119128907
First Results from the DRIFT-IIa Dark Matter Detector
Data from the DRIFT-IIa directional dark matter experiment are presented, collected during a near continuous 6 month running period. A detailed calibration analysis comparing data from gamma-ray, x-ray and neutron sources to a GEANT4 Monte Carlo simulations reveals an efficiency for detection of neutron induced recoils of 94±2(stat.)±5(sys.)%. Software-based cuts, designed to remove non-nuclear recoil events, are shown to reject 60 Co gamma-rays with a rejection factor of better than 8!10 -6 for all energies above threshold. An unexpected event population has been discovered and is shown here to be due to the alpha-decay of 222 Rn daughter nuclei that have attached to the central cathode. A limit on the flux of neutrons in the Boulby Underground Laboratory is derived from analysis of unshielded and shielded data.
120314532
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.
119286983
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.
12347950
The ZEPLIN-III dark matter detector: Performance study using an end-to-end simulation tool
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.
121667127
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).
115887438
Particle polarization in inclusive reactions
118146782
Amplitude analysis and the branching fraction measurement of $\bar{B}^0_s \to J/\psi K^+K^-$
An amplitude analysis of the final state structure in the Bs0→J/ψK+K- decay mode is performed using 1.0  fb-1 of data collected by the LHCb experiment in 7 TeV center-of-mass energy pp collisions produced by the LHC. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. Resonant structures are observed in the K+K- mass spectrum as well as a significant non-resonant S-wave contribution over the entire K+K- mass range. The largest resonant component is the ϕ(1020), accompanied by f0(980), f2′(1525), and four additional resonances. The overall branching fraction is measured to be B(Bs0→J/ψK+K-)=(7.70±0.08±0.39±0.60)×10-4, where the first uncertainty is statistical, the second systematic, and the third due to the ratio of the number of Bs0 to B- mesons produced. The mass and width of the f2′(1525) are measured to be 1522.2±2.8-2.0+5.3  MeV and 84±6-5+10  MeV, respectively. The final state fractions of the other resonant states are also reported.
116301993
Quasi-stable states in the physical spectrum of the Neveu-Schwarz dual model
A certain class of states, comprising most of the spectrum for large mass M, is distinguished in the spectum of physical states predicted by the Neveu-Schwarz dual model with intercepts ..cap alpha../sub rho/(0) =1 and ..cap alpha../sub ..pi../(0) =1/2. The massive particles with large spins in this class are quasi-stable. Their couplings with all the other states are of order M/sup -1/ in comparison with the ordinary vertices. For the critical dimensions D=10 these states coincide with the zero-norm spurions. For the anomalous dimensions D=9 some of the quasi-stable states become new zero-norm spurion states. (AIP)
118631869
Limits on neutral Higgs boson production in the forward region in pp collisions at $ \sqrt{s}=7 $ TeV
A bstractLimits on the cross-section times branching fraction for neutral Higgs bosons, produced in pp collisions at $ \sqrt{s}=7 $ TeV, and decaying to two tau leptons with pseudorapidities between 2.0 and 4.5, are presented. The result is based on a dataset, corresponding to an integrated luminosity of 1.0 fb−1, collected with the LHCb detector. Candidates are identified by reconstructing final states with two muons, a muon and an electron, a muon and a hadron, or an electron and a hadron. A model independent upper limit at the 95% confidence level is set on a neutral Higgs boson cross-section times branching fraction. It varies from 8.6 pb for a Higgs boson mass of 90 GeV to 0.7 pb for a Higgs boson mass of 250 GeV, and is compared to the Standard Model expectation. An upper limit on tan β in the Minimal Supersymmetric Model is set in the $ m_{{{h^0}}}^{\max } $ scenario. It ranges from 34 for a CP -odd Higgs boson mass of 90 GeV to 70 for a pseudo-scalar Higgs boson mass of 140 GeV.

118521922
Implications of LHCb measurements and future prospects
During 2011 the LHCb experiment at CERN collected 1.0 fb−1 of $\sqrt{s} = 7\mbox{~TeV}$pp collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.
204978414
Evidence for the decay $B_c^+ \rightarrow J/\psi 3\pi^+ 2\pi^-$
Evidence is presented for the decay $B_c+\rightarrow J/\psi 3\pi^+2\pi^-$ using proton-proton collision data, corresponding to an integrated luminosity of 3fb$^{-1}$, collected with the LHCb detector. A signal yield of $32\pm8$ decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the $B_c^+\rightarrow J/\psi 3\pi^+ 2\pi^-$ decay to that of the $B_c^+ \rightarrow J/\psi \pi^+$ decay is measured to be $$ \frac{Br (B_c^+ \rightarrow J/\psi 3\pi^+2\pi^)}{Br (B_c^+ \rightarrow J/\psi \pi^+)} = 1.74\pm0.44\pm0.24, $$ where the first uncertainty is statistical and the second is systematic.