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1.
In this article, we assume that there exist scalar D*[`(D)]*{D}^{\ast}{\bar {D}}^{\ast}, Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*{B}^{\ast}{\bar {B}}^{\ast} and Bs*[`(B)]s*{B}_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states, and study their masses using the QCD sum rules. The numerical results indicate that the masses are about (250–500) MeV above the corresponding D *–[`(D)]*{\bar{D}}^{\ast}, D s *–[`(D)]s*{\bar {D}}_{s}^{\ast}, B *–[`(B)]*{\bar{B}}^{\ast} and B s *–[`(B)]s*{\bar {B}}_{s}^{\ast} thresholds, the Y(4140) is unlikely a scalar Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state. The scalar D*[`(D)]*D^{\ast}{\bar{D}}^{\ast}, Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*B^{\ast}{\bar{B}}^{\ast} and Bs*[`(B)]s*B_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states maybe not exist, while the scalar D*[`(D)]¢*{D'}^{\ast}{\bar{D}}^{\prime\ast}, Ds¢*[`(D)]s¢*{D}_{s}^{\prime\ast}{\bar{D}}_{s}^{\prime\ast}, B¢*[`(B)]¢*{B}^{\prime\ast}{\bar{B}}^{\prime\ast} and Bs¢*[`(B)]s¢*{B}_{s}^{\prime\ast}{\bar{B}}_{s}^{\prime\ast} molecular states maybe exist.  相似文献   

2.
A gauge model featuring a chiral color symmetry of quarks was considered, and possible manifestations of this symmetry in proton-antiproton and proton-proton collisions at the Tevatron and LHC energies were studied. The cross section st[`(t)]\sigma _{t\bar t} for the production of t[`(t)]t\bar t quark pairs at the Tevatron and the forward-backward asymmetry AFBp[`(p)]A_{FB}^{p\bar p} in this process were calculated and analyzed with allowance for the contributions of the G′-boson predicted by the chiral color symmetry of quarks, the G′-boson massm G and the mixing angle θ G being treated as free parameters of the model. Limits on m G versus θ G were studied on the basis of data from the Tevatron on st[`(t)]\sigma _{t\bar t} and AFBp[`(p)]A_{FB}^{p\bar p}, and the region compatible with these data within one standard deviation was found in the m G-θ G plane. The region ofm G-mass values that is appropriate for observing the G′-boson at LHC is discussed.  相似文献   

3.
A new approach to the diffusion-limited reaction rate theory is developed on the base of a similar approach to consideration of Brownian coagulation, recently proposed by the author. The traditional diffusion approach to calculation of the reaction rate is critically analyzed. In particular, it is shown that the traditional approach is applicable only to the special case of reactions with a large reaction radius, [`(r)]A << RAB << [`(r)]B\bar r_A \ll R_{AB} \ll \bar r_B (where [`(r)]A\bar r_A, [`(r)]B\bar r_B are the mean interparticle distances), and becomes inappropriate to calculation of the reaction rate in the case of a relatively small reaction radius, RAB << [`(r)]AR_{AB} \ll \bar r_A, [`(r)]B\bar r_B. In the latter, most general case particles collisions occurmainly in the kinetic regime (rather than in the diffusion one) characterized by a homogeneous (at random) spatial distribution of particles. Homogenization of particles distribution occurs owing to particles diffusion mixing on the length scale of the mean interparticle distance with the characteristic diffusion time being small in comparison with the characteristic reaction time. The calculated reaction rate for a small reaction radius in 3D formally (and casually) coincides with the expression derived in the traditional approach for reactions with a large reaction radius, however, notably deviates at large times from the traditional result in the plane (2D) geometry.  相似文献   

4.
In this article, we study the mass spectrum of the baryon-antibaryon bound states p [`(p)] \bar{{p}} , S \Sigma [`(S)] \bar{{\Sigma}} , X \Xi [`(X)] \bar{{\Xi}} , L \Lambda [`(L)] \bar{{\Lambda}} , p [`(N)] \bar{{N}}(1440) , S \Sigma [`(S)] \bar{{\Sigma}}(1660) , X \Xi [`(X)] \bar{{\Xi}}^{{\prime}}_{} and L \Lambda [`(L)] \bar{{\Lambda}}(1600) with the Bethe-Salpeter equation. The numerical results indicate that the p [`(p)] \bar{{p}} , S \Sigma [`(S)] \bar{{\Sigma}} , X \Xi [`(X)] \bar{{\Xi}} , p [`(N)] \bar{{N}}(1440) , S \Sigma [`(S)] \bar{{\Sigma}}(1660) , X \Xi [`(X)] \bar{{\Xi}}^{{\prime}}_{} bound states maybe exist, and the new resonances X(1835) and X(2370) can be tentatively identified as the p [`(p)] \bar{{p}} and p [`(N)] \bar{{N}}(1440) (or N(1400)[`(p)] \bar{{p}} bound states, respectively, with some gluon constituents, and the new resonance X(2120) may be a pseudoscalar glueball. On the other hand, the Regge trajectory favors identifying the X(1835) , X(2120) and X(2370) as the excited h \eta^{{\prime}}_{}(958) mesons with the radial quantum numbers n = 3 , 4 and 5, respectively.  相似文献   

