5,016 research outputs found

    Properties of the scalar mesons f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710)

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    In the three-state mixing framework, considering the possible glueball components of η\eta and η\eta^\prime, we investigate the hadronic decays of f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710) into two pseudoscalar mesons. The quarkonia-glueball content of the three states is determined from the fit to the new data presented by the WA102 Collaboration. We find that these data are insensitive to the possible glueball components of η\eta and η\eta^\prime. Furthermore, we discuss some properties of the mass matrix describing the mixing of the isoscalar scalar mesons.Comment: Latex 14 pages including 1 eps figur

    Nonadiabatic dynamics and geometric phase of an ultrafast rotating electron spin

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    The spin in a rotating frame has attracted a lot of attentions recently, as it deeply relates to both fundamental physics such as pseudo-magnetic field and geometric phase, and applications such as gyroscopic sensors. However, previous studies only focused on adiabatic limit, where the rotating frequency is much smaller than the spin frequency. Here we propose to use a levitated nano-diamond with a built-in nitrogen-vacancy (NV) center to study the dynamics and the geometric phase of a rotating electron spin without adiabatic approximation. We find that the transition between the spin levels appears when the rotating frequency is comparable to the spin frequency at zero magnetic field. Then we use Floquet theory to numerically solve the spin energy spectrum, study the spin dynamics and calculate the geometric phase under a finite magnetic field, where the rotating frequency to fulfill the resonant transition condition could be greatly reduced.Comment: 6+2 pages, 3+1 figure

    A proposal on the search for the hybrid with IG(JPC)=1(1+)I^G(J^{PC})=1^-(1^{-+}) in the process J/ψρωππJ/\psi\to\rho\omega\pi\pi at upgraded BEPC/BES

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    The moment expressions for the boson resonances X with spin-parity 0++, 1-+, 1++, and 2++ possibly produced in the process J/ψρXJ/\psi\to\rho X, Xb1(1235)πX\to b_1(1235)\pi, b1ωπb_1\to \omega \pi are given in terms of the generalized moment analysis method. The 1-+ resonance can be distinguished from other resonances by means of these moments except for some rather special cases. The suggestion that the search for the 1-+ hybrid can be performed in the above decay channel at upgraded BEPC/BES is presented.Comment: Latex 13 pages, no figur

    Excited Heavy Quarkonium Production at the LHC through WW-Boson Decays

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    Sizable amount of heavy-quarkonium events can be produced through WW-boson decays at the LHC. Such channels will provide a suitable platform to study the heavy-quarkonium properties. The "improved trace technology", which disposes the amplitude M{\cal M} at the amplitude-level, is helpful for deriving compact analytical results for complex processes. As an important new application, in addition to the production of the lower-level Fock states (QQˉ)[1S]>|(Q\bar{Q'})[1S]> and (QQˉ)[1P]>|(Q\bar{Q'})[1P]>, we make a further study on the production of higher-excited (QQˉ)>|(Q\bar{Q'})>-quarkonium Fock states (QQˉ)[2S]>|(Q\bar{Q'})[2S]>, (QQˉ)[3S]>|(Q\bar{Q'})[3S]> and (QQˉ)[2P]>|(Q\bar{Q'})[2P]>. Here (QQˉ)>|(Q\bar{Q'})> stands for the (ccˉ)>|(c\bar{c})>-charmonium, (cbˉ)>|(c\bar{b})>-quarkonium and (bbˉ)>|(b\bar{b})>-bottomonium respectively. We show that sizable amount of events for those higher-excited states can also be produced at the LHC. Therefore, we need to take them into consideration for a sound estimation.Comment: 7 pages, 9 figures and 6 tables. Typo errors are corrected, more discussions and two new figures have been adde

