124596955
Hadron Dynamics with Vector Mesons: Matching Theory and Experiment to Identify New Resonances
In this paper, we discuss the γp → KΣ and γn → KΣ reactions, with a peculiar behavior around the K∗0Λ threshold, due to a 1/2− resonance around 2035 MeV. Similarly, we discuss a BES experiment, J/ψ → ηK∗0K̄∗0 decay, which supports the existence of a new h1 resonance around 1830 MeV that was predicted from the vector–vector interaction. A short discussion is then made about recent advances in the charm and beauty sectors.
118784454
Interaction of vector mesons with baryons and vectors in the nuclear medium
In this talk we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei. We begin with the hidden gauge formalism for the interaction of vector mesons, then review results for vector baryon interaction and in particular the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons. New developments concerning the mixing of these states with pseudoscalars and baryons are also reported. We include some discussion on the $5/2^+$ $\Delta$ resonances around 2000 MeV, where we suggest that the $\Delta(2000)5/2^+$ resonance, which comes in the PDG from averaging a set of resonances appearing around 1700 MeV and another one around 2200 MeV, corresponds indeed to two distinct resonances. We also report on a hidden charm baryon state around 4400 MeV coming from the interaction of vector mesons and baryons with charm, and how this state has some repercussion in the $J/\psi$ suppression in nuclei. The interaction of $K^*$ in nuclei is also reported and suggestions are made to measure by means of the transparency ratio the huge width in the medium that the theoretical calculations predict. The formalism is extended to $J/\psi$ interaction with nuclei and the transparency ratio for $J/\psi$ photoproduction in nuclei is studied and shown to be a good tool to find possible baryon states which couple to $J/\psi N$.
118870069
$\bar{B}^0$ and $\bar{B}^0_s$ decays into $J/\psi$ and $f_0(1370),~f_0(1710),~f_2(1270),~f'_2(1525),~K^*_2(1430)$
We make predictions for the ratios of branching fractions of ${\bar B}^0$ and ${\bar B}^0_s$ decays into $J/\psi$ and the scalar mesons $f_0(1370),~f_0(1710)$ or tensor mesons $f_2(1270),~f'_2(1525),~K^*_2(1430)$. The theoretical approach is based on results of chiral unitary theory where these resonances are shown to be generated from the vector meson-vector meson interaction. Eight independent ratios can be predicted and comparison is made with the recent data on $\bar{B}^0_s$ decay into $J/\psi f'_2(1525)$ versus the $\bar{B}^0_s$ decay into $J/\psi f_2(1270)$.
62797135
Faddeev fixed center approximation to the $N\bar{K}K$ system and the signature of a $N^*(1920)(1/2^+)$ state
We perform a calculation for the three-body NK-barK scattering amplitude by using the fixed-center approximation to the Faddeev equations, taking the interaction between N and K-bar, N and K, and K-bar and K from the chiral unitary approach. The resonant structures show up in the modulus squared of the three-body scattering amplitude and suggest that a NK-barK hadron state can be formed. Our results are in agreement with others obtained in previous theoretical works, which claim a new N* resonance around 1920 MeV with spin-parity J{sup P}=1/2{sup +}. The existence of these previous works allows us to test the accuracy of the fixed center approximation in the present problem and sets the grounds for possible application in similar problems, as an explorative tool to determine bound or quasibound three-hadron systems.
118425223
Are there three Xi(1950) states
Different experiments on hadron spectroscopy have long suspected the existence of several cascade states in the $1900-2000 {\rm MeV}$ region. They are usually labeled under the common name of $\Xi (1950)$. As we argue here, there are also theoretical reasons supporting the idea of several $\Xi (1950)$ resonances. In particular, we propose the existence of three $\Xi(1950)$ states: one of these states would be part of a spin-parity $(1/2)^{-}$ decuplet and the other two probably would belong to the $(5/2)^{+}$ and $(5/2)^{-}$ octets. We also identify which decay channels are the more appropriate for the detection of each of the previous states.
119299782
Evidence of N-*(1535) resonance contribution in the pn -> d phi reaction
The N-*(1535) resonance contributions to the pn -> d phi reaction are evaluated in an effective Lagrangian model. The pi-, eta-, and rho-meson exchange are considered. It is shown that the contributions from pi- and rho-meson exchange are dominant, while the contribution from eta-meson exchange is negligibly small. Our theoretical results reproduce the experimental data of both total cross section and angular distribution well. This is more evidence that the N-*(1535) resonance has a large ss component leading to a large coupling to N phi, which may be the real origin of the Okubo-Zweig-Iizuka rule violation in the pi N and pN reactions.
4567819
Influence of Growth Method on K3Sb Photocathode Structure and Performance
A combination of material science techniques is used to determine the influence of the growth parameters on structure and performance of photocathode materials. In-situ x-ray diffraction (XRD) and in-situ grazing incidence small angle x-ray scattering (GiSAXS), as well as after growth xray reflectivity (XRR) and�/2� - XRD measurements were performed at synchrotron radiation sources. K3Sb is a precursor material for the preparation of CsK2Sb and Na2KSb. The materials growth was studied intensively to optimize this intermediate growth step in terms of quantum efficiency and roughness. The results of two growth methods, a “layer by layer” type and a “super-lattice type”, are presented, as well as the interaction of the K3Sb phase with Cesium.
3112937
Free electron laser research in China
China has endeavored in the field of FEL research since the mid-eighties. Compton regime, Raman regime, electromagnetic pumping, Cherenkov FEL, and harmonic generator FEL, etc. based on the RF linac accelerator, induction linac accelerator, pulsed-line accelerator, and storage ring have all been developed. These experimental projects are in various stages of development and are discussed in sequence. Theoretical analysis, numerical simulation and components research related to an FEL also will be mentioned briefly.
85558439
Development of an Alkali Transfer Photocathode for Large Area Microchannel Plate-Based Photodetectors
The goal of the Large Area Picosecond Photodetector collaboration is to produce 8-inch by 8-inch microchannel plate-based photodetectors, with fast timing resolution of the order of 1-100 ps and high spatial resolution of 0.1-10 mm. At Argonne, the transfer photocathode process being developed is based on a recipe for manufacturing photomultiplier cathodes. Starting with a commercial PMT fabrication facility, the photocathode recipe and growth system will be scaled up using a custom-built glass vessel to produce transfer photocathodes. This leads to the production of the 8-inch by 8-inch photocathode that will be incorporated with the photodetector assembly system.
118071326
High Performance Photocathodes based on Molecular Beam Epitaxy Deposition for Next Generation Photo Detectors and Light Sources
The development of high-performance photocathodes is a key challenge for future accelerator and particle physics applications. In this paper photocathode growth through molecular beam epitaxy is introduced as a promising technique to obtain robust, highly efficient alkali-antimonide based photocathodes. Recent research shows that the quantum efficiency of photocathodes can be significantly enhanced through control of the photocathode crystallinity. Molecular beam epitaxy allows for cost-effective growth of large-area photocathodes with excellent control of the stoichiometry and crystallinity, making photocathodes with peak quantum efficiencies exceeding 35% routine.