5.
Investigations of disperse nonmetallic inclusions in unalloyed alpha titanium VT1-0 have been performed by using transmission electron (including scanning and high-resolution) microscopy. Characteristic electron energy losses spectroscopy has shown that these inclusions are titanium carbide particles. It has been revealed that the disperse carbides are formed in the titanium hcp matrix as a phase based on the fcc sublattice of titanium atoms. The inclusion–matrix orientation relationship corresponds to the well-known Kurdyumov–Sachs and Nishiyama–Wassermann relationships [ 2[`11] 0 ]\upalpha ||[ 011 ]\updelta \text and ( 000[`1] )\upalpha ||( 1[`1] 1 )\updelta {\left[ {2\overline {11} 0} \right]_{{\upalpha }}}\parallel {\left[ {011} \right]_{{\updelta }}}{\text{ and }}{\left( {000\overline 1 } \right)_{{\upalpha }}}\parallel {\left( {1\overline 1 1} \right)_{{\updelta }}} .  相似文献   

6.
7.
The polarizations of Λ and [`\varLambda]{\bar{\varLambda}} are thought to retain memories of the spins of their parent s quarks and [`(s)]{\bar{s}} antiquarks, and are readily measurable via the angular distributions of their daughter protons and antiprotons. Correlations between the spins of Λ and [`\varLambda]{\bar{\varLambda}} produced at low relative momenta may therefore be used to probe the spin states of s [`(s)]s {\bar{s}} pairs produced during hadronization. We consider the possibilities that they are produced in a 3P0 state, as might result from fluctuations in the magnitude of á[`(s)] s ?\langle {\bar{s}} s \rangle, a 1S0 state, as might result from chiral fluctuations, or a 3S1 or other spin state, as might result from production by a quark–antiquark or gluon pair. We provide templates for the p [`(p)]p {\bar{p}} angular correlations that would be expected in each of these cases, and discuss how they might be used to distinguish s [`(s)]s {\bar{s}} production mechanisms in pp and heavy-ion collisions.  相似文献   

8.
In Deng et al. (Eur. Phys. J. C 70:113, 2010), we have dealt with the production of the two color-singlet S-wave (c[`(b)])(c\bar{b})-quarkonium states Bc(|(c[`(b)])1[1S0]?)B_{c}(|(c\bar {b})_{\mathbf{1}}[^{1}S_{0}]\rangle) and B*c(|(c[`(b)])1[3S1]?)B^{*}_{c}(|(c\bar{b})_{\mathbf{1}}[^{3}S_{1}]\rangle) through the Z 0 boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (c[`(b)])(c\bar{b})-quarkonium states, i.e. |(c[`(b)])1[1P1]?|(c\bar{b})_{\mathbf{1}}[^{1}P_{1}]\rangle and |(c[`(b)])1[3PJ]?|(c\bar{b})_{\mathbf{1}}[^{3}P_{J}]\rangle (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(c[`(b)])8[1S0]g?|(c\bar{b})_{\mathbf{8}}[^{1}S_{0}]g\rangle and |(c[`(b)])8[3S1]g?|(c\bar{b})_{\mathbf{8}}[^{3}S_{1}]g\rangle, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the B c production, whose decay width is about 20% of the total decay width \varGamma Z0? Bc\varGamma _{Z^{0}\to B_{c}}. After summing up all the mentioned (c[`(b)])(c\bar {b})-quarkonium states’ contributions, we obtain \varGamma Z0? Bc=235.9+352.8-122.0\varGamma _{Z^{0}\to B_{c}}=235.9^{+352.8}_{-122.0} KeV, where the errors are caused by the main sources of uncertainty.  相似文献   

