Česky
English
Výbor pro spolupráci ČR se Spojeným ústavem jaderných výzkumů Přihlášení
First Measurement of a Long-Lived pi(+) pi(-) Atom Lifetime

Autor
Afanasjev , Dr. SÚJV
Hons Zdeněk, RNDr. CSc.
Nikitin A.N. SÚJV
et al.  různé instituce

Rok
2019

Časopis
PHYSICAL REVIEW LETTERS 122 (8) 082003

Web


Obsah
The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike pi(+)pi(-) atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1 pm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n(A)(L) = 436(-61)(+157)vertical bar(tot) the lifetime of the 2p state is found to be QED tau(2p) = (0.45(-0.30)(+1.08) vertical bar(tot)) x 10(-11) s, not contradicting the corresponding QED 2p state lifetime r., -P 1.17 x 10(-11) s. This lifetime value is three orders of magnitude larger than our previously measured value of the pi(+) pi(-) atom ground state lifetime r = (3.15(-0.26)(+0.28)vertical bar(tot)) x 10(-15) s. Further studies of long-lived n-+ atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor Kin scattering lengths with the aim to check QCD predictions.

Příklad citace článku:
. Afanasjev, Z. Hons, A. Nikitin, . et al., "First Measurement of a Long-Lived pi(+) pi(-) Atom Lifetime ", PHYSICAL REVIEW LETTERS 122 (8) 082003 (2019)