7,978 research outputs found

    Double pion production in NNNN and NˉN\bar{N}N collisions

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    With an effective Lagrangian approach, we give a full analysis on the NNNNππNN \to NN\pi\pi and NˉNNˉNππ\bar{N}N\to \bar{N}N\pi\pi reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from Δ\Delta, N(1440)N^*(1440), Δ(1600)\Delta(1600) and Δ(1620)\Delta(1620) resonances. Our calculations also indicate sizeable contributions from nucleon poles for the energies close to the threshold. A good description to the existing data of different isospin channels of NNNNππNN\to NN\pi\pi and NˉNNˉNππ\bar{N}N\to \bar{N}N\pi\pi for beam energies up to 2.2 GeV is reached. Our results provide important implications to the ABC effect and guildlines to the future experimental projects at COSY, HADES and HIRFL-CSR. We point out that the \={P}ANDA at FAIR could be an essential place for studying the properties of baryon resonances and the data with baryon and anti-baryon in final states are worth analyzing.Comment: Invited plenary talk at the 11th International Workshop on Meson Production, Properties and Interaction (MESON2010), 10-15 June, 2010, Krakow, Polan

    Phenomenological analysis of the double pion production in nucleon-nucleon collisions up to 2.2 GeV

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    With an effective Lagrangian approach, we analyze several NN \to NN\pi\pi channels by including various resonances with mass up to 1.72 GeV. For the channels with the pion pair of isospin zero, we confirm the dominance of N*(1440)\to N\sigma in the near threshold region. At higher energies and for channels with the final pion pair of isospin one, we find large contributions from N*(1440)\to \Delta\pi, double-Delta, \Delta(1600) \to N*(1440)\pi, \Delta(1600) \to \Delta\pi and \Delta(1620) \to \Delta\pi. There are also sizeable contributions from \Delta \to \Delta\pi, \Delta \to N\pi, N \to \Delta\pi and nucleon pole at energies close to the threshold. We well reproduce the total cross sections up to beam energies of 2.2 GeV except for the pp\to pp\pi^0\pi^0 channel at energies around 1.1 GeV and our results agree with the existing data of differential cross sections of pp \to pp\pi^+\pi^-, pp \to nn\pi^+\pi^+ and pp \to pp\pi^0\pi^0 which are measured at CELSIUS and COSY.Comment: 36 pages, 18 figure

    Detection of the Rydberg States of Electrons on Superfluid Helium Confined in Microchannel Devices

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    The potential for quantum information processing with surface-state electrons (SSE) on liquid helium has been pointed out in one of the historically first proposals for quantum computing [1]. The quantized Rydberg states of the vertical motion of SSE, as well as the spin states of SSE, present two promising candidates for the experimental implementation of qubit states. However, the lack of a sensitive state-readout method for a single electron has so far prevented much progress in implementation of these states for quantum computing. In order to overcome this obstacle, this PhD project seeks to lay the experimental groundwork for the realization of Rydberg state detection of SSE on liquid helium confined in microchannel devices, as well as their potential use for spin state detection. We start from the transport measurements of SSE in a microchannel setup, since well-understood transport behavior of SSE can help us to detect the Rydberg transition. An unusual transport effect is reported and discussed. By employing the time-resolved measurements, we show that the effect is due to the dynamical interaction of the electron crystal with the surface excitations of the liquid substrate. Next, the feasibility of detecting the transition between Rydberg states in a 4-µm deep channel device is demonstrated using two different methods, the conductivity method and the image-charge method. We find that the observed transition frequency for the two lowest Rydberg states, which is in the range of 0.4 − 0.5 THz, is determined by the image charges induced by SSE in the conducting electrodes of the microchannel device and the applied potentials, and is in a good agreement with our analytical and numerical calculations. Owing to the low sensitivity of this method, the number of SSE in the device is required to be large, on the order of 104, that is the sensitivity is far below the final goal of single electron readout. Taking advantage of the LC (tank) resonating circuits, we significantly improve the measurement sensitivity by employing a resonator albeit with a relatively low quality factor. Finally, we present our ongoing experimental efforts to optimize the resonator setup, in particularly increasing its quality factor, which is an important step towards realizing an ultra-sensitive readout of the single-electron Rydberg states.Okinawa Institute of Science and Technology Graduate Universit