9.
Percolation theory is extensively studied in statistical physics and mathematics with applications in diverse fields. However, the research is focused on systems with only one type of links, connectivity links. We review a recently developed mathematical framework for analyzing percolation properties of realistic scenarios of networks having links of two types, connectivity and dependency links. This formalism was applied to study Erdős-Rényi (ER) networks that include also dependency links. For an ER network with average degree [`(k)]\bar{k} that is composed of dependency clusters of size s, the fraction of nodes that belong to the giant component, P , is given by P=ps-1[1-exp(-[`(k)]pP) ]sP_{\infty}=p^{s-1}[1-\exp{(-\bar{k}pP_{\infty})} ]^{s} where 1−p is the initial fraction of randomly removed nodes. Here, we apply the formalism to the study of random-regular (RR) networks and find a formula for the size of the giant component in the percolation process: P =p s−1(1−r k ) s where r is the solution of r=p s (r k−1−1)(1−r k )+1, and k is the degree of the nodes. These general results coincide, for s=1, with the known equations for percolation in ER and RR networks respectively without dependency links. In contrast to s=1, where the percolation transition is second order, for s>1 it is of first order. Comparing the percolation behavior of ER and RR networks we find a remarkable difference regarding their resilience. We show, analytically and numerically, that in ER networks with low connectivity degree or large dependency clusters, removal of even a finite number (zero fraction) of the infinite network nodes will trigger a cascade of failures that fragments the whole network. Specifically, for any given s there exists a critical degree value, [`(k)]min\bar{k}_{\min}, such that an ER network with [`(k)] £ [`(k)]min\bar{k}\leq \bar{k}_{\min} is unstable and collapse when removing even a single node. This result is in contrast to RR networks where such cascades and full fragmentation can be triggered only by removal of a finite fraction of nodes in the network.  相似文献   

10.
We introduce an alternative approach to the third order helicity of a volume preserving vector field B, which leads us to a lower bound for the L 2-energy of B. The proposed approach exploits correspondence between the Milnor [`(m)]123{\bar{\mu}_{123}} -invariant for 3-component links and the homotopy invariants of maps to configuration spaces, and we provide a simple geometric proof of this fact in the case of Borromean links. Based on these connections we develop a formulation for the third order helicity of B on invariant unlinked domains of B, and provide Arnold’s style ergodic interpretation of this invariant as an average asymptotic [`(m)]123{\bar{\mu}_{123}} -invariant of orbits of B.  相似文献   

11.
The new intermediate entangled state |η;θ〉 is proposed by virtue of IWOP technique, which is the common eigenvector of [([^(x)]1 - [^(x)]2)cosq-([^(p)]1 - [^(p)]2)sinq][(\hat{x}_{1} - \hat{x}_{2})\cos\theta -(\hat{p}_{1} - \hat{p}_{2})\sin\theta ] and [([^(x)]1 +[^(x)]2)sinq+ ([^(p)]1 + [^(p)]2)cosq][(\hat{x}_{1} +\hat{x}_{2})\sin\theta + (\hat{p}_{1} + \hat{p}_{2})\cos\theta ]. The squeezing transformation operator, Hadamard transformation operator, Fresnel transformation operator and Radon transform operator are constructed by |η;θ〉.  相似文献   

12.
In this article, we assume that there exists a scalar Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state in the J/ψ φ invariant mass distribution, and we study its mass using the QCD sum rules. The predictions depend heavily on the two criteria (pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about MDs*[`(D)]s*=(4.43±0.16)M_{D_{s}^{\ast}{\bar{D}}_{s}^{\ast}}=(4.43\pm0.16)  GeV, which is inconsistent with the experimental data. The Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast} is probably a virtual state and is not related to the meson Y(4140). Another possibility, such as a hybrid charmonium, is not excluded.  相似文献   

13.
This paper considers Hardy–Lieb–Thirring inequalities for higher order differential operators. A result for general fourth-order operators on the half-line is developed, and the trace inequality
tr( (-D)2 - CHRd,2\frac1|x|4 - V(x) )-gCgò\mathbbRd V(x)+g+ \fracd4 dx,     g 3 1 - \frac d 4,\mathrm{tr}\left( (-\Delta)^2 - C^{\mathrm{HR}}_{d,2}\frac{1}{|x|^4} - V(x) \right)_-^{\gamma}\leq C_\gamma\int\limits_{\mathbb{R}^d} V(x)_+^{\gamma + \frac{d}{4}}\,\mathrm{d}x, \quad \gamma \geq 1 - \frac d 4,  相似文献   

14.
The light flavor antiquark distributions of the nucleon sea are calculated in the effective chiral quark model and compared with experimental results. The contributions of the flavor-symmetric sea-quark distributions and the nuclear EMC effect are taken into account to obtain the ratio of Drell–Yan cross sections σ pD/2σ pp, which can match well with the results measured in the FermiLab E866/NuSea experiment. The calculated results also match the [`(d)](x)-[`(u)](x)\bar{d}(x)-\bar{u}(x) measured in different experiments, but unmatch the behavior of [`(d)](x)/[`(u)](x)\bar{d}(x)/\bar{u}(x) derived indirectly from the measurable quantity σ pD/2σ pp by the FermiLab E866/NuSea Collaboration at large x. We suggest to measure again [`(d)](x)/[`(u)](x)\bar{d}(x)/\bar{u}(x) at large x from precision experiments with careful treatment of the experimental data. We also propose an alternative procedure for experimental data treatment.  相似文献   

