Beyond axion discovery: distinguishing different axion models and further searches with (Baby)IAXO

• Daniel Heuchel (DESY)

Room: SR 4 As the next generation axion helioscope, the International Axion Observatory (IAXO) will search for solar axions and axion-like particles (ALPs) with unprecedented sensitivities. Its intermediate experimental stage, BabyIAXO, is proposed to be sited at HERA hall south at DESY. BabyIAXO aims to convert those particles into X-rays via the Sikivie effect in a strong magnet pointing towards the sun. This is followed by high-precision focusing and ultra-low background and high-efficiency X-ray detectors. Along with a 10 m long and about 2-3 T strong superconducting magnet, hosting two 70 cm diameter bores, optics and detector systems very similar to the ones foreseen for IAXO will complete the two detection lines. However, BabyIAXO will not only serve as a prototype-stage for all IAXO subsystems, but it will be a fully fledged helioscope with potential for discovery. In contrast to other experimental axion searches, helioscopes like BabyIAXO have the unique possibility to go beyond potential discovery and probe different axion couplings. This ability provides crucial information on the nature of the underlying model. After a brief introduction to the general concept of axion helioscopes and (BabyI)AXO, this seminar talk will focus on the (Baby)IAXO science case post axion discovery and related ongoing studies. This includes the probing of the axion-electron and axion-nucleon coupling and the idea to measure the X-ray polarisation with dedicated and optimised detection systems. Lastly, haloscope approaches and the search for high frequency gravitational waves, turning (Baby)IAXO into a multi-purpose facility similar to ALPS II, will be discussed briefly.

Pizza Room: SR 4