Search for neutron–mirror neutron oscillations in a laboratory experiment with ultracold neutrons

Serebrov, A. P.; Aleksandrov, E. B.; Dovator, N. A.; Dmitriev, S. P.; Fomin, A. K.; Geltenbort, P.; Харитонов, А. Г.; Krasnoschekova, I. A.; Lasakov, M. S.; Murashkin, A. N.; Shmelev, G.E.; Varlamov, V. E.; Vassiljev, A. V.; Zherebtsov, O. M.; Zimmer, O.

doi:10.1016/j.nima.2009.07.041

Cited by 61 publications

(105 citation statements)

References 26 publications

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“…By introducing a six-quark coupling in the mirror matter theory for the n and n interaction of δm ∼ 10 −15 eV with a large mass cutoff at M ∼ 10 TeV, Berezhiani and Bento proposed a possible n − n oscillation mechanism with a time scale of τ ∼ 1 s [11]. Later on, such oscillations were refuted experimentally with a much higher constraint of τ ≥ 448 s [12,13,14,15]. Despite all these efforts over the years the neutron lifetime puzzle still eludes explanation.…”

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confidence: 99%

“…(4). For the "bottle" experiments, the magnetic field of the UCN trap varied from as low as B ≈ 2 nT up to 10 mT (including ambient Earth's magnetic field of about 50µT) [13,14,15,12,3] corresponding to an energy shift of 1.2 × 10 −16 − 6 × 10 −10 eV. If the n − n mass difference is large enough ( 6 × 10 −10 eV), the medium effect from the magnetic field will be negligible and meanwhile 1 2 ∆ nn τ f 1, i.e., the propagation factor of Eq.…”

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confidence: 99%

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Neutron oscillations for solving neutron lifetime and dark matter puzzles

Tan

2019

Physics Letters B

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A model of n − n (neutron-mirror neutron) oscillations is proposed under the framework of the mirror matter theory with slightly broken mirror symmetry. It resolves the neutron lifetime discrepancy, i.e., the 1% difference in neutron lifetime between measurements from "beam" and "bottle" experiments. In consideration of the early universe evolution, the n − n mass difference is determined to be about 2 × 10 −6 eV/c 2 with the n − n mixing strength of about 2 × 10 −5 . The picture of how the mirror-to-ordinary matter density ratio is evolved in the early universe into the observed dark-to-baryon matter density ratio of about 5.4 is presented. Reanalysis of previous data and new experiments that can be carried out under current technology are discussed and recommended to test this proposed model. Other consequences of the model on astrophysics and possible oscillations of other neutral particles are discussed as well.Free neutrons with a lifetime of about 15 minutes are known to undergo β decay via n → p + e − +ν e due to the weak force. There has been much experimental effort over the past decades for measuring the lifetime using two different techniques. The "beam" approach is to measure the neutron flux from a cold neutron beam after it going through a region where the emitted protons are detected [1,2]. It measures directly the β decay rate as far as other hidden neutron-disappearing processes are on the level of 10 −3 or below. This approach typically gives a neutron lifetime of about 888 seconds. On the other hand, the "bottle" experiments store ultracold neutrons (UCN) confined by the gravitational force in a material or magnetic trap [3,4,5]. By measuring the neutron loss rate in the trap this method typically presents a neutron lifetime of about 880 seconds. Note that any other unknown loss processes in the trap will contribute to the measured lifetime and make it appear shorter. Another different approach using a magnetic storage ring [6] provides similar results as the "bottle" method. The 1% difference between the results of the two approaches becomes more severe recently with the most precise measurements of 887.7 ± 1.2(stat) ± 1.9(sys) s ("beam") [2] and 877.7 ± 0.7(stat) + 0.4/ − 0.2(sys) s ("bottle") [3].

