V. E. Blinov

Status of the KEDR detector

Abstract KEDR is a general-purpose detector for experiments at the VEPP-4M e + e − -collider in the energy range 2 E =2.0– 12 GeV . All detector subsystems (except the aerogel Cherenkov counters) have been installed into the detector at VEPP-4M. Some preliminary data have been taken in the energy region of the J/Ψ meson. The tuning of the detector and the VEPP-4M collider is in progress. Preliminary results on the detector performance are presented. The future experimental program for the KEDR detector is discussed.

Measurement of the τ lepton mass at the KEDR detector

A precise τ lepton mass measurement performed at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ+τ− cross section behavior around the production threshold. The result based on 6.7 pb−1 of data is mτ = 1776.81−0.23+0.25 ± 0.15 MeV. Using 0.8 pb−1 of data collected at the ψ′ peak, we have also determined that ΓeeBττ(ψ′) = 9.0 ± 2.6 eV.

Measurements of moments of the hadronic mass distribution in semileptonic B decays

B. Aubert, R. Barate, D. Boutigny, F. Couderc, J.-M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, V. Tisserand, A. Zghiche, A. Palano, A. Pompili, J. C. Chen, N. D. Qi, G. Rong, P. Wang, Y. S. Zhu, G. Eigen, I. Ofte, B. Stugu, G. S. Abrams, A. W. Borgland, A. B. Breon, D. N. Brown, J. Button-Shafer, R. N. Cahn, E. Charles, C. T. Day, M. S. Gill, A. V. Gritsan, Y. Groysman, R. G. Jacobsen, R. W. Kadel, J. Kadyk, L. T. Kerth, Yu. G. Kolomensky, G. Kukartsev, C. LeClerc, M. E. Levi, G. Lynch, L. M. Mir, P. J. Oddone, T. J. Orimoto, M. Pripstein, N. A. Roe, M. T. Ronan, V. G. Shelkov, A. V. Telnov, W. A. Wenzel, K. Ford, T. J. Harrison, C. M. Hawkes, S. E. Morgan, A. T. Watson, N. K. Watson, M. Fritsch, K. Goetzen, T. Held, H. Koch, B. Lewandowski, M. Pelizaeus, K. Peters, H. Schmuecker, M. Steinke, J. T. Boyd, N. Chevalier, W. N. Cottingham, M. P. Kelly, T. E. Latham, C. Mackay, F. F. Wilson, K. Abe, T. Cuhadar-Donszelmann, C. Hearty, T. S. Mattison, J. A. McKenna, D. Thiessen, P. Kyberd, A. K. McKemey, L. Teodorescu, V. E. Blinov, A. D. Bukin, V. B. Golubev, V. N. Ivanchenko, E. A. Kravchenko, A. P. Onuchin, S. I. Serednyakov, Yu. I. Skovpen, E. P. Solodov, A. N. Yushkov, D. Best, M. Bruinsma, M. Chao, I. Eschrich, D. Kirkby, A. J. Lankford, M. Mandelkern, R. K. Mommsen, W. Roethel, D. P. Stoker, C. Buchanan, B. L. Hartfiel, J. W. Gary, J. Layter, B. C. Shen, K. Wang, D. del