Dimesoatom breakup in the Coulomb field

Afanasyev, L.; Gevorkyan, S. R.; Voskresenskaya, O. O.

doi:10.1140/epja/s10050-019-00017-7

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…The relative yield between atoms and Coulomb pairs [25] is expressed by the ratio of the above cross sections. Thus, the total number N A of produced A 2π is determined via the number of Coulomb pairs N C by the model-independent relation:…”

Section: Setup For Investigation Of Long-lived π + π − Atomsmentioning

confidence: 99%

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First Measurement of a Long-Lived π+π− Atom Lifetime

Adeva¹,

Afanasyev²,

Anania³

et al. 2019

Phys. Rev. Lett.

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The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like π + π − atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm and got broken up in the 2.1 µm thick platinum foil. Analysing the observed number of atomic pairs, n L A = 436 +157 −61 tot , the lifetime of the 2p state is found to be τ 2p = ( 0.45 +1.08 −0.30 tot ) · 10 −11 s, not contradicting the corresponding QED 2p state lifetime τ QED 2p = 1.17 · 10 −11 s. This lifetime value is three orders of magnitude larger than our previously measured value of the π + π − atom ground state lifetime τ = ( 3.15 +0.28 −0.26 tot ) · 10 −15 s. Further studies of long-lived π + π − atoms will allow to measure energy differences between p and s atomic states and so to determine ππ scattering lengths with the aim to check QCD predictions. (J.Schacher) 1 deceased cesses, these atoms are produced in s states distributed according to n −3 , n being the principal quantum number [8].The decay probability of short-lived π + π − atoms (A 2π , pionium) in s states is dominated (99.6%) by the annihilation process [9-13] π + + π − → π 0 + π 0 and is given by the ππ s-wave scattering lengths combination |a 0 − a 2 | (a I is the ππ scattering length for isospin I):

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Section: Setup For Investigation Of Long-lived π + π − Atomsmentioning

confidence: 99%

“…where N C (q ≤ q 0 ) is the number of Coulomb pairs with q ≤ q 0 and K(q 0 ) a known function of q 0 [25].…”

Section: Setup For Investigation Of Long-lived π + π − Atomsmentioning

confidence: 99%

First Measurement of a Long-Lived π+π− Atom Lifetime

Adeva¹,

Afanasyev²,

Anania³

et al. 2019

Phys. Rev. Lett.

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“…This paper is devoted to the memory of Alexander Tarasov, a remarkable scientist and person [27] 6 who owns a decisive contribution to the work [21].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Lindhard–Sørensen and Mott–Bloch Corrections to the Bethe Stopping Formula at Moderately Relativistic Energies

Kats

Halenka

Voskresenskaya

2021

Phys. Part. Nuclei Lett.

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The results of numerical calculating the total Mott−Bloch correction to the Bethe stopping formula and the Lindhard−Sørensen correction in the point nucleus approximation, as well as the Mott correction and the difference between the Lindhard−Sørensen and Bloch corrections, which were obtained by some rigorous and approximate methods, are compared for the ranges of a gamma factor 1 ≲ 𝛾 ≲ 10 and the ion nuclear charge number 6 ≤ Z ≤ 114. It is shown that the accurate calculation of the Mott−Bloch correction based on the Mott exact cross section using a method previously proposed by one of the authors gives excellent agreement between its values and the values of the Lindhard−Sørensen correction in the 𝛾 and Z ranges under consideration. In addition, it is demonstrated that the results of stopping power calculations obtained by the two above-mentioned rigorous methods coincide with each other up to the seventh significant digit and provide the best agreement with experimental data in contrast with the results of some approximate methods, such as the methods of Ahlen, Jackson−McCarthy, etc.

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The Pionic Deuterium and the Pion Tetrahedron Vacuum Polarization

Rom

2024

JHEPGC

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A double-well potential model is proposed for the pionic deuterium that enables to calculate the energy split, the potential barrier height and estimate the pion tetrahedron edge length. We propose that pion tetrahedrons, Td uddu π =   , play a central role in the Yukawa interaction by enabling quark exchange reactions between protons and neutrons by tunneling through a potential barrier. A vacuum polarization Feynman diagram is proposed for the Td π having chains of fermion loops for the two valence quarks and anti-quarks connected by gluons. With a higher order vacuum polarization diagram, the d and u quark loops are interleaved and the chiral symmetry is broken dynamically. The proposed Td π vacuum polarization integral does not diverge in both the IR and UV limits and vanishes in the limit of an infinite pion tetrahedron condensate. We propose a new Delbruck scattering Feynman diagram that includes d and u quark and anti-quark interleaved loops. We further propose that conversion of gravitons to photons may occur via quark and anti-quark loops that describe the pion tetrahedrons dynamics in the vacuum and may also transfer gravitational waves.

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Dimesoatom breakup in the Coulomb field

Cited by 3 publications

References 15 publications

First Measurement of a Long-Lived π+π− Atom Lifetime

First Measurement of a Long-Lived π+π− Atom Lifetime

Comparison of the Lindhard–Sørensen and Mott–Bloch Corrections to the Bethe Stopping Formula at Moderately Relativistic Energies

The Pionic Deuterium and the Pion Tetrahedron Vacuum Polarization

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