This review discusses the application of aerogel Cherenkov detectors in colliding beam experiments. Such detectors are used for charged particle identification at velocities at which other methods ...are ineffective. The paper examines aerogel production technology and how the aerogel optical parameters are measured. Data on threshold Cherenkov counters with direct light collection and on those using wavelength shifters are evaluated. Also presented are data on Ring Image Cherenkov detectors with single and multilayer focusing aerogel radiators.
Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs ...boson using 516 fb(-1) of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the standard model-dark-sector mixing angle and the dark-sector coupling constant.
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.
The cross sections , , , , K+K−, , , have been measured with the spherical neutral detector at the VEPP-2000 e+e− collider in the energy range from 0.3 to 2.0 GeV.
Study of H-8500 MaPMT for the FDIRC detector at SuperB Gargano, F.; Arnaud, N.; Barnyakov, A.Yu ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
08/2013, Letnik:
718
Journal Article, Conference Proceeding
Recenzirano
An overview of ongoing studies on the Hamamatsu H-8500 Multi-Anode Photomultiplier (MaPMT) is presented. This device will be used for the FDIRC Particle Identification Detector (PID) of the SuperB ...experiment. The H-8500 MaPMT has been chosen for its excellent single photon timing capabilities and its highly pixilated design. Results on timing studies, gain uniformity, single photoelectron detection efficiency uniformity and cross-talk are presented.
We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle ...using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BBover ¯ pairs recorded by the BABAR detector and (772±11)×10^{6}BBover ¯ pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2β=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=22.5±4.4(stat)±1.2(syst)±0.6(model)°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→ccover ¯ data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2β>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-β=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
The work concerns the development of aerogel radiators for RICH detectors. Aerogel tiles with a refractive index of 1.05 were tested with a RICH prototype on the electron beam on the VEPP-4M ...collider. It has been shown that polishing with silk tissue yields good surface quality, the amount of light loss at this surface being about 5–7%. The Cherenkov angle resolution was measured for a tile in two conditions: with a clean exit face and with a polished exit face. The number of photons detected was 13.3 and 12.7 for the clean and polished surfaces, respectively. The Cherenkov angle resolution for the polished surface is 55% worse, which can be explained with the forward scattering on the polished surface. A tile with a crack inside was also tested. The experimental data show that the Cherenkov angle resolution is the same for tracks crossing the crack area and in a crack-free area.
Focusing Aerogel RICH for particle identification and momentum measurement Barnyakov, A.Yu; Barnyakov, M.Yu; Basok, I.Yu ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2011, Letnik:
639, Številka:
1
Journal Article
Recenzirano
The work is devoted to the development of the Focusing Aerogel RICH (FARICH). The option of the forward RICH for the SuperB project in Italy is presented. It features an aerogel-NaF radiator and MCP ...photodetectors. Monte Carlo simulation predicts the
π
/ K separation at the level better than
3
σ
from 0.2 to 7
GeV/
c, the
μ
/
π
separation—from 0.13 to 1.3
GeV/
c, and the kaon momentum measurement with an accuracy of about 1% at 1
GeV/
c. FARICH for the Super Charm-Tau Factory project in Novosibirsk is proposed. Monte Carlo simulation predicts
μ
/
π
separation at the level better than
3
σ
for a momentum from 0.3 to 1.7
GeV/
c. A prototype will be tested on the new electron test beam facility at VEPP-4M collider.
Extracted electron and gamma beams in BINP Abramov, G N; Ahmetshin, R R; Barnyakov, A Yu ...
Journal of instrumentation,
08/2014, Letnik:
9, Številka:
8
Journal Article
Recenzirano
Facility of the extracted beams of electrons and gammas based on the e super(+)e super(-) VEPP-4M collider is described. This installation is designed to test prototype of detectors for HEP projects. ...Design parameters of the extracted electron beam are the following: intensity is not less than 50 Hz, energy range is from 0.1 GeV to 3.0 GeV and energy resolution is about 2-3%. The gamma energy range is from 0.05 GeV to 4.0 GeV with an accuracy of 0.5% of energy. The designed intensity of the gamma beam is about 1000 Hz.
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