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confidence: 99%

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confidence: 99%

Neutron oscillations for solving neutron lifetime and dark matter puzzles

Tan

2019

Physics Letters B

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“…There have been proposals that "mirror matter", which is related to matter by the conventional P operator, may exist after all [7]. Some evidence seems to be consistent with this theory [8], but recent neutron experiments have yielded null results [9,10]. While it is impossible to completely rule out the existence of a particle with particular physical properties, the existence of such particles is not a correct prediction of the hypothesis of mirror symmetry.…”

Section: Discussionmentioning

confidence: 99%

The Mirror Symmetry of Matter and Antimatter

2010

Adv. Appl. Clifford Algebras

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Physical processes involving weak interactions have mirror images which can be mimicked in the natural universe only by exchanging matter and antimatter. This experimental observation is easily explained by the hypothesis that spatial inversion exchanges matter and antimatter. Yet according to conventional theory, the parity operator P does not exchange matter and antimatter but instead yields phenomena which have never been observed. We examine the conventional derivation of the Dirac parity operator and find that it incorrectly identifies the matrices associated with probability density (γ 0 rather than the identity matrix I) and current (γ i rather than γ 5 σi). This illusory functional dependence incorrectly requires that γ 0 preserve its sign under spatial inversion. This requirement results in a mixed-parity vector space defined relative to velocity, which is otherwise isomorphic to the spatial axes. We derive a new spatial inversion operator M (for mirroring) by introducing a pseudoscalar unit imaginary and requiring that for any set of orthogonal basis vectors, all three must have the same parity. The M operator is a symmetry of the Dirac equation. It exchanges positive and negative energy eigenfunctions, consistent with all experimental evidence of mirror symmetry between matter and antimatter. This result provides a simple reason for the apparent absence in nature of mirrorlike phenomena, such as right-handed neutrinos, which do not exchange matter and antimatter. A new time reversal operator B (for backward) is also derived to be consistent with the geometry of the polar vectors inverted by the M operator.

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“…The phenomenology of neutronmirror neutron oscillations are considered in [106][107][108][109]. Currently, there is an anomaly of 5σ (with respect to the null hypothesis) in condition of magnetic field B 0.2 Gauss in Ultra Cold Neutron (UCN) [105]. This remains to be confirmed in future experiments.…”

Section: Jhep12(2014)089mentioning

confidence: 98%

“…The limits on neutron oscillations in invisible channels are only τ n−inv > 414 s at 90% CL in suppressed magnetic field [101][102][103][104][105]. 12 So, there is no phenomenological problem with neutrons oscillating into the stable lightest neutralini or stable axini.…”

Section: Jhep12(2014)089mentioning

confidence: 99%

Neutron Majorana mass from exotic instantons

Addazi

Bianchi

2014

J. High Energ. Phys.

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We show how a Majorana mass for the neutron could result from nonperturbative quantum gravity effects peculiar to string theory. In particular, "exotic instantons" in un-oriented string compactifications with D-branes extending the (supersymmetric) standard model could indirectly produce an effective operator δm n t n + h.c.. In a specific model with an extra vector-like pair of 'quarks', acquiring a large mass proportional to the string mass scale (exponentially suppressed by a function of the string moduli fields), δm can turn out to be as low as 10 −24 -10 −25 eV.The induced neutron-antineutron oscillations could take place with a time scale τ nn > 10 8 s that could be tested by the next generation of experiments. On the other hand, proton decay and FCNC's are automatically strongly suppressed and are compatible with the current experimental limits.Depending on the number of brane intersections, the model may also lead to the generation of Majorana masses for R-handed neutrini. Our proposal could also suggest neutron-neutralino or neutron-axino oscillations, with implications in UCN, Dark Matter Direct Detection, UHECR and Neutron-Antineutron oscillations.This suggests to improve the limits on neutron-antineutron oscillations, as a possible test of string theory and quantum gravity.

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Search for neutron–mirror neutron oscillations in a laboratory experiment with ultracold neutrons

Cited by 61 publications

References 26 publications

Neutron oscillations for solving neutron lifetime and dark matter puzzles

Neutron oscillations for solving neutron lifetime and dark matter puzzles

The Mirror Symmetry of Matter and Antimatter

Neutron Majorana mass from exotic instantons

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