Prompt KS 0 production in pp collisions at s=0.9 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 693:2 (2010) 69-80
Abstract:
The production of KS0 mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8±1.0 μb-1. The differential prompt KS0 production cross-section is measured as a function of the KS0 transverse momentum and rapidity in the region 0Determination of the D0→K-π+π0 and D0→K-π+π+π- coherence factors and average strong-phase differences using quantum-correlated measurements
Physical Review D - Particles, Fields, Gravitation and Cosmology 80:3 (2009)
Abstract:
The first measurements of the coherence factors (RKππ0 and RK3π) and the average strong-phase differences (δDKππ0 and δDK3π) for D0→K-π+π0 and D0→K-π+π+π- are presented. These parameters can be used to improve the determination of the unitarity triangle angle γ in B-→DK- decays, where D is a D0 or D̄0 meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed D0D̄0 pairs produced in e+e- collisions at the ψ(3770) resonance. The measured values are: RKππ0=0.84±0.07, δDKππ0=(227-17+14)°, RK3π=0.33-0.23+0.20, and δDK3π=(114-23+26)°. These results indicate significant coherence in the decay D0→K-π+π0, whereas lower coherence is observed in the decay D0→K-π+π+π-. The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular, the strong-phase difference for D0→K-π+, δDKπ, and the mixing parameter y. © 2009 The American Physical Society.Search for excited quarks in ep collisions at HERA
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 678:4 (2009) 335-343
Abstract:
A search for excited quarks is performed using the full e ± p data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb - 1. The electroweak decays of excited quarks q * → q γ, q * → q Z and q * → q W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q * production cross sections and on the ratio f / Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. © 2009 Elsevier B.V.Performance of the LHCb RICH photo-detectors and readout in a system test using charged particles from a 25 ns-structured beam
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 603:3 (2009) 287-293
Abstract:
The LHCb experiment at the CERN Large Hadron Collider (LHC) utilises two Ring Imaging CHerenkov (RICH) detectors for particle identification. To verify that the RICH assembly will perform as expected prior to installation, an array of 48 production Hybrid Photon Detectors and their readout have been tested under realistic running conditions in a 25 ns-structured charged particle beam provided by the SPS facility at CERN. This system test is an important milestone in the overall commissioning of the LHCb detector and demonstrates that all aspects meet the stringent physics requirements of the LHCb experiment. © 2009 Elsevier B.V.Determination of the D0 → K- π+ π0 and D0 → K- π+ π+ π- coherence factors and average strong-phase differences using quantum-correlated measurements
PHYSICAL REVIEW D 80:3 (2009) ARTN 031105