Neutral Kaon Mass Measurement with CMD2 Detector Alexander

Neutral Kaon Mass Measurement with CMD-2 Detector Alexander Zaytsev http: //cmd. inp. nsk. su/~azaitsev Novosibirsk, Budker INP SB RAS On behalf of CMD 2 Collaboration http: //cmd. inp. nsk. su DAFNE 2004 @ Frascati, Italy

VEPP-2 M Collider at Budker INP (Novosibirsk) VEPP-2 M average beam energy was calibrated using resonant depolarization technique

CMD-2 General Purpose Detector at VEPP-2 M Collider

Review of M(KS) Measurement Techniques Absolute pion momentum calibration technique: Critical pion opening angle technique: Full kaon decay reconstruction technique: and also could be represented by with CMD-2 choice

Kaon Decay Kinematics KS Decay Samples Full kaon decay Critical opening reconstruction angle technique Asymmetry cut

Systematic Effects and Corrections to Visible Mass Values (Initial State Radiation) Radiative Correction applied to compensate C. M. energy shift caused by ISR w RC (ISR) Nonlinearity Correction applied to take into account finite angular and momentum resolution effects w NC Bin-by-detector Electron-positron beams Energy Spread correction applied to Bin take into account initial particles energy distribution in w ES VEPP-2 M storage ring Charged pions energy losses (d. E/dx) in CMD-2 detector w DE Event-bymaterial (vacuum tube & DC) compensation Event. Compensate CMD-2 detector Magnetic Field experimentally measured nonunformity w MF (Final State Radiation) Radiative Correction applied to w RC (FSR) compensate reconstructed kaon mass shift caused by FSR Average value only A number of other negligibly small corrections w…