作者机构：
[Qiang Wang; Jia-Hao Shi; Zhi-Ying Qin; Wen-Chao Zhang] School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China;[An-Ke Lei] Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China;[Zhi-Lei She] School of Mathematical and Physical Sciences, Wuhan Textile University, Wuhan 430200, China;[Yu-Liang Yan; Ben-Hao Sa] China Institute of Atomic Energy, P. O. Box 275 (10), Beijing 102413, China;[Kai-Fan Ye] School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China<&wdkj&>Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China
摘要：
In this work we investigate the J/ψ production in proton-proton collisions at the center-of-mass energy (s) equal to 2.76, 5.02, 7, 8, and 13 TeV with the parton and hadron cascade model PACIAE 2.2a. It is based on PYTHIA but extended considering the partonic and hadronic rescatterings before and after hadronization, respectively. In the PYTHIA sector the J/ψ production quantum chromodynamics processes are selected specially and a bias factor is proposed correspondingly. The calculated total cross sections, the transverse momentum differential, and the rapidity differential cross sections of J/ψ in the forward rapidity region reproduce the corresponding experimental measurements reasonably well. In the mid-rapidity region, the double-differential cross sections at s=5.02 , 7, and 13 TeV are also in a good agreement with the experimental data. Moreover, we interpolate the double-differential cross section as well as the total cross section of J/ψ in the mid-rapidity region at s=8 TeV, which could be validated if the experimental data are available.
摘要：
The security performance of image encryption schemes based on chaotic systems has been greatly improved. Specifically, those chaotic systems with high-dimension or special attractors have shown more benefits for enhancing performance. By introducing the tangent function, a 4-dimensional chaotic system with infinite coexisting attractors is constructed. And the dynamical behaviors are analyzed through phase diagrams, bifurcation diagrams, Lyapunov exponent spectrum and spectral entropy complexity diagram. The results demonstrate that the system exhibits self-replication with respect to the initial value y0 and possesses rich dynamical properties, such as infinite coexisting attractors, sensitivity to initial values and period-doubling bifurcation. These characteristics make it suitable for chaotic cryptography applications. Subsequently, a lossless double color image encryption scheme is designed based on the constructed system. The scheme adopts a diffusion-scrambling-diffusion processing method, and cleverly utilizes the information of the original plaintext image in the scrambling process, which significantly enhances the ability to resist known plaintext attacks or selected plaintext attacks. The experimental results verify that the designed algorithm not only effectively encrypts color and grayscale images, but also allows for encryption images of any size. Moreover, the algorithm implementation process is efficient and ensures high security performance, effectively resisting differential attacks, rotation attacks and cropping attacks. This research exploration on the chaotic characteristics of the nonlinear high-dimensional system and its application in image encryption is expected to provide theoretical guidance in the field of secure communication.
作者机构：
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China;Lanzhou University, Lanzhou, Gansu 730000, China;University of Chinese Academy of Sciences, Beijing 100049, China;[Hongxin Dong] Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, Nanjing, Jiangsu 210023, China;Key Laboratory of Particle Physics and Particle Irradiation (MOE), Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, China
摘要：
We present a phenomenological extraction of transversity distribution functions and Collins fragmentation functions by simultaneously fitting to semi-inclusive deep inelastic scattering and electron-positron annihilation data. The analysis is performed within the transverse-momentum-dependent factorization formalism, and sea quark transversity distributions are taken into account for the first time. We find the u¯ quark favors a negative transversity distribution, while that of the d¯ quark is consistent with zero according to the current accuracy. In addition, based on a combined analysis of world data and simulated data, we quantitatively demonstrate the impact of the proposed Electron-Ion Collider in China on precise determinations of the transversity distributions, especially for sea quarks, and the Collins fragmentation functions.
