682 research outputs found

    Dominant Spin-Flip Effects for the Hadronic Produced J/ψJ/\psi Polarization at TEVATRON

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    Dominant spin-flip effects for the direct and prompt J/ψJ/\psi polarizations at TEVATRON run II with collision energy 1.96 TeV and rapidity cut yJ/ψ<0.6|y^{J/\psi}|<0.6, have been systematically studied, especially, the spin-flip effect for the transition of (ccˉ)8[3S1](c\bar{c})_8[^3S_1] into J/ψJ/\psi has been carefully discussed. It is found that the spin-flip effect shall always dilute the J/ψJ/\psi polarization, and with a suitable choice of the parameters a0,1a_{0,1} and c0,1,2c_{0,1,2}, the J/ψJ/\psi polarization puzzle can be solved to a certain degree. At large transverse momentum ptp_t, α\alpha for the prompt J/ψJ/\psi is reduced by 50\sim50% for f0=v2f_0 = v^2 and by 80\sim80% for f0=1f_0=1. We also study the indirect J/ψJ/\psi polarization from the bb-decays, which however is slightly affected by the same spin-flip effect and then shall provide a better platform to determine the color-octet matrix elements.Comment: 19 pages, 5 figures. References added. Revised version to be published in Phys.Rev.

    Electromagnetic counterparts of high-frequency gravitational waves having additional polarization states: distinguishing and probing tensor-mode, vector-mode and scalar-mode gravitons

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    GWs from extra dimensions, very early universe, and some high-energy astrophysical process, might have at most six polarizations: plus- and cross-type (tensor-mode gravitons), x-, y-type (vector-mode), and b-, l-type (scalar-mode). Peak or partial peak regions of some of such GWs are just distributed in GHz or higher frequency band, which would be optimal band for electromagnetic(EM) response. In this paper we investigate EM response to such high-frequency GWs(HFGWs) having additional polarizations. For the first time we address:(1)concrete forms of analytic solutions for perturbed EM fields caused by HFGWs having all six possible polarizations in background stable EM fields; (2)perturbed EM signals of HFGWs with additional polarizations in three-dimensional-synchro-resonance-system(3DSR system) and in galactic-extragalactic background EM fields. These perturbative EM fields are actually EM counterparts of HFGWs, and such results provide a novel way to simultaneously distinguish and display all possible six polarizations. It is also shown: (i)In EM response, pure cross-, x-type and pure y-type polarizations can independently generate perturbative photon fluxes(PPFs, signals), while plus-, b- and l-type polarizations produce PPFs in different combination states. (ii) All such six polarizations have separability and detectability. (iii)In EM response to HFGWs from extra-dimensions, distinguishing and displaying different polarizations would be quite possible due to their very high frequencies, large energy densities and special properties of spectrum. (iv)Detection band(10^8 to 10^12 Hz or higher) of PPFs by 3DSR and observation range(7*10^7 to 3*10^9 Hz) of PPFs by FAST (Five-hundred-meter-Aperture-Spherical Telescope, China), have a certain overlapping property, so their coincidence experiments will have high complementarity.Comment: 27 pages, 16 figure

    Effective SU(2)_L x U(1) theory and the Higgs boson mass

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    We assume the stability of vacuum under radiative corrections in the context of the standard electroweak theory. We find that this theory behaves as a good effective model already at cut off energy scales as low as 0.7 TeV. This stability criterion allows to predict m_H= 318 +- 13 GeV for the Higgs boson mass.Comment: Latex, 5 pages, 1 Postscript figure include

    BKB\to K Transition Form Factor with Tensor Current within the kTk_T Factorization Approach

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    In the paper, we apply the kTk_T factorization approach to deal with the BKB\to K transition form factor with tensor current in the large recoil regions. Main uncertainties for the estimation are discussed and we obtain FTBK(0)=0.25±0.01±0.02F_T^{B\to K}(0)=0.25\pm0.01\pm0.02, where the first error is caused by the uncertainties from the pionic wave functions and the second is from that of the B-meson wave functions. This result is consistent with the light-cone sum rule results obtained in the literature.Comment: 8 pages, 4 figures, references adde

    Two body final states production in electron-positron annihilation and their contributions to (g2)μ(g-2)_{\mu}

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    In this paper, we study the processes of e+ee^{+}e^{-} annihilation into two body final states, either two pseudoscalar mesons or one meson with a photon. The hadronic vacuum polarization form factors are calculated within the framework of resonance chiral theory in the energy region of E2E \lesssim 2 GeV, with final state interactions taken into account. A joint analysis on the processes of e+eπ+πe^{+}e^{-} \rightarrow \pi^{+}\pi^{-}, K+KK^{+}K^{-}, KL0KS0K_{L}^{0}K_{S}^{0}, π0γ\pi^{0}\gamma, and ηγ\eta\gamma has been performed, and the latest experimental data are included. Based on the vacuum polarization form factors of these processes, we estimate their contributions to the lowest order of anomalous magnetic moment of the muon, (g2)μ(g-2)_\mu. Combined with other contributions from hadronic vacuum polarization and other interactions from the standard model, the discrepancy between theoretical prediction and experimental measurement is Δaμ=(24.1±5.4)×1010\Delta a_{\mu}=(24.1\pm5.4)\times 10^{-10}, i.e., 4.5σ\sigma.Comment: 45 pages, 6 figures, to be the same as the published versio

    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.