Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0908.1501

Enhancement in Ground State Antihydrogen Formation via Three Body Recombination through Multiphoton effects

S. Ghosh Deb, Chittaranjan Sinha

Published Aug 11, 2009• 0 citations
arXivHTMLPDF

Abstract

Laser- assisted antihydrogen formation cross sections (differential and total) via the three - body recombination (TBR) process in a plasma of antiprotons and positrons are studied for the ground and excited states . Significantly large cross sections are obtained for low energies. The ground state antihydrogen cross section dominates throughout the energy range, essential for high precision spectroscopics studies in order to test the CPT theorem. The formation cross section are found to be much higher for unequal energies of the two positrons than for equal energies.

DOI
10.48550/arxiv.0908.1501

Related papers

Multiphoton effects in three-body recombination for antihydrogen formation

S. Ghosh Deb, Chittaranjan Sinha

Laser-assisted multiphoton cross-sections for the formation of antihydrogen ( ) via the three-body recombination (TBR) process in a plasma of antiprotons ( 's) and positrons ( e + 's) are studied for the ground and excited states (n=2 level). Significantly large enhancement is noted due to multiphoton effects particularly in the ground-state formation cross-section at lower incident energies with respect to the field-free case. The multiphoton ground-state cross-section dominates almost throughout the energy range (except at extreme low energies) in contrast to the field-free case. The formation cross-sections are found to be much higher for unequal energies of the two incident (active and spectator) e + 's than for equal energies.

Europhysics Letters (EPL)•Oct 1, 2009•1 citation

Formation of antihydrogen in three-body antiproton-positron collisions

Sumalay Roy, S. Ghosh Deb, Chittaranjan Sinha

A quantum-mechanical approach is proposed for the formation of antihydrogen $(\overline{H})$ in the ground and excited states $(2s,2p)$ via the mechanism of three-body recombination (TBR) inside a trapped plasma of antiprotons $(\overline{p})$ and positrons $({e}^{+})$ or in the collision between the two beams of them. Variations of the differential as well as the total formation cross sections are studied as a function of the incident energies of both the active and the spectator ${e}^{+}$'s. Significantly large cross sections are found at very low incident energies in the TBR process as compared to other processes leading to antihydrogen. The present $(\overline{H})$ formation cross section decreases with increasing positron energy (temperature) but no simple power law could be predicted for it covering the entire energy range $(\ensuremath{\sim}5--50\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$, corroborating the experimental findings qualitatively, the latter being at a much lower energy regime $(\ensuremath{\sim}{10}^{\ensuremath{-}4}\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$. The formation cross sections are found to be much higher for unequal energies of the two ${e}^{+}$'s than for equal energies, as expected physically.

arXiv:0803.3673•Physical Review A•Aug 8, 2008•5 citations

Collisions between anti-particles in presence of laser field

Chittaranjan Sinha, S. Ghosh Deb

Three body recombination (TBR) process for the formation of antihydrogen () inside a trapped plasma of antiprotons () and positrons (e+), supposed to be the most efficient mechanism for the production of cold and trapped antihydrogen is studied quantum mechanically. Present study also involves a background laser field anticipating further enhancement of the formation cross sections. Significantly large cross sections are obtained in the presence of the field at lower incident energies as compared to the field free ones. Cross sections are enhanced for higher excited states of ().

Journal of Physics Conference Series•Sep 1, 2009•0 citations

Formation of antihydrogen in an antiproton-positron Debye plasma in the presence of an external laser field

Sougata Mukhopadhyay, Chittaranjan Sinha

We study quantum mechanically the influence of an external laser field on the antihydrogen ($\overline{\mathrm{H}}$) formation cross sections in ground and excited states (2$s$,2$p$) via the three-body recombination process inside a dense plasma of antiprotons and positrons, supposed to be the most efficient mechanism for cold and trapped antihydrogen. The plasma screening is considered in the framework of a Debye- H\"uckel potential. The laser polarization is chosen to be parallel to the incident momentum of the passive positron. The modifications due to the presence of the laser field are found to be quite significant both quantitatively and qualitatively for all the states. In the presence of a laser, the $\overline{\mathrm{H}}$ formation cross sections are found to be suppressed significantly with respect to the field-free situation particularly in the ground state, while the excited state cross sections are in general enhanced at very low incident energies but are again suppressed at higher energies except for some special cases. The sensitivity of the formation cross sections with respect to the Debye length are also studied both in the laser-assisted and in the field-free situations. At very low incident energies, the ground state multiphoton formation is found to enhance with the increase in Debye screening, while the reverse is true for the excited states. These findings should have important implications for future $\overline{\mathrm{H}}$ studies.

