We study the process $e^+e^-\to\psi(2S)\pi^{+}\pi^{-}$ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the \BaBar detector at ...center-of-mass energies at and near the $\Upsilon(\mathrm{nS})$ (n = 2, 3, 4) resonances and correspond to an integrated luminosity of 520$fb^{-}$. We investigate the $\psi(2S)\pi^{+}\pi^{-}$ mass distribution from 3.95 to 5.95 $GeV/c^{2}$, and measure the center-of-mass energy dependence of the associated $e^+e^-\to \psi(2S)\pi^{+}\pi^{-}$ cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the $\psi(2S)\pi^{+}\pi^{-}$ mass distribution corresponding to the decay mode $\psi(2S)\to J/\psi \pi^{+}\pi^{-}$ yields a mass value of $4340 \pm16$ (stat) $\pm 9$ (syst) ${\mathrm {MeV/c^{2}}}and a width of $94 \pm 32$ (stat) $\pm 13$ (syst) MeV for the first resonance, and for the second a mass value of $4669 \pm 21$ (stat) $\pm 3$ (syst) ${\mathrm {MeV/c^{2}}}$ and a width of $104 \pm 48$ (stat) $\pm 10$ (syst) MeV. In addition, we show the $pi^{+}\pi^{-}$ mass distributions for these resonant regions.
Early in the operation of the SLD CCD vertex detector (VXD3) at the SLC, radiation damage to the CCDs was observed. It is well known that low-energy light particles (electrons and photons) are a few ...orders of magnitude less effective than heavy particles (neutrons or heavy charged particles) in the generation of radiation damage effects in silicon. The SLD environment was known to be dominated by electrons and photons with a small fraction of neutrons. The estimated radiation damage by these particles cannot account for the observed damage. Therefore, this damage is puzzling. A CCD-based detector is a leading option for vertex detection at the future linear collider (LC). A full understanding of background models in LCs and the associated damage is needed. Earlier results on neutron damage to an SLD CCD were reported at the 1999 IEEE NSS, and these new results complement our old results. In addition to tests on controlled exposures of individual CCDs, we have studied the nature of the traps produced in the SLD vertex detector to assess their origin-whether heavy or light particles.
A new hardware trigger system based on tracks detected by a stereo drift chamber has been developed for the BABAR experiment at the Stanford Linear Accelerator Center. The z/sub 0/p/sub T/ ...Discriminator (ZPD) is capable of fast, three-dimensional reconstruction of charged particle tracks and provides rejection of background events due to beam particles interacting with the beam pipe at the first-level trigger. Over 1 gigabyte of data is processed per second by each ZPD module. Rapid track reconstruction has been realized using Xilinx Virtex-II FPGAs.
Abstract
We find that it is possible to increase sensitivity to low energy physics in a third or fourth Deep Underground Neutrino Experiment (DUNE)-like module with careful controls over radiopurity ...and targeted modifications to a detector similar to the DUNE Far Detector design. In particular, sensitivity to supernova and solar neutrinos can be enhanced with improved MeV-scale reach. A neutrinoless double beta decay search with
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Xe loading appears feasible. Furthermore, sensitivity to Weakly-Interacting Massive Particle (WIMP) Dark Matter becomes competitive with the planned world program in such a detector, offering a unique seasonal variation detection that is characteristic of the nature of WIMPs.
The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This ...mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ̃ confidence level, using a low-background, 14.6-kilogram CsINa scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.
We present final measurements of the Z boson-lepton coupling asymmetry parameters A(e), A(mu), and A(tau) with the complete sample of polarized Z bosons collected by the SLD detector at the SLAC ...Linear Collider. From the left-right production and decay polar angle asymmetries in leptonic Z decays we measure A(e) = 0.1544+/-0.0060, A(mu) = 0.142+/-0.015, and A(tau) = 0.136+/-0.015. Combined with our left-right asymmetry measured from hadronic decays, we find A(e) = 0.1516+/-0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin (2)theta(eff)(W) = 0.230 98+/-0.000 26.
We present a measurement of the left-right cross-section asymmetry ( A(LR)) for Z boson production by e(+)e(-) collisions. The measurement includes the final data taken with the SLD detector at the ...SLAC Linear Collider during the period 1996-1998. Using a sample of 383 487 Z decays collected during the 1996-1998 runs we measure the pole value of the asymmetry, A(0)(LR), to be 0.150 56+/-0.002 39 which is equivalent to an effective weak mixing angle of sin (2)straight theta(eff)(W) = 0.231 07+/-0.000 30. Our result for the complete 1992-1998 data set comprising approximately 537 000 Z decays is sin (2)straight theta(eff)(W) = 0.230 97+/-0.000 27.
We have studied a CCD vertex detector design for a future linear collider and report methods under consideration for radiation damage remediation in the linear collider environment. Noting the rich ...physics program available with a precise vertex detector, we report the expected precision on the Standard Model Higgs boson branching ratios with the described design and the efforts towards improving the topological vertex reconstruction algorithms.
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