期刊：
Sustainable Materials and Technologies,2024年40:e00875 ISSN：2214-9937
通讯作者：
Wei Sun<&wdkj&>Zhihong Zhu
作者机构：
[Songlin Zhao; Chengcai Wang; Luhang Cai; Yipeng Chen; Zhihong Zhu] Institute of Nano-science and Nano-technology, College of Physical Science and Technology, Central China Normal University, Wuhan 430079, PR China;[Wei Sun] Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
通讯机构：
[Wei Sun] K;[Zhihong Zhu] I;Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China<&wdkj&>Institute of Nano-science and Nano-technology, College of Physical Science and Technology, Central China Normal University, Wuhan 430079, PR China
摘要：
The fabrication of distinct sites on the carbonized substrate as bifunctional oxygen catalysts is pivotal for enhancing the practicality of Zn-air batteries, but remains a formidable challenge. Herein, a gas doping strategy is reported for anchoring Ni nanoparticles and further increasing FeNx sites on biomass-derived Fe, N, and P co-doped porous carbonized materials as highly efficient bifunctional electrocatalysts. The inherent porous structure and heteroatom of rattan tea provide a superior carrier for Fe and Ni-based active species. Notably, the as-prepared Ni@FeNPC/Fef shows unprecedented capability for oxygen reduction reaction and excellent catalytic activity for oxygen evolution reaction. In situ Raman spectroscopy studies shed light on the role of FeNx and heteroatom-doped carbon during the oxygen reduction reaction. Density functional theory calculations verify the catalytic mechanism on various active sites of Ni@FeNPC/Fef. Moreover, the Ni@FeNPC/Fef-based Zn-air battery maintains cyclic stability for over 400 h with negligible voltage degradation. This strategy endows a novel route for converting biomass into practical electrocatalysts for diverse energy-related systems.
作者机构：
[Xiao, Yuxuan; Xie, Guohua] The Institute of Flexible Electronics (Future Technologies), Xiamen University, Xiamen 361005, China;[Xue, Qin] Department of Physical Science and Technology, Central China Normal University, Wuhan 430079, China;[Liu, Xiaoke; Gao, Feng] Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
通讯机构：
[Xiaoke Liu; Feng Gao] D;Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
作者机构：
School of Physical Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046, People's Republic of China;Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi, Xinjiang 830011, People's Republic of China;na.wang@xao.ac.cn, yuanjp@xao.ac.cn;Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, People's Republic of China;Xinjiang Key Laboratory of Radio Astrophysics, 150 Science 1-Street, Urumqi, Xinjiang 830011, People's Republic of China
摘要：
We report the timing analysis of PSR J1846−0513, a pulsar discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey. The pulsar possesses a spin period of 23.36 ms and a spin-down rate ( ) of 1.0106(3) × 10−18 s s−1, and it is located in an eccentric orbit (e ∼0.208) with an orbital period of 0.61 days. The characteristic age and surface magnetic field of the pulsar are found to be 366.62 Myr and 4.9178 × 109 G, respectively, indicating that it is a recycled pulsar. Using over two years of timing data, we measure the periastron advance = 0.8956(8) deg yr−1. By assuming that this effect is purely relativistic, we have estimated the total mass M = 2.6287(35)M⊙ and obtained an upper limit for the pulsar mass and a lower limit for the companion's mass. Our results indicate that this is a double neutron star system.
作者机构：
[Qiu, Yi-Wei; Feng, Sheng-Qin] China Three Gorges Univ, Coll Sci, Yichang 443002, Peoples R China.;[Feng, Sheng-Qin] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[Feng, Sheng-Qin] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[Feng, Sheng-Qin] China Three Gorges Univ, Ctr Astron & Space Sci, Yichang 443002, Peoples R China.
通讯机构：
[Feng, SQ ] C;China Three Gorges Univ, Coll Sci, Yichang 443002, Peoples R China.;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;China Three Gorges Univ, Ctr Astron & Space Sci, Yichang 443002, Peoples R China.
