Improved Determination of the Neutron Lifetime

Yue, Andrew; Dewey, M. S.; Gilliam, David M.; Greene, Geoffrey L.; Laptev, A.; Nico, J. S.; Snow, W. M.; Wietfeldt, F. E.

doi:10.1103/physrevlett.111.222501

Cited by 252 publications

(232 citation statements)

References 20 publications

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“…± 1.9(syst.)] s (68% CL) [37], that lead to an additional theoretical uncertainty in Y p (O(0.6%)) and y DP (O(0.4%)) 8 . For non-zero chemical potentials this uncertainty can increase to maximally O(1%), i.e.…”

mentioning

confidence: 99%

Improved constraints on lepton asymmetry from the cosmic microwave background

Oldengott¹,

Schwarz²

2017

EPL

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-A cosmic lepton asymmetry η l = (n l − nl)/nγ affects the primordial helium abundance and the expansion rate of the early Universe. Both of these effects have an impact on the anisotropies of the cosmic microwave background (CMB). We derive constraints on the neutrino chemical potentials from the Planck 2015 data, assuming equal lepton flavour asymmetries and negligible neutrino masses. We find ξ = −0.002−0.111 (95% CL) for the chemical potentials, which corresponds to −0.085 ≤ η l ≤ 0.084. Our constraints on the lepton asymmetry are significantly stronger than previous constraints from CMB data analysis and we argue that they are more robust than those from primordial light element abundances. The resulting constraints on the primordial helium and deuterium abundances are consistent with those from direct measurements.

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confidence: 99%

Improved constraints on lepton asymmetry from the cosmic microwave background

Oldengott¹,

Schwarz²

2017

EPL

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“…Its 1 s uncertainty is far greater than the 0.1 s sensitivity required for new physics searches, and is dominated by the ∼ 8 s discrepancy between the two methods. Although earlier experiments have been reanalyzed [73,74,75] since the present best resulted τ n = 878.5(8) s [76], the discrepancy could not yet be resolved. We note that the most precise 'magnetic storage' experiment [77] is not included in the PDG average.…”

Section: The Neutron Lifetime Puzzlementioning

confidence: 85%

Cold and Ultra-cold Neutrons as Probes of New Physics

Konrad¹,

Abele²

2017

Proceedings of the 26th International Nuclear Physics Conference — PoS(INPC2016)

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Despite the great success of the Standard Model, many key questions in particle physics, astrophysics, and cosmology are unanswered. In particular, more than 95 % of the universe consists of unknown dark matter and dark energy. Today, a major goal of particle physics is to look for evidence of new physics beyond the Standard Model. Collider searches for new physics are well suited to the direct production of new high-mass particles, whereas low-energy precision experiments search for traces that new particles leave in known processes. Direct and indirect evidence of new physics are highly complementary. High-precision experiments with extremely slow, cold and ultra-cold neutrons address some of the unanswered questions, for instance, on the nature of the fundamental forces and underlying symmetries, the origin, evolution, and fate of the universe, or on the nature of the gravitational force at very small distances. For example, the limit on the electric dipole moment of the neutron constrains the CP violating phases, the lifetime of the neutron determines the relative helium abundance in the universe, and neutrons bouncing over a mirror probe dark matter and dark energy. New facilities and technological developments now give window for significant improvement in precision by one to two orders of magnitude. In this paper, we will give an overview of current and planned facilities and experiments, as well as an overview of some of the applications of neutrons to astrophysics, cosmology, and physics beyond the Standard Model.

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“…6) Relations (23), (24) and (25) clearly demonstrate the combined role of (G s , G e ) in understanding the Avogadro number, molar mass constant and atomic radii. 7) Relations (26) to (34) seem to extend the scope of applicability of the proposed assumptions in astrophysics starting from neutron stars to galactic nuclei.…”

Section: Discussionmentioning

confidence: 99%

“…With 1-2 % error, this obtained value can be compared with recommended [13] and experimental [24,25] neutron life times of   878 to 888 sec . With reference to weak coupling constant and proposed gravitational constant associated with strong interaction,…”

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confidence: 99%

Towards a workable model of final unification

Seshavatharam¹,

I-Serve

Lakshminarayana

2016

INT J MATH PHYS

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Even though 'String theory' models and "quantum gravity' models are having a strong mathematical back ground and sound physical basis, they are failing in implementing the Newtonian gravitational constant in atomic and nuclear physics and thus seem to fail in developing a 'workable' model of final unification. In this context, extending Abdus Salam's old concept of 'nuclear strong gravitational coupling' we consider two very large pseudo gravitational constants assumed to be associated with electromagnetic and strong interactions. By combining the two microscopic pseudo gravitational constants with the Newtonian gravitational constant, we make an attempt to combine the old 'strong gravity' concept with 'Newtonian gravity' and try to understand and re-interpret the constructional features of nuclei, atoms and neutron stars in a unified approach. Finally we make a heuristic attempt to estimate the Newtonian gravitational constant from the known elementary atomic and nuclear physical constants. By exploring the possibility of incorporating the proposed two pseudo microscopic gravitational constants in current unified models, in near future, complete back ground physics can be understood and observable low energy predictions can be made.

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Improved Determination of the Neutron Lifetime

Cited by 252 publications

References 20 publications

Improved constraints on lepton asymmetry from the cosmic microwave background

Improved constraints on lepton asymmetry from the cosmic microwave background

Cold and Ultra-cold Neutrons as Probes of New Physics

Towards a workable model of final unification

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