67788877
First Data from DM-Ice17
Astrophysical observations have provided convincing evidence for the existence of dark matter, yet direct observation of the dark matter particles has not been conclusively established. DAMA experiment claimed to have observed the annual modulation signal of dark matter using NaI detectors at the Gran Sasso Lab in Italy. The DM-Ice project aims to conclusively test this claim with a new detector array at the South Pole. It will be one of the first direct dark matter detection experiments in the southern hemisphere. DM-Ice17 is a prototype 17 kg NaI detector deployed in the South Pole ice. The speaker will report first data collected with the detector and discuss R&D progress and prospects of the full scale DM-Ice detector.
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.
115887438
Particle polarization in inclusive reactions
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).
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.
208248288
Search for the doubly charmed baryon $$\Xi_{cc}^+$$
A search for the doubly charmed baryon \(\Xi_{cc}^+\) is performed through its decay to the \(\Lambda_c^ + {K^ -}{\pi ^ +}\) final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data correspond to a total integrated luminosity of 9 fb−1. No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c2. Upper limits are set at 95% credibility level on the ratio of the \(\Xi_{cc}^+\) production cross-section times the branching fraction to that of \(\Lambda_c^ + \) and \(\Xi_{cc}^{+ +}\) baryons. The limits are determined as functions of the \(\Xi_{cc}^+\) mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.
15571332
Spinor representations of the Virasoro and super-Virasoro algebras for conformal spin to be equal 1
It is considered here the possibility of unitary spinor representations of the Virasoro and super-Virasoro algebras for conformal spin to be equal 1 ; k are integers.
119194940
Measurement of b-hadron branching fractions for two-body decays into charmless charged hadrons
A bstractBased on data corresponding to an integrated luminosity of 0.37 fb−1 collected by the LHCb experiment in 2011, the following ratios of branching fractions are measured:$ \begin{array}{*{20}{c}} {{{{\mathcal{B}\left( {B^0 \to {\pi^{+}}{\pi^{-}}} \right)}} \left/ {{\mathcal{B}\left( {B^0 \to {K^{+}}{\pi^{-}}} \right)}} \right.}=0.262\pm 0.009\pm 0.017,} \\ {\left( {{f_s \left/ {f_d } \right.}} \right)\cdot {{{\mathcal{B}\left( {B_s^0\to {K^{+}}{K^{-}}} \right)}} \left/ {{\mathcal{B}\left( {B^0 \to {K^{+}}{\pi^{-}}} \right)}} \right.}=0.316\pm 0.009\pm 0.019,} \\ {\left( {{f_s \left/ {f_d } \right.}} \right)\cdot {{{\mathcal{B}\left( {B_s^0\to {\pi^{+}}{K^{-}}} \right)}} \left/ {{\mathcal{B}\left( {B^0 \to {K^{+}}{\pi^{-}}} \right)}} \right.}=0.074\pm 0.006\pm 0.006,} \\ {\left( {{f_d \left/ {f_s } \right.}} \right)\cdot {{{\mathcal{B}\left( {B^0 \to {K^{+}}{K^{-}}} \right)}} \left/ {{\mathcal{B}\left( {B_s^0\to {K^{+}}{K^{-}}} \right)}} \right.}=0.018_{-0.007}^{+0.008}\pm 0.009,} \\ {\left( {{f_s \left/ {f_d } \right.}} \right)\cdot {{{\mathcal{B}\left( {B_s^0\to {\pi^{+}}{\pi^{-}}} \right)}} \left/ {{\mathcal{B}\left( {B^0 \to {\pi^{+}}{\pi^{-}}} \right)}} \right.}=0.050_{-0.009}^{+0.011}\pm 0.004,} \\ {{{{\mathcal{B}\left( {\Lambda_b^0\to p{\pi^{-}}} \right)}} \left/ {{\mathcal{B}\left( {\Lambda_b^0\to p{K^{-}}} \right)}} \right.}=0.86\pm 0.08\pm 0.05,} \\ \end{array} $where the first uncertainties are statistical and the second systematic. Using the current world average of $ \mathcal{B}\left( {B^0 \to {K^{+}}{\pi^{-}}} \right) $ and the ratio of the strange to light neutral B meson production fs/fd measured by LHCb, we obtain:$ \begin{array}{*{20}{c}} {\mathcal{B}\left( {B^0 \to {\pi^{+}}{\pi^{-}}} \right)=\left( {5.08\pm 0.17\pm 0.37} \right)\times {10^{-6 }},} \\ {\mathcal{B}\left( {B_s^0\to {K^{+}}{K^{-}}} \right)=\left( {23.0\pm 0.7\pm 2.3} \right)\times {10^{-6 }},} \\ {\mathcal{B}\left( {B_s^0\to {\pi^{+}}{K^{-}}} \right)=\left( {5.4\pm 0.4\pm 0.6} \right)\times {10^{-6 }},} \\ {\mathcal{B}\left( {B^0 \to {K^{+}}{K^{-}}} \right)=\left( {0.11_{-0.04}^{+0.05}\pm 0.06} \right)\times {10^{-6 }},} \\ {\mathcal{B}\left( {B_s^0\to {\pi^{+}}{\pi^{-}}} \right)=\left( {0.95_{-0.17}^{+0.21}\pm 0.13} \right)\times {10^{-6 }}.} \\ \end{array} $
 The measurements of $ \mathcal{B}\left( {B_s^0\to {K^{+}}{K^{-}}} \right) $, $ \mathcal{B}\left( {B_s^0\to {\pi^{+}}{K^{-}}} \right) $ and $ \mathcal{B}\left( {B^0 \to {K^{+}}{K^{-}}} \right) $ are the most precise to date. The decay mode $ B_s^0\to {\pi^{+}}{\pi^{-}} $ is observed for the first time with a significance of more than 5σ.
116007687
Observation of the decay $B_c \rightarrow J/\psi K^+ K^- \pi^+ $
The decay $B_c\rightarrow J/\psi K^+ K^- \pi^+$ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of $78\pm14$ decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of $\B_c \rightarrow J/\psi K^+ K^- \pi^+$ decays to that of $B_c \rightarrow J/\psi \pi^+$ decays is measured to be $0.53\pm 0.10\pm0.05$, where the first uncertainty is statistical and the second is systematic.
115637888
Are there any sister trajectories in the Veneziano model
The question of the existence of ''sister'' Regge trajectories in the Veneziano dual model is discussed. It is shown that the arguments of Hoyer, Toernqvist, and Webber, favoring the contribution of a ''sister'' trajectory with half the slope of the ordinary Regge trajectory to the asymptotic 6-particle Veneziano amplitude, are unfounded.