Measurements of CP violation in B mixing through B→J/ψXB \to J/\psi X decays at LHCb

B mesons provide an ideal laboratory for measurements of CP violation and searches for CP violation beyond the Standard Model. Recent measurements of the mixing phases of the $B_s^0$ and $B^0$ mesons, $\phi_s$ and $\sin2\beta$, using decays to $J/\psi X$ final states are presented. In view of future improved measurements, a good understanding of pollution from sub-leading penguin topologies in these decays is needed. Those can be probed using suppressed decays like $B_s^0 \to J/\psi K_S^0$ and $B_s^0 \to J/\psi \overline{K}^{*0}$. Recent results using these decay modes are presented.Comment: Proceedings for EPS-HEP 2015. Updated introductio

Tetraquarks and pentaquarks

Greig Cowan and Tim Gershon describe new types of matter called tetraquarks and pentaquarks, and discuss the outlook for understanding these particles.Comment: Published as a Physics World Discovery eBook, by IoP Publishing, 2018. Available online at http://iopscience.iop.org/book/978-0-7503-1593-7, IoP Publishing 2018. ISBN: 978-0-7503-1593-

Optimised access to user analysis data using the gLite DPM

The ScotGrid distributed Tier-2 now provides more that 4MSI2K and 500TB for LHC computing, which is spread across three sites at Durham, Edinburgh and Glasgow. Tier-2 sites have a dual role to play in the computing models of the LHC VOs. Firstly, their CPU resources are used for the generation of Monte Carlo event data. Secondly, the end user analysis data is distributed across the grid to the site's storage system and held on disk ready for processing by physicists' analysis jobs. In this paper we show how we have designed the ScotGrid storage and data management resources in order to optimise access by physicists to LHC data. Within ScotGrid, all sites use the gLite DPM storage manager middleware. Using the EGEE grid to submit real ATLAS analysis code to process VO data stored on the ScotGrid sites, we present an analysis of the performance of the architecture at one site, and procedures that may be undertaken to improve such. The results will be presented from the point of view of the end user (in terms of number of events processed/second) and from the point of view of the site, which wishes to minimise load and the impact that analysis activity has on other users of the system

Determination of 2beta_s in B_s -> J/psi K^+ K^- Decays in the Presence of a K^+K^- S-Wave Contribution

We present the complete differential decay rates for the process B_s -> J/psi K^+ K^- including S-wave and P-wave angular momentum states for the K^+ K^- meson pair. We examine the effect of an S-wave component on the determination of the CP violating phase 2beta_s. Data from the B-factories indicate that an S-wave component of about 10% may be expected in the phi(1020) resonance region. We find that if this contribution is ignored in the analysis it could cause a bias in the measured value of 2beta_s towards zero of the order of 10%. When including the K^+K^- S-wave component we observe an increase in the statistical error on 2beta_s by less than 15%. We also point out the possibility of measuring the sign of cos2beta_s by using the interference between the K^+K^- S-wave and P-wave amplitudes to resolve the strong phase ambiguity. We conclude that the S-wave component can be properly taken into account in the analysis.Comment: 11 pages, 6 figure