Limits on a nucleon–nucleon monopole–dipole coupling from spin relaxation of polarized ultra-cold neutrons in traps

We have studied the relaxation of a spin-polarized gas in a magnetic field, in the presence of short-range spin-dependent interactions. As a main result we have established a link between the specific properties of the interaction and the dependence of the spin-relaxation rate on the magnitude of the holding magnetic field. This allows us to formulate a new, extremely sensitive method to study (pseudo) magnetic properties at the submillimeter scale, which are difficult to access by other means. The method has been used as a probe for nucleon-nucleon axionlike P, T violating interactions which yields a two-order-of-magnitude improved constraint on the coupling strength (g(s)g(p)) as a function of the force range (λ): g(s)g(p)λ² < 3×10⁻²⁷ m².

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“…With this replacement our expression (11) agrees with Ref. [23] obtained for ultracold neutron depolarization.…”

supporting

confidence: 87%

PolarizedHe3as a Probe for Short-Range Spin-Dependent Interactions

Petukhov¹,

Pignol²,

Jullien³

et al. 2010

Phys. Rev. Lett.

124

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“…The ability of slow neutrons to penetrate macroscopic amounts of matter and to interact coherently with the medium allow the quantum amplitudes governing their motion to accumulate large phase shifts which can be sensed with interferometric measurements [17][18][19]. These features of slow neutron interactions with matter and external fields have been exploited in a number of recent experiments which search for possible new weakly-coupled interactions of various types [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. This strategy can succeed despite the uncertainties in our knowledge of the neutron-nucleus strong interaction.…”

Section: Introduction and Theoretical Overviewmentioning

confidence: 99%

Internal consistency of neutron coherent scattering length measurements from neutron interferometry and from neutron gravity reflectometry

et al. 2020

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Many theories beyond the Standard Model postulate short-range modifications to gravity which produce deviations of Newton's gravitational potential from a strict 1/r dependence. It is common to analyze experiments searching for these modifications using a potential of the formThe best present constraints on α for λ < 100 nm come from neutron scattering and often employ comparisons of different measurements of the coherent neutron scattering amplitudes b. We analyze the internal consistency of existing data from two different types of measurements of low energy neutron scattering amplitudes: neutron interferometry, which involves momentum transfers q 2 = 0, and neutron gravity reflectometry, which involves momentum transfers q 2 = 8mVopt where m is the neutron mass and Vopt is the neutron optical potential of the medium. We show that the fractional difference ∆b |b| averaged over the 7 elements where high precision data exists on the same material from both measurement methods is [2.2 ± 1.4] × 10 −4 . We also show that ∆b |b| for this data is insensitive both to exotic Yukawa interactions and also to the electromagnetic neutron-atom interactions proportional to the neutron-electron scattering length bne and the neutron polarizability scattering amplitude b pol . This result will be useful in any future global analyses of neutron scattering data to determine bne and bound α and λ. We also discuss how various neutron interferometric and scattering techniques with cold and ultracold neutrons can be used to improve the precision of b measurements and make some specific proposals.

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“…Most of the experiments which have been performed to search for such interactions [10][11][12][13][14][15] are sensitive to ranges λ ≥ 1 cm. Constraints on monopole-dipole interactions involving nucleons at smaller range have come from experiments using slow neutrons [16][17][18][19] and polarized helium and xenon gas [20][21][22][23][24][25][26]. Torsion balance measurements have recently set new stringent limits on possible monopole-dipole interactions involving polarized electrons [27] and further work is in progress.…”

Section: Introductionmentioning

confidence: 99%

Searches for Exotic Spin-Dependent Interactions of Slow Neutrons with Matter using Neutron Spin Rotation

Snow

Heckel²,

Penn³

et al. 2015

Proceedings of the 2nd International Symposium on Science at J-Parc — Unlocking the Mysteries of Life, Matter and the Universe

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Polarized slow neutrons can be used to conduct sensitive searches for subtle spin-dependent neutron interactions in matter. A brief overview of the theoretical context in which such searches are important is given. We present the result of a recent measurement of neutron spin rotation in liquid helium that constrains possible exotic long-range parity-odd interactions between the neutron and matter from the exchange of spin 1 bosons of meV-scale masses. The experiment also places the first upper bound to our knowledge on what may be called "in-matter"gravitational torsion. Finally, we discuss a proposed search for a possible parity-even exotic interaction of polarized neutrons with matter from spin 1 boson exchange with axial couplings for boson masses in the meV range.

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Limits on a nucleon–nucleon monopole–dipole coupling from spin relaxation of polarized ultra-cold neutrons in traps

Cited by 24 publications

References 19 publications

PolarizedHe3as a Probe for Short-Range Spin-Dependent Interactions

PolarizedHe3as a Probe for Short-Range Spin-Dependent Interactions

Internal consistency of neutron coherent scattering length measurements from neutron interferometry and from neutron gravity reflectometry

Searches for Exotic Spin-Dependent Interactions of Slow Neutrons with Matter using Neutron Spin Rotation

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