Present and Future CP Measurements

We review theoretical and experimental results on CP violation summarizing the discussions in the working group on CP violation at the UK phenomenology workshop 2000 in Durham.Comment: 104 pages, Latex, to appear in Journal of Physics

LHCb Upgrade GPU High Level Trigger Technical Design Report

We present Allen, a GPU based solution for the first stage of the upgraded LHCb detector’s High Level Trigger

Computing Model of the Upgrade LHCb experiment

This document describes the computing model of the LHCb Upgrade, which will start operations in LHC Run 3. The LHCb Upgrade will have a signal yield per unit time approximately ten times higher than that of the current experiment, and pileup will increase by roughly a factor of six. However, the computing resource requirements are mitigated by the novel real-time data processing model that is being introduced and use of faster simulation techniques. Significant elements of these new strategies have already been tested, albeit at a reduced scale, in Run 2. This document presents the computing resources requirements of the LHCb Upgrade during LHC Run 3 and beyond, and the model for the utilisation of the distributed computing infrastructure available to the experiment

Upgrade Software and Computing

This document reports the Research and Development activities that are carried out in the software and computing domains in view of the upgrade of the LHCb experiment. The implementation of a full software trigger implies major changes in the core software framework, in the event data model, and in the reconstruction algorithms. The increase of the data volumes for both real and simulated datasets requires a corresponding scaling of the distributed computing infrastructure. An implementation plan in both domains is presented, together with a risk assessment analysis

Measurement of the lifetime of the Bc+ meson using the Bc+→ J/ψπ+ decay mode

The difference in total widths between the Bc+ and B+mesons is measured using a data sample corresponding to an integrated luminosity of 3.0 fb-1collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton-proton collisions at the LHC. Through the study of the time evolution of Bc+→J/ψπ+ and B+→J/ψK+decays, the width difference is measured to beδΓ≡ΓBc+-ΓB+=4.46±0.14±0.07mm-1c, where the first uncertainty is statistical and the second systematic. The known lifetime of the B+meson is used to convert this to a precise measurement of the Bc+ lifetime,τBc+=513.4±11.0±5.7fs, where the first uncertainty is statistical and the second is systematic

Determination of γ and −2βs from charmless two-body decays of beauty mesons

Using the latest LHCb measurements of time-dependent CP violation in the B-s(0) -> K+K- decay, a U-spin relation between the decay amplitudes of B-s(0) -> K+K- and B-0 -> p(+)p(-) decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B-s(0) mixing phase -2 beta(s). Results from an extended approach, which uses additional inputs on B-0 -> pi(0)pi(0) and B+ -> pi(+)pi(0) decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value gamma =( 63.5(-6.7)(+7.2))degrees modulo 180 degrees is determined. In an alternative analysis, the value -2 beta(s)= - 0.12(-0.16)(+ 0.14) rad is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included

LHCb detector performance

The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb’s unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region

Precision luminosity measurements at LHCb

Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy √ s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for √ s = 2.76, 7 and 8TeV (proton-proton collisions) and for √ sNN = 5TeV (proton-lead collisions). Both the “van der Meer scan” and “beam-gas imaging” luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at √ s = 8TeV a relative precision of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined precision of 1.12%. Applying the calibration to the full data set determines the luminosity with a precision of 1.16%. This represents the most precise luminosity measurement achieved so far at a bunched-beam hadron collider