Physical Review A•Sep 11, 2013•10 citations

Laser-assisted antihydrogen formation

Aparajeo Chattopadhyay, Chittaranjan Sinha

Laser-assisted antihydrogen $(\overline{\mathrm{H}})$ formation cross sections (differential and total) for collisions of antiprotons with positronium (Ps) are studied in the framework of the eikonal approximation for two geometries, when the field polarization is parallel $({\ensuremath{\Vert}}^{L})$ or perpendicular $({\ensuremath{\perp}}^{r})$ to the incident Ps momentum. The variations of the $\overline{\mathrm{H}}$ formation cross sections with respect to the field strength and the laser photon energy are studied for the multiphoton (absorption and emission) processes. The contribution of the atomic (both Ps and $\overline{\mathrm{H}}$) dressing terms to the enhancement of the $\overline{\mathrm{H}}$ formation cross section is studied for both the geometries (${\ensuremath{\Vert}}^{L}$ and ${\ensuremath{\perp}}^{r}$). The most important prediction from the present work is the enhancement of the field-free (FF) $\overline{\mathrm{H}}$ formation cross sections particularly at lower incident energies when the system $(\mathrm{Ps}+\overline{p})$ is irradiated by a single mode, linearly polarized laser, the enhancement being more pronounced for a wider range of incident energy in the ${\ensuremath{\perp}}^{r}$ geometry than in the ${\ensuremath{\Vert}}^{L}$ one.

Physical Review A•Aug 1, 2006•9 citations

Antihydrogen Formation and Level Population Evolution During Passage Through a Positron Plasma

B. Radics, Daniel J. Murtagh, Y. Yamazaki +1 more

Antihydrogen is at the focus of antimatter research.One of the main aims is to perform a direct test of the fundamental CPT symmetry by comparing the spectroscopic properties of the ground-state antihydrogen atom with those of the hydrogen atom.In current experiments synthetized antihydrogen is formed mainly via the three-body recombination process after mixing positron and antiproton clouds together in a cryogenic trap.The major three-body formation process populates mainly highly excited Rydberg states, therefore before the antihydrogen atoms reach the ground-state additional processes may take place, such as collisional (de)excitation, ionization and spontaneous or stimulated radiative transitions.We have used a classical-trajectory Monte Carlo (CTMC) code along with regular atomic codes to generate a scattering database of rate coefficients in various experimentally achievable magnetic field strengths and in low temperature positron plasma conditions.We used these rates to calculate the evolution of level population of antihydrogen during formation, scattering and flight within our experimental conditions [1].The model and the results are presented.

