Date of Award

Summer 2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Program/Concentration

Physics

Committee Director

Moskov Amaryan

Committee Member

Alexander Gurevich

Committee Member

Anatoly Radyushkin

Committee Member

Lawrence Weinstein

Committee Member

Richard Zimmerman

Abstract

The f1(1285) meson is commonly understood to belong to the axial-vector nonet as the low-mass isoscalar partner to the f1(1420) but has been suggested as a candidate for a KK∗+c.c molecule. A nearly mass-degenerate 0 −+ state has been observed in πp scattering that calls into question the established branching ratios of the f1(1285) decays. Recently, the differential cross-section for the photoproduction of f1(1285) was measured by the CLAS experiment and the results disagreed with theoretical predictions. Additionally, the CLAS experiment did not observe a mass-degenerate 0−+ state. We present the results of the first photoproduction cross-section measurement dσ/dt of f1(1285) at 7.5 < Eγ < 11.5 GeV from the GlueX experiment at Thomas Jefferson National Accelerator Facility in the reactions γp → p′K −Ksπ+ and γp → p′K +Ksπ −. We find that the production mechanism of f1(1285) is consistent with t-channel exchange. We also observe a difference in the differential cross-section of f1(1285) as a function of −t as measured in the charge conjugated K∓Ksπ± decay modes that we hypothesize to be due to baryonic N∗ interference. The observed distributions of M(KK) and M(Kπ) are consistent with both a qq¯ state and predictions for a KK∗ +c.c molecular state. Additionally, we find that the cross-section at low M(KKπ) is dominated by the 1++ state.

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DOI

10.25777/6hk9-eh38

ISBN

9798384455066

ORCID

0009-0003-5562-6465

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