摘要：
We investigate the magnetized QCD matter and chiral phase transition in a (2 thorn 1)-flavor Nambu-Jona-Lasinio (NJL) model at finite temperature and chemical potential by comparing the contributions from the tensor spin polarization (TSP) and anomalous magnetic moment (AMM) of quarks. For light u and d quarks, when TSP and AMM are not considered, the magnetized system is characterized by magnetic catalysis. The introduction of TSP will further enhance the magnetic catalytic characteristics. On the other hand, when AMM is introduced, the phase-transition temperature decreases with the magnetic field, which is the feature of inverse magnetic catalysis. The phase diagram of u and d quarks will change from the crossover phase transition to the first order phase transition with the increase of magnetic field and chemical potential when AMM is induced. The phase diagram will not change from the crossover phase transition to the first-order phase transition when TSP is induced. For the phase diagram of strange s quark, whether TSP or AMM is induced, the phase diagram will keep a crossover phase transition with the increase of magnetic field and chemical potential.
摘要：
The semitauonic
$$ {B}_c^{-}\to J/\psi {\tau}^{-}{\overline{\nu}}_{\tau } $$
decay provides an ideal and clean mode to scrutinize possible new physics effects in
$$ b\to c{\tau}^{-}{\overline{\nu}}_{\tau } $$
transitions as indicated by the current data on R(D(*)) anomalies. In this work, we use the spin density matrix method to obtain the maximum information on the underlying physics of
$$ {B}_c^{-}\to J/\psi {\tau}^{-}{\overline{\nu}}_{\tau } $$
decay with both polarized τ lepton and J/ψ meson. Their subsequent decays, with J/ψ → μ+μ− as well as τ− → π−ντ, τ− → ρ−ντ and
$$ {\tau}^{-}\to {\ell}^{-}{\overline{\nu}}_{\ell }{\nu}_{\tau } $$
, are exploited to extract the energy and angular distributions of the charged final-state particles in the processes. Starting with the most general effective Hamiltonian relevant for the
$$ b\to c{\tau}^{-}{\overline{\nu}}_{\tau } $$
transitions, including all possible Lorentz structures of the dimension-six operators with both left- and right-handed neutrinos, we first derive the five-fold differential decay rate in terms of the visible final-state kinematics. From this distribution, we then construct in total 34 normalized observables, among which nine refer to the CP-violating triple product asymmetries that vanish within the Standard Model. We also construct five new observables based on the combinations of these normalized observables that can only be attributed to the right-handed neutrinos. On the other hand, considering the low statistics of the fully differential distribution, we introduce some integrated observables with only one kinematic variable left, which are more promising to be measured due to the largely increased statistics. The sensitivities of all these observables to the different new physics scenarios are investigated in detail. Finally, assuming an ideal circumstance, we give an estimate of the statistical uncertainties of the nine CP-conserving observables at LHCb and found that τ− → π−ντ has the highest analyzing power among the three τ decay channels.
摘要：
In the context of constructing digital power grid, there has been significant attention on the methods to accurately and promptly obtain the physical field information of power equipment. The numerical methods, such as finite element analysis (FEA), are limited by offline computation and cannot meet the safety and timeliness requirements of the power grid. In this letter, a method based on deep neural networks (DNN) is proposed for rapidly predicting the magnetic field distribution of reactors. After training on magnetic field data generated by FEA simulation, the DNN takes the reactor current value as input and gets the simulation results processed using principal component analysis (PCA) within 1 s. The trained DNN has a mean absolute percentage error (MAPE) of 0.012% in predicting the magnetic field distribution of reactor. This method demonstrates the viability of replacing traditional simulation methods with DNN to expand the applications of digital twin in the power grid.
