth of comb-like frequency bands can be adjusted. • GA is used for optimizing the length ratio of the sub-waveguide segments in TSCTMWNs.

Study ofCP-violating charge asymmetries of single muons and like-sign dimuons inpp¯collisions

We measure the inclusive single muon charge asymmetry and the like-sign dimuon charge asymmetry in $p \bar{p}$ collisions using the full data set of 10.4 fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron. The standard model predictions of the charge asymmetries induced by CP violation are small in magnitude compared to the current experimental precision, so non-zero measurements could indicate new sources of CP violation. The measurements differ from the standard model predictions of CP violation in these asymmetries with a significance of 3.6 standard deviations. These results are interpreted in a framework of $B$ meson mixing within the CKM formalism to measure the relative width difference $\dgg$ between the mass eigenstates of the $\Bd$ meson system, and the semileptonic charge asymmetries $\asld$ and $\asls$ of $\Bd$ and $\Bs$ mesons respectively.

Measurement of the Lifetime Difference in theBs0System

We present a study of the decay Bs0→J/ψϕ. We obtain the CP-odd fraction in the final state at time zero, R⊥=0.16±0.10(stat)±0.02(syst), the average lifetime of the (Bs0, B¯s0) system, τ¯(Bs0)=1.39−0.16+0.13(stat)−0.02+0.01(syst) ps, and the relative width difference between the heavy and light mass eigenstates, ΔΓ/Γ¯≡(ΓL−ΓH)/Γ¯=0.24−0.38+0.28(stat)−0.04+0.03(syst). With the additional constraint from the world average of the Bs0 lifetime measurements using semileptonic decays, we find τ¯(Bs0)=1.39±0.06 ps and ΔΓ/Γ¯=0.25−0.15+0.14. For the ratio of the Bs0 and B0 lifetimes we obtain τ¯(Bs0)τ(B0)=0.91±0.09(stat)±0.003(syst).Received 20 July 2005DOI:https://doi.org/10.1103/PhysRevLett.95.171801©2005 American Physical Society

MORPHOLOGICAL DIFFERENTIATION BETWEEN ADJACENT POPULATIONS OF ASIATIC BLACK BEARS, URSUS THIBETANUS JAPONICUS, IN NORTHERN JAPAN

The skull morphology of black bears inhabiting 2 distributional ranges isolated by 2 river basins in northern Japan was compared in order to examine whether the animals represent different populations. We found substantial differences in relative width of the skull and measurements related to the masticatory apparatus, especially in the length of the molar row and palatal width; the former already differs at 1 year of age when the eruption of permanent teeth occurs, suggesting a genetic basis for the difference. Jackknifed classification was able to correctly assign all adult specimens except 1. The results indicate that bears from these 2 areas belong to different populations that might have been isolated for a considerable period, and gene flow between them is limited, even though the distance between the 2 ranges is only several kilometers at the narrowest point. The Japanese black bear might live in small, isolated local populations.

Heavy quark phenomenology from lattice QCD

Recent results relevant for the B-physics phenomenology, obtained from lattice QCD simulations by the APE Collaboration, are reviewed. This includes the B 0 - B 0 mixing amplitude, B → π semileptonic decay and the relative width difference of B 0 s mesons, (ΔΓ/Γ) B s .