We measure the spin-density matrix elements (SDMEs) of the Delta(++)(1232) in the photoproduction reaction gamma p -> pi(-) Delta(++)(1232) with the GlueX experiment in Hall D at Jefferson Lab. The measurement uses a linearly-polarized photon beam with energies from 8.2 to 8.8GeV and the statistical precision of the SDMEs exceeds the previous measurement by three orders of magnitude for the momentum transfer squared region below 1.4GeV(2). The data are sensitive to the previously undetermined relative sign between couplings in existing Regge-exchange models. Linear combinations of the extracted SDMEs allow for a decomposition into natural and unnatural-exchange amplitudes. We find that the unnatural exchange plays an important role in the low momentum transfer region.

There are seven species of Gyrinops and two species of Aquilaria (Thymelaeaceae), which are distributed in Eastern Indonesia at the east of the Wallace line. The anatomical character of the paradermal tissue, midrib and petiole were the important characteristics possessed by plants that can be used as data for identification. The purpose of this article was to study leaf morphoanatomical character variation of Gyrinops and Aquilaria in Indonesia Region at East Wallace Line. The Gyrinops specimen used in the research was the collection of the Agarwood Study Center, Universitas Mataram, Mataram, Indonesia. The paradermal slide was made with the whole-mount slide method and the slide cross-section of midrib and petiole was made by using a hand-free section. Their preparation process used a permanent slide method and mounted with glycerine jelly. Based on the results of the research conducted, it can be seen that the anatomical characters of paradermal tissues, midrib and petiole of Gyrinops and Aquilaria have general characteristics such as hypostomatic leaves, stomata type anomocytic, non-glandular and unicellular trichome. While other characters of structure paradermal, midrib and petiole could be used as a taxonomy diagnostic marker to identify at the level genus and species on Gyrinops and Aqilaria.

The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized 8.5 GeV photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson rho(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of s-channel helicity conservation at small squared four-momentum transfer t and are able to extract the t dependence of natural and unnatural-parity exchange contributions to the production process in detail. We confirm the dominance of natural-parity exchange over the full t range. We also find that helicity amplitudes in which the helicity of the incident photon and the photoproduced rho(770) differ by two units are negligible for -t < 0.5 GeV2/c(2).

We report the total and differential cross sections for J/& psi; photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2 GeV up to 11.44 GeV and over the full kinematic range of momentum transfer squared, t. Such coverage facilitates the extrapolation of the differential cross sections to the forward (t = 0) point beyond the physical region. The forward cross section is used by many theoretical models and plays an important role in understanding J/& psi; photoproduction and its relation to the J/& psi;-proton interaction. These measurements of J/& psi; photoproduction near threshold are also crucial inputs to theoretical models that are used to study important aspects of the gluon structure of the proton, such as the gluon generalized parton distribution of the proton, the mass radius of the proton, and the trace anomaly contribution to the proton mass. We observe possible structures in the total cross section energy dependence and find evidence for contributions beyond gluon exchange in the differential cross section close to threshold, both of which are consistent with contributions from open-charm intermediate states.