作者机构：
[Ketel, T.; Mulder, M.; Tuning, N.; Perez, D. H. Campora; Mauri, A.; Usachov, A.; de Vries, J. A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Sanchez Gras, C.; Veronesi, M.; Akiba, K.; Aaij, R.; Aaij, R; Snoch, A.; De Bruyn, K.; van Beuzekom, M.; Biolchini, A.; Martinez, M. Lucio; Jans, E.; Vos, K.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Grecu, A. T.; Merk, M.; Onderwater, C. J. G.; Bolognani, C. S.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Pawley, C. J.; Soares, M. Senghi; Klaver, S.; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subatom Phys, Amsterdam, Netherlands.;[Massafferri, A.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; de Souza Leite, J. Baptista; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; Carneiro Da Graca, U. De Freitas; dos Reis, A. C.; Santovetti, E.] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil.;[De Paula, B. Souza; Lopes, J. H.; Polycarpo, E.; Souza De Almeida, F. L.; Gandelman, M.; Gobel, C.; Rangel, M. S.; Hicheur, A.; Otalora Goicochea, J. M.; Garcia, L. Meyer; Rodrigues, F. Ferreira; De Paula, L.; Nasteva, I.; Amato, S.] Univ Fed Rio De Janeiro UFRJ, Rio De Janeiro, Brazil.;[Cai, H.; Bian, L.; Liu, G.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Huang, X.; Li, H.; Li, A.; Hu, X.; Grauges, E.; Tan, Y.; Gu, C.; Gong, G.; Wang, X.; Bursche, A.; Kang, Y.; Fang, B.; Qi, H. R.; Chen, C.; Zhu, X.; Sun, L.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Chen, S.; Greeven, L. M.; Li, P. -R.; Tobin, M.; Miao, D.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys IHEP, Beijing, Peoples R China.
摘要：
A combined amplitude analysis is performed for the decays B0-+ D0D thorn s & pi;- and B thorn -+ D-D thorn s & pi; thorn , which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton -proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. Two new resonant states with masses of 2.908 ⠂ 0.011 ⠂ 0.020 GeV and widths of 0.136 ⠂ 0.023 ⠂ 0.013 GeV are observed, which decay to D thorn s & pi; thorn and D thorn s & pi;- respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content 1/2cs over bar ud over bar ⠃, and the latter state is a neutral tetraquark composed of 1/2cs over bar u over bar d ⠃ quarks. Both states are found to have spin-parity of 0 thorn , and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.
作者机构：
[Wu, Yuanfang; Xu, Mingmei] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[Wu, Yuanfang; Xu, Mingmei] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Yuanfang Wu] K;Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
In the QCD, a transition restoring the chiral symmetry occurs at a high temperature and density. Searching for the signals of the QCD phase transition is one of the goals of the current relativistic heavy-ion physics programs. The metastable state is a unique feature of the first-order phase transition. Using the van der Waals equation of state, the role of the metastable state in finite-size effects is analyzed. It is found that the finite-size effects of the first-order phase transition are closely related to the metastable state. Metastability can be observed in the distribution of the order parameters and the probability of its occurrence depends on the system scale. A sizable probability of the metastability requires a small enough system size. The possibility of observing the metastability in the RHIC/BES is discussed.
摘要：
In this work, we investigate the semileptonic decays of
$$B_{c}$$
meson to
$$\eta _{c}(1S,2S,3S)$$
,
$$\psi (1S,2S,3S)$$
and X(3872) within the framework of covariant light-front quark model (CLFQM). We combine the helicity amplitudes via the corresponding form factors to obtain the branching ratios of the semileptonic decays
$$B_{c}\rightarrow \eta _{c}(1S, 2S, 3S)\ell \nu _{\ell }$$
,
$$B_{c}\rightarrow \psi (1S, 2S, 3S))\ell \nu _{\ell }$$
and
$$B_{c}\rightarrow X(3872)\ell \nu _{\ell }$$
, with
$$\ell =e,\mu ,\tau $$
. In view of the
$$R_{J/\Psi }$$
anomaly released by the LHCb collaboration, it is necessary to systematically calculate the ratios
$$R_X$$
with
$$X=\psi (1S,2S,3S),\eta _c(1S,2S,3S),X(3872)$$
, which are helpful for checking the lepton flavor universality (LFU). We also take into account another two physical observables, the longitudinal polarization fraction
$$f_{L}$$
and the forward–backward asymmetry
$$A_{FB}$$
, which can provide new clues for understanding the
$$R_{J /\Psi }$$
anomaly. Such theoretical predictions are necessary and interesting, and can be tested in future LHCb experiments.
