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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Pionium or A2pi is a hydrogen-like atom consisting of pi+ and pi- mesons. The goal of the DIRAC experiment at CERN (PS212) is to measure the pionium lifetime with $10\%$ precision. Such a measurement would yield a precision of 5% on the value of the S-wave pipi scattering lengths combination |a0 - a2| which is predicted to be a0 - a2 = 0.265 +- 0.004. Corresponded $A_{2\pi}$ lifetime is tau = (2.9 +- 0.1) 10**(-15) s