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Masaki Hori - One of the best experts on this subject based on the ideXlab platform.
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method for laser spectroscopy of metastable pionic Helium atoms
Hyperfine Interactions, 2015Co-Authors: Masaki Hori, Anna Sótér, Daniel Barna, Hossein Aghaikhozani, R S Hayano, Y Murakami, Hiroyuki YamadaAbstract:The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic Helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a Helium Nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic Helium atoms at CERN.
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proposed method for laser spectroscopy of pionic Helium atoms to determine the charged pion mass
Physical Review A, 2014Co-Authors: Masaki Hori, Anna Sótér, V I KorobovAbstract:Metastable pionic Helium ($\ensuremath{\pi}{\mathrm{He}}^{+}$) is a three-body atom composed of a Helium Nucleus, an electron occupying the 1$s$ ground state, and a negatively charged pion ${\ensuremath{\pi}}^{\ensuremath{-}}$ in a Rydberg state with principal and orbital angular momentum quantum numbers of $n\ensuremath{\sim}\ensuremath{\ell}+1\ensuremath{\sim}16$. We calculate the spin-independent energies of the $\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}{{}^{3}\mathrm{He}}^{+}$ and $\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}{{}^{4}\mathrm{He}}^{+}$ isotopes in the region $n=15$--19. These include relativistic and quantum electrodynamics corrections of orders ${R}_{\ensuremath{\infty}}{\ensuremath{\alpha}}^{2}$ and ${R}_{\ensuremath{\infty}}{\ensuremath{\alpha}}^{3}$ in atomic units, where ${R}_{\ensuremath{\infty}}$ and $\ensuremath{\alpha}$ denote the Rydberg and fine structure constants. The fine-structure splitting due to the coupling between the electron spin and the orbital angular momentum of the ${\ensuremath{\pi}}^{\ensuremath{-}}$ and the radiative and Auger decay rates of the states are also calculated. Some states $(n,\ensuremath{\ell})=(16,15)$ and $(17,16)$ retain nanosecond-scale lifetimes against ${\ensuremath{\pi}}^{\ensuremath{-}}$ absorption into the Helium Nucleus. We propose the use of laser pulses to induce ${\ensuremath{\pi}}^{\ensuremath{-}}$ transitions from these metastable states to states with large ($\ensuremath{\sim}{10}^{11}$ s${}^{\ensuremath{-}1}$) Auger rates. The $\ensuremath{\pi}{\mathrm{He}}^{2+}$ ion that remains after Auger emission of the 1$s$ electron undergoes Stark mixing with the $s$, $p$, and $d$ states during collisions with the Helium atoms in the experimental target. This leads to immediate nuclear absorption of the ${\ensuremath{\pi}}^{\ensuremath{-}}$. The resonance condition between the laser beam and the atom is thus revealed as a sharp spike in the rates of neutrons, protons, deuterons, and tritons that emerge. A resonance curve is obtained from which the $\ensuremath{\pi}{\mathrm{He}}^{+}$ transition frequency can in principle be determined with a fractional precision of ${10}^{\ensuremath{-}8}--{10}^{\ensuremath{-}6}$ provided the systematic uncertainties can be controlled. By comparing the measured $\ensuremath{\pi}{\mathrm{He}}^{+}$ frequencies with the calculated values, the ${\ensuremath{\pi}}^{\ensuremath{-}}$ mass may be determined with a similar precision. The $\ensuremath{\pi}{\mathrm{He}}^{+}$ will be synthesized by allowing a high-intensity ($g{10}^{8}$ s${}^{\ensuremath{-}1}$) beam of ${\ensuremath{\pi}}^{\ensuremath{-}}$produced by a cyclotron to come to rest in a Helium target. The precise time structure of the ${\ensuremath{\pi}}^{\ensuremath{-}}$ beam is used to ensure a sufficient rate of coincidence between the resonant laser pulses and the $\ensuremath{\pi}{\mathrm{He}}^{+}$ atoms.
