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arXiv · 1804.00375

Threshold Effects and the Line Shape of the X(3872) in Effective Field Theory

M. Schmidt·M. Jansen·H. -W. Hammer
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Abstract

Latest measurements suggest that the X(3872) mass lies less than 200 keV away from the D0-Dbar0* threshold, reenforcing its interpretation as a loosely-bound mesonic molecule. This observation implies that in processes like D0-Dbar0-pi0 production, threshold effects could disguise the actual pole position of the X(3872). We propose a new effective field theory with D0, Dbar0 and pi0 degrees of freedom for the X(3872), considering Galilean invariance to be an exact symmetry. The D0* enters as a D0-pi0 p-wave resonance, allowing for a comprehensive study of the influence of pion interactions on the X(3872) width. We calculate relations between the mass of the X(3872), its width, and its line shape in D0-Dbar0-pi0 production up to next-to-leading order. Our results provide a tool for the extraction of the X(3872) pole position from the experimental data near threshold.

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M. Schmidt, M. Jansen, H. -W. Hammer. 2018-04-02. Threshold Effects and the Line Shape of the X(3872) in Effective Field Theory. https://doi.org/10.1103/physrevd.98.014032

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