S. Adhikari, C. S. Akondi, M. Albrecht, A. Ali, M. Amaryan, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, W. K. Brooks, E. Chudakov, S. Cole, P. L. Cole, O. Cortes, V. Crede, M. M. Dalton, T. Daniels, A. Deur, S. Dobbs, A. Dolgolenko, R. Dotel, M. Dugger, R. Dzhygadlo, H. Egiyan, T. Erbora, A. Ernst, P. Eugenio, C. Fanelli, S. Fegan, ∗ J. Fitches, A. M. Foda, S. Furletov, L. Gan, H. Gao, A. Gasparian, C. Gleason, 28 K. Goetzen, V. S. Goryachev, L. Guo, M. Hagen, H. Hakobyan, A. Hamdi, J. Hernandez, N. D. Hoffman, G. Hou, G. M. Huber, A. Hurley, D. G. Ireland, M. M. Ito, I. Jaegle, N. S. Jarvis, R. T. Jones, V. Kakoyan, G. Kalicy, M. Kamel, V. Khachatryan, M. Khatchatryan, C. Kourkoumelis, S. Kuleshov, A. LaDuke, I. Larin, 14 D. Lawrence, D. I. Lersch, H. Li, W. B. Li, B. Liu, K. Livingston, G. J. Lolos, K. Luckas, V. Lyubovitskij, D. Mack, A. Mahmood, H. Marukyan, V. Matveev, M. McCaughan, M. McCracken, 29 C. A. Meyer, R. Miskimen, R. E. Mitchell, K. Mizutani, V. Neelamana, F. Nerling, L. Ng, A. I. Ostrovidov, Z. Papandreou, C. Paudel, P. Pauli, † R. Pedroni, L. Pentchev, K. J. Peters, J. Reinhold, B. G. Ritchie, J. Ritman, 15 G. Rodriguez, D. Romanov, C. Romero, K. Saldana, C. Salgado, S. Schadmand, A. M. Schertz, A. Schick, A. Schmidt, R. A. Schumacher, J. Schwiening, P. Sharp, X. Shen, M. R. Shepherd, A. Smith, E. S. Smith, D. I. Sober, A. Somov, S. Somov, O. Soto, J. R. Stevens, I. I. Strakovsky, B. Sumner, K. Suresh, V. V. Tarasov, S. Taylor, A. Teymurazyan, A. Thiel, G. Vasileiadis, T. Viducic, T. Whitlatch, N. Wickramaarachchi, M. Williams, Y. Yang, J. Zarling, Z. Zhang, Z. Zhao, J. Zhou, X. Zhou, Q. Zhou, and B. Zihlmann

We present a search for axion-like 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 − π 0 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 < m a < 480 MeV, while the search for a → π + π − π 0 decays explores the 600 < m a < 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.

The GLUEX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 mu s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GLUEX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation.

We report a measurement of the pi(-) photoproduction beam asymmetry for the reaction (gamma) over right arrowp -> pi(-)Delta(++) using data from the GLUEX experiment in the photon beam energy range 8.2-8.8 GeV. The asymmetry Sigma is measured as a function of four-momentum transfer t to the Delta(++) and compared to phenomenological models. We find that Sigma varies as a function of t : negative at smaller values and positive at higher values of vertical bar t vertical bar. The reaction can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy.

This study is part of a research collaboration between Kyoto University and The University of Mataram, aiming to identify and to utilize the agarwood plants, i.e., Gyrinops versteegii from Indonesia. The study, specifically, aims to discover anticancer agents from the bark of G. versteegii from Lombok Island of Indonesia. There were three provenances of G. versteegii observed, namely Soyun, Pantai, and Buaya. Based on the Brine Shrimp Lethality Test (BSLT), G. versteegii Buaya showed the highest cytotoxicity with LC50 45,94 µg/ml. Meanwhile, G. versteegii Soyun and Pantai have LC50 75.86 µg/mL and 56.36 µg/mL respectively. A phytochemical study showed that the methanol extract of G. versteegii Buaya containing compounds from the group of alkaloid, flavonoid, steroid, triterpenoid, and saponin. The methanol extracts fractionated using Vacuum Liquid Chromatography into 10 fractions (F1-F10) and then retested BSLT. Among the fractions, F2 showed the best potency as an anticancer with LC50 64,12 µg/mL. Based on the GC-MS analysis, the cytotoxicity from both methanol extract and F2 is predicted to be influenced by the same compounds, namely, 1,4-Benzenediol,2-methyl, Pyridoxylamine, 2,3-Dimethylhydroquionone, Tetramethyl-p-benzoquinone, and Benzofuran. Overall, the bark of G. versteegii from Lombok Island has great potency as an anticancer.

