Spectroscopic tests for short-range modifications of Newtonian and post-Newtonian potentials

Abstract

There are theoretical frameworks, such as the large extra dimension models, which predict the strengthening of the gravitational field in short distances. Here we obtain new empiric constraints for deviations of standard gravity in the atomic length scale from analyses of recent and accurate data of hydrogen spectroscopy. The new bounds, extracted from 1S − 3S transition, are compared with previous limits given by antiprotonic Helium spectroscopy. Independent constraints are also determined by investigating the effects of gravitational spin-orbit coupling on the atomic spectrum.We show that the analysis of the influence of that interaction, which is responsible for the spin precession phenomena, on the fine structure of the states can be employed as a test of a post-Newtonian potential in the atomic domain. The constraints obtained here from 2P 1/2 − 2P 3/2 transition in hydrogen are tighter than previous bounds determined from measurements of the spin precession in an electron-nucleus scattering.

Recent results of laser spectroscopy experiments of pionic helium atoms at PSI

“…We found that the rate of 3 h −1 of detected resonant π 4 He + events is roughly compatible with the production rate of > 3 × 10 5 s −1 of the atoms and with Monte Carlo simulations [5] that were carried out by assuming that most of the metastable population are captured into the parent state calculated by theory, collisional and power broadening [7] which are estimated to cause a contribution of ≈ 50 GHz, and the ≈ 10 GHz linewidth of the narrowband spectral component of the laser pulses. Some further broadening of this resonance may be caused by atomic collisions that shorten [6,62] the lifetime of the resonance daughter state (n, ) = (17,15). The spacing of 3.0 GHz [5,70] between the fine structure sublines that is expected from the interaction between the electron spin and the orbital angular momentum of π − cannot be resolved in our experiment since it is much smaller than the 33 GHz natural width of the resonance itself.…”

“…The experiments began by searching for the (n, l) = ( 16 the laser irradiation at t = 9 ns. The peak in the former spectrum at t = 9 ns here corresponds to the laser resonance signal of (17, 16)→ (17,15). From [9].…”

“…No significant signal was observed. The coupling of the resonance daughter state (n, ) = (17,14) to an electronically excited state of π 4 He + is theoretically expected to cause large scalar and tensor polarizabilities of amplitudes 4 × 10 4 and 70 atomic units, respectively [6], and this is believed to destabilize the daughter state against atomic collisions [60,61].…”

“…We searched for the transition (17, 16)→ (17,15). The time spectrum indicated by filled circles in Figure 26.3 (c) was measured by accumulating data from 2.5 × 10 7 π − arrivals with the laser wavelength tuned to λ ≈ 1631.4 nm.…”

“…This can help set upper limits on constraints on the muon antineutrino mass by laboratory experiments [13]. Some upper limits may also be set on any exotic force [14][15][16][17][18] that involves the π − , as has been done in the case of antiprotonic helium (pHe + ≡ p + He 2+ + e − ) atoms [19][20][21][22][23][24][25][26][27][28][29][30]. Unlike the pHe + case, the atomic structure of π 4 He + contains no hyperfine structure that arises from the spin-spin interaction between the spin-0 π − and 4 He nucleus [31,32].…”