Re, H. K. Hadavand, E. J. Hill, D. B. MacFarlane, H. P. Paar, Sh. Rahatlou, V. Sharma, J. W. Berryhill, C. Campagnari, B. Dahmes, S. L. Levy, O. Long, A. Lu, M. A. Mazur, J. D. Richman, W. Verkerke, T. W. Beck, J. Beringer, A. M. Eisner, C. A. Heusch, W. S. Lockman, T. Schalk, R. E. Schmitz, B. A. Schumm, A. Seiden, P. Spradlin, W. Walkowiak, D. C. Williams, M. G. Wilson, J. Albert, E. Chen, G. P. Dubois-Felsmann, A. Dvoretskii, R. J. Erwin, D. G. Hitlin, I. Narsky, T. Piatenko, F. C. Porter, A. Ryd, A. Samuel, S. Yang, S. Jayatilleke, G. Mancinelli, B. T. Meadows, M. D. Sokoloff, T. Abe, F. Blanc, P. Bloom, S. Chen, P. J. Clark, W. T. Ford, U. Nauenberg, A. Olivas, P. Rankin, J. Roy, J. G. Smith, W. C. van Hoek, L. Zhang, J. L. Harton, T. Hu, A. Soffer, W. H. Toki, R. J. Wilson, J. Zhang, D. Altenburg, T. Brandt, J. Brose, T. Colberg, M. Dickopp, E. Feltresi, A. Hauke, H. M. Lacker, E. Maly, R. Müller-Pfefferkorn, R. Nogowski, S. Otto, J. Schubert, K. R. Schubert, R. Schwierz, B. Spaan, D. Bernard, G. R. Bonneaud, F. Brochard, P. Grenier, Ch. Thiebaux, G. Vasileiadis, M. Verderi, D. J. Bard, A. Khan, D. Lavin, F. Muheim, S. Playfer, M. Andreotti, V. Azzolini, D. Bettoni, C. Bozzi, R. Calabrese, G. Cibinetto, E. Luppi, M. Negrini, L. Piemontese, A. Sarti, E. Treadwell, R. Baldini-Ferroli, A. Calcaterra, R. de Sangro, G. Finocchiaro, P. Patteri, M. Piccolo, A. Zallo, A. Buzzo, R. Capra, R. Contri, G. Crosetti, M. Lo Vetere, M. Macri, M. R. Monge, S. Passaggio, C. Patrignani, E. Robutti, A. Santroni, S. Tosi, S. Bailey, M. Morii, E. Won, R. S. Dubitzky, U. Langenegger, W. Bhimji, D. A. Bowerman, P. D. Dauncey, U. Egede, J. R. Gaillard, G. W. Morton, J. A. Nash, G. P. Taylor, G. J. Grenier, S.-J. Lee, U. Mallik, J. Cochran, H. B. Crawley, J. Lamsa, W. T. Meyer, S. Prell, E. I. Rosenberg, J. Yi, M. Davier, G. Grosdidier, A. Höcker, S. Laplace, F. Le Diberder, V. Lepeltier, A. M. Lutz, T. C. Petersen, S. Plaszczynski, M. H. Schune, L. Tantot, G. Wormser, V. Brigljević, C. H. Cheng, D. J. Lange, M. C. Simani, D. M. Wright, A. J. Bevan, J. P. Coleman, J. R. Fry, E. Gabathuler, R. Gamet, M. Kay, R. J. Parry, D. J. Payne, R. J. Sloane, C. Touramanis, J. J. Back, P. F. Harrison, G. B. Mohanty, C. L. Brown, G. Cowan, R. L. Flack, H. U. Flaecher, S. George, M. G. Green, A. Kurup, C. E. Marker, T. R. McMahon, S. Ricciardi, F. Salvatore, G. Vaitsas, M. A. Winter, D. Brown, C. L. Davis, J. Allison, N. R. Barlow, R. J. Barlow, P. A. Hart, M. C. Hodgkinson, G. D. Lafferty, A. J. Lyon, J. C. Williams, A. Farbin, W. D. Hulsbergen, A. Jawahery, D. Kovalskyi, C. K. Lae, V. Lillard, D. A. Roberts, G. Blaylock, C. Dallapiccola, K. T. Flood, S. S. Hertzbach, R. Kofler, V. B. Koptchev, T. B. Moore, S. Saremi, H. Staengle, S. Willocq, R. Cowan, G. Sciolla, F. Taylor, R. K. Yamamoto, D. J. J. Mangeol,

Measurement of Γee(J/ψ)⋅B(J/ψ→e+e−) and Γee(J/ψ)⋅B(J/ψ→μ+μ−)

The products of the electron width of the J/ψJ/ψ meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron–positron collider. The results are Γee×Γee/Γ=0.3323±0.0064(stat.)±0.0048(syst.) keV,Γee×Γee/Γ=0.3323±0.0064(stat.)±0.0048(syst.) keV, Γee×Γμμ/Γ=0.3318±0.0052(stat.)±0.0063(syst.) keV.Γee×Γμμ/Γ=0.3318±0.0052(stat.)±0.0063(syst.) keV. Their combinations Γee×(Γee+Γμμ)/Γ=0.6641±0.0082(stat.)±0.0100(syst.) keV,Γee×(Γee+Γμμ)/Γ=0.6641±0.0082(stat.)±0.0100(syst.) keV, Γee/Γμμ=1.002±0.021(stat.)±0.013(syst.)Γee/Γμμ=1.002±0.021(stat.)±0.013(syst.) can be used to improve the accuracy of the leptonic and full widths and test leptonic universality. Assuming eμ universality and using the world average value of the lepton branching fraction, we also determine the leptonic Γll=5.59±0.12 keVΓll=5.59±0.12 keV and total Γ=94.1±2.7 keVΓ=94.1±2.7 keV widths of the J/ψJ/ψ meson.The products of the electron width of the J/\psi meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations \Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100) keV, \Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming e\mu universality and using the world average value of the lepton branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.

Measurement of D0 and D + meson masses with the KEDR Detector

Abstract The masses of the neutral and charged D mesons have been measured with the KEDR detector at the VEPP-4M electron–positron collider: M D 0 = 1865.30 ± 0.33 ± 0.23 MeV , M D + = 1869.53 ± 0.49 ± 0.20 MeV .

Analysis of errors and estimation of accuracy in the experiment on precise mass measurement of J/ψ, ψ' mesons and τ-lepton on the VEPP-4M collider

Abstract The goal of this work is an evaluation of utmost precision and analysis of any possible errors and corrections in planned experiment of new mass measurement of J/ψ and ψ′ mesons on VEPP-4M collider with absolute energy calibration by the spin precession frequency measurements.

High precision mass measurements in Ψ and ϒ families revisited

Abstract High precision mass measurements in Ψ and ϒ families performed in 1980–1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J / Ψ (1 S ) and Ψ (2 S ) mass measurements.

The KEDR drift chamber

Abstract The design features of the KEDR drift chamber are described. The 1 m long and 1 m outer diameter cylindrical chamber consists of seven radial super layers. The multiwire drift cell contains six sense wires with a distance of 4.5 mm. The maximum drift distance is 30 mm. Measurements of spatial resolution and aging tests were performed using DME gas with a prototype. The resolution averaged over drift distance has a value of 40 μm. The relative gain drop is equal to 45%/(C/cm). This would correspond to 2% pulse height decrease per year at a gas gain of 105 and flux of the charged particles of 1 kHz/cm2.

Recent results from the KEDR detector

We report results of experiments performed with the KEDR detector at the VEPP-4M e+e− collider. They include precise measurement of the D0 and D± meson masses, determination of the ψ(3770) resonance parameters, and a search for narrow resonances in e+e− annihilation at center-of-mass energies between 1.85 and 3.1 GeV.

Aging in wire chamber filled with dimethyl ether

The different methods for the measurement of wire chamber aging were analyzed and a more correct procedure was proposed. A study of aging effects under intense radiation in drift chambers filled with dimethyl ether (DME), argon/carbon dioxide and argon/isobutane was performed. The influence of the materials and gain on the aging rate with DME was investigated. With a drift tube in clean conditions the relative gain drop R of 1.7%/(C/cm) was measured. For the drift chamber of the KEDR detector R is 45%/(C/cm). This corresponds to a 2% pulse height decrease per year at a gain of 105 and flux of the charged particles of 1 kHz/cm2. We conclude that, providing careful choice of the wire chamber and tubing materials, the DME filled drift chamber can be run without considerable aging effects.