We report measurements of the photon beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ for the reaction $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}{K}^{+}{\mathrm{\ensuremath{\Sigma}}}^{0}$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2--8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ was measured as a function of the Mandelstam variable $t$, and a single value of $\mathrm{\ensuremath{\Sigma}}$ was extracted for events produced in the $u$ channel. These are the first exclusive measurements of the photon beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ for the reaction in this energy range. For the $t$ channel, the measured beam asymmetry is close to unity over the $t$ range studied, $\ensuremath{-}t=(0.1--1.4)\phantom{\rule{3.33333pt}{0ex}}$($\mathrm{GeV}/{c)}^{2}$, with an average value of $\mathrm{\ensuremath{\Sigma}}=1.00\ifmmode\pm\else\textpm\fi{}0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the ${K}^{*}$(892) Regge trajectory. A value of $\mathrm{\ensuremath{\Sigma}}=0.41\ifmmode\pm\else\textpm\fi{}\phantom{\rule{3.33333pt}{0ex}}0.09$ is obtained for the $u$ channel integrated up to $\ensuremath{-}u=2.0$ ($\mathrm{GeV}/{c)}^{2}$.

We report measurements of the photon beam asymmetry Sigma for the reaction (gamma) over right arrowp -> K+Sigma(0) (1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Sigma was measured as a function of the Mandelstam variable t, and a single value of Sigma was extracted for events produced in the u channel. These are the first exclusive measurements of the photon beam asymmetry Sigma for the reaction in this energy range. For the t channel, the measured beam asymmetry is close to unity over the t range studied, -t = (0 .1-1 .4) (GeV/c)(2) , with an average value of Sigma = 1 .00 +/- 0 .05. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K*(892) Regge trajectory. A value of Sigma = 0 .41 +/- 0 .09 is obtained for the u channel integrated up to -u = 2 .0 (GeV/c)(2).

We report measurements of the photon beam asymmetry Σ for the reaction γ⃗ p→ K^+Σ^0(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Σ was measured as a function of the Mandelstam variable t, and a single value of Σ was extracted for events produced in the u-channel. These are the first exclusive measurements of the photon beam asymmetry Σ for the reaction in this energy range. For the t-channel, the measured beam asymmetry is close to unity over the t-range studied, -t=(0.1-1.4)(GeV/c)^2, with an average value of Σ = 1.00± 0.05. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K^*(892) Regge trajectory. A value of Σ = 0.41 ± 0.09 is obtained for the u-channel integrated up to -u=2.0 (GeV/c)^2.

We report on the measurement of the beam asymmetry Sigma for the reactions (gamma) over right arrowp -> p eta and (gamma) over right arrowp -> p eta' from the GlueX experiment using an 8.2-8.8-GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Laboratory. These measurements are made as a function of momentum transfer -t with significantly higher statistical precision than our earlier. measurements and are the first measurements of eta' in this energy range. We compare the results to theoretical predictions based on t-channel quasiparticle exchange. We also compare the ratio of Sigma(eta) to Sigma(eta)' to these models as this ratio is predicted to be sensitive to the amount of s (s) over bar exchange in the production. We find that photoproduction of both eta and eta' is dominated by natural parity exchange with little dependence on -t.

