Photoproduction of phi(1020) mesons on the proton at large momentum transfer

Electroproduction of exclusive $\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.4\leq Q^2\leq 3.8$ GeV$^{2}$, $0.0\leq t^{\prime}\leq 3.6$ GeV$^{2}$, and $2.0\leq W\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\phi}^2)^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\phi}=0.98 \pm 0.17$ GeV$^{-2}$. Under the assumption of s-channel helicity conser...

The differential cross section, $d\sigma/dt$, for $\rho^0$ meson photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The $\rho^0$ channel was extracted from the measured two charged-pion cross section by fitting the $\pi^+\pi^-$ and $p\pi^+$ invariant masses. The low momentum transfer region shows the typical diffractive...

The differential cross section, $d\sigma/dt$ for $\omega$ meson exclusive photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at Jefferson Laboratory. The $\omega$ channel was identified by detecting a proton and $\pi^+$ in the final state and using the missing mass technique. While the low momentum transfer region shows the typical diffractive pattern expected from Pomeron ...

The cross section and decay angular distributions for the coherent \phi meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t =(p_{\gamma}-p_{\phi})^2 =-2 GeV^2/c^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a re-scattering model. In a framework of vector meson dominance, the data are consistent with the total \phi-N cross s...

The exclusive reaction $\gamma p \to p K^+ K^-$ was studied in the photon energy range $3.0 - 3.8 \mbox{ GeV}$ and momentum transfer range $0.6<-t<1.3 \mbox{ GeV}^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was approximately 20 pb$^{-1}$. The reaction was isolated by detecting the $K^+$ and the proton in CLAS, and reconstructing the $K^-$ via the missing-mass technique....

Differential cross sections at $t=t_{\text{min}}$ and decay asymmetries for the $\gamma p\rightarrow\phi p$ reaction have been measured using linearly polarized photons in the range 1.5 to 2.9 GeV. These cross sections were used to determine the Pomeron strength factor. The cross sections and decay asymmetries are consistently described by the $t$-channel Pomeron and pseudoscalar exchange model in the $E_{\gamma}$ region above 2.37 GeV. In the lower energy region, an excess o...

We present the first measurement of the exclusive reaction $\gamma p \rightarrow a_2(1320)^0 \, p$ in the photon energy range $3.5$-$5.5$ GeV and four-momentum transfer squared $0.2<-t<2.0$ GeV$^2$. Data were collected with the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility. The neutral $a_2$ resonance was detected by measuring the reaction $\gamma p \rightarrow \pi^0 \eta p$ and reconstructing the $\pi^0 \eta$ invariant mass. The di...

We report on the first measurement of the differential cross section of $\phi$-meson photoproduction for the $d(\gamma,pK^{+}K^{-})n$ exclusive reaction channel. The experiment was performed using a \textcolor{black}{tagged-photon} beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the $d(\gamma,pK^{+}K^{-})n$ channel and those from a previous publication on coherent $\phi$ production on the deuteron has been carried ...

We studied the exclusive reaction e p --> e' p' phi using the phi --> K^+ K^- decay mode. The data were collected using a 4.2 GeV incident electron beam and the CLAS detector at Jefferson Lab. Our experiment covers the range in Q^2 from 0.7 to 2.2 GeV^2, and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of phi production on the proton. Our measurement shows the expected decrease of the t-slope with the vector meson formation time c...

We comment on the important phenomenological aspects of the recent high-statistics and wide-angle coverage $\phi$ photoproduction data from CLAS at Jefferson Lab. The most prominent feature is a localized structure at a center-of-mass (c.m) energy $\sqrt{s} \sim 2.2$ GeV that is not expected in a simple $t$-channel Pomeron-exchange model. The structure exists only at the forward production angles that almost rules out any resonance contribution. Strong rescattering effects be...