International Conference on Low Energy Antiproton Physics (LEAP)•Nov 23, 2017•0 citations
Laser- assisted antihydrogen formation cross sections (differential and total) via the three - body recombination (TBR) process in a plasma of antiprotons and positrons are studied for the ground and excited states . Significantly large cross sections are obtained for low energies. The ground state antihydrogen cross section dominates throughout the energy range, essential for high precision spectroscopics studies in order to test the CPT theorem. The formation cross section are found to be much higher for unequal energies of the two positrons than for equal energies.
Laser-assisted multiphoton cross-sections for the formation of antihydrogen ( ) via the three-body recombination (TBR) process in a plasma of antiprotons ( 's) and positrons ( e + 's) are studied for the ground and excited states (n=2 level). Significantly large enhancement is noted due to multiphoton effects particularly in the ground-state formation cross-section at lower incident energies with respect to the field-free case. The multiphoton ground-state cross-section dominates almost throughout the energy range (except at extreme low energies) in contrast to the field-free case. The formation cross-sections are found to be much higher for unequal energies of the two incident (active and spectator) e + 's than for equal energies.
A quantum-mechanical approach is proposed for the formation of antihydrogen (H‾)(\overline{H})(H) in the ground and excited states (2s,2p)(2s,2p)(2s,2p) via the mechanism of three-body recombination (TBR) inside a trapped plasma of antiprotons (p‾)(\overline{p})(p​) and positrons (e+)({e}^{+})(e+) or in the collision between the two beams of them. Variations of the differential as well as the total formation cross sections are studied as a function of the incident energies of both the active and the spectator e+{e}^{+}e+'s. Significantly large cross sections are found at very low incident energies in the TBR process as compared to other processes leading to antihydrogen. The present (H‾)(\overline{H})(H) formation cross section decreases with increasing positron energy (temperature) but no simple power law could be predicted for it covering the entire energy range $(\ensuremath{\sim}5--50\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$, corroborating the experimental findings qualitatively, the latter being at a much lower energy regime $(\ensuremath{\sim}{10}^{\ensuremath{-}4}\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$. The formation cross sections are found to be much higher for unequal energies of the two e+{e}^{+}e+'s than for equal energies, as expected physically.
Three body recombination (TBR) process for the formation of antihydrogen () inside a trapped plasma of antiprotons () and positrons (e+), supposed to be the most efficient mechanism for the production of cold and trapped antihydrogen is studied quantum mechanically. Present study also involves a background laser field anticipating further enhancement of the formation cross sections. Significantly large cross sections are obtained in the presence of the field at lower incident energies as compared to the field free ones. Cross sections are enhanced for higher excited states of ().
We study quantum mechanically the influence of an external laser field on the antihydrogen (H‾\overline{\mathrm{H}}H) formation cross sections in ground and excited states (2sss,2ppp) via the three-body recombination process inside a dense plasma of antiprotons and positrons, supposed to be the most efficient mechanism for cold and trapped antihydrogen. The plasma screening is considered in the framework of a Debye- H\"uckel potential. The laser polarization is chosen to be parallel to the incident momentum of the passive positron. The modifications due to the presence of the laser field are found to be quite significant both quantitatively and qualitatively for all the states. In the presence of a laser, the H‾\overline{\mathrm{H}}H formation cross sections are found to be suppressed significantly with respect to the field-free situation particularly in the ground state, while the excited state cross sections are in general enhanced at very low incident energies but are again suppressed at higher energies except for some special cases. The sensitivity of the formation cross sections with respect to the Debye length are also studied both in the laser-assisted and in the field-free situations. At very low incident energies, the ground state multiphoton formation is found to enhance with the increase in Debye screening, while the reverse is true for the excited states. These findings should have important implications for future H‾\overline{\mathrm{H}}H studies.
Laser-assisted antihydrogen (H‾)(\overline{\mathrm{H}})(H) formation cross sections (differential and total) for collisions of antiprotons with positronium (Ps) are studied in the framework of the eikonal approximation for two geometries, when the field polarization is parallel $({\ensuremath{\Vert}}^{L})$ or perpendicular $({\ensuremath{\perp}}^{r})$ to the incident Ps momentum. The variations of the H‾\overline{\mathrm{H}}H formation cross sections with respect to the field strength and the laser photon energy are studied for the multiphoton (absorption and emission) processes. The contribution of the atomic (both Ps and H‾\overline{\mathrm{H}}H) dressing terms to the enhancement of the H‾\overline{\mathrm{H}}H formation cross section is studied for both the geometries (${\ensuremath{\Vert}}^{L}$ and ${\ensuremath{\perp}}^{r}$). The most important prediction from the present work is the enhancement of the field-free (FF) H‾\overline{\mathrm{H}}H formation cross sections particularly at lower incident energies when the system (Ps+p‾)(\mathrm{Ps}+\overline{p})(Ps+p​) is irradiated by a single mode, linearly polarized laser, the enhancement being more pronounced for a wider range of incident energy in the ${\ensuremath{\perp}}^{r}$ geometry than in the ${\ensuremath{\Vert}}^{L}$ one.
Antihydrogen is at the focus of antimatter research.One of the main aims is to perform a direct test of the fundamental CPT symmetry by comparing the spectroscopic properties of the ground-state antihydrogen atom with those of the hydrogen atom.In current experiments synthetized antihydrogen is formed mainly via the three-body recombination process after mixing positron and antiproton clouds together in a cryogenic trap.The major three-body formation process populates mainly highly excited Rydberg states, therefore before the antihydrogen atoms reach the ground-state additional processes may take place, such as collisional (de)excitation, ionization and spontaneous or stimulated radiative transitions.We have used a classical-trajectory Monte Carlo (CTMC) code along with regular atomic codes to generate a scattering database of rate coefficients in various experimentally achievable magnetic field strengths and in low temperature positron plasma conditions.We used these rates to calculate the evolution of level population of antihydrogen during formation, scattering and flight within our experimental conditions [1].The model and the results are presented.