A. Ali, M. Amaryan, E. G. Anassontzis, A. Austregesilo, M. Baalouch, F. Barbosa, J. Barlow, A. Barnes, E. Barriga, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, M. Boer, W. J. Briscoe, T. Britton, W. K. Brooks, B. E. Cannon, N. Cao, E. Chudakov, S. Cole, O. Cortes, V. Crede, M. M. Dalton, T. Daniels, A. Deur, S. Dobbs, A. Dolgolenko, R. Dotel, M. Dugger, R. Dzhygadlo, H. Egiyan, A. Ernst, P. Eugenio, C. Fanelli, S. Fegan, A. M. Foda, J. Foote, J. Frye, S. Furletov, L. Gan, A. Gasparian, V. Gauzshtein, 26 N. Gevorgyan, C. Gleason, K. Goetzen, A. Goncalves, V. S. Goryachev, L. Guo, H. Hakobyan, A. Hamdi, S. Han, J. Hardin, G. M. Huber, A. Hurley, D. G. Ireland, M. M. Ito, N. S. Jarvis, R. T. Jones, V. Kakoyan, G. Kalicy, M. Kamel, C. Kourkoumeli, S. Kuleshov, I. Kuznetsov, 26 I. Larin, D. Lawrence, D. I. Lersch, H. Li, W. Li, B. Liu, K. Livingston, G. J. Lolos, V. Lyubovitskij, 26 D. Mack, H. Marukyan, V. Matveev, M. McCaughan, M. McCracken, W. McGinley, J. McIntyre, C. A. Meyer, R. Miskimen, R. E. Mitchell, F. Mokaya, F. Nerling, L. Ng, A. I. Ostrovidov, Z. Papandreou, M. Patsyuk, P. Pauli, R. Pedroni, L. Pentchev, K. J. Peters, W. Phelps, E. Pooser, N. Qin, J. Reinhold, B. G. Ritchie, L. Robison, D. Romanov, C. Romero, C. Salgado, A. M. Schertz, R. A. Schumacher, J. Schwiening, K. K. Seth, X. Shen, M. R. Shepherd, E. S. Smith, D. I. Sober, A. Somov, S. Somov, O. Soto, J. R. Stevens, I. I. Strakovsky, V. Tarasov, S. Taylor, A. Teymurazyan, A. Thiel, G. Vasileiadis, D. Werthmüller, T. Whitlatch, N. Wickramaarachchi, M. Williams, T. Xiao, Y. Yang, J. Zarling, Z. Zhang, G. Zhao, Q. Zhou, X. Zhou, and B. Zihlmann

This proposal presents our plan to make a precision measurement of the cross section for γγ → π0π0 via the Primakoff effect using the GlueX detector in Hall D. The aim is to significantly improve the data in the low π0π0 invariant mass domain, which is essential for understanding the low energy regime of Compton scattering on the π0. In particular, the aim is to obtain a first accurate experimental determination of the neutral pion polarizability απ − βπ, which is one of the important predictions of chiral perturbation theory and a key test of chiral dynamics on the π0. Our goal is to measure σ(γγ → π0π0) to a precision of ∼1%, which would determine the combination of απ0−βπ0 to a precision of 10%. We expect this experiment to run concurrently with the previously approved experiment to measure the charged pion polarizability (CPP) [1] in Hall D.

Eaglewood (Gyrinops verstiigee) is one example of a commercially valuable aromatic plant in the form of agarwood. The high selling value of agarwood encourages people to use it. The distribution area of Agarwood-producing trees is found in several regions in Indonesia. One of agarwood producers has been widely exploited in West Nusa Tenggara Province. The problem is the number of population and the quality of agarwood production which is declining due to exploitation carried out continuously and excessively without calculations and improper harvesting techniques. Therefore, a forest management model that cares for sustainability, called a sustainable harvesting model, could be used. This research used harvesting matrix to build this model. This model considers the initial configuration of the forest to be the same as the final configuration of the forest, so that the harvesting could be done continuously without damaging the forest configuration. The location of data collection was conducted in several areas, such as Orong Puncak, Lembah Sari, Orong Selatan, Kekait, Sepakek, East Lombok, and Kerujuk. The data obtained were divided into 5 intervals based on the diameter of the eaglewood tree. The research found that the number of trees that could be harvested on one harvesting period at each interval of trees diameter, i.e. 0 tree in 0-10 cm interval; 388 trees in 10-20 cm interval; 270 trees in 20-30 cm interval; 17 trees in 30-40 cm interval; and 3 trees in 40-50 cm interval. Harvesting matrix could be used to help the government in order to build a strategy for the sustainability of eaglewood trees in Lombok Island.

The design, simulation, fabrication, calibration, and performance of the GLUEX Start Counter detector are described. The Start Counter was designed to operate at integrated rates of up to 9 MHz with a timing resolution in the range of 500 to 825 ps (FWHM). The Start Counter provides excellent solid angle coverage, a high degree of segmentation for background rejection, and can be utilized in the level 1 trigger for the experiment. It consists of a cylindrical array of 30 thin scintillators with pointed ends that bend towards the beam line at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were used as the light sensors.

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