Measurement of the Photoproduction Cross-Section of\u3ci\u3e f\u3c/i\u3e\u3csub\u3e1\u3c/sub\u3e(1285) in the Exclusive Reactions \u3ci\u3eγp\u3c/i\u3e → \u3ci\u3ep′K\u3c/i\u3e\u3csup\u3e∓\u3c/sup\u3eK\u3csub\u3eS\u3c/sub\u3eπ\u3csup\u3e±\u3c/sup\u3e at 7.5 \u3c \u3ci\u3eEγ\u3c/i\u3e \u3c 11.5 GeV With GlueX at Jefferson Lab

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 \u3c Eγ \u3c 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

Measurement of Spin Density Matrix Elements in Λ(1520) Photoproduction at 8.2-8.8 GeV

We report on the measurement of spin density matrix elements of the Λ(1520) in the photoproduction reaction γp→Λ(1520)K+, via its subsequent decay to K−p. The measurement was performed as part of the GlueX experimental program in Hall D at Jefferson Laboratory using a linearly polarized photon beam with Eγ = 8.2 GeV–8.8 GeV. These are the first such measurements in this photon energy range. Results are presented in bins of momentum transfer squared, − (t − t0). We compare the results with a Reggeon exchange model and determine that natural exchange amplitudes are dominant in Λ(1520) photoproduction

Search for Photoproduction of Axionlike Particles at GlueX

We present a search for axionlike particles, a, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the a-gluon coupling is dominant. The search uses a → γγ and a → π+π−π0 decays, and a data sample corresponding to an integrated luminosity of 168  pb−1 collected with the GlueX detector. The search for a → γγ decays is performed in the mass range of 180 \u3c ma \u3c480  MeV, while the search for a → π+π−π0 decays explores the 600 \u3c ma \u3c 720  MeV region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the a-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered