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| MOPLT087 |
Research of Possibility to use Beam Polarization for Absolute Energy Calibration in High-precision Measurement of Tau Lepton Mass at VEPP-4M
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737 |
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- A.V. Bogomyagkov, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.A. Nikitin, I.B. Nikolaev, E.A. Simonov, A.N. Skrinsky
BINP SB RAS, Novosibirsk
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Experiments of 2002-2003 years on measurement of duration of beam polarization existence in VEPP-4M electron-positron storage ring after injection of polarized beams from VEPP-3 booster at energies in the vicinity of tau-lepton production threshold (1777 MeV) are described. Polarized beams in such conditions are planned to use in the experiment at VEPP-4M with KEDR detector on high precision measurement of tau-lepton mass wiyh the help of resonant depolarization technique for absolute calibration of particle energy. It was shown that despite of closeness of the strong depolarizing integer spin resonance (1763 MeV) the polarization lifetime though is limited, but still is sufficient for realization of energy calibration procedure with a high accuracy (10-6).
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| THPLT106 |
Measurement of Beam Polarization in VEPP-3 Storage Ring using Internal Target-based Moeller Polarimeter
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2727 |
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- A.V. Grigoriev, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, S.A. Nikitin, D.M. Nikolenko, I.A. Rachek, Y.V. Shestakov, D.K. Toporkov, V.N. Zhilich
BINP SB RAS, Novosibirsk
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A method for beam polarization measurement in a storage ring has been for the first time developed and applied based on measuring the asymmetry in scattering of polarized beam electrons on the internal polarized gas jet target. Using this method we have studied the polarization in VEPP-3 booster storage ring. VEPP-3 is the source of polarized beams for VEPP-4M electron-positron collider in the planned experiment on high-precision mass measurement of tau-lepton near the production threshold of the latter (1777 MeV). Radiative polarization of beams obtained in VEPP-3 is used for absolute calibration of particle energy by the resonant depolarization technique after injection into VEPP-4M ring. The polarimeter design is described. Results of polarization measurements performed in 60 MeV range of VEPP-3 energy contiguous from above to tau-lepton production threshold are presented and discussed. The depolarizing influence of the integer machine spin resonance (1763 MeV) as well as of the combination spin resonances with the betatron frequencies are found to be significant.
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