    Doubly Heavy Baryon Production at A High Luminosity e+ee^+ e^- Collider

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    Within the framework of nonrelativistic QCD, we make a detailed discussion on the doubly heavy baryon production through the e+ee^+ e^- annihilation channel, e+eγ/Z0ΞQQ+Qˉ+Qˉe^{+}e^{-}\rightarrow\gamma/Z^0 \rightarrow \Xi_{QQ^{\prime}} +\bar{Q} +\bar{Q^{\prime}}, at a high luminosity e+ee^{+}e^{-} collider. Here Q()Q^{(\prime)} stands for the heavy bb or cc quark. In addition to the channel through the usually considered diquark state (QQ)[3S1]3ˉ(QQ^{\prime})[^3S_1]_{\bf\bar{3}}, contributions from the channels through other same important diquark states such as (QQ)[1S0]6(QQ^{\prime})[^1S_0]_{\bf 6} have also been discussed. Uncertainties for the total cross sections are predicted by taking mc=1.80±0.30m_c=1.80\pm0.30 GeV and mb=5.10±0.40m_b=5.10\pm0.40 GeV. At a super ZZ-factory running around the Z0Z^0 mass and with a high luminosity up to L10341036cm2s1{\cal L} \propto 10^{34}\sim 10^{36}{\rm cm}^{-2} {\rm s}^{-1}, we estimate that about 1.1×10571.1\times10^{5 \sim 7} Ξcc\Xi_{cc} events, 2.6×10572.6\times10^{5 \sim 7} Ξbc\Xi_{bc} events and 1.2×10461.2\times 10^{4 \sim 6} Ξbb\Xi_{bb} events can be generated in one operation year. Such a ZZ-factory, thus, will provide a good platform for studying the doubly heavy baryons in comparable to the CERN large hadronic collider.Comment: 9 pages, 4 figures. To be published in Phys.Rev.

    PS3^3: Precise Patch Presence Test based on Semantic Symbolic Signature

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    During software development, vulnerabilities have posed a significant threat to users. Patches are the most effective way to combat vulnerabilities. In a large-scale software system, testing the presence of a security patch in every affected binary is crucial to ensure system security. Identifying whether a binary has been patched for a known vulnerability is challenging, as there may only be small differences between patched and vulnerable versions. Existing approaches mainly focus on detecting patches that are compiled in the same compiler options. However, it is common for developers to compile programs with very different compiler options in different situations, which causes inaccuracy for existing methods. In this paper, we propose a new approach named PS3, referring to precise patch presence test based on semantic-level symbolic signature. PS3 exploits symbolic emulation to extract signatures that are stable under different compiler options. Then PS3 can precisely test the presence of the patch by comparing the signatures between the reference and the target at semantic level. To evaluate the effectiveness of our approach, we constructed a dataset consisting of 3,631 (CVE, binary) pairs of 62 recent CVEs in four C/C++ projects. The experimental results show that PS3 achieves scores of 0.82, 0.97, and 0.89 in terms of precision, recall, and F1 score, respectively. PS3 outperforms the state-of-the-art baselines by improving 33% in terms of F1 score and remains stable in different compiler options.Comment: Accepted to ICSE 2024; Camera-ready versio

    Study on Unloading-wet Swelling Mechanism of Upper Arch Deformation of Mudstone Subgrade in a High-speed Railway

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    Mudstone subgrade may exhibit rather complicated deformation behavior under the coupling effect of unloading and wet swelling caused by subgrade excavation. To study the deformation mechanism of mudstone subgrade, mudstones were sampled from the NO.3 branch tunnel of Badong section of Zhengzhou-Wanzhou High-speed Railway and a series of unloading and wet-swelling tests were carried out on them. We studied the long-term deformation behavior of mudstone subgrade caused by excavation based on a creep test with unloading conditions. The expansion rate of the complete mudstone cylinder samples was extremely low under the wetting and drying cycle, while that of the soil samples after the disintegration of complete mudstone was between 1% and 10% when immersed in water. Excavation unloading damage, groundwater infiltration, long-term creep deformation, dry-wet cycle, and hot-cold alternation catalyzed each other, leading to the aggravation of mudstone disintegration and the obvious increase of expansibility of underwater mudstone after disintegration. The maximum arch deformation of mudstone subgrade can be divided into three parts: the rebound deformation during short-term excavation, the creep deformation related to time and the wet-swelling deformation. Generally, the creep deformation would not converge in two years if support measures were not taken, the wet-swelling deformation could tend to a steady value after a certain period of excavation
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