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two photon laser spectroscopy of antiprotonic Helium and the antiproton to electron mass ratio
Nature, 2011Co-Authors: Masaki Hori, Anna Sótér, R S Hayano, E Widmann, D Barna, A Dax, S Friedreich, B Juhasz, T Pask, Dezső HorvathAbstract:The principle of CPT (charge, parity, time) symmetry implies that antimatter particles have exactly the same mass and absolute value of charge as their particle counterparts. Hori et al. test this principle by performing high-precision, two-photon spectroscopy of antiprotonic Helium. By comparing the results with calculations, they derive a value for the antiproton-to-electron mass ratio, the first time this quantity has been determined. The result agrees with the proton-to-electron value known to a similar precision. Moreover, the work improves the accuracy with which the charge-to-mass ratio of the antiproton can be compared to that of the proton by four orders of magnitude. Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry1). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic Helium ( He+) is a three-body atom2 consisting of a normal Helium Nucleus, an electron in its ground state and an antiproton ( ) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n ≈ l + 1 ≈ 38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic Helium, in which 3He+ and 4He+ isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l) → (n − 2, l − 2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0 nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3–5 parts in 109. By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.
Anna Sótér - One of the best experts on this subject based on the ideXlab platform.
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method for laser spectroscopy of metastable pionic Helium atoms
Hyperfine Interactions, 2015Co-Authors: Masaki Hori, Anna Sótér, Daniel Barna, Hossein Aghaikhozani, R S Hayano, Y Murakami, Hiroyuki YamadaAbstract:The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic Helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a Helium Nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic Helium atoms at CERN.
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proposed method for laser spectroscopy of pionic Helium atoms to determine the charged pion mass
Physical Review A, 2014Co-Authors: Masaki Hori, Anna Sótér, V I KorobovAbstract:Metastable pionic Helium ($\ensuremath{\pi}{\mathrm{He}}^{+}$) is a three-body atom composed of a Helium Nucleus, an electron occupying the 1$s$ ground state, and a negatively charged pion ${\ensuremath{\pi}}^{\ensuremath{-}}$ in a Rydberg state with principal and orbital angular momentum quantum numbers of $n\ensuremath{\sim}\ensuremath{\ell}+1\ensuremath{\sim}16$. We calculate the spin-independent energies of the $\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}{{}^{3}\mathrm{He}}^{+}$ and $\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}{{}^{4}\mathrm{He}}^{+}$ isotopes in the region $n=15$--19. These include relativistic and quantum electrodynamics corrections of orders ${R}_{\ensuremath{\infty}}{\ensuremath{\alpha}}^{2}$ and ${R}_{\ensuremath{\infty}}{\ensuremath{\alpha}}^{3}$ in atomic units, where ${R}_{\ensuremath{\infty}}$ and $\ensuremath{\alpha}$ denote the Rydberg and fine structure constants. The fine-structure splitting due to the coupling between the electron spin and the orbital angular momentum of the ${\ensuremath{\pi}}^{\ensuremath{-}}$ and the radiative and Auger decay rates of the states are also calculated. Some states $(n,\ensuremath{\ell})=(16,15)$ and $(17,16)$ retain nanosecond-scale lifetimes against ${\ensuremath{\pi}}^{\ensuremath{-}}$ absorption into the Helium Nucleus. We propose the use of laser pulses to induce ${\ensuremath{\pi}}^{\ensuremath{-}}$ transitions from these metastable states to states with large ($\ensuremath{\sim}{10}^{11}$ s${}^{\ensuremath{-}1}$) Auger rates. The $\ensuremath{\pi}{\mathrm{He}}^{2+}$ ion that remains after Auger emission of the 1$s$ electron undergoes Stark mixing with the $s$, $p$, and $d$ states during collisions with the Helium atoms in the experimental target. This leads to immediate nuclear absorption of the ${\ensuremath{\pi}}^{\ensuremath{-}}$. The resonance condition between the laser beam and the atom is thus revealed as a sharp spike in the rates of neutrons, protons, deuterons, and tritons that emerge. A resonance curve is obtained from which the $\ensuremath{\pi}{\mathrm{He}}^{+}$ transition frequency can in principle be determined with a fractional precision of ${10}^{\ensuremath{-}8}--{10}^{\ensuremath{-}6}$ provided the systematic uncertainties can be controlled. By comparing the measured $\ensuremath{\pi}{\mathrm{He}}^{+}$ frequencies with the calculated values, the ${\ensuremath{\pi}}^{\ensuremath{-}}$ mass may be determined with a similar precision. The $\ensuremath{\pi}{\mathrm{He}}^{+}$ will be synthesized by allowing a high-intensity ($g{10}^{8}$ s${}^{\ensuremath{-}1}$) beam of ${\ensuremath{\pi}}^{\ensuremath{-}}$produced by a cyclotron to come to rest in a Helium target. The precise time structure of the ${\ensuremath{\pi}}^{\ensuremath{-}}$ beam is used to ensure a sufficient rate of coincidence between the resonant laser pulses and the $\ensuremath{\pi}{\mathrm{He}}^{+}$ atoms.
