2,223 research outputs found

    X(1812) in Quarkonia-Glueball-Hybrid Mixing Scheme

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    Recently a JPC=0++J^{PC}=0^{++} (X(1812)) state with a mass near the threshold of ω\omega and ϕ\phi has been observed by the BES collaboration in J/ψγωϕJ/\psi \to \gamma \omega \phi decay. It has been suggested that it is a IG=0+I^G = 0^+ state. If it is true, this state fits in a mixing scheme based on quarkonia, glueball and hybrid (QGH) very nicely where five physical states are predicted. Together with the known f0(1370)f_0(1370), f0(1500)f_0(1500), f0(1710)f_0(1710), and f0(1790)f_0(1790) states, X(1812) completes the five members in this family. Using known experimental data on these particles we determine the ranges of the mixing parameters and predict decay properties for X(1812). We also discuss some features which may be able to distinguish between four-quark and hybrid mixing schemes.Comment: 15 pages, 2 figures, 3 table

    A preliminary study of photometric redshifts based on the Wide Field Survey Telescope

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    The Wide Field Survey Telescope (WFST) is a dedicated time-domain multi-band (uu, gg, rr, ii, and zz) photometric survey facility under construction. In this paper, we present a preliminary study that assesses the quality of photometric redshifts based on WFST by utilizing mock observations derived with the galaxy catalog in the COSMOS/UltraVISTA field. We apply the template fitting technique to estimate photometric redshifts by using the ZEBRA photometric-redshift code and adopting a modified set of adaptive templates. We evaluate the bias (median relative offset between the output photometric redshifts and input redshifts), normalized median absolute deviation (σNMAD\sigma_{\rm NMAD}) and outlier fraction (foutlierf_{\rm outlier}) of photometric redshifts in two typical WFST observational cases, the single 30-second exposure observations (hereafter shallow mode) and co-added 50-minute exposure observations (hereafter deep mode). We find bias\la0.006, \sigma_{\rm NMAD}\la0.03, and f_{\rm outlier}\la5\% in the shallow mode and bias0.005\approx 0.005, σNMAD0.06\sigma_{\rm NMAD}\approx 0.06, and foutlier17%f_{\rm outlier}\approx 17\%--27%27\% in the deep mode, respectively, under various lunar phases. Combining the WFST mock observational data with that from the upcoming CSST and Euclid surveys, we demonstrate that the zphotz_{\rm phot} results can be significantly improved, with foutlier1%f_{\rm outlier}\approx 1\% and σNMAD0.02\sigma_{\rm NMAD}\approx 0.02.Comment: 20 pages, 13 figures. Accepted for publication in Research in Astronomy and Astrophysics (RAA

    Exact Eigenfunctions of NN-Body system with Quadratic Pair Potential

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    We obtain all the exact eigenvalues and the corresponding eigenfunctions of NN-body Bose and Fermi systems with Quadratic Pair Potentials in one dimension. The originally existed first excited state level is missing in one dimension, which results from the operation of symmetry or antisymmetry of identical particles. In two and higher dimensions, we give all the eigenvalues and the analytical ground state wave functions and the number of degeneracy. Through the comparison with Avinash Khare's results, we have perfected his results.Comment: 7 pages,1 figur

    The single t-quark productions via the flavor-changing processes in the topcolor-assisted technicolor model at the hadron colliders

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    In the framework of topcolor-assisted technicolor(TC2) model, there exist tree-level flavor-changing (FC) couplings which can result in the loop-level FC coupling tcgtcg. Such tcgtcg coupling can contribute significant clues at the forthcoming Large Hadron Collider (LHC) experiments. In this paper, based on the TC2 model, we study some single t-quark production processes involving tcgtcg coupling at the Tevatron and LHC: pp(ppˉ)tqˉ(q=u,d,s),tgpp(p\bar{p})\to t\bar{q}(q=u,d,s),tg. We calculate the cross sections of these processes. The results show that the cross sections at the Tevatron are too small to observe the signal, but at the LHC it can reach a few pb. With the high luminosity, the LHC has considerable capability to find the single t-quark signal produced via some FC processes involving coupling tcgtcg. On the other hand, these processes can also provide some valuable information of the coupling tcgtcg with detailed study of the processes and furthermore provide the reliable evidence to test the TC2 model.Comment: 15 pages, 10 figure

    Berry Phase in Neutrino Oscillations

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    We study the Berry phase in neutrino oscillations for both Dirac and Majorana neutrinos. In order to have a Berry phase, the neutrino oscillations must occur in a varying medium, the neutrino-background interactions must depend on at least two independent densities, and also there must be CP violation if the neutrino interactions with matter are mediated only by the standard model W and Z boson exchanges which implies that there must be at least three generations of neutrinos. The CP violating Majorana phases do not play a role in generating a Berry phase. We show that a natural way to satisfy the conditions for the generation of a Berry phase is to have sterile neutrinos with active-sterile neutrino mixing, in which case at least two active and one sterile neutrinos are required. If there are additional new CP violating flavor changing interactions, it is also possible to have a non-zero Berry phase with just two generations.Comment: RevTex 16 pages, no figures, new discussions about sterile neutrino added,typos corrected and errors in references correcte

    Study on contributions of hadronic loops to decays of J/ψJ/\psi\to vector ++ pseudoscalar mesons

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    In this work, we evaluate the contributions of the hadronic loops to the amplitudes of J/ψPVJ/\psi\to PV where PP and VV denote light pseudoscalar and vector mesons respectively. By fitting data of two well measured channels of J/ψPVJ/\psi\to PV, we obtain the contribution from the pure OZI process to the amplitude which is expressed by a phenomenological quantity GSPV|\mathcal{G}^{PV}_{S}|, and a parameter α\alpha existing in the calculations of the contribution of hadronic loops. In terms of α\alpha and GSPV|\mathcal{G}^{PV}_{S}|, we calculate the branching ratios of other channels and get results which are reasonably consistent with data. Our results show that the contributions from the hadronic loops are of the same order of magnitude as that from the OZI processes and the interference between the two contributions are destructive. The picture can be applied to study other channels such as PP or VV of decays of J/ψJ/\psi.Comment: 9 pages, 3 figures, 1 table. Some descriptions changed, more references added and typos corrected. Published version in PR

    Transport Measurements on Nano-engineered Two Dimensional Superconducting Wire Networks

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    Superconducting triangular Nb wire networks with high normal-state resistance are fabricated by using a negative tone hydrogen silsesquioxane (HSQ) resist. Robust magnetoresistance oscillations are observed up to high magnetic fields and maintained at low temperatures, due to the eective reduction of wire dimensions. Well-defined dips appear at integral and rational values (1/2, 1/3, 1/4) of the reduced flux f = Phi/Phi_0, which is the first observation in the triangular wire networks. These results are well consistent with theoretical calculations for the reduced critical temperature as a function of f.Comment: 4 pages, 3 figure

    A new parametric equation of state and quark stars

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    It is still a matter of debate to understand the equation of state of cold supra-nuclear matter in compact stars because of unknown on-perturbative strong interaction between quarks. Nevertheless, it is speculated from an astrophysical view point that quark clusters could form in cold quark matter due to strong coupling at realistic baryon densities. Although it is hard to calculate this conjectured matter from first principles, one can expect the inter-cluster interaction to share some general features to nucleon-nucleon interaction. We adopt a two-Gaussian component soft-core potential with these general features and show that quark clusters can form stable simple cubic crystal structure if we assume Gaussian form wave function. With this parameterizing, Tolman-Oppenheimer-Volkoff equation is solved with reasonable constrained parameter space to give mass-radius relation of crystalline solid quark star. With baryon densities truncated at 2 times nuclear density at surface and range of interaction fixed at 2fm we can reproduce similar mass-radius relation to that obtained with bag model equations of state. The maximum mass ranges from about 0.5 to 3 solar mass. Observed maximum pulsar mass (about 2 solar mass) is then used to constrain parameters of this simple interaction potential.Comment: 5 pages, 2 figure

    Experimental realization of continuous-time quantum walks on directed graphs and their application in PageRank

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    PageRank is an algorithm used by Google Search to rank web pages in their search engine results. An important step for quantum networks is to quantize the classical protocol as quantum mechanics provides computational resources that can be used to outperform classical algorithms. In this paper, we experimentally realize continuous-time quantum walks for directed graphs with non-Hermitian adjacency matrices by using linear optical circuits and single photons. We find that the node classical centrality in a directed graph is correlated with the maximum node probability resulting from a continuous-time quantum walk and then demonstrate PageRank. Our work opens up an avenue of applications of quantum information in real-life tasks
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