15.
The conductivity of glasses in the 50\textP\text2 \textO\text5 - x\textV\text2 \textO\text5 - ( 50 - x )\textLi\text2 \textO50{\text{P}}_{\text{2}} {\text{O}}_{\text{5}} - x{\text{V}}_{\text{2}} {\text{O}}_{\text{5}} - \left( {50 - x} \right){\text{Li}}_{\text{2}} {\text{O}} system was studied as a function of temperature and composition. For all compositions, the conductivity variation as a function of temperature followed an Arrhenius type relationship. Isothermal variation of conductivity as a function of composition showed a minimum for a molar ratio x near 20. Probable mechanisms for decrease of conductivity with decrease of vanadium oxide concentration were explained. The minimum in room temperature was attributed to increase of V4+/V5+ with decrease of vanadium oxide in specific concentrations of vanadium oxide. Activation energy increased with decrease of V2O5 content. This behavior was attributed to increase of average spacing between vanadium ions.  相似文献   

16.
A model-independent analysis of anomalous gauge coupling constants of W ± bosons is presented and the corresponding restrictions on them and on the electromagnetic characteristics of W ± bosons following from the experiments on measuring the e+ e- ? W+ W- ? ( e
/ m, [`(v)] ) ?( q,[`(q)] ) {e^{+} }{e^{-} } \to {W^{+} }{W^{-} } \to \left( {{{e} \left/ {{\mu, \bar{v}}} \right.}} \right) \oplus \left( {q,\bar{q}} \right) process on the e + e International Linear Collider are obtained. The method of obtaining the model-independent restrictions on the anomalous gauge constants is based on the use of the polarization scattering cross sections for different initial and final polarization states.  相似文献   

17.
A new interpretation is introduced for MOND based on the Sciama’s interpretation of Mach principle and an Unruh like effect, in the context of a generalized equivalence principle. It is argued that in a locally accelerated frame with acceleration a the appearance of a Rindler horizon may give rise to a constant acceleration a 0 as the local properties of cosmological horizon or Hubble length. The total gravitational acceleration inside this frame becomes the combination of a with a 0. For aa 0, the conventional gravitational mass m g interacts with the dominant acceleration as m g a and application of Sciama’s interpretation leads to the standard Newtonian dynamics. For aa 0, however, a reduced gravitational mass [`(m)]g\bar{m}_{g} interacts with the dominant acceleration as [`(m)]ga0\bar{m}_{g}a_{0} and the application of Sciama’s interpretation on this reduced gravitational mass leads to MOND. This introduces a third proposal for MOND: The modification of gravitational mass.  相似文献   

18.
We analyze the long time behavior of solutions of the Schrödinger equation ${i\psi_t=(-\Delta-b/r+V(t,x))\psi}We analyze the long time behavior of solutions of the Schr?dinger equation iyt=(-D-b/r+V(t,x))y{i\psi_t=(-\Delta-b/r+V(t,x))\psi}, x ? \mathbbR3{x\in\mathbb{R}^3}, r =  |x|, describing a Coulomb system subjected to a spatially compactly supported time periodic potential V(t, x) =  V(t +  2π/ω, x) with zero time average.  相似文献   

19.
The interpretation of Y(4140) as a D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} molecule is studied dynamically in the one boson exchange approach, where σ, η and φ exchange are included. Ten allowed D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} states with low spin parity are considered, and we find that the J PC =0++, 1+−, 0−+, 2++ and 1−− D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} configurations are most tightly bound. We suggest that the most favorable quantum numbers are J PC =0++ for Y(4140) as a D*s[`(D)]*sD^{*}_{s}\bar{D}^{*}_{s} molecule; however, J PC =0−+ and 2++ cannot be excluded. We propose to search for the 1+− and 1−− partners in the J/ψ η and J/ψ η′ final states, which is an important test of the molecular hypothesis of Y(4140) and the reasonability of our model. The 0++ B*s[`(B)]*sB^{*}_{s}\bar{B}^{*}_{s} molecule should be deeply bound; experimental search in the ϒ(1S)φ channel at Tevatron and LHC is suggested.  相似文献   

20.
We study the expansion properties of the contracting Lorenz flow introduced by Rovella via thermodynamic formalism. Specifically, we prove the existence of an equilibrium state for the natural potential [^( j)]t(x,y,z):=-tlogJ(x,y,z)cu\hat{ \varphi }_{t}(x,y,z):=-t\log J_{(x,y,z)}^{cu} for the contracting Lorenz flow and for t in an interval containing [0,1]. We also analyse the Lyapunov spectrum of the flow in terms of the pressure.  相似文献   

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