The decay $overline{B}_s^0 rightarrow psi(2S) K^+ pi^-$ is observed using a data set corresponding to an integrated luminosity of $3.0fb^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The branchin
g fraction relative to the $B^0rightarrow psi(2S) K^+ pi^-$ decay mode is measured to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^+ pi^-)}{{cal B}(B^0 rightarrow psi(2S) K^+ pi^-)} = 5.38 pm 0.36 (stat) pm 0.22 (syst) pm 0.31 , (f_s/f_d) , %, onumber end{equation} where $f_s/f_d$ indicates the uncertainty due to the ratio of probabilities for a $b$ quark to hadronise into a $B_s^0$ or $B^0$ meson. Using an amplitude analysis, the fraction of decays proceeding via an intermediate $K^*(892)^0$ meson is measured to be $0.645 pm 0.049 (stat) pm 0.049 (syst)$ and its longitudinal polarisation fraction is $0.524 pm 0.056 (stat) pm 0.029 (syst)$. The relative branching fraction for this component is determined to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^*(892)^0)}{{cal B}(B^0 rightarrow psi(2S) K^*(892)^0)} = 5.58 pm 0.57 (stat) pm 0.40 (syst) pm 0.32 , (f_s/f_d) , %. onumber end{equation} In addition, the mass splitting between the $B_s^0$ and $B^0$ mesons is measured as begin{equation} M(B^0_s) - M(B^0) = 87.45 pm 0.44 (stat) pm 0.07 (syst) MeV/c^2. onumber end{equation}
The time-dependent $CP$ asymmetry in $B_s^0 to J/psi K^+K^-$ decays is measured using $pp$ collision data, corresponding to an integrated luminosity of $3.0$fb$^{-1}$, collected with the LHCb detector at centre-of-mass energies of $7$ and $8$TeV. In
a sample of 96 000 $B_s^0 to J/psi K^+K^-$ decays, the $CP$-violating phase $phi_s$ is measured, as well as the decay widths $Gamma_{L}$ and $Gamma_{H}$ of the light and heavy mass eigenstates of the $B_s^0-bar{B}_s^0$ system. The values obtained are $phi_s = -0.058 pm 0.049 pm 0.006$ rad, $Gamma_s equiv (Gamma_{L}+Gamma_{H})/2 = 0.6603 pm 0.0027 pm 0.0015$ps$^{-1}$, and$DeltaGamma_s equiv Gamma_{L} - Gamma_{H} = 0.0805 pm 0.0091 pm 0.0032$ps$^{-1}$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of those quantities to date. A combined analysis with $B_s^{0} to J/psi pi^+pi^-$ decays gives $phi_s = -0.010 pm 0.039 $rad. All measurements are in agreement with the Standard Model predictions. For the first time the phase $phi_s$ is measured independently for each polarisation state of the $K^+K^- $ system and shows no evidence for polarisation dependence.
Measurements of $b$-hadron lifetimes are reported using $pp$ collision data, corresponding to an integrated luminosity of 1.0fb$^{-1}$, collected by the LHCb detector at a centre-of-mass energy of $7$Tev. Using the exclusive decays $B^+to J/psi K^+$,
$B^0to J/psi K^*(892)^0$, $B^0to J/psi K^0_{rm S}$, $Lambda_b^0to J/psi Lambda$ and $B^0_sto J/psi phi$ the average decay times in these modes are measured to be $tau_{B^+to J/psi K^+}$ = $1.637 pm$ 0.004 $pm$ 0.003 ps, $tau_{B^0to J/psi K^*(892)^0}$ = $1.524 pm$ 0.006 $pm$ 0.004 ps, $tau_{B^0to J/psi K^0_{rm S}}$ = $1.499 pm$ 0.013 $pm$ 0.005 ps, $tau_{Lambda_b^0to J/psi Lambda}$ = $1.415 pm$ 0.027 $pm$ 0.006 ps and $tau_{B^0_sto J/psi phi}$ = $1.480 pm$ 0.011 $pm$ 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, $DeltaGamma_d$, to the average width, $Gamma_d$, in the $B^0$ system, $Delta Gamma_d/Gamma_d = -0.044 pm 0.025 pm 0.011$, are reported. All quantities are found to be consistent with Standard Model expectations.
The time-dependent CP asymmetry in B_s^0to J/psi K^+K^- decays is measured using $pp$ collision data at sqrt{s}=7TeV, corresponding to an integrated luminosity of 1.0fb^-1, collected with the LHCb detector. The decay time distribution is characterise
d by the decay widths Gamma_L and Gamma_H of the light and heavy mass eigenstates of the B_s^0--bar{B}_s^0 system and by a CP-violating phase phi_s. In a sample of 27,617 B_s^0to J/psi K^+K^- decays, where the dominant contribution comes from B_s^0to J/psiphi decays, these parameters are measured to be phi_s = 0.07 pm 0.09 (stat) pm 0.01 (syst) rad, Gamma_s equiv (Gamma_L+Gamma_H)/2 = 0.663 pm 0.005 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s equiv Gamma_L -Gamma_H = 0.100 pm 0.016 (stat) pm 0.003 (syst) & ps^-1, corresponding to the single most precise determination of phi_s, DeltaGamma_s and Gamma_s. The result of performing a combined analysis with B_s^{0} to J/psi pi^+pi^- decays gives phi_s = 0.01 pm 0.07 (stat) pm 0.01 (syst) rad, Gamma_s = 0.661 pm 0.004 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s = 0.106 pm 0.011 (stat) pm 0.007 (syst) & ps^-1. All measurements are in agreement with the Standard Model predictions.
The start of data taking at the Large Hadron Collider will herald a new era in data volumes and distributed processing in particle physics. Data volumes of hundreds of Terabytes will be shipped to Tier-2 centres for analysis by the LHC experiments us
ing the Worldwide LHC Computing Grid (WLCG). In many countries Tier-2 centres are distributed between a number of institutes, e.g., the geographically spread Tier-2s of GridPP in the UK. This presents a number of challenges for experiments to utilise these centres efficaciously, as CPU and storage resources may be sub-divided and exposed in smaller units than the experiment would ideally want to work with. In addition, unhelpful mismatches between storage and CPU at the individual centres may be seen, which make efficient exploitation of a Tier-2s resources difficult. One method of addressing this is to unify the storage across a distributed Tier-2, presenting the centres aggregated storage as a single system. This greatly simplifies data management for the VO, which then can access a greater amount of data across the Tier-2. However, such an approach will lead to scenarios where analysis jobs on one sites batch system must access data hosted on another site. We investigate this situation using the Glasgow and Edinburgh clusters, which are part of the ScotGrid distributed Tier-2. In particular we look at how to mitigate the problems associated with ``distant data access and discuss the security implications of having LAN access protocols traverse the WAN between centres.