    AFL-Net: Integrating Audio, Facial, and Lip Modalities with a Two-step Cross-attention for Robust Speaker Diarization in the Wild

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    Speaker diarization in real-world videos presents significant challenges due to varying acoustic conditions, diverse scenes, the presence of off-screen speakers, etc. This paper builds upon a previous study (AVR-Net) and introduces a novel multi-modal speaker diarization system, AFL-Net. The proposed AFL-Net incorporates dynamic lip movement as an additional modality to enhance the identity distinction. Besides, unlike AVR-Net which extracts high-level representations from each modality independently, AFL-Net employs a two-step cross-attention mechanism to sufficiently fuse different modalities, resulting in more comprehensive information to enhance the performance. Moreover, we also incorporated a masking strategy during training, where the face and lip modalities are randomly obscured. This strategy enhances the impact of the audio modality on the system outputs. Experimental results demonstrate that AFL-Net outperforms state-of-the-art baselines, such as the AVR-Net and DyViSE

    Implications of Beach and Dune Topography on Storm Surge Dynamics on the Florida Panhandle

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

    A novel measurement of Bs0B^0_s and DsD^-_s lifetimes using semileptonic decays at LHCb

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    I report new, world-leading LHCb results on heavy meson lifetimes. We use a novel approach that suppresses the shortcomings typically associated with reconstruction of semileptonic decays, allowing for precise measurements of lifetimes and other properties in collider experiments. We achieve a 15% and a 2×2\times improvement over current best determinations of the flavor-specific Bs0B^0_s lifetime and DsD^-_s lifetime, respectively.Comment: 12 pages, 6 figures. Talk presented at the APS Division of Particles and Fields Meeting (DPF 2017), July 31-August 4, 2017, Fermilab. C17073

    Comparison on Grain Quality Between Super Hybrid and Popular Inbred Rice Cultivars Under Two Nitrogen Management Practices

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    This study was conducted to determine the differences in grain quality traits between super hybrid and popular inbred rice cultivars grown under two nitrogen (N) management practices. Field experiments were done at the Experimental Farm of Guangxi University, Guangxi Province, China in early and late rice-growing seasons in 2014. Two representative super hybrid cultivars Liangyoupeijiu (LYPJ) and Y-liangyou 1 (YLY1) and a popular inbred rice cultivar Huanghuazhan (HHZ) were grown under fixed-time N management (FTNM) and site-specific N management (SSNM) practices in each season. Grain quality traits and N uptake were measured for each cultivar. LYPJ and YLY1 had higher milling efficiency, poorer appearance and palatability, and equal nutritional value than HHZ. The higher milling efficiency and poorer appearance in LYPJ and YLY1 were associated with their higher rice width compared with HHZ. Total N application rate was reduced by 15–20% under SSNM than under FTNM, whereas there was nearly no significant difference in grain quality between SSNM and FTNM. Our results suggest that (1) strategies for grain quality improvement in super hybrid rice should be focused on appearance and palatability, and (2) replacing FTNM with SSNM can reduce N input without sacrificing grain quality in rice production

    4-Chloro-N′-(2-hydroxy­benzyl­idene)benzohydrazide monohydrate

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    The asymmetric unit of the title compound, C14H11ClN2O2·H2O, contains a Schiff base mol­ecule and a water mol­ecule of crystallization. The dihedral angle between the two aromatic rings is 27.3 (4)°. In the crystal structure, mol­ecules are linked into a two-dimensional network parallel to the bc plane by inter­molecular O—H⋯O and N—H⋯O hydrogen bonds involving the water mol­ecules
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