CCharge-multiplicity dependence of single-particle transverse-rapidity $\bf y_t$ and pseudorapidity $\bf \eta$ densities and 2D angular correlations from 200 GeV $p$-$p$ collisions

TL;DR

This paper analyzes how charge multiplicity affects single-particle densities and angular correlations in 200 GeV proton-proton collisions, providing a comprehensive model that includes a nonjet quadrupole component and implications for collectivity and flow phenomena.

Contribution

It introduces a self-consistent two-component model for hadron production in $p$-$p$ collisions, revealing a significant nonjet quadrupole component and exploring its implications for small-system collectivity.

Findings

Identification of a significant nonjet quadrupole component in $p$-$p$ collisions.

Charge-multiplicity dependence of 2D angular correlations and single-particle densities.

Implications for $p$-$p$ centrality, underlying event, and collectivity in small systems.

Abstract

An established phenomenology and theoretical interpretation of $p$-$p$ collision data at lower collision energies should provide a reference for $p$-$p$ and other collision systems at higher energies, against which claims of novel physics may be tested. The description of $p$-$p$ collisions at the relativistic heavy ion collider (RHIC) has remained incomplete even as claims for collectivity and other novelties in data from smaller systems at the large hadron collider (LHC) have emerged recently. In this study we report the charge-multiplicity dependence of two-dimensional (2D) angular correlations and of single-particle (SP) densities on transverse rapidity $y_t$ and pseudorapidity $\eta$ from 200 GeV $p$-$p$ collisions. We define a comprehensive and self-consistent two-component (soft + hard) model (TCM) for hadron production and report a significant $p$-$p$ nonjet (NJ) quadrupole component as a third (angular-correlation) component. Our results have implications for $p$-$p$ centrality, the underlying event (UE), collectivity in small systems and the existence of flows in high-energy nuclear collisions.