Götzen, K.GSI*

2024

Abstract: Summary. — The new Facility for Antiproton and Ion Research (FAIR) is un-der construction at GSI in Darmstadt (Germany). Antiprotons are planned to beprovided by the High Energy Storage Ring, where the PANDA experiment will di-rectly be located. It represents the central part of the hadron physics programme.The field of hadron spectroscopy has gained new momentum by the discovery ofthe so-called charmonium-like and bottomonium-like exotic states over the past twodecades. The nature of many of the so-called exotic XY Z states in the charmoniumregion are, however, not yet understood. Precise measurements of hadron massesand widths are mandatory to sort out different theoretical models and clarify thenature of these unexpected states. One example is the χc1(3872), formerly knownas X(3872) —although being the first of the new charmonium-like states discoveredsince 2003, the nature of this state is still not clarified. In p¯p annihilation, such XY Zstates can be produced in direct formation, allowing for a precise resonance energyscan. Using the example of the X(3872), we quantified the expected sensitivity ofenergy scans of narrow resonances and how well we can distinguish between modelsthat turn out to be indistinguishable from the LHCb data.

1. ( FAIR Facility )