Thresholds of ultraperipheral processes

Dremin, I.

doi:10.1142/s0217751x20500876

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…At the same time, it is desirable to learn these processes at conditions closest to astrophysics requirements. In particular, the energies of NICA collider are above the threshold of dielectrons production but lower than the threshold for dimuons [18]. That is why we demonstrate here the properties of positronia (and 511 keV photons) and dielectrons just in this energy interval from 5 GeV to 11 GeV per nucleon in the center of mass system.…”

Section: Ultraperipheral Nuclear Collisions At Nica Collidermentioning

confidence: 55%

Positronia' clouds in Universe

Dremin¹

2021

Preprint

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The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia' clouds. Unbound electron-positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favours abundant creation of the unbound electron-positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z 4 (Z is the electric charge of a heavy ion) compared to protons with Z=1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e + e − -pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.

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Section: Ultraperipheral Nuclear Collisions At Nica Collidermentioning

confidence: 55%

Positronia' clouds in Universe

Dremin¹

2021

Preprint

Self Cite

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show abstract

“…The energy region of NICA from 5 to 11 GeV per a nucleon pair in the center of mass system is especially suitable for our purposes. It lies above the threshold for positronia and e + e − -production in ultraperipheral processes but below the thresholds for heavier dileptons [21]. The cross sections of such processes are quite large already within these energies while no background from higher mass dileptons appears.…”

Section: Ultraperipheral Nuclear Collisions At Nica Collidermentioning

confidence: 88%

Positronia’ Clouds in Universe

Dremin

2021

Universe

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The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia clouds. Unbound electron–positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favors abundant creation of the unbound electron–positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore, we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z4 (Z is the electric charge of a heavy ion) compared to protons with Z = 1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e+e−-pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.

show abstract

Nonequilibrium Properties of Quark–Gluon Matter at NICA Energies

Dremin

2021

Phys. Part. Nuclei

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Thresholds of ultraperipheral processes

Cited by 3 publications

References 25 publications

Positronia' clouds in Universe

Positronia' clouds in Universe

Positronia’ Clouds in Universe

Nonequilibrium Properties of Quark–Gluon Matter at NICA Energies

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