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arXiv · 2409.16067

Evidence of collinear factorization breaking due to collinear-to-soft Glauber exchanges for a $2 \to 3$ exclusive process at leading twist

Saad Nabeebaccus·Jakob Schoenleber·Lech Szymanowski·Samuel Wallon
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Abstract

We exhibit an exclusive process, namely the photoproduction of a $\pi^{0}\gamma$ pair with large invariant mass, which violates collinear factorization. We explicitly demonstrate that this is due to the fact that there exists diagrams with gluon exchange in $t$ channel, contributing at the leading power, for which Glauber gluons are trapped. This is caused by the pinching of the contour integration of both the plus and minus light-cone components of the Glauber gluon momentum. We argue that this leads to the observed ``endpoint-like'' divergence of the convolution integral at leading order and leading power when collinear factorization is na\"ively assumed.

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Saad Nabeebaccus, Jakob Schoenleber, Lech Szymanowski, Samuel Wallon. 2024-09-24. Evidence of collinear factorization breaking due to collinear-to-soft Glauber exchanges for a $2 \to 3$ exclusive process at leading twist. https://arxiv.org/abs/2409.16067

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