作者：
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellan;Abudinen, F.;Ackernley, T.;...
期刊：
EUROPEAN PHYSICAL JOURNAL C,2023年83(8):1-7 ISSN：1434-6044
通讯作者：
Aaij, R
作者机构：
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Aaij, R; Snoch, A.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Da Graca, U. De Freitas Carneiro; Massafferri, A.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Leite, J. Baptista de Souza] CBPF, Rio De Janeiro, Brazil.;[De Paula, B. Souza; Lopes, J. H.; Goicochea, J. M. Otalora; Polycarpo, E.; Gandelman, M.; Rangel, M. S.; Hicheur, A.; Gomes, A.; Garcia, L. Meyer; Rodrigues, F. Ferreira; De Paula, L.; Nasteva, I.; Amato, S.; De Almeida, F. L. Souza] Univ Fed Rio de Janeiro, Rio de Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
作者：
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellan;Abudinen, F.;Ackernley, T.;...
期刊：
中国物理C,2023年47(9):14-26 ISSN：1674-1137
通讯作者：
Aaij, R
作者机构：
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Aaij, R; Snoch, A.; van Beuzekom, M.; Biolchini, A.; Martinez, M. Lucio; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[De Freitas Carneiro Da Graca, U.; Massafferri, A.; De Miranda, J. M.; Baptista De Souza Leite, J.; Falcao, L. N.; Bediaga, I. B.; Torres, M. Cruz; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fisicas CBPF, Rio De Janeiro, Brazil.;[Lopes, J. H.; Goicochea, J. M. Otalora; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Garcia, L. Meyer; Barbetti, M.; De Paula, L.; Nasteva, I.; Amato, S.] Univ Fed Rio De Janeiro UFRJ, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Hu, X.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Wang, J.; Chen, S.; Tobin, M.; Grieser, N. A.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.; Carli, I.] Inst High Energy Phys IHEP, Beijing, Peoples R China.
摘要：
A first search for the Xi(+)(bc) -> J/psi Xi c+ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb(-1) recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of and standard deviations at masses of 6571 and 6694 MeV/c(2), respectively. Upper limits are set on the Xi(+)(bc) baryon production cross-section times the branching fraction relative to that of the B-c(+) -> J/psi Xi(+)(c) decay at centre-of-mass energies of 8 and 13 TeV, in the Xi(+)(bc) and in the rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to, respectively. Upper limits are presented as a function of the Xi(+)(bc) mass and lifetime.
摘要：
A compact 4-port coplanar waveguide (CPW) fed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with enhanced isolation is proposed to operate from 3.66 GHz to 16.61 GHz with 127.78% impedance bandwidth. The proposed antenna system consists of 4 orthogonal arrays of monopole antennas improved by four iterations. The UWB characteristic of the antenna is obtained from an improved monopole antenna fed by CPW. The final MIMO antenna is machined on a Rogers 4003C substrate with dimensions of 60 x 60 x 0.3 mm(3). The orthogonal arrangement of antennas brings about the polarization diversity and certain isolation of MIMO antennas. Four rows of orthogonal metasurface elements with via holes and the ring of the backplane further improve the isolation between antenna elements in the MIMO system. The MIMO antenna has an impedance bandwidth of 12.95 GHz with S-11 < -10 dB and good isolation (S-21 =S-41 < -30 dB and S-31 < -20 dB). In particular, S31 is always less than -25 dB at frequencies greater than 6 GHz. The measured results of MIMO antenna agree with the simulated results. The optimized MIMO antenna has excellent performance in many aspects, such as UWB, compact size, omnidirectional radiation, enhanced isolation and high efficiency, which means that it has application potential in UWB wireless communication systems.
