Speaker
Description
The recent CMS jet measurement provides new insights into understanding the QCD hard processes in the high-multiplicity limit (with $n>100$ tracks in jet). In this study, we aim to understand the dynamics that gives the broad multiplicity distribution $P(n)$ in the jet and the origin of the high-multiplicity tail. We start with a set of assumptions on the multiplicity distribution coming from a single parton fragmenting in the non-perturbative regime, and then, consider NLO parton splitting corrections to the multiplicity distribution. Taking a pure gluonic and exclusive jet as a toy example, we found that the NLO correction to the multiplicity distribution $P(n)$ receives a double-logarithm contribution from the collinear-soft region and a non-linear, single-logarithm enhancement from the collinear region. We propose an evolution equation that connects the multiplicity distribution from low to high energy scales. We analyze the behavior of the equation and apply it to the phenomenology of high multiplicity jets.
| Category | Theory |
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