Search

Abstract: The branching fraction is measured in a data sample corresponding to of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the measurement from . The time-integrated branching fraction is measured to be . This is the most precise measurement to date. [Copyright &y& Elsevier]

The question if the Bose statistics is broken at the TeV scale is discussed. The decay of a new heavy spin-1 gauge boson Z′ into two photons, Z′ → γγ, is forbidden by the Bose statistics among other general principles of quantum field theory (Landau-Yang theorem). We point out that the search for this decay can be effectively used to probe the Bose symmetry violation at the CERN LHC. [ABSTRACT FROM AUTHOR]

We investigate a squark cascade decay, i.e. $\tilde q_L \rightarrow q\tilde\chi_2^0\rightarrow q Z\tilde\chi_1^0 \rightarrow qll\tilde\chi_1^0$. It is shown that some information on the mass and spin of the supersymmetric particles might be obtained from the cascade decay chain at the Large Hadron Collider at CERN. [ABSTRACT FROM AUTHOR]

Abstract: A search for the decays and is performed with about of pp collisions at collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are and at 95% confidence level. [Copyright &y& Elsevier]

Abstract: The LHCb experiment will search for new physics in CP violation and rare decays from heavy flavour production at the LHC. Particle identification is provided by two Ring Imaging Cherenkov (RICH) detectors, which incorporate a total of 484 Hybrid Photon Detectors (HPDs). The RICH detectors are located in the fringe field of the LHCb dipole magnet and fields as large as 2.5mT have been measured in some regions occupied by the RICH 1 photodetectors. It is necessary to make corrections for the distortion of the ring-images measured by the HPDs. RICH 1 incorporates a magnetic calibration system comprising a series of collimated LEDs mounted on x–y stages which scan over the front-faces of the HPD arrays. A similar system based on commercial projectors is used on RICH 2. The calibration is performed in dedicated runs with dipole field on and off. The calibration parameters are then stored in the Conditions Database and applied to the LHC collision data reconstruction. This report will present the improvement in Cherenkov angular resolutions with the magnetic calibration. [Copyright &y& Elsevier]

Abstract: In addition to the narrow spin-one resonances , and occurring in low-scale technicolor, there will be relatively narrow scalars in the mass range 200 to 600–700 GeV. We study the lightest isoscalar state, . In several important respects it is like a heavy Higgs boson with a small vev. It may be discoverable with high luminosity at the LHC where it is produced via weak boson fusion and likely has substantial and decay modes. [Copyright &y& Elsevier]

Abstract: In the framework of the left–right twin Higgs (LRTH) model, we study the production of a pair of SM-like Higgs bosons at the LHC (Higgs mass is typical in the range of 160–180 GeV). First, we examine the production rate and find that it can be significantly larger than the SM prediction. Then we investigate the decays of the Higgs-pair and find that in some parameter space the new decay mode ( is a candidate for WIMP dark matter) can be important, which can suppress sizably the conventional decay modes like , and . Finally, we study the promising channel and find that the rate can be sizably enhanced or suppressed compared with the SM prediction. [ABSTRACT FROM AUTHOR]

Abstract: LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is the silicon detector surrounding the interaction point and will be located only 7mm from the LHC beam during normal operation. The beauty and charm hadrons are identified through their flight distance in the VELO, and hence the detector is critical for both the trigger and offline physics analyses. The VELO has been commissioned and successfully operated during the initial running period of the LHC. The detector has been time aligned to the LHC beam, and spatially aligned. Preliminary operational results show a signal to noise ratio of 20:1, a cluster finding efficiency of 99.6%, and a best single hit precision of . [ABSTRACT FROM AUTHOR]