Future of Heavy Flavour Physics: Experimental Perspective

I discuss what measurements need to be done to search for physics beyond the Standard CKM model, rather than just what studies can be done in the near future. It is also important to accurately measure the CKM matrix elements. Current best estimates for two important elements are: |V_{cb}|=0.0381 +/- 0.0021 and |V_{ub}/V_{cb}|=0.085 +/- 0.019. Finally, future experiments are discussed.Comment: Presented at "Heavy Flavours 8," Southampton, UK, July 1999, 9 pages 7 figure

Future B Experiments from The BTeV/LHC-b Perspective

Many measurements are necessary in the program of studying mixing, CP violation and rare decays of b and c quarks. These measurements require large numbers of B^o, B_s, B^- and D^{*+} hadrons. Fortunately, copius production of particles containing b and c quarks will occur at Tevatron and the LHC. The crucial measurements are described here, as well as the design of the two experiments, LHC-b and BTeV, that can exploit the 4-20 x 10^{11} b hadrons produced every 10^7 seconds.Comment: Presented at the 3rd International Conference on B Physics and CP Violation, Taipei, December 3-7, 1999 15 pages, 10 figure

The TORCH time-of-flight detector

AbstractThe TORCH time-of-flight detector is being developed to provide particle identification between 2 and 10GeV/c momentum over a flight distance of 10m. TORCH is designed for large-area coverage, up to 30m2, and has a DIRC-like construction. The goal is to achieve a 15ps time-of-flight resolution per incident particle by combining arrival times from multiple Cherenkov photons produced within quartz radiator plates of 10mm thickness. A four-year R&D programme is underway with an industrial partner (Photek, UK) to produce 53×53mm2 Micro-Channel Plate (MCP) detectors for the TORCH application. The MCP-PMT will provide a timing accuracy of 40ps per photon and it will have a lifetime of up to at least 5Ccm−2 of integrated anode charge by utilizing an Atomic Layer Deposition (ALD) coating. The MCP will be read out using charge division with customised electronics incorporating the NINO chipset. Laboratory results on prototype MCPs are presented. The construction of a prototype TORCH module and its simulated performance are also described

Observation of B0->D0K+K- and evidence for Bs0->D0K+K-

The first observation of the decay B0→D0K+K- is reported from an analysis of 0.62  fb-1 of pp collision data collected with the LHCb detector. Its branching fraction is measured relative to that of the topologically similar decay B0→D0π+π- to be B(B0→D0K+K-)/B(B0→D0π+π-)=0.056±0.011±0.007, where the first uncertainty is statistical and the second is systematic. The significance of the signal is 5.8σ. Evidence, with 3.8σ significance, for Bs0→D0K+K- decays is also presented. The relative branching fraction is measured to be B(Bs0→D0K+K-)/B(B0→D0K+K-)=0.90±0.27±0.20. These channels are of interest to study the mechanisms behind hadronic B decays, and open new possibilities for CP violation analyses with larger data sets

Observation of the decay B+c→Bºsπ+

The result of a search for the decay B+c→Bºsπ+ is presented, using the Bºs→Ds-π+ and Bºs→J/ψϕ channels. The analysis is based on a data sample of pp collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1  fb-1 taken at a center-of-mass energy of 7 TeV, and 2  fb-1 taken at 8 TeV. The decay B+c→Bºsπ+ is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [σ(Bc+)/σ(Bºs)]×B(Bc+→Bºsπ+)=[2.37±0.31 (stat)±0.11 (syst)-0.13+0.17(τBc+)]×10-3, in the pseudorapidity range 2<η(B)<5, where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the Bc+ lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction

Measurement of form-factor-independent observables in the decay B0→K*0μ+μ-

We present a measurement of form-factor-independent angular observables in the decay B0→K*(892)0μ+μ-. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0  fb-1, collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV. Four observables are measured in six bins of the dimuon invariant mass squared q2 in the range 0.1<q2<19.0  GeV2/c4. Agreement with recent theoretical predictions of the standard model is found for 23 of the 24 measurements. A local discrepancy, corresponding to 3.7 Gaussian standard deviations is observed in one q2 bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is 0.5%

Contributions to the width difference in the neutral DD system from hadronic decays

Recent studies of several multi-body $D^0$ meson decays have revealed that the final states are dominantly $CP$-even. However, the small value of the width difference between the two physical eigenstates of the $D^0$-$\overline{D}{}^0$ system indicates that the total widths of decays to $CP$-even and $CP$-odd final states should be the same to within about a percent. The known contributions to the width difference from hadronic $D^0$ decays are discussed, and it is shown that an apparent excess of quasi-$CP$-even modes is balanced, within current uncertainty, by interference effects in quasi-flavour-specific decays. Decay modes which may significantly affect the picture with improved measurements are considered.Comment: 17 pages including 3 tables. v2: Updated with published version including new comments in summar

Observation of B ̄ (s) 0 → J / ψ f 1 (1285) decays and measurement of the f 1 (1285) mixing angle

Decays of B̄s0 and B̄0 mesons into J/ψ π+π-π+π- final states, produced in pp collisions at the LHC, are investigated using data corresponding to an integrated luminosity of 3 fb-1 collected with the LHCb detector. B̄(s)0→J/ψf1(1285) decays are seen for the first time, and the branching fractions are measured. Using these rates, the f1(1285) mixing angle between strange and nonstrange components of its wave function in the qq̄ structure model is determined to be ±(24.0-2.6-0.8+3.1+0.6). Implications on the possible tetraquark nature of the f1(1285) are discussed