A fast MPP algorithm for Ising spin exchange simulations

A very efficient massively parallel processor (MPP) algorithm is described for performing one important class of Ising spin simulations. Results and physical significance of MPP calculations using the method described is discussed elsewhere. A few comments, however, are made on the problem under study and results so far are reported. Ted Einstein provided guidance in interpreting the initial results and in suggesting calculations to perform

Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project

The LHCb experiment is preparing for a major upgrade in 2018-2019. One of the key components in the upgrade is a new silicon tracker situated upstream of the analysis magnet of the experiment. The Upstream Tracker (UT) will consist of four planes of silicon strip detectors, with each plane covering an area of about 2 m$^2$. An important consideration of these detectors is their performance after they have been exposed to a large radiation dose. In this article we present test beam results of pre-prototype n-in-p and p-in-n sensors that have been irradiated with fluences up to $4.0\times10^{14}$ $n_{\rm eq}$ cm$^{-2}$.Comment: 25 pages, 20 figure

Branching Fractions for chi_cJ -\u3e p p-bar pi^0, p p-bar eta, and p p-bar omega

Using a sample of 25.9 million psi(2S) decays acquired with the CLEO-c detector at the CESR e^+e^- collider, we report branching fractions for the decays chi_cJ -\u3e p p-bar pi^0, p p-bar eta, and p p-bar omega, with J=0,1,2. Our results for B(chi_cJ-\u3e p p-bar pi^0) and B(chi_cJ-\u3e p p-bar eta) are consistent with, but more precise than, previous measurements. Furthermore, we include the first measurement of B(chi_cJ-\u3e p p-bar omega)

Observation of the Dalitz Decay Ds*+ → Ds*+ e+e-

Using 586 \textrm{pb}^{-1} of e^{+}e^{-} collision data acquired at \sqrt{s}=4.170 GeV with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-} with a significance of 5.3 \sigma. The ratio of branching fractions \calB(D_{s}^{*+} \to D_{s}^{+} e^{+} e^{-}) / \calB(D_{s}^{*+} \to D_{s}^{+} \gamma) is measured to be [ 0.72^{+0.15}_{-0.13} (\textrm{stat}) \pm 0.10 (\textrm{syst})]%, which is consistent with theoretical expectations

Determination of f_s/f_d for 7 TeV pp Collisions and a Measurement of the Branching Fraction of the Decay Bd-\u3eD-K+

The relative abundance of the three decay modes B_d \to D^- K^+, B_d \to D^- \pi^+ and B_s \to D_s^- \pi^+ produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb^{-1}. The branching fraction of B_d \to D^- K^+ is found to be \cal B (B_d \to D^- K^+) = (2.01 \pm 0.18^{\textrm{stat}} \pm 0.14^{\textrm{syst}})\times 10^{-4}. The ratio of fragmentation fractions \fsfdt is determined through the relative abundance of B_s \to D_s^- \pi^+ to B_d \to D^- K^+ and B_d \to D^-\pi^+, leading to f_s/f_d = 0.253 \pm 0.017 \pm 0.017 \pm 0.020, where the uncertainties are statistical, systematic, and theoretical respectively

Study of Ψ(2S) Decays to γpp, π0pp and η pp and Search for pp Threshold Enhancements

The decays of psi(2S) into gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been studied with the CLEO-c detector using a sample of 24.5 million psi(2S) events obtained from e^+e^- annihilations at sqrt{s} = 3686 MeV. The data show evidence for the excitation of several N^* resonances in p pi^0 and p eta channels in pi^0 p bar{p} and eta p bar{p} decays, and f_2 states in gamma p bar{p} decay. Branching fractions for decays of psi(2S) to gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been determined. No evidence for p bar{p} threshold enhancements was found in the reactions psi(2S)-\u3e X p bar{p}, where X = gamma, pi^0, eta. We do, however, find confirming evidence for a p bar{p} threshold enhancement in J/psi-\u3e gamma p bar{p} as previously reported by BES

Observation of the Hc(1P) Using e+e- Collisions Above DD Threshold

Using 586pb^-1 of e^+e^- collision data at E_CM = 4170MeV, produced at the CESR collider and collected with the CLEO-c detector, we observe the process e^+e^- --\u3e pi^+ pi^- h_c(1P). We measure its cross section to be 15.6+-2.3+-1.9+-3.0pb, where the third error is due to the external uncertainty on the branching fraction of psi(2S) --\u3e pi^0 h_c(1P), which we use for normalization. We also find evidence for e^+e^- --\u3e eta h_c(1P) at 4170MeV at the 3sigma level, and see hints of a rise in the e^+e^- --\u3e pi^+ pi^- h_c(1P) cross section at 4260MeV

Prompt K0S Production in pp Collisions at √s=0.9 TeV

The production of K_short 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 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 \u3c pT \u3c 1.6 GeV/c and 2.5 \u3c y \u3c 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations

Analysis of D+ → K-π+ e+ νe and D+ → K- π+ μ+ νμ Semileptonic Decays

Using a large sample (~11800 events) of D^+ into K^- pi^+ e^+ nu_e and D^+ into K^- pi^+ mu^+ nu_mu decays collected by the CLEO-c detector running at the psi(3770), we measure the helicity basis form factors free from the assumptions of spectroscopic pole dominance and provide new, accurate measurements of the absolute branching fractions for D^+ into K^- pi^+ e^+ nu_e and D^+ into K^- pi^+ mu^+ nu_mu decays. We find branching fractions which are consistent with previous world averages. Our measured helicity basis form factors are consistent with the spectroscopic pole dominance predictions for the three main helicity basis form factors describing D^+ into anti-K*0 ell^+ nu_mu decay. The ability to analyze D^+ into K^- pi^+ mu^+ nu_mu allows us to make the first non-parametric measurements of the mass-suppressed form factor. Our result is inconsistent with existing Lattice QCD calculations. Finally, we measure the form factor that controls non-resonant s-wave interference with the D^+ into anti-K*0 ell^+ nu_mu amplitude and search for evidence of possible additional non-resonant d-wave or f-wave interference with the anti-K*0