Why are we living in a world of matter? What is the reason for the large matter–antimatter asymmetry observed in the Universe? The MORA (Matter’s Origin from the RadioActivity of trapped and oriented ions ) project aims at searching for possible hints in nuclear beta decays, through the measurement of the so-called D correlation. <br />: P. Delahaye et al., arXiv:1812.02970, proceedings of the TCP 2018 conference, Hyp. Int.(2019)240:63.
The D correlation in the spectrum of nuclear beta decay offers the possibility to search for new CP-violating interactions in a region that is less accessible by EDM searches, in particular via the Leptoquark model. <br />With a sensitivity on D close to 10-5, the MORA apparatus will additionally permit to probe the FSI (Final State Interactions) effects for the first time. <br />Such a challenging measurement requires: <br />* the preparation of an intense source of beta-decaying polarized nuclei <br />* the efficient detection of the recoiling ions in coincidence with the betas <br />* a good control and reduction of all potential systematic effects <br />On the theoretical side, the sensitivity to different models of New Physics of such a measurement has to be compared to constraints from other observables ongoing measurements (nEDM, exotic pion decay channels).
Technically, MORA uses an innovative in-trap orientation method, which combines the high trapping efficiency of a transparent Paul trap with laser orientation techniques. Recent studies have shown that a polarization degree close to 100% could be obtained with 23Mg+ ions in the trap after a few pulses of a laser system based on Ti:Sa cavities. The transparent Paul trap and beam optics have been designed with numerical methods to optimize the trap performances while maintaining large solid angles for the detection of the charged particles emitted during the decay. The tests of the detection setup have been done at GANIL and LPC Caen. The MORA apparatus will be first commissioned in the IGISOL beam lines at JYFL where the laser system is readily available, before moving back to GANIL where its nominal sensitivity to New Physics will eventually be obtained with the intense beams of SPIRAL 1.
On the theoretical side, Effective Field Theories (EFT's) will be used to investigate the sensitivity of the 10-5 D correlation to different Leptoquark models. It will be compared to present and future constraints from other observables. EFT's will also be used to revisit the calculation of FSI effects which mimic a non zero D correlation below 10-4.
The expected experimental results are:
* the proof of principle of the in-trap laser polarization technique
* the first measurement of the D correlation to the 10-4 level in JYFL
* a classification of popular New Physics Models to which the D corrrelation measurement to a level of 10-5 is sensitive
* the revisit of the FSI effects calculations in nuclear beta decay
* The in-trap laser polarization method is innovative and has never been demonstrated before. As such, it would bring new opportunities for eg other correlation measurements in nuclear beta decay.
* The first measurement of D to the 10-4 level will already explore some unknown territory. The best measurement so far of the D correlation is the one done by the emiT collaboration: D< 2.10-4. Below this value the measurement starts to be sensitive to any overlooked boson that could possibly having been missed by other measurements, and not taken into account in the present EFT framework. This possibility is not excluded, considering the many speculations which are made on the existence of a light boson to explain the present deviation from SM of the muon g-2 anomaly.
* The theoretical studies will lead to a classification of popular New Physics models to which a measurement of D at level of 10-5 is sensitive
* The theoretical studies will provide a new estimate of the FSI effects and of their precision, the calculations of which were made in the 1970s. A correct knowledge of the precision is essential for enabling the research of New Physics via a D measurement to the 10-5 level.
* Delahaye, P., Liénard, E., Moore, I. et al., The MORA project, Hyperfine Interact (2019) 240: 63. doi.org/10.1007/s10751-019-1611-x
* Delahaye, P., Analytical model of an ion cloud cooled by collisions, Eur. Phys. J. A (2019) 55: 83. doi.org/10.1140/epja/i2019-12740-4
* Delahaye, P., Ban, G., Benali, M. et al., The open LPC trap for precision measurements in beta decay, Eur. Phys. J. A (2019) 55: 101. doi.org/10.1140/epja/i2019-12777-3
* Benali M., Quemener G., Delahaye P. et al, Geometry optimisation of a transparent axisymmetric ion trap for the MORA project, Eur. Phys. J. A (2020) 56: 163, doi.org/10.1140/epja/s10050-020-00168-y
* A. Falkowski, M. Gonzalez Alonso and O. Naviliat Cuncic, Comprehensive analysis of beta decays within and beyond the Standard Model, arXiv:2010.13797 [hep-ph]
The MORA (Matter's Origin from the RadioActivity of trapped and laser oriented ions)  project gathers experts of ion manipulation in traps and laser orientation methods for searches of New Physics (NP) in nuclear beta decay. These searches are done via the precise measurement of the so-called triple D correlation, which is sensitive to Time reversal violation, and via the CPT theorem, to CP violation. As such, the parameter D measured in nuclear beta decay is a complementary probe to the electric dipole moment of the neutron. A large CP violation is needed to explain the matter – antimatter asymmetry observed in the Universe. The D correlation is particularly sensitive to the existence of Leptoquarks, which are hypothetical gauge bosons appearing in the first theories of baryogenesis. Leptoquarks are now actively searched for at the LHC, the measurements at which provide competitive and complementary constraints.
The MORA project was recently funded by Region Normandie. The grant focused on the equipment required by MORA. In the present project, the MORA collaboration applies for an additional support from ANR to achieve the proof of principle experiments at JYFL before the final experiments are carried out at GANIL. This support consists in the fundings of postdocs and PhD in experimental and theoretical physics, as well as additional support for installation at JYFL, which has not been covered in the initial support from Region Normandie.
: The MORA project, P. Delahaye et al., arXiv:1812.02970 [physics.ins-det], TCP 2018, proceedings to appear in Hyp. Int.
Monsieur Pierre Delahaye (Grand accélérateur national d'ions lourds)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
GANIL Grand accélérateur national d'ions lourds
LPC Caen LABORATOIRE DE PHYSIQUE CORPUSCULAIRE DE CAEN
LPT Laboratoire de physique théorique
University of Jyväskylä / JYFL
CERN / ISOLDE
IKS KU Leuven / IKS
School of Physics and Astronomy / The University of Manchester
IFIC Valencia Instituto de Física Corpuscular
Help of the ANR 438,639 euros
Beginning and duration of the scientific project: December 2019 - 48 Months