Upper limit on the prompt muon flux derived from the LVD data

title: Progress report from the UK Dark Matter search at Boulby Mine
abstract: The UK Dark Matter Collaboration is currently running a series of scintillation devices at the Boulby mine in North Yorkshire to search for the neutralino, the hypothetical WIMP solution to the dark matter problem. Results of the current NaI(T1) detector array will be discussed, illustrating a population of events of unknown origin. Diagnostic tests performed to investigate the origin of these anomalous events will be outlined, including alpha, beta and neutron calibrations.

title: Muon-induced background in the EDELWEISS dark matter search
abstract: A dedicated analysis of the muon-induced background in the EDELWEISS dark matter search has been performed on a data set acquired in 2009 and 2010. The total muon flux underground in the Laboratoire Souterrain de Modane (LSM) was measured to be Φ μ = ( 5.4 ± 0.2 - 0.9 + 0.5 )  muons/m 2 /d. The modular design of the μ -veto system allows the reconstruction of the muon trajectory and hence the determination of the angular dependent muon flux in LSM. The results are in good agreement with both MC simulations and earlier measurements. Synchronization of the μ -veto system with the phonon and ionization signals of the Ge detector array allowed identification of muon-induced events. Rates for all muon-induced events Γ μ = ( 0.172 ± 0.012 ) evts / ( kg d ) and of WIMP-like events Γ μ – n = 0.008 - 0.004 + 0.005 evts / ( kg d ) were extracted. After vetoing, the remaining rate of accepted muon-induced neutrons in the EDELWEISS-II dark matter search was determined to be Γ irred μ – n 6 · 10 - 4 evts / ( kg d ) at 90% C.L. Based on these results, the muon-induced background expectation for an anticipated exposure of 3000 kg d for EDELWEISS-III is N 3000 kg d μ – n 0.6 events.

title: The ZEPLIN-III dark matter detector: Performance study using an end-to-end simulation tool
abstract: We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon by interacting particles and radiation. The software models the instrument response to radioactive backgrounds and calibration sources, including the generation, ray-tracing and detection of the primary and secondary scintillations in liquid and gaseous xenon, and subsequent processing by data acquisition electronics. A flexible user interface allows easy modification of detector parameters at run time. Realistic datasets can be produced to help with data analysis, an example of which is the position reconstruction algorithm developed from simulated data. We present a range of simulation results confirming the original design sensitivity of a few times 10−8 pb to the WIMP-nucleon cross-section.

title: Particle polarization in inclusive reactions

title: The potential of liquid xenon for WIMP search: the ZEPLIN diagnostic array
abstract: A Liquid Xenon based WIMP detector diagnostic array is currently developed by the UKDMC with the help of international collaborators. After a brief reminder on the detection principle in Liquid Xenon, the individual detectors will be described. ZEPLIN I, a detector with a 4 kg fiducial mass with a background discrimination based on Pulse Shape Analysis, is already underground and starting operation. Two setups with improved background discrimination tools (as the ionisation is also recorded) are designed and scheduled to move underground in the second half of 2001. Both of them, ZEPLIN II and ZEPLIN III, are predicted to be sensitive to rate of 0.1–0.01 events/kg/day within 2 years of data taking. Furthermore, new ideas for lower background readout devices are studied, in order to avoid the use of PhotoMultiplier Tubes (PMTs).

title: Search for the rare decay $D^0 \to \mu^+ \mu^-$
abstract: A search for the rare decay $D^0 \to \mu^+ \mu^-$is performed using a data sample, corresponding to an integrated luminosity of 0.9 fb$^{-1}$, of $pp$ collisions collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The observed number of events is consistent with the background expectations and corresponds to an upper limit of \mbox{${\cal B}(D^0 \to \mu^+ \mu^-) < 6.2(7.6) \times 10^{-9}$} at \mbox{90%} \mbox{(95%)} confidence level. This result represents an improvement of more than a factor twenty with respect to previous measurements.

title: Measurement of the resonant and CP components in $\overline{B}^0\to J/\psi \pi^+\pi^-$ decays
abstract: The resonant structure of the reaction $\overline{B}^0\rightarrow J/\psi \pi^+\pi^-$ is studied using data from 3 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment, one-third at 7 Tev center-of-mass energy and the remainder at 8 Tev. The invariant mass of the $\pi^+\pi^-$ pair and three decay angular distributions are used to determine the fractions of the resonant and non-resonant components. Six interfering $\pi^+\pi^-$ states: $\rho(770)$, $f_0(500)$, $f_2(1270)$, $\rho(1450)$, $\omega(782)$ and $\rho(1700)$ are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative CP fractions of each of the resonant final states are determined. The $f_0(980)$ meson is not seen and the upper limit on its presence, compared with the observed $f_0(500)$ rate, is inconsistent with a model of tetraquark substructure for these scalar mesons at the eight standard deviation level. In the $q\overline{q}$ model, the absolute value of the mixing angle between the $f_0(980)$ and the $f_0(500)$ scalar mesons is limited to be less than $17^{\circ}$ at 90% confidence level.

title: Composite superstring model for hadron amplitudes
abstract: Hadron dynamics is formulated in terms of interacting composite strings. These composite string amplitudes give other possible solution of duality equations for crossing channels in addition to classical string amplitudes. The composite strings carry quark flavour and spin degrees of freedom on edging two-dimensional surfaces. Consistent composite string models with extended N = 3 Virasoro superconformal symmetry are found. Simple amplitudes for interaction of π and K-mesons in this model are represented.

title: Test of lepton universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ decays
abstract: A measurement of the ratio of the branching fractions of the $B^{+}\rightarrow K^{+}\mu^{+}\mu^{-}$ and $B^{+}\rightarrow K^{+}e^{+}e^{-}$ decays is presented using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, recorded with the LHCb experiment at center-of-mass energies of 7 and 8 $\mathrm{\,Te\kern -0.1em V}$. The value of the ratio of branching fractions for the dilepton invariant mass squared range $1<q^{2}<6\mathrm{\,Ge\kern -0.1em V^2\!/}c^4$ is measured to be $0.745^{+0.090}_{-0.074}\mathrm{\,(stat)}\,\pm0.036\mathrm{\,(syst)}$. This value is the most precise measurement of the ratio of branching fractions to date and is compatible with the SM prediction within $2.6$ standard deviations.

title: Search for the lepton-flavor violating decays $B^0_s \rightarrow e^{\pm}\mu^{\mp}$ and $B^0 \rightarrow e^{\pm} \mu^{\mp}$
abstract: A search for the lepton-flavour violating decays $B^0_s \to e^{\pm} \mu^{\mp}$ and $B^0 \to e^{\pm} \mu^{\mp}$ is performed with a data sample, corresponding to an integrated luminosity of 1.0 fb$^{-1}$ of $pp$ collisions at $\sqrt{s} = 7$ TeV, collected by the LHCb experiment. The observed number of $B^0_s \to e^{\pm} \mu^{\mp}$ and $B^0 \to e^{\pm} \mu^{\mp}$ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be $BR(B^0_s \to e^{\pm} \mu^{\mp}) 107$ TeV/c$^2$ and $M_{\rm LQ} (B^0 \to e^{\pm} \mu^{\mp}) > 126$ TeV/c$^2$ at 95% C.L., and are a factor of two higher than the previous bounds.