L. Jones

Seismic isolation enhancements for initial and Advanced LIGO

A seismic isolation system for the proposed Advanced LIGO detector upgrade is under development. It consists of a two-stage in-vacuum active isolation platform that is supported by an external hydraulic actuation stage. A full-scale preliminary-design technology demonstrator of the in-vacuum platform has been assembled and is being tested at Stanfords engineering test facility. Unanticipated excess ground motion from local human activity at LIGO Livingston has prompted accelerated development of the external stage for installation and use in the initial Livingston detector. As an interim measure, active external isolation in the laser beam direction is implemented using existing PZT external actuators.

Measurement of the branching fraction of [Formula presented] inclusive semileptonic decay [Formula presented]

The absolute inclusive semileptonic branching fraction of the D{sub s} meson has been measured based on 22.3 pb{sup {minus}1} of e{sup +}e{sup {minus}} collision data collected with the Beijing Spectrometer at {radical} (s) =4.03GeV. At this energy, the D{sub s} are produced in pairs: e{sup +}e{sup {minus}}{r_arrow}D{sub s}{sup +}D{sub s}{sup {minus}}. We reconstructed 171{plus_minus}21{plus_minus}15 D{sub s} events in five hadronic decay modes. In the recoil system of these events, several D{sub s} inclusive semileptonic decays were observed and the branching fraction is estimated to be B(D{sub s}{sup +}{r_arrow}e{sup +}X)=(7.7{sub {minus}4.3{minus}2.1}{sup +5.7+2.4}){percent}. {copyright} {ital 1997} {ital The American Physical Society}Author(s): Bai, JZ; Bardon, O; Bian, JG; Blum, I; Breakstone, A; Burnett, T; Chai, ZW; Chen, GP; Chen, HF; Chen, J; Chen, JC; Chen, SM; Chen, Y; Chen, YB; Chen, YQ; Cheng, BS; Cowan, RF; Cui, XZ; Ding, HL; Du, ZZ; Dunwoodie, W; Fan, XL; Fang, J; Fero, M; Gao, CS; Gao, ML; Gao, SQ; Gratton, P; Gu, JH; Gu, SD; Gu, WX; Gu, YF; Guo, YN; Han, SW; Han, Y; Harris, FA; He, J; He, JT; He, M; Hitlin, DG; Hu, GY; Hu, JL; Hu, QH; Hu, T; Hu, XQ; Huang, XP; Huang, YZ; Izen, JM; Jia, QP; Jiang, CH; Jin, S; Jin, Y; Jones, L; Kang, SH; Ke, ZJ; Kelsey, MH; Kim, BK; Kong, D; Lai, YF; Lan, HB; Lang, PF; Lankford, A; Li, J; Li, PQ; Li, Q; Li, RB; Li, W; Li, WD; Li, WG; Li, XH; Li, XN; Lin, SZ; Lu, F; Liu, HM; Liu, J; Liu, JH; Liu, Q; Liu, RG; Liu, Y; Liu, ZA; Lou, XC; Lowery, B; Lu, JG; Lu, JY; Luo, SQ | Abstract: The absolute inclusive semileptonic branching fraction of the [Formula presented] meson has been measured based on [Formula presented] of [Formula presented] collision data collected with the Beijing Spectrometer at [Formula presented] At this energy, the [Formula presented] are produced in pairs: [Formula presented] We reconstructed [Formula presented] [Formula presented] events in five hadronic decay modes. In the recoil system of these events, several [Formula presented] inclusive semileptonic decays were observed and the branching fraction is estimated to be [Formula presented]

Direct measurement of the D_s branching fraction to φπ

The Beijing Spectrometer (BES) Collaboration has observed exclusive pair production of {ital D}{sub {ital s}} mesons at the Beijing Electron-Positron Collider (BEPC) at a center-of-mass energy of 4.03 GeV. The {ital D}{sub {ital s}} mesons are detected in the {phi}{pi}{sup +}, {ital {bar K}} {sup *0}{ital K}{sup +}, and {ital {bar K}} {sup 0}{ital K}{sup +} decay modes; two fully reconstructed events yield the value (3.9{sub {minus}1.9{minus}1.1}{sup +5.1+1.8})% for the {ital D}{sub {ital s}} branching fraction to {phi}{pi}. This is the first direct, model-independent measurement of this quantity.