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two photon laser spectroscopy of antiprotonic Helium and the antiproton to electron mass ratio
Nature, 2011Co-Authors: Masaki Hori, Anna Sótér, R S Hayano, E Widmann, D Barna, A Dax, S Friedreich, B Juhasz, T Pask, Dezső HorvathAbstract:The principle of CPT (charge, parity, time) symmetry implies that antimatter particles have exactly the same mass and absolute value of charge as their particle counterparts. Hori et al. test this principle by performing high-precision, two-photon spectroscopy of antiprotonic Helium. By comparing the results with calculations, they derive a value for the antiproton-to-electron mass ratio, the first time this quantity has been determined. The result agrees with the proton-to-electron value known to a similar precision. Moreover, the work improves the accuracy with which the charge-to-mass ratio of the antiproton can be compared to that of the proton by four orders of magnitude. Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry1). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic Helium ( He+) is a three-body atom2 consisting of a normal Helium Nucleus, an electron in its ground state and an antiproton ( ) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n ≈ l + 1 ≈ 38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic Helium, in which 3He+ and 4He+ isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l) → (n − 2, l − 2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0 nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3–5 parts in 109. By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.
Shant Shahbazian - One of the best experts on this subject based on the ideXlab platform.
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deciphering the chemical nature of the exotic isotopes of hydrogen by the mc qtaim analysis the positively charged muon and the muonic Helium as new members of the periodic table
Physical Chemistry Chemical Physics, 2014Co-Authors: Mohammad Goli, Shant ShahbazianAbstract:This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic Helium, i.e., the negatively charged muon plus Helium Nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born–Oppenhiemer wavefunctions. Accordingly, the “atoms in molecules” analysis performed on various asymmetric exotic isotopomers of the hydrogen molecule, recently detected experimentally [Science, 2011, 331, 448], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atoms. Various derived properties of atomic basins containing the muonic Helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization. However, with some tolerance, they may also be categorized as hydrogen basins though with a smaller electronegativity. All in all, the present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, which are difficult to elucidate by experimental and/or alternative theoretical schemes.
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deciphering the chemical nature of the exotic isotopes of hydrogen by the mc qtaim analysis the positively charged muon and the muonic Helium as new members of the periodic table
arXiv: Chemical Physics, 2013Co-Authors: Mohammad Goli, Shant ShahbazianAbstract:This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic Helium, i.e., the negatively charged muon plus Helium Nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions. Accordingly, the "atoms in molecules" analysis performed on various asymmetric exotic isotopomers of hydrogen molecule, recently detected experimentally [Science 331, 448 (2011)], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atom. Various derived properties of atomic basins containing muonic Helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization; however, with some tolerance, they may be categorized also as hydrogen basins though with a smaller electronegativity. All in all, present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, hard to be elucidated by experimental and/or alternative theoretical schemes.
R S Hayano - One of the best experts on this subject based on the ideXlab platform.
