scholarly journals The observation of vibrating pear-shapes in radon nuclei

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
P. A. Butler ◽  
L. P. Gaffney ◽  
P. Spagnoletti ◽  
J. Konki ◽  
M. Scheck ◽  
...  

Abstract There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

2019 ◽  
Vol 223 ◽  
pp. 01007
Author(s):  
Peter Butler ◽  
Liam Gaffney ◽  
Pietro Spagnoletti ◽  
Joonas Konki ◽  
Marcus Scheck ◽  
...  

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.


2003 ◽  
Vol 18 (10) ◽  
pp. 1697-1732 ◽  
Author(s):  
SHAABAN KHALIL

We review the present status of the CP violating problem in supersymmetric extensions of the standard model. We analyze the constraints imposed by the experimental limits of the electron, neutron, and mercury electric dipole moments on the supersymmetric CP phases and show that only the scenarios with flavour-off-diagonal CP violation remain attractive. These scenarios require Hermitian Yukawa matrices which naturally arise in models with left–right symmetry or a SU(3) flavour symmetry. In this case, εK and ε′/ε can be saturated by a small non-universality of the soft scalar masses through the gluino and chargino contributions respectively. The model also predicts a strong correlation between A CP (b → sγ) and the neutron electric dipole moment. In this framework, the standard model gives a the leading contribution to the CP asymmetry in B → ψKS decay, while the dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint is set on the non-universality of this model by the recent BaBar and Belle measurements.


1993 ◽  
Vol 08 (02) ◽  
pp. 209-236 ◽  
Author(s):  
S.M. BARR

The subject of atomic and molecular electric dipole moments is reviewed from the perspective of currently interesting theories of CP violation beyond the standard model.


Author(s):  
N. J. Fitch ◽  
M. R. Tarbutt

AbstractOver the past century, the molecular beam methods pioneered by Otto Stern have advanced our knowledge and understanding of the world enormously. Stern and his colleagues used these new techniques to measure the magnetic dipole moments of fundamental particles with results that challenged the prevailing ideas in fundamental physics at that time. Similarly, recent measurements of fundamental electric dipole moments challenge our present day theories of what lies beyond the Standard Model of particle physics. Measurements of the electron’s electric dipole moment (eEDM) rely on the techniques invented by Stern and later developed by Rabi and Ramsey. We give a brief review of this historical development and the current status of eEDM measurements. These experiments, and many others, are likely to benefit from ultracold molecules produced by laser cooling. We explain how laser cooling can be applied to molecules, review recent progress in this field, and outline some eagerly anticipated applications.


2016 ◽  
Vol 31 (14n15) ◽  
pp. 1650082 ◽  
Author(s):  
Takeshi Fukuyama ◽  
Koichiro Asahi

We clarify the conditions or assumptions under which theoretical predictions of various models beyond the standard model give mainly in electric dipole moments. The correct interpretation of those conditions seems to be indispensable to the refinements of model building as well as to the mutual reliance in experimental and theoretical communities. The connections of these analyses to the recent experimental results at the LHC and the other places are also discussed.


2013 ◽  
Vol 28 (29) ◽  
pp. 1350147 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
ALEXANDER J. SILENKO

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.


2004 ◽  
Vol 19 (02) ◽  
pp. 179-204 ◽  
Author(s):  
I. HINCHLIFFE ◽  
N. KERSTING ◽  
Y. L. MA

We present a pedagogical review of particle physics models that are based on the noncommutativity of space–time, [Formula: see text], with specific attention to the phenomenology these models predict in particle experiments either in existence or under development. We summarize results obtained for high energy scattering such as would occur, for example, in a future e+e-linear collider with [Formula: see text], as well as low energy experiments such as those pertaining to elementary electric dipole moments and other CP violating observables, and finally comment on the status of phenomenological work in cosmology and extra dimensions.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pavel Fileviez Pérez ◽  
Alexis D. Plascencia

Abstract New sources of CP violation beyond the Standard Model are crucial to explain the baryon asymmetry in the Universe. We discuss the impact of new CP violating interactions in theories where a dark matter candidate is predicted by the cancellation of gauge anomalies. In these theories, the constraint on the dark matter relic density implies an upper bound on the new symmetry breaking scale from which all new states acquire their masses. We investigate in detail the predictions for electric dipole moments and show that if the relevant CP-violating phase is large, experiments such as the ACME collaboration will be able to fully probe the theory.


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