Measurement of ∧› transverse polarization in e+ e- collisions at √ˆšs=3.68-3.71 GeV

• With data samples collected with the BESIII detector at seven energy points at√s = 3.68 − 3.71 GeV, corresponding to an integrated luminosity of 333 pb−1, we presenta study of the Λ transverse polarization in the e+e− → Λ¯Λ reaction. The significanceof polarization by combining the seven energy points is found to be 2.6σ including thesystematic uncertainty, which implies a non-zero phase between the transition amplitudesof the Λ¯Λ helicity states. The modulus ratio and the relative phase of EM-psionic formfactors combined with all energy points are measured to be RΨ = 0.71+0.10−0.10 ± 0.03 and ∆ΦΨ= 23+8.8−8.0 ± 1.6◦, where the first uncertainties are statistical and the second systematic.

Ämnesord

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Nyckelord

e+-e−Experiments

Electroweak Interaction

Polarization

Publikations- och innehållstyp

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