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Effects of impurity molecules on the lifetime of antiprotonic Helium atoms
2020Co-Authors: Juh B A Asz, R S Hayano, E Widmann, J Eades, M Hori, D Horv, T Ishikawa, H A Torii, H Yamaguchi, T YamazakiAbstract:Abstract Quenching of metastable antiprotonic Helium atoms in collisions with hydrogen and deuterium molecules has been studied using laser spectroscopy at CERNÕs antiproton decelerator. The temperature dependence of the quenching cross sections of the antiprotonic states ðn; lÞ ¼ ð37; 34Þ, ð38; 35Þ and ð38; 37Þ has been investigated and a deviation from the Arrhenius law was found at low temperatures. In case of the state ð38; 37Þ with deuterium, detailed measurements revealed that the quenching cross section levels off at low temperatures indicating a strong quantum tunneling effect. Ó 2003 Elsevier B.V. All rights reserved. PACS: 36.10.)k; 34.20.Gj; 82.20.Xr Keywords: Quantum tunneling; Antiprotonic Helium; Hydrogen; Deuterium; Temperature dependence of quenching cross section An antiprotonic Helium atom is an exotic three-body system consisting of an antiproton, an electron and a Helium Nucleus ( p pHe þ p p À e À À He 2þ ). Various properties of these atoms (transition energies, state lifetimes etc.) have been extensively studied in the past years using a laser spectroscopy method According to the theoretical calculations of Sauge and Valiron, an ðn; lÞ-dependent activation barrier exists for this kind of reaction which could explain the observed quenching behaviour where r 0 is the cross section at infinitely high temperatures (this we expect to be close to the geometrical cross section), E b is the height of the activation barrier, k is the Boltzmann constant and T is the temperature. However, all previous measurements of quenching by hydrogen and deuterium molecules were done at 30 K; therefore in 2002 we measured the quenching cross sections of three metastable antiprotonic states at higher temperatures to test the above temperature dependence and possibly determine the reaction barrier heights. These measurements, together with the theoretical calculations, can give us a better understanding of the physico-chemistry of cold interstellar and protostellar clouds where similar low temperature reactions play a significant role, especially various hydrogen/deuterium fractionation processes that cause enrichment of deuterium in these environments. The quenching cross section of a metastable antiprotonic state can be obtained by measuring the decay rate of the state at different impurity concentrations using laser spectroscopy. Assuming that the antiprotonic Helium atoms are quenched in binary collisions with the impurity molecules, the decay rate cðn; lÞ of the state then can be expressed as cðn; lÞ ¼ c 0 ðn; lÞ þ n imp v th r q ðn; lÞ; ð2Þ where c 0 ðn; lÞ is the ÔintrinsicÕ decay rate of the state in pure Helium which can be calculated theoretically, n imp is the number density of the impurity molecules, is the relative velocity of the colliding molecules The decay rate of a metastable state can be measured using two methods which are based on the same laser spectroscopy method. Antiprotonic states can be either long-lived metastable states from where antiprotons can de-excite to lowerlying states by emitting a photon, or short-lived states from where antiprotons annihilate on the Helium Nucleus. Due to this difference in the lifetime, short-lived states have very small antiproton population compared to long-lived states. Antiprotons in a long-lived metastable state can be efficiently stimulated by a laser pulse to make a transition to a short-lived state if we choose a transition that satisfies the rules Dn ¼ AE1 and Dl ¼ AE1. Under such conditions, a laser pulse tuned to a metastable-to-short-lived transition and fired into the target containing p pHe þ atoms will produce a peak in the annihilation time spectrum of the antiprotons, since it suddenly increases the population of the short-lived state. If the state whose quenching cross section we want to measure can be the parent state of such a metastable-toshort-lived laser-induced transition, then the decay rate c of the state can be obtained in the following way. We measure the area of the laser-induced peak in the antiproton annihilation time spectrum (normalized to the total background) at different laser firing times. Since the area of the peak is proportional to the population of the parent state at the time of the laser firing, this way we obtain the population lifetime s p of the parent state. If feeding to this state from upper states is negligible, then the inverse of this lifetime is equal to the decay rate of the state: c ¼ 1=s p . This is the Ôt1-scanÕ method If the state is not accessible with an ordinary laser-induced transition described above, the hydrogen-assisted inverse resonance (HAIR) or deuterium-assisted inverse resonance (DAIR) methods can be used Our gas target consisted of 4 He to which hydrogen or deuterium was premixed at molar concentrations of 30-10,000 ppm. We used a cryogenic target chamber for the measurements between 25 and 100 K, and another target chamber with a larger target volume for the room temperature measurements. Both chambers have a stainless steel window on the upstream wall for the antiproton beam, and a quartz window on the downstream wall for the laser beam. The temperature of the cryogenic target was measured with a silicon diode sensor with an uncertainty of 1 K. The temperature of the room temperature target was not measured directly so an uncertainty of 2 K was assigned in these cases. The absolute number density of the H 2 and D 2 molecules was varied not only by changing gas mixture but also by changing the pressure of the gas target between 1 and 8 bar. Although increasing pressure decreases the lifetime of metastable states, this effect is negligible compared to the lifetime shortening caused by the increasing density of the H 2 and D 2 molecules We determined the decay rates of the following metastable antiprotonic states: ðn; lÞ ¼ ð37; 34Þ with hydrogen and deuterium using the transition ð37; 34Þ ! ð36; 33Þ with the t1-scan method, ð38; 35Þ with hydrogen and deuterium using the transition ð37; 34Þ ! ð38; 35Þ with the HAIR/ DAIR method, and ð38; 37Þ with hydrogen and deuterium using the transition ð37; 36Þ ! ð38; 37Þ with the HAIR/DAIR method. If the decay rates measured at a given temperature and for a given antiprotonic state and the theoretically calculated decay rate in pure Helium (i.e. at n imp ¼ 0) where r t is independent of the temperature. The term r t in Eq. (3) is most likely related to the quantum tunneling of the colliding molecule through the activation barrier, as suggested by Sauge and Valiron The geometrical cross section of the D 2 -He collision is 21 · 10 À16 cm
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method for laser spectroscopy of metastable pionic Helium atoms
Hyperfine Interactions, 2015Co-Authors: Masaki Hori, Anna Sótér, Daniel Barna, Hossein Aghaikhozani, R S Hayano, Y Murakami, Hiroyuki YamadaAbstract:The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic Helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a Helium Nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic Helium atoms at CERN.
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two photon laser spectroscopy of antiprotonic Helium and the antiproton to electron mass ratio
Nature, 2011Co-Authors: Masaki Hori, Anna Sótér, R S Hayano, E Widmann, D Barna, A Dax, S Friedreich, B Juhasz, T Pask, Dezső HorvathAbstract:The principle of CPT (charge, parity, time) symmetry implies that antimatter particles have exactly the same mass and absolute value of charge as their particle counterparts. Hori et al. test this principle by performing high-precision, two-photon spectroscopy of antiprotonic Helium. By comparing the results with calculations, they derive a value for the antiproton-to-electron mass ratio, the first time this quantity has been determined. The result agrees with the proton-to-electron value known to a similar precision. Moreover, the work improves the accuracy with which the charge-to-mass ratio of the antiproton can be compared to that of the proton by four orders of magnitude. Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry1). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic Helium ( He+) is a three-body atom2 consisting of a normal Helium Nucleus, an electron in its ground state and an antiproton ( ) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n ≈ l + 1 ≈ 38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic Helium, in which 3He+ and 4He+ isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l) → (n − 2, l − 2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0 nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3–5 parts in 109. By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.
Hiroyuki Yamada - One of the best experts on this subject based on the ideXlab platform.
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method for laser spectroscopy of metastable pionic Helium atoms
Hyperfine Interactions, 2015Co-Authors: Masaki Hori, Anna Sótér, Daniel Barna, Hossein Aghaikhozani, R S Hayano, Y Murakami, Hiroyuki YamadaAbstract:The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic Helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a Helium Nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic Helium atoms at CERN.